write_idx_file: need_large_offset() helper function
[git/git.git] / pack.h
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1#ifndef PACK_H
2#define PACK_H
3
1974632c 4#include "object.h"
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5
6/*
7 * Packed object header
8 */
9#define PACK_SIGNATURE 0x5041434b /* "PACK" */
29f049a0 10#define PACK_VERSION 2
d60fc1c8 11#define pack_version_ok(v) ((v) == htonl(2) || (v) == htonl(3))
a733cb60 12struct pack_header {
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13 uint32_t hdr_signature;
14 uint32_t hdr_version;
15 uint32_t hdr_entries;
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16};
17
df1b059d 18/*
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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.
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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
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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.
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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
ebcfb379 37struct pack_idx_option {
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38 unsigned flags;
39 /* flag bits */
40#define WRITE_IDX_VERIFY 01
41
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42 uint32_t version;
43 uint32_t off32_limit;
44};
45
46extern void reset_pack_idx_option(struct pack_idx_option *);
aa7e44bf 47
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48/*
49 * Packed object index header
50 */
51struct pack_idx_header {
52 uint32_t idx_signature;
53 uint32_t idx_version;
54};
55
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56/*
57 * Common part of object structure used for write_idx_file
58 */
59struct pack_idx_entry {
60 unsigned char sha1[20];
61 uint32_t crc32;
62 off_t offset;
63};
64
ebcfb379 65extern 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);
c41a4a94 66extern int check_pack_crc(struct packed_git *p, struct pack_window **w_curs, off_t offset, off_t len, unsigned int nr);
9b0aa728 67extern int verify_pack_index(struct packed_git *);
77d3ecee 68extern int verify_pack(struct packed_git *);
abeb40e5 69extern void fixup_pack_header_footer(int, unsigned char *, const char *, uint32_t, unsigned char *, off_t);
106764e6 70extern char *index_pack_lockfile(int fd);
f965c525 71extern int encode_in_pack_object_header(enum object_type, uintmax_t, unsigned char *);
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72
73#define PH_ERROR_EOF (-1)
74#define PH_ERROR_PACK_SIGNATURE (-2)
75#define PH_ERROR_PROTOCOL (-3)
76extern int read_pack_header(int fd, struct pack_header *);
a733cb60 77#endif