#include <u.h>#include <libc.h>#include <bio.h>#include "ivf.h"#include "util.h" static intBu16le(Biobuf *b, u16int *o){	int x; 	x = Bgetc(b);	x |= Bgetc(b)<<8;	*o = x;	if(x < 0)		werrstr("failed to read 2 bytes"); 	return x < 0 ? -1 : 0;} static intBu32le(Biobuf *b, u32int *o){	int x, i; 	*o = 0;	for(i = 0; i < 4; *o |= x<<(i*8), i++){		if((x = Bgetc(b)) < 0){			werrstr("failed to read 4 bytes");			return -1;		}	} 	return 0;} static intBu64le(Biobuf *b, u64int *o){	int x, i; 	*o = 0;	for(i = 0; i < 8; *o |= (uvlong)x<<(i*8), i++){		if((x = Bgetc(b)) < 0){			werrstr("failed to read 8 bytes");			return -1;		}	} 	return 0;} intivfopen(Biobuf *v, IVF *ivf){	u16int hlen;	u8int b[6]; 	if(Bread(v, b, 6) != 6 || Bu16le(v, &hlen) < 0 ||	   hlen < 0x20 || memcmp(b, "DKIF", 4) != 0 ||	   Bread(v, b, 4) != 4){		werrstr("invalid header");		goto err;	}	memmove(ivf->type, b, 4);	ivf->v = v;	ivf->type[4] = 0;	ivf->ns₀ = Zns₀;	if(Bu16le(v, &ivf->w) < 0 ||	   Bu16le(v, &ivf->h) < 0 ||	   Bu32le(v, &ivf->tbdenum) < 0 ||	   Bu32le(v, &ivf->tbnum) < 0){		werrstr("invalid data");		goto err;	}	if(Bseek(v, hlen, 0) != hlen){		werrstr("broken stream");		goto err;	} 	return 0;err:	werrstr("ivfopen: %r");	return -1;} static u64intivfns(IVF *ivf, u64int ts){	return ts * (ivf->tbnum * 1000000000ULL / ivf->tbdenum);} intivfread(IVF *ivf, IVFrame *f){	u64int ts;	u32int sz;	int n; 	if(Bu32le(ivf->v, &sz) < 0 || Bu64le(ivf->v, &ts) < 0 || (int)sz < 0){		/* eof */		f->sz = 0;		return 0;	}	if(sz > f->bufsz){		f->bufsz = sz*2;		f->buf = erealloc(f->buf, sz*2);	}	if((n = Bread(ivf->v, f->buf, sz)) != sz){		werrstr("short read (%d < %d)", n, sz);		goto err;	}	if(ivf->ns₀ == Zns₀)		ivf->ns₀ = ivfns(ivf, ts);	f->sz = sz;	f->ns = ivfns(ivf, ts) - ivf->ns₀; 	return 0;err:	werrstr("ivfread: %r");	return -1;}