/* pump - copy through circular buffer */#include <u.h>#include <libc.h> uchar*	buf; Lock	arithlock;	/* protect 64-bit accesses: unlikely to be atomic */uvlong	nin;uvlong	nout; ulong	kilo;ulong	max;long	ssize;vlong	tsize;int	dsize;int	done;int	ibsize;int	obsize;int	verb;vlong	off; void	doinput(int);void	dooutput(int); static voidusage(void){	fprint(2, "usage: pump [-b iando] [-d sleeptime] [-f ofile] "		"[-i ireadsize]\n\t[-k KB-buffer] [-o owritesize] "		"[-s start-KB] [-S seek-offset]\n\t[-t mins] [files]\n");	exits("usage");} voidmain(int argc, char *argv[]){	int i, f, fo;	char *file; 	kilo = 5000;	obsize = ibsize = 8*1024;	dsize = 0;	fo = 1;	off = 0; 	ARGBEGIN {	default:		usage();	case 'b':		obsize = ibsize = atoi(EARGF(usage()));		break;	case 'd':		dsize = atoi(EARGF(usage()));		break;	case 'f':		file = EARGF(usage());		fo = create(file, 1, 0666);		if(fo < 0)			sysfatal("can't create %s: %r", file);		break;	case 'i':		ibsize = atoi(EARGF(usage()));		break;	case 'k':		kilo = atoi(EARGF(usage()));		break;	case 'o':		obsize = atoi(EARGF(usage()));		break;	case 's':		ssize = atoi(EARGF(usage()));		if(ssize <= 0)			ssize = 800;		ssize <<= 10;		break;	case 'S':		off = atoll(EARGF(usage()));		if(off < 0)			sysfatal("seek offset %lld must be non-negative", off);		break;	case 't':		tsize = atoll(EARGF(usage()));		tsize *= 10584000;		/* minutes */		break;	} ARGEND	kilo <<= 10; 	buf = malloc(kilo);	if(buf == nil)		sysfatal("no memory: %r");	nin = 0;	nout = 0;	done = 0;	max = 0; 	switch(rfork(RFPROC|RFNOWAIT|RFNAMEG|RFMEM)) {	default:		dooutput(fo);		break;	case 0:		for(i=0; i<argc; i++) {			f = open(argv[i], OREAD);			if(f < 0) {				fprint(2, "%s: can't open %s: %r\n",					argv0, argv[i]);				break;			}			doinput(f);			close(f);		}		if(argc == 0)			doinput(0);		break;	case -1:		fprint(2, "%s: fork failed: %r\n", argv0);		break;	}	done = 1;	exits(0);} /* call with arithlock held */static intsleepunlocked(long ms){	int r; 	unlock(&arithlock);	r = sleep(ms);	lock(&arithlock);	return r;} voiddooutput(int f){	long n, l, c; 	seek(f, off, 0);	lock(&arithlock);	for (;;) {		n = nin - nout;		if(n == 0) {			if(done)				break;			sleepunlocked(dsize);			continue;		}		if(verb && n > max) {			fprint(2, "n = %ld\n", n);			max = n;		}		l = nout % kilo;		unlock(&arithlock); 		if(kilo-l < n)			n = kilo-l;		if(n > obsize)			n = obsize;		c = write(f, buf+l, n); 		lock(&arithlock);		if(c != n) {			fprint(2, "%s: write error at offset %,lld: %r\n",				argv0, seek(f, 0, 1));			break;		}		nout += c;		if(tsize && nout > tsize) {			fprint(2, "%s: time limit exceeded\n", argv0);			break;		}	}	unlock(&arithlock);} voiddoinput(int f){	long n, l, c, xnin; 	seek(f, off, 0);	lock(&arithlock);	if(ssize > 0) {		for (xnin = 0; xnin < ssize && !done; xnin += c) {			n = kilo - (xnin - nout);			if(n == 0)				break;			unlock(&arithlock); 			l = xnin % kilo;			if(kilo-l < n)				n = kilo-l;			if(n > ibsize)				n = ibsize;			c = read(f, buf+l, n); 			lock(&arithlock);			if(c <= 0) {				if(c < 0)					fprint(2, "%s: read error: %r\n", argv0);				break;			}		}		nin = xnin;	}	while(!done) {		n = kilo - (nin - nout);		if(n == 0) {			sleepunlocked(0);			continue;		}		l = nin % kilo;		unlock(&arithlock); 		if(kilo-l < n)			n = kilo-l;		if(n > ibsize)			n = ibsize;		c = read(f, buf+l, n); 		lock(&arithlock);		if(c <= 0) {			if(c < 0)				fprint(2, "%s: read error: %r\n", argv0);			break;		}		nin += c;	}	unlock(&arithlock);}