MIME之Quoted-Printable编解码

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P.bhw98 { PADDING-RIGHT: 0px; PADDING-LEFT: 0px; FONT-SIZE: 9pt; PADDING-BOTTOM: 0px; MARGIN: 10px 0px 5px; LINE-HEIGHT: normal; PADDING-TOP: 0px; FONT-FAMILY: Verdana, Arial } PRE.bhw98 { FONT-SIZE: 9pt; PADDING-RIGHT: 5px; PADDING-LEFT: 5px; PADDING-BOTTOM: 5px; MARGIN: 5px 0px; LINE-HEIGHT: normal; PADDING-TOP: 5px; BACKGROUND-COLOR: #f0f0f0 } PRE.diag { FONT-SIZE: 9pt; PADDING-RIGHT: 5px; PADDING-LEFT: 5px; PADDING-BOTTOM: 5px; MARGIN: 5px 0px; LINE-HEIGHT: normal; PADDING-TOP: 5px; } CODE.bhw98 { FONT-SIZE: 9pt; COLOR: #000000 } TABLE.bhw98 { BORDER-RIGHT: #808080 1px solid; BORDER-TOP: #808080 1px solid; FONT-SIZE: 9pt; MARGIN: 3px 0px 10px; BORDER-LEFT: #808080 1px solid; LINE-HEIGHT: normal; BORDER-BOTTOM: #808080 1px solid; FONT-FAMILY: Verdana, Arial } TD.bhw98 { BORDER-RIGHT: darkgray 1px solid; PADDING-RIGHT: 10px; BORDER-TOP: darkgray 1px solid; PADDING-LEFT: 5px; FONT-SIZE: 9pt; PADDING-BOTTOM: 0px; MARGIN: 0px; BORDER-LEFT: darkgray 1px solid; LINE-HEIGHT: normal; PADDING-TOP: 3px; BORDER-BOTTOM: darkgray 1px solid; FONT-FAMILY: Verdana, Arial; BACKGROUND-COLOR: #f0f0f0 } STRONG.bhw98 { FONT-WEIGHT: bolder; FONT-SIZE: 20pt; COLOR: #228b22; FONT-STYLE: italic; FONT-FAMILY: Verdana, Arial } LI.bhw98 { FONT-SIZE: 9pt; MARGIN: 3px 0px 0px 3px; LINE-HEIGHT: normal; FONT-FAMILY: Verdana, Arial } H1.bhw98 { MARGIN-TOP: 25px; FONT-WEIGHT: bolder; FONT-SIZE: 12pt; MARGIN-BOTTOM: 5px; LINE-HEIGHT: normal; FONT-FAMILY: Verdana, Arial } H2.bhw98 { MARGIN-TOP: 20px; FONT-WEIGHT: bolder; FONT-SIZE: 10.5pt; MARGIN-BOTTOM: 5px; LINE-HEIGHT: normal; FONT-FAMILY: Verdana, Arial } H3.bhw98 { MARGIN-TOP: 15px; FONT-WEIGHT: bolder; FONT-SIZE: 9pt; MARGIN-BOTTOM: 5px; LINE-HEIGHT: normal; FONT-FAMILY: Verdana, Arial } SPAN.key { COLOR: #0000ff } SPAN.num { COLOR: #800000 } SPAN.str { COLOR: #8b008b } SPAN.rem { COLOR: #008000 }

Quoted-Printable也是MIME邮件中常用的编码方式之一。同Base64一样,它也将输入的字符串或数据编码成全是ASCII码的可打印字符串。

Quoted-Printable编码的基本方法是:输入数据在33-60、62-126范围内的,直接输出;其它的需编码为“=”加两个字节的HEX码(大写)。为保证输出行不超过规定长度,可在行尾加“=\r\n”序列作为软回车。

int EncodeQuoted(const unsigned char* pSrc, char* pDst, int nSrcLen, int nMaxLineLen) { int nDstLen; // 输出的字符计数 int nLineLen; // 输出的行长度计数 nDstLen = 0; nLineLen = 0; for (int i = 0; i < nSrcLen; i++, pSrc++) { // ASCII 33-60, 62-126原样输出,其余的需编码 if ((*pSrc >= '!') && (*pSrc = nMaxLineLen - 3) { sprintf(pDst, "=\r\n"); pDst += 3; nDstLen += 3; nLineLen = 0; } } // 输出加个结束符 *pDst = '\0'; return nDstLen; }

Quoted-Printable解码很简单,将编码过程反过来就行了。

int DecodeQuoted(const char* pSrc, unsigned char* pDst, int nSrcLen) { int nDstLen; // 输出的字符计数 int i; i = 0; nDstLen = 0; while (i < nSrcLen) { if (strncmp(pSrc, "=\r\n", 3) == 0) // 软回车,跳过 { pSrc += 3; i += 3; } else { if (*pSrc == '=') // 是编码字节 { sscanf(pSrc, "=%02X", pDst); pDst++; pSrc += 3; i += 3; } else // 非编码字节 { *pDst++ = (unsigned char)*pSrc++; i++; } nDstLen++; } } // 输出加个结束符 *pDst = '\0'; return nDstLen; }

  [相关资源] RFC/STD文档:Internet FAQ Archives bhw98的专栏:http://www.csdn.net/develop/author/netauthor/bhw98/

首次发布: 2003-06-23
最后修订: 2003-06-23

 

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