utils.c

#include <stdint.h>

/**
 * C++ version 0.4 char* style "itoa":
 * Written by Lukás Chmela
 * Released under GPLv3.
 */
char* i32toa(int32_t value, char* result, int32_t base) {
  // check that the base if valid
  if (base < 2 || base > 36) { *result = '\0'; return result; }
  
  char *ptr = result, *ptr1 = result, tmp_char;
  int32_t tmp_value;
  
  do {
    tmp_value = value;
    value /= base;
    *ptr++ = "zyxwvutsrqponmlkjihgfedcba9876543210123456789abcdefghijklmnopqrstuvwxyz" [35 + (tmp_value - value * base)];
  } while ( value );
  
  // Apply negative sign
  if (tmp_value < 0) *ptr++ = '-';
  *ptr-- = '\0';
  while(ptr1 < ptr) {
    tmp_char = *ptr;
    *ptr-- = *ptr1;
    *ptr1++ = tmp_char;
  }
  return result;
}