www.pudn.com > gspmidi101src.zip > readmidi.c
/*
TiMidity -- Experimental MIDI to WAVE converter
Copyright (C) 1995 Tuukka Toivonen
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 2 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, write to the Free Software
Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*/
#include
#include
#ifndef _WIN32_WCE
#include
#endif
#ifndef _WIN32_WCE
#include
#endif
#include "config.h"
#include "common.h"
#include "instrum.h"
#include "playmidi.h"
#include "readmidi.h"
#include "output.h"
int32 quietchannels=0;
/* to avoid some unnecessary parameter passing */
static MidiEventList *evlist;
static int32 event_count;
static FILE *fp;
static int32 at;
/* These would both fit into 32 bits, but they are often added in
large multiples, so it's simpler to have two roomy ints */
static int32 sample_increment, sample_correction; /*samples per MIDI delta-t*/
/* Computes how many (fractional) samples one MIDI delta-time unit contains */
static void compute_sample_increment(int32 tempo, int32 divisions)
{
double a;
a = (double) (tempo) * (double) (play_mode->rate) * (65536.0/1000000.0) /
(double)(divisions);
sample_correction = (int32)(a) & 0xFFFF;
sample_increment = (int32)(a) >> 16;
}
/* Read variable-length number (7 bits per byte, MSB first) */
static int32 getvl(void)
{
int32 l=0;
uint8 c;
for (;;)
{
fread(&c,1,1,fp);
l += (c & 0x7f);
if (!(c & 0x80)) return l;
l<<=7;
}
}
/* Print a string from the file, followed by a newline. Any non-ASCII
or unprintable characters will be converted to periods. */
static int dumpstring(int32 len, char *label)
{
signed char *s=safe_malloc(len+1);
if (len != fread(s, 1, len, fp))
{
free(s);
return -1;
}
s[len]='\0';
while (len--)
{
if (s[len]<32)
s[len]='.';
}
free(s);
return 0;
}
#define MIDIEVENT(at,t,ch,pa,pb) \
new=safe_malloc(sizeof(MidiEventList)); \
new->event.time=at; new->event.type=t; new->event.channel=ch; \
new->event.a=pa; new->event.b=pb; new->next=0;\
return new;
#define MAGIC_EOT ((MidiEventList *)(-1))
/* Read a MIDI event, returning a freshly allocated element that can
be linked to the event list */
static MidiEventList *read_midi_event(void)
{
static uint8 laststatus, lastchan;
static uint8 nrpn=0, rpn_msb[16], rpn_lsb[16]; /* one per channel */
uint8 me, type, a,b,c;
int32 len;
MidiEventList *new;
for (;;)
{
at+=getvl();
if (fread(&me,1,1,fp)!=1)
{
return 0;
}
if(me==0xF0 || me == 0xF7) /* SysEx event */
{
len=getvl();
skip(fp, len);
}
else if(me==0xFF) /* Meta event */
{
fread(&type,1,1,fp);
len=getvl();
if (type>0 && type<16)
{
static char *label[]={
"Text event: ", "Text: ", "Copyright: ", "Track name: ",
"Instrument: ", "Lyric: ", "Marker: ", "Cue point: "};
dumpstring(len, label[(type>7) ? 0 : type]);
}
else
switch(type)
{
case 0x2F: /* End of Track */
return MAGIC_EOT;
case 0x51: /* Tempo */
fread(&a,1,1,fp); fread(&b,1,1,fp); fread(&c,1,1,fp);
MIDIEVENT(at, ME_TEMPO, c, a, b);
default:
skip(fp, len);
break;
}
}
else
{
a=me;
if (a & 0x80) /* status byte */
{
lastchan=a & 0x0F;
laststatus=(a>>4) & 0x07;
fread(&a, 1,1, fp);
a &= 0x7F;
}
switch(laststatus)
{
case 0: /* Note off */
fread(&b, 1,1, fp);
b &= 0x7F;
MIDIEVENT(at, ME_NOTEOFF, lastchan, a,b);
case 1: /* Note on */
fread(&b, 1,1, fp);
b &= 0x7F;
MIDIEVENT(at, ME_NOTEON, lastchan, a,b);
case 2: /* Key Pressure */
fread(&b, 1,1, fp);
b &= 0x7F;
MIDIEVENT(at, ME_KEYPRESSURE, lastchan, a, b);
case 3: /* Control change */
fread(&b, 1,1, fp);
b &= 0x7F;
{
int control=255;
switch(a)
{
case 7: control=ME_MAINVOLUME; break;
case 10: control=ME_PAN; break;
case 11: control=ME_EXPRESSION; break;
case 64: control=ME_SUSTAIN; b = (b >= 64); break;
case 120: control=ME_ALL_SOUNDS_OFF; break;
case 121: control=ME_RESET_CONTROLLERS; break;
case 123: control=ME_ALL_NOTES_OFF; break;
/* These should be the SCC-1 tone bank switch
commands. I don't know why there are two, or
why the latter only allows switching to bank 0.
Also, some MIDI files use 0 as some sort of
continuous controller. This will cause lots of
warnings about undefined tone banks. */
case 0: control=ME_TONE_BANK; break;
case 32:
break;
case 100: nrpn=0; rpn_msb[lastchan]=b; break;
case 101: nrpn=0; rpn_lsb[lastchan]=b; break;
case 99: nrpn=1; rpn_msb[lastchan]=b; break;
case 98: nrpn=1; rpn_lsb[lastchan]=b; break;
case 6:
if (nrpn)
{
break;
}
switch((rpn_msb[lastchan]<<8) | rpn_lsb[lastchan])
{
case 0x0000: /* Pitch bend sensitivity */
control=ME_PITCH_SENS;
break;
case 0x7F7F: /* RPN reset */
/* reset pitch bend sensitivity to 2 */
MIDIEVENT(at, ME_PITCH_SENS, lastchan, 2, 0);
default:
break;
}
break;
default:
break;
}
if (control != 255)
{
MIDIEVENT(at, control, lastchan, b, 0);
}
}
break;
case 4: /* Program change */
a &= 0x7f;
MIDIEVENT(at, ME_PROGRAM, lastchan, a, 0);
case 5: /* Channel pressure - NOT IMPLEMENTED */
break;
case 6: /* Pitch wheel */
fread(&b, 1,1, fp);
b &= 0x7F;
MIDIEVENT(at, ME_PITCHWHEEL, lastchan, a, b);
default:
break;
}
}
}
return new;
}
#undef MIDIEVENT
/* Read a midi track into the linked list, either merging with any previous
tracks or appending to them. */
static int read_track(int append)
{
MidiEventList *meep;
MidiEventList *next, *new;
int32 len;
char tmp[4];
meep=evlist;
if (append && meep)
{
/* find the last event in the list */
for (; meep->next; meep=meep->next)
;
at=meep->event.time;
}
else
at=0;
/* Check the formalities */
if ((fread(tmp,1,4,fp) != 4) || (fread(&len,4,1,fp) != 1))
{
return -1;
}
len=BE_LONG(len);
if (memcmp(tmp, "MTrk", 4))
{
return -2;
}
for (;;)
{
if (!(new=read_midi_event())) /* Some kind of error */
return -2;
if (new==MAGIC_EOT) /* End-of-track Hack. */
{
return 0;
}
next=meep->next;
while (next && (next->event.time < new->event.time))
{
meep=next;
next=meep->next;
}
new->next=next;
meep->next=new;
event_count++; /* Count the event. (About one?) */
meep=new;
}
}
/* Free the linked event list from memory. */
static void free_midi_list(void)
{
MidiEventList *meep, *next;
if (!(meep=evlist)) return;
while (meep)
{
next=meep->next;
free(meep);
meep=next;
}
evlist=0;
}
/* Allocate an array of MidiEvents and fill it from the linked list of
events, marking used instruments for loading. Convert event times to
samples: handle tempo changes. Strip unnecessary events from the list.
Free the linked list. */
static MidiEvent *groom_list(int32 divisions,int32 *eventsp,int32 *samplesp)
{
MidiEvent *groomed_list, *lp;
MidiEventList *meep;
int32 i, our_event_count, tempo, skip_this_event, new_value;
int32 sample_cum, samples_to_do, at, st, dt, counting_time;
int current_bank[16], current_set[16], current_program[16];
/* Or should each bank have its own current program? */
for (i=0; i<16; i++)
{
current_bank[i]=0;
current_set[i]=0;
current_program[i]=default_program;
}
tempo=500000;
compute_sample_increment(tempo, divisions);
/* This may allocate a bit more than we need */
groomed_list=lp=safe_malloc(sizeof(MidiEvent) * (event_count+1));
meep=evlist;
our_event_count=0;
st=at=sample_cum=0;
counting_time=2; /* We strip any silence before the first NOTE ON. */
for (i=0; ievent.type==ME_TEMPO)
{
skip_this_event=1;
}
else switch (meep->event.type)
{
case ME_PROGRAM:
if (ISDRUMCHANNEL(meep->event.channel))
{
if (drumset[meep->event.a]) /* Is this a defined drumset? */
new_value=meep->event.a;
else
{
new_value=meep->event.a=0;
}
if (current_set[meep->event.channel] != new_value)
current_set[meep->event.channel]=new_value;
else
skip_this_event=1;
}
else
{
new_value=meep->event.a;
if ((current_program[meep->event.channel] != SPECIAL_PROGRAM)
&& (current_program[meep->event.channel] != new_value))
current_program[meep->event.channel] = new_value;
else
skip_this_event=1;
}
break;
case ME_NOTEON:
if (counting_time)
counting_time=1;
if (ISDRUMCHANNEL(meep->event.channel))
{
/* Mark this instrument to be loaded */
if (!(drumset[current_set[meep->event.channel]]
->tone[meep->event.a].instrument))
drumset[current_set[meep->event.channel]]
->tone[meep->event.a].instrument=
MAGIC_LOAD_INSTRUMENT;
}
else
{
if (current_program[meep->event.channel]==SPECIAL_PROGRAM)
break;
/* Mark this instrument to be loaded */
if (!(tonebank[current_bank[meep->event.channel]]
->tone[current_program[meep->event.channel]].instrument))
tonebank[current_bank[meep->event.channel]]
->tone[current_program[meep->event.channel]].instrument=
MAGIC_LOAD_INSTRUMENT;
}
break;
case ME_TONE_BANK:
if (ISDRUMCHANNEL(meep->event.channel))
{
skip_this_event=1;
break;
}
if (tonebank[meep->event.a]) /* Is this a defined tone bank? */
new_value=meep->event.a;
else
{
new_value=meep->event.a=0;
}
if (current_bank[meep->event.channel]!=new_value)
current_bank[meep->event.channel]=new_value;
else
skip_this_event=1;
break;
}
/* Recompute time in samples*/
if ((dt=meep->event.time - at) && !counting_time)
{
samples_to_do=sample_increment * dt;
sample_cum += sample_correction * dt;
if (sample_cum & 0xFFFF0000)
{
samples_to_do += ((sample_cum >> 16) & 0xFFFF);
sample_cum &= 0x0000FFFF;
}
st += samples_to_do;
}
else if (counting_time==1) counting_time=0;
if (meep->event.type==ME_TEMPO)
{
tempo=
meep->event.channel + meep->event.b * 256 + meep->event.a * 65536;
compute_sample_increment(tempo, divisions);
}
if (!skip_this_event)
{
/* Add the event to the list */
*lp=meep->event;
lp->time=st;
lp++;
our_event_count++;
}
at=meep->event.time;
meep=meep->next;
}
/* Add an End-of-Track event */
lp->time=st;
lp->type=ME_EOT;
our_event_count++;
free_midi_list();
*eventsp=our_event_count;
*samplesp=st;
return groomed_list;
}
MidiEvent *read_midi_file(FILE *mfp, int32 *count, int32 *sp)
{
int32 len, divisions;
int16 format, tracks, divisions_tmp;
int i;
char tmp[4];
fp=mfp;
event_count=0;
at=0;
evlist=0;
if ((fread(tmp,1,4,fp) != 4) || (fread(&len,4,1,fp) != 1))
{
return 0;
}
len=BE_LONG(len);
if (memcmp(tmp, "MThd", 4) || len < 6)
{
return 0;
}
fread(&format, 2, 1, fp);
fread(&tracks, 2, 1, fp);
fread(&divisions_tmp, 2, 1, fp);
format=BE_SHORT(format);
tracks=BE_SHORT(tracks);
divisions_tmp=BE_SHORT(divisions_tmp);
if (divisions_tmp<0)
{
/* SMPTE time -- totally untested. Got a MIDI file that uses this? */
divisions=
(int32)(-(divisions_tmp/256)) * (int32)(divisions_tmp & 0xFF);
}
else divisions=(int32)(divisions_tmp);
if (len > 6)
{
skip(fp, len-6); /* skip the excess */
}
if (format<0 || format >2)
{
return 0;
}
/* Put a do-nothing event first in the list for easier processing */
evlist=safe_malloc(sizeof(MidiEventList));
evlist->event.time=0;
evlist->event.type=ME_NONE;
evlist->next=0;
event_count++;
switch(format)
{
case 0:
if (read_track(0))
{
free_midi_list();
return 0;
}
break;
case 1:
for (i=0; i