关于UrlEncode的实现(C++)。网上有非常多不同的版本号。对须要编码的字符集的选取并不统一。那么究竟有没有标准呢？答案是有的。參见wiki
绝对不编码的，仅仅有字母、数字、短横线(-)、下划线(_)、点(.)和波浪号(~)，其它字符要视情况而定。所以一般性的urlencode仅仅需保留上述字符不进行编码。
以下给出实现：
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unsigned char ToHex(unsigned char x)
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{
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return x > 9 ? x + 55 : x + 48;
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}
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unsigned char FromHex(unsigned char x)
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{
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unsigned char y;
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if (x >= ‘A‘ && x <= ‘Z‘) y = x - ‘A‘ + 10;
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else if (x >= ‘a‘ && x <= ‘z‘) y = x - ‘a‘ + 10;
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else if (x >= ‘0‘ && x <= ‘9‘) y = x - ‘0‘;
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else assert(0);
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return y;
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}
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std::string UrlEncode(const std::string& str)
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{
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std::string strTemp = "";
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size_t length = str.length();
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for (size_t i = 0; i < length; i++)
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{
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if (isalnum((unsigned char)str[i]) ||
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(str[i] == ‘-‘) ||
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(str[i] == ‘_‘) ||
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(str[i] == ‘.‘) ||
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(str[i] == ‘~‘))
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strTemp += str[i];
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else if (str[i] == ‘ ‘)
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strTemp += "+";
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else
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{
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strTemp += ‘%‘;
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strTemp += ToHex((unsigned char)str[i] >> 4);
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strTemp += ToHex((unsigned char)str[i] % 16);
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}
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}
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return strTemp;
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}
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std::string UrlDecode(const std::string& str)
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{
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std::string strTemp = "";
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size_t length = str.length();
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for (size_t i = 0; i < length; i++)
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{
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if (str[i] == ‘+‘) strTemp += ‘ ‘;
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else if (str[i] == ‘%‘)
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{
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assert(i + 2 < length);
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unsigned char high = FromHex((unsigned char)str[++i]);
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unsigned char low = FromHex((unsigned char)str[++i]);
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strTemp += high*16 + low;
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}
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else strTemp += str[i];
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}
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return strTemp;
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}
