+ if ((st != Z_STREAM_END) || stream.total_out != delta_size)
+ die("delta data unpack failed");
+
+ /* The base entry _must_ be in the same pack */
+ if (!find_pack_entry_one(base_sha1, &base_ent, p))
+ die("failed to find delta-pack base object %s",
+ sha1_to_hex(base_sha1));
+ base = unpack_entry_gently(&base_ent, type, &base_size);
+ if (!base)
+ die("failed to read delta-pack base object %s",
+ sha1_to_hex(base_sha1));
+ result = patch_delta(base, base_size,
+ delta_data, delta_size,
+ &result_size);
+ if (!result)
+ die("failed to apply delta");
+ free(delta_data);
+ free(base);
+ *sizep = result_size;
+ return result;
+}
+
+static void *unpack_non_delta_entry(unsigned char *data,
+ unsigned long size,
+ unsigned long left)
+{
+ int st;
+ z_stream stream;
+ unsigned char *buffer;
+
+ buffer = xmalloc(size + 1);
+ buffer[size] = 0;
+ memset(&stream, 0, sizeof(stream));
+ stream.next_in = data;
+ stream.avail_in = left;
+ stream.next_out = buffer;
+ stream.avail_out = size;
+
+ inflateInit(&stream);
+ st = inflate(&stream, Z_FINISH);
+ inflateEnd(&stream);
+ if ((st != Z_STREAM_END) || stream.total_out != size) {
+ free(buffer);
+ return NULL;
+ }
+
+ return buffer;
+}
+
+static void *unpack_entry(struct pack_entry *entry,
+ char *type, unsigned long *sizep)
+{
+ struct packed_git *p = entry->p;
+ void *retval;
+
+ if (use_packed_git(p))
+ die("cannot map packed file");
+ retval = unpack_entry_gently(entry, type, sizep);
+ unuse_packed_git(p);
+ if (!retval)
+ die("corrupted pack file");
+ return retval;
+}
+
+/* The caller is responsible for use_packed_git()/unuse_packed_git() pair */
+void *unpack_entry_gently(struct pack_entry *entry,
+ char *type, unsigned long *sizep)
+{
+ struct packed_git *p = entry->p;
+ unsigned long offset, size, left;
+ unsigned char *pack;
+ enum object_type kind;
+ void *retval;
+
+ offset = unpack_object_header(p, entry->offset, &kind, &size);
+ pack = p->pack_base + offset;
+ left = p->pack_size - offset;
+ switch (kind) {
+ case OBJ_DELTA:
+ retval = unpack_delta_entry(pack, size, left, type, sizep, p);
+ return retval;
+ case OBJ_COMMIT:
+ strcpy(type, "commit");
+ break;
+ case OBJ_TREE:
+ strcpy(type, "tree");
+ break;
+ case OBJ_BLOB:
+ strcpy(type, "blob");
+ break;
+ case OBJ_TAG:
+ strcpy(type, "tag");
+ break;
+ default:
+ return NULL;
+ }
+ *sizep = size;
+ retval = unpack_non_delta_entry(pack, size, left);
+ return retval;
+}
+
+int num_packed_objects(const struct packed_git *p)
+{
+ /* See check_packed_git_idx() */
+ return (p->index_size - 20 - 20 - 4*256) / 24;
+}
+
+int nth_packed_object_sha1(const struct packed_git *p, int n,
+ unsigned char* sha1)
+{
+ void *index = p->index_base + 256;
+ if (n < 0 || num_packed_objects(p) <= n)
+ return -1;
+ memcpy(sha1, (index + 24 * n + 4), 20);
+ return 0;
+}
+
+int find_pack_entry_one(const unsigned char *sha1,
+ struct pack_entry *e, struct packed_git *p)
+{
+ unsigned int *level1_ofs = p->index_base;
+ int hi = ntohl(level1_ofs[*sha1]);
+ int lo = ((*sha1 == 0x0) ? 0 : ntohl(level1_ofs[*sha1 - 1]));
+ void *index = p->index_base + 256;
+
+ do {
+ int mi = (lo + hi) / 2;
+ int cmp = memcmp(index + 24 * mi + 4, sha1, 20);
+ if (!cmp) {
+ e->offset = ntohl(*((int*)(index + 24 * mi)));
+ memcpy(e->sha1, sha1, 20);
+ e->p = p;
+ return 1;
+ }
+ if (cmp > 0)
+ hi = mi;
+ else
+ lo = mi+1;
+ } while (lo < hi);
+ return 0;
+}
+
+static int find_pack_entry(const unsigned char *sha1, struct pack_entry *e)
+{
+ struct packed_git *p;
+ prepare_packed_git();
+
+ for (p = packed_git; p; p = p->next) {
+ if (find_pack_entry_one(sha1, e, p))
+ return 1;
+ }
+ return 0;
+}
+
+int sha1_object_info(const unsigned char *sha1, char *type, unsigned long *sizep)
+{
+ int status;
+ unsigned long mapsize, size;
+ void *map;
+ z_stream stream;
+ char hdr[128];
+
+ map = map_sha1_file_internal(sha1, &mapsize);
+ if (!map) {
+ struct pack_entry e;
+
+ if (!find_pack_entry(sha1, &e))
+ return error("unable to find %s", sha1_to_hex(sha1));
+ return packed_object_info(&e, type, sizep);
+ }
+ if (unpack_sha1_header(&stream, map, mapsize, hdr, sizeof(hdr)) < 0)
+ status = error("unable to unpack %s header",
+ sha1_to_hex(sha1));
+ if (parse_sha1_header(hdr, type, &size) < 0)
+ status = error("unable to parse %s header", sha1_to_hex(sha1));
+ else {
+ status = 0;
+ if (sizep)
+ *sizep = size;
+ }
+ inflateEnd(&stream);
+ munmap(map, mapsize);
+ return status;
+}
+
+static void *read_packed_sha1(const unsigned char *sha1, char *type, unsigned long *size)
+{
+ struct pack_entry e;
+
+ if (!find_pack_entry(sha1, &e)) {
+ error("cannot read sha1_file for %s", sha1_to_hex(sha1));
+ return NULL;
+ }
+ return unpack_entry(&e, type, size);