int-to-str.c

/*
 * Copyright 2005, 2006, 2007
 * Nick Galbreath -- nickg [at] modp [dot] com
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are
 * met:
 *
 *   Redistributions of source code must retain the above copyright
 *   notice, this list of conditions and the following disclaimer.
 *
 *   Redistributions in binary form must reproduce the above copyright
 *   notice, this list of conditions and the following disclaimer in the
 *   documentation and/or other materials provided with the distribution.
 *
 *   Neither the name of the modp.com nor the names of its
 *   contributors may be used to endorse or promote products derived from
 *   this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 * This is the standard "new" BSD license:
 * http://www.opensource.org/licenses/bsd-license.php
 */

#include "int-to-str.h"

const char *decimal_digits = "0123456789";

ALWAYS_INLINE static void
strreverse(char* begin, char* end)
{
    char aux;
    while (end > begin)
        aux = *end, *end-- = *begin, *begin++ = aux;
}

ALWAYS_INLINE int32_t
int_to_string(int32_t value, char *str)
{
    char *wstr = str;
    // Take care of sign
    unsigned int uvalue = (value < 0) ? -value : value;
    // Conversion. Number is reversed.
    do
	*wstr++ = (char) decimal_digits[uvalue % 10];
    while (uvalue /= 10);
    if (value < 0)
	*wstr++ = '-';
    *wstr = '\0';
    // Reverse string
    strreverse(str, wstr - 1);

    return wstr - str;
}