midx: double-check large object write loop
The write_midx_large_offsets() function takes an array of object entries, the number of entries in the array (nr_objects), and the number of entries with large offsets (nr_large_offset). But we never actually use nr_objects; instead we keep walking down the array and counting down nr_large_offset until we've seen all of the large entries. This is correct, but we can be a bit more defensive. If there were ever a mismatch between nr_large_offset and the actual set of large-offset objects, we'd walk off the end of the array. Since we know the size of the array, we can use nr_objects to make sure we don't walk too far. Signed-off-by: Jeff King <peff@peff.net> Reviewed-by: Derrick Stolee <dstolee@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>maint
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							|  | @ -712,12 +712,18 @@ static size_t write_midx_object_offsets(struct hashfile *f, int large_offset_nee | ||||||
| static size_t write_midx_large_offsets(struct hashfile *f, uint32_t nr_large_offset, | static size_t write_midx_large_offsets(struct hashfile *f, uint32_t nr_large_offset, | ||||||
| 				       struct pack_midx_entry *objects, uint32_t nr_objects) | 				       struct pack_midx_entry *objects, uint32_t nr_objects) | ||||||
| { | { | ||||||
| 	struct pack_midx_entry *list = objects; | 	struct pack_midx_entry *list = objects, *end = objects + nr_objects; | ||||||
| 	size_t written = 0; | 	size_t written = 0; | ||||||
|  |  | ||||||
| 	while (nr_large_offset) { | 	while (nr_large_offset) { | ||||||
| 		struct pack_midx_entry *obj = list++; | 		struct pack_midx_entry *obj; | ||||||
| 		uint64_t offset = obj->offset; | 		uint64_t offset; | ||||||
|  |  | ||||||
|  | 		if (list >= end) | ||||||
|  | 			BUG("too many large-offset objects"); | ||||||
|  |  | ||||||
|  | 		obj = list++; | ||||||
|  | 		offset = obj->offset; | ||||||
|  |  | ||||||
| 		if (!(offset >> 31)) | 		if (!(offset >> 31)) | ||||||
| 			continue; | 			continue; | ||||||
|  |  | ||||||
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