293 lines
8.3 KiB
C
293 lines
8.3 KiB
C
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/***************************************************************************
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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) 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 https://curl.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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* SPDX-License-Identifier: curl
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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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#if !defined(CURL_DISABLE_HTTP_AUTH) || defined(USE_SSH) || \
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!defined(CURL_DISABLE_LDAP) || \
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!defined(CURL_DISABLE_SMTP) || \
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!defined(CURL_DISABLE_POP3) || \
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!defined(CURL_DISABLE_IMAP) || \
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!defined(CURL_DISABLE_DOH) || defined(USE_SSL)
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#include "curl/curl.h"
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#include "warnless.h"
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#include "curl_base64.h"
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/* The last 2 #include files should be in this order */
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#ifdef BUILDING_LIBCURL
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#include "curl_memory.h"
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#endif
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#include "memdebug.h"
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/* ---- Base64 Encoding/Decoding Table --- */
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/* Padding character string starts at offset 64. */
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static const char base64encdec[]=
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"ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/=";
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/* The Base 64 encoding with a URL and filename safe alphabet, RFC 4648
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section 5 */
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static const char base64url[]=
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"ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789-_";
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static const unsigned char decodetable[] =
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{ 62, 255, 255, 255, 63, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 255, 255, 255,
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255, 255, 255, 255, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16,
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17, 18, 19, 20, 21, 22, 23, 24, 25, 255, 255, 255, 255, 255, 255, 26, 27, 28,
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29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47,
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48, 49, 50, 51 };
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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 padding = 0;
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size_t i;
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size_t numQuantums;
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size_t fullQuantums;
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size_t rawlen = 0;
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unsigned char *pos;
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unsigned char *newstr;
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unsigned char lookup[256];
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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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/* srclen is at least 4 here */
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while(src[srclen - 1 - padding] == '=') {
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/* count padding characters */
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padding++;
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/* A maximum of two = padding characters is allowed */
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if(padding > 2)
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return CURLE_BAD_CONTENT_ENCODING;
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}
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/* Calculate the number of quantums */
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numQuantums = srclen / 4;
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fullQuantums = numQuantums - (padding ? 1 : 0);
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/* Calculate the size of the decoded string */
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rawlen = (numQuantums * 3) - padding;
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/* Allocate our buffer including room for a null-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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pos = newstr;
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memset(lookup, 0xff, sizeof(lookup));
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memcpy(&lookup['+'], decodetable, sizeof(decodetable));
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/* replaces
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{
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unsigned char c;
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const unsigned char *p = (const unsigned char *)base64encdec;
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for(c = 0; *p; c++, p++)
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lookup[*p] = c;
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}
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*/
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/* Decode the complete quantums first */
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for(i = 0; i < fullQuantums; i++) {
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unsigned char val;
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unsigned int x = 0;
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int j;
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for(j = 0; j < 4; j++) {
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val = lookup[(unsigned char)*src++];
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if(val == 0xff) /* bad symbol */
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goto bad;
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x = (x << 6) | val;
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}
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pos[2] = x & 0xff;
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pos[1] = (x >> 8) & 0xff;
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pos[0] = (x >> 16) & 0xff;
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pos += 3;
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}
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if(padding) {
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/* this means either 8 or 16 bits output */
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unsigned char val;
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unsigned int x = 0;
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int j;
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size_t padc = 0;
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for(j = 0; j < 4; j++) {
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if(*src == '=') {
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x <<= 6;
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src++;
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if(++padc > padding)
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/* this is a badly placed '=' symbol! */
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goto bad;
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}
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else {
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val = lookup[(unsigned char)*src++];
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if(val == 0xff) /* bad symbol */
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goto bad;
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x = (x << 6) | val;
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}
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}
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if(padding == 1)
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pos[1] = (x >> 8) & 0xff;
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pos[0] = (x >> 16) & 0xff;
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pos += 3 - padding;
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}
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/* Zero terminate */
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*pos = '\0';
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/* Return the decoded data */
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*outptr = newstr;
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*outlen = rawlen;
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return CURLE_OK;
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bad:
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free(newstr);
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return CURLE_BAD_CONTENT_ENCODING;
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}
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static CURLcode base64_encode(const char *table64,
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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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char *output;
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char *base64data;
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const unsigned char *in = (unsigned char *)inputbuff;
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const char *padstr = &table64[64]; /* Point to padding string. */
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*outptr = NULL;
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*outlen = 0;
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if(!insize)
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insize = strlen(inputbuff);
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#if SIZEOF_SIZE_T == 4
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if(insize > UINT_MAX/4)
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return CURLE_OUT_OF_MEMORY;
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#endif
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base64data = output = malloc((insize + 2) / 3 * 4 + 1);
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if(!output)
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return CURLE_OUT_OF_MEMORY;
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while(insize >= 3) {
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*output++ = table64[ in[0] >> 2 ];
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*output++ = table64[ ((in[0] & 0x03) << 4) | (in[1] >> 4) ];
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*output++ = table64[ ((in[1] & 0x0F) << 2) | ((in[2] & 0xC0) >> 6) ];
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*output++ = table64[ in[2] & 0x3F ];
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insize -= 3;
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in += 3;
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}
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if(insize) {
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/* this is only one or two bytes now */
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*output++ = table64[ in[0] >> 2 ];
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if(insize == 1) {
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*output++ = table64[ ((in[0] & 0x03) << 4) ];
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if(*padstr) {
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*output++ = *padstr;
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*output++ = *padstr;
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}
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}
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else {
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/* insize == 2 */
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*output++ = table64[ ((in[0] & 0x03) << 4) | ((in[1] & 0xF0) >> 4) ];
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*output++ = table64[ ((in[1] & 0x0F) << 2) ];
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if(*padstr)
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*output++ = *padstr;
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}
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}
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/* Zero terminate */
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*output = '\0';
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/* Return the pointer to the new data (allocated memory) */
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*outptr = base64data;
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/* Return the length of the new data */
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*outlen = output - base64data;
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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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* @unittest: 1302
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*/
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CURLcode Curl_base64_encode(const char *inputbuff, size_t insize,
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char **outptr, size_t *outlen)
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{
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return base64_encode(base64encdec, inputbuff, insize, outptr, outlen);
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}
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/*
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* Curl_base64url_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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* @unittest: 1302
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*/
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CURLcode Curl_base64url_encode(const char *inputbuff, size_t insize,
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char **outptr, size_t *outlen)
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{
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return base64_encode(base64url, inputbuff, insize, outptr, outlen);
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}
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#endif /* no users so disabled */
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