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Spc_Emu.cpp
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Spc_Emu.cpp
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// Game_Music_Emu 0.5.5. http://www.slack.net/~ant/
#include "Spc_Emu.h"
#include "blargg_endian.h"
#include <stdlib.h>
#include <string.h>
/* Copyright (C) 2004-2006 Shay Green. This module is free software; you
can redistribute it and/or modify it under the terms of the GNU Lesser
General Public License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version. This
module 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 Lesser General Public License for more
details. You should have received a copy of the GNU Lesser General Public
License along with this module; if not, write to the Free Software Foundation,
Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA */
#include "blargg_source.h"
Spc_Emu::Spc_Emu()
{
set_type( gme_spc_type );
static const char* const names [Snes_Spc::voice_count] = {
"DSP 1", "DSP 2", "DSP 3", "DSP 4", "DSP 5", "DSP 6", "DSP 7", "DSP 8"
};
set_voice_names( names );
set_gain( 1.4 );
}
Spc_Emu::~Spc_Emu() { }
// Track info
long const trailer_offset = 0x10200;
byte const* Spc_Emu::trailer() const { return &file_data [min( file_size, trailer_offset )]; }
long Spc_Emu::trailer_size() const { return max( 0L, file_size - trailer_offset ); }
static void get_spc_xid6( byte const* begin, long size, track_info_t* out )
{
// header
byte const* end = begin + size;
if ( size < 8 || memcmp( begin, "xid6", 4 ) )
{
check( false );
return;
}
long info_size = get_le32( begin + 4 );
byte const* in = begin + 8;
if ( end - in > info_size )
{
debug_printf( "Extra data after SPC xid6 info\n" );
end = in + info_size;
}
int year = 0;
char copyright [256 + 5];
int copyright_len = 0;
int const year_len = 5;
while ( end - in >= 4 )
{
// header
int id = in [0];
int data = in [3] * 0x100 + in [2];
int type = in [1];
int len = type ? data : 0;
in += 4;
if ( len > end - in )
{
check( false );
break; // block goes past end of data
}
// handle specific block types
char* field = 0;
switch ( id )
{
case 0x01: field = out->song; break;
case 0x02: field = out->game; break;
case 0x03: field = out->author; break;
case 0x04: field = out->dumper; break;
case 0x07: field = out->comment; break;
case 0x14: year = data; break;
//case 0x30: // intro length
// Many SPCs have intro length set wrong for looped tracks, making it useless
/*
case 0x30:
check( len == 4 );
if ( len >= 4 )
{
out->intro_length = get_le32( in ) / 64;
if ( out->length > 0 )
{
long loop = out->length - out->intro_length;
if ( loop >= 2000 )
out->loop_length = loop;
}
}
break;
*/
case 0x13:
copyright_len = min( len, (int) sizeof copyright - year_len );
memcpy( &copyright [year_len], in, copyright_len );
break;
default:
if ( id < 0x01 || (id > 0x07 && id < 0x10) ||
(id > 0x14 && id < 0x30) || id > 0x36 )
debug_printf( "Unknown SPC xid6 block: %X\n", (int) id );
break;
}
if ( field )
{
check( type == 1 );
Gme_File::copy_field_( field, (char const*) in, len );
}
// skip to next block
in += len;
// blocks are supposed to be 4-byte aligned with zero-padding...
byte const* unaligned = in;
while ( (in - begin) & 3 && in < end )
{
if ( *in++ != 0 )
{
// ...but some files have no padding
in = unaligned;
debug_printf( "SPC info tag wasn't properly padded to align\n" );
break;
}
}
}
char* p = &copyright [year_len];
if ( year )
{
*--p = ' ';
for ( int n = 4; n--; )
{
*--p = char (year % 10 + '0');
year /= 10;
}
copyright_len += year_len;
}
if ( copyright_len )
Gme_File::copy_field_( out->copyright, p, copyright_len );
check( in == end );
}
static void get_spc_info( Spc_Emu::header_t const& h, byte const* xid6, long xid6_size,
track_info_t* out )
{
// decode length (can be in text or binary format, sometimes ambiguous ugh)
long len_secs = 0;
for ( int i = 0; i < 3; i++ )
{
unsigned n = h.len_secs [i] - '0';
if ( n > 9 )
{
// ignore single-digit text lengths
// (except if author field is present and begins at offset 1, ugh)
if ( i == 1 && (h.author [0] || !h.author [1]) )
len_secs = 0;
break;
}
len_secs *= 10;
len_secs += n;
}
if ( !len_secs || len_secs > 0x1FFF )
len_secs = get_le16( h.len_secs );
if ( len_secs < 0x1FFF )
out->length = len_secs * 1000;
int offset = (h.author [0] < ' ' || unsigned (h.author [0] - '0') <= 9);
Gme_File::copy_field_( out->author, &h.author [offset], sizeof h.author - offset );
GME_COPY_FIELD( h, out, song );
GME_COPY_FIELD( h, out, game );
GME_COPY_FIELD( h, out, dumper );
GME_COPY_FIELD( h, out, comment );
if ( xid6_size )
get_spc_xid6( xid6, xid6_size, out );
}
blargg_err_t Spc_Emu::track_info_( track_info_t* out, int ) const
{
get_spc_info( header(), trailer(), trailer_size(), out );
return 0;
}
static blargg_err_t check_spc_header( void const* header )
{
if ( memcmp( header, "SNES-SPC700 Sound File Data", 27 ) )
return gme_wrong_file_type;
return 0;
}
struct Spc_File : Gme_Info_
{
Spc_Emu::header_t header;
blargg_vector<byte> xid6;
Spc_File() { set_type( gme_spc_type ); }
blargg_err_t load_( Data_Reader& in )
{
long file_size = in.remain();
if ( file_size < Snes_Spc::spc_file_size )
return gme_wrong_file_type;
RETURN_ERR( in.read( &header, Spc_Emu::header_size ) );
RETURN_ERR( check_spc_header( header.tag ) );
long const xid6_offset = 0x10200;
long xid6_size = file_size - xid6_offset;
if ( xid6_size > 0 )
{
RETURN_ERR( xid6.resize( xid6_size ) );
RETURN_ERR( in.skip( xid6_offset - Spc_Emu::header_size ) );
RETURN_ERR( in.read( xid6.begin(), xid6.size() ) );
}
return 0;
}
blargg_err_t track_info_( track_info_t* out, int ) const
{
get_spc_info( header, xid6.begin(), xid6.size(), out );
return 0;
}
};
static Music_Emu* new_spc_emu () { return BLARGG_NEW Spc_Emu ; }
static Music_Emu* new_spc_file() { return BLARGG_NEW Spc_File; }
static gme_type_t_ const gme_spc_type_ = { "Super Nintendo", 1, &new_spc_emu, &new_spc_file, "SPC", 0 };
gme_type_t const gme_spc_type = &gme_spc_type_;
// Setup
blargg_err_t Spc_Emu::set_sample_rate_( long sample_rate )
{
apu.set_gain( gain() );
if ( sample_rate != native_sample_rate )
{
RETURN_ERR( resampler.buffer_size( native_sample_rate / 20 * 2 ) );
resampler.time_ratio( (double) native_sample_rate / sample_rate, 0.9965 );
}
return 0;
}
void Spc_Emu::mute_voices_( int m )
{
Music_Emu::mute_voices_( m );
apu.mute_voices( m );
}
blargg_err_t Spc_Emu::load_mem_( byte const* in, long size )
{
assert( offsetof (header_t,unused2 [46]) == header_size );
file_data = in;
file_size = size;
set_voice_count( Snes_Spc::voice_count );
if ( size < Snes_Spc::spc_file_size )
return gme_wrong_file_type;
return check_spc_header( in );
}
// Emulation
void Spc_Emu::set_tempo_( double t ) { apu.set_tempo( t ); }
blargg_err_t Spc_Emu::start_track_( int track )
{
RETURN_ERR( Music_Emu::start_track_( track ) );
resampler.clear();
RETURN_ERR( apu.load_spc( file_data, file_size ) );
apu.clear_echo();
return 0;
}
blargg_err_t Spc_Emu::skip_( long count )
{
if ( sample_rate() != native_sample_rate )
{
count = long (count * resampler.ratio()) & ~1;
count -= resampler.skip_input( count );
}
// TODO: shouldn't skip be adjusted for the 64 samples read afterwards?
if ( count > 0 )
RETURN_ERR( apu.skip( count ) );
// eliminate pop due to resampler
const int resampler_latency = 64;
sample_t buf [resampler_latency];
return play_( resampler_latency, buf );
}
blargg_err_t Spc_Emu::play_( long count, sample_t* out )
{
if ( sample_rate() == native_sample_rate )
return apu.play( count, out );
long remain = count;
while ( remain > 0 )
{
remain -= resampler.read( &out [count - remain], remain );
if ( remain > 0 )
{
long n = resampler.max_write();
RETURN_ERR( apu.play( n, resampler.buffer() ) );
resampler.write( n );
}
}
check( remain == 0 );
return 0;
}

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