ref: 8a4a2dea70aa77475a50968f4c5bd6cdab5d2fb1
dir: /sys/src/games/vocdec.c/
#include <u.h> #include <libc.h> #define GET16(p) ((u16int)(p)[0] | (u16int)(p)[1]<<8) #define GET24(p) ((u32int)(p)[0] | (u32int)(p)[1]<<8 | (u32int)(p)[2]<<16) #define GET32(p) ((u32int)(p)[0] | (u32int)(p)[1]<<8 | (u32int)(p)[2]<<16 | (u32int)(p)[3]<<24) typedef struct Block Block; struct Block { uchar type; uint size; uint freq; uint codec; uchar chan; uint bits; }; char* codec(int c) { switch(c){ case 0x00: return "u8"; case 0x04: return "s16"; case 0x06: return "µ8"; case 0x07: return "a8"; default: sysfatal("unsupported"); } } void usage(void) { fprint(2, "usage: %s", argv0); exits("usage"); } Block b; void main(int argc, char **argv) { uchar buf[8192]; char fmt[32], size[32]; ushort chksum, ver; int n; ARGBEGIN{ default: usage(); break; }ARGEND; if(readn(0, buf, 20+2+2+2) != 20+2+2+2 || memcmp(buf, "Creative Voice File\x1a", 20) != 0) sysfatal("not a voc file"); ver = GET16(buf+20+2); chksum = GET16(buf+20+2+2); if(~ver + 0x1234 != chksum) sysfatal("invalid checksum"); for(;;){ if(readn(0, buf, 4) != 4) break; b.type = buf[0]; b.size = GET24(buf+1); switch(b.type){ case 0: exits(nil); case 1: if(readn(0, buf, 2) != 2) sysfatal("truncated block"); b.codec = buf[0]; b.freq = 1000000 / (256 - buf[1]); b.chan = 1; b.size -= 2; break; case 2: if(b.freq == 0) sysfatal("block 2 without defined codec"); break; case 9: if(readn(0, buf, 4+1+1+2+4) != 4+1+1+2+4) sysfatal("truncated block"); b.freq = GET32(buf); b.bits = buf[4]; b.chan = buf[5]; b.codec = buf[6]; b.size -= 4+1+1+2+4; break; default: while(b.size != 0){ n = b.size; if(n > sizeof buf) n = sizeof buf; if(read(0, buf, n) <= 0) sysfatal("truncated block"); b.size -= n; } break; } snprint(fmt, sizeof fmt, "%sc%dr%d", codec(b.codec), b.chan, b.freq); snprint(size, sizeof size, "%d", b.size); if(fork() == 0){ execl("/bin/audio/pcmconv", "pcmconv", "-i", fmt, "-l", size, nil); sysfatal("exec: %r"); } waitpid(); } exits(nil); }