ref: 3b9b7a6ab8b6e8c5eb37937b849d1e9f6106a386
parent: 2279c8609158c96b021fa437ee46c73b19bc179e
author: aiju <[email protected]>
date: Sat Apr 14 10:44:15 EDT 2012
added midi player
--- /dev/null
+++ b/sys/src/games/midi.c
@@ -1,0 +1,250 @@
+#include <u.h>
+#include <libc.h>
+
+enum { SAMPLE = 44100 };+
+struct Tracker {+ uchar *data;
+ char ended;
+ uvlong t;
+ uchar notes[16][128];
+ int cmd;
+} *tr;
+
+typedef struct Tracker Tracker;
+
+int fd, ofd, div, tempo = 500000, ntrack;
+uvlong T;
+int freq[128];
+
+void *
+emallocz(int size)
+{+ void *v;
+
+ v = malloc(size);
+ if(v == nil)
+ sysfatal("malloc: %r");+ memset(v, 0, size);
+ return v;
+}
+
+int
+get8(Tracker *src)
+{+ uchar c;
+
+ if(src == nil){+ if(read(fd, &c, 1) == 0)
+ sysfatal("unexpected eof");+ return c;
+ }
+ return *src->data++;
+}
+
+int
+get16(Tracker *src)
+{+ int x;
+
+ x = get8(src) << 8;
+ return x | get8(src);
+}
+
+int
+get32(Tracker *src)
+{+ int x;
+ x = get16(src) << 16;
+ return x | get16(src);
+}
+
+int
+getvar(Tracker *src)
+{+ int k, x;
+
+ x = get8(src);
+ k = x & 0x7F;
+ while(x & 0x80){+ k <<= 7;
+ x = get8(src);
+ k |= x & 0x7F;
+ }
+ return k;
+}
+
+int
+peekvar(Tracker *src)
+{+ uchar *p;
+ int v;
+
+ p = src->data;
+ v = getvar(src);
+ src->data = p;
+ return v;
+}
+
+void
+skip(Tracker *src, int x)
+{+ if(x) do
+ get8(src);
+ while(--x);
+}
+
+uvlong
+tconv(int n)
+{+ uvlong v;
+
+ v = n;
+ v *= tempo;
+ v *= SAMPLE;
+ v /= div;
+ v /= 1000000;
+ return v;
+}
+
+void
+run(uvlong n)
+{+ int samp, j, k, l, no[128];
+ uchar *s;
+ int t, f;
+ short u;
+ Tracker *x;
+
+ samp = n - T;
+ if(samp <= 0)
+ return;
+ memset(no, 0, sizeof no);
+ for(x = tr; x < tr + ntrack; x++){+ if(x->ended)
+ continue;
+ for(j = 0; j < 16; j++)
+ for(k = 0; k < 128; k++)
+ no[k] += x->notes[j][k];
+ }
+ s = emallocz(samp * 4);
+ for(l = 0; l < samp; l++){+ t = 0;
+ for(k = 0; k < 128; k++){+ f = (T % freq[k]) >= freq[k]/2 ? 1 : 0;
+ t += f * no[k];
+ }
+ u = t*10;
+ s[4 * l] = s[4 * l + 2] = u;
+ s[4 * l + 1] = s[4 * l + 3] = u >> 8;
+ T++;
+ }
+ write(ofd, s, samp * 4);
+ free(s);
+}
+
+void
+readevent(Tracker *src)
+{+ uvlong l;
+ int n,t;
+
+ l = tconv(getvar(src));
+ run(src->t += l);
+ t = get8(src);
+ if((t & 0x80) == 0){+ src->data--;
+ t = src->cmd;
+ if((t & 0x80) == 0)
+ sysfatal("invalid midi");+ }else
+ src->cmd = t;
+ switch(t >> 4){+ case 0x8:
+ n = get8(src);
+ get8(src);
+ src->notes[t & 15][n] = 0;
+ break;
+ case 0x9:
+ n = get8(src);
+ src->notes[t & 15][n] = get8(src);
+ break;
+ case 0xB:
+ get16(src);
+ break;
+ case 0xC:
+ get8(src);
+ break;
+ case 0xF:
+ t = get8(src);
+ n = get8(src);
+ switch(t){+ case 0x2F:
+ src->ended = 1;
+ break;
+ case 0x51:
+ tempo = get16(src) << 8;
+ tempo |= get8(src);
+ break;
+ case 5:
+ write(1, src->data, n);
+ skip(src, n);
+ break;
+ default:
+ print("unknown meta event type %.2x\n", t);+ case 3: case 1: case 2: case 0x58: case 0x59: case 0x21:
+ skip(src, n);
+ }
+ break;
+ default:
+ sysfatal("unknown event type %x", t>>4);+ }
+}
+
+void
+main(int argc, char **argv)
+{+ int i, size;
+ uvlong t, mint;
+ Tracker *x, *minx;
+
+ if(argc != 2)
+ sysfatal("invalid arguments");+ fd = open(argv[1], OREAD);
+ if(fd < 0)
+ sysfatal("open: %r");+ ofd = open("/dev/audio", OWRITE);+ if(ofd < 0)
+ sysfatal("ofd: %r");+ if(get32(nil) != 0x4D546864 || get32(nil) != 6)
+ sysfatal("invalid file header");+ get16(nil);
+ ntrack = get16(nil);
+ div = get16(nil);
+ tr = emallocz(ntrack * sizeof(*tr));
+ for(i = 0; i < ntrack; i++){+ if(get32(nil) != 0x4D54726B)
+ sysfatal("invalid track header");+ size = get32(nil);
+ tr[i].data = emallocz(size);
+ read(fd, tr[i].data, size);
+ }
+ for(i = 0; i < 128; i++)
+ freq[i] = SAMPLE / (440 * pow(1.05946, i - 69));
+ for(;;){+ minx = nil;
+ mint = 0;
+ for(x = tr; x < tr + ntrack; x++){+ if(x->ended)
+ continue;
+ t = tconv(peekvar(x)) + x->t;
+ if(t < mint || minx == nil){+ mint = t;
+ minx = x;
+ }
+ }
+ if(minx == nil)
+ exits(nil);
+ readevent(minx);
+ }
+}
--- a/sys/src/games/mkfile
+++ b/sys/src/games/mkfile
@@ -12,6 +12,7 @@
glendy\
packet\
mandel\
+ midi\
OFILES=
HFILES=