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