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 || defined(_MSC_VER)
  10 #define SNPRINTF_SIZE_CORR 1
  11 #else
  12 #define SNPRINTF_SIZE_CORR 0
  13 #endif
  14 #endif
  15
  16 #undef vsnprintf
  17
  18 #if defined(_MSC_VER)
  19 #define vsnprintf _vsnprintf
  20 #endif
  21
  22 int git_vsnprintf(char *str, size_t maxsize, const char *format, va_list ap)
  23 {
  24         char *s;
  25         int ret = -1;
  26
  27         if (maxsize > 0) {
  28                 ret = vsnprintf(str, maxsize-SNPRINTF_SIZE_CORR, format, ap);
  29                 if (ret == maxsize-1)
  30                         ret = -1;
  31                 /* Windows does not NUL-terminate if result fills buffer */
  32                 str[maxsize-1] = 0;
  33         }
  34         if (ret != -1)
  35                 return ret;
  36
  37         s = NULL;
  38         if (maxsize < 128)
  39                 maxsize = 128;
  40
  41         while (ret == -1) {
  42                 maxsize *= 4;
  43                 str = realloc(s, maxsize);
  44                 if (! str)
  45                         break;
  46                 s = str;
  47                 ret = vsnprintf(str, maxsize-SNPRINTF_SIZE_CORR, format, ap);
  48                 if (ret == maxsize-1)
  49                         ret = -1;
  50         }
  51         free(s);
  52         return ret;
  53 }
  54
  55 int git_snprintf(char *str, size_t maxsize, const char *format, ...)
  56 {
  57         va_list ap;
  58         int ret;
  59
  60         va_start(ap, format);
  61         ret = git_vsnprintf(str, maxsize, format, ap);
  62         va_end(ap);
  63
  64         return ret;
  65 }
  66