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                 if (ret == maxsize-1)
  21                         ret = -1;
  22                 /* Windows does not NUL-terminate if result fills buffer */
  23                 str[maxsize-1] = 0;
  24         }
  25         if (ret != -1)
  26                 return ret;
  27
  28         s = NULL;
  29         if (maxsize < 128)
  30                 maxsize = 128;
  31
  32         while (ret == -1) {
  33                 maxsize *= 4;
  34                 str = realloc(s, maxsize);
  35                 if (! str)
  36                         break;
  37                 s = str;
  38                 ret = vsnprintf(str, maxsize-SNPRINTF_SIZE_CORR, format, ap);
  39                 if (ret == maxsize-1)
  40                         ret = -1;
  41         }
  42         free(s);
  43         return ret;
  44 }
  45
  46 int git_snprintf(char *str, size_t maxsize, const char *format, ...)
  47 {
  48         va_list ap;
  49         int ret;
  50
  51         va_start(ap, format);
  52         ret = git_vsnprintf(str, maxsize, format, ap);
  53         va_end(ap);
  54
  55         return ret;
  56 }
  57