pack-objects: no delta possible with only one object in the list
[git/git.git] / csum-file.c
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CommitLineData
1/*
2 * csum-file.c
3 *
4 * Copyright (C) 2005 Linus Torvalds
5 *
6 * Simple file write infrastructure for writing SHA1-summed
7 * files. Useful when you write a file that you want to be
8 * able to verify hasn't been messed with afterwards.
9 */
10#include "cache.h"
11#include "csum-file.h"
12
13static void sha1flush(struct sha1file *f, unsigned int count)
14{
15 void *buf = f->buffer;
16
17 for (;;) {
18 int ret = xwrite(f->fd, buf, count);
19 if (ret > 0) {
20 buf = (char *) buf + ret;
21 count -= ret;
22 if (count)
23 continue;
24 return;
25 }
26 if (!ret)
27 die("sha1 file '%s' write error. Out of diskspace", f->name);
28 die("sha1 file '%s' write error (%s)", f->name, strerror(errno));
29 }
30}
31
32int sha1close(struct sha1file *f, unsigned char *result, int final)
33{
34 unsigned offset = f->offset;
35 if (offset) {
36 SHA1_Update(&f->ctx, f->buffer, offset);
37 sha1flush(f, offset);
38 f->offset = 0;
39 }
40 if (!final)
41 return 0; /* only want to flush (no checksum write, no close) */
42 SHA1_Final(f->buffer, &f->ctx);
43 if (result)
44 hashcpy(result, f->buffer);
45 sha1flush(f, 20);
46 if (close(f->fd))
47 die("%s: sha1 file error on close (%s)", f->name, strerror(errno));
48 free(f);
49 return 0;
50}
51
52int sha1write(struct sha1file *f, void *buf, unsigned int count)
53{
54 if (f->do_crc)
55 f->crc32 = crc32(f->crc32, buf, count);
56 while (count) {
57 unsigned offset = f->offset;
58 unsigned left = sizeof(f->buffer) - offset;
59 unsigned nr = count > left ? left : count;
60
61 memcpy(f->buffer + offset, buf, nr);
62 count -= nr;
63 offset += nr;
64 buf = (char *) buf + nr;
65 left -= nr;
66 if (!left) {
67 SHA1_Update(&f->ctx, f->buffer, offset);
68 sha1flush(f, offset);
69 offset = 0;
70 }
71 f->offset = offset;
72 }
73 return 0;
74}
75
76struct sha1file *sha1fd(int fd, const char *name)
77{
78 struct sha1file *f;
79 unsigned len;
80
81 f = xmalloc(sizeof(*f));
82
83 len = strlen(name);
84 if (len >= PATH_MAX)
85 die("you wascally wabbit, you");
86 f->namelen = len;
87 memcpy(f->name, name, len+1);
88
89 f->fd = fd;
90 f->error = 0;
91 f->offset = 0;
92 f->do_crc = 0;
93 SHA1_Init(&f->ctx);
94 return f;
95}
96
97void crc32_begin(struct sha1file *f)
98{
99 f->crc32 = crc32(0, Z_NULL, 0);
100 f->do_crc = 1;
101}
102
103uint32_t crc32_end(struct sha1file *f)
104{
105 f->do_crc = 0;
106 return f->crc32;
107}