os-k/kaleid/common/itoa.c

//----------------------------------------------------------------------------//
//                           GNU GPL OS/K                                     //
//                                                                            //
//  Authors:    spectral`                                                     //
//              NeoX                                                          //
//                                                                            //
//  Desc:       Conversion utilities - itoa family                            //
//----------------------------------------------------------------------------//

#include <kaleid.h>

//
// Digits table for bases <=36
//
static const char digits[] =
        "0123456789abcdefghijklmnopqrstuvwxyz";
//
// Integer to string in any base between 2 and 36 (included)
//
#if defined(_NEED_ITOA)
char *itoa(int i, char *str, int base)
#elif defined(_NEED_LTOA)
char *ltoa(long i, char *str, int base)
#elif defined(_NEED_UTOA)
char *utoa(uint i, char *str, int base)
#elif defined(_NEED_ULTOA)
char *ultoa(ulong i, char *str, int base)
#else
#error "What am I supposed to declare?"
#endif
{
#if defined(_NEED_ITOA) || defined(_NEED_LTOA)
    int neg = 0;
#endif

    char *orig = str;

    //
    // Only handle base 2 -> 36
    //
    if (base < 2 || base > 36)
        return NULL;

#if defined(_NEED_ITOA) || defined(_NEED_LTOA)
    //
    // Deal with negatives
    //
    if (i < 0) {
        neg = 1;
        i = -i;
    }
#endif

    //
    // Deal with zero separately
    //
    if (i == 0) {
        *str++ = '0';
    }

    //
    // Compute digits... in reverse order
    //
    while (i > 0) {
        *str++ = digits[i % base];
        i /= base;
    }

#if defined(_NEED_ITOA) || defined(_NEED_LTOA)
    if (neg) *str++ = '-';
#endif

    *str = '\0';

    //
    // Reverse the string
    //
    return strrev2(orig);
}