Index: gzip.c
===================================================================
RCS file: /cvsroot/src/usr.bin/gzip/gzip.c,v
retrieving revision 1.112
diff -p -u -u -r1.112 gzip.c
--- gzip.c	23 Aug 2017 13:04:17 -0000	1.112
+++ gzip.c	5 Dec 2017 03:01:27 -0000
@@ -143,6 +143,7 @@ static suffixes_t suffixes[] = {
 	SUFFIX("-gz",		""),
 	SUFFIX("-z",		""),
 	SUFFIX("_z",		""),
+	SUFFIX(".zz",		""),
 	SUFFIX(".taz",		".tar"),
 	SUFFIX(".tgz",		".tar"),
 #ifndef NO_BZIP2_SUPPORT
@@ -177,6 +178,7 @@ static	int	qflag;			/* quiet mode */
 static	int	rflag;			/* recursive mode */
 static	int	tflag;			/* test */
 static	int	vflag;			/* verbose mode */
+static	int	zflag;			/* zlib mode */
 static	sig_atomic_t print_info = 0;
 #else
 #define		qflag	0
@@ -278,6 +280,7 @@ static const struct option longopts[] = 
 	{ "test",		no_argument,		0,	't' },
 	{ "verbose",		no_argument,		0,	'v' },
 	{ "version",		no_argument,		0,	'V' },
+	{ "zlib",		no_argument,		0,	'z' },
 	{ "fast",		no_argument,		0,	'1' },
 	{ "best",		no_argument,		0,	'9' },
 #if 0
@@ -322,7 +325,7 @@ main(int argc, char **argv)
 #ifdef SMALL
 #define OPT_LIST "123456789cdhlV"
 #else
-#define OPT_LIST "123456789cdfhklNnqrS:tVv"
+#define OPT_LIST "123456789cdfhklNnqrS:tVvz"
 #endif
 
 	while ((ch = getopt_long(argc, argv, OPT_LIST, longopts, NULL)) != -1) {
@@ -386,6 +389,11 @@ main(int argc, char **argv)
 		case 'v':
 			vflag = 1;
 			break;
+		case 'z':
+			zflag = 1;
+			suffixes[0].zipped = ".zz";
+			suffixes[0].ziplen = strlen(suffixes[0].zipped);
+			break;
 #endif
 		default:
 			usage();
@@ -537,6 +545,16 @@ copy_done:
 		nargv[i++] = *(ac++);
 	nargv[i] = NULL;
 }
+
+static uLong gz_crc32(uLong, const Bytef *, uInt);
+/* use crc32 or alder32 depending on the file type */
+static uLong
+gz_crc32(uLong crc, const Bytef *buf, uInt len)
+{
+	if (zflag)
+		return adler32(crc, buf, len);
+	return crc32(crc, buf, len);
+}
 #endif
 
 /* compress input to output. Return bytes read, -1 on error */
@@ -576,20 +594,35 @@ gz_compress(int in, int out, off_t *gsiz
 		origname = "";
 	}
 
-	i = snprintf(outbufp, BUFLEN, "%c%c%c%c%c%c%c%c%c%c%s",
-		     GZIP_MAGIC0, GZIP_MAGIC1, Z_DEFLATED,
-		     *origname ? ORIG_NAME : 0,
-		     mtime & 0xff,
-		     (mtime >> 8) & 0xff,
-		     (mtime >> 16) & 0xff,
-		     (mtime >> 24) & 0xff,
-		     numflag == 1 ? 4 : numflag == 9 ? 2 : 0,
-		     OS_CODE, origname);
-	if (i >= BUFLEN)
-		/* this need PATH_MAX > BUFLEN ... */
-		maybe_err("snprintf");
-	if (*origname)
-		i++;
+	if (zflag == 0) {
+		i = snprintf(outbufp, BUFLEN, "%c%c%c%c%c%c%c%c%c%c%s",
+			     GZIP_MAGIC0, GZIP_MAGIC1, Z_DEFLATED,
+			     *origname ? ORIG_NAME : 0,
+			     mtime & 0xff,
+			     (mtime >> 8) & 0xff,
+			     (mtime >> 16) & 0xff,
+			     (mtime >> 24) & 0xff,
+			     numflag == 1 ? 4 : numflag == 9 ? 2 : 0,
+			     OS_CODE, origname);
+		if (i >= BUFLEN)
+			/* this need PATH_MAX > BUFLEN ... */
+			maybe_err("snprintf");
+		if (*origname)
+			i++;
+	} else {
+		outbufp[0] = 0x78;	/* 32K, deflate */
+		if (numflag == 1)
+			outbufp[1] = 0;
+		else if (numflag >= 9)
+			outbufp[1] = 3;
+		else if (numflag >= 5)
+			outbufp[1] = 1;
+		else
+			outbufp[1] = 2;
+		outbufp[1] <<= 6;
+		outbufp[1] += 31 - (((outbufp[0] << 8) + outbufp[1]) % 31);
+		i = 2;
+	}
 #endif
 
 	z.next_out = (unsigned char *)outbufp + i;
@@ -603,7 +636,7 @@ gz_compress(int in, int out, off_t *gsiz
 		goto out;
 	}
 
-	crc = crc32(0L, Z_NULL, 0);
+	crc = gz_crc32(0L, Z_NULL, 0);
 	for (;;) {
 		if (z.avail_out == 0) {
 			if (write_retry(out, outbufp, BUFLEN) != BUFLEN) {
@@ -628,7 +661,7 @@ gz_compress(int in, int out, off_t *gsiz
 				break;
 			infile_newdata(in_size);
 
-			crc = crc32(crc, (const Bytef *)inbufp, (unsigned)in_size);
+			crc = gz_crc32(crc, (const Bytef *)inbufp, (unsigned)in_size);
 			in_tot += in_size;
 			z.next_in = (unsigned char *)inbufp;
 			z.avail_in = in_size;
@@ -676,17 +709,28 @@ gz_compress(int in, int out, off_t *gsiz
 		goto out;
 	}
 
-	i = snprintf(outbufp, BUFLEN, "%c%c%c%c%c%c%c%c",
-		 (int)crc & 0xff,
-		 (int)(crc >> 8) & 0xff,
-		 (int)(crc >> 16) & 0xff,
-		 (int)(crc >> 24) & 0xff,
-		 (int)in_tot & 0xff,
-		 (int)(in_tot >> 8) & 0xff,
-		 (int)(in_tot >> 16) & 0xff,
-		 (int)(in_tot >> 24) & 0xff);
-	if (i != 8)
-		maybe_err("snprintf");
+	if (zflag == 0) {
+		i = snprintf(outbufp, BUFLEN, "%c%c%c%c%c%c%c%c",
+			 (int)crc & 0xff,
+			 (int)(crc >> 8) & 0xff,
+			 (int)(crc >> 16) & 0xff,
+			 (int)(crc >> 24) & 0xff,
+			 (int)in_tot & 0xff,
+			 (int)(in_tot >> 8) & 0xff,
+			 (int)(in_tot >> 16) & 0xff,
+			 (int)(in_tot >> 24) & 0xff);
+		if (i != 8)
+			maybe_err("snprintf");
+	} else {
+		i = snprintf(outbufp, BUFLEN, "%c%c%c%c",
+			 (int)crc & 0xff,
+			 (int)(crc >> 8) & 0xff,
+			 (int)(crc >> 16) & 0xff,
+			 (int)(crc >> 24) & 0xff);
+		if (i != 4)
+			maybe_err("snprintf");
+
+	}
 #if 0
 	if (in_tot > 0xffffffff)
 		maybe_warn("input file size >= 4GB cannot be saved");
@@ -815,7 +859,7 @@ gz_uncompress(int in, int out, char *pre
 			ADVANCE();
 			state++;
 			out_sub_tot = 0;
-			crc = crc32(0L, Z_NULL, 0);
+			crc = gz_crc32(0L, Z_NULL, 0);
 			break;
 
 		case GZSTATE_MAGIC1:
@@ -952,7 +996,7 @@ gz_uncompress(int in, int out, char *pre
 			wr = BUFLEN - z.avail_out;
 
 			if (wr != 0) {
-				crc = crc32(crc, (const Bytef *)outbufp, (unsigned)wr);
+				crc = gz_crc32(crc, (const Bytef *)outbufp, (unsigned)wr);
 				if (
 #ifndef SMALL
 				    /* don't write anything with -t */