ref: 1e95b1cbb2a05e23ada69db3093b1a3d389c97f3
parent: 103c1ae3c97f64130cc4ed787517a3930ba0add5
author: qwx <qwx@sciops.net>
date: Thu Mar 16 02:06:53 EDT 2023
wip midi tools, state of the game mid2s: stream midi file midump: formatted midi event dump (very wip)
--- /dev/null
+++ b/mid2s.c
@@ -1,0 +1,339 @@
+#include <u.h>
+#include <libc.h>
+#include <bio.h>
+
+enum{+ Rate = 44100,
+ Nchan = 16,//6,
+ Percch = 9,//5,
+};
+
+typedef struct Trk Trk;
+struct Trk{+ u8int *s;
+ u8int *p;
+ u8int *q;
+ u8int *e;
+ double Δ;
+ double t;
+ int ev;
+ int ended;
+ int chan[16];
+};
+Trk *tr;
+int chan[16];
+
+int trace;
+int mfmt, ntrk, div = 1, tempo;
+Biobuf *ib;
+
+void *
+emalloc(ulong n)
+{+ void *p;
+
+ p = mallocz(n, 1);
+ if(p == nil)
+ sysfatal("mallocz: %r");+ setmalloctag(p, getcallerpc(&n));
+ return p;
+}
+
+Biobuf *
+bfdopen(int fd, int mode)
+{+ Biobuf *bf;
+
+ bf = Bfdopen(fd, mode);
+ if(bf == nil)
+ sysfatal("bfdopen: %r");+ Blethal(bf, nil);
+ return bf;
+}
+
+Biobuf *
+bopen(char *file, int mode)
+{+ int fd;
+
+ fd = open(file, mode);
+ if(fd < 0)
+ sysfatal("bopen: %r");+ return bfdopen(fd, mode);
+}
+
+void
+bread(void *u, int n)
+{+ if(Bread(ib, u, n) != n)
+ sysfatal("bread: short read");+}
+
+void
+dprint(char *fmt, ...)
+{+ char s[256];
+ va_list arg;
+
+ if(!trace)
+ return;
+ va_start(arg, fmt);
+ vseprint(s, s+sizeof s, fmt, arg);
+ va_end(arg);
+ fprint(2, "%s", s);
+}
+
+u8int
+get8(Trk *x)
+{+ u8int v;
+
+ if(x == nil)
+ Bread(ib, &v, 1);
+ else{+ if(x->p >= x->e || x->ended)
+ sysfatal("track overflow");+ v = *x->p++;
+ }
+ dprint("%02ux", v);+ return v;
+}
+
+u16int
+get16(Trk *x)
+{+ u16int v;
+
+ v = get8(x) << 8;
+ return v | get8(x);
+}
+
+u32int
+get32(Trk *x)
+{+ u32int v;
+
+ v = get16(x) << 16;
+ return v | get16(x);
+}
+
+double
+tc(double n)
+{+ return (n * tempo / div);
+}
+
+void
+skip(Trk *x, int n)
+{+ while(n-- > 0)
+ get8(x);
+}
+
+int
+getvar(Trk *x)
+{+ int v, w;
+
+ w = get8(x);
+ v = w & 0x7f;
+ while(w & 0x80){+ if(v & 0xff000000)
+ sysfatal("invalid variable-length number");+ v <<= 7;
+ w = get8(x);
+ v |= w & 0x7f;
+ }
+ return v;
+}
+
+void
+samp(double n)
+{+ double Δ;
+ long t;
+ static double ε;
+
+ /* FIXME: using nsec() might help with desyncs? ie. account for drift? */
+ Δ = n * 1000 * tempo / div + ε;
+ t = floor(Δ / 1000000);
+ ε = Δ - t * 1000000;
+ sleep(t);
+}
+
+int
+mapinst(Trk *x, int c, int e)
+{+ int i;
+
+ if(e >> 4 == 0xf)
+ return e;
+ if(e >> 4 != 0x9 || x->chan[c] >= 0)
+ return e;
+ if(c == 9)
+ i = Percch;
+ else if(chan[c] >= 0)
+ return e;
+ else{+ for(i=0; i<Nchan; i++){+ if(i == Percch)
+ continue;
+ if(chan[i] < 0)
+ break;
+ }
+ /* hope for the best; either ignore it,
+ * or hope the last channel isn't one of the main ones,
+ * which is usually the case; but we no longer have our
+ * settings */
+ if(i == Nchan)
+ i = Nchan-2;
+ }
+ x->chan[c] = i;
+ chan[i] = Nchan * (x - tr) + c;
+ return e & ~(16-1) | i;
+}
+
+int
+ev(Trk *x, vlong)
+{+ int e, n, m;
+
+ x->q = x->p - 1;
+ //*x->q = 0;
+ dprint(" [%zd] ", x - tr);+ e = get8(x);
+ if((e & 0x80) == 0){+ x->p--;
+ e = x->ev;
+ x->q--;
+ //x->q[0] = 0;
+ x->q[1] = e;
+ if((e & 0x80) == 0)
+ sysfatal("invalid event");+ }else
+ x->ev = e;
+ dprint("(%02ux) ", e);+
+ e = mapinst(x, e & 15, e);
+
+ n = get8(x);
+ switch(e >> 4){+ case 0x8: get8(x); break;
+ case 0x9: get8(x); break;
+ case 0xb: get8(x); break;
+ case 0xc: break;
+ case 0xe: get8(x); break;
+ case 0xf:
+ if((e & 0xf) == 0){+ while(get8(x) != 0xf7)
+ ;
+ break;
+ }
+ m = get8(x);
+ switch(n){+ case 0x2f: dprint(" -- so long!\n"); return -1;+ case 0x51: tempo = get16(x) << 8; tempo |= get8(x); break;
+ default: skip(x, m);
+ }
+ break;
+ case 0xa: get8(x); break;
+ case 0xd: get8(x); break;
+ default: sysfatal("invalid event %#ux\n", e >> 4);+ }
+ dprint("\n");+ if(x->p > x->q){+ x->q[1] = e;
+ x->q[0] = x->q[1] >> 4 | (x->q[1] & 0xff) << 4;
+ write(1, x->q, x->p - x->q);
+ x->q = x->p;
+ }
+ return 0;
+}
+
+void
+readmid(char *file)
+{+ u32int n, z;
+ uchar *s;
+ Trk *x;
+
+ ib = file != nil ? bopen(file, OREAD) : bfdopen(0, OREAD);
+ if(get32(nil) != 0x4d546864 || get32(nil) != 6)
+ sysfatal("invalid header");+ mfmt = get16(nil);
+ ntrk = get16(nil);
+ if(ntrk == 1)
+ mfmt = 0;
+ if(mfmt < 0 || mfmt > 1)
+ sysfatal("unsupported format %d", mfmt);+ div = get16(nil);
+ tr = emalloc(ntrk * sizeof *tr);
+ for(x=tr, z=-1UL; x<tr+ntrk; x++){+ if(get32(nil) != 0x4d54726b)
+ sysfatal("invalid track");+ n = get32(nil);
+ s = emalloc(n);
+ bread(s, n);
+ x->s = s;
+ x->p = s;
+ x->q = x->p;
+ x->e = s + n;
+ memset(x->chan, 0x80, sizeof x->chan);
+ x->Δ = getvar(x); /* prearm */
+ if(x->Δ < z)
+ z = x->Δ;
+ }
+ for(x=tr; x<tr+ntrk; x++)
+ x->Δ -= z;
+ Bterm(ib);
+}
+
+void
+usage(void)
+{+ fprint(2, "usage: %s [-D] [mid]\n", argv0);
+ exits("usage");+}
+
+void
+main(int argc, char **argv)
+{+ int end, debug;
+ Trk *x;
+
+ debug = 0;
+ ARGBEGIN{+ case 'D': debug = 1; break;
+ default: usage();
+ }ARGEND
+ readmid(*argv);
+ memset(chan, 0x80, sizeof chan);
+ tempo = 500000;
+ trace = debug;
+ for(;;){+ end = 1;
+ for(x=tr; x<tr+ntrk; x++){+ if(x->ended)
+ continue;
+ end = 0;
+ x->Δ--;
+ while(x->Δ <= 0){+ if(x->ended = ev(x, 0)){+ int c = x - tr;
+ for(int i=0; i<Nchan; i++){+ if(chan[i] == c + i)
+ chan[i] = -1;
+ }
+ break;
+ }
+ x->Δ = getvar(x);
+ }
+ }
+ if(end){+ write(1, tr[0].q, tr[0].p - tr[0].q);
+ break;
+ }
+ samp(1);
+ }
+ exits(nil);
+}
--- /dev/null
+++ b/midump.c
@@ -1,0 +1,332 @@
+#include <u.h>
+#include <libc.h>
+#include <bio.h>
+
+enum{+ Rate = 44100,
+ Ninst = 128 + 81-35+1,
+};
+
+typedef struct Trk Trk;
+struct Trk{+ u8int *s;
+ u8int *p;
+ u8int *e;
+ double Δ;
+ double t;
+ int ev;
+ int ended;
+};
+Trk *tr;
+
+int desc, quiet;
+int mfmt, ntrk, div = 1, tempo;
+vlong tic;
+Biobuf *ib;
+
+void *
+emalloc(ulong n)
+{+ void *p;
+
+ p = mallocz(n, 1);
+ if(p == nil)
+ sysfatal("mallocz: %r");+ setmalloctag(p, getcallerpc(&n));
+ return p;
+}
+
+void
+dprint(char *fmt, ...)
+{+ char s[256];
+ va_list arg;
+
+ if(!desc)
+ return;
+ va_start(arg, fmt);
+ vseprint(s, s+sizeof s, fmt, arg);
+ va_end(arg);
+ fprint(2, "%s", s);
+}
+
+Biobuf *
+bfdopen(int fd, int mode)
+{+ Biobuf *bf;
+
+ bf = Bfdopen(fd, mode);
+ if(bf == nil)
+ sysfatal("bfdopen: %r");+ Blethal(bf, nil);
+ return bf;
+}
+
+Biobuf *
+bopen(char *file, int mode)
+{+ int fd;
+
+ fd = open(file, mode);
+ if(fd < 0)
+ sysfatal("bopen: %r");+ return bfdopen(fd, mode);
+}
+
+void
+bread(void *u, int n)
+{+ if(Bread(ib, u, n) != n)
+ sysfatal("bread: short read");+}
+
+u8int
+get8(Trk *x)
+{+ u8int v;
+
+ if(x == nil || x->p == nil || x->e == nil)
+ Bread(ib, &v, 1);
+ else{+ if(x->p >= x->e || x->ended)
+ sysfatal("track overflow");+ v = *x->p++;
+ }
+ if(!quiet)
+ print("%02hhux", v);+ return v;
+}
+
+u16int
+get16(Trk *x)
+{+ u16int v;
+
+ v = get8(x) << 8;
+ return v | get8(x);
+}
+
+u32int
+get32(Trk *x)
+{+ u32int v;
+
+ v = get16(x) << 16;
+ return v | get16(x);
+}
+
+double
+tc(double n)
+{+ return (n * tempo * Rate / div) / 1e6;
+}
+
+void
+skip(Trk *x, int n)
+{+ while(n-- > 0)
+ get8(x);
+}
+
+int
+getvar(Trk *x)
+{+ int v, w;
+
+ w = get8(x);
+ v = w & 0x7f;
+ while(w & 0x80){+ if(v & 0xff000000)
+ sysfatal("invalid variable-length number");+ v <<= 7;
+ w = get8(x);
+ v |= w & 0x7f;
+ }
+ return v;
+}
+
+int
+ev(Trk *x)
+{+ int e, n, m;
+
+ dprint("%08lld ", tic);+ print("[%02zd] ", x-tr);+ quiet = 1;
+ e = get8(x);
+ quiet = 0;
+ if((e & 0x80) == 0){+ x->p--;
+ e = x->ev;
+ print("%02ux*", e);+ if((e & 0x80) == 0)
+ sysfatal("invalid event");+ }else{+ print("%02ux", e);+ x->ev = e;
+ }
+ dprint("C%02d: %1ux ", e & 15, e >> 4);+ n = get8(x);
+ switch(e >> 4){+ case 0x8:
+ m = get8(x);
+ dprint("C%02d note off %02ux, aftertouch %02ux", e&0xf, n, m);+ break;
+ case 0x9:
+ m = get8(x);
+ dprint("C%02d note on %02ux, velocity %02ux", e&0xf, n, m);+ break;
+ case 0xb:
+ m = get8(x);
+ dprint("control change: ");+ switch(n){+ case 0x00: dprint("C%02d bank select msb %02ux", e&0xf, m); break;+ case 0x07: dprint("C%02d channel volume %02ux", e&0xf, m); break;+ case 0x0a: dprint("C%02d pan %02ux", e&0xf, m); break;+ default: dprint("C%02d unknown controller %.4ux = %02ux", e&0xf, n, m);+ }
+ break;
+ case 0xc: dprint("program change %02ux", e&0xf, n); break;+ case 0xe:
+ n = get8(x) << 7 | n;
+ dprint("pitch bend change %02x", n - 0x4000 / 2);+ break;
+ case 0xf:
+ dprint("sysex: ");+ if((e & 0xf) == 0){+ while(get8(x) != 0xf7)
+ ;
+ break;
+ }
+ m = get8(x);
+ dprint("[%d] ", m);+ switch(n){+ case 0x2f: print(" -- so long!\n"); return -1;+ case 0x51:
+ tempo = get16(x) << 8;
+ tempo |= get8(x);
+ dprint("tempo change %d", tempo);+ break;
+ default: skip(x, m);
+ }
+ break;
+ case 0xa:
+ m = get8(x);
+ dprint("polyphonic key pressure/aftertouch %02ux", m);+ break;
+ case 0xd:
+ m = get8(x);
+ dprint("channel pressure/aftertouch %02ux", m);+ break;
+ default: sysfatal("invalid event %#ux", e >> 4);+ }
+ print("\n");+ return 0;
+}
+
+void
+readmid(char *file)
+{+ u32int n, z;
+ uchar *s;
+ Trk *x;
+
+ ib = file != nil ? bopen(file, OREAD) : bfdopen(0, OREAD);
+ if(get32(nil) != 0x4d546864 || get32(nil) != 6)
+ sysfatal("invalid header");+ mfmt = get16(nil);
+ ntrk = get16(nil);
+ if(ntrk == 1)
+ mfmt = 0;
+
+ switch(mfmt){+ case 0: dprint("format 0: single multi-channel track\n"); break;+ case 1: dprint("format 1: multiple concurrent tracks\n"); break;+ case 2: dprint("format 2: multiple independent tracks\n"); break;+ }
+ dprint("%d tracks\n", ntrk);+
+ if(mfmt < 0 || mfmt > 1)
+ sysfatal("unsupported format %d", mfmt);+ div = get16(nil);
+ if(1) /* FIXME: properly introduce new members, etc. */
+ dprint("div: %d ticks per quarter note\n", div);+ else
+ dprint("div: %d smpte format, %d ticks per frame\n", (s16int)div>>8, div & 0xff);+ tr = emalloc(ntrk * sizeof *tr);
+ print("\n");+ for(x=tr, z=-1UL; x<tr+ntrk; x++){+ if(get32(nil) != 0x4d54726b)
+ sysfatal("invalid track");+ n = get32(nil);
+ dprint("track %zd, %d bytes\n", x-tr, n);+ s = emalloc(n);
+ bread(s, n);
+ x->s = s;
+ x->p = s;
+ x->e = s + n;
+ x->Δ = getvar(x); /* prearm */
+ if(x->Δ < z)
+ z = x->Δ;
+ print("\n");+ }
+ for(x=tr; x<tr+ntrk; x++)
+ x->Δ -= z;
+ tic = z;
+ Bterm(ib);
+}
+
+void
+usage(void)
+{+ fprint(2, "usage: %s [mid]\n", argv0);
+ exits("usage");+}
+
+void
+main(int argc, char **argv)
+{+ int end, stream;
+ Trk *x, ☺;
+
+ desc = 1;
+ stream = 0;
+ ARGBEGIN{+ case 'b': desc = 0; break;
+ case 's': stream = 1; break;
+ default: usage();
+ }ARGEND
+ tempo = 500000;
+ if(stream){+ ib = *argv != nil ? bopen(*argv, OREAD) : bfdopen(0, OREAD);
+ tr = &☺;
+ ntrk = 1;
+ memset(tr, 0, sizeof *tr);
+ for(;;){+ getvar(&☺);
+ if(ev(&☺) < 0)
+ exits(nil);
+ }
+ }
+ readmid(*argv);
+ for(end=0; !end;){+ end = 1;
+ for(x=tr; x<tr+ntrk; x++){+ if(x->ended)
+ continue;
+ end = 0;
+ x->Δ--;
+ x->t += tc(1);
+ while(x->Δ <= 0){+ if(x->ended = ev(x)){+ x->p = x->e;
+ break;
+ }
+ x->Δ = getvar(x);
+ print(" ");+ }
+ }
+ tic++;
+ }
+ exits(nil);
+}
--- a/mkfile
+++ b/mkfile
@@ -9,6 +9,8 @@
spd\
tev\
wstat\
+ mid2s\
+ midump\
HFILES=
YFLAGS=-D