File itoa.c

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/*
  Copyright (c) 2014 Arduino LLC.  All right reserved.

  This library is free software; you can redistribute it and/or
  modify it under the terms of the GNU Lesser General Public
  License as published by the Free Software Foundation; either
  version 2.1 of the License, or (at your option) any later version.

  This library is distributed in the hope that it will be useful,
  but WITHOUT ANY WARRANTY; without even the implied warranty of
  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
  See the GNU Lesser General Public License for more details.

  You should have received a copy of the GNU Lesser General Public
  License along with this library; if not, write to the Free Software
  Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
*/

#include <string.h>

#ifdef __cplusplus
extern "C" {
#endif

char *ltoa(long value, char *string, int radix) {
    char tmp[33];
    char *tp = tmp;
    long i;
    unsigned long v;
    int sign;
    char *sp;

    if (string == NULL) {
        return 0;
    }

    if (radix > 36 || radix <= 1) {
        return 0;
    }

    sign = (radix == 10 && value < 0);
    if (sign) {
        v = -value;
    } else {
        v = (unsigned long)value;
    }

    while (v || tp == tmp) {
        i = v % radix;
        v = v / radix;
        if (i < 10)
            *tp++ = i + '0';
        else
            *tp++ = i + 'a' - 10;
    }

    sp = string;

    if (sign)
        *sp++ = '-';
    while (tp > tmp)
        *sp++ = *--tp;
    *sp = 0;

    return string;
}

char *ultoa(unsigned long value, char *string, int radix) {
    char tmp[33];
    char *tp = tmp;
    long i;
    unsigned long v = value;
    char *sp;

    if (string == NULL) {
        return 0;
    }

    if (radix > 36 || radix <= 1) {
        return 0;
    }

    while (v || tp == tmp) {
        i = v % radix;
        v = v / radix;
        if (i < 10)
            *tp++ = i + '0';
        else
            *tp++ = i + 'a' - 10;
    }

    sp = string;

    while (tp > tmp)
        *sp++ = *--tp;
    *sp = 0;

    return string;
}

char *itoa(int value, char *string, int radix) {
    return ltoa(value, string, radix);
}

char *utoa(unsigned int value, char *string, int radix) {
    return ultoa(value, string, radix);
}

#ifdef __cplusplus
} // extern "C"
#endif