137 lines
4.8 KiB
C
137 lines
4.8 KiB
C
/*
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* Harbour Project source code:
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* hb_base64Decode() function
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*
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* Copyright 2011 Viktor Szakats (vszakats.net/harbour)
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* [ base64_decode_* functions are part of the libb64 project, and has
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* been placed in the public domain. Author: Chris Venter
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* For details, see http://sourceforge.net/projects/libb64 ]
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* www - http://harbour-project.org
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2, or (at your option)
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* any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this software; see the file COPYING.txt. If not, write to
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* the Free Software Foundation, Inc., 59 Temple Place, Suite 330,
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* Boston, MA 02111-1307 USA (or visit the web site http://www.gnu.org/).
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*
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* As a special exception, the Harbour Project gives permission for
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* additional uses of the text contained in its release of Harbour.
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*
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* The exception is that, if you link the Harbour libraries with other
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* files to produce an executable, this does not by itself cause the
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* resulting executable to be covered by the GNU General Public License.
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* Your use of that executable is in no way restricted on account of
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* linking the Harbour library code into it.
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*
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* This exception does not however invalidate any other reasons why
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* the executable file might be covered by the GNU General Public License.
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*
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* This exception applies only to the code released by the Harbour
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* Project under the name Harbour. If you copy code from other
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* Harbour Project or Free Software Foundation releases into a copy of
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* Harbour, as the General Public License permits, the exception does
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* not apply to the code that you add in this way. To avoid misleading
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* anyone as to the status of such modified files, you must delete
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* this exception notice from them.
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*
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* If you write modifications of your own for Harbour, it is your choice
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* whether to permit this exception to apply to your modifications.
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* If you do not wish that, delete this exception notice.
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*
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*/
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#include "hbapi.h"
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/* Warning: this code works only on ASCII based machines */
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static signed char base64_decode_value( int value_in )
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{
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static const signed char s_decoding[] =
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{
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62, -1, -1, -1, 63, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, -1, -1, -1, -2, -1,
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-1, -1, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17,
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18, 19, 20, 21, 22, 23, 24, 25, -1, -1, -1, -1, -1, -1, 26, 27, 28, 29, 30, 31,
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32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51
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};
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value_in -= 43;
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if( value_in < 0 || value_in >= ( int ) HB_SIZEOFARRAY( s_decoding ) )
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return -1;
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return s_decoding[ value_in ];
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}
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static HB_SIZE base64_decode_block( const char * code_in, const HB_SIZE length_in, char * pszPlainttextOut )
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{
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const char * codechar = code_in;
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const char * code_end = code_in + length_in;
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char * pszPlainchar = pszPlainttextOut;
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signed char fragment;
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for(;; )
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{
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do
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{
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if( codechar == code_end )
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return pszPlainchar - pszPlainttextOut;
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fragment = base64_decode_value( *codechar++ );
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}
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while( fragment < 0 );
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*pszPlainchar = ( fragment & 0x03F ) << 2;
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do
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{
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if( codechar == code_end )
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return pszPlainchar - pszPlainttextOut;
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fragment = base64_decode_value( *codechar++ );
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}
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while( fragment < 0 );
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*pszPlainchar++ |= ( fragment & 0x030 ) >> 4;
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*pszPlainchar = ( fragment & 0x00F ) << 4;
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do
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{
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if( codechar == code_end )
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return pszPlainchar - pszPlainttextOut;
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fragment = base64_decode_value( *codechar++ );
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}
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while( fragment < 0 );
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*pszPlainchar++ |= ( fragment & 0x03C ) >> 2;
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*pszPlainchar = ( fragment & 0x003 ) << 6;
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do
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{
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if( codechar == code_end )
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return pszPlainchar - pszPlainttextOut;
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fragment = base64_decode_value( *codechar++ );
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}
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while( fragment < 0 );
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*pszPlainchar++ |= ( fragment & 0x03F );
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}
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}
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HB_FUNC( HB_BASE64DECODE )
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{
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HB_SIZE nSrcLen = hb_parclen( 1 );
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if( nSrcLen > 0 )
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{
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HB_SIZE nDstLen = ( ( ( nSrcLen * 3 ) / 4 ) + 1 ) * sizeof( char );
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char * code = ( char * ) hb_xgrab( nDstLen );
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nDstLen = base64_decode_block( hb_parcx( 1 ), nSrcLen, code );
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hb_retclen_buffer( code, nDstLen );
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}
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else
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hb_retc_null();
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}
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