[PATCH v2 01/10] string-list: allow case-insensitive string list

[Junio C Hamano]

Some string list needs to be searched case insensitively, and for
that to work correctly, the string needs to be sorted case
insensitively from the beginning.

Allow a custom comparison function to be defined on a string list
instance and use it throughout in place of strcmp().

Signed-off-by: Junio C Hamano <gits...@pobox.com>
---
 string-list.c | 17 +++++++++++++----
 string-list.h |  4 ++++
 2 files changed, 17 insertions(+), 4 deletions(-)

diff --git a/string-list.c b/string-list.c
index 397e6cf..6f3d8cf 100644
--- a/string-list.c
+++ b/string-list.c
@@ -7,10 +7,11 @@ static int get_entry_index(const struct string_list *list, 
const char *string,
                int *exact_match)
 {
        int left = -1, right = list->nr;
+       compare_strings_fn cmp = list->cmp ? list->cmp : strcmp;
 
        while (left + 1 < right) {
                int middle = (left + right) / 2;
-               int compare = strcmp(string, list->items[middle].string);
+               int compare = cmp(string, list->items[middle].string);
                if (compare < 0)
                        right = middle;
                else if (compare > 0)
@@ -96,8 +97,9 @@ void string_list_remove_duplicates(struct string_list *list, 
int free_util)
 {
        if (list->nr > 1) {
                int src, dst;
+               compare_strings_fn cmp = list->cmp ? list->cmp : strcmp;
                for (src = dst = 1; src < list->nr; src++) {
-                       if (!strcmp(list->items[dst - 1].string, 
list->items[src].string)) {
+                       if (!cmp(list->items[dst - 1].string, 
list->items[src].string)) {
                                if (list->strdup_strings)
                                        free(list->items[src].string);
                                if (free_util)
@@ -230,15 +232,20 @@ struct string_list_item *string_list_append(struct 
string_list *list,
                        list->strdup_strings ? xstrdup(string) : (char 
*)string);
 }
 
+/* Yuck */
+static compare_strings_fn compare_for_qsort;
+
+/* Only call this from inside sort_string_list! */
 static int cmp_items(const void *a, const void *b)
 {
        const struct string_list_item *one = a;
        const struct string_list_item *two = b;
-       return strcmp(one->string, two->string);
+       return compare_for_qsort(one->string, two->string);
 }
 
 void sort_string_list(struct string_list *list)
 {
+       compare_for_qsort = list->cmp ? list->cmp : strcmp;
        qsort(list->items, list->nr, sizeof(*list->items), cmp_items);
 }
 
@@ -246,8 +253,10 @@ struct string_list_item 
*unsorted_string_list_lookup(struct string_list *list,
                                                     const char *string)
 {
        int i;
+       compare_strings_fn cmp = list->cmp ? list->cmp : strcmp;
+
        for (i = 0; i < list->nr; i++)
-               if (!strcmp(string, list->items[i].string))
+               if (!cmp(string, list->items[i].string))
                        return list->items + i;
        return NULL;
 }
diff --git a/string-list.h b/string-list.h
index c50b0d0..446e79e 100644
--- a/string-list.h
+++ b/string-list.h
@@ -5,10 +5,14 @@ struct string_list_item {
        char *string;
        void *util;
 };
+
+typedef int (*compare_strings_fn)(const char *, const char *);
+
 struct string_list {
        struct string_list_item *items;
        unsigned int nr, alloc;
        unsigned int strdup_strings:1;
+       compare_strings_fn cmp; /* NULL uses strcmp() */
 };
 
 #define STRING_LIST_INIT_NODUP { NULL, 0, 0, 0 }
-- 
1.8.1.304.gf036638

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