Andrew's git - gitweb.git/blob

   1#ifndef PACK_H
   2#define PACK_H
   3
   4#include "object.h"
   5
   6/*
   7 * Packed object header
   8 */
   9#define PACK_SIGNATURE 0x5041434b       /* "PACK" */
  10#define PACK_VERSION 2
  11#define pack_version_ok(v) ((v) == htonl(2) || (v) == htonl(3))
  12struct pack_header {
  13        uint32_t hdr_signature;
  14        uint32_t hdr_version;
  15        uint32_t hdr_entries;
  16};
  17
  18/*
  19 * Packed object index header
  20 *
  21 * struct pack_idx_header {
  22 *      uint32_t idx_signature;
  23 *      uint32_t idx_version;
  24 * };
  25 *
  26 * Note: this header isn't active yet.  In future versions of git
  27 * we may change the index file format.  At that time we would start
  28 * the first four bytes of the new index format with this signature,
  29 * as all older git binaries would find this value illegal and abort
  30 * reading the file.
  31 *
  32 * This is the case because the number of objects in a packfile
  33 * cannot exceed 1,431,660,000 as every object would need at least
  34 * 3 bytes of data and the overall packfile cannot exceed 4 GiB due
  35 * to the 32 bit offsets used by the index.  Clearly the signature
  36 * exceeds this maximum.
  37 *
  38 * Very old git binaries will also compare the first 4 bytes to the
  39 * next 4 bytes in the index and abort with a "non-monotonic index"
  40 * error if the second 4 byte word is smaller than the first 4
  41 * byte word.  This would be true in the proposed future index
  42 * format as idx_signature would be greater than idx_version.
  43 */
  44#define PACK_IDX_SIGNATURE 0xff744f63   /* "\377tOc" */
  45
  46extern int verify_pack(struct packed_git *, int);
  47
  48#define PH_ERROR_EOF            (-1)
  49#define PH_ERROR_PACK_SIGNATURE (-2)
  50#define PH_ERROR_PROTOCOL       (-3)
  51extern int read_pack_header(int fd, struct pack_header *);
  52#endif