[PATCH v2 2/4] string-list: replace negative index encoding with "exact_match" parameter
- From
shejialuo <shejialuo@gmail.com>
- Date
- Sep 17, 2025, 09:19 UTC
- Message-ID
- <aMp9OtXLfRw7dEwA@ArchLinux>
- In-Reply-To
- <aMp8yNFiXDyk2hP4@ArchLinux>
We would return negative index to indicate exact match by converting the original positive index to be "-1 - index" in "string_list_find_insert_index", which requires callers to decode this information. This approach has several limitations:
1. It prevents us from using the full range of size_t, which is necessary for large string list. 2. Using int for indices while other parts of the codebase use size_t creates signed comparison warnings when these values are compared.
To address these limitations, change the function to return size_t for the index value and use a separate bool parameter to indicate whether the index refers to an existing entry or an insertion point.
In some cases, the callers of "string_list_find_insert_index" only need the index position and don't care whether an exact match is found. However, "get_entry_index" currently requires a non-NULL "exact_match" parameter, forcing these callers to declare unnecessary variables. Let's allow callers to pass NULL for the "exact_match" parameter when they don't need this information, reducing unnecessary variable declarations in calling code.
Signed-off-by: shejialuo <shejialuo@gmail.com> --- add-interactive.c | 7 ++++--- mailmap.c | 7 +++---- refs.c | 2 +- string-list.c | 14 ++++++-------- string-list.h | 2 +- 5 files changed, 15 insertions(+), 17 deletions(-)
diff --git a/add-interactive.c b/add-interactive.c index 3e692b47ec..7c0fd3d218 100644 --- a/add-interactive.c +++ b/add-interactive.c @@ -221,7 +221,8 @@ static void find_unique_prefixes(struct prefix_item_list *list) static ssize_t find_unique(const char *string, struct prefix_item_list *list) { - int index = string_list_find_insert_index(&list->sorted, string, 1); + bool exact_match; + int index = string_list_find_insert_index(&list->sorted, string, &exact_match); struct string_list_item *item; if (list->items.nr != list->sorted.nr) @@ -229,8 +230,8 @@ static ssize_t find_unique(const char *string, struct prefix_item_list *list) " vs %"PRIuMAX")", (uintmax_t)list->items.nr, (uintmax_t)list->sorted.nr); - if (index < 0) - item = list->sorted.items[-1 - index].util; + if (exact_match) + item = list->sorted.items[index].util; else if (index > 0 && starts_with(list->sorted.items[index - 1].string, string)) return -1; diff --git a/mailmap.c b/mailmap.c index 56c72102d9..58a4484963 100644 --- a/mailmap.c +++ b/mailmap.c @@ -243,10 +243,9 @@ void clear_mailmap(struct string_list *map) static struct string_list_item *lookup_prefix(struct string_list *map, const char *string, size_t len) { - int i = string_list_find_insert_index(map, string, 1); - if (i < 0) { - /* exact match */ - i = -1 - i; + bool exact_match; + int i = string_list_find_insert_index(map, string, &exact_match); + if (exact_match) { if (!string[len]) return &map->items[i]; /* diff --git a/refs.c b/refs.c index 4ff55cf24f..f1ff5bf846 100644 --- a/refs.c +++ b/refs.c @@ -1699,7 +1699,7 @@ const char *find_descendant_ref(const char *dirname, * with dirname (remember, dirname includes the trailing * slash) and is not in skip, then we have a conflict. */ - for (pos = string_list_find_insert_index(extras, dirname, 0); + for (pos = string_list_find_insert_index(extras, dirname, NULL); pos < extras->nr; pos++) { const char *extra_refname = extras->items[pos].string; diff --git a/string-list.c b/string-list.c index d8da3dd414..c589ab5a2c 100644 --- a/string-list.c +++ b/string-list.c @@ -29,12 +29,14 @@ static size_t get_entry_index(const struct string_list *list, const char *string else if (compare > 0) left = middle + 1; else { - *exact_match = true; + if (exact_match) + *exact_match = true; return middle; } } - *exact_match = false; + if (exact_match) + *exact_match = false; return right; } @@ -90,13 +92,9 @@ bool string_list_has_string(const struct string_list *list, const char *string) } int string_list_find_insert_index(const struct string_list *list, const char *string, - int negative_existing_index) + bool *exact_match) { - bool exact_match; - int index = get_entry_index(list, string, &exact_match); - if (exact_match) - index = -1 - (negative_existing_index ? index : 0); - return index; + return get_entry_index(list, string, exact_match); } struct string_list_item *string_list_lookup(struct string_list *list, const char *string) diff --git a/string-list.h b/string-list.h index bc7f38022e..8830ce671d 100644 --- a/string-list.h +++ b/string-list.h @@ -174,7 +174,7 @@ void string_list_remove_empty_items(struct string_list *list, int free_util); /** Determine if the string_list has a given string or not. */ bool string_list_has_string(const struct string_list *list, const char *string); int string_list_find_insert_index(const struct string_list *list, const char *string, - int negative_existing_index); + bool *exact_match); /** * Insert a new element to the string_list. The returned pointer can
-- 2.51.0