pack-objects: reuse data from existing packs.

diff --git a/index-pack.c b/index-pack.c
index d4ce3af5878e6e8d855783002f9d4e3f44af8d05..babe34b2db520a311d6c8ef090383755ba1807c9 100644 (file)
--- a/index-pack.c
+++ b/index-pack.c
@@ -68,9 +68,9 @@ static void parse_pack_header(void)
        hdr = (void *)pack_base;
        if (hdr->hdr_signature != htonl(PACK_SIGNATURE))
                die("packfile '%s' signature mismatch", pack_name);
-       if (hdr->hdr_version != htonl(PACK_VERSION))
-               die("packfile '%s' version %d different from ours %d",
-                   pack_name, ntohl(hdr->hdr_version), PACK_VERSION);
+       if (!pack_version_ok(hdr->hdr_version))
+               die("packfile '%s' version %d unsupported",
+                   pack_name, ntohl(hdr->hdr_version));
 
        nr_objects = ntohl(hdr->hdr_entries);
 
@@ -352,18 +352,24 @@ static int sha1_compare(const void *_a, const void *_b)
 static void write_index_file(const char *index_name, unsigned char *sha1)
 {
        struct sha1file *f;
-       struct object_entry **sorted_by_sha =
-               xcalloc(nr_objects, sizeof(struct object_entry *));
-       struct object_entry **list = sorted_by_sha;
-       struct object_entry **last = sorted_by_sha + nr_objects;
+       struct object_entry **sorted_by_sha, **list, **last;
        unsigned int array[256];
        int i;
        SHA_CTX ctx;
 
-       for (i = 0; i < nr_objects; ++i)
-               sorted_by_sha[i] = &objects[i];
-       qsort(sorted_by_sha, nr_objects, sizeof(sorted_by_sha[0]),
-             sha1_compare);
+       if (nr_objects) {
+               sorted_by_sha =
+                       xcalloc(nr_objects, sizeof(struct object_entry *));
+               list = sorted_by_sha;
+               last = sorted_by_sha + nr_objects;
+               for (i = 0; i < nr_objects; ++i)
+                       sorted_by_sha[i] = &objects[i];
+               qsort(sorted_by_sha, nr_objects, sizeof(sorted_by_sha[0]),
+                     sha1_compare);
+
+       }
+       else
+               sorted_by_sha = list = last = NULL;
 
        unlink(index_name);
        f = sha1create("%s", index_name);