base64转码

来源：互联网发布：centos 配置hadoop 编辑：程序博客网时间：2024/06/18 06:35

Base64是网络上最常见的用于传输8Bit字节代码的编码方式之一，可用于在HTTP环境下传递较长的标识信息。最近在公司里面做了一个上传自定义图片的功能。就用到了base64转码。将二进制数据转换成base64数据，然后通过post方式提交给网站。
头文件：

#ifndef AFCBASE64_API_H#define AFCBASE64_API_H#define B64_EOLN                0xF0    // 换行/n#define B64_CR                  0xF1    // 回车/r#define B64_EOF                 0xF2    // 连字符-#define B64_WS                  0xE0    // 跳格或者空格（/t、space）#define B64_ERROR               0xFF    // 错误字符#define B64_NOT_BASE64(a)       (((a)|0x13) == 0xF3)//base64格式字符串使用的字符包括大小写字母各26个，加上10个数字，和加号“+”，斜杠“/”，一共64个字符static const CHAR* DATA_BIN2ASCII = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";static const BYTE DATA_ASCII2BIN[128] = {    0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xE0,0xF0,0xFF,0xFF,0xF1,0xFF,0xFF,    0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,    0xE0,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0x3E,0xFF,0xF2,0xFF,0x3F,    0x34,0x35,0x36,0x37,0x38,0x39,0x3A,0x3B,0x3C,0x3D,0xFF,0xFF,0xFF,0x00,0xFF,0xFF,    0xFF,0x00,0x01,0x02,0x03,0x04,0x05,0x06,0x07,0x08,0x09,0x0A,0x0B,0x0C,0x0D,0x0E,    0x0F,0x10,0x11,0x12,0x13,0x14,0x15,0x16,0x17,0x18,0x19,0xFF,0xFF,0xFF,0xFF,0xFF,    0xFF,0x1A,0x1B,0x1C,0x1D,0x1E,0x1F,0x20,0x21,0x22,0x23,0x24,0x25,0x26,0x27,0x28,    0x29,0x2A,0x2B,0x2C,0x2D,0x2E,0x2F,0x30,0x31,0x32,0x33,0xFF,0xFF,0xFF,0xFF,0xFF};class CImageToBase64{public:    CImageToBase64();    ~CImageToBase64();/*功能：将二进制数据转换成BASE64编码字符串参数说明：    inputBuffer：要编码的二进制数据    inputCount：数据长度    outputBuffer：存储转换后的BASE64编码字符串返回值：     -1：参数错误    >=0：有效编码长度（字符数）,不包括字符串结束符。备注：    等效于openssl中EVP_EncodeBlock函数*/int BASE64_Encode(const BYTE* inputBuffer, int inputCount, TCHAR* outputBuffer);/*功能：将BASE64编码字符串转换为二进制数据参数说明：    inputBuffer：BASE64编码字符串    inputCount：编码长度（字符数）,应该为4的倍数。    outputBuffer：存储转换后的二进制数据返回值：     -1：参数错误     -2：数据错误    >=0：转换后的字节数备注：    等效于openssl中EVP_DecodeBlock函数*/int BASE64_Decode( const TCHAR* inputBuffer, int inputCount, BYTE* outputBuffer);};#endif

cpp文件：

#include "StdAfx.h"#include "AFCBASE64_API.h"CImageToBase64::CImageToBase64(){}CImageToBase64::~CImageToBase64(){}int CImageToBase64::BASE64_Encode( const BYTE* inputBuffer, int inputCount, TCHAR* outputBuffer){    int i;    BYTE b0, b1, b2;    if((inputBuffer==NULL) || (inputCount<0))    {        return -1;//参数错误    }    if( outputBuffer != NULL )    {        for( i = inputCount; i > 0; i -= 3 )        {            if( i >= 3 )            {    // 将3字节数据转换成4个ASCII字符                b0 = *inputBuffer++;                b1 = *inputBuffer++;                b2 = *inputBuffer++;                *outputBuffer++ = DATA_BIN2ASCII[b0 >> 2];                *outputBuffer++ = DATA_BIN2ASCII[((b0 << 4) | (b1 >> 4)) & 0x3F];                *outputBuffer++ = DATA_BIN2ASCII[((b1 << 2) | (b2 >> 6)) & 0x3F];                *outputBuffer++ = DATA_BIN2ASCII[b2 & 0x3F];            }            else            {                b0 = *inputBuffer++;                if( i == 2 )b1 = *inputBuffer++; else b1 = 0;                *outputBuffer++ = DATA_BIN2ASCII[b0 >> 2];                *outputBuffer++ = DATA_BIN2ASCII[((b0 << 4) | (b1 >> 4)) & 0x3F];                *outputBuffer++ = (i == 1) ? TEXT('=') : DATA_BIN2ASCII[(b1 << 2) & 0x3F];                *outputBuffer++ = TEXT('=');            }        } // End for i        *outputBuffer++ = TEXT('/0');    // 添加字符串结束标记    }    return ((inputCount + 2)/3)*4;// 返回有效字符个数}int CImageToBase64::BASE64_Decode( const TCHAR* inputBuffer, int inputCount, BYTE* outputBuffer){    int i, j;    BYTE b[4];    TCHAR ch;    if( (inputBuffer == NULL) || (inputCount < 0) )    {        return -1;    // 参数错误    }    // 去除头部空白字符    while( inputCount > 0 )    {        ch = *inputBuffer;        if( (ch < 0) || (ch >= 0x80) )        {            return -2;    // 数据错误，不在ASCII字符编码范围内        }        else        {            if( DATA_ASCII2BIN[ch] == B64_WS )            {                inputBuffer++;                inputCount--;            }            else            {                break;            }        }    }    // 去除尾部的空白字符、回车换行字符、连字符    while( inputCount >= 4 )    {        ch = inputBuffer[inputCount - 1];        if( (ch < 0) || (ch >= 0x80) )        {            return -2;    // 数据错误，不在ASCII字符编码范围内        }        else        {            if( B64_NOT_BASE64(DATA_ASCII2BIN[ch]) )            {                inputCount--;            }            else            {                break;            }        }    }    // 字符串长度必须为4的倍数    if( (inputCount % 4) != 0 )    {        return -2;    // 数据错误    }    if( outputBuffer != NULL )    {        for( i = 0; i < inputCount; i += 4 )        {            for( j = 0; j < 4; j++ )            {                ch = *inputBuffer++;                if( (ch < 0) || (ch >= 0x80) )                {                    return -2;    // 数据错误，不在ASCII字符编码范围内                }                else                {                    if( ch == '=' )    // 发现BASE64编码中的填充字符                    {                        break;                    }                    else                    {                        b[j] = DATA_ASCII2BIN[ch];                        if( b[j] & 0x80 )                        {                            return -2;    // 数据错误，无效的Base64编码字符                        }                    }                                    }            } // End for j            if( j == 4 )            {                *outputBuffer++ = (b[0] << 2) | (b[1] >> 4);                *outputBuffer++ = (b[1] << 4) | (b[2] >> 2 );                *outputBuffer++ = (b[2] << 6) | b[3];            }            else if( j == 3 )            {    // 有1个填充字节                *outputBuffer++ = (b[0] << 2) | (b[1] >> 4);                *outputBuffer++ = (b[1] << 4) | (b[2] >> 2 );                return (i >> 2) * 3 + 2;            }            else if( j == 2 )            {    // 有2个填充字节                *outputBuffer++ = (b[0] << 2) | (b[1] >> 4);                return (i >> 2) * 3 + 1;            }            else            {                return -2;    // 数据错误，无效的Base64编码字符            }                    }    // End for i    }    return (inputCount >> 2) * 3;}

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