100 lines
2.8 KiB
C++
100 lines
2.8 KiB
C++
// Game_Music_Emu $vers. http://www.slack.net/~ant/
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#include "Rom_Data.h"
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/* Copyright (C) 2003-2009 Shay Green. This module is free software; you
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can redistribute it and/or modify it under the terms of the GNU Lesser
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General Public License as published by the Free Software Foundation; either
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version 2.1 of the License, or (at your option) any later version. This
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module is distributed in the hope that it will be useful, but WITHOUT ANY
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WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
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FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more
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details. You should have received a copy of the GNU Lesser General Public
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License along with this module; if not, write to the Free Software Foundation,
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Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA */
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#include "blargg_source.h"
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void Rom_Data::clear()
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{
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file_size_ = 0;
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rom_addr = 0;
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mask = 0;
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rom.clear();
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}
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Rom_Data::Rom_Data( int page_size ) :
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pad_size( page_size + pad_extra )
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{
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// page_size should be power of 2
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check( (page_size & (page_size - 1)) == 0 );
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clear();
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}
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Rom_Data::~Rom_Data()
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{ }
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// Reads file into array, placing file_offset bytes of padding before the beginning, and pad_size after the end
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blargg_err_t Rom_Data::load_( Data_Reader& in, int header_size, int file_offset )
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{
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clear();
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file_size_ = in.remain();
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if ( file_size_ <= header_size ) // <= because there must be data after header
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return blargg_err_file_type;
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RETURN_ERR( rom.resize( file_offset + file_size_ + pad_size ) );
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return in.read( rom.begin() + file_offset, file_size_ );
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}
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blargg_err_t Rom_Data::load( Data_Reader& in, int header_size,
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void* header_out, int fill )
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{
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int file_offset = pad_size - header_size;
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blargg_err_t err = load_( in, header_size, file_offset );
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if ( err )
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{
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clear();
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return err;
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}
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file_size_ -= header_size;
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memcpy( header_out, &rom [file_offset], header_size );
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memset( rom.begin() , fill, pad_size );
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memset( rom.end() - pad_size, fill, pad_size );
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return blargg_ok;
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}
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void Rom_Data::set_addr( int addr )
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{
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int const page_size = pad_size - pad_extra;
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// Minimum size that contains all bytes and is a multiple of page_size
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int const size = (addr + file_size_ + page_size - 1) / page_size * page_size;
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// Find lowest power of 2 that is >= size
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int power2 = 1;
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while ( power2 < size )
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power2 *= 2;
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mask = power2 - 1;
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// Address of first byte of ROM (possibly negative)
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rom_addr = addr - page_size - pad_extra;
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if ( rom.resize( size - rom_addr + pad_extra ) ) { } // OK if shrink fails
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}
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byte* Rom_Data::at_addr( int addr )
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{
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int offset = mask_addr( addr ) - rom_addr;
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if ( (unsigned) offset > (unsigned) (rom.size() - pad_size) )
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offset = 0; // unmapped
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return &rom [offset];
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}
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