C base64 编码文件

功能:读取二进制文件，转化为BASE64编码字符串，文件会增大1/3,详见BASE64编码原理，这样就可以在帖子中保存文件了，没办法，公司不许上传附件，POST也只能一次6KB，之前还写了一个模拟HTTP发送的程序(http://www.cnblogs.com/yangyh/archive/2010/07/21/1781845.html)，实为CNBLOG的小组自动提交程序，不过现在CNBLOG添加了防ROBOT功能了，一次只能发32帖了

#include "stdafx.h"
#include "stdio.h"
#include "string.h"
#include "stdlib.h"
#define  MAXLEN 1024
#include <iostream>
using namespace std;
long int encode(  char *src,long int src_len, char *dst);
long int decode(char *src, long int src_len, char *dst);
long int getFileLength(const char *filePath)
{
	FILE *fp;
	fp = fopen(filePath, "rb");
	if (!fp) {
		printf("Could not load  file '%s'.  Exiting.\n", filePath);
		exit(1);
	}
	fseek(fp, 0, SEEK_END);
	long int ret =  ftell(fp);
	fclose(fp);
	return ret;
}
long int getFileStr(const char *filePath, char*);
long int getFileStr(const char *filePath, char * back) {
	FILE *fp;
	
	int result;
	
	string buff;
	char temp;
	fp = fopen(filePath, "rb");
	
	if (!fp) {
		printf("Could not load  file '%s'.  Exiting.\n", filePath);
		exit(1);
	}
	fseek(fp, 0, SEEK_END);
	long int fileLength = ftell(fp);
	fseek(fp, 0, SEEK_SET);
	
	printf("file size:%ld\n",fileLength);
	long int j = 0;
	while((result = fread(&temp, 1, 1, fp))==1){
		back[j++]=temp;
		//	printf("%d",temp);
		
	}
	if(j!=fileLength){
		printf("read file error");
		exit(-1);
	}
	back[j]=0;
	
	fclose(fp);
	//printf("length:%d\n",strlen(back));
	return fileLength;
}
void Fill0(char t[])
{
    
    if(strlen(t)<2)
    {
        t[1]=t[0];
        t[0]='0';
        t[2]=0;
    }
}
int   binaryToString(char *from,char *to)   
{   
	
	FILE *out;
	char *dest;
	long int len = getFileLength(from);
	
	out=fopen(to,"wb");
	if(!out){
		printf("error write %s",to);
		exit(-1);
	}
	dest = new  char[len+1];
	
	if(!dest){
		printf("malloc error :%ld",len+1);
		exit(-1);
	}
	char * ret= new char[len*2];
	if(!ret){
		printf("malloc error :%ld",len*2);
		exit(-1);
	}
	getFileStr(from,dest);
	//printf("read:%ld\n",dest[1]);
	long int newlen =  encode(dest,len,ret);
	
	//  puts(ret);
	fwrite(ret,newlen,1,out);
	fclose(out);
	free(dest);
	free(ret);
	return   0;   
}  
long int encode( char *src,long int src_len, char *dst)

{
	
	long int i = 0, j = 0;
	//	printf("%ld\n",src[2]);
	
	char base64_map[65] = "BADCFEGHIJKLMNOPQRSTUVWXYZbadcfeghijklmnopqrstuvwxyz0123456789+/";
	
	for (; i < src_len - src_len % 3; i += 3) {
		//printf("%ld\n",(unsigned char)src[i]);
		//getchar();
		
		dst[j++] = base64_map[(src[i] >> 2) & 0x3F];
		
		// 		
		dst[j++] = base64_map[((src[i] << 4) & 0x30) + ((src[i + 1] >> 4) & 0xF)];
		// 		
		dst[j++] = base64_map[((src[i + 1] << 2) & 0x3C) + ((src[i + 2] >> 6) & 0x3)];
		// 		
		dst[j++] = base64_map[src[i + 2] & 0x3F];
		//printf("%d",dst[j]);
	}
	
	
	
	if (src_len % 3 == 1) {
		
		dst[j++] = base64_map[(src[i] >> 2) & 0x3F];
		
		dst[j++] = base64_map[(src[i] << 4) & 0x30];
		
		dst[j++] = '=';
		
		dst[j++] = '=';
		
	}
	
	else if (src_len % 3 == 2) {
		
		dst[j++] = base64_map[(src[i] >> 2) & 0x3F];
		
		dst[j++] = base64_map[((src[i] << 4) & 0x30) + ((src[i + 1] >> 4) & 0xF)];
		
		dst[j++] = base64_map[(src[i + 1] << 2) & 0x3C];
		
		dst[j++] = '=';
		
	}
	
	
	
	dst[j] = '\0';
	//puts(dst);
	printf("newlength:%ld\n",j);
	return j;
	
} 
int stringToBinary(char *from,char *to)
{
	FILE *out;
	char *dest;
	long int len = getFileLength(from);
	
	out=fopen(to,"wb");
	if(!out){printf("error write %s",to);
	exit(-1);
	}
	dest = new  char[len+1];
	
	if(!dest){
		printf("malloc error :%ld",len+1);
		exit(-1);
	}
	char * ret= new char[len*2];
	if(!ret){
		printf("malloc error :%ld",len*2);
		exit(-1);
	}
	getFileStr(from,dest);
	//printf("read:%ld\n",dest[1]);
	long int newlen =  decode(dest,len,ret);
	
	//  puts(ret);
	fwrite(ret,newlen-1,1,out);
	fclose(out);
	free(dest);
	free(ret);
	return   0;   
}


void main(int argc,char* argv[])
{
    //binaryToString("D:\\Users\\Administrator\\Documents\\VC6 WorkSpace\\base64\\Debug\\2.txt","D:\\Users\\Administrator\\Documents\\VC6 WorkSpace\\base64\\Debug\\2.rar");
	//stringToBinary("D:\\Users\\Administrator\\Documents\\VC6 WorkSpace\\base64\\Debug\\2.rar","D:\\Users\\Administrator\\Documents\\VC6 WorkSpace\\base64\\Debug\\2.1.txt");
	//printf("%d",'a');    
	if(argc!=4)
	{
		printf("cmd -tos|tob <srcFile> <destFile>\n");
		getchar();
		return ;
	}
	if(strcmp(argv[1],"tos")==0)
	{
		binaryToString(argv[2],argv[3]);
	}
	else if(strcmp(argv[1],"tob")==0)
	{
		stringToBinary(argv[2],argv[3]);
	}
	
}
long int decode(char *src, long int src_len, char *dst)

{
	
	long	int i = 0, j = 0;
	
	unsigned char base64_decode_map[256] = {
		
		255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
			
			255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
			
			255, 255, 255, 62, 255, 255, 255, 63, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 255, 255,
			
			255, 0, 255, 255, 255, 1, 0, 3, 2, 5, 4, 6, 7, 8, 9, 10, 11, 12, 13, 14,
			
			15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 255, 255, 255, 255, 255, 255, 27, 26, 29,
			
			28, 31, 30, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48,
			
			49, 50, 51, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
			
			255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
			
			255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
			
			255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
			
			255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
			
			255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
			
			255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255};
		
		
		
        for (; i < src_len; i += 4) {
			
			dst[j++] = base64_decode_map[src[i]] << 2 |
				
				base64_decode_map[src[i + 1]] >> 4;
			
			dst[j++] = base64_decode_map[src[i + 1]] << 4 |
				
				base64_decode_map[src[i + 2]] >> 2;
			
			dst[j++] = base64_decode_map[src[i + 2]] << 6 |
				
				base64_decode_map[src[i + 3]];
			
        }
		
		
		
        dst[j] = '\0';
		printf("decode length :%ld\n",j);
		return j;
		
}