url编码解码
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c语言的url转码解码
url提交信息为何要转码呢?因为url本身会有很多特殊字符。而提交的参数中如果再有特殊字符的话,url就不能区分哪些是参数内容,哪些是分隔符。尤其是unicode,gb18030,big5等多字节的编码,不知道里面会隐藏什么字节,因此必须全部转码。
好像C语言里面没有现成的转码函数。参考http://blog.csdn.net/wudishine/article/details/39025407,从php的转码中引出两个函数,进行转码。
字符'a'-'z','A'-'Z','0'-'9','.','-','*'和'_' 都不被编码,维持原值;
空格' '被转换为加号'+'。
其他每个字节都被表示成"%XY"的格式,X和Y分别代表一个十六进制位。编码为UTF-8。
下面是一个例子:
#include <stdio.h>#include <string.h>#define BURSIZE 2048int hex2dec(char c){ if ('0' <= c && c <= '9') { return c - '0'; } else if ('a' <= c && c <= 'f') { return c - 'a' + 10; } else if ('A' <= c && c <= 'F') { return c - 'A' + 10; } else { return -1; }}char dec2hex(short int c){ if (0 <= c && c <= 9) { return c + '0'; } else if (10 <= c && c <= 15) { return c + 'A' - 10; } else { return -1; }}//编码一个urlvoid urlencode(char url[]){ int i = 0; int len = strlen(url); printf("%d\n",len); int res_len = 0; char res[BURSIZE]; for (i = 0; i < len; ++i) { char c = url[i]; if ( ('0' <= c && c <= '9') || ('a' <= c && c <= 'z') || ('A' <= c && c <= 'Z') || c == '/' || c == '.') { res[res_len++] = c; } else { int j = (short int)c; printf("%d\n",j); if (j < 0) j += 256; int i1, i0; i1 = j / 16; i0 = j - i1 * 16; res[res_len++] = '%'; res[res_len++] = dec2hex(i1); res[res_len++] = dec2hex(i0); } } res[res_len] = '\0'; strcpy(url, res);}// 解码urlvoid urldecode(char url[]){ int i = 0; int len = strlen(url); int res_len = 0; char res[BURSIZE]; for (i = 0; i < len; ++i) { char c = url[i]; if (c != '%') { res[res_len++] = c; } else { char c1 = url[++i]; char c0 = url[++i]; int num = 0; num = hex2dec(c1) * 16 + hex2dec(c0); res[res_len++] = num; } } res[res_len] = '\0'; strcpy(url, res);}int main(int argc, char *argv[]){ // char url[100] = "http://'测试/@mike"; char url[100] = "'测试"; urlencode(url); //编码后 // printf("http://'测试/@mike ----> %s\n", url); printf("----> %s\n", url); // char buf[100] = "http%3A//%27%E6%B5%8B%E8%AF%95/%40mike"; char buf[100] = "%B4%F3%B3%A7"; urldecode(buf); //解码后 //printf("http%%3A//%%27%%E6%%B5%%8B%%E8%%AF%%95/%%40mike ----> %s\n", buf); printf("----> %s\n", buf); return 0;}