add gzip, bzip2
'
diff --git a/src/cmd/gzip/unzip.c b/src/cmd/gzip/unzip.c
new file mode 100644
index 0000000..2f7888d
--- /dev/null
+++ b/src/cmd/gzip/unzip.c
@@ -0,0 +1,740 @@
+#include <u.h>
+#include <libc.h>
+#include <bio.h>
+#include <flate.h>
+#include "zip.h"
+
+enum
+{
+	BufSize	= 4096
+};
+
+static	int	cheader(Biobuf *bin, ZipHead *zh);
+static	int	copyout(int ofd, Biobuf *bin, long len);
+static	int	crcwrite(void *ofd, void *buf, int n);
+static	int	findCDir(Biobuf *bin, char *file);
+static	int	get1(Biobuf *b);
+static	int	get2(Biobuf *b);
+static	ulong	get4(Biobuf *b);
+static	char	*getname(Biobuf *b, int len);
+static	int	header(Biobuf *bin, ZipHead *zh);
+static	long	msdos2time(int time, int date);
+static	int	sunzip(Biobuf *bin);
+static	int	sunztable(Biobuf *bin);
+static	void	trailer(Biobuf *bin, ZipHead *zh);
+static	int	unzip(Biobuf *bin, char *file);
+static	int	unzipEntry(Biobuf *bin, ZipHead *czh);
+static	int	unztable(Biobuf *bin, char *file);
+static	int	wantFile(char *file);
+
+static	void	*emalloc(ulong);
+static	void	error(char*, ...);
+/* #pragma	varargck	argpos	error	1 */
+
+static	Biobuf	bin;
+static	ulong	crc;
+static	ulong	*crctab;
+static	int	debug;
+static	char	*delfile;
+static	int	lower;
+static	int	nwant;
+static	ulong	rlen;
+static	int	settimes;
+static	int	stdout;
+static	int	verbose;
+static	char	**want;
+static	int	wbad;
+static	ulong	wlen;
+static	jmp_buf	zjmp;
+
+static void
+usage(void)
+{
+	fprint(2, "usage: unzip [-tsv] [-f zipfile] [file ...]\n");
+	exits("usage");
+}
+
+void
+main(int argc, char *argv[])
+{
+	char *zfile;
+	int fd, ok, table, stream;
+
+	table = 0;
+	stream = 0;
+	zfile = nil;
+	ARGBEGIN{
+	case 'D':
+		debug++;
+		break;
+	case 'c':
+		stdout++;
+		break;
+	case 'i':
+		lower++;
+		break;
+	case 'f':
+		zfile = ARGF();
+		if(zfile == nil)
+			usage();
+		break;
+	case 's':
+		stream++;
+		break;
+	case 't':
+		table++;
+		break;
+	case 'T':
+		settimes++;
+		break;
+	case 'v':
+		verbose++;
+		break;
+	default:
+		usage();
+		break;
+	}ARGEND
+
+	nwant = argc;
+	want = argv;
+
+	crctab = mkcrctab(ZCrcPoly);
+	ok = inflateinit();
+	if(ok != FlateOk)
+		sysfatal("inflateinit failed: %s\n", flateerr(ok));
+
+	if(zfile == nil){
+		Binit(&bin, 0, OREAD);
+		zfile = "<stdin>";
+	}else{
+		fd = open(zfile, OREAD);
+		if(fd < 0)
+			sysfatal("can't open %s: %r", zfile);
+		Binit(&bin, fd, OREAD);
+	}
+
+	if(table){
+		if(stream)
+			ok = sunztable(&bin);
+		else
+			ok = unztable(&bin, zfile);
+	}else{
+		if(stream)
+			ok = sunzip(&bin);
+		else
+			ok = unzip(&bin, zfile);
+	}
+
+	exits(ok ? nil: "errors");
+}
+
+/*
+ * print the table of contents from the "central directory structure"
+ */
+static int
+unztable(Biobuf *bin, char *file)
+{
+	ZipHead zh;
+	int entries;
+
+	entries = findCDir(bin, file);
+	if(entries < 0)
+		return 0;
+
+	if(verbose > 1)
+		print("%d items in the archive\n", entries);
+	while(entries-- > 0){
+		if(setjmp(zjmp)){
+			free(zh.file);
+			return 0;
+		}
+
+		memset(&zh, 0, sizeof(zh));
+		if(!cheader(bin, &zh))
+			return 1;
+
+		if(wantFile(zh.file)){
+			if(verbose)
+				print("%-32s %10lud %s", zh.file, zh.uncsize, ctime(msdos2time(zh.modtime, zh.moddate)));
+			else
+				print("%s\n", zh.file);
+
+			if(verbose > 1){
+				print("\tmade by os %d vers %d.%d\n", zh.madeos, zh.madevers/10, zh.madevers % 10);
+				print("\textract by os %d vers %d.%d\n", zh.extos, zh.extvers/10, zh.extvers % 10);
+				print("\tflags %x\n", zh.flags);
+				print("\tmethod %d\n", zh.meth);
+				print("\tmod time %d\n", zh.modtime);
+				print("\tmod date %d\n", zh.moddate);
+				print("\tcrc %lux\n", zh.crc);
+				print("\tcompressed size %lud\n", zh.csize);
+				print("\tuncompressed size %lud\n", zh.uncsize);
+				print("\tinternal attributes %ux\n", zh.iattr);
+				print("\texternal attributes %lux\n", zh.eattr);
+				print("\tstarts at %ld\n", zh.off);
+			}
+		}
+
+		free(zh.file);
+		zh.file = nil;
+	}
+
+	return 1;
+}
+
+/*
+ * print the "local file header" table of contents
+ */
+static int
+sunztable(Biobuf *bin)
+{
+	ZipHead zh;
+	vlong off;
+	ulong hcrc, hcsize, huncsize;
+	int ok, err;
+
+	ok = 1;
+	for(;;){
+		if(setjmp(zjmp)){
+			free(zh.file);
+			return 0;
+		}
+
+		memset(&zh, 0, sizeof(zh));
+		if(!header(bin, &zh))
+			return ok;
+
+		hcrc = zh.crc;
+		hcsize = zh.csize;
+		huncsize = zh.uncsize;
+
+		wlen = 0;
+		rlen = 0;
+		crc = 0;
+		wbad = 0;
+
+		if(zh.meth == 0){
+			if(!copyout(-1, bin, zh.csize))
+				error("reading data for %s failed: %r", zh.file);
+		}else if(zh.meth == 8){
+			off = Boffset(bin);
+			err = inflate((void*)-1, crcwrite, bin, (int(*)(void*))Bgetc);
+			if(err != FlateOk)
+				error("inflate %s failed: %s", zh.file, flateerr(err));
+			rlen = Boffset(bin) - off;
+		}else
+			error("can't handle compression method %d for %s", zh.meth, zh.file);
+
+		trailer(bin, &zh);
+
+		if(wantFile(zh.file)){
+			if(verbose)
+				print("%-32s %10lud %s", zh.file, zh.uncsize, ctime(msdos2time(zh.modtime, zh.moddate)));
+			else
+				print("%s\n", zh.file);
+
+			if(verbose > 1){
+				print("\textract by os %d vers %d.%d\n", zh.extos, zh.extvers / 10, zh.extvers % 10);
+				print("\tflags %x\n", zh.flags);
+				print("\tmethod %d\n", zh.meth);
+				print("\tmod time %d\n", zh.modtime);
+				print("\tmod date %d\n", zh.moddate);
+				print("\tcrc %lux\n", zh.crc);
+				print("\tcompressed size %lud\n", zh.csize);
+				print("\tuncompressed size %lud\n", zh.uncsize);
+				if((zh.flags & ZTrailInfo) && (hcrc || hcsize || huncsize)){
+					print("\theader crc %lux\n", zh.crc);
+					print("\theader compressed size %lud\n", zh.csize);
+					print("\theader uncompressed size %lud\n", zh.uncsize);
+				}
+			}
+		}
+
+		if(zh.crc != crc)
+			error("crc mismatch for %s", zh.file);
+		if(zh.uncsize != wlen)
+			error("output size mismatch for %s", zh.file);
+		if(zh.csize != rlen)
+			error("input size mismatch for %s", zh.file);
+
+
+		free(zh.file);
+		zh.file = nil;
+	}
+
+	return ok;
+}
+
+/*
+ * extract files using the info in the central directory structure
+ */
+static int
+unzip(Biobuf *bin, char *file)
+{
+	ZipHead zh;
+	vlong off;
+	int ok, eok, entries;
+
+	entries = findCDir(bin, file);
+	if(entries < 0)
+		return 0;
+
+	ok = 1;
+	while(entries-- > 0){
+		if(setjmp(zjmp)){
+			free(zh.file);
+			return 0;
+		}
+		memset(&zh, 0, sizeof(zh));
+		if(!cheader(bin, &zh))
+			return ok;
+
+
+		off = Boffset(bin);
+		if(wantFile(zh.file)){
+			if(Bseek(bin, zh.off, 0) < 0){
+				fprint(2, "unzip: can't seek to start of %s, skipping\n", zh.file);
+				ok = 0;
+			}else{
+				eok = unzipEntry(bin, &zh);
+				if(eok <= 0){
+					fprint(2, "unzip: skipping %s\n", zh.file);
+					ok = 0;
+				}
+			}
+		}
+
+		free(zh.file);
+		zh.file = nil;
+
+		if(Bseek(bin, off, 0) < 0){
+			fprint(2, "unzip: can't seek to start of next entry, terminating extraction\n");
+			return 0;
+		}
+	}
+
+	return ok;
+}
+
+/*
+ * extract files using the info the "local file headers"
+ */
+static int
+sunzip(Biobuf *bin)
+{
+	int eok;
+
+	for(;;){
+		eok = unzipEntry(bin, nil);
+		if(eok == 0)
+			return 1;
+		if(eok < 0)
+			return 0;
+	}
+
+	return 1;
+}
+
+/*
+ * extracts a single entry from a zip file
+ * czh is the optional corresponding central directory entry
+ */
+static int
+unzipEntry(Biobuf *bin, ZipHead *czh)
+{
+	Dir *d;
+	ZipHead zh;
+	char *p;
+	vlong off;
+	int fd, isdir, ok, err;
+
+	zh.file = nil;
+	if(setjmp(zjmp)){
+		delfile = nil;
+		free(zh.file);
+		return -1;
+	}
+
+	memset(&zh, 0, sizeof(zh));
+	if(!header(bin, &zh))
+		return 0;
+
+	ok = 1;
+	isdir = 0;
+
+	fd = -1;
+	if(wantFile(zh.file)){
+		if(verbose)
+			fprint(2, "extracting %s\n", zh.file);
+
+		if(czh != nil && czh->extos == ZDos){
+			isdir = czh->eattr & ZDDir;
+			if(isdir && zh.uncsize != 0)
+				fprint(2, "unzip: ignoring directory data for %s\n", zh.file);
+		}
+		if(zh.meth == 0 && zh.uncsize == 0){
+			p = strchr(zh.file, '\0');
+			if(p > zh.file && p[-1] == '/')
+				isdir = 1;
+		}
+
+		if(stdout){
+			if(ok && !isdir)
+				fd = 1;
+		}else if(isdir){
+			fd = create(zh.file, OREAD, DMDIR | 0775);
+			if(fd < 0){
+				d = dirstat(zh.file);
+				if(d == nil || (d->mode & DMDIR) != DMDIR){
+					fprint(2, "unzip: can't create directory %s: %r\n", zh.file);
+					ok = 0;
+				}
+				free(d);
+			}
+		}else if(ok){
+			fd = create(zh.file, OWRITE, 0664);
+			if(fd < 0){
+				fprint(2, "unzip: can't create %s: %r\n", zh.file);
+				ok = 0;
+			}else
+				delfile = zh.file;
+		}
+	}
+
+	wlen = 0;
+	rlen = 0;
+	crc = 0;
+	wbad = 0;
+
+	if(zh.meth == 0){
+		if(!copyout(fd, bin, zh.csize))
+			error("copying data for %s failed: %r", zh.file);
+	}else if(zh.meth == 8){
+		off = Boffset(bin);
+		err = inflate((void*)fd, crcwrite, bin, (int(*)(void*))Bgetc);
+		if(err != FlateOk)
+			error("inflate failed: %s", flateerr(err));
+		rlen = Boffset(bin) - off;
+	}else
+		error("can't handle compression method %d for %s", zh.meth, zh.file);
+
+	trailer(bin, &zh);
+
+	if(zh.crc != crc)
+		error("crc mismatch for %s", zh.file);
+	if(zh.uncsize != wlen)
+		error("output size mismatch for %s", zh.file);
+	if(zh.csize != rlen)
+		error("input size mismatch for %s", zh.file);
+
+	delfile = nil;
+	free(zh.file);
+
+	if(fd >= 0 && !stdout){
+		if(settimes){
+			d = dirfstat(fd);
+			if(d != nil){
+				d->mtime = msdos2time(zh.modtime, zh.moddate);
+				if(d->mtime)
+					dirfwstat(fd, d);
+			}
+		}
+		close(fd);
+	}
+
+	return ok;
+}
+
+static int
+wantFile(char *file)
+{
+	int i, n;
+
+	if(nwant == 0)
+		return 1;
+	for(i = 0; i < nwant; i++){
+		if(strcmp(want[i], file) == 0)
+			return 1;
+		n = strlen(want[i]);
+		if(strncmp(want[i], file, n) == 0 && file[n] == '/')
+			return 1;
+	}
+	return 0;
+}
+
+/*
+ * find the start of the central directory
+ * returns the number of entries in the directory,
+ * or -1 if there was an error
+ */
+static int
+findCDir(Biobuf *bin, char *file)
+{
+	vlong ecoff;
+	long off, size;
+	int entries, zclen, dn, ds, de;
+
+	ecoff = Bseek(bin, -ZECHeadSize, 2);
+	if(ecoff < 0){
+		fprint(2, "unzip: can't seek to contents of %s; try adding -s\n", file);
+		return -1;
+	}
+	if(setjmp(zjmp))
+		return -1;
+
+	if(get4(bin) != ZECHeader){
+		fprint(2, "unzip: bad magic number for contents of %s\n", file);
+		return -1;
+	}
+	dn = get2(bin);
+	ds = get2(bin);
+	de = get2(bin);
+	entries = get2(bin);
+	size = get4(bin);
+	off = get4(bin);
+	zclen = get2(bin);
+	while(zclen-- > 0)
+		get1(bin);
+
+	if(verbose > 1){
+		print("table starts at %ld for %ld bytes\n", off, size);
+		if(ecoff - size != off)
+			print("\ttable should start at %lld-%ld=%lld\n", ecoff, size, ecoff-size);
+		if(dn || ds || de != entries)
+			print("\tcurrent disk=%d start disk=%d table entries on this disk=%d\n", dn, ds, de);
+	}
+
+	if(Bseek(bin, off, 0) != off){
+		fprint(2, "unzip: can't seek to start of contents of %s\n", file);
+		return -1;
+	}
+
+	return entries;
+}
+
+static int
+cheader(Biobuf *bin, ZipHead *zh)
+{
+	ulong v;
+	int flen, xlen, fclen;
+
+	v = get4(bin);
+	if(v != ZCHeader){
+		if(v == ZECHeader)
+			return 0;
+		error("bad magic number %lux", v);
+	}
+	zh->madevers = get1(bin);
+	zh->madeos = get1(bin);
+	zh->extvers = get1(bin);
+	zh->extos = get1(bin);
+	zh->flags = get2(bin);
+	zh->meth = get2(bin);
+	zh->modtime = get2(bin);
+	zh->moddate = get2(bin);
+	zh->crc = get4(bin);
+	zh->csize = get4(bin);
+	zh->uncsize = get4(bin);
+	flen = get2(bin);
+	xlen = get2(bin);
+	fclen = get2(bin);
+	get2(bin);		/* disk number start */
+	zh->iattr = get2(bin);
+	zh->eattr = get4(bin);
+	zh->off = get4(bin);
+
+	zh->file = getname(bin, flen);
+
+	while(xlen-- > 0)
+		get1(bin);
+
+	while(fclen-- > 0)
+		get1(bin);
+
+	return 1;
+}
+
+static int
+header(Biobuf *bin, ZipHead *zh)
+{
+	ulong v;
+	int flen, xlen;
+
+	v = get4(bin);
+	if(v != ZHeader){
+		if(v == ZCHeader)
+			return 0;
+		error("bad magic number %lux at %lld", v, Boffset(bin)-4);
+	}
+	zh->extvers = get1(bin);
+	zh->extos = get1(bin);
+	zh->flags = get2(bin);
+	zh->meth = get2(bin);
+	zh->modtime = get2(bin);
+	zh->moddate = get2(bin);
+	zh->crc = get4(bin);
+	zh->csize = get4(bin);
+	zh->uncsize = get4(bin);
+	flen = get2(bin);
+	xlen = get2(bin);
+
+	zh->file = getname(bin, flen);
+
+	while(xlen-- > 0)
+		get1(bin);
+
+	return 1;
+}
+
+static void
+trailer(Biobuf *bin, ZipHead *zh)
+{
+	if(zh->flags & ZTrailInfo){
+		zh->crc = get4(bin);
+		zh->csize = get4(bin);
+		zh->uncsize = get4(bin);
+	}
+}
+
+static char*
+getname(Biobuf *bin, int len)
+{
+	char *s;
+	int i, c;
+
+	s = emalloc(len + 1);
+	for(i = 0; i < len; i++){
+		c = get1(bin);
+		if(lower)
+			c = tolower(c);
+		s[i] = c;
+	}
+	s[i] = '\0';
+	return s;
+}
+
+static int
+crcwrite(void *out, void *buf, int n)
+{
+	int fd, nw;
+
+	wlen += n;
+	crc = blockcrc(crctab, crc, buf, n);
+	fd = (int)out;
+	if(fd < 0)
+		return n;
+	nw = write(fd, buf, n);
+	if(nw != n)
+		wbad = 1;
+	return nw;
+}
+
+static int
+copyout(int ofd, Biobuf *bin, long len)
+{
+	char buf[BufSize];
+	int n;
+
+	for(; len > 0; len -= n){
+		n = len;
+		if(n > BufSize)
+			n = BufSize;
+		n = Bread(bin, buf, n);
+		if(n <= 0)
+			return 0;
+		rlen += n;
+		if(crcwrite((void*)ofd, buf, n) != n)
+			return 0;
+	}
+	return 1;
+}
+
+static ulong
+get4(Biobuf *b)
+{
+	ulong v;
+	int i, c;
+
+	v = 0;
+	for(i = 0; i < 4; i++){
+		c = Bgetc(b);
+		if(c < 0)
+			error("unexpected eof reading file information");
+		v |= c << (i * 8);
+	}
+	return v;
+}
+
+static int
+get2(Biobuf *b)
+{
+	int i, c, v;
+
+	v = 0;
+	for(i = 0; i < 2; i++){
+		c = Bgetc(b);
+		if(c < 0)
+			error("unexpected eof reading file information");
+		v |= c << (i * 8);
+	}
+	return v;
+}
+
+static int
+get1(Biobuf *b)
+{
+	int c;
+
+	c = Bgetc(b);
+	if(c < 0)
+		error("unexpected eof reading file information");
+	return c;
+}
+
+static long
+msdos2time(int time, int date)
+{
+	Tm tm;
+
+	tm.hour = time >> 11;
+	tm.min = (time >> 5) & 63;
+	tm.sec = (time & 31) << 1;
+	tm.year = 80 + (date >> 9);
+	tm.mon = ((date >> 5) & 15) - 1;
+	tm.mday = date & 31;
+	tm.zone[0] = '\0';
+	tm.yday = 0;
+
+	return tm2sec(&tm);
+}
+
+static void*
+emalloc(ulong n)
+{
+	void *p;
+
+	p = malloc(n);
+	if(p == nil)
+		sysfatal("out of memory");
+	return p;
+}
+
+static void
+error(char *fmt, ...)
+{
+	va_list arg;
+
+	fprint(2, "unzip: ");
+	va_start(arg, fmt);
+	vfprint(2, fmt, arg);
+	va_end(arg);
+	fprint(2, "\n");
+
+	if(delfile != nil){
+		fprint(2, "unzip: removing output file %s\n", delfile);
+		remove(delfile);
+		delfile = nil;
+	}
+
+	longjmp(zjmp, 1);
+}