+ void *buf;
+
+ if (!usable_delta) {
+ buf = read_sha1_file(entry->idx.sha1, &type, &size);
+ if (!buf)
+ die("unable to read %s", sha1_to_hex(entry->idx.sha1));
+ /*
+ * make sure no cached delta data remains from a
+ * previous attempt before a pack split occurred.
+ */
+ free(entry->delta_data);
+ entry->delta_data = NULL;
+ entry->z_delta_size = 0;
+ } else if (entry->delta_data) {
+ size = entry->delta_size;
+ buf = entry->delta_data;
+ entry->delta_data = NULL;
+ type = (allow_ofs_delta && entry->delta->idx.offset) ?
+ OBJ_OFS_DELTA : OBJ_REF_DELTA;
+ } else {
+ buf = get_delta(entry);
+ size = entry->delta_size;
+ type = (allow_ofs_delta && entry->delta->idx.offset) ?
+ OBJ_OFS_DELTA : OBJ_REF_DELTA;
+ }
+
+ if (entry->z_delta_size)
+ datalen = entry->z_delta_size;
+ else
+ datalen = do_compress(&buf, size);
+
+ /*
+ * The object header is a byte of 'type' followed by zero or
+ * more bytes of length.
+ */
+ hdrlen = encode_in_pack_object_header(type, size, header);
+
+ if (type == OBJ_OFS_DELTA) {
+ /*
+ * Deltas with relative base contain an additional
+ * encoding of the relative offset for the delta
+ * base from this object's position in the pack.
+ */
+ off_t ofs = entry->idx.offset - entry->delta->idx.offset;
+ unsigned pos = sizeof(dheader) - 1;
+ dheader[pos] = ofs & 127;
+ while (ofs >>= 7)
+ dheader[--pos] = 128 | (--ofs & 127);
+ if (limit && hdrlen + sizeof(dheader) - pos + datalen + 20 >= limit) {
+ free(buf);
+ return 0;
+ }
+ sha1write(f, header, hdrlen);
+ sha1write(f, dheader + pos, sizeof(dheader) - pos);
+ hdrlen += sizeof(dheader) - pos;
+ } else if (type == OBJ_REF_DELTA) {
+ /*
+ * Deltas with a base reference contain
+ * an additional 20 bytes for the base sha1.
+ */
+ if (limit && hdrlen + 20 + datalen + 20 >= limit) {
+ free(buf);
+ return 0;
+ }
+ sha1write(f, header, hdrlen);
+ sha1write(f, entry->delta->idx.sha1, 20);
+ hdrlen += 20;
+ } else {
+ if (limit && hdrlen + datalen + 20 >= limit) {
+ free(buf);
+ return 0;
+ }
+ sha1write(f, header, hdrlen);
+ }
+ sha1write(f, buf, datalen);
+ free(buf);
+
+ return hdrlen + datalen;
+}
+
+/* Return 0 if we will bust the pack-size limit */
+static unsigned long write_reuse_object(struct sha1file *f, struct object_entry *entry,
+ unsigned long limit, int usable_delta)
+{
+ struct packed_git *p = entry->in_pack;
+ struct pack_window *w_curs = NULL;
+ struct revindex_entry *revidx;
+ off_t offset;
+ enum object_type type = entry->type;
+ unsigned long datalen;
+ unsigned char header[10], dheader[10];
+ unsigned hdrlen;
+
+ if (entry->delta)
+ type = (allow_ofs_delta && entry->delta->idx.offset) ?
+ OBJ_OFS_DELTA : OBJ_REF_DELTA;
+ hdrlen = encode_in_pack_object_header(type, entry->size, header);
+
+ offset = entry->in_pack_offset;
+ revidx = find_pack_revindex(p, offset);
+ datalen = revidx[1].offset - offset;
+ if (!pack_to_stdout && p->index_version > 1 &&
+ check_pack_crc(p, &w_curs, offset, datalen, revidx->nr)) {
+ error("bad packed object CRC for %s", sha1_to_hex(entry->idx.sha1));
+ unuse_pack(&w_curs);
+ return write_no_reuse_object(f, entry, limit, usable_delta);
+ }
+
+ offset += entry->in_pack_header_size;
+ datalen -= entry->in_pack_header_size;
+
+ if (!pack_to_stdout && p->index_version == 1 &&
+ check_pack_inflate(p, &w_curs, offset, datalen, entry->size)) {
+ error("corrupt packed object for %s", sha1_to_hex(entry->idx.sha1));
+ unuse_pack(&w_curs);
+ return write_no_reuse_object(f, entry, limit, usable_delta);
+ }
+
+ if (type == OBJ_OFS_DELTA) {
+ off_t ofs = entry->idx.offset - entry->delta->idx.offset;
+ unsigned pos = sizeof(dheader) - 1;
+ dheader[pos] = ofs & 127;
+ while (ofs >>= 7)
+ dheader[--pos] = 128 | (--ofs & 127);
+ if (limit && hdrlen + sizeof(dheader) - pos + datalen + 20 >= limit) {
+ unuse_pack(&w_curs);
+ return 0;
+ }
+ sha1write(f, header, hdrlen);
+ sha1write(f, dheader + pos, sizeof(dheader) - pos);
+ hdrlen += sizeof(dheader) - pos;
+ reused_delta++;
+ } else if (type == OBJ_REF_DELTA) {
+ if (limit && hdrlen + 20 + datalen + 20 >= limit) {
+ unuse_pack(&w_curs);
+ return 0;
+ }
+ sha1write(f, header, hdrlen);
+ sha1write(f, entry->delta->idx.sha1, 20);
+ hdrlen += 20;
+ reused_delta++;
+ } else {
+ if (limit && hdrlen + datalen + 20 >= limit) {
+ unuse_pack(&w_curs);
+ return 0;
+ }
+ sha1write(f, header, hdrlen);
+ }
+ copy_pack_data(f, p, &w_curs, offset, datalen);
+ unuse_pack(&w_curs);
+ reused++;
+ return hdrlen + datalen;
+}
+
+/* Return 0 if we will bust the pack-size limit */
+static unsigned long write_object(struct sha1file *f,
+ struct object_entry *entry,
+ off_t write_offset)
+{
+ unsigned long limit, len;