lib/vsnprintf.c

   1 /*
   2  * vsnprintf()
   3  *
   4  * Poor substitute for a real vsnprintf() function for systems
   5  * that don't have them...
   6  */
   7
   8 #include "compiler.h"
   9
  10 #include <stdio.h>
  11 #include <stdlib.h>
  12 #include <stdarg.h>
  13 #include <string.h>
  14
  15 #include "nasmlib.h"
  16
  17 #define BUFFER_SIZE     65536   /* Bigger than any string we might print... */
  18
  19 static char snprintf_buffer[BUFFER_SIZE];
  20
  21 int vsnprintf(char *str, size_t size, const char *format, va_list ap)
  22 {
  23     int rv, bytes;
  24
  25     if (size > BUFFER_SIZE) {
  26         nasm_malloc_error(ERR_PANIC|ERR_NOFILE,
  27                           "snprintf: size (%d) > BUFFER_SIZE (%d)",
  28                           size, BUFFER_SIZE);
  29         size = BUFFER_SIZE;
  30     }
  31
  32     rv = vsprintf(snprintf_buffer, format, ap);
  33     if (rv >= BUFFER_SIZE) {
  34         nasm_malloc_error(ERR_PANIC|ERR_NOFILE,
  35                           "snprintf buffer overflow");
  36     }
  37
  38     if (size > 0) {
  39         if ((size_t)rv < size-1)
  40             bytes = rv;
  41         else
  42             bytes = size-1;
  43
  44         memcpy(str, snprintf_buffer, bytes);
  45         str[bytes] = '\0';
  46     }
  47
  48     return rv;
  49 }