URL encode C 实现

  今天要做点东西， 需要用到URL编码， 找到的几个例子在解析中文的时候遇到点困难，一下是在 sina api c++ sdk 中挑选出来的  做了一下 测试 希望对后来人有所帮助：

 

 #include <stdio.h>#include <stdlib.h>#include <string.h>

static void *xmalloc_fatal(size_t size) {  if (size==0) return NULL;  fprintf(stderr, "Out of memory.");  exit(1);  return 0;}

void *xmalloc (size_t size) {  void *ptr = malloc (size);  if (ptr == NULL) return xmalloc_fatal(size);  return ptr;}

void *xcalloc (size_t nmemb, size_t size) {  void *ptr = calloc (nmemb, size);  if (ptr == NULL) return xmalloc_fatal(nmemb*size);  return ptr;}

void *xrealloc (void *ptr, size_t size) {  void *p = realloc (ptr, size);  if (p == NULL) return xmalloc_fatal(size);  return p;}

char *xstrdup (const char *s) {  void *ptr = xmalloc(strlen(s)+1);  strcpy (ptr, s);  return (char*) ptr;}/** * Escape 'string' according to RFC3986 and * http://oauth.net/core/1.0/#encoding_parameters. * * @param string The data to be encoded * @return encoded string otherwise NULL * The caller must free the returned string. */char *oauth_url_escape(const char *string) {  size_t alloc, newlen;  char *ns = NULL, *testing_ptr = NULL;  unsigned char in;   size_t strindex=0;  size_t length;

  if (!string) return xstrdup("");

  alloc = strlen(string)+1;  newlen = alloc;

  ns = (char*) xmalloc(alloc);

  length = alloc-1;  while(length--) {    in = *string;

    switch(in){    case '0': case '1': case '2': case '3': case '4':    case '5': case '6': case '7': case '8': case '9':    case 'a': case 'b': case 'c': case 'd': case 'e':    case 'f': case 'g': case 'h': case 'i': case 'j':    case 'k': case 'l': case 'm': case 'n': case 'o':    case 'p': case 'q': case 'r': case 's': case 't':    case 'u': case 'v': case 'w': case 'x': case 'y': case 'z':    case 'A': case 'B': case 'C': case 'D': case 'E':    case 'F': case 'G': case 'H': case 'I': case 'J':    case 'K': case 'L': case 'M': case 'N': case 'O':    case 'P': case 'Q': case 'R': case 'S': case 'T':    case 'U': case 'V': case 'W': case 'X': case 'Y': case 'Z':    case '_': case '~': case '.': case '-':      ns[strindex++]=in;      break;    default:      newlen += 2; /* this'll become a %XX */      if(newlen > alloc) {        alloc *= 2;        testing_ptr = (char*) xrealloc(ns, alloc);        ns = testing_ptr;      }      snprintf(&ns[strindex], 4, "%%X", in);      strindex+=3;      break;    }    string++;  }  ns[strindex]=0;  return ns;}

int main(int argc, char *argv[]){  char src[1024];   char* sb;  strcpy(src,"http://www.google.com/?=春节1234");  sb= malloc(5*strlen(src));  sb = oauth_url_escape(src);

        printf("url %s/n src:%d-dest:%d/n",src,strlen(src),strlen(sb));        printf("encoded url %s",sb);

  system("PAUSE");   free(sb);  return 0;}