compat/snprintf.c

   1 #include "../git-compat-util.h"
   2
   3 /*
   4  * The size parameter specifies the available space, i.e. includes
   5  * the trailing NUL byte; but Windows's vsnprintf expects the
   6  * number of characters to write without the trailing NUL.
   7  */
   8 #ifndef SNPRINTF_SIZE_CORR
   9 #if defined(__MINGW32__) && defined(__GNUC__) && __GNUC__ < 4
  10 #define SNPRINTF_SIZE_CORR 1
  11 #else
  12 #define SNPRINTF_SIZE_CORR 0
  13 #endif
  14 #endif
  15
  16 #undef vsnprintf
  17 int git_vsnprintf(char *str, size_t maxsize, const char *format, va_list ap)
  18 {
  19         char *s;
  20         int ret = -1;
  21
  22         if (maxsize > 0) {
  23                 ret = vsnprintf(str, maxsize-SNPRINTF_SIZE_CORR, format, ap);
  24                 if (ret == maxsize-1)
  25                         ret = -1;
  26                 /* Windows does not NUL-terminate if result fills buffer */
  27                 str[maxsize-1] = 0;
  28         }
  29         if (ret != -1)
  30                 return ret;
  31
  32         s = NULL;
  33         if (maxsize < 128)
  34                 maxsize = 128;
  35
  36         while (ret == -1) {
  37                 maxsize *= 4;
  38                 str = realloc(s, maxsize);
  39                 if (! str)
  40                         break;
  41                 s = str;
  42                 ret = vsnprintf(str, maxsize-SNPRINTF_SIZE_CORR, format, ap);
  43                 if (ret == maxsize-1)
  44                         ret = -1;
  45         }
  46         free(s);
  47         return ret;
  48 }
  49
  50 int git_snprintf(char *str, size_t maxsize, const char *format, ...)
  51 {
  52         va_list ap;
  53         int ret;
  54
  55         va_start(ap, format);
  56         ret = git_vsnprintf(str, maxsize, format, ap);
  57         va_end(ap);
  58
  59         return ret;
  60 }
  61