base64my.pc

自己编写的BASE64算法

/* base64.c: MIME BASE64编码与解码器,读标准输入. 赵建军, 2000.1.12.a */
/* 2000.2.19.A: 增文件处理. */
#include "stdio.h"
#include "string.h"
#include "stdlib.h"
#include "ctype.h"
char	*sBaseStr="ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
union
{
   struct{
    unsigned long four:6;
    unsigned long three:6;
    unsigned long two:6;
    unsigned long one:6;
   }short_string;
   char	new_other[3];
}union_string;
int	decode=0;

main(int argc,char **argv)
{
  extern char	*optarg;
  extern int	optind;
  char temp_string[500];
  char out_string[500];
  int		i;
  char cChar;
  decode=1;
  memset(&temp_string,0,sizeof(temp_string));
  memset(&out_string,0,sizeof(out_string));
  strcpy(temp_string,"27jrWz2sxrVbR+pnyg6jWHhgNk4sZo46");
  for(i=0;i<strlen(temp_string);i++){
  	cChar=temp_string[i];
  	printf("%c,",cChar);
  	}
  base64decode(temp_string,out_string);
  printf("out string:\n");
  for(i=0;i<strlen(out_string);i++){
  	printf("[%c],[%d]",out_string[i],out_string[i]);
  	} 
  printf("\n");
  

  exit(0);
}
/*编码*/
char *base64encode(char *input,char *output)
{
 char	cString;
 char sTemp[1000];
 char sTmp[10];
 int i,n;
 memset(&sTemp,0,sizeof(sTemp));
 strcpy(sTemp,input);
 for(i=0;i<strlen(sTemp);i+=3)
 {
  union_string.new_other[0]=union_string.new_other[1]=union_string.new_other[2]=0;
  for (n=0;n<3;n++)
  {
   cString=sTemp[i+n];
   if (cString==EOF) break;
   union_string.new_other[2-n]=cString;
  }
  if (n==0) break;
  switch(n)
  {
   case 1: 
      memset(&sTmp,0,sizeof(sTmp));
      sprintf(sTmp,"%c%c==",sBaseStr[union_string.short_string.one],sBaseStr[union_string.short_string.two]);
      strcat(sTemp,sTmp);
      break;
   case 2: 
      memset(&sTmp,0,sizeof(sTmp));
      sprintf(sTmp,"%c%c%c=",sBaseStr[union_string.short_string.one],sBaseStr[union_string.short_string.two],sBaseStr[union_string.short_string.three]);
      strcat(sTemp,sTmp);
      break;
   case 3: 
      memset(&sTmp,0,sizeof(sTmp));
      sprintf(sTmp,"%c%c%c%c",sBaseStr[union_string.short_string.one],sBaseStr[union_string.short_string.two],sBaseStr[union_string.short_string.three],sBaseStr[union_string.short_string.four]);
      strcat(sTemp,sTmp);
      break;
  }
 }
 strcpy(output,sTemp);
 return(output);
}

/*解码*/
char *base64decode(char *input,char *output)
{
 char cStr1,cStr2,cStr3,cStr4;
 char sTmp[10];
 char sTemp[1000];
 char sReturn[1000];
 int i;
 memset(&sTemp,0,sizeof(sTemp));
 memset(&sReturn,0,sizeof(sReturn));
 strcpy(sTemp,input);
 for(i=0;i<strlen(sTemp);i+=4){
  cStr1=sTemp[i];
  printf("cStr1:[%02X],cStr1:[%c]\n",cStr1,cStr1);
  if (cStr1==EOF||cStr1=='\n'||cStr1=='\0'){
  	 break;
  }
  
  if (strchr(sBaseStr,cStr1)==NULL&&cStr1!='=')
  {
   printf("Error: %c : not BASE64 code!\n",cStr1);
   strcpy(output,"");
   return output;
  }
  cStr2=sTemp[i+1];
  printf("cStr2:[%02X],cStr2:[%c]\n",cStr2,cStr2);
  if (cStr2==EOF)
  {
   printf("Error: unexpected EOF in BASE64 code!\n");
   strcpy(output,"");
   return output;
  }
  if (strchr(sBaseStr,cStr2)==NULL&&cStr2!='=')
  {
   printf("Error: %c : not BASE64 code!\n",cStr2);
   strcpy(output,"");
   return output;
  }
  cStr3=sTemp[i+2];
  printf("cStr3:[%02X],cStr3:[%c]\n",cStr3,cStr3);
  if (cStr3==EOF)
  {
   printf("Error: unexpected EOF in BASE64 code!\n");
   strcpy(output,"");
   return output;
  }
  if (strchr(sBaseStr,cStr3)==NULL&&cStr3!='=')
  {
   printf("Error: %c : not BASE64 code!\n",cStr3);
   strcpy(output,"");
   return output;
  }
  cStr4=sTemp[i+3];
  if (cStr4==EOF)
  {
   printf("Error: unexpected EOF in BASE64 code!\n");
   strcpy(output,"");
   return output;
  }
  if (strchr(sBaseStr,cStr4)==NULL&&cStr4!='=')
  {
   printf("Error: %c : not BASE64 code!\n",cStr4);
   strcpy(output,"");
   return output;
  }
  if (strchr(sBaseStr,cStr1)&&strchr(sBaseStr,cStr2)&&(strchr(sBaseStr,cStr3)||cStr3=='=')&&
  	((cStr3=='='&&cStr4=='=')||(cStr3!='='&&(cStr4=='='||strchr(sBaseStr,cStr4)))))
  {
   union_string.short_string.one=strchr(sBaseStr,cStr1)-sBaseStr;
   union_string.short_string.two=strchr(sBaseStr,cStr2)-sBaseStr;
   if (cStr3=='=')
   {
    memset(&sTmp,0,sizeof(sTmp));
    sprintf(sTmp,"%c",union_string.new_other[2]);
    strcat(sReturn,sTmp);
   }
   else
   if (cStr4=='=')
   {
    union_string.short_string.three=strchr(sBaseStr,cStr3)-sBaseStr;
    memset(&sTmp,0,sizeof(sTmp));
    sprintf(sTmp,"%c%c",union_string.new_other[2],union_string.new_other[1]);
    strcat(sReturn,sTmp);
   }
   else
   {
    union_string.short_string.three=strchr(sBaseStr,cStr3)-sBaseStr;
    union_string.short_string.four=strchr(sBaseStr,cStr4)-sBaseStr;
    memset(&sTmp,0,sizeof(sTmp));
    sprintf(sTmp,"%c%c%c",union_string.new_other[2],union_string.new_other[1],union_string.new_other[0]);
    strcat(sReturn,sTmp);    
   }
  }
  else
  {
   printf("Error: %c%c%c%c : not BASE64 code!\n",cStr1,cStr2,cStr3,cStr4);
   strcpy(output,"");
   return output;
  }
 }

 strcpy(output,sReturn);
 return(output);
}