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curl/lib/base64.c

271 lines
6.8 KiB
C

/*****************************************************************************
* _ _ ____ _
* Project ___| | | | _ \| |
* / __| | | | |_) | |
* | (__| |_| | _ <| |___
* \___|\___/|_| \_\_____|
*
* Copyright (C) 2001, Andrew Francis and Daniel Stenberg
*
* In order to be useful for every potential user, curl and libcurl are
* dual-licensed under the MPL and the MIT/X-derivate licenses.
*
* 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 MPL or the MIT/X-derivate
* licenses. You may pick one of these licenses.
*
* 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 "base64.h"
#ifdef MALLOCDEBUG
#include "memdebug.h"
#endif
static void decodeQuantum(unsigned char *dest, char *src)
{
unsigned int x = 0;
int i;
for(i = 0; i < 4; i++) {
if(src[i] >= 'A' && src[i] <= 'Z')
x = (x << 6) + (unsigned int)(src[i] - 'A' + 0);
else if(src[i] >= 'a' && src[i] <= 'z')
x = (x << 6) + (unsigned int)(src[i] - 'a' + 26);
else if(src[i] >= '0' && src[i] <= '9')
x = (x << 6) + (unsigned int)(src[i] - '0' + 52);
else if(src[i] == '+')
x = (x << 6) + 62;
else if(src[i] == '/')
x = (x << 6) + 63;
}
dest[2] = (unsigned char)(x & 255); x >>= 8;
dest[1] = (unsigned char)(x & 255); x >>= 8;
dest[0] = (unsigned char)(x & 255); x >>= 8;
}
/* base64Decode
* Given a base64 string at src, decode it into the memory pointed
* to by dest. If rawLength points to a valid address (ie not NULL),
* store the length of the decoded data to it.
*/
static void base64Decode(unsigned char *dest, char *src, int *rawLength)
{
int length = 0;
int equalsTerm = 0;
int i;
unsigned char lastQuantum[3];
while((src[length] != '=') && src[length])
length++;
while(src[length+equalsTerm] == '=')
equalsTerm++;
if(rawLength)
*rawLength = (length * 3 / 4) - equalsTerm;
for(i = 0; i < length/4 - 1; i++) {
decodeQuantum(dest, src);
dest += 3; src += 4;
}
decodeQuantum(lastQuantum, src);
for(i = 0; i < 3 - equalsTerm; i++) dest[i] = lastQuantum[i];
}
/* ---- Base64 Encoding --- */
static char table64[]=
"ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
/*
* 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, -1 is returned.
*
*/
int Curl_base64_encode(const void *inp, int insize, char **outptr)
{
unsigned char ibuf[3];
unsigned char obuf[4];
int i;
int inputparts;
char *output;
char *base64data;
char *indata = (char *)inp;
if(0 == insize)
insize = strlen(indata);
base64data = output = (char*)malloc(insize*4/3+4);
if(NULL == output)
return -1;
while(insize > 0) {
for (i = inputparts = 0; i < 3; i++) {
if(*indata) {
inputparts++;
ibuf[i] = *indata;
indata++;
insize--;
}
else
ibuf[i] = 0;
}
obuf [0] = (ibuf [0] & 0xFC) >> 2;
obuf [1] = ((ibuf [0] & 0x03) << 4) | ((ibuf [1] & 0xF0) >> 4);
obuf [2] = ((ibuf [1] & 0x0F) << 2) | ((ibuf [2] & 0xC0) >> 6);
obuf [3] = ibuf [2] & 0x3F;
switch(inputparts) {
case 1: /* only one byte read */
sprintf(output, "%c%c==",
table64[obuf[0]],
table64[obuf[1]]);
break;
case 2: /* two bytes read */
sprintf(output, "%c%c%c=",
table64[obuf[0]],
table64[obuf[1]],
table64[obuf[2]]);
break;
default:
sprintf(output, "%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 */
return strlen(base64data); /* return the length of the new data */
}
/* ---- End of Base64 Encoding ---- */
int Curl_base64_decode(const char *str, void *data)
{
int ret;
base64Decode((unsigned char *)data, (char *)str, &ret);
return ret;
}
/************* TEST HARNESS STUFF ****************/
#ifdef TEST_ENCODE
/* encoding test harness. Read in standard input and write out the length
* returned by Curl_base64_encode, followed by the base64'd data itself
*/
#include <stdio.h>
#define TEST_NEED_SUCK
void *suck(int *);
int main(int argc, char **argv, char **envp) {
char *base64;
int base64Len;
unsigned char *data;
int dataLen;
data = (unsigned char *)suck(&dataLen);
base64Len = Curl_base64_encode(data, dataLen, &base64);
fprintf(stderr, "%d\n", base64Len);
fprintf(stdout, "%s", base64);
free(base64); free(data);
return 0;
}
#endif
#ifdef TEST_DECODE
/* decoding test harness. Read in a base64 string from stdin and write out the
* length returned by Curl_base64_decode, followed by the decoded data itself
*/
#include <stdio.h>
#define TEST_NEED_SUCK
void *suck(int *);
int main(int argc, char **argv, char **envp) {
char *base64;
int base64Len;
unsigned char *data;
int dataLen;
base64 = (char *)suck(&base64Len);
data = (unsigned char *)malloc(base64Len * 3/4 + 8);
dataLen = Curl_base64_decode(base64, data);
fprintf(stderr, "%d\n", dataLen);
fwrite(data,1,dataLen,stdout);
free(base64); free(data);
return 0;
}
#endif
#ifdef TEST_NEED_SUCK
/* this function 'sucks' in as much as possible from stdin */
void *suck(int *lenptr) {
int cursize = 8192;
unsigned char *buf = NULL;
int lastread;
int len = 0;
do {
cursize *= 2;
buf = (unsigned char *)realloc(buf, cursize);
memset(buf + len, 0, cursize - len);
lastread = fread(buf + len, 1, cursize - len, stdin);
len += lastread;
} while(!feof(stdin));
lenptr[0] = len;
return (void *)buf;
}
#endif
/*
* local variables:
* eval: (load-file "../curl-mode.el")
* end:
* vim600: fdm=marker
* vim: et sw=2 ts=2 sts=2 tw=78
*/