+ char hdr[8192];
+
+ ret = unpack_sha1_header(&stream, map, mapsize, hdr, sizeof(hdr));
+ if (ret < Z_OK || parse_sha1_header(hdr, type, size) < 0)
+ return NULL;
+
+ return unpack_sha1_rest(&stream, hdr, *size);
+}
+
+/* forward declaration for a mutually recursive function */
+static int packed_object_info(struct pack_entry *entry,
+ char *type, unsigned long *sizep);
+
+static int packed_delta_info(unsigned char *base_sha1,
+ unsigned long delta_size,
+ unsigned long left,
+ char *type,
+ unsigned long *sizep,
+ struct packed_git *p)
+{
+ struct pack_entry base_ent;
+
+ if (left < 20)
+ die("truncated pack file");
+
+ /* 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));
+
+ /* We choose to only get the type of the base object and
+ * ignore potentially corrupt pack file that expects the delta
+ * based on a base with a wrong size. This saves tons of
+ * inflate() calls.
+ */
+
+ if (packed_object_info(&base_ent, type, NULL))
+ die("cannot get info for delta-pack base");
+
+ if (sizep) {
+ const unsigned char *data;
+ unsigned char delta_head[64];
+ unsigned long result_size;
+ z_stream stream;
+ int st;
+
+ memset(&stream, 0, sizeof(stream));
+
+ data = stream.next_in = base_sha1 + 20;
+ stream.avail_in = left - 20;
+ stream.next_out = delta_head;
+ stream.avail_out = sizeof(delta_head);
+
+ inflateInit(&stream);
+ st = inflate(&stream, Z_FINISH);
+ inflateEnd(&stream);
+ if ((st != Z_STREAM_END) &&
+ stream.total_out != sizeof(delta_head))
+ die("delta data unpack-initial failed");
+
+ /* Examine the initial part of the delta to figure out
+ * the result size.
+ */
+ data = delta_head;
+ get_delta_hdr_size(&data); /* ignore base size */
+
+ /* Read the result size */
+ result_size = get_delta_hdr_size(&data);
+ *sizep = result_size;
+ }
+ return 0;
+}
+
+static unsigned long unpack_object_header(struct packed_git *p, unsigned long offset,
+ enum object_type *type, unsigned long *sizep)
+{
+ unsigned shift;
+ unsigned char *pack, c;
+ unsigned long size;
+
+ if (offset >= p->pack_size)
+ die("object offset outside of pack file");
+
+ pack = p->pack_base + offset;
+ c = *pack++;
+ offset++;
+ *type = (c >> 4) & 7;
+ size = c & 15;
+ shift = 4;
+ while (c & 0x80) {
+ if (offset >= p->pack_size)
+ die("object offset outside of pack file");
+ c = *pack++;
+ offset++;
+ size += (c & 0x7f) << shift;
+ shift += 7;
+ }
+ *sizep = size;
+ return offset;
+}
+
+void packed_object_info_detail(struct pack_entry *e,
+ char *type,
+ unsigned long *size,
+ unsigned long *store_size,
+ int *delta_chain_length,
+ unsigned char *base_sha1)
+{
+ struct packed_git *p = e->p;
+ unsigned long offset, left;
+ unsigned char *pack;
+ enum object_type kind;
+
+ offset = unpack_object_header(p, e->offset, &kind, size);
+ pack = p->pack_base + offset;
+ left = p->pack_size - offset;
+ if (kind != OBJ_DELTA)
+ *delta_chain_length = 0;
+ else {
+ int chain_length = 0;
+ memcpy(base_sha1, pack, 20);
+ do {
+ struct pack_entry base_ent;
+ unsigned long junk;
+
+ find_pack_entry_one(pack, &base_ent, p);
+ offset = unpack_object_header(p, base_ent.offset,
+ &kind, &junk);
+ pack = p->pack_base + offset;
+ chain_length++;
+ } while (kind == OBJ_DELTA);
+ *delta_chain_length = chain_length;
+ }
+ switch (kind) {
+ 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:
+ die("corrupted pack file");
+ }
+ *store_size = 0; /* notyet */
+}
+
+static int packed_object_info(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;
+ int retval;
+
+ if (use_packed_git(p))
+ die("cannot map packed file");
+
+ 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 = packed_delta_info(pack, size, left, type, sizep, p);
+ unuse_packed_git(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:
+ die("corrupted pack file");
+ }
+ if (sizep)
+ *sizep = size;
+ unuse_packed_git(p);
+ return 0;
+}
+
+/* forward declaration for a mutually recursive function */
+static void *unpack_entry(struct pack_entry *, char *, unsigned long *);
+
+static void *unpack_delta_entry(unsigned char *base_sha1,
+ unsigned long delta_size,
+ unsigned long left,
+ char *type,
+ unsigned long *sizep,
+ struct packed_git *p)
+{
+ struct pack_entry base_ent;
+ void *data, *delta_data, *result, *base;
+ unsigned long data_size, result_size, base_size;
+ z_stream stream;
+ int st;
+
+ if (left < 20)
+ die("truncated pack file");
+ data = base_sha1 + 20;
+ data_size = left - 20;
+ delta_data = xmalloc(delta_size);