mirror of
https://github.com/curl/curl.git
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4d10f48629
Due to the length checks introduced in commit e17c1b25bc there is no
need to allow for extra space in the output buffer for a non-padded last
quantum.
259 lines
6.9 KiB
C
259 lines
6.9 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 - 2013, 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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#include "curl_setup.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 "warnless.h"
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#include "curl_base64.h"
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#include "curl_memory.h"
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#include "non-ascii.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 & 0xFFUL);
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x >>= 8;
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dest[1] = curlx_ultouc(x & 0xFFUL);
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x >>= 8;
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dest[0] = curlx_ultouc(x & 0xFFUL);
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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 NUL-terminated string at src, decode it and return a
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* pointer in *outptr to a newly allocated memory area holding decoded
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* data. Size of decoded data is returned in variable pointed by outlen.
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*
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* Returns CURLE_OK on success, otherwise specific error code. Function
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* output shall not be considered valid unless CURLE_OK is returned.
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*
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* When decoded data length is 0, returns NULL in *outptr.
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*
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* @unittest: 1302
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*/
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CURLcode Curl_base64_decode(const char *src,
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unsigned char **outptr, size_t *outlen)
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{
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size_t srcLen = 0;
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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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*outlen = 0;
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srcLen = strlen(src);
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/* Check the length of the input string is valid */
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if(!srcLen || srcLen % 4)
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return CURLE_BAD_CONTENT_ENCODING;
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/* Find the position of any = padding characters */
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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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/* Check the = padding characters weren't part way through the input */
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if(length + equalsTerm != srcLen)
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return CURLE_BAD_CONTENT_ENCODING;
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/* Calculate the number of quantums */
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numQuantums = srcLen / 4;
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/* Calculate the size of the decoded string */
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rawlen = (numQuantums * 3) - equalsTerm;
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/* Allocate our buffer including room for a zero terminator */
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newstr = malloc(rawlen + 1);
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if(!newstr)
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return CURLE_OUT_OF_MEMORY;
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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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/* Decode the last quantum */
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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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/* Zero terminate */
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newstr[i] = '\0';
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/* Return the size of decoded data */
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*outlen = rawlen;
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return CURLE_OK;
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}
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/*
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* Curl_base64_encode()
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*
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* Given a pointer to an input buffer and an input size, encode it and
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* return a pointer in *outptr to a newly allocated memory area holding
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* encoded data. Size of encoded data is returned in variable pointed by
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* outlen.
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*
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* Input length of 0 indicates input buffer holds a NUL-terminated string.
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*
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* Returns CURLE_OK on success, otherwise specific error code. Function
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* output shall not be considered valid unless CURLE_OK is returned.
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*
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* When encoded data length is 0, returns NULL in *outptr.
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*
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* @unittest: 1302
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*/
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CURLcode Curl_base64_encode(struct SessionHandle *data,
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const char *inputbuff, size_t insize,
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char **outptr, size_t *outlen)
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{
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CURLcode error;
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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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char *convbuf = NULL;
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const char *indata = inputbuff;
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*outptr = NULL;
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*outlen = 0;
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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 CURLE_OUT_OF_MEMORY;
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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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error = Curl_convert_clone(data, indata, insize, &convbuf);
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if(error) {
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free(output);
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return error;
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}
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if(convbuf)
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indata = (char *)convbuf;
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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; /* return pointer to new data, allocated memory */
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if(convbuf)
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free(convbuf);
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*outlen = strlen(base64data); /* return the length of the new data */
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return CURLE_OK;
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}
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/* ---- End of Base64 Encoding ---- */
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