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19716b21a4
A common mistake when writing binary search is to allow possible integer overflow by using the simple average: mid = (min + max) / 2; Instead, use the overflow-safe version: mid = min + (max - min) / 2; This translation is safe since the operation occurs inside a loop conditioned on "min < max". The included changes were found using the following git grep: git grep '/ *2;' '*.c' Making this cleanup will prevent future review friction when a new binary search is contructed based on existing code. Signed-off-by: Derrick Stolee <dstolee@microsoft.com> Reviewed-by: Jeff King <peff@peff.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>
321 lines
7.5 KiB
C
321 lines
7.5 KiB
C
#include "cache.h"
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#include "string-list.h"
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void string_list_init(struct string_list *list, int strdup_strings)
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{
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memset(list, 0, sizeof(*list));
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list->strdup_strings = strdup_strings;
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}
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/* if there is no exact match, point to the index where the entry could be
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* inserted */
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static int get_entry_index(const struct string_list *list, const char *string,
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int *exact_match)
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{
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int left = -1, right = list->nr;
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compare_strings_fn cmp = list->cmp ? list->cmp : strcmp;
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while (left + 1 < right) {
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int middle = left + (right - left) / 2;
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int compare = cmp(string, list->items[middle].string);
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if (compare < 0)
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right = middle;
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else if (compare > 0)
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left = middle;
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else {
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*exact_match = 1;
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return middle;
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}
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}
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*exact_match = 0;
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return right;
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}
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/* returns -1-index if already exists */
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static int add_entry(int insert_at, struct string_list *list, const char *string)
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{
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int exact_match = 0;
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int index = insert_at != -1 ? insert_at : get_entry_index(list, string, &exact_match);
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if (exact_match)
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return -1 - index;
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ALLOC_GROW(list->items, list->nr+1, list->alloc);
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if (index < list->nr)
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MOVE_ARRAY(list->items + index + 1, list->items + index,
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list->nr - index);
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list->items[index].string = list->strdup_strings ?
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xstrdup(string) : (char *)string;
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list->items[index].util = NULL;
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list->nr++;
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return index;
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}
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struct string_list_item *string_list_insert(struct string_list *list, const char *string)
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{
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int index = add_entry(-1, list, string);
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if (index < 0)
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index = -1 - index;
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return list->items + index;
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}
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void string_list_remove(struct string_list *list, const char *string,
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int free_util)
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{
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int exact_match;
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int i = get_entry_index(list, string, &exact_match);
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if (exact_match) {
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if (list->strdup_strings)
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free(list->items[i].string);
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if (free_util)
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free(list->items[i].util);
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list->nr--;
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MOVE_ARRAY(list->items + i, list->items + i + 1, list->nr - i);
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}
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}
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int string_list_has_string(const struct string_list *list, const char *string)
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{
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int exact_match;
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get_entry_index(list, string, &exact_match);
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return exact_match;
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}
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int string_list_find_insert_index(const struct string_list *list, const char *string,
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int negative_existing_index)
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{
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int exact_match;
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int index = get_entry_index(list, string, &exact_match);
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if (exact_match)
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index = -1 - (negative_existing_index ? index : 0);
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return index;
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}
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struct string_list_item *string_list_lookup(struct string_list *list, const char *string)
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{
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int exact_match, i = get_entry_index(list, string, &exact_match);
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if (!exact_match)
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return NULL;
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return list->items + i;
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}
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void string_list_remove_duplicates(struct string_list *list, int free_util)
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{
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if (list->nr > 1) {
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int src, dst;
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compare_strings_fn cmp = list->cmp ? list->cmp : strcmp;
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for (src = dst = 1; src < list->nr; src++) {
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if (!cmp(list->items[dst - 1].string, list->items[src].string)) {
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if (list->strdup_strings)
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free(list->items[src].string);
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if (free_util)
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free(list->items[src].util);
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} else
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list->items[dst++] = list->items[src];
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}
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list->nr = dst;
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}
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}
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int for_each_string_list(struct string_list *list,
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string_list_each_func_t fn, void *cb_data)
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{
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int i, ret = 0;
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for (i = 0; i < list->nr; i++)
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if ((ret = fn(&list->items[i], cb_data)))
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break;
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return ret;
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}
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void filter_string_list(struct string_list *list, int free_util,
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string_list_each_func_t want, void *cb_data)
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{
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int src, dst = 0;
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for (src = 0; src < list->nr; src++) {
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if (want(&list->items[src], cb_data)) {
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list->items[dst++] = list->items[src];
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} else {
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if (list->strdup_strings)
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free(list->items[src].string);
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if (free_util)
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free(list->items[src].util);
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}
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}
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list->nr = dst;
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}
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static int item_is_not_empty(struct string_list_item *item, void *unused)
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{
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return *item->string != '\0';
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}
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void string_list_remove_empty_items(struct string_list *list, int free_util) {
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filter_string_list(list, free_util, item_is_not_empty, NULL);
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}
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void string_list_clear(struct string_list *list, int free_util)
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{
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if (list->items) {
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int i;
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if (list->strdup_strings) {
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for (i = 0; i < list->nr; i++)
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free(list->items[i].string);
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}
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if (free_util) {
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for (i = 0; i < list->nr; i++)
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free(list->items[i].util);
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}
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free(list->items);
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}
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list->items = NULL;
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list->nr = list->alloc = 0;
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}
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void string_list_clear_func(struct string_list *list, string_list_clear_func_t clearfunc)
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{
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if (list->items) {
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int i;
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if (clearfunc) {
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for (i = 0; i < list->nr; i++)
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clearfunc(list->items[i].util, list->items[i].string);
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}
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if (list->strdup_strings) {
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for (i = 0; i < list->nr; i++)
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free(list->items[i].string);
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}
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free(list->items);
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}
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list->items = NULL;
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list->nr = list->alloc = 0;
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}
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void print_string_list(const struct string_list *p, const char *text)
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{
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int i;
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if ( text )
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printf("%s\n", text);
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for (i = 0; i < p->nr; i++)
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printf("%s:%p\n", p->items[i].string, p->items[i].util);
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}
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struct string_list_item *string_list_append_nodup(struct string_list *list,
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char *string)
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{
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struct string_list_item *retval;
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ALLOC_GROW(list->items, list->nr + 1, list->alloc);
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retval = &list->items[list->nr++];
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retval->string = string;
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retval->util = NULL;
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return retval;
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}
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struct string_list_item *string_list_append(struct string_list *list,
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const char *string)
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{
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return string_list_append_nodup(
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list,
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list->strdup_strings ? xstrdup(string) : (char *)string);
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}
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static int cmp_items(const void *a, const void *b, void *ctx)
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{
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compare_strings_fn cmp = ctx;
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const struct string_list_item *one = a;
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const struct string_list_item *two = b;
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return cmp(one->string, two->string);
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}
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void string_list_sort(struct string_list *list)
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{
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QSORT_S(list->items, list->nr, cmp_items,
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list->cmp ? list->cmp : strcmp);
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}
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struct string_list_item *unsorted_string_list_lookup(struct string_list *list,
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const char *string)
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{
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struct string_list_item *item;
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compare_strings_fn cmp = list->cmp ? list->cmp : strcmp;
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for_each_string_list_item(item, list)
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if (!cmp(string, item->string))
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return item;
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return NULL;
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}
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int unsorted_string_list_has_string(struct string_list *list,
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const char *string)
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{
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return unsorted_string_list_lookup(list, string) != NULL;
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}
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void unsorted_string_list_delete_item(struct string_list *list, int i, int free_util)
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{
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if (list->strdup_strings)
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free(list->items[i].string);
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if (free_util)
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free(list->items[i].util);
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list->items[i] = list->items[list->nr-1];
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list->nr--;
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}
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int string_list_split(struct string_list *list, const char *string,
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int delim, int maxsplit)
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{
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int count = 0;
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const char *p = string, *end;
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if (!list->strdup_strings)
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die("internal error in string_list_split(): "
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"list->strdup_strings must be set");
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for (;;) {
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count++;
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if (maxsplit >= 0 && count > maxsplit) {
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string_list_append(list, p);
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return count;
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}
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end = strchr(p, delim);
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if (end) {
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string_list_append_nodup(list, xmemdupz(p, end - p));
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p = end + 1;
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} else {
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string_list_append(list, p);
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return count;
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}
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}
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}
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int string_list_split_in_place(struct string_list *list, char *string,
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int delim, int maxsplit)
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{
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int count = 0;
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char *p = string, *end;
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if (list->strdup_strings)
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die("internal error in string_list_split_in_place(): "
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"list->strdup_strings must not be set");
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for (;;) {
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count++;
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if (maxsplit >= 0 && count > maxsplit) {
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string_list_append(list, p);
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return count;
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}
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end = strchr(p, delim);
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if (end) {
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*end = '\0';
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string_list_append(list, p);
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p = end + 1;
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} else {
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string_list_append(list, p);
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return count;
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}
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}
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}
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