gzdoom-gles/src/mus2midi.cpp
2016-03-01 09:47:10 -06:00

309 lines
6.9 KiB
C++

/*
** mus2midi.cpp
** Simple converter from MUS to MIDI format
**
**---------------------------------------------------------------------------
** Copyright 1998-2006 Randy Heit
** All rights reserved.
**
** Redistribution and use in source and binary forms, with or without
** modification, are permitted provided that the following conditions
** are met:
**
** 1. Redistributions of source code must retain the above copyright
** notice, this list of conditions and the following disclaimer.
** 2. Redistributions in binary form must reproduce the above copyright
** notice, this list of conditions and the following disclaimer in the
** documentation and/or other materials provided with the distribution.
** 3. The name of the author may not be used to endorse or promote products
** derived from this software without specific prior written permission.
**
** THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
** IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
** OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
** IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
** INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
** NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
** DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
** THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
** (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
** THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
**---------------------------------------------------------------------------
**
** MUS files are essentially format 0 MIDI files with some
** space-saving modifications. Conversion is quite straight-forward.
** If you were to hook a main() into this that calls ProduceMIDI,
** you could create a self-contained MUS->MIDI converter.
*/
#include <string.h>
#include "m_swap.h"
#include "mus2midi.h"
#include "doomdef.h"
static const BYTE StaticMIDIhead[] =
{ 'M','T','h','d', 0, 0, 0, 6,
0, 0, // format 0: only one track
0, 1, // yes, there is really only one track
0, 70, // 70 divisions
'M','T','r','k', 0, 0, 0, 0,
// The first event sets the tempo to 500,000 microsec/quarter note
0, 255, 81, 3, 0x07, 0xa1, 0x20
};
extern int MUSHeaderSearch(const BYTE *head, int len);
static const BYTE CtrlTranslate[15] =
{
0, // program change
0, // bank select
1, // modulation pot
7, // volume
10, // pan pot
11, // expression pot
91, // reverb depth
93, // chorus depth
64, // sustain pedal
67, // soft pedal
120, // all sounds off
123, // all notes off
126, // mono
127, // poly
121, // reset all controllers
};
static size_t ReadVarLen (const BYTE *buf, int *time_out)
{
int time = 0;
size_t ofs = 0;
BYTE t;
do
{
t = buf[ofs++];
time = (time << 7) | (t & 127);
} while (t & 128);
*time_out = time;
return ofs;
}
static size_t WriteVarLen (TArray<BYTE> &file, int time)
{
long buffer;
size_t ofs;
buffer = time & 0x7f;
while ((time >>= 7) > 0)
{
buffer = (buffer << 8) | 0x80 | (time & 0x7f);
}
for (ofs = 0;;)
{
file.Push(BYTE(buffer & 0xff));
if (buffer & 0x80)
buffer >>= 8;
else
break;
}
return ofs;
}
bool ProduceMIDI (const BYTE *musBuf, int len, TArray<BYTE> &outFile)
{
BYTE midStatus, midArgs, mid1, mid2;
size_t mus_p, maxmus_p;
BYTE event;
int deltaTime;
const MUSHeader *musHead;
BYTE status;
BYTE chanUsed[16];
BYTE lastVel[16];
long trackLen;
bool no_op;
// Find the header
int offset = MUSHeaderSearch(musBuf, len);
if (offset < 0 || offset + (int)sizeof(MUSHeader) >= len)
return false;
musBuf += offset;
len -= offset;
musHead = (const MUSHeader *)musBuf;
// Do some validation of the MUS file
if (LittleShort(musHead->NumChans) > 15)
return false;
// Prep for conversion
outFile.Clear();
outFile.Reserve(sizeof(StaticMIDIhead));
memcpy(&outFile[0], StaticMIDIhead, sizeof(StaticMIDIhead));
musBuf += LittleShort(musHead->SongStart);
mus_p = 0;
maxmus_p = LittleShort(musHead->SongLen);
if ((size_t)len - LittleShort(musHead->SongStart) < maxmus_p)
{
maxmus_p = len - LittleShort(musHead->SongStart);
}
memset (lastVel, 100, 16);
memset (chanUsed, 0, 16);
event = 0;
deltaTime = 0;
status = 0;
while (mus_p < maxmus_p && (event & 0x70) != MUS_SCOREEND)
{
int channel;
BYTE t = 0;
event = musBuf[mus_p++];
if ((event & 0x70) != MUS_SCOREEND)
{
t = musBuf[mus_p++];
}
channel = event & 15;
if (channel == 15)
{
channel = 9;
}
else if (channel >= 9)
{
channel++;
}
if (!chanUsed[channel])
{
// This is the first time this channel has been used,
// so sets its volume to 127.
chanUsed[channel] = 1;
outFile.Push(0);
outFile.Push(0xB0 | channel);
outFile.Push(7);
outFile.Push(127);
}
midStatus = channel;
midArgs = 0; // Most events have two args (0 means 2, 1 means 1)
no_op = false;
switch (event & 0x70)
{
case MUS_NOTEOFF:
midStatus |= MIDI_NOTEON;
mid1 = t & 127;
mid2 = 0;
break;
case MUS_NOTEON:
midStatus |= MIDI_NOTEON;
mid1 = t & 127;
if (t & 128)
{
lastVel[channel] = musBuf[mus_p++] & 127;
}
mid2 = lastVel[channel];
break;
case MUS_PITCHBEND:
midStatus |= MIDI_PITCHBEND;
mid1 = (t & 1) << 6;
mid2 = (t >> 1) & 127;
break;
case MUS_SYSEVENT:
if (t < 10 || t > 14)
{
no_op = true;
}
else
{
midStatus |= MIDI_CTRLCHANGE;
mid1 = CtrlTranslate[t];
mid2 = t == 12 /* Mono */ ? LittleShort(musHead->NumChans) : 0;
}
break;
case MUS_CTRLCHANGE:
if (t == 0)
{ // program change
midArgs = 1;
midStatus |= MIDI_PRGMCHANGE;
mid1 = musBuf[mus_p++] & 127;
mid2 = 0; // Assign mid2 just to make GCC happy
}
else if (t > 0 && t < 10)
{
midStatus |= MIDI_CTRLCHANGE;
mid1 = CtrlTranslate[t];
mid2 = musBuf[mus_p++];
}
else
{
no_op = true;
}
break;
case MUS_SCOREEND:
midStatus = MIDI_META;
mid1 = MIDI_META_EOT;
mid2 = 0;
break;
default:
return false;
}
if (no_op)
{
// A system-specific event with no data is a no-op.
midStatus = MIDI_META;
mid1 = MIDI_META_SSPEC;
mid2 = 0;
}
WriteVarLen (outFile, deltaTime);
if (midStatus != status)
{
status = midStatus;
outFile.Push(status);
}
outFile.Push(mid1);
if (midArgs == 0)
{
outFile.Push(mid2);
}
if (event & 128)
{
mus_p += ReadVarLen (&musBuf[mus_p], &deltaTime);
}
else
{
deltaTime = 0;
}
}
// fill in track length
trackLen = outFile.Size() - 22;
outFile[18] = BYTE((trackLen >> 24) & 255);
outFile[19] = BYTE((trackLen >> 16) & 255);
outFile[20] = BYTE((trackLen >> 8) & 255);
outFile[21] = BYTE(trackLen & 255);
return true;
}
bool ProduceMIDI(const BYTE *musBuf, int len, FILE *outFile)
{
TArray<BYTE> work;
if (ProduceMIDI(musBuf, len, work))
{
return fwrite(&work[0], 1, work.Size(), outFile) == work.Size();
}
return false;
}