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 * The first four bytes of index formats later than version 1 should 20 * start with this signature, as all older git binaries would find this 21 * value illegal and abort reading the file. 22 * 23 * This is the case because the number of objects in a packfile 24 * cannot exceed 1,431,660,000 as every object would need at least 25 * 3 bytes of data and the overall packfile cannot exceed 4 GiB with 26 * version 1 of the index file due to the offsets limited to 32 bits. 27 * Clearly the signature exceeds this maximum. 28 * 29 * Very old git binaries will also compare the first 4 bytes to the 30 * next 4 bytes in the index and abort with a "non-monotonic index" 31 * error if the second 4 byte word is smaller than the first 4 32 * byte word. This would be true in the proposed future index 33 * format as idx_signature would be greater than idx_version. 34 */ 35#define PACK_IDX_SIGNATURE 0xff744f63 /* "\377tOc" */ 36 37struct pack_idx_option { 38 uint32_t version; 39 uint32_t off32_limit; 40}; 41 42extern void reset_pack_idx_option(struct pack_idx_option *); 43 44/* 45 * Packed object index header 46 */ 47struct pack_idx_header { 48 uint32_t idx_signature; 49 uint32_t idx_version; 50}; 51 52/* 53 * Common part of object structure used for write_idx_file 54 */ 55struct pack_idx_entry { 56 unsigned char sha1[20]; 57 uint32_t crc32; 58 off_t offset; 59}; 60 61extern const char *write_idx_file(const char *index_name, struct pack_idx_entry **objects, int nr_objects, const struct pack_idx_option *, unsigned char *sha1); 62extern int check_pack_crc(struct packed_git *p, struct pack_window **w_curs, off_t offset, off_t len, unsigned int nr); 63extern int verify_pack_index(struct packed_git *); 64extern int verify_pack(struct packed_git *); 65extern void fixup_pack_header_footer(int, unsigned char *, const char *, uint32_t, unsigned char *, off_t); 66extern char *index_pack_lockfile(int fd); 67extern int encode_in_pack_object_header(enum object_type, uintmax_t, unsigned char *); 68 69#define PH_ERROR_EOF (-1) 70#define PH_ERROR_PACK_SIGNATURE (-2) 71#define PH_ERROR_PROTOCOL (-3) 72extern int read_pack_header(int fd, struct pack_header *); 73#endif