Add support for uncompressing pack(1)'ed files. Pack(1) is a program found

in some commercial Unix systems, which utilizes Huffman minimum redundancy
code tree to compress files.  This implementation supports the "new" pack
format only, just like GNU gzip did.

Thanks for oliver@'s archive set which I can test against, and Mingyan Guo
for providing helpful review of my code.

PR:		bin/109567
MFC after:	1 month

1 files changed, 37 insertions, 1 deletions

diff --git a/usr.bin/gzip/gzip.c b/usr.bin/gzip/gzip.c
index e33acc8..bdff534 100644
--- a/usr.bin/gzip/gzip.c
+++ b/usr.bin/gzip/gzip.c
@@ -79,6 +79,9 @@ enum filetype {
 #ifndef NO_COMPRESS_SUPPORT
 	FT_Z,
 #endif
+#ifndef NO_PACK_SUPPORT
+	FT_PACK,
+#endif
 	FT_LAST,
 	FT_UNKNOWN
 };
@@ -95,6 +98,10 @@ enum filetype {
 #define Z_MAGIC		"\037\235"
 #endif
 
+#ifndef NO_PACK_SUPPORT
+#define PACK_MAGIC	"\037\036"
+#endif
+
 #define GZ_SUFFIX	".gz"
 
 #define BUFLEN		(64 * 1024)
@@ -143,7 +150,7 @@ static suffixes_t suffixes[] = {
 };
 #define NUM_SUFFIXES (sizeof suffixes / sizeof suffixes[0])
 
-static	const char	gzip_version[] = "FreeBSD gzip 20070711";
+static	const char	gzip_version[] = "FreeBSD gzip 20090621";
 
 #ifndef SMALL
 static	const char	gzip_copyright[] = \
@@ -248,6 +255,10 @@ static	FILE 	*zdopen(int);
 static	off_t	zuncompress(FILE *, FILE *, char *, size_t, off_t *);
 #endif
 
+#ifndef NO_PACK_SUPPORT
+static	off_t	unpack(int, int, char *, size_t, off_t *);
+#endif
+
 int main(int, char **p);
 
 #ifdef SMALL
@@ -1104,6 +1115,11 @@ file_gettype(u_char *buf)
 		return FT_Z;
 	else
 #endif
+#ifndef NO_PACK_SUPPORT
+	if (memcmp(buf, PACK_MAGIC, 2) == 0)
+		return FT_PACK;
+	else
+#endif
 		return FT_UNKNOWN;
 }
 
@@ -1458,6 +1474,17 @@ file_uncompress(char *file, char *outfile, size_t outsize)
 	} else
 #endif
 
+#ifndef NO_PACK_SUPPORT
+	if (method == FT_PACK) {
+		if (lflag) {
+			maybe_warnx("no -l with packed files");
+			goto lose;
+		}
+
+		size = unpack(fd, zfd, NULL, 0, NULL);
+	} else
+#endif
+
 #ifndef SMALL
 	if (method == FT_UNKNOWN) {
 		if (lflag) {
@@ -1651,6 +1678,12 @@ handle_stdin(void)
 		fclose(in);
 		break;
 #endif
+#ifndef NO_PACK_SUPPORT
+	case FT_PACK:
+		usize = unpack(STDIN_FILENO, STDOUT_FILENO,
+			       (char *)header1, sizeof header1, &gsize);
+		break;
+#endif
 	}
 
 #ifndef SMALL
@@ -2038,6 +2071,9 @@ display_version(void)
 #ifndef NO_COMPRESS_SUPPORT
 #include "zuncompress.c"
 #endif
+#ifndef NO_PACK_SUPPORT
+#include "unpack.c"
+#endif
 
 static ssize_t
 read_retry(int fd, void *buf, size_t sz)