base64编码和解码

来源：互联网发布：淘宝网日本忍者服装编辑：程序博客网时间：2024/05/17 21:51
写了个base64编解码程序，由于是自己写着玩的，所以写的比较随意，功能已经测试过了，都很正常。
#include <stdio.h>#include <stdlib.h>#include <string.h>#include <assert.h>static int ZJF_Mail_int2char_FUN(int a){    if(a <= 25)    {        return 'A'+(a-0);    }    else if((a > 25)&&(a <= 51))    {        return 'a'+(a-26);    }    else if((a > 51)&&(a < 61))    {        return '0'+(a-52);    }    else if(a == '=')    {        return a;    }    else if(a == 62)    {        return '+';    }    else if(a == 63)    {        return '/';    }    return 0;}static int ZJF_Mail_char2int_FUN(char ch){    if((ch >= 'A')&&(ch <= 'Z'))    {        return ch-'A';    }    else if((ch >= 'a')&&(ch <= 'z'))    {        return ch-'a'+26;    }    else if((ch >= '0')&&(ch <= '9'))    {        return ch - '0'+52;    }    else if(ch == '=')    {        return ch;    }    else if(ch == '+')    {        return 62;    }    else if(ch == '/')    {        return 63;    }    return 0;}static int ZJF_Mail_LittleToBig_FUN(char *str1,int len){    int i    = 0;    int temp = 0;    for(i = 0; i < len; i++)    {        temp |= ((int)str1[i] << (len-i-1)*8);            }    //printf("%#x \n",temp);     return temp;}static int ZJF_Mail_BigToLittle_FUN(char *str1,int len){    int i           = 0;    char temp[1024] = { 0 };    memcpy(temp,str1,len);    for(i = 0; i < len; i++)    {        str1[i] = temp[len-i-1];       }       return 0;}/*编码*/static int ZJF_Mail_Base64Encod_FUN(char * data,int len){    assert(data);    assert(len>0);    int i,j,k;    char strtemp[4] = { 0 };  /*每次拷贝三个字节出来，存储*/    int temp = 0;    char * pbuffer = (char * )malloc(len/3*4+4);    for(i = 0,j = 0; i < len/3; i++)    {                    memcpy(strtemp,data+3*i,3);            temp = ZJF_Mail_LittleToBig_FUN(strtemp,3);        pbuffer[j++] = (temp>>18)&0x3f;           pbuffer[j++] = (temp>>12)&0x3f;          pbuffer[j++] = (temp>>6)&0x3f;           pbuffer[j++] = (temp>>0)&0x3f;           if(j == 75)        {            //pbuffer[j++] = '\n';        }    }    if(len%3 == 1)    {        memcpy(strtemp,data+3*i,1);        temp = (int)strtemp[0];             pbuffer[j++] = temp>>2;        pbuffer[j++] = (temp&0x03)<<4;        pbuffer[j++] = '=';        pbuffer[j++] = '=';    }    else if(len%3 == 2)    {        memcpy(strtemp,data+3*i,2);        temp = ZJF_Mail_LittleToBig_FUN(strtemp,2);        pbuffer[j++] = temp>>10;        pbuffer[j++] = (temp>>4)&0x3f;        pbuffer[j++] = (temp<<2)&0x3f;        pbuffer[j++] = '=';    }    pbuffer[j++] = '\0';    printf("编码数据:");    for(i = 0;i < j-1;i++)    {        printf("%c",ZJF_Mail_int2char_FUN(pbuffer[i]));    }    printf("\n");    if(pbuffer != NULL)    {        free(pbuffer);        pbuffer = NULL;    }    return 0;}/*解码*/static int ZJF_Mail_Base64Decod_FUN(char * data,int len){    assert(data);    assert(len>0);    int i    = 0;    int j    = 0;    int temp = 0;    int a = 0;    char buf[1024] = { 0 };    char * pbuffer = (char * )malloc(len);    for(i = 0;i < len;i++)    {        pbuffer[i] = ZJF_Mail_char2int_FUN(data[i]);    }    for(i = 0;i < len/4;i++)    {        temp = 0;        for(j = 0;j < 4;j++)        {               a = 0;            a = pbuffer[4*i+j];            /*先把等号处理掉*/            if(a == '=')            {                a = 0;            }            temp |= a<<((3-j)*6);        }        memcpy(buf+i*3,(char*)&temp,3);        ZJF_Mail_BigToLittle_FUN(buf+3*i,3);    }    printf("解码后数据:%s \n",buf);    if(NULL != pbuffer)    {        free(pbuffer);        pbuffer = NULL;    }    return 0;}int main(){    int type = 0;    int len  = 0;    char buf[1024] = { 0 };    char ch;    printf("1: 编码\n2: 解码\n\n");INPUT:      printf("请输入:");    scanf("%s",buf);    fflush(stdin);    type = atoi(buf);    if((type != 1)&&(type != 2))    {        printf("输入 %d 错误 ! 请输入 1 或者 2 \n请输入:",type);                goto INPUT;    }    printf("%s初始化成功,请输入数据:",type == 1 ? "编码器":"解码器");    scanf("%s",buf);    len = strlen(buf);    switch(type)    {        case 1: /*编码*/        {            ZJF_Mail_Base64Encod_FUN(buf,len);        }        break;        case 2: /*解码*/        {            ZJF_Mail_Base64Decod_FUN(buf,len);        }        break;        default:            printf("input %d is err ! please input 1 or 2 \n",type);    }    return 0;}
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