与Web交互可用的图片Base64编码

#ifndef ___BASE64_H___
#define ___BASE64_H___


#include <string>

using namespace std;

class CBase64
{
public:
    CBase64();
    ~CBase64();

    /*********************************************************
    * 函数说明：将输入数据进行base64编码
    * 参数说明：[in]pIn        需要进行编码的数据
                [in]uInLen  输入参数的字节数
                [out]strOut 输出的进行base64编码之后的字符串
    * 返回值  ：true处理成功,false失败
    **********************************************************/
    bool static Encode(const unsigned char *pIn, unsigned long uInLen, string& strOut);

    /*********************************************************
    * 函数说明：将输入数据进行base64编码
    * 参数说明：[in]pIn            需要进行编码的数据
                [in]uInLen        输入参数的字节数
                [out]pOut        输出的进行base64编码之后的字符串
                [out]uOutLen    输出的进行base64编码之后的字符串长度
    * 返回值  ：true处理成功,false失败
    **********************************************************/
    bool static Encode(const unsigned char *pIn, unsigned long uInLen, unsigned char *pOut, unsigned long *uOutLen);
    
    /*********************************************************
    * 函数说明：将输入数据进行base64解码
    * 参数说明：[in]strIn        需要进行解码的数据
                [out]pOut        输出解码之后的节数数据
                [out]uOutLen    输出的解码之后的字节数长度
    * 返回值  ：true处理成功,false失败
    **********************************************************/
    bool static Decode(const string& strIn, unsigned char *pOut, unsigned long *uOutLen) ;

    /*********************************************************
    * 函数说明：将输入数据进行base64解码
    * 参数说明：[in]strIn        需要进行解码的数据
                [out]pOut        输出解码之后的节数数据
                [out]uOutLen    输出的解码之后的字节数长度
    * 返回值  ：true处理成功,false失败
    **********************************************************/
    bool static Decode(const unsigned char *pIn, unsigned long uInLen, unsigned char *pOut, unsigned long *uOutLen) ;
};

#endif // ___BASE64_H___

#include "stdafx.h"

/*
 *
 *Base64?
 *
 *
 *
*/

#include "Base64.h"

static const char *g_pCodes =
    "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/=";

static const unsigned char g_pMap[256] =
{
    255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
    255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
    255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
    255, 255, 255, 255, 255, 255, 255,  62, 255, 255, 255,  63,
     52,  53,  54,  55,  56,  57,  58,  59,  60,  61, 255, 255,
    255, 254, 255, 255, 255,   0,   1,   2,   3,   4,   5,   6,
      7,   8,   9,  10,  11,  12,  13,  14,  15,  16,  17,  18,
     19,  20,  21,  22,  23,  24,  25, 255, 255, 255, 255, 255,
    255,  26,  27,  28,  29,  30,  31,  32,  33,  34,  35,  36,
     37,  38,  39,  40,  41,  42,  43,  44,  45,  46,  47,  48,
     49,  50,  51, 255, 255, 255, 255, 255, 255, 255, 255, 255,
    255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
    255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
    255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
    255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
    255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
    255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
    255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
    255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
    255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
    255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
    255, 255, 255, 255
};

CBase64::CBase64()
{
}

CBase64::~CBase64()
{
}

bool CBase64::Encode(const unsigned char *pIn, unsigned long uInLen, unsigned char *pOut, unsigned long *uOutLen)
{
    unsigned long i, len2, leven;
    unsigned char *p;

    if(pOut == NULL || *uOutLen == 0)
        return false;

    //ASSERT((pIn != NULL) && (uInLen != 0) && (pOut != NULL) && (uOutLen != NULL));

    len2 = ((uInLen + 2) / 3) << 2;
    if((*uOutLen) < (len2 + 1)) return false;

    p = pOut;
    leven = 3 * (uInLen / 3);
    for(i = 0; i < leven; i += 3)
    {
        *p++ = g_pCodes[pIn[0] >> 2];
        *p++ = g_pCodes[((pIn[0] & 3) << 4) + (pIn[1] >> 4)];
        *p++ = g_pCodes[((pIn[1] & 0xf) << 2) + (pIn[2] >> 6)];
        *p++ = g_pCodes[pIn[2] & 0x3f];
        pIn += 3;
    }

    if (i < uInLen)
    {
        unsigned char a = pIn[0];
        unsigned char b = ((i + 1) < uInLen) ? pIn[1] : 0;
        unsigned char c = 0;

        *p++ = g_pCodes[a >> 2];
        *p++ = g_pCodes[((a & 3) << 4) + (b >> 4)];
        *p++ = ((i + 1) < uInLen) ? g_pCodes[((b & 0xf) << 2) + (c >> 6)] : '=';
        *p++ = '=';
    }

    *p = 0; // Append NULL byte
    *uOutLen = p - pOut;
    return true;
}

bool CBase64::Encode(const unsigned char *pIn, unsigned long uInLen, string& strOut) 
{
    unsigned long i, len2, leven;
    strOut = "";

    //ASSERT((pIn != NULL) && (uInLen != 0) && (pOut != NULL) && (uOutLen != NULL));

    len2 = ((uInLen + 2) / 3) << 2;
    //if((*uOutLen) < (len2 + 1)) return false;

    //p = pOut;
    leven = 3 * (uInLen / 3);
    for(i = 0; i < leven; i += 3)
    {
        strOut += g_pCodes[pIn[0] >> 2];
        strOut += g_pCodes[((pIn[0] & 3) << 4) + (pIn[1] >> 4)];
        strOut += g_pCodes[((pIn[1] & 0xf) << 2) + (pIn[2] >> 6)];
        strOut += g_pCodes[pIn[2] & 0x3f];
        pIn += 3;
    }

    if (i < uInLen)
    {
        unsigned char a = pIn[0];
        unsigned char b = ((i + 1) < uInLen) ? pIn[1] : 0;
        unsigned char c = 0;

        strOut += g_pCodes[a >> 2];
        strOut += g_pCodes[((a & 3) << 4) + (b >> 4)];
        strOut += ((i + 1) < uInLen) ? g_pCodes[((b & 0xf) << 2) + (c >> 6)] : '=';
        strOut += '=';
    }

    //*p = 0; // Append NULL byte
    //*uOutLen = p - pOut;
    return true;
}

bool CBase64::Decode(const string& strIn, unsigned char *pOut, unsigned long *uOutLen) 
{
    unsigned long t, x, y, z;
    unsigned char c;
    unsigned long g = 3;

    //ASSERT((pIn != NULL) && (uInLen != 0) && (pOut != NULL) && (uOutLen != NULL));

    for(x = y = z = t = 0; x < strIn.length(); x++)
    {
        c = g_pMap[strIn[x]];
        if(c == 255) continue;
        if(c == 254) { c = 0; g--; }

        t = (t << 6) | c;

        if(++y == 4)
        {
            if((z + g) > *uOutLen) { return false; } // Buffer overflow
            pOut[z++] = (unsigned char)((t>>16)&255);
            if(g > 1) pOut[z++] = (unsigned char)((t>>8)&255);
            if(g > 2) pOut[z++] = (unsigned char)(t&255);
            y = t = 0;
        }
    }

    *uOutLen = z;
    return true;
}