coder.cpp

移动使用的加密程序

/*
*
*	编码类的实现
*	作者		Tintin  [e-mail]
*	日期		2001-4-15
*	最后修改	2001-4-19
*
*/

#include "Coder.h"

//编码时候的每行的长度
unsigned int CCoder::m_LineWidth = 76;
//------------------------------------------------------------------------------

//Base64解码表
const char CCoder::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
	
	//Base64编码表
const unsigned int CCoder::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,
	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 };
//------------------------------------------------------------------------------
		
//Quoted编码表
const unsigned char CCoder::QUOTED_ENCODE_TABLE[256] = {
	255, 255, 255, 255, 255, 255, 255, 255, // 00 -  07
	255, 255,  10, 255, 255,  13, 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,  33,  34,  35,  36,  37,  38,  39,
	 40,  41,  42,  43,  44,  45,  46,  47,
	 48,  49,  50,  51,  52,  53,  54,  55,
	 56,  57,  58,  59,  60, 255,  62,  63,
	 64,  65,  66,  67,  68,  69,  70,  71,
	 72,  73,  74,  75,  76,  77,  78,  79,
	 80,  81,  82,  83,  84,  85,  86,  87,
	 88,  89,  90,  91,  92,  93,  94,  95,
	 96,  97,  98,  99, 100, 101, 102, 103,
	104, 105, 106, 107, 108, 109, 110, 111,
	112, 113, 114, 115, 116, 117, 118, 119,
	120, 121, 122, 123, 124, 125, 126, 127,
	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 };
//------------------------------------------------------------------------------
			
//获取Base64编码长度
int CCoder::Base64EncodeSize(int iSize)
{
	int nSize, nCR;
	nSize = (iSize + 2) / 3 * 4 ;
	nCR = nSize / m_LineWidth; //计算回车数量
	nSize+= nCR * 2;
	return nSize;
}
	
//------------------------------------------------------------------------------
	
//获取Base64解码长度
int CCoder::Base64DecodeSize(int iSize)
{
	return (iSize + 3) / 4 * 3;
}


//------------------------------------------------------------------------------

//Base64编码
int CCoder::base64_encode(char *pSrc, unsigned int nSize, char *pDest)
{
	if ((pSrc == NULL) || (nSize <= 0)) return 0;
		
	unsigned int iB, iInMax3, Len;
	char *pInPtr, *pInLimitPtr;
	char *OutPtr ;
			
	pInPtr = pSrc;
	iInMax3 = nSize / 3 * 3;
	OutPtr = pDest;
	pInLimitPtr = pInPtr + iInMax3;
				
	while (pInPtr != pInLimitPtr)
	{
		Len = 0;
		while ((Len < m_LineWidth) && (pInPtr != pInLimitPtr))
		{
			iB = (unsigned char) *pInPtr++;
			iB = iB << 8;
				
			iB = iB | (unsigned char) *pInPtr++;
			iB = iB << 8;
						
			iB = iB | (unsigned char) *pInPtr++;
						
			//以4 byte倒序写入输出缓冲
			OutPtr[3] = BASE64_ENCODE_TABLE[iB & 0x3F];
			iB = iB >> 6;
			OutPtr[2] = BASE64_ENCODE_TABLE[iB & 0x3F];
			iB = iB >> 6;
			OutPtr[1] = BASE64_ENCODE_TABLE[iB & 0x3F];
			iB = iB >> 6;
			OutPtr[0] = BASE64_ENCODE_TABLE[iB];
			OutPtr+=4;
			Len+=4;
		}
		if (Len >= m_LineWidth)
		{
			*OutPtr++ = '\r'; //加上回车换行符
			*OutPtr++ = '\n';
		}
	}
	//设置尾部
	switch (nSize - iInMax3)
	{
		case 1:
			iB = (unsigned char) *pInPtr;
			iB = iB << 4;
			OutPtr[1] = BASE64_ENCODE_TABLE[iB & 0x3F];
			iB = iB >> 6;
			OutPtr[0] = BASE64_ENCODE_TABLE[iB];
			OutPtr[2] = '='; //用'='也就是64码填充剩余部分
			OutPtr[3] = '=';
			OutPtr+=4;
			break;
		case 2:
			iB = (unsigned char) *pInPtr++;
			iB = iB << 8;
			iB = iB | (unsigned char) *pInPtr;
			iB = iB << 2;
			OutPtr[2] = BASE64_ENCODE_TABLE[iB & 0x3F];
			iB = iB >> 6;
			OutPtr[1] = BASE64_ENCODE_TABLE[iB & 0x3F];
			iB = iB >> 6;
			OutPtr[0] = BASE64_ENCODE_TABLE[iB];
			OutPtr[3] = '='; // Fill remaining byte.
			OutPtr+=4;
			break;
	}
	return (unsigned int) (OutPtr - pDest);
}
			
//------------------------------------------------------------------------------
//Base64解码

int CCoder::base64_decode(char *pSrc, unsigned int nSize, char *pDest)
{
	if ((pSrc == NULL) || (pDest == NULL) || (nSize <= 0)) return 0;
			
	unsigned int lByteBuffer, lByteBufferSpace;
	unsigned int C; //临时阅读变量
	int reallen;
	char *InPtr, *InLimitPtr;
	char *OutPtr;
				
	lByteBuffer = 0; lByteBufferSpace = 4;
				
	InPtr = pSrc;
	InLimitPtr= InPtr + nSize;
	OutPtr = pDest;
				
	while (InPtr != InLimitPtr)
	{
		C = BASE64_DECODE_TABLE[*InPtr]; // Read from InputBuffer.
		InPtr++;
		if (C == 0xFF) continue; //读到255非法字符
		lByteBuffer = lByteBuffer << 6 ;
		lByteBuffer = lByteBuffer | C ;
		lByteBufferSpace--;
		if (lByteBufferSpace != 0) continue; //一次读入4个字节
		//到序写入3个字节到缓冲
		OutPtr[2] = lByteBuffer;
		lByteBuffer = lByteBuffer >> 8;
		OutPtr[1] = lByteBuffer;
		lByteBuffer = lByteBuffer >> 8;
		OutPtr[0] = lByteBuffer;
		//准备写入后3位
		OutPtr+= 3; lByteBuffer = 0; lByteBufferSpace = 4;
	}
	reallen = (unsigned int)((long)OutPtr - (long)pDest);
	//处理尾部 返回实际长度
	switch (lByteBufferSpace)
	{
		case 1:
			lByteBuffer = lByteBuffer >> 2;
			OutPtr[1] = lByteBuffer;
			lByteBuffer = lByteBuffer >> 8;
			OutPtr[0] = lByteBuffer;
			return reallen + 2;
		case 2:
			lByteBuffer = lByteBuffer >> 4;
			OutPtr[0] = lByteBuffer;
			return reallen + 1;
		default:
			return reallen;
	}
}

//------------------------------------------------------------------------------


//------------------------------------------------------------------------------

//------------------------------------------------------------------------------

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