xref: /third_party/mesa3d/src/util/u_printf.c (revision bf215546)
1//
2// Copyright 2020 Serge Martin
3//
4// Permission is hereby granted, free of charge, to any person obtaining a
5// copy of this software and associated documentation files (the "Software"),
6// to deal in the Software without restriction, including without limitation
7// the rights to use, copy, modify, merge, publish, distribute, sublicense,
8// and/or sell copies of the Software, and to permit persons to whom the
9// Software is furnished to do so, subject to the following conditions:
10//
11// The above copyright notice and this permission notice shall be included in
12// all copies or substantial portions of the Software.
13//
14// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
15// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
16// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
17// THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR
18// OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
19// ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
20// OTHER DEALINGS IN THE SOFTWARE.
21//
22// Extract from Serge's printf clover code by airlied.
23
24#include <assert.h>
25#include <stdarg.h>
26#include <string.h>
27
28#include "macros.h"
29#include "u_printf.h"
30
31/* Some versions of MinGW are missing _vscprintf's declaration, although they
32 * still provide the symbol in the import library. */
33#ifdef __MINGW32__
34_CRTIMP int _vscprintf(const char *format, va_list argptr);
35#endif
36
37#ifndef va_copy
38#ifdef __va_copy
39#define va_copy(dest, src) __va_copy((dest), (src))
40#else
41#define va_copy(dest, src) (dest) = (src)
42#endif
43#endif
44
45size_t util_printf_next_spec_pos(const char *str, size_t pos)
46{
47   if (str == NULL)
48      return -1;
49
50   const char *str_found = str + pos;
51   do {
52      str_found = strchr(str_found, '%');
53      if (str_found == NULL)
54         return -1;
55
56      ++str_found;
57      if (*str_found == '%') {
58         ++str_found;
59         continue;
60      }
61
62      char *spec_pos = strpbrk(str_found, "cdieEfFgGaAosuxXp%");
63      if (spec_pos == NULL) {
64         return -1;
65      } else if (*spec_pos == '%') {
66         str_found = spec_pos;
67      } else {
68         return spec_pos - str;
69      }
70   } while (1);
71}
72
73size_t u_printf_length(const char *fmt, va_list untouched_args)
74{
75   int size;
76   char junk;
77
78   /* Make a copy of the va_list so the original caller can still use it */
79   va_list args;
80   va_copy(args, untouched_args);
81
82#ifdef _WIN32
83   /* We need to use _vcsprintf to calculate the size as vsnprintf returns -1
84    * if the number of characters to write is greater than count.
85    */
86   size = _vscprintf(fmt, args);
87   (void)junk;
88#else
89   size = vsnprintf(&junk, 1, fmt, args);
90#endif
91   assert(size >= 0);
92
93   va_end(args);
94
95   return size;
96}
97