vim-patch:9.0.2124: INT overflow detection logic can be simplified

Problem:  INT overflow logic can be simplified
Solution: introduce trim_to_int() function

closes: vim/vim#13556

https://github.com/vim/vim/commit/2b0882fa6555b4d0197afbdfc32a4533cf6aacf4

vim-patch:9.0.2138: Overflow logic requires long long

Problem:  Overflow logic requires long long
Solution: Define vimlong_T data type to make life easier
          for porters

closes: vim/vim#13598

https://github.com/vim/vim/commit/fda700cb04612fe2f9301a9ba820309175decabf

Cherry-pick ops.c change from patch 9.1.0608.

Co-authored-by: Ernie Rael <errael@raelity.com>

3 files changed, 14 insertions, 14 deletions

diff --git a/src/nvim/indent_c.c b/src/nvim/indent_c.c
index 9b5c80dd09..c9b7a1ba3f 100644
--- a/src/nvim/indent_c.c
+++ b/src/nvim/indent_c.c
@@ -14,6 +14,7 @@
 #include "nvim/indent_c.h"
 #include "nvim/macros_defs.h"
 #include "nvim/mark_defs.h"
+#include "nvim/math.h"
 #include "nvim/memline.h"
 #include "nvim/memory.h"
 #include "nvim/option.h"
@@ -1708,7 +1709,7 @@ void parse_cino(buf_T *buf)
       } else {
         n *= sw;
         if (divider) {
-          n += (sw * fraction + divider / 2) / divider;
+          n += ((int64_t)sw * fraction + divider / 2) / divider;
         }
       }
       p++;
@@ -1717,11 +1718,7 @@ void parse_cino(buf_T *buf)
       n = -n;
     }
 
-    if (n > INT_MAX) {
-      n = INT_MAX;
-    } else if (n < INT_MIN) {
-      n = INT_MIN;
-    }
+    n = trim_to_int(n);
 
     // When adding an entry here, also update the default 'cinoptions' in
     // doc/indent.txt, and add explanation for it!
diff --git a/src/nvim/math.c b/src/nvim/math.c
index 4ca212413b..0b5886d36c 100644
--- a/src/nvim/math.c
+++ b/src/nvim/math.c
@@ -106,3 +106,9 @@ int vim_append_digit_int(int *value, int digit)
   *value = x * 10 + digit;
   return OK;
 }
+
+/// Return something that fits into an int.
+int trim_to_int(int64_t x)
+{
+  return x > INT_MAX ? INT_MAX : x < INT_MIN ? INT_MIN : (int)x;
+}
diff --git a/src/nvim/ops.c b/src/nvim/ops.c
index 5325beb654..9524c67301 100644
--- a/src/nvim/ops.c
+++ b/src/nvim/ops.c
@@ -48,6 +48,7 @@
 #include "nvim/macros_defs.h"
 #include "nvim/mark.h"
 #include "nvim/mark_defs.h"
+#include "nvim/math.h"
 #include "nvim/mbyte.h"
 #include "nvim/mbyte_defs.h"
 #include "nvim/memline.h"
@@ -286,8 +287,8 @@ void shift_line(bool left, bool round, int amount, int call_changed_bytes)
   int64_t count = get_indent();  // get current indent
 
   if (round) {  // round off indent
-    int i = (int)(count / sw_val);  // number of 'shiftwidth' rounded down
-    int j = (int)(count % sw_val);  // extra spaces
+    int i = trim_to_int(count / sw_val);  // number of 'shiftwidth' rounded down
+    int j = trim_to_int(count % sw_val);  // extra spaces
     if (j && left) {  // first remove extra spaces
       amount--;
     }
@@ -305,15 +306,11 @@ void shift_line(bool left, bool round, int amount, int call_changed_bytes)
     }
   }
 
-  if (count > INT_MAX) {
-    count = INT_MAX;
-  }
-
   // Set new indent
   if (State & VREPLACE_FLAG) {
-    change_indent(INDENT_SET, (int)count, false, call_changed_bytes);
+    change_indent(INDENT_SET, trim_to_int(count), false, call_changed_bytes);
   } else {
-    set_indent((int)count, call_changed_bytes ? SIN_CHANGED : 0);
+    set_indent(trim_to_int(count), call_changed_bytes ? SIN_CHANGED : 0);
   }
 }