On Tue, Jan 28, 2014 at 12:02:34AM +0100, Florian Pritz wrote:
Signed-off-by: Florian Pritz <bluewind@xinu.at> --- lib/libalpm/util.c | 38 ++++++++++++++++++++++++++++++++++++++ lib/libalpm/util.h | 1 + 2 files changed, 39 insertions(+)
diff --git a/lib/libalpm/util.c b/lib/libalpm/util.c index 1bbc768..5f99f35 100644 --- a/lib/libalpm/util.c +++ b/lib/libalpm/util.c @@ -1287,6 +1287,44 @@ 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 bases on current/required
Hrmmm, I'm not really a fan of this as is. One might argue that it doesn't really do error handling -- it returns NULL on error (the same as realloc), and merely wraps some semi-arbitrary logic for deciding how much to grow the buffer. The caller still needs to save the value if they want to avoid a crappy situation on OOM. I think we can do better, and I'd suggesting looking greedy_realloc (function and macro) in systemd's codebase (src/shared/util.[ch]). What you have here is close, but a minor switch in the return value and the first parameter makes this a whole lot more useful.
+ * + * @param data source memory space + * @param current size of the space pointed to be data + * @param required size you want + * @return new memory + */ +void *_alpm_realloc(void *data, size_t *current, const size_t required) +{ + if(required >= *current) { + size_t old_size = *current; + char *newdata; + size_t newsize = *current; + + if(*current == 0) { + newsize = ALPM_BUFFER_SIZE; + } else if (required > (*current) * 2) { + newsize = required * 2; + } else { + newsize *= 2; + } + + 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 + old_size, 0, *current - old_size); + *current = newsize; + return newdata; + } + return data; +} + 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 b566868..b7e6e90 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