base64.cpp

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

#include "StdAfx.h"
#include "Base64.h"

char base64EncodeChars[65] ="ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";//编码后的字符集
int  base64DecodeChars[128]={-1, -1, -1, -1, -1, -1, -1, -1,
							 -1, -1, -1, -1, -1, -1, -1, -1,
							 -1, -1, -1, -1, -1, -1, -1, -1,
							 -1, -1, -1, -1, -1, -1, -1, -1, 
							 -1, -1, -1, -1, -1, -1, -1, -1, 
							 -1, -1, -1, 62, -1, -1, -1, 63, 
							 52, 53, 54, 55, 56, 57, 58, 59, 
							 60, 61, -1, -1, -1, -1, -1, -1, 
							 -1,  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, -1, -1, -1, -1, -1,
							 -1, 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, -1, -1, -1, -1, -1 };//对应ASICC字符的位置

char* base64encode(LPCTSTR str)
{ //加密
	char Out[260]={0};
	int i = 0, len = strlen(str);
	char c1, c2, c3;
	while (i < len)
	{
		c1 = str[i++] & 0xff;
		if (i == len)
		{
			sprintf(Out,"%s%c",Out,base64EncodeChars[c1 >> 2]);
			sprintf(Out,"%s%c",Out,base64EncodeChars[(c1 & 0x3) << 4]);
			sprintf(Out,"%s==",Out);
			break;
		}
		c2 = str[i++];
		if (i == len)
		{
			sprintf(Out,"%s%c",Out,base64EncodeChars[c1 >> 2]);
			sprintf(Out,"%s%c",Out,base64EncodeChars[((c1 & 0x3) << 4) | ((c2 & 0xF0) >> 4)]);
			sprintf(Out,"%s%c",Out,base64EncodeChars[(c2 & 0xF) << 2]);
			sprintf(Out,"%s==",Out);
			break;
		}
		c3 = str[i++];
		sprintf(Out,"%s%c",Out,base64EncodeChars[c1 >> 2]);
		sprintf(Out,"%s%c",Out,base64EncodeChars[((c1 & 0x3) << 4) | ((c2 & 0xF0) >> 4)]);
		sprintf(Out,"%s%c",Out,base64EncodeChars[((c2 & 0xF) << 2) | ((c3 & 0xC0) >> 6)]);
		sprintf(Out,"%s%c",Out,base64EncodeChars[c3 & 0x3F]);
	}
	return &(*Out);
}
char* utf16to8(LPCTSTR str)
{
	char Out[260] ={0};
	int i, len;
	char c;//char为16位Unicode字符,范围0~0xffff,
	len = strlen(str);
	for (i = 0; i < len; i++)
	{//根据字符的不同范围分别转化
		c = str[i];
		if ((c >= 0x0001) && (c <= 0x007F))
		{
			sprintf(Out,"%s%c",Out,str[i]);
		}
		else if (c > 0x07FF)
		{
			sprintf(Out,"%s%c",Out,(0xE0 | ((c >> 12) & 0x0F)));
			sprintf(Out,"%s%c",Out,(0xE0 | ((c >> 12) & 0x0F)));
			sprintf(Out,"%s%c",Out,(0x80 | ((c >> 6) & 0x3F)));
			sprintf(Out,"%s%c",Out,(0x80 | ((c >> 0) & 0x3F)));
		}
		else
		{
			sprintf(Out,"%s%c",Out,(0xC0 | ((c >> 6) & 0x1F)));
			sprintf(Out,"%s%c",Out,(0x80 | ((c >> 0) & 0x3F)));
		}
	}
	return &(*Out);
}

char* base64decode(LPCTSTR str)
{//解密
	int c1, c2, c3, c4;
	int i=0, len;
	char Out[260]={0};
	len = strlen(str);
	while (i < len)
	{
		do
		{
			c1 = base64DecodeChars[str[i++] & 0xff];
		} while (i < len && c1 == -1);
		if (c1 == -1) break;
		do
		{
			c2 = base64DecodeChars[str[i++] & 0xff];
		} while (i < len && c2 == -1);
		if (c2 == -1) break;
		sprintf(Out,"%s%c",Out,((c1 << 2) | ((c2 & 0x30) >> 4)));
		do
		{
			c3 = str[i++] & 0xff;
			if (c3 == 61) return Out;
			c3 = base64DecodeChars[c3];
		} while (i < len && c3 == -1);
		if (c3 == -1) break;
		sprintf(Out,"%s%c",Out,((c2 & 0XF) << 4) | ((c3 & 0x3C) >> 2));
		do
		{
			c4 = str[i++] & 0xff;
			if (c4 == 61) return Out;
			c4 = base64DecodeChars[c4];
		} while (i < len && c4 == -1);
		if (c4 == -1) break;
		sprintf(Out,"%s%c",Out,((c3 & 0x03) << 6) | c4);
	}
	return &(*Out);
}

char* utf8to16(LPCTSTR str)
{
	char Out[260]={0};
	int i=0, len;
	char c, char2, char3;
	len = strlen(str);
	 while (i < len)
	{
		c = str[i++];
		switch (c >> 4)
		{
		case 0:
		case 1:
		case 2:
		case 3:
		case 4:
		case 5:
		case 6:
		case 7: 
			sprintf(Out,"%s%c",Out,str[i - 1]);
			break;
		case 12:
		case 13: char2 = str[i++];
			sprintf(Out,"%s%c",Out,(((c & 0x1F) << 6) | (char2 & 0x3F)));
			break;
		case 14: char2 = str[i++];
			char3 = str[i++];
			sprintf(Out,"%s%c",Out,(((c & 0x0F) << 12) | ((char2 & 0x3F) << 6) | ((char3 & 0x3F) << 0)));
			break;
		}
	}
	return &(*Out);
}