kicad/common/base64.cpp

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/*
* This program source code file is part of KiCad, a free EDA CAD application.
*
* Copyright (C) 2019 KiCad Developers, see AUTHORS.txt for contributors.
*
* @author Seth Hillbrand <seth@kipro-pcb.com>
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version 3
* of the License, or (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License along
* with this program. If not, see <http://www.gnu.org/licenses/>.
*/
#include <base64.h>
#include <cstdint>
#include <cstddef>
#include <limits>
#include <vector>
namespace {
static const uint8_t ENCODE_BASE64[64] = {
0x41, 0x42, 0x43, 0x44, 0x45, 0x46, 0x47, 0x48,
0x49, 0x4A, 0x4B, 0x4C, 0x4D, 0x4E, 0x4F, 0x50,
0x51, 0x52, 0x53, 0x54, 0x55, 0x56, 0x57, 0x58,
0x59, 0x5A, 0x61, 0x62, 0x63, 0x64, 0x65, 0x66,
0x67, 0x68, 0x69, 0x6A, 0x6B, 0x6C, 0x6D, 0x6E,
0x6F, 0x70, 0x71, 0x72, 0x73, 0x74, 0x75, 0x76,
0x77, 0x78, 0x79, 0x7A, 0x30, 0x31, 0x32, 0x33,
0x34, 0x35, 0x36, 0x37, 0x38, 0x39, 0x2B, 0x2F,
};
static const uint8_t E = -1;
static const uint8_t DECODE_BASE64[128] = {
/* 0x0 0x1 0x2 0x3 0x4 0x5 0x6 0x7 0x8 0x9 0xA 0xB 0xC 0xD 0xE 0xF */
E, E, E, E, E, E, E, E, E, E, E, E, E, E, E, E,
E, E, E, E, E, E, E, E, E, E, E, E, E, E, E, E,
E, E, E, E, E, E, E, E, E, E, E, 62, E, E, E, 63,
52, 53, 54, 55, 56, 57, 58, 59, 60, 61, E, E, E, E, E, E,
E, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14,
15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, E, E, E, E, E,
E, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40,
41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, E, E, E, E, E,
};
} // namespace
namespace base64
{
size_t encode_length( size_t aInputLen )
{
return 4 * ( ( aInputLen + 2 ) / 3 ) + ( aInputLen + 2 ) % 3 - 2;
}
size_t decode_length( size_t aInputLen )
{
if( aInputLen % 4 == 1 )
return 0;
else
return 3 * ( ( aInputLen + 2 ) / 4 ) + ( aInputLen + 2 ) % 4 - 2;
}
void encode( const std::vector<uint8_t>& aInput, std::vector<uint8_t>& aOutput )
{
size_t end = ( aInput.size() / 3 ) * 3;
aOutput.reserve( encode_length( aInput.size() ) );
for( size_t i = 0; i < end; i += 3 )
{
unsigned value = ( aInput[i] << 16 ) | ( aInput[i + 1] << 8 ) | aInput[i + 2] ;
aOutput.emplace_back( ENCODE_BASE64[( value >> 18 ) & 0x3F] );
aOutput.emplace_back( ENCODE_BASE64[( value >> 12 ) & 0x3F] );
aOutput.emplace_back( ENCODE_BASE64[( value >> 6 ) & 0x3F] );
aOutput.emplace_back( ENCODE_BASE64[value & 0x3F] );
}
size_t remainder = aInput.size() - end;
if( remainder )
{
unsigned value = aInput[end];
if( remainder == 2 )
{
value = ( value << 10 ) | ( aInput[end + 1] << 2 );
aOutput.emplace_back( ENCODE_BASE64[( value >> 12 ) & 0x3F] );
}
else
{
value <<= 4;
}
aOutput.emplace_back( ENCODE_BASE64[( value >> 6 ) & 0x3F] );
aOutput.emplace_back( ENCODE_BASE64[value & 0x3F] );
}
}
void decode(const std::vector<uint8_t>& aInput, std::vector<uint8_t>& aOutput )
{
size_t end = ( aInput.size() / 4 ) * 4;
size_t decode_size = decode_length( aInput.size() );
if( !decode_size )
return;
aOutput.reserve( decode_size );
for( size_t i = 0; i < end; i++ )
{
unsigned value = ( DECODE_BASE64[aInput[i] & 0x7F] << 18 ) |
( DECODE_BASE64[aInput[i + 1] & 0x7F] << 12 ) |
( DECODE_BASE64[aInput[i + 2] & 0x7F] << 6 ) |
DECODE_BASE64[aInput[i + 3] & 0x7F];
aOutput.emplace_back( ( value >> 16 ) & 0xff );
aOutput.emplace_back( ( value >> 8 ) & 0xff );
aOutput.emplace_back( value & 0xff );
}
size_t remainder = aInput.size() - end;
if( remainder )
{
unsigned value = ( ( DECODE_BASE64[aInput[end] & 0x7F] ) << 6 ) |
( DECODE_BASE64[aInput[end + 1] & 0x7F] );
if( remainder == 3 )
{
value = ( value << 6 ) | ( DECODE_BASE64[aInput[end + 2] & 0x7F] );
value >>= 2;
aOutput.emplace_back( ( value >> 8 ) & 0xff );
}
else
{
value >>= 4;
}
aOutput[0] = value & 0xff ;
}
}
} // base64