Signed-off-by: Florian Pritz <bluewind@xinu.at> --- v3: Implement suggestions from Andrew RFC from v2 still holds: is using char for *newdata fine or is there any good reason to use uint8_t like systemd does? lib/libalpm/util.c | 49 +++++++++++++++++++++++++++++++++++++++++++++++++ lib/libalpm/util.h | 1 + 2 files changed, 50 insertions(+) diff --git a/lib/libalpm/util.c b/lib/libalpm/util.c index 150b85e..28b8646 100644 --- a/lib/libalpm/util.c +++ b/lib/libalpm/util.c @@ -1287,6 +1287,55 @@ int _alpm_fnmatch(const void *pattern, const void *string) return fnmatch(pattern, string, 0); } +/** + * Think of this as realloc with error handling and + * automatic growing based on current/required. + * + * data will point to a memory space with at least required + * bytes, likely more. You may want to free unused memory. + * If required < current data is returned and nothing happens. + * + * @param data source memory space + * @param current size of the space pointed to be data + * @param required size you want + * @return new memory if grown; old memory otherwise; NULL on error + */ +void *_alpm_realloc(void **data, size_t *current, const size_t required) +{ + char *newdata; + size_t newsize = 0; + + if(*current >= required) { + return data; + } + + if(*current == 0) { + newsize = ALPM_BUFFER_SIZE; + } else if (required > (*current) * 2) { + newsize = required * 2; + } else { + newsize = *current * 2; + } + + /* check for overflows */ + if (newsize < required) { + return NULL; + } + + newdata = realloc(*data, newsize); + if(!newdata) { + _alpm_alloc_fail(newsize); + return NULL; + } + + /* ensure all new memory is zeroed out, in both the initial + * allocation and later reallocs */ + memset(newdata + *current, 0, newsize - *current); + *current = newsize; + *data = newdata; + return newdata; +} + void _alpm_alloc_fail(size_t size) { fprintf(stderr, "alloc failure: could not allocate %zd bytes\n", size); diff --git a/lib/libalpm/util.h b/lib/libalpm/util.h index 250c530..f348540 100644 --- a/lib/libalpm/util.h +++ b/lib/libalpm/util.h @@ -141,6 +141,7 @@ int _alpm_raw_ncmp(const char *first, const char *second, size_t max); int _alpm_access(alpm_handle_t *handle, const char *dir, const char *file, int amode); int _alpm_fnmatch_patterns(alpm_list_t *patterns, const char *string); int _alpm_fnmatch(const void *pattern, const void *string); +void *_alpm_realloc(void **data, size_t *current, const size_t required); #ifndef HAVE_STRSEP char *strsep(char **, const char *); -- 1.8.5.3