ref: ec73849b6936d839410ccb239d14b2f7c7ca3d6f
dir: /sys/src/games/midi/midifile.c/
#include <u.h> #include <libc.h> #include <bio.h> #include "midifile.h" Track *tracks; Chan chan[Nchan]; Inst *inst; int mfmt, ntrk, div = 1, tempo = 500000; int samprate = Rate; int trace, stream, writeback; vlong tic; Biobuf *inbf, *outbf; int rate = Rate; void * emalloc(ulong n) { void *p; p = mallocz(n, 1); if(p == nil) sysfatal("mallocz: %r"); setmalloctag(p, getcallerpc(&n)); return p; } void * erealloc(void *p, usize n, usize oldn) { if((p = realloc(p, n)) == nil) sysfatal("realloc: %r"); setrealloctag(p, getcallerpc(&p)); if(n > oldn) memset((uchar *)p + oldn, 0, n - oldn); return p; } 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); } Biobuf * efdopen(int fd, int mode) { Biobuf *bf; if((bf = Bfdopen(fd, mode)) == nil) sysfatal("efdopen: %r"); Blethal(bf, nil); return bf; } Biobuf * eopen(char *file, int mode) { int fd; if((fd = open(file, mode)) < 0) sysfatal("eopen: %r"); return efdopen(fd, mode); } u8int get8(Track *t) { u8int v; if(t == nil || t->cur == nil || t->buf == nil) Bread(inbf, &v, 1); else{ if(t->cur >= t->buf + t->bufsz || t->ended) sysfatal("track overflow"); v = *t->cur++; } return v; } u16int get16(Track *t) { u16int v; v = get8(t) << 8; return v | get8(t); } u32int get32(Track *t) { u32int v; v = get16(t) << 16; return v | get16(t); } static void growmid(Track *t, int n) { usize cur, run; /* one extra byte for delay prefetch */ if(t->cur + n + 1 < t->buf + t->bufsz) return; cur = t->cur - t->buf; run = t->run - t->buf; if(n < 8192) n = 8192; t->buf = erealloc(t->buf, t->bufsz + n + 1, t->bufsz); t->bufsz += n + 1; t->cur = t->buf + cur; t->run = t->buf + run; } static void put8(Track *t, u8int v) { if(t != nil){ growmid(t, 1); *t->cur++ = v; }else Bwrite(outbf, &v, 1); } static void put16(Track *t, u16int v) { put8(t, v >> 8); put8(t, v); } static void put32(Track *t, u32int v) { put16(t, v >> 16); put16(t, v); } static void putvar(Track *t) { int w; uchar u[4], *p; p = u + nelem(u) - 1; w = t->Δ; if(w & 1<<31) sysfatal("invalid variable-length number %08ux", w); *p-- = w; while(w >= 0x80){ w >>= 8; *p-- = w; } Bwrite(outbf, p, u + sizeof(u) - 1 - p); } static int getvar(Track *t) { int n, v, w; w = get8(t); v = w & 0x7f; for(n=0; w&0x80; n++){ if(n == 3) sysfatal("invalid variable-length number"); v <<= 7; w = get8(t); v |= w & 0x7f; } return v; } u32int peekvar(Track *t) { uchar *cur; uint v; cur = t->cur; v = getvar(t); t->cur = cur; return v; } static void skip(Track *t, int n) { while(n-- > 0) get8(t); } double delay(double n) { return (n * tempo * samprate / div) / 1e6; } vlong ns2tic(double n) { return n * div * 1e3 / tempo; } int nextev(Track *t) { int e; if(writeback) putvar(t); t->run = t->cur; e = get8(t); if((e & 0x80) == 0){ if(t->cur != nil){ t->cur--; t->run--; } e = t->latch; if((e & 0x80) == 0) sysfatal("invalid event %#ux", e); }else t->latch = e; return e; } static void newmsg(Msg *m, int c, int type, int arg1, int arg2, usize size) { m->chan = chan + c; m->type = type; m->arg1 = arg1; m->arg2 = arg2; m->size = size; } void translate(Track *t, int e, Msg *msg) { int c, n, m, type; uchar *p; c = e & 0xf; dprint("Δ %.2f ch%02d ", t->Δ, c); n = get8(t); m = -1; type = Cunknown; switch(e >> 4){ case 0x8: m = get8(t); dprint("note off\t%02ux\taftertouch\t%02ux", n, m); type = Cnoteoff; break; case 0x9: m = get8(t); dprint("note on\t%02ux\tvelocity\t%02ux", n, m); type = Cnoteon; break; case 0xb: m = get8(t); dprint("control change: "); switch(n){ case 0x00: dprint("bank select msb\t%02ux", m); type = Cbankmsb; break; case 0x07: dprint("channel volume\t%02ux", m); chan[c].vol = m; type = Cchanvol; break; case 0x0a: dprint("pan\t%02ux", m); chan[c].pan = m < 32 ? 1<<4 : m > 96 ? 1<<5 : 3<<4; type = Cpan; break; default: dprint("unknown controller %.4ux", n); break; } break; case 0xc: dprint("program change\t%02ux", n); type = Cprogram; break; case 0xe: n = (get8(t) << 7 | n) - 0x4000 / 2; chan[c].bend = n; dprint("pitch bend\t%02x", n); type = Cpitchbend; break; case 0xf: dprint("sysex:\t"); if((e & 0xf) == 0){ m = 0; while(get8(t) != 0xf7) m++; fprint(2, "sysex n %d m %d\n", n, m); type = Csysex; break; } m = get8(t); switch(n){ case 0x2f: dprint("... so long!"); t->ended = 1; type = Ceot; break; case 0x51: tempo = get16(t) << 8; tempo |= get8(t); dprint("tempo change\t%d", tempo); type = Ctempo; break; default: dprint("skipping unhandled event %02ux", n); skip(t, m); break; } break; case 0xa: m = get8(t); dprint("polyphonic key pressure/aftertouch\t%02ux\t%02ux", n, m); type = Ckeyafter; break; case 0xd: m = get8(t); dprint("channel pressure/aftertouch\t%02ux\t%02ux", n, m); type = Cchanafter; break; default: sysfatal("invalid event %#ux", e >> 4); } newmsg(msg, c, type, n, m, t->cur - t->run); dprint("\t["); for(p=t->run; p<t->cur; p++) dprint("%02ux", *p); dprint("]\n"); } void writemid(char *file) { u32int n; Track *t; outbf = file == nil ? efdopen(1, OWRITE) : eopen(file, OWRITE); put32(nil, 0x4d546864); /* MThd */ put32(nil, 6); put16(nil, mfmt); put16(nil, ntrk); put16(nil, div); for(t=tracks; t<tracks+ntrk; t++){ put32(nil, 0x4d54726b); /* MTrack */ n = t->cur - t->buf; put32(nil, n); Bwrite(outbf, t->buf, n); } Bterm(outbf); outbf = nil; } int readmid(char *file) { u32int n, z; Track *t; inbf = file == nil ? efdopen(0, OREAD) : eopen(file, OREAD); if(stream){ mfmt = 0; ntrk = 1; tracks = emalloc(ntrk * sizeof *tracks); return 0; } if(get32(nil) != 0x4d546864 || get32(nil) != 6){ werrstr("invalid header"); return -1; } mfmt = get16(nil); ntrk = get16(nil); if(ntrk == 1) mfmt = 0; if(mfmt < 0 || mfmt > 1){ werrstr("unsupported format %d", mfmt); return -1; } div = get16(nil); tracks = emalloc(ntrk * sizeof *tracks); for(t=tracks, z=-1UL; t<tracks+ntrk; t++){ if(get32(nil) != 0x4d54726b){ werrstr("invalid track"); return -1; } n = get32(nil); growmid(t, n); Bread(inbf, t->buf, n); t->Δ = getvar(t); /* prearm */ if(t->Δ < z) z = t->Δ; } for(t=tracks; t<tracks+ntrk; t++) t->Δ -= z; Bterm(inbf); inbf = nil; return 0; } void evloop(void) { int end; Track *t; if(stream){ for(t=tracks;;){ t->Δ = getvar(t); event(t); if(t->ended) return; samp(1); tic++; } } for(;;){ end = 1; for(t=tracks; t<tracks+ntrk; t++){ if(t->ended) continue; end = 0; t->Δ--; t->t += delay(1); while(t->Δ <= 0){ event(t); if(t->ended) break; t->Δ = getvar(t); } } if(end) break; samp(1); tic++; } } void initmid(void) { Chan *c; for(c=chan; c<chan+nelem(chan); c++){ c->vol = 0x5a; c->bend = 0; c->pan = 3<<4; } }