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/***************************************************************************
* _ _ ____ _
* Project ___| | | | _ \| |
* / __| | | | |_) | |
* | (__| |_| | _ <| |___
* \___|\___/|_| \_\_____|
*
* Copyright (C) 1998 - 2009, Daniel Stenberg, <daniel@haxx.se>, et al.
*
* This software is licensed as described in the file COPYING, which
* you should have received as part of this distribution. The terms
* are also available at http://curl.haxx.se/docs/copyright.html.
*
* You may opt to use, copy, modify, merge, publish, distribute and/or sell
* copies of the Software, and permit persons to whom the Software is
* furnished to do so, under the terms of the COPYING file.
*
* This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
* KIND, either express or implied.
*
* $Id$
***************************************************************************/
/* Base64 encoding/decoding
*
* Test harnesses down the bottom - compile with -DTEST_ENCODE for
* a program that will read in raw data from stdin and write out
* a base64-encoded version to stdout, and the length returned by the
* encoding function to stderr. Compile with -DTEST_DECODE for a program that
* will go the other way.
*
* This code will break if int is smaller than 32 bits
*/
#include "setup.h"
#include <stdlib.h>
#include <string.h>
#define _MPRINTF_REPLACE /* use our functions only */
#include <curl/mprintf.h>
#include "urldata.h" /* for the SessionHandle definition */
#include "easyif.h" /* for Curl_convert_... prototypes */
#include "curl_base64.h"
#include "curl_memory.h"
/* include memdebug.h last */
#include "memdebug.h"
/* ---- Base64 Encoding/Decoding Table --- */
static const char table64[]=
"ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
static void decodeQuantum(unsigned char *dest, const char *src)
{
unsigned int x = 0;
int i;
char *found;
for(i = 0; i < 4; i++) {
if((found = strchr(table64, src[i])) != NULL)
x = (x << 6) + (unsigned int)(found - table64);
else if(src[i] == '=')
x = (x << 6);
}
dest[2] = (unsigned char)(x & 255);
x >>= 8;
dest[1] = (unsigned char)(x & 255);
x >>= 8;
dest[0] = (unsigned char)(x & 255);
}
/*
* Curl_base64_decode()
*
* Given a base64 string at src, decode it and return an allocated memory in
* the *outptr. Returns the length of the decoded data.
*/
size_t Curl_base64_decode(const char *src, unsigned char **outptr)
{
int length = 0;
int equalsTerm = 0;
int i;
int numQuantums;
unsigned char lastQuantum[3];
size_t rawlen=0;
unsigned char *newstr;
*outptr = NULL;
while((src[length] != '=') && src[length])
length++;
/* A maximum of two = padding characters is allowed */
if(src[length] == '=') {
equalsTerm++;
if(src[length+equalsTerm] == '=')
equalsTerm++;
}
numQuantums = (length + equalsTerm) / 4;
/* Don't allocate a buffer if the decoded length is 0 */
if(numQuantums <= 0)
return 0;
rawlen = (numQuantums * 3) - equalsTerm;
/* The buffer must be large enough to make room for the last quantum
(which may be partially thrown out) and the zero terminator. */
newstr = malloc(rawlen+4);
if(!newstr)
return 0;
*outptr = newstr;
/* Decode all but the last quantum (which may not decode to a
multiple of 3 bytes) */
for(i = 0; i < numQuantums - 1; i++) {
decodeQuantum(newstr, src);
newstr += 3; src += 4;
}
/* This final decode may actually read slightly past the end of the buffer
if the input string is missing pad bytes. This will almost always be
harmless. */
decodeQuantum(lastQuantum, src);
for(i = 0; i < 3 - equalsTerm; i++)
newstr[i] = lastQuantum[i];
newstr[i] = 0; /* zero terminate */
return rawlen;
}
/*
* Curl_base64_encode()
*
* Returns the length of the newly created base64 string. The third argument
* is a pointer to an allocated area holding the base64 data. If something
* went wrong, 0 is returned.
*
*/
size_t Curl_base64_encode(struct SessionHandle *data,
const char *inputbuff, size_t insize,
char **outptr)
{
unsigned char ibuf[3];
unsigned char obuf[4];
int i;
int inputparts;
char *output;
char *base64data;
#ifdef CURL_DOES_CONVERSIONS
char *convbuf = NULL;
#endif
const char *indata = inputbuff;
*outptr = NULL; /* set to NULL in case of failure before we reach the end */
if(0 == insize)
insize = strlen(indata);
base64data = output = malloc(insize*4/3+4);
if(NULL == output)
return 0;
#ifdef CURL_DOES_CONVERSIONS
/*
* The base64 data needs to be created using the network encoding
* not the host encoding. And we can't change the actual input
* so we copy it to a buffer, translate it, and use that instead.
*/
if(data) {
convbuf = malloc(insize);
if(!convbuf) {
free(output);
return 0;
}
memcpy(convbuf, indata, insize);
if(CURLE_OK != Curl_convert_to_network(data, convbuf, insize)) {
free(convbuf);
free(output);
return 0;
}
indata = convbuf; /* switch to the converted buffer */
}
#else
(void)data;
#endif
while(insize > 0) {
for (i = inputparts = 0; i < 3; i++) {
if(insize > 0) {
inputparts++;
ibuf[i] = *indata;
indata++;
insize--;
}
else
ibuf[i] = 0;
}
obuf[0] = (unsigned char) ((ibuf[0] & 0xFC) >> 2);
obuf[1] = (unsigned char) (((ibuf[0] & 0x03) << 4) | \
((ibuf[1] & 0xF0) >> 4));
obuf[2] = (unsigned char) (((ibuf[1] & 0x0F) << 2) | \
((ibuf[2] & 0xC0) >> 6));
obuf[3] = (unsigned char) (ibuf[2] & 0x3F);
switch(inputparts) {
case 1: /* only one byte read */
snprintf(output, 5, "%c%c==",
table64[obuf[0]],
table64[obuf[1]]);
break;
case 2: /* two bytes read */
snprintf(output, 5, "%c%c%c=",
table64[obuf[0]],
table64[obuf[1]],
table64[obuf[2]]);
break;
default:
snprintf(output, 5, "%c%c%c%c",
table64[obuf[0]],
table64[obuf[1]],
table64[obuf[2]],
table64[obuf[3]] );
break;
}
output += 4;
}
*output=0;
*outptr = base64data; /* make it return the actual data memory */
#ifdef CURL_DOES_CONVERSIONS
if(data)
free(convbuf);
#endif
return strlen(base64data); /* return the length of the new data */
}
/* ---- End of Base64 Encoding ---- */
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