Merge branch 'jk/perf-no-dups'
[git/git.git] / compat / snprintf.c
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1#include "../git-compat-util.h"
2
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3/*
4 * The size parameter specifies the available space, i.e. includes
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5 * the trailing NUL byte; but Windows's vsnprintf uses the entire
6 * buffer and avoids the trailing NUL, should the buffer be exactly
7 * big enough for the result. Defining SNPRINTF_SIZE_CORR to 1 will
8 * therefore remove 1 byte from the reported buffer size, so we
9 * always have room for a trailing NUL byte.
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10 */
11#ifndef SNPRINTF_SIZE_CORR
dae26d30 12#if defined(WIN32) && (!defined(__GNUC__) || __GNUC__ < 4) && (!defined(_MSC_VER) || _MSC_VER < 1900)
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13#define SNPRINTF_SIZE_CORR 1
14#else
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15#define SNPRINTF_SIZE_CORR 0
16#endif
f90cf2b9 17#endif
f4626df5 18
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19#undef vsnprintf
20int git_vsnprintf(char *str, size_t maxsize, const char *format, va_list ap)
21{
a9bfbc5b 22 va_list cp;
c4582f93 23 char *s;
f4626df5 24 int ret = -1;
c4582f93 25
f4626df5 26 if (maxsize > 0) {
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27 va_copy(cp, ap);
28 ret = vsnprintf(str, maxsize-SNPRINTF_SIZE_CORR, format, cp);
29 va_end(cp);
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30 if (ret == maxsize-1)
31 ret = -1;
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32 /* Windows does not NUL-terminate if result fills buffer */
33 str[maxsize-1] = 0;
34 }
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35 if (ret != -1)
36 return ret;
37
38 s = NULL;
39 if (maxsize < 128)
40 maxsize = 128;
41
42 while (ret == -1) {
43 maxsize *= 4;
44 str = realloc(s, maxsize);
45 if (! str)
46 break;
47 s = str;
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48 va_copy(cp, ap);
49 ret = vsnprintf(str, maxsize-SNPRINTF_SIZE_CORR, format, cp);
50 va_end(cp);
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51 if (ret == maxsize-1)
52 ret = -1;
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53 }
54 free(s);
55 return ret;
56}
57
58int git_snprintf(char *str, size_t maxsize, const char *format, ...)
59{
60 va_list ap;
61 int ret;
62
63 va_start(ap, format);
64 ret = git_vsnprintf(str, maxsize, format, ap);
65 va_end(ap);
66
67 return ret;
68}
69