apps/codecs/libgme/rom_data.c

   1 // Game_Music_Emu 0.5.2. http://www.slack.net/~ant/
   2
   3 #include "rom_data.h"
   4
   5 /* Copyright (C) 2003-2006 Shay Green. This module is free software; you
   6 can redistribute it and/or modify it under the terms of the GNU Lesser
   7 General Public License as published by the Free Software Foundation; either
   8 version 2.1 of the License, or (at your option) any later version. This
   9 module is distributed in the hope that it will be useful, but WITHOUT ANY
  10 WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
  11 FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more
  12 details. You should have received a copy of the GNU Lesser General Public
  13 License along with this module; if not, write to the Free Software Foundation,
  14 Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA */
  15
  16 #include <string.h>
  17 #include "blargg_source.h"
  18
  19 // Rom_Data
  20
  21 blargg_err_t Rom_load( struct Rom_Data* this, const void* data, long size,
  22                 int header_size, void* header_out, int fill )
  23 {
  24         long file_offset = this->pad_size;
  25
  26         this->rom_addr = 0;
  27         this->mask     = 0;
  28         this->size    = 0;
  29
  30         if ( size <= header_size ) // <= because there must be data after header
  31                 return gme_wrong_file_type;
  32
  33         // Read header
  34         memcpy( header_out, data, header_size );
  35
  36         this->file_size = size - header_size;
  37         this->file_data = (byte*) data + header_size;
  38
  39         memset( this->unmapped, fill, this->rom_size );
  40         memcpy( &this->unmapped [file_offset], this->file_data,
  41                 this->file_size < this->pad_size ? this->file_size : this->pad_size );
  42
  43         return 0;
  44 }
  45
  46 void Rom_set_addr( struct Rom_Data* this, long addr )
  47 {
  48         this->rom_addr = addr - this->bank_size - pad_extra;
  49
  50         long rounded = (addr + this->file_size + this->bank_size - 1) / this->bank_size * this->bank_size;
  51         if ( rounded <= 0 )
  52         {
  53                 rounded = 0;
  54         }
  55         else
  56         {
  57                 int shift = 0;
  58                 unsigned long max_addr = (unsigned long) (rounded - 1);
  59                 while ( max_addr >> shift )
  60                         shift++;
  61                 this->mask = (1L << shift) - 1;
  62         }
  63
  64         if ( addr < 0 )
  65                 addr = 0;
  66         this->size = rounded;
  67         this->rsize_ = rounded - this->rom_addr + pad_extra;
  68 }