RFC3986编码 C 语言实现(支持大部分中文)

#include <stdlib.h>
#include <string.h>
#include <stdio.h>
#include <android/log.h>
#include "RFC3986Encoder.h"




bool isReverseChar(char c);
char* charToHexString(char c);
bool isChinese(char c);




//#define snprintf _snprintf
/**
 * 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.
 */


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

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




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

char *xstrdup (const char *s) {
  void *ptr = xmalloc(strlen(s)+1);
  strcpy((char *)ptr, s);
  return (char*)ptr;
}




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;
      }     
      
      //转换成16进制.  58-->3A
      //%3A  这是3个.这里好像是自动  加 ‘/0‘  如果生成的的字符串,大于4则不会,自动加/0
      //在linux 下,这个方法,的count 包括  ‘/0‘所以最后的结果也是正确的.
       
      int result = snprintf(&ns[strindex], 4, "%%%02X", in);    
       
      /*
      printf("%d\n",result);
      
      printf("%d\n",in);
      
      printf("strlen(buf) = %d\n",strlen(ns));    
      printf("%s\n",ns);
      */

      strindex+=3;
      break;
    }
    string++;
  }
  ns[strindex]=0;
  return ns;
}

#ifndef ISXDIGIT
# define ISXDIGIT(x) (isxdigit((int) ((unsigned char)x)))
#endif


//自己写的代码  3
char* rfc3986Encoder(const char* input)
{
    //__android_log_print(ANDROID_LOG_INFO, "Test_jni","encoder start %s\n", input);

    if (!input) return xstrdup("");


    //char* sb = (char*)malloc(1024);
    char* sb = new char[1024];
    sb[0]= ‘\0‘;
    int length =  strlen(input);
    for (int i = 0; i<length; i++)
    {
        char c = input[i];
        if(isReverseChar(c)){
            const char* temp;
            if(isChinese(c))
            {
                //这里认为汉字 utf-8为三字节,首位为连续三个1,取unicode的后8位
                //这里相于 utf-8 到 unicode 的转换,只是转换了后8位.
                int high = (input[i+1]&0x03)<<6;
                int low = input[i+2]&0x3f;
                char chinese = (high+low)&0xff;
                temp = charToHexString(chinese);
                i+=2;
            }else{
                temp = charToHexString(c);
            }
            strcat(sb,temp);
        }
        else{
            int len = strlen(sb);
            const char*  p =  &c;  //字符看不到结束符,所以会错.
            strcat(sb,p);
            sb[len+1] = ‘\0‘;
        }
    }
    //__android_log_print(ANDROID_LOG_INFO, "Test_jni","encoder end  %s\n", sb);
    return sb;
}

bool isReverseChar(char c)
{
    return !((c >= ‘a‘ && c <= ‘z‘) || (c >= ‘A‘ && c <= ‘Z‘) || (c >= ‘0‘ && c <= ‘9‘)
                    || c == ‘-‘ || c == ‘_‘ || c == ‘.‘ || c == ‘~‘);
}

char* charToHexString(char src){
   int v = src & 0xFF;
   char* hv = new char[4];
   snprintf(hv, 4,"%%%02X",v);
   return hv ;
}
bool isChinese(char c)
{
    int x = c&0xE0;
    if(x == 224)
        return true;
    else
        return false;
}