ltoa.c

Rabbit 32Bit RTOS源代码

/*********************************************************************
*                   Copyright (c) 2011-2012,李士伟
*                     All rights reserved.
*文 件 名：ltoa.c
*描    述：长整数转化成ascii码
*当前版本：V1.00
*作    者：李士伟
*创建日期：2012.01.15
**********************************************************************/
#include <lib\ltoa.h>

/*********************************************************************
*函 数 名：ltoa
*描    述：长整数转化成二进制，八进制，十进制，十六进制的ascii码
*输入参数：num: 需转化的长整数
*          base: 转化进制
*输出参数：dst: 存储转化的ascii码 
*返 回 值：转化ascii码使用字节数(包含'\0')
*注    意：dst指向的内存是否足够存储转化的ascii码
**********************************************************************/
unsigned int ltoa(long num, int base, char *dst)
{
    unsigned int len;
    int flag = 0;
    const char hex[] = "0123456789abcdef";
    char buf[8 * sizeof(unsigned long) + 4];
    char *p = buf + 8 * sizeof(unsigned long) + 4;

    *--p = '\0';

    if (num < 0)
    {
        num = -num;
        flag = 1;
    }

    if (base == 10)
    {
        do
        {
            *--p = '0' + num % 10;
            num = num / 10;
        }
        while (num);
    }
    else if (base == 16)
    {
        do
        {
            *--p = hex[num % 16];
            num = num >> 4;
        }
        while (num);
        *--p = 'x';
        *--p = '0';
    }
    else if (base == 8)
    {
        do
        {
            *--p = (num & 0x07) + '0';
            num = num >> 3;
        }
        while (num);
        *--p = '0';
    }
    else if (base == 2)
    {
        do
        {
            *--p = (num & 0x01) + '0';
            num = num >> 1;
        }
        while (num);
        *--p = 'b';
        *--p = '0';
    }

    len = buf + 8 * sizeof(unsigned long) + 4 - p + flag;

    if (flag)
    {
        *dst++ = '-';
    }

    do
    {
        *dst++ = *p;
    }
    while (*p++ != '\0');

    return len;

}