Signed-off-by: Florian Pritz
---
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