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 #define SNPRINTF_SIZE_CORR 0
  10 #endif
  11
  12 #undef vsnprintf
  13 int git_vsnprintf(char *str, size_t maxsize, const char *format, va_list ap)
  14 {
  15         char *s;
  16         int ret = -1;
  17
  18         if (maxsize > 0) {
  19                 ret = vsnprintf(str, maxsize-SNPRINTF_SIZE_CORR, format, ap);
  20                 /* Windows does not NUL-terminate if result fills buffer */
  21                 str[maxsize-1] = 0;
  22         }
  23         if (ret != -1)
  24                 return ret;
  25
  26         s = NULL;
  27         if (maxsize < 128)
  28                 maxsize = 128;
  29
  30         while (ret == -1) {
  31                 maxsize *= 4;
  32                 str = realloc(s, maxsize);
  33                 if (! str)
  34                         break;
  35                 s = str;
  36                 ret = vsnprintf(str, maxsize-SNPRINTF_SIZE_CORR, format, ap);
  37         }
  38         free(s);
  39         return ret;
  40 }
  41
  42 int git_snprintf(char *str, size_t maxsize, const char *format, ...)
  43 {
  44         va_list ap;
  45         int ret;
  46
  47         va_start(ap, format);
  48         ret = git_vsnprintf(str, maxsize, format, ap);
  49         va_end(ap);
  50
  51         return ret;
  52 }
  53