base64　加密解密函数

王朝other·作者佚名 2006-01-09

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CString Base64Encode(LPCTSTR lpszSrc)

{

ASSERT(lpszSrc != NULL && AfxIsValidString(lpszSrc));

const char BASE64_ENCODE_TABLE[64] = {

65, 66, 67, 68, 69, 70, 71, 72, // 00 - 07

73, 74, 75, 76, 77, 78, 79, 80, // 08 - 15

81, 82, 83, 84, 85, 86, 87, 88, // 16 - 23

89, 90, 97, 98, 99, 100, 101, 102, // 24 - 31

103, 104, 105, 106, 107, 108, 109, 110, // 32 - 39

111, 112, 113, 114, 115, 116, 117, 118, // 40 - 47

119, 120, 121, 122, 48, 49, 50, 51, // 48 - 55

52, 53, 54, 55, 56, 57, 43, 47 };// 56 - 63

unsigned int iTest;

LPCTSTR pInBuffer=lpszSrc;

int nSize = (int)_tcslen(lpszSrc);

char* pOutBuffer=new char[nSize/3*4+5];

ZeroMemory(pOutBuffer,nSize/3*4+5);

for(UINT i=0;i<_tcslen(lpszSrc) / 3;i++)

{

iTest = (unsigned char) *pInBuffer++;

iTest = iTest << 8;

iTest = iTest | (unsigned char) *pInBuffer++;

iTest = iTest << 8;

iTest = iTest | (unsigned char) *pInBuffer++;

//以4 byte倒序写入输出缓冲

pOutBuffer[3] = BASE64_ENCODE_TABLE[iTest & 0x3F];

iTest = iTest >> 6;

pOutBuffer[2] = BASE64_ENCODE_TABLE[iTest & 0x3F];

iTest = iTest >> 6;

pOutBuffer[1] = BASE64_ENCODE_TABLE[iTest & 0x3F];

iTest = iTest >> 6;

pOutBuffer[0] = BASE64_ENCODE_TABLE[iTest];

pOutBuffer+=4;

}

//设置尾部

switch (_tcslen(lpszSrc) % 3)

{

case 0:

break;

case 1:

iTest = (unsigned char) *pInBuffer;

iTest = iTest << 4;

pOutBuffer[1] = BASE64_ENCODE_TABLE[iTest & 0x3F];

iTest = iTest >> 6;

pOutBuffer[0] = BASE64_ENCODE_TABLE[iTest];

pOutBuffer[2] = '='; //用'='也就是64码填充剩余部分

pOutBuffer[3] = '=';

break;

case 2:

iTest = (unsigned char) *pInBuffer++;

iTest = iTest << 8;

iTest = iTest | (unsigned char) *pInBuffer;

iTest = iTest << 2;

pOutBuffer[2] = BASE64_ENCODE_TABLE[iTest & 0x3F];

iTest = iTest >> 6;

pOutBuffer[1] = BASE64_ENCODE_TABLE[iTest & 0x3F];

iTest = iTest >> 6;

pOutBuffer[0] = BASE64_ENCODE_TABLE[iTest];

pOutBuffer[3] = '='; // Fill remaining byte.

break;

}

pOutBuffer-=nSize/3*4;

CString strEncode=pOutBuffer;

delete [] pOutBuffer;

pOutBuffer=NULL;

return strEncode;

}

CString Base64Decode(LPCTSTR lpszSrc)

{

ASSERT(lpszSrc != NULL && AfxIsValidString(lpszSrc));

const unsigned int BASE64_DECODE_TABLE[256] = {

255, 255, 255, 255, 255, 255, 255, 255, // 00 - 07

255, 255, 255, 255, 255, 255, 255, 255, // 08 - 15

255, 255, 255, 255, 255, 255, 255, 255, // 16 - 23

255, 255, 255, 255, 255, 255, 255, 255, // 24 - 31

255, 255, 255, 255, 255, 255, 255, 255, // 32 - 39

255, 255, 255, 62, 255, 255, 255, 63, // 40 - 47

52, 53, 54, 55, 56, 57, 58, 59, // 48 - 55

60, 61, 255, 255, 255, 255, 255, 255, // 56 - 63

255, 0, 1, 2, 3, 4, 5, 6, // 64 - 71

7, 8, 9, 10, 11, 12, 13, 14, // 72 - 79

15, 16, 17, 18, 19, 20, 21, 22, // 80 - 87

23, 24, 25, 255, 255, 255, 255, 255, // 88 - 95

255, 26, 27, 28, 29, 30, 31, 32, // 96 - 103

33, 34, 35, 36, 37, 38, 39, 40, // 104 - 111

41, 42, 43, 44, 45, 46, 47, 48, // 112 - 119

49, 50, 51, 255, 255, 255, 255, 255, // 120 - 127

255, 255, 255, 255, 255, 255, 255, 255,

255, 255, 255, 255, 255, 255, 255, 255 };

const int nSrcCount=(int)_tcslen(lpszSrc);

int nSize=nSrcCount/4*3;

if(lpszSrc[nSrcCount-1]=='=')

nSize--;

if(lpszSrc[nSrcCount-2]=='=')

nSize--;

char* pOutBuffer=new char[nSize+3];

ZeroMemory(pOutBuffer,nSize+3);

LPCTSTR pInBuffer=lpszSrc;

UINT iTest,iPack;

for(int i=0;i<nSize/3 ;i++)

{

for(int j=0;j<4;j++)

{

iTest = BASE64_DECODE_TABLE[*pInBuffer++]; // Read from InputBuffer.

//InPtr++;

if (iTest == 0xFF)

{

j--;

continue; //读到255非法字符

}

iPack = iPack << 6 ;

iPack = iPack | iTest ;

}

pOutBuffer[2] = iPack;

iPack = iPack >> 8;

pOutBuffer[1] = iPack;

iPack = iPack >> 8;

pOutBuffer[0] = iPack;

//准备写入后3位

pOutBuffer+= 3; iPack = 0;

}

switch(nSize%3)

{

case 1:

iTest = BASE64_DECODE_TABLE[*pInBuffer++]; // Read from InputBuffer.

if (iTest != 0xFF)

{

iPack = iPack << 6 ;

iPack = iPack | iTest ;

}

iTest = BASE64_DECODE_TABLE[*pInBuffer++]; // Read from InputBuffer.

if (iTest != 0xFF)

{

iPack = iPack << 6 ;

iPack = iPack | iTest ;

}

iPack = iPack >> 4;

pOutBuffer[0] = iPack;

pOutBuffer++;

break;

case 2:

iTest = BASE64_DECODE_TABLE[*pInBuffer++]; // Read from InputBuffer.

if (iTest != 0xFF)

{

iPack = iPack << 6 ;

iPack = iPack | iTest ;

}

iTest = BASE64_DECODE_TABLE[*pInBuffer++]; // Read from InputBuffer.

if (iTest != 0xFF)

{

iPack = iPack << 6 ;

iPack = iPack | iTest ;

}

iTest = BASE64_DECODE_TABLE[*pInBuffer++]; // Read from InputBuffer.

if (iTest != 0xFF)

{

iPack = iPack << 6 ;

iPack = iPack | iTest ;

}

iPack = iPack >> 2;

pOutBuffer[1] = iPack;

iPack = iPack >> 8;

pOutBuffer[0] = iPack;

pOutBuffer+=2;

break;

default:

break;

}

pOutBuffer-=nSize;

CString strDecode=pOutBuffer;

delete pOutBuffer;

return strDecode;

}

base64 加密解密函数

base64　加密解密函数