diff options
Diffstat (limited to 'src')
| -rw-r--r-- | src/nvim/ex_getln.c | 98 |
1 files changed, 50 insertions, 48 deletions
diff --git a/src/nvim/ex_getln.c b/src/nvim/ex_getln.c index 5fd5c2a345..9a5da761a5 100644 --- a/src/nvim/ex_getln.c +++ b/src/nvim/ex_getln.c @@ -10,6 +10,7 @@ * ex_getln.c: Functions for entering and editing an Ex command line. */ +#include <assert.h> #include <errno.h> #include <stdbool.h> #include <string.h> @@ -4169,58 +4170,59 @@ static char_u *get_history_arg(expand_T *xp, int idx) return NULL; } -/* - * init_history() - Initialize the command line history. - * Also used to re-allocate the history when the size changes. - */ +/// Initialize command line history. +/// Also used to re-allocate history tables when size changes. void init_history(void) { - /* - * If size of history table changed, reallocate it - */ - ssize_t newlen = p_hi; - if (newlen != hislen) { - histentry_T *temp; - ssize_t i; - ssize_t j; - - // adjust the tables - for (int type = 0; type < HIST_COUNT; ++type) { - if (newlen) { - temp = xmalloc(newlen * sizeof(*temp)); - } else - temp = NULL; - if (newlen == 0 || temp != NULL) { - if (hisidx[type] < 0) { /* there are no entries yet */ - for (i = 0; i < newlen; ++i) - clear_hist_entry(&temp[i]); - } else if (newlen > hislen) { /* array becomes bigger */ - for (i = 0; i <= hisidx[type]; ++i) - temp[i] = history[type][i]; - j = i; - for (; i <= newlen - (hislen - hisidx[type]); ++i) - clear_hist_entry(&temp[i]); - for (; j < hislen; ++i, ++j) - temp[i] = history[type][j]; - } else { /* array becomes smaller or 0 */ - j = hisidx[type]; - for (i = newlen - 1;; --i) { - if (i >= 0) /* copy newest entries */ - temp[i] = history[type][j]; - else { /* remove older entries */ - xfree(history[type][j].hisstr); - history[type][j].hisstr = NULL; - } - if (--j < 0) - j = hislen - 1; - if (j == hisidx[type]) - break; - } - hisidx[type] = newlen - 1; + assert(p_hi >= 0 && p_hi <= INT_MAX); + int newlen = (int)p_hi; + int oldlen = hislen; + + // If history tables size changed, reallocate them. + // Tables are circular arrays (current position marked by hisidx[type]). + // On copying them to the new arrays, we take the chance to reorder them. + if (newlen != oldlen) { + for (int type = 0; type < HIST_COUNT; type++) { + histentry_T *temp = newlen ? xmalloc(newlen * sizeof(*temp)) : NULL; + + int j = hisidx[type]; + if (j >= 0) { + // old array gets partitioned this way: + // [0 , i1 ) --> newest entries to be deleted + // [i1 , i1 + l1) --> newest entries to be copied + // [i1 + l1 , i2 ) --> oldest entries to be deleted + // [i2 , i2 + l2) --> oldest entries to be copied + int l1 = MIN(j + 1, newlen); // how many newest to copy + int l2 = MIN(newlen, oldlen) - l1; // how many oldest to copy + int i1 = j + 1 - l1; // copy newest from here + int i2 = MAX(l1, oldlen - newlen + l1); // copy oldest from here + + // copy as much entries as they fit to new table, reordering them + if (newlen) { + // copy oldest entries + memcpy(&temp[0], &history[type][i2], (size_t)l2 * sizeof(*temp)); + // copy newest entries + memcpy(&temp[l2], &history[type][i1], (size_t)l1 * sizeof(*temp)); + } + + // delete entries that don't fit in newlen, if any + for (int i = 0; i < i1; i++) { + xfree(history[type][i].hisstr); + history[type][i].hisstr = NULL; + } + for (int i = i1 + l1; i < i2; i++) { + xfree(history[type][i].hisstr); + history[type][i].hisstr = NULL; } - xfree(history[type]); - history[type] = temp; } + + // clear remaining space, if any + int l3 = j < 0 ? 0 : MIN(newlen, oldlen); // number of copied entries + memset(temp + l3, 0, (size_t)(newlen - l3) * sizeof(*temp)); + + hisidx[type] = l3 - 1; + xfree(history[type]); + history[type] = temp; } hislen = newlen; } |