在LoadRunner中进行Base64的编码和解码

《Base64 Encode/Decode for LoadRunner》这篇文章介绍了如何在LoadRunner中对字符串进行Base64的编码和解码：

http://ptfrontline.wordpress.com/2009/09/30/base64-encodedecode-for-loadrunner/

在头文件中封装b64_encode_string和b64_decode_string函数：

/*
Base 64 Encode and Decode functions for LoadRunner
==================================================
This include file provides functions to Encode and Decode
LoadRunner variables. It's based on source codes found on the
internet and has been modified to work in LoadRunner.

Created by Kim Sandell / Celarius - www.celarius.com
*/
// Encoding lookup table
char base64encode_lut[] = {
'A','B','C','D','E','F','G','H','I','J','K','L','M','N','O','P','Q',
'R','S','T','U','V','W','X','Y','Z','a','b','c','d','e','f','g','h',
'i','j','k','l','m','n','o','p','q','r','s','t','u','v','w','x','y',
'z','0','1','2','3','4','5','6','7','8','9','+','/','='};

// Decode lookup table
char base64decode_lut[] = {
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0,62, 0, 0, 0,63,52,53,54,55,56,57,58,59,60,61, 0, 0,
0, 0, 0, 0, 0, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9,10,11,12,13,14,
15,16,17,18,19,20,21,22,23,24,25, 0, 0, 0, 0, 0, 0,26,27,28,
29,30,31,32,33,34,35,36,37,38,39,40,41,42,43,44,45,46,47,48,
49,50,51, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, };

void base64encode(char *src, char *dest, int len)
// Encodes a buffer to base64
{
 int i=0, slen=strlen(src);
 for(i=0;i<slen && i<len;i+=3,src+=3)
 { // Enc next 4 characters
 *(dest++)=base64encode_lut[(*src&0xFC)>>0x2];
 *(dest++)=base64encode_lut[(*src&0x3)<<0x4|(*(src+1)&0xF0)>>0x4];
 *(dest++)=((i+1)<slen)?base64encode_lut[(*(src+1)&0xF)<<0x2|(*(src+2)&0xC0)>>0x6]:'=';
 *(dest++)=((i+2)<slen)?base64encode_lut[*(src+2)&0x3F]:'=';
 }
 *dest='/0'; // Append terminator
}

void base64decode(char *src, char *dest, int len)
// Encodes a buffer to base64
{
 int i=0, slen=strlen(src);
 for(i=0;i<slen&&i<len;i+=4,src+=4)
 { // Store next 4 chars in vars for faster access
 char c1=base64decode_lut[*src], c2=base64decode_lut[*(src+1)], c3=base64decode_lut[*(src+2)], c4=base64decode_lut[*(src+3)];
 // Decode to 3 chars
 *(dest++)=(c1&0x3F)<<0x2|(c2&0x30)>>0x4;
 *(dest++)=(c3!=64)?((c2&0xF)<<0x4|(c3&0x3C)>>0x2):'/0';
 *(dest++)=(c4!=64)?((c3&0x3)<<0x6|c4&0x3F):'/0';
 }
 *dest='/0'; // Append terminator
}

int b64_encode_string( char *source, char *lrvar )
// ----------------------------------------------------------------------------
// Encodes a string to base64 format
//
// Parameters:
//&nbsp;&nbsp; &nbsp;&nbsp;&nbsp; &nbsp;source&nbsp;&nbsp;&nbsp; Pointer to source string to encode
//&nbsp;&nbsp; &nbsp;&nbsp;&nbsp; &nbsp;lrvar&nbsp;&nbsp;&nbsp;&nbsp; LR variable where base64 encoded string is stored
//
// Example:
//
//&nbsp;&nbsp; &nbsp;&nbsp;&nbsp; &nbsp;b64_encode_string( "Encode Me!", "b64" )
// ----------------------------------------------------------------------------
{
 int dest_size;
 int res;
 char *dest;
 // Allocate dest buffer
 dest_size = 1 + ((strlen(source)+2)/3*4);
 dest = (char *)malloc(dest_size);
 memset(dest,0,dest_size);
 // Encode & Save
 base64encode(source, dest, dest_size);
 lr_save_string( dest, lrvar );
 // Free dest buffer
 res = strlen(dest);
 free(dest);
 // Return length of dest string
 return res;
}

int b64_decode_string( char *source, char *lrvar )
// ----------------------------------------------------------------------------
// Decodes a base64 string to plaintext
//
// Parameters:
//&nbsp;&nbsp; &nbsp;&nbsp;&nbsp; &nbsp;source&nbsp;&nbsp;&nbsp; Pointer to source base64 encoded string
//&nbsp;&nbsp; &nbsp;&nbsp;&nbsp; &nbsp;lrvar&nbsp;&nbsp;&nbsp;&nbsp; LR variable where decoded string is stored
//
// Example:
//
//&nbsp;&nbsp; &nbsp;&nbsp;&nbsp; &nbsp;b64_decode_string( lr_eval_string("{b64}"), "Plain" )
// ----------------------------------------------------------------------------
{
 int dest_size;
 int res;
 char *dest;
 // Allocate dest buffer
 dest_size = strlen(source);
 dest = (char *)malloc(dest_size);
 memset(dest,0,dest_size);
 // Encode & Save
 base64decode(source, dest, dest_size);
 lr_save_string( dest, lrvar );
 // Free dest buffer
 res = strlen(dest);
 free(dest);
 // Return length of dest string
 return res;
}

使用的例子如下所示：

#include "base64.h"

vuser_init()
{
 int res; 

 // ENCODE  
 lr_save_string("ABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789","plain");  
 b64_encode_string( lr_eval_string("{plain}"), "b64str" );  
 lr_output_message("Encoded: %s", lr_eval_string("{b64str}") ); 

 // DECODE  
 b64_decode_string( lr_eval_string("{b64str}"), "plain2" );  
 lr_output_message("Decoded: %s", lr_eval_string("{plain2}") );  
   
 // Verify decoded matches original plain text  
 res = strcmp( lr_eval_string("{plain}"), lr_eval_string("{plain2}") );  
 if (res==0) lr_output_message("Decoded matches original plain text");  
 
 return 0; 

}