Commit 952f94c8ab48cd22b8eca8d83320bbeec9680419
2012-03-30T14:42:23
Fix bug when join_n refers to original buffer There was a bug in git_buf_join_n when the contents of the original buffer were joined into itself and the realloc moved the pointer to the original buffer.
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diff --git a/src/buffer.c b/src/buffer.c
index ec0302b..c238035 100644
--- a/src/buffer.c
+++ b/src/buffer.c
@@ -256,8 +256,8 @@ int git_buf_join_n(git_buf *buf, char separator, int nbuf, ...)
{
va_list ap;
int i;
- size_t total_size = 0;
- char *out;
+ size_t total_size = 0, original_size = buf->size;
+ char *out, *original = buf->ptr;
if (buf->size > 0 && buf->ptr[buf->size - 1] != separator)
++total_size; /* space for initial separator */
@@ -281,8 +281,9 @@ int git_buf_join_n(git_buf *buf, char separator, int nbuf, ...)
va_end(ap);
/* expand buffer if needed */
- if (total_size > 0 &&
- git_buf_grow(buf, buf->size + total_size + 1) < 0)
+ if (total_size == 0)
+ return 0;
+ if (git_buf_grow(buf, buf->size + total_size + 1) < 0)
return -1;
out = buf->ptr + buf->size;
@@ -300,12 +301,23 @@ int git_buf_join_n(git_buf *buf, char separator, int nbuf, ...)
if (!segment)
continue;
+ /* deal with join that references buffer's original content */
+ if (segment >= original && segment < original + original_size) {
+ size_t offset = (segment - original);
+ segment = buf->ptr + offset;
+ segment_len = original_size - offset;
+ } else {
+ segment_len = strlen(segment);
+ }
+
/* skip leading separators */
if (out > buf->ptr && out[-1] == separator)
- while (*segment == separator) segment++;
+ while (segment_len > 0 && *segment == separator) {
+ segment++;
+ segment_len--;
+ }
/* copy over next buffer */
- segment_len = strlen(segment);
if (segment_len > 0) {
memmove(out, segment, segment_len);
out += segment_len;