From 42f4a5081e06793be6c807d50cd7ec0a83bbcdf1 Mon Sep 17 00:00:00 2001 From: Florian Pritz Date: Mon, 27 Jan 2014 23:38:49 +0100 Subject: util: Add _alpm_realloc() and _alpm_greedy_grow() These will be used in the following patches. Signed-off-by: Florian Pritz --- lib/libalpm/util.c | 62 ++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 62 insertions(+) (limited to 'lib/libalpm/util.c') diff --git a/lib/libalpm/util.c b/lib/libalpm/util.c index 150b85ea..1bc208c6 100644 --- a/lib/libalpm/util.c +++ b/lib/libalpm/util.c @@ -1287,6 +1287,68 @@ int _alpm_fnmatch(const void *pattern, const void *string) return fnmatch(pattern, string, 0); } +/** Think of this as realloc with error handling. If realloc fails NULL will be + * returned and data will not be changed. + * + * Newly created memory will be zeroed. + * + * @param data source memory space + * @param current size of the space pointed to by data + * @param required size you want + * @return new memory; NULL on error + */ +void *_alpm_realloc(void **data, size_t *current, const size_t required) +{ + char *newdata; + + newdata = realloc(*data, required); + if(!newdata) { + _alpm_alloc_fail(required); + return NULL; + } + + if (*current < required) { + /* ensure all new memory is zeroed out, in both the initial + * allocation and later reallocs */ + memset(newdata + *current, 0, required - *current); + } + *current = required; + *data = newdata; + return newdata; +} + +/** This automatically grows data based on current/required. + * + * The memory space will be initialised to required bytes and doubled in size when required. + * + * Newly created memory will be zeroed. + * @param data source memory space + * @param current size of the space pointed to by data + * @param required size you want + * @return new memory if grown; old memory otherwise; NULL on error + */ +void *_alpm_greedy_grow(void **data, size_t *current, const size_t required) +{ + size_t newsize = 0; + + if(*current >= required) { + return data; + } + + if(*current == 0) { + newsize = required; + } else { + newsize = *current * 2; + } + + /* check for overflows */ + if (newsize < required) { + return NULL; + } + + return _alpm_realloc(data, current, required); +} + void _alpm_alloc_fail(size_t size) { fprintf(stderr, "alloc failure: could not allocate %zd bytes\n", size); -- cgit v1.2.3-24-g4f1b