Merge remote-tracking branch 'upstream/master' into usermarksusermarks

1 files changed, 1429 insertions, 1299 deletions

diff --git a/src/nvim/tag.c b/src/nvim/tag.c
index 65c56bf01b..197184c181 100644
--- a/src/nvim/tag.c
+++ b/src/nvim/tag.c
@@ -1,34 +1,41 @@
 // This is an open source non-commercial project. Dear PVS-Studio, please check
 // it. PVS-Studio Static Code Analyzer for C, C++ and C#: http://www.viva64.com
 
-/*
- * Code to handle tags and the tag stack
- */
+// Code to handle tags and the tag stack
 
 #include <assert.h>
+#include <ctype.h>
 #include <inttypes.h>
 #include <stdbool.h>
+#include <stdio.h>
+#include <stdlib.h>
 #include <string.h>
 
 #include "nvim/ascii.h"
+#include "nvim/autocmd.h"
 #include "nvim/buffer.h"
 #include "nvim/charset.h"
 #include "nvim/cmdexpand.h"
 #include "nvim/cursor.h"
 #include "nvim/drawscreen.h"
-#include "nvim/edit.h"
 #include "nvim/eval.h"
+#include "nvim/eval/typval.h"
+#include "nvim/eval/typval_defs.h"
 #include "nvim/ex_cmds.h"
+#include "nvim/ex_cmds_defs.h"
 #include "nvim/ex_docmd.h"
-#include "nvim/ex_getln.h"
 #include "nvim/file_search.h"
 #include "nvim/fileio.h"
 #include "nvim/fold.h"
 #include "nvim/garray.h"
+#include "nvim/gettext.h"
+#include "nvim/globals.h"
+#include "nvim/hashtab.h"
 #include "nvim/help.h"
-#include "nvim/if_cscope.h"
+#include "nvim/highlight_defs.h"
 #include "nvim/input.h"
 #include "nvim/insexpand.h"
+#include "nvim/macros.h"
 #include "nvim/mark.h"
 #include "nvim/mbyte.h"
 #include "nvim/memory.h"
@@ -38,49 +45,47 @@
 #include "nvim/optionstr.h"
 #include "nvim/os/input.h"
 #include "nvim/os/os.h"
+#include "nvim/os/os_defs.h"
 #include "nvim/os/time.h"
-#include "nvim/os_unix.h"
 #include "nvim/path.h"
+#include "nvim/pos.h"
 #include "nvim/quickfix.h"
 #include "nvim/regexp.h"
 #include "nvim/runtime.h"
 #include "nvim/search.h"
 #include "nvim/strings.h"
 #include "nvim/tag.h"
+#include "nvim/types.h"
 #include "nvim/ui.h"
 #include "nvim/vim.h"
 #include "nvim/window.h"
 
-/*
- * Structure to hold pointers to various items in a tag line.
- */
+// Structure to hold pointers to various items in a tag line.
 typedef struct tag_pointers {
   // filled in by parse_tag_line():
-  char_u *tagname;  // start of tag name (skip "file:")
-  char_u *tagname_end;  // char after tag name
-  char_u *fname;   // first char of file name
-  char_u *fname_end;  // char after file name
-  char_u *command;  // first char of command
+  char *tagname;        // start of tag name (skip "file:")
+  char *tagname_end;    // char after tag name
+  char *fname;          // first char of file name
+  char *fname_end;      // char after file name
+  char *command;        // first char of command
   // filled in by parse_match():
-  char_u *command_end;  // first char after command
-  char_u *tag_fname;  // file name of the tags file. This is used
+  char *command_end;    // first char after command
+  char *tag_fname;      // file name of the tags file. This is used
   // when 'tr' is set.
-  char_u *tagkind;  // "kind:" value
-  char_u *tagkind_end;  // end of tagkind
-  char_u *user_data;  // user_data string
-  char_u *user_data_end;  // end of user_data
-  linenr_T tagline;        // "line:" value
+  char *tagkind;          // "kind:" value
+  char *tagkind_end;      // end of tagkind
+  char *user_data;        // user_data string
+  char *user_data_end;    // end of user_data
+  linenr_T tagline;       // "line:" value
 } tagptrs_T;
 
-/*
- * Structure to hold info about the tag pattern being used.
- */
+// Structure to hold info about the tag pattern being used.
 typedef struct {
-  char_u *pat;             // the pattern
-  int len;                      // length of pat[]
-  char_u *head;            // start of pattern head
-  int headlen;                  // length of head[]
-  regmatch_T regmatch;          // regexp program, may be NULL
+  char *pat;            // the pattern
+  int len;              // length of pat[]
+  char *head;           // start of pattern head
+  int headlen;          // length of head[]
+  regmatch_T regmatch;  // regexp program, may be NULL
 } pat_T;
 
 // The matching tags are first stored in one of the hash tables.  In
@@ -88,45 +93,163 @@ typedef struct {
 // ht_match[] is used to find duplicates, ga_match[] to keep them in sequence.
 // At the end, the matches from ga_match[] are concatenated, to make a list
 // sorted on priority.
-#define MT_ST_CUR       0               // static match in current file
-#define MT_GL_CUR       1               // global match in current file
-#define MT_GL_OTH       2               // global match in other file
-#define MT_ST_OTH       3               // static match in other file
-#define MT_IC_OFF       4               // add for icase match
-#define MT_RE_OFF       8               // add for regexp match
-#define MT_MASK         7               // mask for printing priority
-#define MT_COUNT        16
+enum {
+  MT_ST_CUR = 0,  // static match in current file
+  MT_GL_CUR = 1,  // global match in current file
+  MT_GL_OTH = 2,  // global match in other file
+  MT_ST_OTH = 3,  // static match in other file
+  MT_IC_OFF = 4,  // add for icase match
+  MT_RE_OFF = 8,  // add for regexp match
+  MT_MASK = 7,    // mask for printing priority
+  MT_COUNT = 16,
+};
 
 static char *mt_names[MT_COUNT/2] =
 { "FSC", "F C", "F  ", "FS ", " SC", "  C", "   ", " S " };
 
 #define NOTAGFILE       99              // return value for jumpto_tag
-static char_u *nofile_fname = NULL;   // fname for NOTAGFILE error
+static char *nofile_fname = NULL;       // fname for NOTAGFILE error
+
+/// Return values used when reading lines from a tags file.
+typedef enum {
+  TAGS_READ_SUCCESS = 1,
+  TAGS_READ_EOF,
+  TAGS_READ_IGNORE,
+} tags_read_status_T;
+
+/// States used during a tags search
+typedef enum {
+  TS_START,         ///< at start of file
+  TS_LINEAR,        ///< linear searching forward, till EOF
+  TS_BINARY,        ///< binary searching
+  TS_SKIP_BACK,     ///< skipping backwards
+  TS_STEP_FORWARD,  ///< stepping forwards
+} tagsearch_state_T;
+
+/// Binary search file offsets in a tags file
+typedef struct {
+  off_T low_offset;        ///< offset for first char of first line that
+                           ///< could match
+  off_T high_offset;       ///< offset of char after last line that could
+                           ///< match
+  off_T curr_offset;       ///< Current file offset in search range
+  off_T curr_offset_used;  ///< curr_offset used when skipping back
+  off_T match_offset;      ///< Where the binary search found a tag
+  int low_char;            ///< first char at low_offset
+  int high_char;           ///< first char at high_offset
+} tagsearch_info_T;
+
+/// Return values used when matching tags against a pattern.
+typedef enum {
+  TAG_MATCH_SUCCESS = 1,
+  TAG_MATCH_FAIL,
+  TAG_MATCH_STOP,
+  TAG_MATCH_NEXT,
+} tagmatch_status_T;
+
+/// Arguments used for matching tags read from a tags file against a pattern.
+typedef struct {
+  int matchoff;      ///< tag match offset
+  bool match_re;     ///< true if the tag matches a regexp
+  bool match_no_ic;  ///< true if the tag matches with case
+  bool has_re;       ///< regular expression used
+  bool sortic;       ///< tags file sorted ignoring case (foldcase)
+  bool sort_error;   ///< tags file not sorted
+} findtags_match_args_T;
+
+/// State information used during a tag search
+typedef struct {
+  tagsearch_state_T state;       ///< tag search state
+  bool stop_searching;           ///< stop when match found or error
+  pat_T *orgpat;                 ///< holds unconverted pattern info
+  char *lbuf;                    ///< line buffer
+  int lbuf_size;                 ///< length of lbuf
+  char *tag_fname;               ///< name of the tag file
+  FILE *fp;                      ///< current tags file pointer
+  int flags;                     ///< flags used for tag search
+  int tag_file_sorted;           ///< !_TAG_FILE_SORTED value
+  bool get_searchpat;            ///< used for 'showfulltag'
+  bool help_only;                ///< only search for help tags
+  bool did_open;                 ///< did open a tag file
+  int mincount;                  ///< MAXCOL: find all matches
+                                 ///< other: minimal number of matches
+  bool linear;                   ///< do a linear search
+  vimconv_T vimconv;
+  char help_lang[3];             ///< lang of current tags file
+  int help_pri;                  ///< help language priority
+  char *help_lang_find;          ///< lang to be found
+  bool is_txt;                   ///< flag of file extension
+  int match_count;               ///< number of matches found
+  garray_T ga_match[MT_COUNT];   ///< stores matches in sequence
+  hashtab_T ht_match[MT_COUNT];  ///< stores matches by key
+} findtags_state_T;
 
 #ifdef INCLUDE_GENERATED_DECLARATIONS
 # include "tag.c.generated.h"
 #endif
 
-static char_u *bottommsg = (char_u *)N_("E555: at bottom of tag stack");
-static char_u *topmsg = (char_u *)N_("E556: at top of tag stack");
-static char_u *recurmsg
-  = (char_u *)N_("E986: cannot modify the tag stack within tagfunc");
-static char_u *tfu_inv_ret_msg
-  = (char_u *)N_("E987: invalid return value from tagfunc");
+static char *bottommsg = N_("E555: at bottom of tag stack");
+static char *topmsg = N_("E556: at top of tag stack");
+static char *recurmsg = N_("E986: cannot modify the tag stack within tagfunc");
+static char *tfu_inv_ret_msg = N_("E987: invalid return value from tagfunc");
+static char e_window_unexpectedly_close_while_searching_for_tags[]
+  = N_("E1299: Window unexpectedly closed while searching for tags");
 
-static char_u *tagmatchname = NULL;   // name of last used tag
+static char *tagmatchname = NULL;   // name of last used tag
 
-/*
- * Tag for preview window is remembered separately, to avoid messing up the
- * normal tagstack.
- */
+// Tag for preview window is remembered separately, to avoid messing up the
+// normal tagstack.
 static taggy_T ptag_entry = { NULL, INIT_FMARK, 0, 0, NULL };
 
 static int tfu_in_use = false;  // disallow recursive call of tagfunc
+static Callback tfu_cb;         // 'tagfunc' callback function
 
 // Used instead of NUL to separate tag fields in the growarrays.
 #define TAG_SEP 0x02
 
+/// Reads the 'tagfunc' option value and convert that to a callback value.
+/// Invoked when the 'tagfunc' option is set. The option value can be a name of
+/// a function (string), or function(<name>) or funcref(<name>) or a lambda.
+void set_tagfunc_option(char **errmsg)
+{
+  callback_free(&tfu_cb);
+  callback_free(&curbuf->b_tfu_cb);
+
+  if (*curbuf->b_p_tfu == NUL) {
+    return;
+  }
+
+  if (option_set_callback_func(curbuf->b_p_tfu, &tfu_cb) == FAIL) {
+    *errmsg = e_invarg;
+  }
+
+  callback_copy(&curbuf->b_tfu_cb, &tfu_cb);
+}
+
+#if defined(EXITFREE)
+void free_tagfunc_option(void)
+{
+  callback_free(&tfu_cb);
+}
+#endif
+
+/// Mark the global 'tagfunc' callback with "copyID" so that it is not garbage
+/// collected.
+bool set_ref_in_tagfunc(int copyID)
+{
+  return set_ref_in_callback(&tfu_cb, copyID, NULL, NULL);
+}
+
+/// Copy the global 'tagfunc' callback function to the buffer-local 'tagfunc'
+/// callback for 'buf'.
+void set_buflocal_tfu_callback(buf_T *buf)
+{
+  callback_free(&buf->b_tfu_cb);
+  if (tfu_cb.type != kCallbackNone) {
+    callback_copy(&buf->b_tfu_cb, &tfu_cb);
+  }
+}
+
 /// Jump to tag; handling of tag commands and tag stack
 ///
 /// *tag != NUL: ":tag {tag}", jump to new tag, add to tag stack
@@ -140,16 +263,13 @@ static int tfu_in_use = false;  // disallow recursive call of tagfunc
 /// type == DT_LAST:     jump to last match of same tag
 /// type == DT_SELECT:   ":tselect [tag]", select tag from a list of all matches
 /// type == DT_JUMP:     ":tjump [tag]", jump to tag or select tag from a list
-/// type == DT_CSCOPE:   use cscope to find the tag
 /// type == DT_LTAG:     use location list for displaying tag matches
 /// type == DT_FREE:     free cached matches
 ///
-/// for cscope, returns true if we jumped to tag or aborted, false otherwise
-///
 /// @param tag  tag (pattern) to jump to
 /// @param forceit  :ta with !
 /// @param verbose  print "tag not found" message
-bool do_tag(char_u *tag, int type, int count, int forceit, int verbose)
+void do_tag(char *tag, int type, int count, int forceit, int verbose)
 {
   taggy_T *tagstack = curwin->w_tagstack;
   int tagstackidx = curwin->w_tagstackidx;
@@ -166,13 +286,13 @@ bool do_tag(char_u *tag, int type, int count, int forceit, int verbose)
   int error_cur_match = 0;
   int save_pos = false;
   fmark_T saved_fmark;
-  bool jumped_to_tag = false;
   int new_num_matches;
   char **new_matches;
   int use_tagstack;
   int skip_msg = false;
-  char_u *buf_ffname = (char_u *)curbuf->b_ffname;  // name for priority computation
+  char *buf_ffname = curbuf->b_ffname;  // name for priority computation
   int use_tfu = 1;
+  char *tofree = NULL;
 
   // remember the matches for the last used tag
   static int num_matches = 0;
@@ -182,16 +302,15 @@ bool do_tag(char_u *tag, int type, int count, int forceit, int verbose)
 
   if (tfu_in_use) {
     emsg(_(recurmsg));
-    return false;
+    return;
   }
 
 #ifdef EXITFREE
   if (type == DT_FREE) {
     // remove the list of matches
     FreeWild(num_matches, matches);
-    cs_free_tags();
     num_matches = 0;
-    return false;
+    return;
   }
 #endif
 
@@ -215,7 +334,7 @@ bool do_tag(char_u *tag, int type, int count, int forceit, int verbose)
     new_tag = true;
     if (g_do_tagpreview != 0) {
       tagstack_clear_entry(&ptag_entry);
-      ptag_entry.tagname = vim_strsave(tag);
+      ptag_entry.tagname = xstrdup(tag);
     }
   } else {
     if (g_do_tagpreview != 0) {
@@ -227,25 +346,21 @@ bool do_tag(char_u *tag, int type, int count, int forceit, int verbose)
     // new pattern, add to the tag stack
     if (*tag != NUL
         && (type == DT_TAG || type == DT_SELECT || type == DT_JUMP
-            || type == DT_LTAG
-            || type == DT_CSCOPE
-            )) {
+            || type == DT_LTAG)) {
       if (g_do_tagpreview != 0) {
         if (ptag_entry.tagname != NULL
-            && STRCMP(ptag_entry.tagname, tag) == 0) {
+            && strcmp(ptag_entry.tagname, tag) == 0) {
           // Jumping to same tag: keep the current match, so that
           // the CursorHold autocommand example works.
           cur_match = ptag_entry.cur_match;
           cur_fnum = ptag_entry.cur_fnum;
         } else {
           tagstack_clear_entry(&ptag_entry);
-          ptag_entry.tagname = vim_strsave(tag);
+          ptag_entry.tagname = xstrdup(tag);
         }
       } else {
-        /*
-         * If the last used entry is not at the top, delete all tag
-         * stack entries above it.
-         */
+        // If the last used entry is not at the top, delete all tag
+        // stack entries above it.
         while (tagstackidx < tagstacklen) {
           tagstack_clear_entry(&tagstack[--tagstacklen]);
         }
@@ -261,7 +376,7 @@ bool do_tag(char_u *tag, int type, int count, int forceit, int verbose)
         }
 
         // put the tag name in the tag stack
-        tagstack[tagstackidx].tagname = vim_strsave(tag);
+        tagstack[tagstackidx].tagname = xstrdup(tag);
 
         curwin->w_tagstacklen = tagstacklen;
 
@@ -270,8 +385,7 @@ bool do_tag(char_u *tag, int type, int count, int forceit, int verbose)
 
       new_tag = true;
     } else {
-      if (
-          g_do_tagpreview != 0 ? ptag_entry.tagname == NULL :
+      if (g_do_tagpreview != 0 ? ptag_entry.tagname == NULL :
           tagstacklen == 0) {
         // empty stack
         emsg(_(e_tagstack));
@@ -299,10 +413,8 @@ bool do_tag(char_u *tag, int type, int count, int forceit, int verbose)
         // tagstack before it's used.
         saved_fmark = tagstack[tagstackidx].fmark;
         if (saved_fmark.fnum != curbuf->b_fnum) {
-          /*
-           * Jump to other file. If this fails (e.g. because the
-           * file was changed) keep original position in tag stack.
-           */
+          // Jump to other file. If this fails (e.g. because the
+          // file was changed) keep original position in tag stack.
           if (buflist_getfile(saved_fmark.fnum, saved_fmark.mark.lnum,
                               GETF_SETMARK, forceit) == FAIL) {
             tagstackidx = oldtagstackidx;              // back to old posn
@@ -324,7 +436,6 @@ bool do_tag(char_u *tag, int type, int count, int forceit, int verbose)
 
         // remove the old list of matches
         FreeWild(num_matches, matches);
-        cs_free_tags();
         num_matches = 0;
         tag_freematch();
         goto end_do_tag;
@@ -339,11 +450,9 @@ bool do_tag(char_u *tag, int type, int count, int forceit, int verbose)
           // ":tag" (no argument): go to newer pattern
           save_pos = true;              // save the cursor position below
           if ((tagstackidx += count - 1) >= tagstacklen) {
-            /*
-             * Beyond the last one, just give an error message and
-             * go to the last one.  Don't store the cursor
-             * position.
-             */
+            // Beyond the last one, just give an error message and
+            // go to the last one.  Don't store the cursor
+            // position.
             tagstackidx = tagstacklen - 1;
             emsg(_(topmsg));
             save_pos = false;
@@ -375,7 +484,6 @@ bool do_tag(char_u *tag, int type, int count, int forceit, int verbose)
           cur_match = count - 1; break;
         case DT_SELECT:
         case DT_JUMP:
-        case DT_CSCOPE:
         case DT_LAST:
           cur_match = MAXCOL - 1; break;
         case DT_NEXT:
@@ -400,9 +508,7 @@ bool do_tag(char_u *tag, int type, int count, int forceit, int verbose)
         ptag_entry.cur_fnum = cur_fnum;
       }
     } else {
-      /*
-       * For ":tag [arg]" or ":tselect" remember position before the jump.
-       */
+      // For ":tag [arg]" or ":tselect" remember position before the jump.
       saved_fmark = tagstack[tagstackidx].fmark;
       if (save_pos) {
         tagstack[tagstackidx].fmark.mark = curwin->w_cursor;
@@ -427,32 +533,33 @@ bool do_tag(char_u *tag, int type, int count, int forceit, int verbose)
     buf_T *buf = buflist_findnr(cur_fnum);
 
     if (buf != NULL) {
-      buf_ffname = (char_u *)buf->b_ffname;
+      buf_ffname = buf->b_ffname;
     }
   }
 
-  /*
-   * Repeat searching for tags, when a file has not been found.
-   */
+  // Repeat searching for tags, when a file has not been found.
   for (;;) {
     int other_name;
-    char_u *name;
+    char *name;
 
     // When desired match not found yet, try to find it (and others).
     if (use_tagstack) {
-      name = tagstack[tagstackidx].tagname;
+      // make a copy, the tagstack may change in 'tagfunc'
+      name = xstrdup(tagstack[tagstackidx].tagname);
+      xfree(tofree);
+      tofree = name;
     } else if (g_do_tagpreview != 0) {
       name = ptag_entry.tagname;
     } else {
       name = tag;
     }
-    other_name = (tagmatchname == NULL || STRCMP(tagmatchname, name) != 0);
+    other_name = (tagmatchname == NULL || strcmp(tagmatchname, name) != 0);
     if (new_tag
         || (cur_match >= num_matches && max_num_matches != MAXCOL)
         || other_name) {
       if (other_name) {
         xfree(tagmatchname);
-        tagmatchname = vim_strsave(name);
+        tagmatchname = xstrdup(name);
       }
 
       if (type == DT_SELECT || type == DT_JUMP
@@ -473,9 +580,6 @@ bool do_tag(char_u *tag, int type, int count, int forceit, int verbose)
         flags = TAG_NOIC;
       }
 
-      if (type == DT_CSCOPE) {
-        flags = TAG_CSCOPE;
-      }
       if (verbose) {
         flags |= TAG_VERBOSE;
       }
@@ -490,6 +594,15 @@ bool do_tag(char_u *tag, int type, int count, int forceit, int verbose)
                                    // found: all matches found.
       }
 
+      // A tag function may do anything, which may cause various
+      // information to become invalid.  At least check for the tagstack
+      // to still be the same.
+      if (tagstack != curwin->w_tagstack) {
+        emsg(_(e_window_unexpectedly_close_while_searching_for_tags));
+        FreeWild(new_num_matches, new_matches);
+        break;
+      }
+
       // If there already were some matches for the same name, move them
       // to the start.  Avoids that the order changes when using
       // ":tnext" and jumping to another file.
@@ -501,15 +614,15 @@ bool do_tag(char_u *tag, int type, int count, int forceit, int verbose)
         // Find the position of each old match in the new list.  Need
         // to use parse_match() to find the tag line.
         for (j = 0; j < num_matches; j++) {
-          parse_match((char_u *)matches[j], &tagp);
+          parse_match(matches[j], &tagp);
           for (i = idx; i < new_num_matches; i++) {
-            parse_match((char_u *)new_matches[i], &tagp2);
-            if (STRCMP(tagp.tagname, tagp2.tagname) == 0) {
-              char_u *p = (char_u *)new_matches[i];
+            parse_match(new_matches[i], &tagp2);
+            if (strcmp(tagp.tagname, tagp2.tagname) == 0) {
+              char *p = new_matches[i];
               for (k = i; k > idx; k--) {
                 new_matches[k] = new_matches[k - 1];
               }
-              new_matches[idx++] = (char *)p;
+              new_matches[idx++] = p;
               break;
             }
           }
@@ -528,10 +641,7 @@ bool do_tag(char_u *tag, int type, int count, int forceit, int verbose)
     } else {
       bool ask_for_selection = false;
 
-      if (type == DT_CSCOPE && num_matches > 1) {
-        cs_print_tags();
-        ask_for_selection = true;
-      } else if (type == DT_TAG && *tag != NUL) {
+      if (type == DT_TAG && *tag != NUL) {
         // If a count is supplied to the ":tag <name>" command, then
         // jump to count'th matching tag.
         cur_match = count > 0 ? count - 1 : 0;
@@ -555,8 +665,6 @@ bool do_tag(char_u *tag, int type, int count, int forceit, int verbose)
             tagstack[tagstackidx].fmark = saved_fmark;
             tagstackidx = prevtagstackidx;
           }
-          cs_free_tags();
-          jumped_to_tag = true;
           break;
         }
         cur_match = i - 1;
@@ -584,12 +692,11 @@ bool do_tag(char_u *tag, int type, int count, int forceit, int verbose)
         tagstack[tagstackidx].cur_fnum = cur_fnum;
 
         // store user-provided data originating from tagfunc
-        if (use_tfu && parse_match((char_u *)matches[cur_match], &tagp2) == OK
+        if (use_tfu && parse_match(matches[cur_match], &tagp2) == OK
             && tagp2.user_data) {
           XFREE_CLEAR(tagstack[tagstackidx].user_data);
-          tagstack[tagstackidx].user_data = vim_strnsave(tagp2.user_data,
-                                                         (size_t)(tagp2.user_data_end -
-                                                                  tagp2.user_data));
+          tagstack[tagstackidx].user_data =
+            xstrnsave(tagp2.user_data, (size_t)(tagp2.user_data_end - tagp2.user_data));
         }
 
         tagstackidx++;
@@ -598,21 +705,18 @@ bool do_tag(char_u *tag, int type, int count, int forceit, int verbose)
         ptag_entry.cur_fnum = cur_fnum;
       }
 
-      /*
-       * Only when going to try the next match, report that the previous
-       * file didn't exist.  Otherwise an emsg() is given below.
-       */
+      // Only when going to try the next match, report that the previous
+      // file didn't exist.  Otherwise an emsg() is given below.
       if (nofile_fname != NULL && error_cur_match != cur_match) {
         smsg(_("File \"%s\" does not exist"), nofile_fname);
       }
 
       ic = (matches[cur_match][0] & MT_IC_OFF);
       if (type != DT_TAG && type != DT_SELECT && type != DT_JUMP
-          && type != DT_CSCOPE
           && (num_matches > 1 || ic)
           && !skip_msg) {
         // Give an indication of the number of matching tags
-        snprintf((char *)IObuff, sizeof(IObuff), _("tag %d of %d%s"),
+        snprintf(IObuff, sizeof(IObuff), _("tag %d of %d%s"),
                  cur_match + 1,
                  num_matches,
                  max_num_matches != MAXCOL ? _(" or more") : "");
@@ -624,11 +728,11 @@ bool do_tag(char_u *tag, int type, int count, int forceit, int verbose)
           if (ic) {
             msg_attr((const char *)IObuff, HL_ATTR(HLF_W));
           } else {
-            msg((char *)IObuff);
+            msg(IObuff);
           }
           msg_scroll = true;  // Don't overwrite this message.
         } else {
-          give_warning((char *)IObuff, ic);
+          give_warning(IObuff, ic);
         }
         if (ic && !msg_scrolled && msg_silent == 0) {
           ui_flush();
@@ -637,13 +741,11 @@ bool do_tag(char_u *tag, int type, int count, int forceit, int verbose)
       }
 
       // Let the SwapExists event know what tag we are jumping to.
-      vim_snprintf((char *)IObuff, IOSIZE, ":ta %s\r", name);
-      set_vim_var_string(VV_SWAPCOMMAND, (char *)IObuff, -1);
+      vim_snprintf(IObuff, IOSIZE, ":ta %s\r", name);
+      set_vim_var_string(VV_SWAPCOMMAND, IObuff, -1);
 
-      /*
-       * Jump to the desired match.
-       */
-      i = jumpto_tag((char_u *)matches[cur_match], forceit, type != DT_CSCOPE);
+      // Jump to the desired match.
+      i = jumpto_tag(matches[cur_match], forceit, true);
 
       set_vim_var_string(VV_SWAPCOMMAND, NULL, -1);
 
@@ -673,7 +775,6 @@ bool do_tag(char_u *tag, int type, int count, int forceit, int verbose)
         if (use_tagstack && tagstackidx > curwin->w_tagstacklen) {
           tagstackidx = curwin->w_tagstackidx;
         }
-        jumped_to_tag = true;
       }
     }
     break;
@@ -686,8 +787,7 @@ end_do_tag:
   }
   postponed_split = 0;          // don't split next time
   g_do_tagpreview = 0;          // don't do tag preview next time
-
-  return jumped_to_tag;
+  xfree(tofree);
 }
 
 // List all the matching tags.
@@ -696,15 +796,15 @@ static void print_tag_list(int new_tag, int use_tagstack, int num_matches, char
   taggy_T *tagstack = curwin->w_tagstack;
   int tagstackidx = curwin->w_tagstackidx;
   int i;
-  char_u *p;
-  char_u *command_end;
+  char *p;
+  char *command_end;
   tagptrs_T tagp;
   int taglen;
   int attr;
 
   // Assume that the first match indicates how long the tags can
   // be, and align the file names to that.
-  parse_match((char_u *)matches[0], &tagp);
+  parse_match(matches[0], &tagp);
   taglen = (int)(tagp.tagname_end - tagp.tagname + 2);
   if (taglen < 18) {
     taglen = 18;
@@ -722,7 +822,7 @@ static void print_tag_list(int new_tag, int use_tagstack, int num_matches, char
   msg_puts_attr(_("file\n"), HL_ATTR(HLF_T));
 
   for (i = 0; i < num_matches && !got_int; i++) {
-    parse_match((char_u *)matches[i], &tagp);
+    parse_match(matches[i], &tagp);
     if (!new_tag && (
                      (g_do_tagpreview != 0
                       && i == ptag_entry.cur_match)
@@ -732,10 +832,10 @@ static void print_tag_list(int new_tag, int use_tagstack, int num_matches, char
     } else {
       *IObuff = ' ';
     }
-    vim_snprintf((char *)IObuff + 1, IOSIZE - 1,
+    vim_snprintf(IObuff + 1, IOSIZE - 1,
                  "%2d %s ", i + 1,
                  mt_names[matches[i][0] & MT_MASK]);
-    msg_puts((char *)IObuff);
+    msg_puts(IObuff);
     if (tagp.tagkind != NULL) {
       msg_outtrans_len(tagp.tagkind,
                        (int)(tagp.tagkind_end - tagp.tagkind));
@@ -772,21 +872,21 @@ static void print_tag_list(int new_tag, int use_tagstack, int num_matches, char
         }
 
         // skip "file:" without a value (static tag)
-        if (STRNCMP(p, "file:", 5) == 0 && ascii_isspace(p[5])) {
+        if (strncmp(p, "file:", 5) == 0 && ascii_isspace(p[5])) {
           p += 5;
           continue;
         }
         // skip "kind:<kind>" and "<kind>"
         if (p == tagp.tagkind
             || (p + 5 == tagp.tagkind
-                && STRNCMP(p, "kind:", 5) == 0)) {
+                && strncmp(p, "kind:", 5) == 0)) {
           p = tagp.tagkind_end;
           continue;
         }
         // print all other extra fields
         attr = HL_ATTR(HLF_CM);
         while (*p && *p != '\r' && *p != '\n') {
-          if (msg_col + ptr2cells((char *)p) >= Columns) {
+          if (msg_col + ptr2cells(p) >= Columns) {
             msg_putchar('\n');
             if (got_int) {
               break;
@@ -832,7 +932,7 @@ static void print_tag_list(int new_tag, int use_tagstack, int num_matches, char
     }
 
     while (p != command_end) {
-      if (msg_col + (*p == TAB ? 1 : ptr2cells((char *)p)) > Columns) {
+      if (msg_col + (*p == TAB ? 1 : ptr2cells(p)) > Columns) {
         msg_putchar('\n');
       }
       if (got_int) {
@@ -877,14 +977,14 @@ static void print_tag_list(int new_tag, int use_tagstack, int num_matches, char
 
 /// Add the matching tags to the location list for the current
 /// window.
-static int add_llist_tags(char_u *tag, int num_matches, char **matches)
+static int add_llist_tags(char *tag, int num_matches, char **matches)
 {
   list_T *list;
-  char_u tag_name[128 + 1];
-  char_u *fname;
-  char_u *cmd;
+  char tag_name[128 + 1];
+  char *fname;
+  char *cmd;
   int i;
-  char_u *p;
+  char *p;
   tagptrs_T tagp;
 
   fname = xmalloc(MAXPATHL + 1);
@@ -896,14 +996,14 @@ static int add_llist_tags(char_u *tag, int num_matches, char **matches)
     long lnum;
     dict_T *dict;
 
-    parse_match((char_u *)matches[i], &tagp);
+    parse_match(matches[i], &tagp);
 
     // Save the tag name
     len = (int)(tagp.tagname_end - tagp.tagname);
     if (len > 128) {
       len = 128;
     }
-    STRLCPY(tag_name, tagp.tagname, len + 1);
+    xstrlcpy(tag_name, tagp.tagname, (size_t)len + 1);
     tag_name[len] = NUL;
 
     // Save the tag file name
@@ -911,17 +1011,17 @@ static int add_llist_tags(char_u *tag, int num_matches, char **matches)
     if (p == NULL) {
       continue;
     }
-    STRLCPY(fname, p, MAXPATHL);
+    xstrlcpy(fname, p, MAXPATHL);
     XFREE_CLEAR(p);
 
     // Get the line number or the search pattern used to locate
     // the tag.
     lnum = 0;
-    if (isdigit(*tagp.command)) {
+    if (isdigit((uint8_t)(*tagp.command))) {
       // Line number is used to locate the tag
-      lnum = atol((char *)tagp.command);
+      lnum = atol(tagp.command);
     } else {
-      char_u *cmd_start, *cmd_end;
+      char *cmd_start, *cmd_end;
 
       // Search pattern is used to locate the tag
 
@@ -969,7 +1069,7 @@ static int add_llist_tags(char_u *tag, int num_matches, char **matches)
       if (cmd_len > (CMDBUFFSIZE - 5)) {
         cmd_len = CMDBUFFSIZE - 5;
       }
-      snprintf((char *)cmd + len, (size_t)(CMDBUFFSIZE + 1 - len),
+      snprintf(cmd + len, (size_t)(CMDBUFFSIZE + 1 - len),
                "%.*s", cmd_len, cmd_start);
       len += cmd_len;
 
@@ -987,16 +1087,16 @@ static int add_llist_tags(char_u *tag, int num_matches, char **matches)
     dict = tv_dict_alloc();
     tv_list_append_dict(list, dict);
 
-    tv_dict_add_str(dict, S_LEN("text"), (const char *)tag_name);
+    tv_dict_add_str(dict, S_LEN("text"), tag_name);
     tv_dict_add_str(dict, S_LEN("filename"), (const char *)fname);
     tv_dict_add_nr(dict, S_LEN("lnum"), lnum);
     if (lnum == 0) {
-      tv_dict_add_str(dict, S_LEN("pattern"), (const char *)cmd);
+      tv_dict_add_str(dict, S_LEN("pattern"), cmd);
     }
   }
 
-  vim_snprintf((char *)IObuff, IOSIZE, "ltag %s", tag);
-  set_errorlist(curwin, list, ' ', (char *)IObuff, NULL);
+  vim_snprintf(IObuff, IOSIZE, "ltag %s", tag);
+  set_errorlist(curwin, list, ' ', IObuff, NULL);
 
   tv_list_free(list);
   XFREE_CLEAR(fname);
@@ -1005,9 +1105,7 @@ static int add_llist_tags(char_u *tag, int num_matches, char **matches)
   return OK;
 }
 
-/*
- * Free cached tags.
- */
+// Free cached tags.
 void tag_freematch(void)
 {
   XFREE_CLEAR(tagmatchname);
@@ -1023,20 +1121,18 @@ static void taglen_advance(int l)
   }
 }
 
-/*
- * Print the tag stack
- */
+// Print the tag stack
 void do_tags(exarg_T *eap)
 {
   int i;
-  char_u *name;
+  char *name;
   taggy_T *tagstack = curwin->w_tagstack;
   int tagstackidx = curwin->w_tagstackidx;
   int tagstacklen = curwin->w_tagstacklen;
 
   // Highlight title
   msg_puts_title(_("\n  # TO tag         FROM line  in file/text"));
-  for (i = 0; i < tagstacklen; ++i) {
+  for (i = 0; i < tagstacklen; i++) {
     if (tagstack[i].tagname != NULL) {
       name = fm_getname(&(tagstack[i].fmark), 30);
       if (name == NULL) {           // file name not available
@@ -1044,35 +1140,32 @@ void do_tags(exarg_T *eap)
       }
 
       msg_putchar('\n');
-      vim_snprintf((char *)IObuff, IOSIZE, "%c%2d %2d %-15s %5" PRIdLINENR "  ",
+      vim_snprintf(IObuff, IOSIZE, "%c%2d %2d %-15s %5" PRIdLINENR "  ",
                    i == tagstackidx ? '>' : ' ',
                    i + 1,
                    tagstack[i].cur_match + 1,
                    tagstack[i].tagname,
                    tagstack[i].fmark.mark.lnum);
-      msg_outtrans((char *)IObuff);
+      msg_outtrans(IObuff);
       msg_outtrans_attr(name, tagstack[i].fmark.fnum == curbuf->b_fnum
                         ? HL_ATTR(HLF_D) : 0);
       xfree(name);
     }
-    ui_flush();                    // show one line at a time
   }
   if (tagstackidx == tagstacklen) {     // idx at top of stack
     msg_puts("\n>");
   }
 }
 
-/*
- * Compare two strings, for length "len", ignoring case the ASCII way.
- * return 0 for match, < 0 for smaller, > 0 for bigger
- * Make sure case is folded to uppercase in comparison (like for 'sort -f')
- */
-static int tag_strnicmp(char_u *s1, char_u *s2, size_t len)
+// Compare two strings, for length "len", ignoring case the ASCII way.
+// return 0 for match, < 0 for smaller, > 0 for bigger
+// Make sure case is folded to uppercase in comparison (like for 'sort -f')
+static int tag_strnicmp(char *s1, char *s2, size_t len)
 {
   int i;
 
   while (len > 0) {
-    i = TOUPPER_ASC(*s1) - TOUPPER_ASC(*s2);
+    i = TOUPPER_ASC((uint8_t)(*s1)) - TOUPPER_ASC((uint8_t)(*s2));
     if (i != 0) {
       return i;                         // this character different
     }
@@ -1086,9 +1179,7 @@ static int tag_strnicmp(char_u *s1, char_u *s2, size_t len)
   return 0;                             // strings match
 }
 
-/*
- * Extract info from the tag search pattern "pats->pat".
- */
+// Extract info from the tag search pattern "pats->pat".
 static void prepare_pats(pat_T *pats, int has_re)
 {
   pats->head = pats->pat;
@@ -1105,7 +1196,8 @@ static void prepare_pats(pat_T *pats, int has_re)
       pats->headlen = 0;
     } else {
       for (pats->headlen = 0; pats->head[pats->headlen] != NUL; pats->headlen++) {
-        if (vim_strchr((p_magic ? ".[~*\\$" : "\\$"), pats->head[pats->headlen]) != NULL) {
+        if (vim_strchr(magic_isset() ? ".[~*\\$" : "\\$",
+                       (uint8_t)pats->head[pats->headlen]) != NULL) {
           break;
         }
       }
@@ -1116,7 +1208,7 @@ static void prepare_pats(pat_T *pats, int has_re)
   }
 
   if (has_re) {
-    pats->regmatch.regprog = vim_regcomp((char *)pats->pat, p_magic ? RE_MAGIC : 0);
+    pats->regmatch.regprog = vim_regcomp(pats->pat, magic_isset() ? RE_MAGIC : 0);
   } else {
     pats->regmatch.regprog = NULL;
   }
@@ -1133,8 +1225,7 @@ static void prepare_pats(pat_T *pats, int has_re)
 /// @param match_count  here the number of tags found will be placed
 /// @param flags  flags from find_tags (TAG_*)
 /// @param buf_ffname  name of buffer for priority
-static int find_tagfunc_tags(char_u *pat, garray_T *ga, int *match_count, int flags,
-                             char_u *buf_ffname)
+static int find_tagfunc_tags(char *pat, garray_T *ga, int *match_count, int flags, char *buf_ffname)
 {
   pos_T save_pos;
   list_T *taglist;
@@ -1142,7 +1233,7 @@ static int find_tagfunc_tags(char_u *pat, garray_T *ga, int *match_count, int fl
   int result = FAIL;
   typval_T args[4];
   typval_T rettv;
-  char_u flagString[4];
+  char flagString[4];
   taggy_T *tag = NULL;
 
   if (curwin->w_tagstacklen > 0) {
@@ -1153,14 +1244,14 @@ static int find_tagfunc_tags(char_u *pat, garray_T *ga, int *match_count, int fl
     }
   }
 
-  if (*curbuf->b_p_tfu == NUL) {
+  if (*curbuf->b_p_tfu == NUL || curbuf->b_tfu_cb.type == kCallbackNone) {
     return FAIL;
   }
 
   args[0].v_type = VAR_STRING;
-  args[0].vval.v_string = (char *)pat;
+  args[0].vval.v_string = pat;
   args[1].v_type = VAR_STRING;
-  args[1].vval.v_string = (char *)flagString;
+  args[1].vval.v_string = flagString;
 
   // create 'info' dict argument
   dict_T *const d = tv_dict_alloc_lock(VAR_FIXED);
@@ -1177,14 +1268,14 @@ static int find_tagfunc_tags(char_u *pat, garray_T *ga, int *match_count, int fl
 
   args[3].v_type = VAR_UNKNOWN;
 
-  vim_snprintf((char *)flagString, sizeof(flagString),
+  vim_snprintf(flagString, sizeof(flagString),
                "%s%s%s",
                g_tag_at_cursor      ? "c": "",
                flags & TAG_INS_COMP ? "i": "",
                flags & TAG_REGEXP   ? "r": "");
 
   save_pos = curwin->w_cursor;
-  result = call_vim_function((char *)curbuf->b_p_tfu, 3, args, &rettv);
+  result = callback_call(&curbuf->b_tfu_cb, 3, args, &rettv);
   curwin->w_cursor = save_pos;  // restore the cursor position
   d->dv_refcount--;
 
@@ -1203,10 +1294,10 @@ static int find_tagfunc_tags(char_u *pat, garray_T *ga, int *match_count, int fl
   taglist = rettv.vval.v_list;
 
   TV_LIST_ITER_CONST(taglist, li, {
-    char_u *res_name;
-    char_u *res_fname;
-    char_u *res_cmd;
-    char_u *res_kind;
+    char *res_name;
+    char *res_fname;
+    char *res_cmd;
+    char *res_kind;
     int has_extra = 0;
     int name_only = flags & TAG_NAMES;
 
@@ -1222,34 +1313,34 @@ static int find_tagfunc_tags(char_u *pat, garray_T *ga, int *match_count, int fl
     res_kind = NULL;
 
     TV_DICT_ITER(TV_LIST_ITEM_TV(li)->vval.v_dict, di, {
-      const char_u *dict_key = di->di_key;
+      const char *dict_key = (char *)di->di_key;
       typval_T *tv = &di->di_tv;
 
       if (tv->v_type != VAR_STRING || tv->vval.v_string == NULL) {
         continue;
       }
 
-      len += STRLEN(tv->vval.v_string) + 1;   // Space for "\tVALUE"
-      if (!STRCMP(dict_key, "name")) {
-        res_name = (char_u *)tv->vval.v_string;
+      len += strlen(tv->vval.v_string) + 1;   // Space for "\tVALUE"
+      if (!strcmp(dict_key, "name")) {
+        res_name = tv->vval.v_string;
         continue;
       }
-      if (!STRCMP(dict_key, "filename")) {
-        res_fname = (char_u *)tv->vval.v_string;
+      if (!strcmp(dict_key, "filename")) {
+        res_fname = tv->vval.v_string;
         continue;
       }
-      if (!STRCMP(dict_key, "cmd")) {
-        res_cmd = (char_u *)tv->vval.v_string;
+      if (!strcmp(dict_key, "cmd")) {
+        res_cmd = tv->vval.v_string;
         continue;
       }
       has_extra = 1;
-      if (!STRCMP(dict_key, "kind")) {
-        res_kind = (char_u *)tv->vval.v_string;
+      if (!strcmp(dict_key, "kind")) {
+        res_kind = tv->vval.v_string;
         continue;
       }
       // Other elements will be stored as "\tKEY:VALUE"
       // Allocate space for the key and the colon
-      len += STRLEN(dict_key) + 1;
+      len += strlen(dict_key) + 1;
     });
 
     if (has_extra) {
@@ -1261,62 +1352,62 @@ static int find_tagfunc_tags(char_u *pat, garray_T *ga, int *match_count, int fl
       break;
     }
 
-    char_u *const mfp = name_only ? vim_strsave(res_name) : xmalloc(len + 2);
+    char *const mfp = name_only ? xstrdup(res_name) : xmalloc(len + 2);
 
     if (!name_only) {
-      char_u *p = mfp;
+      char *p = mfp;
 
       *p++ = MT_GL_OTH + 1;   // mtt
       *p++ = TAG_SEP;     // no tag file name
 
       STRCPY(p, res_name);
-      p += STRLEN(p);
+      p += strlen(p);
 
       *p++ = TAB;
       STRCPY(p, res_fname);
-      p += STRLEN(p);
+      p += strlen(p);
 
       *p++ = TAB;
       STRCPY(p, res_cmd);
-      p += STRLEN(p);
+      p += strlen(p);
 
       if (has_extra) {
         STRCPY(p, ";\"");
-        p += STRLEN(p);
+        p += strlen(p);
 
         if (res_kind) {
           *p++ = TAB;
           STRCPY(p, res_kind);
-          p += STRLEN(p);
+          p += strlen(p);
         }
 
         TV_DICT_ITER(TV_LIST_ITEM_TV(li)->vval.v_dict, di, {
-          const char_u *dict_key = di->di_key;
+          const char *dict_key = (char *)di->di_key;
           typval_T *tv = &di->di_tv;
           if (tv->v_type != VAR_STRING || tv->vval.v_string == NULL) {
             continue;
           }
 
-          if (!STRCMP(dict_key, "name")) {
+          if (!strcmp(dict_key, "name")) {
             continue;
           }
-          if (!STRCMP(dict_key, "filename")) {
+          if (!strcmp(dict_key, "filename")) {
             continue;
           }
-          if (!STRCMP(dict_key, "cmd")) {
+          if (!strcmp(dict_key, "cmd")) {
             continue;
           }
-          if (!STRCMP(dict_key, "kind")) {
+          if (!strcmp(dict_key, "kind")) {
             continue;
           }
 
           *p++ = TAB;
           STRCPY(p, dict_key);
-          p += STRLEN(p);
+          p += strlen(p);
           STRCPY(p, ":");
-          p += STRLEN(p);
+          p += strlen(p);
           STRCPY(p, tv->vval.v_string);
-          p += STRLEN(p);
+          p += strlen(p);
         });
       }
     }
@@ -1334,6 +1425,873 @@ static int find_tagfunc_tags(char_u *pat, garray_T *ga, int *match_count, int fl
   return result;
 }
 
+/// Initialize the state used by find_tags()
+static void findtags_state_init(findtags_state_T *st, char *pat, int flags, int mincount)
+{
+  st->tag_fname = xmalloc(MAXPATHL + 1);
+  st->fp = NULL;
+  st->orgpat = xmalloc(sizeof(pat_T));
+  st->orgpat->pat = pat;
+  st->orgpat->len = (int)strlen(pat);
+  st->orgpat->regmatch.regprog = NULL;
+  st->flags = flags;
+  st->tag_file_sorted = NUL;
+  st->help_lang_find = NULL;
+  st->is_txt = false;
+  st->did_open = false;
+  st->help_only = (flags & TAG_HELP);
+  st->get_searchpat = false;
+  st->help_lang[0] = NUL;
+  st->help_pri = 0;
+  st->mincount = mincount;
+  st->lbuf_size = LSIZE;
+  st->lbuf = xmalloc((size_t)st->lbuf_size);
+  st->match_count = 0;
+  st->stop_searching = false;
+
+  for (int mtt = 0; mtt < MT_COUNT; mtt++) {
+    ga_init(&st->ga_match[mtt], sizeof(char *), 100);
+    hash_init(&st->ht_match[mtt]);
+  }
+}
+
+/// Free the state used by find_tags()
+static void findtags_state_free(findtags_state_T *st)
+{
+  xfree(st->tag_fname);
+  xfree(st->lbuf);
+  vim_regfree(st->orgpat->regmatch.regprog);
+  xfree(st->orgpat);
+}
+
+/// Initialize the language and priority used for searching tags in a Vim help
+/// file.
+/// Returns true to process the help file for tags and false to skip the file.
+static bool findtags_in_help_init(findtags_state_T *st)
+{
+  int i;
+
+  // Keep "en" as the language if the file extension is ".txt"
+  if (st->is_txt) {
+    STRCPY(st->help_lang, "en");
+  } else {
+    // Prefer help tags according to 'helplang'.  Put the two-letter
+    // language name in help_lang[].
+    i = (int)strlen(st->tag_fname);
+    if (i > 3 && st->tag_fname[i - 3] == '-') {
+      xstrlcpy(st->help_lang, st->tag_fname + i - 2, 3);
+    } else {
+      STRCPY(st->help_lang, "en");
+    }
+  }
+  // When searching for a specific language skip tags files for other
+  // languages.
+  if (st->help_lang_find != NULL
+      && STRICMP(st->help_lang, st->help_lang_find) != 0) {
+    return false;
+  }
+
+  // For CTRL-] in a help file prefer a match with the same language.
+  if ((st->flags & TAG_KEEP_LANG)
+      && st->help_lang_find == NULL
+      && curbuf->b_fname != NULL
+      && (i = (int)strlen(curbuf->b_fname)) > 4
+      && curbuf->b_fname[i - 1] == 'x'
+      && curbuf->b_fname[i - 4] == '.'
+      && STRNICMP(curbuf->b_fname + i - 3, st->help_lang, 2) == 0) {
+    st->help_pri = 0;
+  } else {
+    st->help_pri = 1;
+    char *s;
+    for (s = p_hlg; *s != NUL; s++) {
+      if (STRNICMP(s, st->help_lang, 2) == 0) {
+        break;
+      }
+      st->help_pri++;
+      if ((s = vim_strchr(s, ',')) == NULL) {
+        break;
+      }
+    }
+    if (s == NULL || *s == NUL) {
+      // Language not in 'helplang': use last, prefer English, unless
+      // found already.
+      st->help_pri++;
+      if (STRICMP(st->help_lang, "en") != 0) {
+        st->help_pri++;
+      }
+    }
+  }
+
+  return true;
+}
+
+/// Use the function set in 'tagfunc' (if configured and enabled) to get the
+/// tags.
+/// Return OK if at least 1 tag has been successfully found, NOTDONE if the
+/// 'tagfunc' is not used or the 'tagfunc' returns v:null and FAIL otherwise.
+static int findtags_apply_tfu(findtags_state_T *st, char *pat, char *buf_ffname)
+{
+  const bool use_tfu = ((st->flags & TAG_NO_TAGFUNC) == 0);
+
+  if (!use_tfu || tfu_in_use || *curbuf->b_p_tfu == NUL) {
+    return NOTDONE;
+  }
+
+  tfu_in_use = true;
+  int retval = find_tagfunc_tags(pat, st->ga_match, &st->match_count,
+                                 st->flags, buf_ffname);
+  tfu_in_use = false;
+
+  return retval;
+}
+
+/// Read the next line from a tags file.
+/// Returns TAGS_READ_SUCCESS if a tags line is successfully read and should be
+/// processed.
+/// Returns TAGS_READ_EOF if the end of file is reached.
+/// Returns TAGS_READ_IGNORE if the current line should be ignored (used when
+/// reached end of a emacs included tags file)
+static tags_read_status_T findtags_get_next_line(findtags_state_T *st, tagsearch_info_T *sinfo_p)
+{
+  int eof;
+  off_T offset;
+
+  // For binary search: compute the next offset to use.
+  if (st->state == TS_BINARY) {
+    offset = sinfo_p->low_offset + ((sinfo_p->high_offset - sinfo_p->low_offset) / 2);
+    if (offset == sinfo_p->curr_offset) {
+      return TAGS_READ_EOF;  // End the binary search without a match.
+    } else {
+      sinfo_p->curr_offset = offset;
+    }
+  } else if (st->state == TS_SKIP_BACK) {
+    // Skipping back (after a match during binary search).
+    sinfo_p->curr_offset -= st->lbuf_size * 2;
+    if (sinfo_p->curr_offset < 0) {
+      sinfo_p->curr_offset = 0;
+      rewind(st->fp);
+      st->state = TS_STEP_FORWARD;
+    }
+  }
+
+  // When jumping around in the file, first read a line to find the
+  // start of the next line.
+  if (st->state == TS_BINARY || st->state == TS_SKIP_BACK) {
+    // Adjust the search file offset to the correct position
+    sinfo_p->curr_offset_used = sinfo_p->curr_offset;
+    vim_ignored = vim_fseek(st->fp, sinfo_p->curr_offset, SEEK_SET);
+    eof = vim_fgets(st->lbuf, st->lbuf_size, st->fp);
+    if (!eof && sinfo_p->curr_offset != 0) {
+      sinfo_p->curr_offset = vim_ftell(st->fp);
+      if (sinfo_p->curr_offset == sinfo_p->high_offset) {
+        // oops, gone a bit too far; try from low offset
+        vim_ignored = vim_fseek(st->fp, sinfo_p->low_offset, SEEK_SET);
+        sinfo_p->curr_offset = sinfo_p->low_offset;
+      }
+      eof = vim_fgets(st->lbuf, st->lbuf_size, st->fp);
+    }
+    // skip empty and blank lines
+    while (!eof && vim_isblankline(st->lbuf)) {
+      sinfo_p->curr_offset = vim_ftell(st->fp);
+      eof = vim_fgets(st->lbuf, st->lbuf_size, st->fp);
+    }
+    if (eof) {
+      // Hit end of file.  Skip backwards.
+      st->state = TS_SKIP_BACK;
+      sinfo_p->match_offset = vim_ftell(st->fp);
+      sinfo_p->curr_offset = sinfo_p->curr_offset_used;
+      return TAGS_READ_IGNORE;
+    }
+  } else {
+    // Not jumping around in the file: Read the next line.
+
+    // skip empty and blank lines
+    do {
+      eof = vim_fgets(st->lbuf, st->lbuf_size, st->fp);
+    } while (!eof && vim_isblankline(st->lbuf));
+
+    if (eof) {
+      return TAGS_READ_EOF;
+    }
+  }
+
+  return TAGS_READ_SUCCESS;
+}
+
+/// Parse a tags file header line in "st->lbuf".
+/// Returns true if the current line in st->lbuf is not a tags header line and
+/// should be parsed as a regular tag line. Returns false if the line is a
+/// header line and the next header line should be read.
+static bool findtags_hdr_parse(findtags_state_T *st)
+{
+  // Header lines in a tags file start with "!_TAG_"
+  if (strncmp(st->lbuf, "!_TAG_", 6) != 0) {
+    // Non-header item before the header, e.g. "!" itself.
+    return true;
+  }
+
+  // Process the header line.
+  if (strncmp(st->lbuf, "!_TAG_FILE_SORTED\t", 18) == 0) {
+    st->tag_file_sorted = (uint8_t)st->lbuf[18];
+  }
+  if (strncmp(st->lbuf, "!_TAG_FILE_ENCODING\t", 20) == 0) {
+    // Prepare to convert every line from the specified encoding to
+    // 'encoding'.
+    char *p;
+    for (p = st->lbuf + 20; *p > ' ' && *p < 127; p++) {}
+    *p = NUL;
+    convert_setup(&st->vimconv, st->lbuf + 20, p_enc);
+  }
+
+  // Read the next line.  Unrecognized flags are ignored.
+  return false;
+}
+
+/// Handler to initialize the state when starting to process a new tags file.
+/// Called in the TS_START state when finding tags from a tags file.
+/// Returns true if the line read from the tags file should be parsed and
+/// false if the line should be ignored.
+static bool findtags_start_state_handler(findtags_state_T *st, bool *sortic,
+                                         tagsearch_info_T *sinfo_p)
+{
+  const bool noic = (st->flags & TAG_NOIC);
+
+  // The header ends when the line sorts below "!_TAG_".  When case is
+  // folded lower case letters sort before "_".
+  if (strncmp(st->lbuf, "!_TAG_", 6) <= 0
+      || (st->lbuf[0] == '!' && ASCII_ISLOWER(st->lbuf[1]))) {
+    return findtags_hdr_parse(st);
+  }
+
+  // Headers ends.
+
+  // When there is no tag head, or ignoring case, need to do a
+  // linear search.
+  // When no "!_TAG_" is found, default to binary search.  If
+  // the tag file isn't sorted, the second loop will find it.
+  // When "!_TAG_FILE_SORTED" found: start binary search if
+  // flag set.
+  if (st->linear) {
+    st->state = TS_LINEAR;
+  } else if (st->tag_file_sorted == NUL) {
+    st->state = TS_BINARY;
+  } else if (st->tag_file_sorted == '1') {
+    st->state = TS_BINARY;
+  } else if (st->tag_file_sorted == '2') {
+    st->state = TS_BINARY;
+    *sortic = true;
+    st->orgpat->regmatch.rm_ic = (p_ic || !noic);
+  } else {
+    st->state = TS_LINEAR;
+  }
+
+  if (st->state == TS_BINARY && st->orgpat->regmatch.rm_ic && !*sortic) {
+    // Binary search won't work for ignoring case, use linear
+    // search.
+    st->linear = true;
+    st->state = TS_LINEAR;
+  }
+
+  // When starting a binary search, get the size of the file and
+  // compute the first offset.
+  if (st->state == TS_BINARY) {
+    if (vim_fseek(st->fp, 0, SEEK_END) != 0) {
+      // can't seek, don't use binary search
+      st->state = TS_LINEAR;
+    } else {
+      // Get the tag file size.
+      // Don't use lseek(), it doesn't work
+      // properly on MacOS Catalina.
+      const off_T filesize = vim_ftell(st->fp);
+      vim_ignored = vim_fseek(st->fp, 0, SEEK_SET);
+
+      // Calculate the first read offset in the file.  Start
+      // the search in the middle of the file.
+      sinfo_p->low_offset = 0;
+      sinfo_p->low_char = 0;
+      sinfo_p->high_offset = filesize;
+      sinfo_p->curr_offset = 0;
+      sinfo_p->high_char = 0xff;
+    }
+    return false;
+  }
+
+  return true;
+}
+
+/// Parse a tag line read from a tags file.
+/// Also compares the tag name in "tagpp->tagname" with a search pattern in
+/// "st->orgpat->head" as a quick check if the tag may match.
+/// Returns:
+/// - TAG_MATCH_SUCCESS if the tag may match
+/// - TAG_MATCH_FAIL if the tag doesn't match
+/// - TAG_MATCH_NEXT to look for the next matching tag (used in a binary search)
+/// - TAG_MATCH_STOP if all the tags are processed without a match.
+/// Uses the values in "margs" for doing the comparison.
+static tagmatch_status_T findtags_parse_line(findtags_state_T *st, tagptrs_T *tagpp,
+                                             findtags_match_args_T *margs,
+                                             tagsearch_info_T *sinfo_p)
+{
+  int status;
+  int i;
+  int cmplen;
+  int tagcmp;
+
+  // Figure out where the different strings are in this line.
+  // For "normal" tags: Do a quick check if the tag matches.
+  // This speeds up tag searching a lot!
+  if (st->orgpat->headlen) {
+    CLEAR_FIELD(*tagpp);
+    tagpp->tagname = st->lbuf;
+    tagpp->tagname_end = vim_strchr(st->lbuf, TAB);
+    if (tagpp->tagname_end == NULL) {
+      // Corrupted tag line.
+      return TAG_MATCH_FAIL;
+    }
+
+    // Skip this line if the length of the tag is different and
+    // there is no regexp, or the tag is too short.
+    cmplen = (int)(tagpp->tagname_end - tagpp->tagname);
+    if (p_tl != 0 && cmplen > p_tl) {  // adjust for 'taglength'
+      cmplen = (int)p_tl;
+    }
+    if ((st->flags & TAG_REGEXP) && st->orgpat->headlen < cmplen) {
+      cmplen = st->orgpat->headlen;
+    } else if (st->state == TS_LINEAR && st->orgpat->headlen != cmplen) {
+      return TAG_MATCH_NEXT;
+    }
+
+    if (st->state == TS_BINARY) {
+      // Simplistic check for unsorted tags file.
+      i = (int)tagpp->tagname[0];
+      if (margs->sortic) {
+        i = TOUPPER_ASC(tagpp->tagname[0]);
+      }
+      if (i < sinfo_p->low_char || i > sinfo_p->high_char) {
+        margs->sort_error = true;
+      }
+
+      // Compare the current tag with the searched tag.
+      if (margs->sortic) {
+        tagcmp = tag_strnicmp(tagpp->tagname, st->orgpat->head,
+                              (size_t)cmplen);
+      } else {
+        tagcmp = strncmp(tagpp->tagname, st->orgpat->head, (size_t)cmplen);
+      }
+
+      // A match with a shorter tag means to search forward.
+      // A match with a longer tag means to search backward.
+      if (tagcmp == 0) {
+        if (cmplen < st->orgpat->headlen) {
+          tagcmp = -1;
+        } else if (cmplen > st->orgpat->headlen) {
+          tagcmp = 1;
+        }
+      }
+
+      if (tagcmp == 0) {
+        // We've located the tag, now skip back and search
+        // forward until the first matching tag is found.
+        st->state = TS_SKIP_BACK;
+        sinfo_p->match_offset = sinfo_p->curr_offset;
+        return TAG_MATCH_NEXT;
+      }
+      if (tagcmp < 0) {
+        sinfo_p->curr_offset = vim_ftell(st->fp);
+        if (sinfo_p->curr_offset < sinfo_p->high_offset) {
+          sinfo_p->low_offset = sinfo_p->curr_offset;
+          if (margs->sortic) {
+            sinfo_p->low_char = TOUPPER_ASC(tagpp->tagname[0]);
+          } else {
+            sinfo_p->low_char = (uint8_t)tagpp->tagname[0];
+          }
+          return TAG_MATCH_NEXT;
+        }
+      }
+      if (tagcmp > 0 && sinfo_p->curr_offset != sinfo_p->high_offset) {
+        sinfo_p->high_offset = sinfo_p->curr_offset;
+        if (margs->sortic) {
+          sinfo_p->high_char = TOUPPER_ASC(tagpp->tagname[0]);
+        } else {
+          sinfo_p->high_char = (uint8_t)tagpp->tagname[0];
+        }
+        return TAG_MATCH_NEXT;
+      }
+
+      // No match yet and are at the end of the binary search.
+      return TAG_MATCH_STOP;
+    } else if (st->state == TS_SKIP_BACK) {
+      assert(cmplen >= 0);
+      if (mb_strnicmp(tagpp->tagname, st->orgpat->head, (size_t)cmplen) != 0) {
+        st->state = TS_STEP_FORWARD;
+      } else {
+        // Have to skip back more.  Restore the curr_offset
+        // used, otherwise we get stuck at a long line.
+        sinfo_p->curr_offset = sinfo_p->curr_offset_used;
+      }
+      return TAG_MATCH_NEXT;
+    } else if (st->state == TS_STEP_FORWARD) {
+      assert(cmplen >= 0);
+      if (mb_strnicmp(tagpp->tagname, st->orgpat->head, (size_t)cmplen) != 0) {
+        if ((off_T)vim_ftell(st->fp) > sinfo_p->match_offset) {
+          return TAG_MATCH_STOP;      // past last match
+        } else {
+          return TAG_MATCH_NEXT;      // before first match
+        }
+      }
+    } else {
+      // skip this match if it can't match
+      assert(cmplen >= 0);
+      if (mb_strnicmp(tagpp->tagname, st->orgpat->head, (size_t)cmplen) != 0) {
+        return TAG_MATCH_NEXT;
+      }
+    }
+
+    // Can be a matching tag, isolate the file name and command.
+    tagpp->fname = tagpp->tagname_end + 1;
+    tagpp->fname_end = vim_strchr(tagpp->fname, TAB);
+    if (tagpp->fname_end == NULL) {
+      status = FAIL;
+    } else {
+      tagpp->command = tagpp->fname_end + 1;
+      status = OK;
+    }
+  } else {
+    status = parse_tag_line(st->lbuf, tagpp);
+  }
+
+  if (status == FAIL) {
+    return TAG_MATCH_FAIL;
+  }
+
+  return TAG_MATCH_SUCCESS;
+}
+
+/// Initialize the structure used for tag matching.
+static void findtags_matchargs_init(findtags_match_args_T *margs, int flags)
+{
+  margs->matchoff = 0;                        // match offset
+  margs->match_re = false;                    // match with regexp
+  margs->match_no_ic = false;                 // matches with case
+  margs->has_re = (flags & TAG_REGEXP);       // regexp used
+  margs->sortic = false;                      // tag file sorted in nocase
+  margs->sort_error = false;                  // tags file not sorted
+}
+
+/// Compares the tag name in "tagpp->tagname" with a search pattern in
+/// "st->orgpat->pat".
+/// Returns true if the tag matches, false if the tag doesn't match.
+/// Uses the values in "margs" for doing the comparison.
+static bool findtags_match_tag(findtags_state_T *st, tagptrs_T *tagpp, findtags_match_args_T *margs)
+{
+  bool match = false;
+
+  // First try matching with the pattern literally (also when it is
+  // a regexp).
+  int cmplen = (int)(tagpp->tagname_end - tagpp->tagname);
+  if (p_tl != 0 && cmplen > p_tl) {           // adjust for 'taglength'
+    cmplen = (int)p_tl;
+  }
+  // if tag length does not match, don't try comparing
+  if (st->orgpat->len != cmplen) {
+    match = false;
+  } else {
+    if (st->orgpat->regmatch.rm_ic) {
+      assert(cmplen >= 0);
+      match = mb_strnicmp(tagpp->tagname, st->orgpat->pat, (size_t)cmplen) == 0;
+      if (match) {
+        margs->match_no_ic = strncmp(tagpp->tagname, st->orgpat->pat, (size_t)cmplen) == 0;
+      }
+    } else {
+      match = strncmp(tagpp->tagname, st->orgpat->pat, (size_t)cmplen) == 0;
+    }
+  }
+
+  // Has a regexp: Also find tags matching regexp.
+  margs->match_re = false;
+  if (!match && st->orgpat->regmatch.regprog != NULL) {
+    char cc = *tagpp->tagname_end;
+    *tagpp->tagname_end = NUL;
+    match = vim_regexec(&st->orgpat->regmatch, tagpp->tagname, (colnr_T)0);
+    if (match) {
+      margs->matchoff = (int)(st->orgpat->regmatch.startp[0] - tagpp->tagname);
+      if (st->orgpat->regmatch.rm_ic) {
+        st->orgpat->regmatch.rm_ic = false;
+        margs->match_no_ic = vim_regexec(&st->orgpat->regmatch,
+                                         tagpp->tagname, (colnr_T)0);
+        st->orgpat->regmatch.rm_ic = true;
+      }
+    }
+    *tagpp->tagname_end = cc;
+    margs->match_re = true;
+  }
+
+  return match;
+}
+
+/// Convert the encoding of a line read from a tags file in "st->lbuf".
+/// Converting the pattern from 'enc' to the tags file encoding doesn't work,
+/// because characters are not recognized. The converted line is saved in
+/// st->lbuf.
+static void findtags_string_convert(findtags_state_T *st)
+{
+  char *conv_line = string_convert(&st->vimconv, st->lbuf, NULL);
+  if (conv_line == NULL) {
+    return;
+  }
+
+  // Copy or swap lbuf and conv_line.
+  int len = (int)strlen(conv_line) + 1;
+  if (len > st->lbuf_size) {
+    xfree(st->lbuf);
+    st->lbuf = conv_line;
+    st->lbuf_size = len;
+  } else {
+    STRCPY(st->lbuf, conv_line);
+    xfree(conv_line);
+  }
+}
+
+/// Add a matching tag found in a tags file to st->ht_match and st->ga_match.
+static void findtags_add_match(findtags_state_T *st, tagptrs_T *tagpp, findtags_match_args_T *margs,
+                               char *buf_ffname, hash_T *hash)
+{
+  const bool name_only = (st->flags & TAG_NAMES);
+  int mtt;
+  size_t len = 0;
+  bool is_current;             // file name matches
+  bool is_static;              // current tag line is static
+  char *mfp;
+  char *p;
+  char *s;
+
+  // Decide in which array to store this match.
+  is_current = test_for_current(tagpp->fname, tagpp->fname_end,
+                                st->tag_fname, buf_ffname);
+  is_static = test_for_static(tagpp);
+
+  // Decide in which of the sixteen tables to store this match.
+  if (is_static) {
+    if (is_current) {
+      mtt = MT_ST_CUR;
+    } else {
+      mtt = MT_ST_OTH;
+    }
+  } else {
+    if (is_current) {
+      mtt = MT_GL_CUR;
+    } else {
+      mtt = MT_GL_OTH;
+    }
+  }
+  if (st->orgpat->regmatch.rm_ic && !margs->match_no_ic) {
+    mtt += MT_IC_OFF;
+  }
+  if (margs->match_re) {
+    mtt += MT_RE_OFF;
+  }
+
+  // Add the found match in ht_match[mtt] and ga_match[mtt].
+  // Store the info we need later, which depends on the kind of
+  // tags we are dealing with.
+  if (st->help_only) {
+#define ML_EXTRA 3
+    // Append the help-heuristic number after the tagname, for
+    // sorting it later.  The heuristic is ignored for
+    // detecting duplicates.
+    // The format is {tagname}@{lang}NUL{heuristic}NUL
+    *tagpp->tagname_end = NUL;
+    len = (size_t)(tagpp->tagname_end - tagpp->tagname);
+    mfp = xmalloc(sizeof(char) + len + 10 + ML_EXTRA + 1);
+
+    p = mfp;
+    STRCPY(p, tagpp->tagname);
+    p[len] = '@';
+    STRCPY(p + len + 1, st->help_lang);
+    snprintf(p + len + 1 + ML_EXTRA, strlen(p) + len + 1 + ML_EXTRA, "%06d",
+             help_heuristic(tagpp->tagname,
+                            margs->match_re ? margs->matchoff : 0,
+                            !margs->match_no_ic) + st->help_pri);
+
+    *tagpp->tagname_end = TAB;
+  } else if (name_only) {
+    if (st->get_searchpat) {
+      char *temp_end = tagpp->command;
+
+      if (*temp_end == '/') {
+        while (*temp_end && *temp_end != '\r'
+               && *temp_end != '\n'
+               && *temp_end != '$') {
+          temp_end++;
+        }
+      }
+
+      if (tagpp->command + 2 < temp_end) {
+        len = (size_t)(temp_end - tagpp->command - 2);
+        mfp = xmalloc(len + 2);
+        xstrlcpy(mfp, tagpp->command + 2, len + 1);
+      } else {
+        mfp = NULL;
+      }
+      st->get_searchpat = false;
+    } else {
+      len = (size_t)(tagpp->tagname_end - tagpp->tagname);
+      mfp = xmalloc(sizeof(char) + len + 1);
+      xstrlcpy(mfp, tagpp->tagname, len + 1);
+
+      // if wanted, re-read line to get long form too
+      if (State & MODE_INSERT) {
+        st->get_searchpat = p_sft;
+      }
+    }
+  } else {
+    size_t tag_fname_len = strlen(st->tag_fname);
+    // Save the tag in a buffer.
+    // Use 0x02 to separate fields (Can't use NUL, because the
+    // hash key is terminated by NUL).
+    // Emacs tag: <mtt><tag_fname><0x02><ebuf><0x02><lbuf><NUL>
+    // other tag: <mtt><tag_fname><0x02><0x02><lbuf><NUL>
+    // without Emacs tags: <mtt><tag_fname><0x02><lbuf><NUL>
+    // Here <mtt> is the "mtt" value plus 1 to avoid NUL.
+    len = tag_fname_len + strlen(st->lbuf) + 3;
+    mfp = xmalloc(sizeof(char) + len + 1);
+    p = mfp;
+    p[0] = (char)(mtt + 1);
+    STRCPY(p + 1, st->tag_fname);
+#ifdef BACKSLASH_IN_FILENAME
+    // Ignore differences in slashes, avoid adding
+    // both path/file and path\file.
+    slash_adjust(p + 1);
+#endif
+    p[tag_fname_len + 1] = TAG_SEP;
+    s = p + 1 + tag_fname_len + 1;
+    STRCPY(s, st->lbuf);
+  }
+
+  if (mfp != NULL) {
+    hashitem_T *hi;
+
+    // Don't add identical matches.
+    // "mfp" is used as a hash key, there is a NUL byte to end
+    // the part that matters for comparing, more bytes may
+    // follow after it.  E.g. help tags store the priority
+    // after the NUL.
+    *hash = hash_hash(mfp);
+    hi = hash_lookup(&st->ht_match[mtt], (const char *)mfp, strlen(mfp), *hash);
+    if (HASHITEM_EMPTY(hi)) {
+      hash_add_item(&st->ht_match[mtt], hi, mfp, *hash);
+      GA_APPEND(char *, &st->ga_match[mtt], mfp);
+      st->match_count++;
+    } else {
+      // duplicate tag, drop it
+      xfree(mfp);
+    }
+  }
+}
+
+/// Read and get all the tags from file st->tag_fname.
+/// Sets "st->stop_searching" to true to stop searching for additional tags.
+static void findtags_get_all_tags(findtags_state_T *st, findtags_match_args_T *margs,
+                                  char *buf_ffname)
+{
+  tagptrs_T tagp;
+  tagsearch_info_T search_info;
+  int retval;
+  hash_T hash = 0;
+
+  // This is only to avoid a compiler warning for using search_info
+  // uninitialised.
+  CLEAR_FIELD(search_info);
+
+  // Read and parse the lines in the file one by one
+  for (;;) {
+    // check for CTRL-C typed, more often when jumping around
+    if (st->state == TS_BINARY || st->state == TS_SKIP_BACK) {
+      line_breakcheck();
+    } else {
+      fast_breakcheck();
+    }
+    if ((st->flags & TAG_INS_COMP)) {   // Double brackets for gcc
+      ins_compl_check_keys(30, false);
+    }
+    if (got_int || ins_compl_interrupted()) {
+      st->stop_searching = true;
+      break;
+    }
+    // When mincount is TAG_MANY, stop when enough matches have been
+    // found (for completion).
+    if (st->mincount == TAG_MANY && st->match_count >= TAG_MANY) {
+      st->stop_searching = true;
+      break;
+    }
+    if (st->get_searchpat) {
+      goto line_read_in;
+    }
+
+    retval = (int)findtags_get_next_line(st, &search_info);
+    if (retval == TAGS_READ_IGNORE) {
+      continue;
+    }
+    if (retval == TAGS_READ_EOF) {
+      break;
+    }
+
+line_read_in:
+
+    if (st->vimconv.vc_type != CONV_NONE) {
+      findtags_string_convert(st);
+    }
+
+    // When still at the start of the file, check for Emacs tags file
+    // format, and for "not sorted" flag.
+    if (st->state == TS_START) {
+      if (!findtags_start_state_handler(st, &margs->sortic, &search_info)) {
+        continue;
+      }
+    }
+
+    // When the line is too long the NUL will not be in the
+    // last-but-one byte (see vim_fgets()).
+    // Has been reported for Mozilla JS with extremely long names.
+    // In that case we need to increase lbuf_size.
+    if (st->lbuf[st->lbuf_size - 2] != NUL) {
+      st->lbuf_size *= 2;
+      xfree(st->lbuf);
+      st->lbuf = xmalloc((size_t)st->lbuf_size);
+
+      if (st->state == TS_STEP_FORWARD || st->state == TS_LINEAR) {
+        // Seek to the same position to read the same line again
+        vim_ignored = vim_fseek(st->fp, search_info.curr_offset, SEEK_SET);
+      }
+      // this will try the same thing again, make sure the offset is
+      // different
+      search_info.curr_offset = 0;
+      continue;
+    }
+
+    retval = (int)findtags_parse_line(st, &tagp, margs, &search_info);
+    if (retval == TAG_MATCH_NEXT) {
+      continue;
+    }
+    if (retval == TAG_MATCH_STOP) {
+      break;
+    }
+    if (retval == TAG_MATCH_FAIL) {
+      semsg(_("E431: Format error in tags file \"%s\""), st->tag_fname);
+      semsg(_("Before byte %" PRId64), (int64_t)vim_ftell(st->fp));
+      st->stop_searching = true;
+      return;
+    }
+
+    // If a match is found, add it to ht_match[] and ga_match[].
+    if (findtags_match_tag(st, &tagp, margs)) {
+      findtags_add_match(st, &tagp, margs, buf_ffname, &hash);
+    }
+  }  // forever
+}
+
+/// Search for tags matching "st->orgpat.pat" in the "st->tag_fname" tags file.
+/// Information needed to search for the tags is in the "st" state structure.
+/// The matching tags are returned in "st". If an error is encountered, then
+/// "st->stop_searching" is set to true.
+static void findtags_in_file(findtags_state_T *st, int flags, char *buf_ffname)
+{
+  findtags_match_args_T margs;
+
+  st->vimconv.vc_type = CONV_NONE;
+  st->tag_file_sorted = NUL;
+  st->fp = NULL;
+  findtags_matchargs_init(&margs, st->flags);
+
+  // A file that doesn't exist is silently ignored.  Only when not a
+  // single file is found, an error message is given (further on).
+  if (curbuf->b_help) {
+    if (!findtags_in_help_init(st)) {
+      return;
+    }
+  }
+
+  st->fp = os_fopen(st->tag_fname, "r");
+  if (st->fp == NULL) {
+    return;
+  }
+
+  if (p_verbose >= 5) {
+    verbose_enter();
+    smsg(_("Searching tags file %s"), st->tag_fname);
+    verbose_leave();
+  }
+  st->did_open = true;   // remember that we found at least one file
+
+  st->state = TS_START;  // we're at the start of the file
+
+  // Read and parse the lines in the file one by one
+  findtags_get_all_tags(st, &margs, buf_ffname);
+
+  if (st->fp != NULL) {
+    fclose(st->fp);
+    st->fp = NULL;
+  }
+  if (st->vimconv.vc_type != CONV_NONE) {
+    convert_setup(&st->vimconv, NULL, NULL);
+  }
+
+  if (margs.sort_error) {
+    semsg(_("E432: Tags file not sorted: %s"), st->tag_fname);
+  }
+
+  // Stop searching if sufficient tags have been found.
+  if (st->match_count >= st->mincount) {
+    st->stop_searching = true;
+  }
+}
+
+/// Copy the tags found by find_tags() to "matchesp".
+/// Returns the number of matches copied.
+static int findtags_copy_matches(findtags_state_T *st, char ***matchesp)
+{
+  const bool name_only = (st->flags & TAG_NAMES);
+  char **matches;
+  int mtt;
+  int i;
+  char *mfp;
+  char *p;
+
+  if (st->match_count > 0) {
+    matches = xmalloc((size_t)st->match_count * sizeof(char *));
+  } else {
+    matches = NULL;
+  }
+  st->match_count = 0;
+  for (mtt = 0; mtt < MT_COUNT; mtt++) {
+    for (i = 0; i < st->ga_match[mtt].ga_len; i++) {
+      mfp = ((char **)(st->ga_match[mtt].ga_data))[i];
+      if (matches == NULL) {
+        xfree(mfp);
+      } else {
+        if (!name_only) {
+          // Change mtt back to zero-based.
+          *mfp = (char)(*mfp - 1);
+
+          // change the TAG_SEP back to NUL
+          for (p = mfp + 1; *p != NUL; p++) {
+            if (*p == TAG_SEP) {
+              *p = NUL;
+            }
+          }
+        }
+        matches[st->match_count++] = mfp;
+      }
+    }
+
+    ga_clear(&st->ga_match[mtt]);
+    hash_clear(&st->ht_match[mtt]);
+  }
+
+  *matchesp = matches;
+  return st->match_count;
+}
+
 /// find_tags() - search for tags in tags files
 ///
 /// Return FAIL if search completely failed (*num_matches will be 0, *matchesp
@@ -1357,94 +2315,33 @@ static int find_tagfunc_tags(char_u *pat, garray_T *ga, int *match_count, int fl
 /// TAG_REGEXP     use "pat" as a regexp
 /// TAG_NOIC       don't always ignore case
 /// TAG_KEEP_LANG  keep language
-/// TAG_CSCOPE     use cscope results for tags
 /// TAG_NO_TAGFUNC do not call the 'tagfunc' function
 ///
 /// @param pat  pattern to search for
 /// @param num_matches  return: number of matches found
 /// @param matchesp  return: array of matches found
-/// @param mincount  MAXCOL: find all matches other: minimal number of matches */
+/// @param mincount  MAXCOL: find all matches
+///                  other: minimal number of matches
 /// @param buf_ffname  name of buffer for priority
-int find_tags(char_u *pat, int *num_matches, char ***matchesp, int flags, int mincount,
-              char_u *buf_ffname)
+int find_tags(char *pat, int *num_matches, char ***matchesp, int flags, int mincount,
+              char *buf_ffname)
 {
-  FILE *fp;
-  char_u *lbuf;                     // line buffer
-  int lbuf_size = LSIZE;                // length of lbuf
-  char_u *tag_fname;                // name of tag file
+  findtags_state_T st;
   tagname_T tn;                         // info for get_tagfname()
   int first_file;                       // trying first tag file
-  tagptrs_T tagp;
-  bool did_open = false;                // did open a tag file
-  bool stop_searching = false;          // stop when match found or error
   int retval = FAIL;                    // return value
-  int is_static;                        // current tag line is static
-  int is_current;                       // file name matches
-  bool eof = false;                     // found end-of-file
-  char_u *p;
-  char_u *s;
-  int i;
-  int tag_file_sorted = NUL;            // !_TAG_FILE_SORTED value
-  struct tag_search_info {      // Binary search file offsets
-    off_T low_offset;           // offset for first char of first line that
-                                // could match
-    off_T high_offset;          // offset of char after last line that could
-                                // match
-    off_T curr_offset;          // Current file offset in search range
-    off_T curr_offset_used;     // curr_offset used when skipping back
-    off_T match_offset;         // Where the binary search found a tag
-    int low_char;               // first char at low_offset
-    int high_char;              // first char at high_offset
-  } search_info;
-  int tagcmp;
-  off_T offset;
   int round;
-  enum {
-    TS_START,                   // at start of file
-    TS_LINEAR,                  // linear searching forward, till EOF
-    TS_BINARY,                // binary searching
-    TS_SKIP_BACK,               // skipping backwards
-    TS_STEP_FORWARD,  // stepping forwards
-  }   state;                    // Current search state
 
-  int cmplen;
-  int match;                    // matches
-  int match_no_ic = 0;          // matches with rm_ic == FALSE
-  int match_re;                 // match with regexp
-  int matchoff = 0;
   int save_emsg_off;
 
-  char *mfp;
-  garray_T ga_match[MT_COUNT];   // stores matches in sequence
-  hashtab_T ht_match[MT_COUNT];  // stores matches by key
-  hash_T hash = 0;
-  int match_count = 0;                          // number of matches found
-  char **matches;
-  int mtt;
   int help_save;
-  int help_pri = 0;
-  char_u *help_lang_find = NULL;           // lang to be found
-  char_u help_lang[3];                          // lang of current tags file
-  char_u *saved_pat = NULL;                // copy of pat[]
-  bool is_txt = false;
-
-  pat_T orgpat;                         // holds unconverted pattern info
-  vimconv_T vimconv;
+  int i;
+  char *saved_pat = NULL;                // copy of pat[]
 
-  int findall = (mincount == MAXCOL || mincount == TAG_MANY);
-  // find all matching tags
-  bool sort_error = false;                      // tags file not sorted
-  int linear;                                   // do a linear search
-  bool sortic = false;                          // tag file sorted in nocase
-  bool line_error = false;                      // syntax error
+  int findall = (mincount == MAXCOL || mincount == TAG_MANY);  // find all matching tags
   int has_re = (flags & TAG_REGEXP);            // regexp used
-  int help_only = (flags & TAG_HELP);
-  int name_only = (flags & TAG_NAMES);
   int noic = (flags & TAG_NOIC);
-  int get_it_again = FALSE;
-  int use_cscope = (flags & TAG_CSCOPE);
   int verbose = (flags & TAG_VERBOSE);
-  int use_tfu = ((flags & TAG_NO_TAGFUNC) == 0);
   int save_p_ic = p_ic;
 
   // Change the value of 'ignorecase' according to 'tagcase' for the
@@ -1469,829 +2366,109 @@ int find_tags(char_u *pat, int *num_matches, char ***matchesp, int flags, int mi
   }
 
   help_save = curbuf->b_help;
-  orgpat.pat = pat;
-  orgpat.regmatch.regprog = NULL;
-  vimconv.vc_type = CONV_NONE;
-
-  /*
-   * Allocate memory for the buffers that are used
-   */
-  lbuf = xmalloc((size_t)lbuf_size);
-  tag_fname = xmalloc(MAXPATHL + 1);
-  for (mtt = 0; mtt < MT_COUNT; mtt++) {
-    ga_init(&ga_match[mtt], sizeof(char *), 100);
-    hash_init(&ht_match[mtt]);
-  }
 
-  STRCPY(tag_fname, "from cscope");             // for error messages
+  findtags_state_init(&st, pat, flags, mincount);
 
-  /*
-   * Initialize a few variables
-   */
-  if (help_only) {                              // want tags from help file
+  // Initialize a few variables
+  if (st.help_only) {                           // want tags from help file
     curbuf->b_help = true;                      // will be restored later
-  } else if (use_cscope) {
-    // Make sure we don't mix help and cscope, confuses Coverity.
-    help_only = false;
-    curbuf->b_help = false;
   }
 
-  orgpat.len = (int)STRLEN(pat);
   if (curbuf->b_help) {
     // When "@ab" is specified use only the "ab" language, otherwise
     // search all languages.
-    if (orgpat.len > 3 && pat[orgpat.len - 3] == '@'
-        && ASCII_ISALPHA(pat[orgpat.len - 2])
-        && ASCII_ISALPHA(pat[orgpat.len - 1])) {
-      saved_pat = vim_strnsave(pat, (size_t)orgpat.len - 3);
-      help_lang_find = &pat[orgpat.len - 2];
-      orgpat.pat = saved_pat;
-      orgpat.len -= 3;
+    if (st.orgpat->len > 3 && pat[st.orgpat->len - 3] == '@'
+        && ASCII_ISALPHA(pat[st.orgpat->len - 2])
+        && ASCII_ISALPHA(pat[st.orgpat->len - 1])) {
+      saved_pat = xstrnsave(pat, (size_t)st.orgpat->len - 3);
+      st.help_lang_find = &pat[st.orgpat->len - 2];
+      st.orgpat->pat = saved_pat;
+      st.orgpat->len -= 3;
     }
   }
-  if (p_tl != 0 && orgpat.len > p_tl) {         // adjust for 'taglength'
-    orgpat.len = (int)p_tl;
+  if (p_tl != 0 && st.orgpat->len > p_tl) {  // adjust for 'taglength'
+    st.orgpat->len = (int)p_tl;
   }
 
   save_emsg_off = emsg_off;
-  emsg_off = TRUE;    // don't want error for invalid RE here
-  prepare_pats(&orgpat, has_re);
+  emsg_off = true;    // don't want error for invalid RE here
+  prepare_pats(st.orgpat, has_re);
   emsg_off = save_emsg_off;
-  if (has_re && orgpat.regmatch.regprog == NULL) {
+  if (has_re && st.orgpat->regmatch.regprog == NULL) {
     goto findtag_end;
   }
 
-  // This is only to avoid a compiler warning for using search_info
-  // uninitialised.
-  CLEAR_FIELD(search_info);
+  retval = findtags_apply_tfu(&st, pat, buf_ffname);
+  if (retval != NOTDONE) {
+    goto findtag_end;
+  }
+
+  // re-initialize the default return value
+  retval = FAIL;
 
-  if (*curbuf->b_p_tfu != NUL && use_tfu && !tfu_in_use) {
-    tfu_in_use = true;
-    retval = find_tagfunc_tags(pat, &ga_match[0], &match_count,
-                               flags, buf_ffname);
-    tfu_in_use = false;
-    if (retval != NOTDONE) {
-      goto findtag_end;
-    }
-  }
-
-  /*
-   * When finding a specified number of matches, first try with matching
-   * case, so binary search can be used, and try ignore-case matches in a
-   * second loop.
-   * When finding all matches, 'tagbsearch' is off, or there is no fixed
-   * string to look for, ignore case right away to avoid going though the
-   * tags files twice.
-   * When the tag file is case-fold sorted, it is either one or the other.
-   * Only ignore case when TAG_NOIC not used or 'ignorecase' set.
-   */
   // Set a flag if the file extension is .txt
   if ((flags & TAG_KEEP_LANG)
-      && help_lang_find == NULL
+      && st.help_lang_find == NULL
       && curbuf->b_fname != NULL
-      && (i = (int)STRLEN(curbuf->b_fname)) > 4
+      && (i = (int)strlen(curbuf->b_fname)) > 4
       && STRICMP(curbuf->b_fname + i - 4, ".txt") == 0) {
-    is_txt = true;
-  }
-  orgpat.regmatch.rm_ic = ((p_ic || !noic)
-                           && (findall || orgpat.headlen == 0 || !p_tbs));
-  for (round = 1; round <= 2; ++round) {
-    linear = (orgpat.headlen == 0 || !p_tbs || round == 2);
+    st.is_txt = true;
+  }
+
+  // When finding a specified number of matches, first try with matching
+  // case, so binary search can be used, and try ignore-case matches in a
+  // second loop.
+  // When finding all matches, 'tagbsearch' is off, or there is no fixed
+  // string to look for, ignore case right away to avoid going though the
+  // tags files twice.
+  // When the tag file is case-fold sorted, it is either one or the other.
+  // Only ignore case when TAG_NOIC not used or 'ignorecase' set.
+  st.orgpat->regmatch.rm_ic = ((p_ic || !noic)
+                               && (findall || st.orgpat->headlen == 0 || !p_tbs));
+  for (round = 1; round <= 2; round++) {
+    st.linear = (st.orgpat->headlen == 0 || !p_tbs || round == 2);
 
     // Try tag file names from tags option one by one.
     for (first_file = true;
-         use_cscope || get_tagfname(&tn, first_file, tag_fname) == OK;
+         get_tagfname(&tn, first_file, st.tag_fname) == OK;
          first_file = false) {
-      // A file that doesn't exist is silently ignored.  Only when not a
-      // single file is found, an error message is given (further on).
-      if (use_cscope) {
-        fp = NULL;  // avoid GCC warning
-      } else {
-        if (curbuf->b_help) {
-          // Keep en if the file extension is .txt
-          if (is_txt) {
-            STRCPY(help_lang, "en");
-          } else {
-            // Prefer help tags according to 'helplang'.  Put the
-            // two-letter language name in help_lang[].
-            i = (int)STRLEN(tag_fname);
-            if (i > 3 && tag_fname[i - 3] == '-') {
-              STRCPY(help_lang, tag_fname + i - 2);
-            } else {
-              STRCPY(help_lang, "en");
-            }
-          }
-
-          // When searching for a specific language skip tags files
-          // for other languages.
-          if (help_lang_find != NULL
-              && STRICMP(help_lang, help_lang_find) != 0) {
-            continue;
-          }
-
-          // For CTRL-] in a help file prefer a match with the same
-          // language.
-          if ((flags & TAG_KEEP_LANG)
-              && help_lang_find == NULL
-              && curbuf->b_fname != NULL
-              && (i = (int)STRLEN(curbuf->b_fname)) > 4
-              && curbuf->b_fname[i - 1] == 'x'
-              && curbuf->b_fname[i - 4] == '.'
-              && STRNICMP(curbuf->b_fname + i - 3, help_lang, 2) == 0) {
-            help_pri = 0;
-          } else {
-            help_pri = 1;
-            for (s = p_hlg; *s != NUL; ++s) {
-              if (STRNICMP(s, help_lang, 2) == 0) {
-                break;
-              }
-              help_pri++;
-              if ((s = (char_u *)vim_strchr((char *)s, ',')) == NULL) {
-                break;
-              }
-            }
-            if (s == NULL || *s == NUL) {
-              // Language not in 'helplang': use last, prefer English,
-              // unless found already.
-              help_pri++;
-              if (STRICMP(help_lang, "en") != 0) {
-                help_pri++;
-              }
-            }
-          }
-        }
-
-        if ((fp = os_fopen((char *)tag_fname, "r")) == NULL) {
-          continue;
-        }
-
-        if (p_verbose >= 5) {
-          verbose_enter();
-          smsg(_("Searching tags file %s"), tag_fname);
-          verbose_leave();
-        }
-      }
-      did_open = true;      // remember that we found at least one file
-
-      state = TS_START;     // we're at the start of the file
-
-      /*
-       * Read and parse the lines in the file one by one
-       */
-      for (;;) {
-        // check for CTRL-C typed, more often when jumping around
-        if (state == TS_BINARY || state == TS_SKIP_BACK) {
-          line_breakcheck();
-        } else {
-          fast_breakcheck();
-        }
-        if ((flags & TAG_INS_COMP)) {   // Double brackets for gcc
-          ins_compl_check_keys(30, false);
-        }
-        if (got_int || ins_compl_interrupted()) {
-          stop_searching = true;
-          break;
-        }
-        // When mincount is TAG_MANY, stop when enough matches have been
-        // found (for completion).
-        if (mincount == TAG_MANY && match_count >= TAG_MANY) {
-          stop_searching = true;
-          retval = OK;
-          break;
-        }
-        if (get_it_again) {
-          goto line_read_in;
-        }
-        /*
-         * For binary search: compute the next offset to use.
-         */
-        if (state == TS_BINARY) {
-          offset = search_info.low_offset + ((search_info.high_offset
-                                              - search_info.low_offset) / 2);
-          if (offset == search_info.curr_offset) {
-            break;              // End the binary search without a match.
-          } else {
-            search_info.curr_offset = offset;
-          }
-        } else if (state == TS_SKIP_BACK) {
-          // Skipping back (after a match during binary search).
-          search_info.curr_offset -= lbuf_size * 2;
-          if (search_info.curr_offset < 0) {
-            search_info.curr_offset = 0;
-            rewind(fp);
-            state = TS_STEP_FORWARD;
-          }
-        }
-
-        /*
-         * When jumping around in the file, first read a line to find the
-         * start of the next line.
-         */
-        if (state == TS_BINARY || state == TS_SKIP_BACK) {
-          // Adjust the search file offset to the correct position
-          search_info.curr_offset_used = search_info.curr_offset;
-          vim_fseek(fp, search_info.curr_offset, SEEK_SET);
-          eof = vim_fgets(lbuf, lbuf_size, fp);
-          if (!eof && search_info.curr_offset != 0) {
-            // The explicit cast is to work around a bug in gcc 3.4.2
-            // (repeated below).
-            search_info.curr_offset = vim_ftell(fp);
-            if (search_info.curr_offset == search_info.high_offset) {
-              // oops, gone a bit too far; try from low offset
-              vim_fseek(fp, search_info.low_offset, SEEK_SET);
-              search_info.curr_offset = search_info.low_offset;
-            }
-            eof = vim_fgets(lbuf, lbuf_size, fp);
-          }
-          // skip empty and blank lines
-          while (!eof && vim_isblankline(lbuf)) {
-            search_info.curr_offset = vim_ftell(fp);
-            eof = vim_fgets(lbuf, lbuf_size, fp);
-          }
-          if (eof) {
-            // Hit end of file.  Skip backwards.
-            state = TS_SKIP_BACK;
-            search_info.match_offset = vim_ftell(fp);
-            search_info.curr_offset = search_info.curr_offset_used;
-            continue;
-          }
-        }
-        /*
-         * Not jumping around in the file: Read the next line.
-         */
-        else {
-          // skip empty and blank lines
-          do {
-            eof = use_cscope
-              ? cs_fgets(lbuf, lbuf_size)
-              : vim_fgets(lbuf, lbuf_size, fp);
-          } while (!eof && vim_isblankline(lbuf));
-
-          if (eof) {
-            break;                                  // end of file
-          }
-        }
-line_read_in:
-
-        if (vimconv.vc_type != CONV_NONE) {
-          char_u *conv_line;
-          int len;
-
-          // Convert every line.  Converting the pattern from 'enc' to
-          // the tags file encoding doesn't work, because characters are
-          // not recognized.
-          conv_line = string_convert(&vimconv, lbuf, NULL);
-          if (conv_line != NULL) {
-            // Copy or swap lbuf and conv_line.
-            len = (int)STRLEN(conv_line) + 1;
-            if (len > lbuf_size) {
-              xfree(lbuf);
-              lbuf = conv_line;
-              lbuf_size = len;
-            } else {
-              STRCPY(lbuf, conv_line);
-              xfree(conv_line);
-            }
-          }
-        }
-
-        /*
-         * When still at the start of the file, check for Emacs tags file
-         * format, and for "not sorted" flag.
-         */
-        if (state == TS_START) {
-          // The header ends when the line sorts below "!_TAG_".  When
-          // case is folded lower case letters sort before "_".
-          if (STRNCMP(lbuf, "!_TAG_", 6) <= 0
-              || (lbuf[0] == '!' && ASCII_ISLOWER(lbuf[1]))) {
-            if (STRNCMP(lbuf, "!_TAG_", 6) != 0) {
-              // Non-header item before the header, e.g. "!" itself.
-              goto parse_line;
-            }
-
-            /*
-             * Read header line.
-             */
-            if (STRNCMP(lbuf, "!_TAG_FILE_SORTED\t", 18) == 0) {
-              tag_file_sorted = lbuf[18];
-            }
-            if (STRNCMP(lbuf, "!_TAG_FILE_ENCODING\t", 20) == 0) {
-              // Prepare to convert every line from the specified
-              // encoding to 'encoding'.
-              for (p = lbuf + 20; *p > ' ' && *p < 127; p++) {}
-              *p = NUL;
-              convert_setup(&vimconv, lbuf + 20, p_enc);
-            }
-
-            // Read the next line.  Unrecognized flags are ignored.
-            continue;
-          }
-
-          // Headers ends.
-
-          /*
-           * When there is no tag head, or ignoring case, need to do a
-           * linear search.
-           * When no "!_TAG_" is found, default to binary search.  If
-           * the tag file isn't sorted, the second loop will find it.
-           * When "!_TAG_FILE_SORTED" found: start binary search if
-           * flag set.
-           * For cscope, it's always linear.
-           */
-          if (linear || use_cscope) {
-            state = TS_LINEAR;
-          } else if (tag_file_sorted == NUL) {
-            state = TS_BINARY;
-          } else if (tag_file_sorted == '1') {
-            state = TS_BINARY;
-          } else if (tag_file_sorted == '2') {
-            state = TS_BINARY;
-            sortic = true;
-            orgpat.regmatch.rm_ic = (p_ic || !noic);
-          } else {
-            state = TS_LINEAR;
-          }
-
-          if (state == TS_BINARY && orgpat.regmatch.rm_ic && !sortic) {
-            // Binary search won't work for ignoring case, use linear
-            // search.
-            linear = true;
-            state = TS_LINEAR;
-          }
-
-          // When starting a binary search, get the size of the file and
-          // compute the first offset.
-          if (state == TS_BINARY) {
-            if (vim_fseek(fp, 0, SEEK_END) != 0) {
-              // can't seek, don't use binary search
-              state = TS_LINEAR;
-            } else {
-              // Get the tag file size.
-              // Don't use lseek(), it doesn't work
-              // properly on MacOS Catalina.
-              const off_T filesize = vim_ftell(fp);
-              vim_fseek(fp, 0, SEEK_SET);
-
-              // Calculate the first read offset in the file.  Start
-              // the search in the middle of the file.
-              search_info.low_offset = 0;
-              search_info.low_char = 0;
-              search_info.high_offset = filesize;
-              search_info.curr_offset = 0;
-              search_info.high_char = 0xff;
-            }
-            continue;
-          }
-        }
-
-parse_line:
-        // When the line is too long the NUL will not be in the
-        // last-but-one byte (see vim_fgets()).
-        // Has been reported for Mozilla JS with extremely long names.
-        // In that case we need to increase lbuf_size.
-        if (lbuf[lbuf_size - 2] != NUL && !use_cscope) {
-          lbuf_size *= 2;
-          xfree(lbuf);
-          lbuf = xmalloc((size_t)lbuf_size);
-          // this will try the same thing again, make sure the offset is
-          // different
-          search_info.curr_offset = 0;
-          continue;
-        }
-
-        // Figure out where the different strings are in this line.
-        // For "normal" tags: Do a quick check if the tag matches.
-        // This speeds up tag searching a lot!
-        if (orgpat.headlen) {
-          CLEAR_FIELD(tagp);
-          tagp.tagname = lbuf;
-          tagp.tagname_end = (char_u *)vim_strchr((char *)lbuf, TAB);
-          if (tagp.tagname_end == NULL) {
-            // Corrupted tag line.
-            line_error = true;
-            break;
-          }
-
-          /*
-           * Skip this line if the length of the tag is different and
-           * there is no regexp, or the tag is too short.
-           */
-          cmplen = (int)(tagp.tagname_end - tagp.tagname);
-          if (p_tl != 0 && cmplen > p_tl) {         // adjust for 'taglength'
-            cmplen = (int)p_tl;
-          }
-          if (has_re && orgpat.headlen < cmplen) {
-            cmplen = orgpat.headlen;
-          } else if (state == TS_LINEAR && orgpat.headlen != cmplen) {
-            continue;
-          }
-
-          if (state == TS_BINARY) {
-            /*
-             * Simplistic check for unsorted tags file.
-             */
-            i = (int)tagp.tagname[0];
-            if (sortic) {
-              i = TOUPPER_ASC(tagp.tagname[0]);
-            }
-            if (i < search_info.low_char || i > search_info.high_char) {
-              sort_error = true;
-            }
-
-            /*
-             * Compare the current tag with the searched tag.
-             */
-            if (sortic) {
-              tagcmp = tag_strnicmp(tagp.tagname, orgpat.head,
-                                    (size_t)cmplen);
-            } else {
-              tagcmp = STRNCMP(tagp.tagname, orgpat.head, cmplen);
-            }
-
-            /*
-             * A match with a shorter tag means to search forward.
-             * A match with a longer tag means to search backward.
-             */
-            if (tagcmp == 0) {
-              if (cmplen < orgpat.headlen) {
-                tagcmp = -1;
-              } else if (cmplen > orgpat.headlen) {
-                tagcmp = 1;
-              }
-            }
-
-            if (tagcmp == 0) {
-              // We've located the tag, now skip back and search
-              // forward until the first matching tag is found.
-              state = TS_SKIP_BACK;
-              search_info.match_offset = search_info.curr_offset;
-              continue;
-            }
-            if (tagcmp < 0) {
-              search_info.curr_offset = vim_ftell(fp);
-              if (search_info.curr_offset < search_info.high_offset) {
-                search_info.low_offset = search_info.curr_offset;
-                if (sortic) {
-                  search_info.low_char =
-                    TOUPPER_ASC(tagp.tagname[0]);
-                } else {
-                  search_info.low_char = tagp.tagname[0];
-                }
-                continue;
-              }
-            }
-            if (tagcmp > 0
-                && search_info.curr_offset != search_info.high_offset) {
-              search_info.high_offset = search_info.curr_offset;
-              if (sortic) {
-                search_info.high_char =
-                  TOUPPER_ASC(tagp.tagname[0]);
-              } else {
-                search_info.high_char = tagp.tagname[0];
-              }
-              continue;
-            }
-
-            // No match yet and are at the end of the binary search.
-            break;
-          } else if (state == TS_SKIP_BACK) {
-            assert(cmplen >= 0);
-            if (mb_strnicmp(tagp.tagname, orgpat.head, (size_t)cmplen) != 0) {
-              state = TS_STEP_FORWARD;
-            } else {
-              // Have to skip back more.  Restore the curr_offset
-              // used, otherwise we get stuck at a long line.
-              search_info.curr_offset = search_info.curr_offset_used;
-            }
-            continue;
-          } else if (state == TS_STEP_FORWARD) {
-            assert(cmplen >= 0);
-            if (mb_strnicmp(tagp.tagname, orgpat.head, (size_t)cmplen) != 0) {
-              if ((off_T)vim_ftell(fp) > search_info.match_offset) {
-                break;                  // past last match
-              } else {
-                continue;               // before first match
-              }
-            }
-          } else {
-            // skip this match if it can't match
-            assert(cmplen >= 0);
-          }
-          if (mb_strnicmp(tagp.tagname, orgpat.head, (size_t)cmplen) != 0) {
-            continue;
-          }
-
-          // Can be a matching tag, isolate the file name and command.
-          tagp.fname = tagp.tagname_end + 1;
-          tagp.fname_end = (char_u *)vim_strchr((char *)tagp.fname, TAB);
-          tagp.command = tagp.fname_end + 1;
-          if (tagp.fname_end == NULL) {
-            i = FAIL;
-          } else {
-            i = OK;
-          }
-        } else {
-          i = parse_tag_line(lbuf,
-                             &tagp);
-        }
-        if (i == FAIL) {
-          line_error = true;
-          break;
-        }
-
-        /*
-         * First try matching with the pattern literally (also when it is
-         * a regexp).
-         */
-        cmplen = (int)(tagp.tagname_end - tagp.tagname);
-        if (p_tl != 0 && cmplen > p_tl) {           // adjust for 'taglength'
-          cmplen = (int)p_tl;
-        }
-        // if tag length does not match, don't try comparing
-        if (orgpat.len != cmplen) {
-          match = FALSE;
-        } else {
-          if (orgpat.regmatch.rm_ic) {
-            assert(cmplen >= 0);
-            match = mb_strnicmp(tagp.tagname, orgpat.pat, (size_t)cmplen) == 0;
-            if (match) {
-              match_no_ic = (STRNCMP(tagp.tagname, orgpat.pat,
-                                     cmplen) == 0);
-            }
-          } else {
-            match = (STRNCMP(tagp.tagname, orgpat.pat, cmplen) == 0);
-          }
-        }
-
-        /*
-         * Has a regexp: Also find tags matching regexp.
-         */
-        match_re = FALSE;
-        if (!match && orgpat.regmatch.regprog != NULL) {
-          int cc;
-
-          cc = *tagp.tagname_end;
-          *tagp.tagname_end = NUL;
-          match = vim_regexec(&orgpat.regmatch, (char *)tagp.tagname, (colnr_T)0);
-          if (match) {
-            matchoff = (int)(orgpat.regmatch.startp[0] - tagp.tagname);
-            if (orgpat.regmatch.rm_ic) {
-              orgpat.regmatch.rm_ic = false;
-              match_no_ic = vim_regexec(&orgpat.regmatch, (char *)tagp.tagname, (colnr_T)0);
-              orgpat.regmatch.rm_ic = true;
-            }
-          }
-          *tagp.tagname_end = (char_u)cc;
-          match_re = true;
-        }
-
-        // If a match is found, add it to ht_match[] and ga_match[].
-        if (match) {
-          size_t len = 0;
-
-          if (use_cscope) {
-            // Don't change the ordering, always use the same table.
-            mtt = MT_GL_OTH;
-          } else {
-            // Decide in which array to store this match.
-            is_current = test_for_current(tagp.fname, tagp.fname_end, tag_fname,
-                                          buf_ffname);
-            is_static = test_for_static(&tagp);
-
-            // Decide in which of the sixteen tables to store this match.
-            if (is_static) {
-              if (is_current) {
-                mtt = MT_ST_CUR;
-              } else {
-                mtt = MT_ST_OTH;
-              }
-            } else {
-              if (is_current) {
-                mtt = MT_GL_CUR;
-              } else {
-                mtt = MT_GL_OTH;
-              }
-            }
-            if (orgpat.regmatch.rm_ic && !match_no_ic) {
-              mtt += MT_IC_OFF;
-            }
-            if (match_re) {
-              mtt += MT_RE_OFF;
-            }
-          }
-
-          // Add the found match in ht_match[mtt] and ga_match[mtt].
-          // Store the info we need later, which depends on the kind of
-          // tags we are dealing with.
-          if (help_only) {
-#define ML_EXTRA 3
-            // Append the help-heuristic number after the tagname, for
-            // sorting it later.  The heuristic is ignored for
-            // detecting duplicates.
-            // The format is {tagname}@{lang}NUL{heuristic}NUL
-            *tagp.tagname_end = NUL;
-            len = (size_t)(tagp.tagname_end - tagp.tagname);
-            mfp = xmalloc(sizeof(char) + len + 10 + ML_EXTRA + 1);
-
-            p = (char_u *)mfp;
-            STRCPY(p, tagp.tagname);
-            p[len] = '@';
-            STRCPY(p + len + 1, help_lang);
-            snprintf((char *)p + len + 1 + ML_EXTRA, STRLEN(p) + len + 1 + ML_EXTRA, "%06d",
-                     help_heuristic((char *)tagp.tagname,
-                                    match_re ? matchoff : 0, !match_no_ic)
-                     + help_pri);
-
-            *tagp.tagname_end = TAB;
-          } else if (name_only) {
-            if (get_it_again) {
-              char_u *temp_end = tagp.command;
-
-              if (*temp_end == '/') {
-                while (*temp_end && *temp_end != '\r'
-                       && *temp_end != '\n'
-                       && *temp_end != '$') {
-                  temp_end++;
-                }
-              }
-
-              if (tagp.command + 2 < temp_end) {
-                len = (size_t)(temp_end - tagp.command - 2);
-                mfp = xmalloc(len + 2);
-                STRLCPY(mfp, tagp.command + 2, len + 1);
-              } else {
-                mfp = NULL;
-              }
-              get_it_again = false;
-            } else {
-              len = (size_t)(tagp.tagname_end - tagp.tagname);
-              mfp = xmalloc(sizeof(char) + len + 1);
-              STRLCPY(mfp, tagp.tagname, len + 1);
-
-              // if wanted, re-read line to get long form too
-              if (State & MODE_INSERT) {
-                get_it_again = p_sft;
-              }
-            }
-          } else {
-            size_t tag_fname_len = STRLEN(tag_fname);
-            // Save the tag in a buffer.
-            // Use 0x02 to separate fields (Can't use NUL, because the
-            // hash key is terminated by NUL).
-            // Emacs tag: <mtt><tag_fname><0x02><ebuf><0x02><lbuf><NUL>
-            // other tag: <mtt><tag_fname><0x02><0x02><lbuf><NUL>
-            // without Emacs tags: <mtt><tag_fname><0x02><lbuf><NUL>
-            // Here <mtt> is the "mtt" value plus 1 to avoid NUL.
-            len = tag_fname_len + STRLEN(lbuf) + 3;
-            mfp = xmalloc(sizeof(char) + len + 1);
-            p = (char_u *)mfp;
-            p[0] = (char_u)(mtt + 1);
-            STRCPY(p + 1, tag_fname);
-#ifdef BACKSLASH_IN_FILENAME
-            // Ignore differences in slashes, avoid adding
-            // both path/file and path\file.
-            slash_adjust(p + 1);
-#endif
-            p[tag_fname_len + 1] = TAG_SEP;
-            s = p + 1 + tag_fname_len + 1;
-            STRCPY(s, lbuf);
-          }
-
-          if (mfp != NULL) {
-            hashitem_T *hi;
-
-            // Don't add identical matches.
-            // Add all cscope tags, because they are all listed.
-            // "mfp" is used as a hash key, there is a NUL byte to end
-            // the part that matters for comparing, more bytes may
-            // follow after it.  E.g. help tags store the priority
-            // after the NUL.
-            if (use_cscope) {
-              hash++;
-            } else {
-              hash = hash_hash((char_u *)mfp);
-            }
-            hi = hash_lookup(&ht_match[mtt], (const char *)mfp,
-                             STRLEN(mfp), hash);
-            if (HASHITEM_EMPTY(hi)) {
-              hash_add_item(&ht_match[mtt], hi, (char_u *)mfp, hash);
-              ga_grow(&ga_match[mtt], 1);
-              ((char **)(ga_match[mtt].ga_data))[ga_match[mtt].ga_len++] = mfp;
-              match_count++;
-            } else {
-              // duplicate tag, drop it
-              xfree(mfp);
-            }
-          }
-        }
-        if (use_cscope && eof) {
-          break;
-        }
-      }   // forever
-
-      if (line_error) {
-        semsg(_("E431: Format error in tags file \"%s\""), tag_fname);
-        if (!use_cscope) {
-          semsg(_("Before byte %" PRId64), (int64_t)vim_ftell(fp));
-        }
-        stop_searching = true;
-        line_error = false;
-      }
-
-      if (!use_cscope) {
-        fclose(fp);
-      }
-      if (vimconv.vc_type != CONV_NONE) {
-        convert_setup(&vimconv, NULL, NULL);
-      }
-
-      tag_file_sorted = NUL;
-      if (sort_error) {
-        semsg(_("E432: Tags file not sorted: %s"), tag_fname);
-        sort_error = false;
-      }
-
-      /*
-       * Stop searching if sufficient tags have been found.
-       */
-      if (match_count >= mincount) {
+      findtags_in_file(&st, flags, buf_ffname);
+      if (st.stop_searching) {
         retval = OK;
-        stop_searching = true;
-      }
-
-      if (stop_searching || use_cscope) {
         break;
       }
     }   // end of for-each-file loop
 
-    if (!use_cscope) {
-      tagname_free(&tn);
-    }
+    tagname_free(&tn);
 
     // stop searching when already did a linear search, or when TAG_NOIC
     // used, and 'ignorecase' not set or already did case-ignore search
-    if (stop_searching || linear || (!p_ic && noic) || orgpat.regmatch.rm_ic) {
-      break;
-    }
-    if (use_cscope) {
+    if (st.stop_searching || st.linear || (!p_ic && noic)
+        || st.orgpat->regmatch.rm_ic) {
       break;
     }
-    orgpat.regmatch.rm_ic = TRUE;       // try another time while ignoring case
+
+    // try another time while ignoring case
+    st.orgpat->regmatch.rm_ic = true;
   }
 
-  if (!stop_searching) {
-    if (!did_open && verbose) {         // never opened any tags file
+  if (!st.stop_searching) {
+    if (!st.did_open && verbose) {  // never opened any tags file
       emsg(_("E433: No tags file"));
     }
     retval = OK;                // It's OK even when no tag found
   }
 
 findtag_end:
-  xfree(lbuf);
-  vim_regfree(orgpat.regmatch.regprog);
-  xfree(tag_fname);
+  findtags_state_free(&st);
 
-  /*
-   * Move the matches from the ga_match[] arrays into one list of
-   * matches.  When retval == FAIL, free the matches.
-   */
+  // Move the matches from the ga_match[] arrays into one list of
+  // matches.  When retval == FAIL, free the matches.
   if (retval == FAIL) {
-    match_count = 0;
+    st.match_count = 0;
   }
 
-  if (match_count > 0) {
-    matches = xmalloc((size_t)match_count * sizeof(char *));
-  } else {
-    matches = NULL;
-  }
-  match_count = 0;
-  for (mtt = 0; mtt < MT_COUNT; mtt++) {
-    for (i = 0; i < ga_match[mtt].ga_len; i++) {
-      mfp = ((char **)(ga_match[mtt].ga_data))[i];
-      if (matches == NULL) {
-        xfree(mfp);
-      } else {
-        if (!name_only) {
-          // Change mtt back to zero-based.
-          *mfp = (char)(*mfp - 1);
-
-          // change the TAG_SEP back to NUL
-          for (p = (char_u *)mfp + 1; *p != NUL; p++) {
-            if (*p == TAG_SEP) {
-              *p = NUL;
-            }
-          }
-        }
-        matches[match_count++] = mfp;
-      }
-    }
-
-    ga_clear(&ga_match[mtt]);
-    hash_clear(&ht_match[mtt]);
-  }
-
-  *matchesp = matches;
-  *num_matches = match_count;
+  *num_matches = findtags_copy_matches(&st, matchesp);
 
   curbuf->b_help = help_save;
   xfree(saved_pat);
@@ -2303,19 +2480,17 @@ findtag_end:
 
 static garray_T tag_fnames = GA_EMPTY_INIT_VALUE;
 
-/*
- * Callback function for finding all "tags" and "tags-??" files in
- * 'runtimepath' doc directories.
- */
+// Callback function for finding all "tags" and "tags-??" files in
+// 'runtimepath' doc directories.
 static void found_tagfile_cb(char *fname, void *cookie)
 {
-  char_u *const tag_fname = vim_strsave((char_u *)fname);
+  char *const tag_fname = xstrdup(fname);
 
 #ifdef BACKSLASH_IN_FILENAME
   slash_adjust(tag_fname);
 #endif
   simplify_filename(tag_fname);
-  GA_APPEND(char_u *, &tag_fnames, tag_fname);
+  GA_APPEND(char *, &tag_fnames, tag_fname);
 }
 
 #if defined(EXITFREE)
@@ -2334,25 +2509,23 @@ void free_tag_stuff(void)
 /// For help files, use "tags" file only.
 ///
 /// @param tnp  holds status info
-/// @param first  TRUE when first file name is wanted
+/// @param first  true when first file name is wanted
 /// @param buf  pointer to buffer of MAXPATHL chars
 ///
 /// @return  FAIL if no more tag file names, OK otherwise.
-int get_tagfname(tagname_T *tnp, int first, char_u *buf)
+int get_tagfname(tagname_T *tnp, int first, char *buf)
 {
-  char_u *fname = NULL;
-  char_u *r_ptr;
+  char *fname = NULL;
+  char *r_ptr;
 
   if (first) {
     CLEAR_POINTER(tnp);
   }
 
   if (curbuf->b_help) {
-    /*
-     * For help files it's done in a completely different way:
-     * Find "doc/tags" and "doc/tags-??" in all directories in
-     * 'runtimepath'.
-     */
+    // For help files it's done in a completely different way:
+    // Find "doc/tags" and "doc/tags-??" in all directories in
+    // 'runtimepath'.
     if (first) {
       ga_clear_strings(&tag_fnames);
       ga_init(&tag_fnames, (int)sizeof(char *), 10);
@@ -2366,7 +2539,7 @@ int get_tagfname(tagname_T *tnp, int first, char_u *buf)
       if (tnp->tn_hf_idx > tag_fnames.ga_len || *p_hf == NUL) {
         return FAIL;
       }
-      ++tnp->tn_hf_idx;
+      tnp->tn_hf_idx++;
       STRCPY(buf, p_hf);
       STRCPY(path_tail((char *)buf), "tags");
 #ifdef BACKSLASH_IN_FILENAME
@@ -2375,12 +2548,12 @@ int get_tagfname(tagname_T *tnp, int first, char_u *buf)
       simplify_filename(buf);
 
       for (int i = 0; i < tag_fnames.ga_len; i++) {
-        if (STRCMP(buf, ((char **)(tag_fnames.ga_data))[i]) == 0) {
+        if (strcmp(buf, ((char **)(tag_fnames.ga_data))[i]) == 0) {
           return FAIL;  // avoid duplicate file names
         }
       }
     } else {
-      STRLCPY(buf, ((char **)(tag_fnames.ga_data))[tnp->tn_hf_idx++], MAXPATHL);
+      xstrlcpy(buf, ((char **)(tag_fnames.ga_data))[tnp->tn_hf_idx++], MAXPATHL);
     }
     return OK;
   }
@@ -2388,16 +2561,14 @@ int get_tagfname(tagname_T *tnp, int first, char_u *buf)
   if (first) {
     // Init.  We make a copy of 'tags', because autocommands may change
     // the value without notifying us.
-    tnp->tn_tags = vim_strsave((*curbuf->b_p_tags != NUL) ? curbuf->b_p_tags : p_tags);
-    tnp->tn_np = (char *)tnp->tn_tags;
+    tnp->tn_tags = xstrdup((*curbuf->b_p_tags != NUL) ? curbuf->b_p_tags : p_tags);
+    tnp->tn_np = tnp->tn_tags;
   }
 
-  /*
-   * Loop until we have found a file name that can be used.
-   * There are two states:
-   * tnp->tn_did_filefind_init == FALSE: setup for next part in 'tags'.
-   * tnp->tn_did_filefind_init == TRUE: find next file in this part.
-   */
+  // Loop until we have found a file name that can be used.
+  // There are two states:
+  // tnp->tn_did_filefind_init == false: setup for next part in 'tags'.
+  // tnp->tn_did_filefind_init == true: find next file in this part.
   for (;;) {
     if (tnp->tn_did_filefind_init) {
       fname = vim_findfile(tnp->tn_search_ctx);
@@ -2405,9 +2576,9 @@ int get_tagfname(tagname_T *tnp, int first, char_u *buf)
         break;
       }
 
-      tnp->tn_did_filefind_init = FALSE;
+      tnp->tn_did_filefind_init = false;
     } else {
-      char_u *filename = NULL;
+      char *filename = NULL;
 
       // Stop when used all parts of 'tags'.
       if (*tnp->tn_np == NUL) {
@@ -2416,26 +2587,24 @@ int get_tagfname(tagname_T *tnp, int first, char_u *buf)
         return FAIL;
       }
 
-      /*
-       * Copy next file name into buf.
-       */
+      // Copy next file name into buf.
       buf[0] = NUL;
-      (void)copy_option_part(&tnp->tn_np, (char *)buf, MAXPATHL - 1, " ,");
+      (void)copy_option_part(&tnp->tn_np, buf, MAXPATHL - 1, " ,");
 
       r_ptr = vim_findfile_stopdir(buf);
       // move the filename one char forward and truncate the
       // filepath with a NUL
-      filename = (char_u *)path_tail((char *)buf);
+      filename = path_tail(buf);
       STRMOVE(filename + 1, filename);
       *filename++ = NUL;
 
       tnp->tn_search_ctx = vim_findfile_init(buf, filename,
                                              r_ptr, 100,
-                                             FALSE,                   // don't free visited list
+                                             false,                   // don't free visited list
                                              FINDFILE_FILE,           // we search for a file
-                                             tnp->tn_search_ctx, true, (char_u *)curbuf->b_ffname);
+                                             tnp->tn_search_ctx, true, curbuf->b_ffname);
       if (tnp->tn_search_ctx != NULL) {
-        tnp->tn_did_filefind_init = TRUE;
+        tnp->tn_did_filefind_init = true;
       }
     }
   }
@@ -2445,9 +2614,7 @@ int get_tagfname(tagname_T *tnp, int first, char_u *buf)
   return OK;
 }
 
-/*
- * Free the contents of a tagname_T that was filled by get_tagfname().
- */
+// Free the contents of a tagname_T that was filled by get_tagfname().
 void tagname_free(tagname_T *tnp)
 {
   xfree(tnp->tn_tags);
@@ -2459,18 +2626,18 @@ void tagname_free(tagname_T *tnp)
 /// Parse one line from the tags file. Find start/end of tag name, start/end of
 /// file name and start of search pattern.
 ///
-/// If is_etag is TRUE, tagp->fname and tagp->fname_end are not set.
+/// If is_etag is true, tagp->fname and tagp->fname_end are not set.
 ///
 /// @param lbuf  line to be parsed
 ///
 /// @return  FAIL if there is a format error in this line, OK otherwise.
-static int parse_tag_line(char_u *lbuf, tagptrs_T *tagp)
+static int parse_tag_line(char *lbuf, tagptrs_T *tagp)
 {
-  char_u *p;
+  char *p;
 
   // Isolate the tagname, from lbuf up to the first white
   tagp->tagname = lbuf;
-  p = (char_u *)vim_strchr((char *)lbuf, TAB);
+  p = vim_strchr(lbuf, TAB);
   if (p == NULL) {
     return FAIL;
   }
@@ -2481,7 +2648,7 @@ static int parse_tag_line(char_u *lbuf, tagptrs_T *tagp)
     p++;
   }
   tagp->fname = p;
-  p = (char_u *)vim_strchr((char *)p, TAB);
+  p = vim_strchr(p, TAB);
   if (p == NULL) {
     return FAIL;
   }
@@ -2499,44 +2666,42 @@ static int parse_tag_line(char_u *lbuf, tagptrs_T *tagp)
   return OK;
 }
 
-/*
- * Check if tagname is a static tag
- *
- * Static tags produced by the older ctags program have the format:
- *      'file:tag  file  /pattern'.
- * This is only recognized when both occurrence of 'file' are the same, to
- * avoid recognizing "string::string" or ":exit".
- *
- * Static tags produced by the new ctags program have the format:
- *      'tag  file  /pattern/;"<Tab>file:'          "
- *
- * Return TRUE if it is a static tag and adjust *tagname to the real tag.
- * Return FALSE if it is not a static tag.
- */
+// Check if tagname is a static tag
+//
+// Static tags produced by the older ctags program have the format:
+//      'file:tag  file  /pattern'.
+// This is only recognized when both occurrence of 'file' are the same, to
+// avoid recognizing "string::string" or ":exit".
+//
+// Static tags produced by the new ctags program have the format:
+//      'tag  file  /pattern/;"<Tab>file:'          "
+//
+// Return true if it is a static tag and adjust *tagname to the real tag.
+// Return false if it is not a static tag.
 static bool test_for_static(tagptrs_T *tagp)
 {
-  char_u *p;
+  char *p;
 
   // Check for new style static tag ":...<Tab>file:[<Tab>...]"
   p = tagp->command;
-  while ((p = (char_u *)vim_strchr((char *)p, '\t')) != NULL) {
+  while ((p = vim_strchr(p, '\t')) != NULL) {
     p++;
-    if (STRNCMP(p, "file:", 5) == 0) {
-      return TRUE;
+    if (strncmp(p, "file:", 5) == 0) {
+      return true;
     }
   }
 
-  return FALSE;
+  return false;
 }
 
-// Returns the length of a matching tag line.
-static size_t matching_line_len(const char_u *const lbuf)
+/// @return  the length of a matching tag line.
+static size_t matching_line_len(const char *const lbuf)
 {
-  const char_u *p = lbuf + 1;
+  const char *p = lbuf + 1;
 
   // does the same thing as parse_match()
-  p += STRLEN(p) + 1;
-  return (size_t)(p - lbuf) + STRLEN(p);
+  p += strlen(p) + 1;
+  return (size_t)(p - lbuf) + strlen(p);
 }
 
 /// Parse a line from a matching tag.  Does not change the line itself.
@@ -2550,18 +2715,17 @@ static size_t matching_line_len(const char_u *const lbuf)
 /// @param tagp  output: pointers into the line
 ///
 /// @return  OK or FAIL.
-static int parse_match(char_u *lbuf, tagptrs_T *tagp)
+static int parse_match(char *lbuf, tagptrs_T *tagp)
 {
   int retval;
-  char_u *p;
-  char_u *pc, *pt;
+  char *p;
+  char *pc, *pt;
 
   tagp->tag_fname = lbuf + 1;
-  lbuf += STRLEN(tagp->tag_fname) + 2;
+  lbuf += strlen(tagp->tag_fname) + 2;
 
   // Find search pattern and the file name for non-etags.
-  retval = parse_tag_line(lbuf,
-                          tagp);
+  retval = parse_tag_line(lbuf, tagp);
 
   tagp->tagkind = NULL;
   tagp->user_data = NULL;
@@ -2580,20 +2744,20 @@ static int parse_match(char_u *lbuf, tagptrs_T *tagp)
       if (*p++ == TAB) {
         // Accept ASCII alphabetic kind characters and any multi-byte
         // character.
-        while (ASCII_ISALPHA(*p) || utfc_ptr2len((char *)p) > 1) {
-          if (STRNCMP(p, "kind:", 5) == 0) {
+        while (ASCII_ISALPHA(*p) || utfc_ptr2len(p) > 1) {
+          if (strncmp(p, "kind:", 5) == 0) {
             tagp->tagkind = p + 5;
-          } else if (STRNCMP(p, "user_data:", 10) == 0) {
+          } else if (strncmp(p, "user_data:", 10) == 0) {
             tagp->user_data = p + 10;
-          } else if (STRNCMP(p, "line:", 5) == 0) {
-            tagp->tagline = atoi((char *)p + 5);
+          } else if (strncmp(p, "line:", 5) == 0) {
+            tagp->tagline = atoi(p + 5);
           }
           if (tagp->tagkind != NULL && tagp->user_data != NULL) {
             break;
           }
 
-          pc = (char_u *)vim_strchr((char *)p, ':');
-          pt = (char_u *)vim_strchr((char *)p, '\t');
+          pc = vim_strchr(p, ':');
+          pt = vim_strchr(p, '\t');
           if (pc == NULL || (pt != NULL && pc > pt)) {
             tagp->tagkind = p;
           }
@@ -2621,17 +2785,15 @@ static int parse_match(char_u *lbuf, tagptrs_T *tagp)
   return retval;
 }
 
-/*
- * Find out the actual file name of a tag.  Concatenate the tags file name
- * with the matching tag file name.
- * Returns an allocated string.
- */
-static char_u *tag_full_fname(tagptrs_T *tagp)
+// Find out the actual file name of a tag.  Concatenate the tags file name
+// with the matching tag file name.
+// Returns an allocated string.
+static char *tag_full_fname(tagptrs_T *tagp)
 {
-  int c = *tagp->fname_end;
+  char c = *tagp->fname_end;
   *tagp->fname_end = NUL;
-  char_u *fullname = expand_tag_fname(tagp->fname, tagp->tag_fname, false);
-  *tagp->fname_end = (char_u)c;
+  char *fullname = expand_tag_fname(tagp->fname, tagp->tag_fname, false);
+  *tagp->fname_end = c;
 
   return fullname;
 }
@@ -2640,30 +2802,29 @@ static char_u *tag_full_fname(tagptrs_T *tagp)
 ///
 /// @param lbuf_arg  line from the tags file for this tag
 /// @param forceit  :ta with !
-/// @param keep_help  keep help flag (FALSE for cscope)
+/// @param keep_help  keep help flag
 ///
 /// @return  OK for success, NOTAGFILE when file not found, FAIL otherwise.
-static int jumpto_tag(const char_u *lbuf_arg, int forceit, int keep_help)
+static int jumpto_tag(const char *lbuf_arg, int forceit, int keep_help)
 {
-  int save_magic;
   bool save_p_ws;
   int save_p_scs, save_p_ic;
   linenr_T save_lnum;
-  char_u *str;
-  char_u *pbuf;                    // search pattern buffer
-  char_u *pbuf_end;
-  char_u *tofree_fname = NULL;
-  char_u *fname;
+  char *str;
+  char *pbuf;                    // search pattern buffer
+  char *pbuf_end;
+  char *tofree_fname = NULL;
+  char *fname;
   tagptrs_T tagp;
   int retval = FAIL;
   int getfile_result = GETFILE_UNUSED;
   int search_options;
   win_T *curwin_save = NULL;
-  char_u *full_fname = NULL;
+  char *full_fname = NULL;
   const bool old_KeyTyped = KeyTyped;       // getting the file may reset it
   const int l_g_do_tagpreview = g_do_tagpreview;
   const size_t len = matching_line_len(lbuf_arg) + 1;
-  char_u *lbuf = xmalloc(len);
+  char *lbuf = xmalloc(len);
   memmove(lbuf, lbuf_arg, len);
 
   pbuf = xmalloc(LSIZE);
@@ -2689,9 +2850,7 @@ static int jumpto_tag(const char_u *lbuf_arg, int forceit, int keep_help)
   *pbuf_end = NUL;
 
   {
-    /*
-     * Remove the "<Tab>fieldname:value" stuff; we don't need it here.
-     */
+    // Remove the "<Tab>fieldname:value" stuff; we don't need it here.
     str = pbuf;
     if (find_extra(&str) == OK) {
       pbuf_end = str;
@@ -2699,24 +2858,19 @@ static int jumpto_tag(const char_u *lbuf_arg, int forceit, int keep_help)
     }
   }
 
-  /*
-   * Expand file name, when needed (for environment variables).
-   * If 'tagrelative' option set, may change file name.
-   */
+  // Expand file name, when needed (for environment variables).
+  // If 'tagrelative' option set, may change file name.
   fname = expand_tag_fname(fname, tagp.tag_fname, true);
   tofree_fname = fname;         // free() it later
 
-  /*
-   * Check if the file with the tag exists before abandoning the current
-   * file.  Also accept a file name for which there is a matching BufReadCmd
-   * autocommand event (e.g., http://sys/file).
-   */
+  // Check if the file with the tag exists before abandoning the current
+  // file.  Also accept a file name for which there is a matching BufReadCmd
+  // autocommand event (e.g., http://sys/file).
   if (!os_path_exists(fname)
-      && !has_autocmd(EVENT_BUFREADCMD, (char *)fname,
-                      NULL)) {
+      && !has_autocmd(EVENT_BUFREADCMD, fname, NULL)) {
     retval = NOTAGFILE;
     xfree(nofile_fname);
-    nofile_fname = vim_strsave(fname);
+    nofile_fname = xstrdup(fname);
     goto erret;
   }
 
@@ -2726,19 +2880,15 @@ static int jumpto_tag(const char_u *lbuf_arg, int forceit, int keep_help)
     postponed_split = 0;        // don't split again below
     curwin_save = curwin;       // Save current window
 
-    /*
-     * If we are reusing a window, we may change dir when
-     * entering it (autocommands) so turn the tag filename
-     * into a fullpath
-     */
+    // If we are reusing a window, we may change dir when
+    // entering it (autocommands) so turn the tag filename
+    // into a fullpath
     if (!curwin->w_p_pvw) {
-      full_fname = (char_u *)FullName_save((char *)fname, FALSE);
+      full_fname = FullName_save(fname, false);
       fname = full_fname;
 
-      /*
-       * Make the preview window the current window.
-       * Open a preview window when needed.
-       */
+      // Make the preview window the current window.
+      // Open a preview window when needed.
       prepare_tagpreview(true);
     }
   }
@@ -2746,7 +2896,7 @@ static int jumpto_tag(const char_u *lbuf_arg, int forceit, int keep_help)
   // If it was a CTRL-W CTRL-] command split window now.  For ":tab tag"
   // open a new tab page.
   if (postponed_split && (swb_flags & (SWB_USEOPEN | SWB_USETAB))) {
-    buf_T *const existing_buf = buflist_findname_exp((char *)fname);
+    buf_T *const existing_buf = buflist_findname_exp(fname);
 
     if (existing_buf != NULL) {
       const win_T *wp = NULL;
@@ -2791,7 +2941,7 @@ static int jumpto_tag(const char_u *lbuf_arg, int forceit, int keep_help)
   if (getfile_result == GETFILE_UNUSED) {
     // Careful: getfile() may trigger autocommands and call jumpto_tag()
     // recursively.
-    getfile_result = getfile(0, (char *)fname, NULL, true, (linenr_T)0, forceit);
+    getfile_result = getfile(0, fname, NULL, true, (linenr_T)0, forceit);
   }
   keep_help_flag = false;
 
@@ -2799,41 +2949,37 @@ static int jumpto_tag(const char_u *lbuf_arg, int forceit, int keep_help)
     curwin->w_set_curswant = true;
     postponed_split = 0;
 
-    save_magic = p_magic;
-    p_magic = false;            // always execute with 'nomagic'
+    const optmagic_T save_magic_overruled = magic_overruled;
+    magic_overruled = OPTION_MAGIC_OFF;  // always execute with 'nomagic'
     // Save value of no_hlsearch, jumping to a tag is not a real search
     const bool save_no_hlsearch = no_hlsearch;
 
-    /*
-     * If 'cpoptions' contains 't', store the search pattern for the "n"
-     * command.  If 'cpoptions' does not contain 't', the search pattern
-     * is not stored.
-     */
+    // If 'cpoptions' contains 't', store the search pattern for the "n"
+    // command.  If 'cpoptions' does not contain 't', the search pattern
+    // is not stored.
     if (vim_strchr(p_cpo, CPO_TAGPAT) != NULL) {
       search_options = 0;
     } else {
       search_options = SEARCH_KEEP;
     }
 
-    /*
-     * If the command is a search, try here.
-     *
-     * Reset 'smartcase' for the search, since the search pattern was not
-     * typed by the user.
-     * Only use do_search() when there is a full search command, without
-     * anything following.
-     */
+    // If the command is a search, try here.
+    //
+    // Reset 'smartcase' for the search, since the search pattern was not
+    // typed by the user.
+    // Only use do_search() when there is a full search command, without
+    // anything following.
     str = pbuf;
     if (pbuf[0] == '/' || pbuf[0] == '?') {
-      str = skip_regexp(pbuf + 1, pbuf[0], FALSE, NULL) + 1;
+      str = skip_regexp(pbuf + 1, pbuf[0], false) + 1;
     }
     if (str > pbuf_end - 1) {   // search command with nothing following
       save_p_ws = p_ws;
       save_p_ic = p_ic;
       save_p_scs = p_scs;
       p_ws = true;              // need 'wrapscan' for backward searches
-      p_ic = FALSE;             // don't ignore case now
-      p_scs = FALSE;
+      p_ic = false;             // don't ignore case now
+      p_scs = false;
       save_lnum = curwin->w_cursor.lnum;
       if (tagp.tagline > 0) {
         // start search before line from "line:" field
@@ -2847,11 +2993,9 @@ static int jumpto_tag(const char_u *lbuf_arg, int forceit, int keep_help)
         retval = OK;
       } else {
         int found = 1;
-        int cc;
+        char cc;
 
-        /*
-         * try again, ignore case now
-         */
+        // try again, ignore case now
         p_ic = true;
         if (!do_search(NULL, pbuf[0], pbuf[0], pbuf + 1, (long)1,
                        search_options, NULL)) {
@@ -2860,26 +3004,23 @@ static int jumpto_tag(const char_u *lbuf_arg, int forceit, int keep_help)
           (void)test_for_static(&tagp);
           cc = *tagp.tagname_end;
           *tagp.tagname_end = NUL;
-          snprintf((char *)pbuf, LSIZE, "^%s\\s\\*(", tagp.tagname);
+          snprintf(pbuf, LSIZE, "^%s\\s\\*(", tagp.tagname);
           if (!do_search(NULL, '/', '/', pbuf, (long)1, search_options, NULL)) {
             // Guess again: "^char * \<func  ("
-            snprintf((char *)pbuf, LSIZE, "^\\[#a-zA-Z_]\\.\\*\\<%s\\s\\*(",
+            snprintf(pbuf, LSIZE, "^\\[#a-zA-Z_]\\.\\*\\<%s\\s\\*(",
                      tagp.tagname);
-            if (!do_search(NULL, '/', '/', pbuf, (long)1,
-                           search_options, NULL)) {
+            if (!do_search(NULL, '/', '/', pbuf, (long)1, search_options, NULL)) {
               found = 0;
             }
           }
-          *tagp.tagname_end = (char_u)cc;
+          *tagp.tagname_end = cc;
         }
         if (found == 0) {
           emsg(_("E434: Can't find tag pattern"));
           curwin->w_cursor.lnum = save_lnum;
         } else {
-          /*
-           * Only give a message when really guessed, not when 'ic'
-           * is set and match found while ignoring case.
-           */
+          // Only give a message when really guessed, not when 'ic'
+          // is set and match found while ignoring case.
           if (found == 2 || !save_p_ic) {
             msg(_("E435: Couldn't find tag, just guessing!"));
             if (!msg_scrolled && msg_silent == 0) {
@@ -2904,7 +3045,7 @@ static int jumpto_tag(const char_u *lbuf_arg, int forceit, int keep_help)
       secure = 1;
       sandbox++;
       curwin->w_cursor.lnum = 1;  // start command in line 1
-      do_cmdline_cmd((char *)pbuf);
+      do_cmdline_cmd(pbuf);
       retval = OK;
 
       // When the command has done something that is not allowed make sure
@@ -2916,7 +3057,7 @@ static int jumpto_tag(const char_u *lbuf_arg, int forceit, int keep_help)
       sandbox--;
     }
 
-    p_magic = save_magic;
+    magic_overruled = save_magic_overruled;
     // restore no_hlsearch when keeping the old search pattern
     if (search_options) {
       set_no_hlsearch(save_no_hlsearch);
@@ -2928,10 +3069,8 @@ static int jumpto_tag(const char_u *lbuf_arg, int forceit, int keep_help)
     }
 
     if (retval == OK) {
-      /*
-       * For a help buffer: Put the cursor line at the top of the window,
-       * the help subject will be below it.
-       */
+      // For a help buffer: Put the cursor line at the top of the window,
+      // the help subject will be below it.
       if (curbuf->b_help) {
         set_topline(curwin, curwin->w_cursor.lnum);
       }
@@ -2944,7 +3083,7 @@ static int jumpto_tag(const char_u *lbuf_arg, int forceit, int keep_help)
         && curwin != curwin_save && win_valid(curwin_save)) {
       // Return cursor to where we were
       validate_cursor();
-      redraw_later(curwin, VALID);
+      redraw_later(curwin, UPD_VALID);
       win_enter(curwin_save, true);
     }
 
@@ -2967,19 +3106,18 @@ erret:
   return retval;
 }
 
-// If "expand" is true, expand wildcards in fname.
-// If 'tagrelative' option set, change fname (name of file containing tag)
-// according to tag_fname (name of tag file containing fname).
-// Returns a pointer to allocated memory.
-static char_u *expand_tag_fname(char_u *fname, char_u *const tag_fname, const bool expand)
+/// If "expand" is true, expand wildcards in fname.
+/// If 'tagrelative' option set, change fname (name of file containing tag)
+/// according to tag_fname (name of tag file containing fname).
+///
+/// @return  a pointer to allocated memory.
+static char *expand_tag_fname(char *fname, char *const tag_fname, const bool expand)
 {
-  char_u *p;
-  char_u *expanded_fname = NULL;
+  char *p;
+  char *expanded_fname = NULL;
   expand_T xpc;
 
-  /*
-   * Expand file name (for environment variables) when needed.
-   */
+  // Expand file name (for environment variables) when needed.
   if (expand && path_has_wildcard(fname)) {
     ExpandInit(&xpc);
     xpc.xp_context = EXPAND_FILES;
@@ -2990,20 +3128,17 @@ static char_u *expand_tag_fname(char_u *fname, char_u *const tag_fname, const bo
     }
   }
 
-  char_u *retval;
+  char *retval;
   if ((p_tr || curbuf->b_help)
       && !vim_isAbsName(fname)
-      && (p = (char_u *)path_tail((char *)tag_fname)) != tag_fname) {
+      && (p = path_tail(tag_fname)) != tag_fname) {
     retval = xmalloc(MAXPATHL);
     STRCPY(retval, tag_fname);
-    STRLCPY(retval + (p - tag_fname), fname,
-            MAXPATHL - (p - tag_fname));
-    /*
-     * Translate names like "src/a/../b/file.c" into "src/b/file.c".
-     */
+    xstrlcpy(retval + (p - tag_fname), fname, (size_t)(MAXPATHL - (p - tag_fname)));
+    // Translate names like "src/a/../b/file.c" into "src/b/file.c".
     simplify_filename(retval);
   } else {
-    retval = vim_strsave(fname);
+    retval = xstrdup(fname);
   }
 
   xfree(expanded_fname);
@@ -3011,47 +3146,43 @@ static char_u *expand_tag_fname(char_u *fname, char_u *const tag_fname, const bo
   return retval;
 }
 
-/*
- * Check if we have a tag for the buffer with name "buf_ffname".
- * This is a bit slow, because of the full path compare in path_full_compare().
- * Return TRUE if tag for file "fname" if tag file "tag_fname" is for current
- * file.
- */
-static int test_for_current(char_u *fname, char_u *fname_end, char_u *tag_fname, char_u *buf_ffname)
+/// Check if we have a tag for the buffer with name "buf_ffname".
+/// This is a bit slow, because of the full path compare in path_full_compare().
+///
+/// @return  true if tag for file "fname" if tag file "tag_fname" is for current
+///          file.
+static int test_for_current(char *fname, char *fname_end, char *tag_fname, char *buf_ffname)
 {
-  int c;
-  int retval = FALSE;
-  char_u *fullname;
+  char c;
+  int retval = false;
 
   if (buf_ffname != NULL) {     // if the buffer has a name
     {
       c = *fname_end;
       *fname_end = NUL;
     }
-    fullname = expand_tag_fname(fname, tag_fname, true);
-    retval = (path_full_compare((char *)fullname, (char *)buf_ffname, true, true) & kEqualFiles);
+    char *fullname = expand_tag_fname(fname, tag_fname, true);
+    retval = (path_full_compare(fullname, buf_ffname, true, true) & kEqualFiles);
     xfree(fullname);
-    *fname_end = (char_u)c;
+    *fname_end = c;
   }
 
   return retval;
 }
 
-/*
- * Find the end of the tagaddress.
- * Return OK if ";\"" is following, FAIL otherwise.
- */
-static int find_extra(char_u **pp)
+// Find the end of the tagaddress.
+// Return OK if ";\"" is following, FAIL otherwise.
+static int find_extra(char **pp)
 {
-  char_u *str = *pp;
-  char_u first_char = **pp;
+  char *str = *pp;
+  char first_char = **pp;
 
   // Repeat for addresses separated with ';'
   for (;;) {
     if (ascii_isdigit(*str)) {
-      str = (char_u *)skipdigits((char *)str + 1);
+      str = skipdigits(str + 1);
     } else if (*str == '/' || *str == '?') {
-      str = skip_regexp(str + 1, *str, false, NULL);
+      str = skip_regexp(str + 1, *str, false);
       if (*str != first_char) {
         str = NULL;
       } else {
@@ -3059,7 +3190,7 @@ static int find_extra(char_u **pp)
       }
     } else {
       // not a line number or search string, look for terminator.
-      str = (char_u *)strstr((char *)str, "|;\"");
+      str = strstr(str, "|;\"");
       if (str != NULL) {
         str++;
         break;
@@ -3073,7 +3204,7 @@ static int find_extra(char_u **pp)
     first_char = *str;
   }
 
-  if (str != NULL && STRNCMP(str, ";\"", 2) == 0) {
+  if (str != NULL && strncmp(str, ";\"", 2) == 0) {
     *pp = str;
     return OK;
   }
@@ -3090,11 +3221,11 @@ static void tagstack_clear_entry(taggy_T *item)
 }
 
 /// @param tagnames  expand tag names
-int expand_tags(int tagnames, char_u *pat, int *num_file, char ***file)
+int expand_tags(int tagnames, char *pat, int *num_file, char ***file)
 {
   int i;
   int extra_flag;
-  char_u *name_buf;
+  char *name_buf;
   size_t name_buf_size = 100;
   tagptrs_T t_p;
   int ret;
@@ -3109,11 +3240,11 @@ int expand_tags(int tagnames, char_u *pat, int *num_file, char ***file)
   if (pat[0] == '/') {
     ret = find_tags(pat + 1, num_file, file,
                     TAG_REGEXP | extra_flag | TAG_VERBOSE | TAG_NO_TAGFUNC,
-                    TAG_MANY, (char_u *)curbuf->b_ffname);
+                    TAG_MANY, curbuf->b_ffname);
   } else {
     ret = find_tags(pat, num_file, file,
                     TAG_REGEXP | extra_flag | TAG_VERBOSE | TAG_NO_TAGFUNC | TAG_NOIC,
-                    TAG_MANY, (char_u *)curbuf->b_ffname);
+                    TAG_MANY, curbuf->b_ffname);
   }
   if (ret == OK && !tagnames) {
     // Reorganize the tags for display and matching as strings of:
@@ -3121,10 +3252,10 @@ int expand_tags(int tagnames, char_u *pat, int *num_file, char ***file)
     for (i = 0; i < *num_file; i++) {
       size_t len;
 
-      parse_match((char_u *)(*file)[i], &t_p);
+      parse_match((*file)[i], &t_p);
       len = (size_t)(t_p.tagname_end - t_p.tagname);
       if (len > name_buf_size - 3) {
-        char_u *buf;
+        char *buf;
 
         name_buf_size = len + 3;
         buf = xrealloc(name_buf, name_buf_size);
@@ -3150,8 +3281,7 @@ int expand_tags(int tagnames, char_u *pat, int *num_file, char ***file)
 ///
 /// @param start  start of the value
 /// @param end  after the value; can be NULL
-static int add_tag_field(dict_T *dict, const char *field_name, const char_u *start,
-                         const char_u *end)
+static int add_tag_field(dict_T *dict, const char *field_name, const char *start, const char *end)
   FUNC_ATTR_NONNULL_ARG(1, 2)
 {
   int len = 0;
@@ -3166,10 +3296,10 @@ static int add_tag_field(dict_T *dict, const char *field_name, const char_u *sta
     }
     return FAIL;
   }
-  char_u *buf = xmalloc(MAXPATHL);
+  char *buf = xmalloc(MAXPATHL);
   if (start != NULL) {
     if (end == NULL) {
-      end = start + STRLEN(start);
+      end = start + strlen(start);
       while (end > start && (end[-1] == '\r' || end[-1] == '\n')) {
         end--;
       }
@@ -3178,22 +3308,21 @@ static int add_tag_field(dict_T *dict, const char *field_name, const char_u *sta
     if (len > MAXPATHL - 1) {
       len = MAXPATHL - 1;
     }
-    STRLCPY(buf, start, len + 1);
+    xstrlcpy(buf, start, (size_t)len + 1);
   }
   buf[len] = NUL;
-  retval = tv_dict_add_str(dict, field_name, STRLEN(field_name),
-                           (const char *)buf);
+  retval = tv_dict_add_str(dict, field_name, strlen(field_name), buf);
   xfree(buf);
   return retval;
 }
 
 /// Add the tags matching the specified pattern "pat" to the list "list"
 /// as a dictionary. Use "buf_fname" for priority, unless NULL.
-int get_tags(list_T *list, char_u *pat, char_u *buf_fname)
+int get_tags(list_T *list, char *pat, char *buf_fname)
 {
   int num_matches, i, ret;
   char **matches;
-  char_u *full_fname;
+  char *full_fname;
   dict_T *dict;
   tagptrs_T tp;
   bool is_static;
@@ -3202,7 +3331,7 @@ int get_tags(list_T *list, char_u *pat, char_u *buf_fname)
                   TAG_REGEXP | TAG_NOIC, MAXCOL, buf_fname);
   if (ret == OK && num_matches > 0) {
     for (i = 0; i < num_matches; i++) {
-      int parse_result = parse_match((char_u *)matches[i], &tp);
+      int parse_result = parse_match(matches[i], &tp);
 
       // Avoid an unused variable warning in release builds.
       (void)parse_result;
@@ -3211,7 +3340,7 @@ int get_tags(list_T *list, char_u *pat, char_u *buf_fname)
       is_static = test_for_static(&tp);
 
       // Skip pseudo-tag lines.
-      if (STRNCMP(tp.tagname, "!_TAG_", 6) == 0) {
+      if (strncmp(tp.tagname, "!_TAG_", 6) == 0) {
         xfree(matches[i]);
         continue;
       }
@@ -3232,18 +3361,18 @@ int get_tags(list_T *list, char_u *pat, char_u *buf_fname)
       xfree(full_fname);
 
       if (tp.command_end != NULL) {
-        for (char_u *p = tp.command_end + 3;
+        for (char *p = tp.command_end + 3;
              *p != NUL && *p != '\n' && *p != '\r';
              MB_PTR_ADV(p)) {
           if (p == tp.tagkind
-              || (p + 5 == tp.tagkind && STRNCMP(p, "kind:", 5) == 0)) {
+              || (p + 5 == tp.tagkind && strncmp(p, "kind:", 5) == 0)) {
             // skip "kind:<kind>" and "<kind>"
             p = tp.tagkind_end - 1;
-          } else if (STRNCMP(p, "file:", 5) == 0) {
+          } else if (strncmp(p, "file:", 5) == 0) {
             // skip "file:" (static tag)
             p += 4;
           } else if (!ascii_iswhite(*p)) {
-            char_u *s, *n;
+            char *s, *n;
             int len;
 
             // Add extra field as a dict entry.  Fields are
@@ -3255,17 +3384,17 @@ int get_tags(list_T *list, char_u *pat, char_u *buf_fname)
             len = (int)(p - n);
             if (*p == ':' && len > 0) {
               s = ++p;
-              while (*p != NUL && *p >= ' ') {
+              while (*p != NUL && (uint8_t)(*p) >= ' ') {
                 p++;
               }
               n[len] = NUL;
-              if (add_tag_field(dict, (char *)n, s, p) == FAIL) {
+              if (add_tag_field(dict, n, s, p) == FAIL) {
                 ret = FAIL;
               }
               n[len] = ':';
             } else {
               // Skip field without colon.
-              while (*p != NUL && *p >= ' ') {
+              while (*p != NUL && (uint8_t)(*p) >= ' ') {
                 p++;
               }
             }
@@ -3351,9 +3480,9 @@ static void tagstack_shift(win_T *wp)
   wp->w_tagstacklen--;
 }
 
-// Push a new item to the tag stack
-static void tagstack_push_item(win_T *wp, char_u *tagname, int cur_fnum, int cur_match, pos_T mark,
-                               int fnum, char_u *user_data)
+/// Push a new item to the tag stack
+static void tagstack_push_item(win_T *wp, char *tagname, int cur_fnum, int cur_match, pos_T mark,
+                               int fnum, char *user_data)
 {
   taggy_T *tagstack = wp->w_tagstack;
   int idx = wp->w_tagstacklen;  // top of the stack
@@ -3376,13 +3505,13 @@ static void tagstack_push_item(win_T *wp, char_u *tagname, int cur_fnum, int cur
   tagstack[idx].user_data = user_data;
 }
 
-// Add a list of items to the tag stack in the specified window
+/// Add a list of items to the tag stack in the specified window
 static void tagstack_push_items(win_T *wp, list_T *l)
 {
   listitem_T *li;
   dictitem_T *di;
   dict_T *itemdict;
-  char_u *tagname;
+  char *tagname;
   pos_T mark;
   int fnum;
 
@@ -3401,8 +3530,7 @@ static void tagstack_push_items(win_T *wp, list_T *l)
     if (list2fpos(&di->di_tv, &mark, &fnum, NULL, false) != OK) {
       continue;
     }
-    if ((tagname = (char_u *)tv_dict_get_string(itemdict, "tagname", true))
-        == NULL) {
+    if ((tagname = tv_dict_get_string(itemdict, "tagname", true)) == NULL) {
       continue;
     }
 
@@ -3414,7 +3542,7 @@ static void tagstack_push_items(win_T *wp, list_T *l)
                        (int)tv_dict_get_number(itemdict, "bufnr"),
                        (int)tv_dict_get_number(itemdict, "matchnr") - 1,
                        mark, fnum,
-                       (char_u *)tv_dict_get_string(itemdict, "user_data", true));
+                       tv_dict_get_string(itemdict, "user_data", true));
   }
 }
 
@@ -3459,10 +3587,12 @@ int set_tagstack(win_T *wp, const dict_T *d, int action)
   if ((di = tv_dict_find(d, "curidx", -1)) != NULL) {
     tagstack_set_curidx(wp, (int)tv_get_number(&di->di_tv) - 1);
   }
+
   if (action == 't') {  // truncate the stack
     taggy_T *const tagstack = wp->w_tagstack;
     const int tagstackidx = wp->w_tagstackidx;
     int tagstacklen = wp->w_tagstacklen;
+
     // delete all the tag stack entries above the current entry
     while (tagstackidx < tagstacklen) {
       tagstack_clear_entry(&tagstack[--tagstacklen]);