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-rw-r--r--usr.bin/compress/Makefile12
-rw-r--r--usr.bin/compress/compress.1172
-rw-r--r--usr.bin/compress/compress.c444
-rw-r--r--usr.bin/compress/doc/NOTES139
-rw-r--r--usr.bin/compress/doc/README283
-rw-r--r--usr.bin/compress/doc/revision.log116
-rw-r--r--usr.bin/compress/zcat.sh37
-rw-r--r--usr.bin/compress/zopen.3139
-rw-r--r--usr.bin/compress/zopen.c740
9 files changed, 2082 insertions, 0 deletions
diff --git a/usr.bin/compress/Makefile b/usr.bin/compress/Makefile
new file mode 100644
index 000000000000..6a0683018cb9
--- /dev/null
+++ b/usr.bin/compress/Makefile
@@ -0,0 +1,12 @@
+# @(#)Makefile 8.2 (Berkeley) 4/17/94
+
+PROG= compress
+SRCS= compress.c zopen.c
+LINKS= ${BINDIR}/compress ${BINDIR}/uncompress
+MLINKS= compress.1 uncompress.1 compress.1 zcat.1
+
+afterinstall:
+ install -c -o ${BINOWN} -g ${BINGRP} -m ${BINMODE} \
+ ${.CURDIR}/zcat.sh ${DESTDIR}/usr/bin/zcat
+
+.include <bsd.prog.mk>
diff --git a/usr.bin/compress/compress.1 b/usr.bin/compress/compress.1
new file mode 100644
index 000000000000..74b7348cf928
--- /dev/null
+++ b/usr.bin/compress/compress.1
@@ -0,0 +1,172 @@
+.\" Copyright (c) 1986, 1990, 1993
+.\" The Regents of the University of California. All rights reserved.
+.\"
+.\" This code is derived from software contributed to Berkeley by
+.\" James A. Woods, derived from original work by Spencer Thomas
+.\" and Joseph Orost.
+.\"
+.\" Redistribution and use in source and binary forms, with or without
+.\" modification, are permitted provided that the following conditions
+.\" are met:
+.\" 1. Redistributions of source code must retain the above copyright
+.\" notice, this list of conditions and the following disclaimer.
+.\" 2. Redistributions in binary form must reproduce the above copyright
+.\" notice, this list of conditions and the following disclaimer in the
+.\" documentation and/or other materials provided with the distribution.
+.\" 3. All advertising materials mentioning features or use of this software
+.\" must display the following acknowledgement:
+.\" This product includes software developed by the University of
+.\" California, Berkeley and its contributors.
+.\" 4. Neither the name of the University nor the names of its contributors
+.\" may be used to endorse or promote products derived from this software
+.\" without specific prior written permission.
+.\"
+.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+.\" SUCH DAMAGE.
+.\"
+.\" @(#)compress.1 8.2 (Berkeley) 4/18/94
+.\"
+.Dd April 18, 1994
+.Dt COMPRESS 1
+.Os BSD 4.3
+.Sh NAME
+.Nm compress ,
+.Nm uncompress ,
+.Nm zcat
+.Nd compress and expand data
+.Sh SYNOPSIS
+.Nm compress
+.Op Fl cfv
+.Op Fl b Ar bits
+.Op Ar
+.Nm uncompress
+.Op Fl cfv
+.Op Ar
+.Nm zcat
+.Op Ar
+.Sh DESCRIPTION
+.Nm Compress
+reduces the size of the named files using adaptive Lempel-Ziv coding.
+Each
+.Ar file
+is renamed to the same name plus the extension
+.Dq .Z .
+As many of the modification time, access time, file flags, file mode,
+user ID, and group ID as allowed by permissions are retained in the
+new file.
+If compression would not reduce the size of a
+.Ar file ,
+the file is ignored.
+.Pp
+.Nm Uncompress
+restores the compressed files to their original form, renaming the
+files by deleting the
+.Dq .Z
+extension.
+.Pp
+.Nm Zcat
+is an alias for
+.Dq "uncompress -c" .
+.Pp
+If renaming the files would cause files to be overwritten and the standard
+input device is a terminal, the user is prompted (on the standard error
+output) for confirmation.
+If prompting is not possible or confirmation is not received, the files
+are not overwritten.
+.Pp
+If no files are specified, the standard input is compressed or uncompressed
+to the standard output.
+If either the input and output files are not regular files, the checks for
+reduction in size and file overwriting are not performed, the input file is
+not removed, and the attributes of the input file are not retained.
+.Pp
+The options are as follows:
+.Bl -tag -width Ds
+.It Fl b
+Specify the
+.Ar bits
+code limit (see below).
+.It Fl c
+Compressed or uncompressed output is written to the standard output.
+No files are modified.
+.It Fl f
+Force compression of
+.Ar file ,
+even if it is not actually reduced in size.
+Additionally, files are overwritten without prompting for confirmation.
+.It Fl v
+Print the percentage reduction of each file.
+.El
+.Pp
+.Nm Compress
+uses a modified Lempel-Ziv algorithm.
+Common substrings in the file are first replaced by 9-bit codes 257 and up.
+When code 512 is reached, the algorithm switches to 10-bit codes and
+continues to use more bits until the
+limit specified by the
+.Fl b
+flag is reached (the default is 16).
+.Ar Bits
+must be between 9 and 16.
+.Pp
+After the
+.Ar bits
+limit is reached,
+.Nm compress
+periodically checks the compression ratio.
+If it is increasing,
+.Nm compress
+continues to use the existing code dictionary.
+However, if the compression ratio decreases,
+.Nm compress
+discards the table of substrings and rebuilds it from scratch. This allows
+the algorithm to adapt to the next "block" of the file.
+.Pp
+The
+.Fl b
+flag is omitted for
+.Ar uncompress
+since the
+.Ar bits
+parameter specified during compression
+is encoded within the output, along with
+a magic number to ensure that neither decompression of random data nor
+recompression of compressed data is attempted.
+.Pp
+.ne 8
+The amount of compression obtained depends on the size of the
+input, the number of
+.Ar bits
+per code, and the distribution of common substrings.
+Typically, text such as source code or English is reduced by 50\-60%.
+Compression is generally much better than that achieved by Huffman
+coding (as used in the historical command pack), or adaptive Huffman
+coding (as used in the historical command compact), and takes less
+time to compute.
+.Pp
+The
+.Nm compress
+utility exits 0 on success, and >0 if an error occurs.
+.Sh SEE ALSO
+.Rs
+.%A Welch, Terry A.
+.%D June, 1984
+.%T "A Technique for High Performance Data Compression"
+.%J "IEEE Computer"
+.%V 17:6
+.%P pp. 8-19
+.Re
+.Sh HISTORY
+The
+.Nm
+command appeared in
+.Bx 4.3 .
diff --git a/usr.bin/compress/compress.c b/usr.bin/compress/compress.c
new file mode 100644
index 000000000000..d66d22433dcb
--- /dev/null
+++ b/usr.bin/compress/compress.c
@@ -0,0 +1,444 @@
+/*-
+ * Copyright (c) 1992, 1993
+ * The Regents of the University of California. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in the
+ * documentation and/or other materials provided with the distribution.
+ * 3. All advertising materials mentioning features or use of this software
+ * must display the following acknowledgement:
+ * This product includes software developed by the University of
+ * California, Berkeley and its contributors.
+ * 4. Neither the name of the University nor the names of its contributors
+ * may be used to endorse or promote products derived from this software
+ * without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+#ifndef lint
+static char copyright[] =
+"@(#) Copyright (c) 1992, 1993\n\
+ The Regents of the University of California. All rights reserved.\n";
+#endif /* not lint */
+
+#ifndef lint
+static char sccsid[] = "@(#)compress.c 8.2 (Berkeley) 1/7/94";
+#endif /* not lint */
+
+#include <sys/param.h>
+#include <sys/time.h>
+#include <sys/stat.h>
+
+#include <err.h>
+#include <errno.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+
+#ifdef __STDC__
+#include <stdarg.h>
+#else
+#include <varargs.h>
+#endif
+
+void compress __P((char *, char *, int));
+void cwarn __P((const char *, ...));
+void cwarnx __P((const char *, ...));
+void decompress __P((char *, char *, int));
+int permission __P((char *));
+void setfile __P((char *, struct stat *));
+void usage __P((int));
+
+int eval, force, verbose;
+
+int
+main(argc, argv)
+ int argc;
+ char *argv[];
+{
+ enum {COMPRESS, DECOMPRESS} style;
+ size_t len;
+ int bits, cat, ch;
+ char *p, newname[MAXPATHLEN];
+
+ if ((p = rindex(argv[0], '/')) == NULL)
+ p = argv[0];
+ else
+ ++p;
+ if (!strcmp(p, "uncompress"))
+ style = DECOMPRESS;
+ else if (!strcmp(p, "compress"))
+ style = COMPRESS;
+ else
+ errx(1, "unknown program name");
+
+ bits = cat = 0;
+ while ((ch = getopt(argc, argv, "b:cdfv")) != EOF)
+ switch(ch) {
+ case 'b':
+ bits = strtol(optarg, &p, 10);
+ if (*p)
+ errx(1, "illegal bit count -- %s", optarg);
+ break;
+ case 'c':
+ cat = 1;
+ break;
+ case 'd': /* Backward compatible. */
+ style = DECOMPRESS;
+ break;
+ case 'f':
+ force = 1;
+ break;
+ case 'v':
+ verbose = 1;
+ break;
+ case '?':
+ default:
+ usage(style == COMPRESS);
+ }
+ argc -= optind;
+ argv += optind;
+
+ if (argc == 0) {
+ switch(style) {
+ case COMPRESS:
+ (void)compress("/dev/stdin", "/dev/stdout", bits);
+ break;
+ case DECOMPRESS:
+ (void)decompress("/dev/stdin", "/dev/stdout", bits);
+ break;
+ }
+ exit (eval);
+ }
+
+ if (cat == 1 && argc > 1)
+ errx(1, "the -c option permits only a single file argument");
+
+ for (; *argv; ++argv)
+ switch(style) {
+ case COMPRESS:
+ if (cat) {
+ compress(*argv, "/dev/stdout", bits);
+ break;
+ }
+ if ((p = rindex(*argv, '.')) != NULL &&
+ !strcmp(p, ".Z")) {
+ cwarnx("%s: name already has trailing .Z",
+ *argv);
+ break;
+ }
+ len = strlen(*argv);
+ if (len > sizeof(newname) - 3) {
+ cwarnx("%s: name too long", *argv);
+ break;
+ }
+ memmove(newname, *argv, len);
+ newname[len] = '.';
+ newname[len + 1] = 'Z';
+ newname[len + 2] = '\0';
+ compress(*argv, newname, bits);
+ break;
+ case DECOMPRESS:
+ len = strlen(*argv);
+ if ((p = rindex(*argv, '.')) == NULL ||
+ strcmp(p, ".Z")) {
+ if (len > sizeof(newname) - 3) {
+ cwarnx("%s: name too long", *argv);
+ break;
+ }
+ memmove(newname, *argv, len);
+ newname[len] = '.';
+ newname[len + 1] = 'Z';
+ newname[len + 2] = '\0';
+ decompress(newname,
+ cat ? "/dev/stdout" : *argv, bits);
+ } else {
+ if (len - 2 > sizeof(newname) - 1) {
+ cwarnx("%s: name too long", *argv);
+ break;
+ }
+ memmove(newname, *argv, len - 2);
+ newname[len - 2] = '\0';
+ decompress(*argv,
+ cat ? "/dev/stdout" : newname, bits);
+ }
+ break;
+ }
+ exit (eval);
+}
+
+void
+compress(in, out, bits)
+ char *in, *out;
+ int bits;
+{
+ register int nr;
+ struct stat isb, sb;
+ FILE *ifp, *ofp;
+ int exists, isreg, oreg;
+ u_char buf[1024];
+
+ exists = !stat(out, &sb);
+ if (!force && exists && S_ISREG(sb.st_mode) && !permission(out))
+ return;
+ isreg = oreg = !exists || S_ISREG(sb.st_mode);
+
+ ifp = ofp = NULL;
+ if ((ifp = fopen(in, "r")) == NULL) {
+ cwarn("%s", in);
+ return;
+ }
+ if (stat(in, &isb)) { /* DON'T FSTAT! */
+ cwarn("%s", in);
+ goto err;
+ }
+ if (!S_ISREG(isb.st_mode))
+ isreg = 0;
+
+ if ((ofp = zopen(out, "w", bits)) == NULL) {
+ cwarn("%s", out);
+ goto err;
+ }
+ while ((nr = fread(buf, 1, sizeof(buf), ifp)) != 0)
+ if (fwrite(buf, 1, nr, ofp) != nr) {
+ cwarn("%s", out);
+ goto err;
+ }
+
+ if (ferror(ifp) || fclose(ifp)) {
+ cwarn("%s", in);
+ goto err;
+ }
+ ifp = NULL;
+
+ if (fclose(ofp)) {
+ cwarn("%s", out);
+ goto err;
+ }
+ ofp = NULL;
+
+ if (isreg) {
+ if (stat(out, &sb)) {
+ cwarn("%s", out);
+ goto err;
+ }
+
+ if (!force && sb.st_size >= isb.st_size) {
+ if (verbose)
+ (void)printf("%s: file would grow; left unmodified\n", in);
+ if (unlink(out))
+ cwarn("%s", out);
+ goto err;
+ }
+
+ setfile(out, &isb);
+
+ if (unlink(in))
+ cwarn("%s", in);
+
+ if (verbose) {
+ (void)printf("%s: ", out);
+ if (isb.st_size > sb.st_size)
+ (void)printf("%.0f%% compression\n",
+ ((float)sb.st_size / isb.st_size) * 100.0);
+ else
+ (void)printf("%.0f%% expansion\n",
+ ((float)isb.st_size / sb.st_size) * 100.0);
+ }
+ }
+ return;
+
+err: if (ofp) {
+ if (oreg)
+ (void)unlink(out);
+ (void)fclose(ofp);
+ }
+ if (ifp)
+ (void)fclose(ifp);
+}
+
+void
+decompress(in, out, bits)
+ char *in, *out;
+ int bits;
+{
+ register int nr;
+ struct stat sb;
+ FILE *ifp, *ofp;
+ int exists, isreg, oreg;
+ u_char buf[1024];
+
+ exists = !stat(out, &sb);
+ if (!force && exists && S_ISREG(sb.st_mode) && !permission(out))
+ return;
+ isreg = oreg = !exists || S_ISREG(sb.st_mode);
+
+ ifp = ofp = NULL;
+ if ((ofp = fopen(out, "w")) == NULL) {
+ cwarn("%s", out);
+ return;
+ }
+
+ if ((ifp = zopen(in, "r", bits)) == NULL) {
+ cwarn("%s", in);
+ goto err;
+ }
+ if (stat(in, &sb)) {
+ cwarn("%s", in);
+ goto err;
+ }
+ if (!S_ISREG(sb.st_mode))
+ isreg = 0;
+
+ while ((nr = fread(buf, 1, sizeof(buf), ifp)) != 0)
+ if (fwrite(buf, 1, nr, ofp) != nr) {
+ cwarn("%s", out);
+ goto err;
+ }
+
+ if (ferror(ifp) || fclose(ifp)) {
+ cwarn("%s", in);
+ goto err;
+ }
+ ifp = NULL;
+
+ if (fclose(ofp)) {
+ cwarn("%s", out);
+ goto err;
+ }
+
+ if (isreg) {
+ setfile(out, &sb);
+
+ if (unlink(in))
+ cwarn("%s", in);
+ }
+ return;
+
+err: if (ofp) {
+ if (oreg)
+ (void)unlink(out);
+ (void)fclose(ofp);
+ }
+ if (ifp)
+ (void)fclose(ifp);
+}
+
+void
+setfile(name, fs)
+ char *name;
+ register struct stat *fs;
+{
+ static struct timeval tv[2];
+
+ fs->st_mode &= S_ISUID|S_ISGID|S_IRWXU|S_IRWXG|S_IRWXO;
+
+ TIMESPEC_TO_TIMEVAL(&tv[0], &fs->st_atimespec);
+ TIMESPEC_TO_TIMEVAL(&tv[1], &fs->st_mtimespec);
+ if (utimes(name, tv))
+ cwarn("utimes: %s", name);
+
+ /*
+ * Changing the ownership probably won't succeed, unless we're root
+ * or POSIX_CHOWN_RESTRICTED is not set. Set uid/gid before setting
+ * the mode; current BSD behavior is to remove all setuid bits on
+ * chown. If chown fails, lose setuid/setgid bits.
+ */
+ if (chown(name, fs->st_uid, fs->st_gid)) {
+ if (errno != EPERM)
+ cwarn("chown: %s", name);
+ fs->st_mode &= ~(S_ISUID|S_ISGID);
+ }
+ if (chmod(name, fs->st_mode))
+ cwarn("chown: %s", name);
+
+ if (chflags(name, fs->st_flags))
+ cwarn("chflags: %s", name);
+}
+
+int
+permission(fname)
+ char *fname;
+{
+ int ch, first;
+
+ if (!isatty(fileno(stderr)))
+ return (0);
+ (void)fprintf(stderr, "overwrite %s? ", fname);
+ first = ch = getchar();
+ while (ch != '\n' && ch != EOF)
+ ch = getchar();
+ return (first == 'y');
+}
+
+void
+usage(iscompress)
+ int iscompress;
+{
+ if (iscompress)
+ (void)fprintf(stderr,
+ "usage: compress [-cfv] [-b bits] [file ...]\n");
+ else
+ (void)fprintf(stderr,
+ "usage: uncompress [-c] [-b bits] [file ...]\n");
+ exit(1);
+}
+
+void
+#if __STDC__
+cwarnx(const char *fmt, ...)
+#else
+cwarnx(fmt, va_alist)
+ int eval;
+ const char *fmt;
+ va_dcl
+#endif
+{
+ va_list ap;
+#if __STDC__
+ va_start(ap, fmt);
+#else
+ va_start(ap);
+#endif
+ vwarnx(fmt, ap);
+ va_end(ap);
+ eval = 1;
+}
+
+void
+#if __STDC__
+cwarn(const char *fmt, ...)
+#else
+cwarn(fmt, va_alist)
+ int eval;
+ const char *fmt;
+ va_dcl
+#endif
+{
+ va_list ap;
+#if __STDC__
+ va_start(ap, fmt);
+#else
+ va_start(ap);
+#endif
+ vwarn(fmt, ap);
+ va_end(ap);
+ eval = 1;
+}
diff --git a/usr.bin/compress/doc/NOTES b/usr.bin/compress/doc/NOTES
new file mode 100644
index 000000000000..7c28c9c22b4f
--- /dev/null
+++ b/usr.bin/compress/doc/NOTES
@@ -0,0 +1,139 @@
+From: James A. Woods <jaw@eos.arc.nasa.gov>
+
+>From vn Fri Dec 2 18:05:27 1988
+Subject: Re: Looking for C source for RSA
+Newsgroups: sci.crypt
+
+# Illegitimi noncarborundum
+
+Patents are a tar pit.
+
+A good case can be made that most are just a license to sue, and nothing
+is illegal until a patent is upheld in court.
+
+For example, if you receive netnews by means other than 'nntp',
+these very words are being modulated by 'compress',
+a variation on the patented Lempel-Ziv-Welch algorithm.
+
+Original Ziv-Lempel is patent number 4,464,650, and the more powerful
+LZW method is #4,558,302. Yet despite any similarities between 'compress'
+and LZW (the public-domain 'compress' code was designed and given to the
+world before the ink on the Welch patent was dry), no attorneys from Sperry
+(the assignee) have asked you to unplug your Usenet connection.
+
+Why? I can't speak for them, but it is possible the claims are too broad,
+or, just as bad, not broad enough. ('compress' does things not mentioned
+in the Welch patent.) Maybe they realize that they can commercialize
+LZW better by selling hardware implementations rather than by licensing
+software. Again, the LZW software delineated in the patent is *not*
+the same as that of 'compress'.
+
+At any rate, court-tested software patents are a different animal;
+corporate patents in a portfolio are usually traded like baseball cards
+to shut out small fry rather than actually be defended before
+non-technical juries. Perhaps RSA will undergo this test successfully,
+although the grant to "exclude others from making, using, or selling"
+the invention would then only apply to the U.S. (witness the
+Genentech patent of the TPA molecule in the U.S. but struck down
+in Great Britain as too broad.)
+
+The concept is still exotic for those who learned in school the rule of thumb
+that one may patent "apparatus" but not an "idea".
+Apparently this all changed in Diamond v. Diehr (1981) when the U. S. Supreme
+Court reversed itself.
+
+Scholars should consult the excellent article in the Washington and Lee
+Law Review (fall 1984, vol. 41, no. 4) by Anthony and Colwell for a
+comprehensive survey of an area which will remain murky for some time.
+
+Until the dust clears, how you approach ideas which are patented depends
+on how paranoid you are of a legal onslaught. Arbitrary? Yes. But
+the patent bar the the CCPA (Court of Customs and Patent Appeals)
+thanks you for any uncertainty as they, at least, stand to gain
+from any trouble.
+
+=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
+From: James A. Woods <jaw@eos.arc.nasa.gov>
+Subject: Re: Looking for C source for RSA (actually 'compress' patents)
+
+ In article <2042@eos.UUCP> you write:
+ >The concept is still exotic for those who learned in school the rule of thumb
+ >that one may patent "apparatus" but not an "idea".
+
+A rule of thumb that has never been completely valid, as any chemical
+engineer can tell you. (Chemical processes were among the earliest patents,
+as I recall.)
+
+ ah yes -- i date myself when relaying out-of-date advice from elderly
+ attorneys who don't even specialize in patents. one other interesting
+ class of patents include the output of optical lens design programs,
+ which yield formulae which can then fairly directly can be molded
+ into glass. although there are restrictions on patenting equations,
+ the "embedded systems" seem to fly past the legal gauntlets.
+
+ anyway, i'm still learning about intellectual property law after
+ several conversations from a unisys (nee sperry) lawyer re 'compress'.
+
+ it's more complicated than this, but they're letting (oral
+ communication only) software versions of 'compress' slide
+ as far as licensing fees go. this includes 'arc', 'stuffit',
+ and other commercial wrappers for 'compress'. yet they are
+ signing up licensees for hardware chips. hewlett-packard
+ supposedly has an active vlsi project, and unisys has
+ board-level lzw-based tape controllers. (to build lzw into
+ a disk controller would be strange, as you'd have to build
+ in a filesystem too!)
+
+ it's byzantine
+ that unisys is in a tiff with hp regarding the patents,
+ after discovering some sort of "compress" button on some
+ hp terminal product. why? well, professor abraham lempel jumped
+ from being department chairman of computer science at technion in
+ israel to sperry (where he got the first patent), but then to work
+ at hewlett-packard on sabbatical. the second welch patent
+ is only weakly derivative of the first, so they want chip
+ licenses and hp relented. however, everyone agrees something
+ like the current unix implementation is the way to go with
+ software, so hp (and ucb) long ago asked spencer thomas and i to sign
+ off on copyright permission (although they didn't need to, it being pd).
+ lempel, hp, and unisys grumbles they can't make money off the
+ software since a good free implementation (not the best --
+ i have more ideas!) escaped via usenet. (lempel's own pascal
+ code was apparently horribly slow.)
+ i don't follow the ibm 'arc' legal bickering; my impression
+ is that the pc folks are making money off the archiver/wrapper
+ look/feel of the thing [if ms-dos can be said to have a look and feel].
+
+ now where is telebit with the compress firmware? in a limbo
+ netherworld, probably, with sperry still welcoming outfits
+ to sign patent licenses, a common tactic to bring other small fry
+ into the fold. the guy who crammed 12-bit compess into the modem
+ there left. also what is transpiring with 'compress' and sys 5 rel 4?
+ beats me, but if sperry got a hold of them on these issues,
+ at&t would likely re-implement another algorithm if they
+ thought 'compress' infringes. needful to say, i don't think
+ it does after the abovementioned legal conversation.
+ my own beliefs on whether algorithms should be patentable at all
+ change with the weather. if the courts finally nail down
+ patent protection for algorithms, academic publication in
+ textbooks will be somewhat at odds with the engineering world,
+ where the textbook codes will simply be a big tease to get
+ money into the patent holder coffers...
+
+ oh, if you implement lzw from the patent, you won't get
+ good rates because it doesn't mention adaptive table reset,
+ lack thereof being *the* serious deficiency of thomas' first version.
+
+ now i know that patent law generally protects against independent
+ re-invention (like the 'xor' hash function pleasantly mentioned
+ in the patent [but not the paper]).
+ but the upshot is that if anyone ever wanted to sue us,
+ we're partially covered with
+ independently-developed twists, plus the fact that some of us work
+ in a bureacratic morass (as contractor to a public agency in my case).
+
+ quite a mess, huh? i've wanted to tell someone this stuff
+ for a long time, for posterity if nothing else.
+
+james
+
diff --git a/usr.bin/compress/doc/README b/usr.bin/compress/doc/README
new file mode 100644
index 000000000000..6803287c207a
--- /dev/null
+++ b/usr.bin/compress/doc/README
@@ -0,0 +1,283 @@
+
+ @(#)README 8.1 (Berkeley) 6/9/93
+
+Compress version 4.0 improvements over 3.0:
+ o compress() speedup (10-50%) by changing division hash to xor
+ o decompress() speedup (5-10%)
+ o Memory requirements reduced (3-30%)
+ o Stack requirements reduced to less than 4kb
+ o Removed 'Big+Fast' compress code (FBITS) because of compress speedup
+ o Portability mods for Z8000 and PC/XT (but not zeus 3.2)
+ o Default to 'quiet' mode
+ o Unification of 'force' flags
+ o Manual page overhaul
+ o Portability enhancement for M_XENIX
+ o Removed text on #else and #endif
+ o Added "-V" switch to print version and options
+ o Added #defines for SIGNED_COMPARE_SLOW
+ o Added Makefile and "usermem" program
+ o Removed all floating point computations
+ o New programs: [deleted]
+
+The "usermem" script attempts to determine the maximum process size. Some
+editing of the script may be necessary (see the comments). [It should work
+fine on 4.3 bsd.] If you can't get it to work at all, just create file
+"USERMEM" containing the maximum process size in decimal.
+
+The following preprocessor symbols control the compilation of "compress.c":
+
+ o USERMEM Maximum process memory on the system
+ o SACREDMEM Amount to reserve for other proceses
+ o SIGNED_COMPARE_SLOW Unsigned compare instructions are faster
+ o NO_UCHAR Don't use "unsigned char" types
+ o BITS Overrules default set by USERMEM-SACREDMEM
+ o vax Generate inline assembler
+ o interdata Defines SIGNED_COMPARE_SLOW
+ o M_XENIX Makes arrays < 65536 bytes each
+ o pdp11 BITS=12, NO_UCHAR
+ o z8000 BITS=12
+ o pcxt BITS=12
+ o BSD4_2 Allow long filenames ( > 14 characters) &
+ Call setlinebuf(stderr)
+
+The difference "usermem-sacredmem" determines the maximum BITS that can be
+specified with the "-b" flag.
+
+memory: at least BITS
+------ -- ----- ----
+ 433,484 16
+ 229,600 15
+ 127,536 14
+ 73,464 13
+ 0 12
+
+The default is BITS=16.
+
+The maximum bits can be overrulled by specifying "-DBITS=bits" at
+compilation time.
+
+WARNING: files compressed on a large machine with more bits than allowed by
+a version of compress on a smaller machine cannot be decompressed! Use the
+"-b12" flag to generate a file on a large machine that can be uncompressed
+on a 16-bit machine.
+
+The output of compress 4.0 is fully compatible with that of compress 3.0.
+In other words, the output of compress 4.0 may be fed into uncompress 3.0 or
+the output of compress 3.0 may be fed into uncompress 4.0.
+
+The output of compress 4.0 not compatible with that of
+compress 2.0. However, compress 4.0 still accepts the output of
+compress 2.0. To generate output that is compatible with compress
+2.0, use the undocumented "-C" flag.
+
+ -from mod.sources, submitted by vax135!petsd!joe (Joe Orost), 8/1/85
+--------------------------------
+
+Enclosed is compress version 3.0 with the following changes:
+
+1. "Block" compression is performed. After the BITS run out, the
+ compression ratio is checked every so often. If it is decreasing,
+ the table is cleared and a new set of substrings are generated.
+
+ This makes the output of compress 3.0 not compatible with that of
+ compress 2.0. However, compress 3.0 still accepts the output of
+ compress 2.0. To generate output that is compatible with compress
+ 2.0, use the undocumented "-C" flag.
+
+2. A quiet "-q" flag has been added for use by the news system.
+
+3. The character chaining has been deleted and the program now uses
+ hashing. This improves the speed of the program, especially
+ during decompression. Other speed improvements have been made,
+ such as using putc() instead of fwrite().
+
+4. A large table is used on large machines when a relatively small
+ number of bits is specified. This saves much time when compressing
+ for a 16-bit machine on a 32-bit virtual machine. Note that the
+ speed improvement only occurs when the input file is > 30000
+ characters, and the -b BITS is less than or equal to the cutoff
+ described below.
+
+Most of these changes were made by James A. Woods (ames!jaw). Thank you
+James!
+
+To compile compress:
+
+ cc -O -DUSERMEM=usermem -o compress compress.c
+
+Where "usermem" is the amount of physical user memory available (in bytes).
+If any physical memory is to be reserved for other processes, put in
+"-DSACREDMEM sacredmem", where "sacredmem" is the amount to be reserved.
+
+The difference "usermem-sacredmem" determines the maximum BITS that can be
+specified, and the cutoff bits where the large+fast table is used.
+
+memory: at least BITS cutoff
+------ -- ----- ---- ------
+ 4,718,592 16 13
+ 2,621,440 16 12
+ 1,572,864 16 11
+ 1,048,576 16 10
+ 631,808 16 --
+ 329,728 15 --
+ 178,176 14 --
+ 99,328 13 --
+ 0 12 --
+
+The default memory size is 750,000 which gives a maximum BITS=16 and no
+large+fast table.
+
+The maximum bits can be overruled by specifying "-DBITS=bits" at
+compilation time.
+
+If your machine doesn't support unsigned characters, define "NO_UCHAR"
+when compiling.
+
+If your machine has "int" as 16-bits, define "SHORT_INT" when compiling.
+
+After compilation, move "compress" to a standard executable location, such
+as /usr/local. Then:
+ cd /usr/local
+ ln compress uncompress
+ ln compress zcat
+
+On machines that have a fixed stack size (such as Perkin-Elmer), set the
+stack to at least 12kb. ("setstack compress 12" on Perkin-Elmer).
+
+Next, install the manual (compress.l).
+ cp compress.l /usr/man/manl
+ cd /usr/man/manl
+ ln compress.l uncompress.l
+ ln compress.l zcat.l
+
+ - or -
+
+ cp compress.l /usr/man/man1/compress.1
+ cd /usr/man/man1
+ ln compress.1 uncompress.1
+ ln compress.1 zcat.1
+
+ regards,
+ petsd!joe
+
+Here is a note from the net:
+
+>From hplabs!pesnta!amd!turtlevax!ken Sat Jan 5 03:35:20 1985
+Path: ames!hplabs!pesnta!amd!turtlevax!ken
+From: ken@turtlevax.UUCP (Ken Turkowski)
+Newsgroups: net.sources
+Subject: Re: Compress release 3.0 : sample Makefile
+Organization: CADLINC, Inc. @ Menlo Park, CA
+
+In the compress 3.0 source recently posted to mod.sources, there is a
+#define variable which can be set for optimum performance on a machine
+with a large amount of memory. A program (usermem) to calculate the
+useable amount of physical user memory is enclosed, as well as a sample
+4.2bsd Vax Makefile for compress.
+
+Here is the README file from the previous version of compress (2.0):
+
+>Enclosed is compress.c version 2.0 with the following bugs fixed:
+>
+>1. The packed files produced by compress are different on different
+> machines and dependent on the vax sysgen option.
+> The bug was in the different byte/bit ordering on the
+> various machines. This has been fixed.
+>
+> This version is NOT compatible with the original vax posting
+> unless the '-DCOMPATIBLE' option is specified to the C
+> compiler. The original posting has a bug which I fixed,
+> causing incompatible files. I recommend you NOT to use this
+> option unless you already have a lot of packed files from
+> the original posting by thomas.
+>2. The exit status is not well defined (on some machines) causing the
+> scripts to fail.
+> The exit status is now 0,1 or 2 and is documented in
+> compress.l.
+>3. The function getopt() is not available in all C libraries.
+> The function getopt() is no longer referenced by the
+> program.
+>4. Error status is not being checked on the fwrite() and fflush() calls.
+> Fixed.
+>
+>The following enhancements have been made:
+>
+>1. Added facilities of "compact" into the compress program. "Pack",
+> "Unpack", and "Pcat" are no longer required (no longer supplied).
+>2. Installed work around for C compiler bug with "-O".
+>3. Added a magic number header (\037\235). Put the bits specified
+> in the file.
+>4. Added "-f" flag to force overwrite of output file.
+>5. Added "-c" flag and "zcat" program. 'ln compress zcat' after you
+> compile.
+>6. The 'uncompress' script has been deleted; simply
+> 'ln compress uncompress' after you compile and it will work.
+>7. Removed extra bit masking for machines that support unsigned
+> characters. If your machine doesn't support unsigned characters,
+> define "NO_UCHAR" when compiling.
+>
+>Compile "compress.c" with "-O -o compress" flags. Move "compress" to a
+>standard executable location, such as /usr/local. Then:
+> cd /usr/local
+> ln compress uncompress
+> ln compress zcat
+>
+>On machines that have a fixed stack size (such as Perkin-Elmer), set the
+>stack to at least 12kb. ("setstack compress 12" on Perkin-Elmer).
+>
+>Next, install the manual (compress.l).
+> cp compress.l /usr/man/manl - or -
+> cp compress.l /usr/man/man1/compress.1
+>
+>Here is the README that I sent with my first posting:
+>
+>>Enclosed is a modified version of compress.c, along with scripts to make it
+>>run identically to pack(1), unpack(1), an pcat(1). Here is what I
+>>(petsd!joe) and a colleague (petsd!peora!srd) did:
+>>
+>>1. Removed VAX dependencies.
+>>2. Changed the struct to separate arrays; saves mucho memory.
+>>3. Did comparisons in unsigned, where possible. (Faster on Perkin-Elmer.)
+>>4. Sorted the character next chain and changed the search to stop
+>>prematurely. This saves a lot on the execution time when compressing.
+>>
+>>This version is totally compatible with the original version. Even though
+>>lint(1) -p has no complaints about compress.c, it won't run on a 16-bit
+>>machine, due to the size of the arrays.
+>>
+>>Here is the README file from the original author:
+>>
+>>>Well, with all this discussion about file compression (for news batching
+>>>in particular) going around, I decided to implement the text compression
+>>>algorithm described in the June Computer magazine. The author claimed
+>>>blinding speed and good compression ratios. It's certainly faster than
+>>>compact (but, then, what wouldn't be), but it's also the same speed as
+>>>pack, and gets better compression than both of them. On 350K bytes of
+>>>unix-wizards, compact took about 8 minutes of CPU, pack took about 80
+>>>seconds, and compress (herein) also took 80 seconds. But, compact and
+>>>pack got about 30% compression, whereas compress got over 50%. So, I
+>>>decided I had something, and that others might be interested, too.
+>>>
+>>>As is probably true of compact and pack (although I haven't checked),
+>>>the byte order within a word is probably relevant here, but as long as
+>>>you stay on a single machine type, you should be ok. (Can anybody
+>>>elucidate on this?) There are a couple of asm's in the code (extv and
+>>>insv instructions), so anyone porting it to another machine will have to
+>>>deal with this anyway (and could probably make it compatible with Vax
+>>>byte order at the same time). Anyway, I've linted the code (both with
+>>>and without -p), so it should run elsewhere. Note the longs in the
+>>>code, you can take these out if you reduce BITS to <= 15.
+>>>
+>>>Have fun, and as always, if you make good enhancements, or bug fixes,
+>>>I'd like to see them.
+>>>
+>>>=Spencer (thomas@utah-20, {harpo,hplabs,arizona}!utah-cs!thomas)
+>>
+>> regards,
+>> joe
+>>
+>>--
+>>Full-Name: Joseph M. Orost
+>>UUCP: ..!{decvax,ucbvax,ihnp4}!vax135!petsd!joe
+>>US Mail: MS 313; Perkin-Elmer; 106 Apple St; Tinton Falls, NJ 07724
+>>Phone: (201) 870-5844
diff --git a/usr.bin/compress/doc/revision.log b/usr.bin/compress/doc/revision.log
new file mode 100644
index 000000000000..b1d8b24cc4f0
--- /dev/null
+++ b/usr.bin/compress/doc/revision.log
@@ -0,0 +1,116 @@
+/*
+ * $Header: compress.c,v 4.0 85/07/30 12:50:00 joe Release $
+ * $Log: compress.c,v $
+ * Revision 4.0 85/07/30 12:50:00 joe
+ * Removed ferror() calls in output routine on every output except first.
+ * Prepared for release to the world.
+ *
+ * Revision 3.6 85/07/04 01:22:21 joe
+ * Remove much wasted storage by overlaying hash table with the tables
+ * used by decompress: tab_suffix[1<<BITS], stack[8000]. Updated USERMEM
+ * computations. Fixed dump_tab() DEBUG routine.
+ *
+ * Revision 3.5 85/06/30 20:47:21 jaw
+ * Change hash function to use exclusive-or. Rip out hash cache. These
+ * speedups render the megamemory version defunct, for now. Make decoder
+ * stack global. Parts of the RCS trunks 2.7, 2.6, and 2.1 no longer apply.
+ *
+ * Revision 3.4 85/06/27 12:00:00 ken
+ * Get rid of all floating-point calculations by doing all compression ratio
+ * calculations in fixed point.
+ *
+ * Revision 3.3 85/06/24 21:53:24 joe
+ * Incorporate portability suggestion for M_XENIX. Got rid of text on #else
+ * and #endif lines. Cleaned up #ifdefs for vax and interdata.
+ *
+ * Revision 3.2 85/06/06 21:53:24 jaw
+ * Incorporate portability suggestions for Z8000, IBM PC/XT from mailing list.
+ * Default to "quiet" output (no compression statistics).
+ *
+ * Revision 3.1 85/05/12 18:56:13 jaw
+ * Integrate decompress() stack speedups (from early pointer mods by McKie).
+ * Repair multi-file USERMEM gaffe. Unify 'force' flags to mimic semantics
+ * of SVR2 'pack'. Streamline block-compress table clear logic. Increase
+ * output byte count by magic number size.
+ *
+ * Revision 3.0 84/11/27 11:50:00 petsd!joe
+ * Set HSIZE depending on BITS. Set BITS depending on USERMEM. Unrolled
+ * loops in clear routines. Added "-C" flag for 2.0 compatibility. Used
+ * unsigned compares on Perkin-Elmer. Fixed foreground check.
+ *
+ * Revision 2.7 84/11/16 19:35:39 ames!jaw
+ * Cache common hash codes based on input statistics; this improves
+ * performance for low-density raster images. Pass on #ifdef bundle
+ * from Turkowski.
+ *
+ * Revision 2.6 84/11/05 19:18:21 ames!jaw
+ * Vary size of hash tables to reduce time for small files.
+ * Tune PDP-11 hash function.
+ *
+ * Revision 2.5 84/10/30 20:15:14 ames!jaw
+ * Junk chaining; replace with the simpler (and, on the VAX, faster)
+ * double hashing, discussed within. Make block compression standard.
+ *
+ * Revision 2.4 84/10/16 11:11:11 ames!jaw
+ * Introduce adaptive reset for block compression, to boost the rate
+ * another several percent. (See mailing list notes.)
+ *
+ * Revision 2.3 84/09/22 22:00:00 petsd!joe
+ * Implemented "-B" block compress. Implemented REVERSE sorting of tab_next.
+ * Bug fix for last bits. Changed fwrite to putchar loop everywhere.
+ *
+ * Revision 2.2 84/09/18 14:12:21 ames!jaw
+ * Fold in news changes, small machine typedef from thomas,
+ * #ifdef interdata from joe.
+ *
+ * Revision 2.1 84/09/10 12:34:56 ames!jaw
+ * Configured fast table lookup for 32-bit machines.
+ * This cuts user time in half for b <= FBITS, and is useful for news batching
+ * from VAX to PDP sites. Also sped up decompress() [fwrite->putc] and
+ * added signal catcher [plus beef in writeerr()] to delete effluvia.
+ *
+ * Revision 2.0 84/08/28 22:00:00 petsd!joe
+ * Add check for foreground before prompting user. Insert maxbits into
+ * compressed file. Force file being uncompressed to end with ".Z".
+ * Added "-c" flag and "zcat". Prepared for release.
+ *
+ * Revision 1.10 84/08/24 18:28:00 turtlevax!ken
+ * Will only compress regular files (no directories), added a magic number
+ * header (plus an undocumented -n flag to handle old files without headers),
+ * added -f flag to force overwriting of possibly existing destination file,
+ * otherwise the user is prompted for a response. Will tack on a .Z to a
+ * filename if it doesn't have one when decompressing. Will only replace
+ * file if it was compressed.
+ *
+ * Revision 1.9 84/08/16 17:28:00 turtlevax!ken
+ * Removed scanargs(), getopt(), added .Z extension and unlimited number of
+ * filenames to compress. Flags may be clustered (-Ddvb12) or separated
+ * (-D -d -v -b 12), or combination thereof. Modes and other status is
+ * copied with copystat(). -O bug for 4.2 seems to have disappeared with
+ * 1.8.
+ *
+ * Revision 1.8 84/08/09 23:15:00 joe
+ * Made it compatible with vax version, installed jim's fixes/enhancements
+ *
+ * Revision 1.6 84/08/01 22:08:00 joe
+ * Sped up algorithm significantly by sorting the compress chain.
+ *
+ * Revision 1.5 84/07/13 13:11:00 srd
+ * Added C version of vax asm routines. Changed structure to arrays to
+ * save much memory. Do unsigned compares where possible (faster on
+ * Perkin-Elmer)
+ *
+ * Revision 1.4 84/07/05 03:11:11 thomas
+ * Clean up the code a little and lint it. (Lint complains about all
+ * the regs used in the asm, but I'm not going to "fix" this.)
+ *
+ * Revision 1.3 84/07/05 02:06:54 thomas
+ * Minor fixes.
+ *
+ * Revision 1.2 84/07/05 00:27:27 thomas
+ * Add variable bit length output.
+ *
+ */
+
+static char rcs_ident[] =
+ "$Header: compress.c,v 4.0 85/07/30 12:50:00 joe Release $";
diff --git a/usr.bin/compress/zcat.sh b/usr.bin/compress/zcat.sh
new file mode 100644
index 000000000000..c4931e486bb0
--- /dev/null
+++ b/usr.bin/compress/zcat.sh
@@ -0,0 +1,37 @@
+#!/bin/sh -
+#
+# Copyright (c) 1992, 1993
+# The Regents of the University of California. All rights reserved.
+#
+# Redistribution and use in source and binary forms, with or without
+# modification, are permitted provided that the following conditions
+# are met:
+# 1. Redistributions of source code must retain the above copyright
+# notice, this list of conditions and the following disclaimer.
+# 2. Redistributions in binary form must reproduce the above copyright
+# notice, this list of conditions and the following disclaimer in the
+# documentation and/or other materials provided with the distribution.
+# 3. All advertising materials mentioning features or use of this software
+# must display the following acknowledgement:
+# This product includes software developed by the University of
+# California, Berkeley and its contributors.
+# 4. Neither the name of the University nor the names of its contributors
+# may be used to endorse or promote products derived from this software
+# without specific prior written permission.
+#
+# THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+# ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+# IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+# ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+# FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+# DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+# OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+# HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+# LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+# OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+# SUCH DAMAGE.
+#
+# @(#)zcat.sh 8.1 (Berkeley) 6/6/93
+#
+
+uncompress -c $*
diff --git a/usr.bin/compress/zopen.3 b/usr.bin/compress/zopen.3
new file mode 100644
index 000000000000..853462f5057a
--- /dev/null
+++ b/usr.bin/compress/zopen.3
@@ -0,0 +1,139 @@
+.\" Copyright (c) 1992, 1993
+.\" The Regents of the University of California. All rights reserved.
+.\"
+.\" Redistribution and use in source and binary forms, with or without
+.\" modification, are permitted provided that the following conditions
+.\" are met:
+.\" 1. Redistributions of source code must retain the above copyright
+.\" notice, this list of conditions and the following disclaimer.
+.\" 2. Redistributions in binary form must reproduce the above copyright
+.\" notice, this list of conditions and the following disclaimer in the
+.\" documentation and/or other materials provided with the distribution.
+.\" 3. All advertising materials mentioning features or use of this software
+.\" must display the following acknowledgement:
+.\" This product includes software developed by the University of
+.\" California, Berkeley and its contributors.
+.\" 4. Neither the name of the University nor the names of its contributors
+.\" may be used to endorse or promote products derived from this software
+.\" without specific prior written permission.
+.\"
+.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+.\" SUCH DAMAGE.
+.\"
+.\" @(#)zopen.3 8.1 (Berkeley) 6/9/93
+.\"
+.Dd June 9, 1993
+.Dt ZOPEN 3
+.Os
+.Sh NAME
+.Nm zopen
+.Nd compressed stream open function
+.Sh SYNOPSIS
+.Fd #include <stdio.h>
+.Ft FILE *
+.Fn zopen "const char *path" "const char *mode" "int bits"
+.Sh DESCRIPTION
+The
+.Fn zopen
+function
+opens the compressed file whose name is the string pointed to by
+.Fa path
+and associates a stream with it.
+.Pp
+The argument
+.Fa mode
+points to one of the following one-character strings:
+.Bl -tag -width indent
+.It Dq Li r
+Open compressed file for reading.
+The stream is positioned at the beginning of the file.
+.It Dq Li w
+Truncate file to zero length or create compressed file for writing.
+The stream is positioned at the beginning of the file.
+.El
+.Pp
+Any created files will have mode
+.Pf \\*q Dv S_IRUSR
+\&|
+.Dv S_IWUSR
+\&|
+.Dv S_IRGRP
+\&|
+.Dv S_IWGRP
+\&|
+.Dv S_IROTH
+\&|
+.Dv S_IWOTH Ns \\*q
+.Pq Li 0666 ,
+as modified by the process'
+umask value (see
+.Xr umask 2 ) .
+.Pp
+Files may only be read or written.
+Seek operations are not allowed.
+.Pp
+The
+.Fa bits
+argument, if non-zero, is set to the bits code limit.
+If zero, the default is 16.
+See
+.Fn compress 1
+for more information.
+.Sh RETURN VALUES
+Upon successful completion
+.Fn zopen
+returns a
+.Tn FILE
+pointer.
+Otherwise,
+.Dv NULL
+is returned and the global variable
+.Va errno
+is set to indicate the error.
+.Sh ERRORS
+.Bl -tag -width [EINVAL]
+.It Bq Er EINVAL
+The
+.Fa mode
+or
+.Fa bits
+arguments specified to
+.Fn zopen
+were invalid.
+.It Bq Er EFTYPE
+The compressed file starts with an invalid header, or the compressed
+file is compressed with more bits than can be handled.
+.El
+.Pp
+The
+.Fn zopen
+function may also fail and set
+.Va errno
+for any of the errors specified for the routines
+.Xr fopen 3
+or
+.Xr funopen 3 .
+.Sh SEE ALSO
+.Xr compress 1 ,
+.Xr fopen 3 ,
+.Xr funopen 3
+.Sh HISTORY
+The
+.Nm zopen
+function
+first appeared in 4.4BSD.
+.Sh BUGS
+The
+.Fn zopen
+function
+may not be portable to systems other than
+.Bx .
diff --git a/usr.bin/compress/zopen.c b/usr.bin/compress/zopen.c
new file mode 100644
index 000000000000..b76fca6edada
--- /dev/null
+++ b/usr.bin/compress/zopen.c
@@ -0,0 +1,740 @@
+/*-
+ * Copyright (c) 1985, 1986, 1992, 1993
+ * The Regents of the University of California. All rights reserved.
+ *
+ * This code is derived from software contributed to Berkeley by
+ * Diomidis Spinellis and James A. Woods, derived from original
+ * work by Spencer Thomas and Joseph Orost.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in the
+ * documentation and/or other materials provided with the distribution.
+ * 3. All advertising materials mentioning features or use of this software
+ * must display the following acknowledgement:
+ * This product includes software developed by the University of
+ * California, Berkeley and its contributors.
+ * 4. Neither the name of the University nor the names of its contributors
+ * may be used to endorse or promote products derived from this software
+ * without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+#if defined(LIBC_SCCS) && !defined(lint)
+static char sccsid[] = "@(#)zopen.c 8.1 (Berkeley) 6/27/93";
+#endif /* LIBC_SCCS and not lint */
+
+/*-
+ * fcompress.c - File compression ala IEEE Computer, June 1984.
+ *
+ * Compress authors:
+ * Spencer W. Thomas (decvax!utah-cs!thomas)
+ * Jim McKie (decvax!mcvax!jim)
+ * Steve Davies (decvax!vax135!petsd!peora!srd)
+ * Ken Turkowski (decvax!decwrl!turtlevax!ken)
+ * James A. Woods (decvax!ihnp4!ames!jaw)
+ * Joe Orost (decvax!vax135!petsd!joe)
+ *
+ * Cleaned up and converted to library returning I/O streams by
+ * Diomidis Spinellis <dds@doc.ic.ac.uk>.
+ *
+ * zopen(filename, mode, bits)
+ * Returns a FILE * that can be used for read or write. The modes
+ * supported are only "r" and "w". Seeking is not allowed. On
+ * reading the file is decompressed, on writing it is compressed.
+ * The output is compatible with compress(1) with 16 bit tables.
+ * Any file produced by compress(1) can be read.
+ */
+
+#include <sys/param.h>
+#include <sys/stat.h>
+
+#include <ctype.h>
+#include <errno.h>
+#include <signal.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+
+#define BITS 16 /* Default bits. */
+#define HSIZE 69001 /* 95% occupancy */
+
+/* A code_int must be able to hold 2**BITS values of type int, and also -1. */
+typedef long code_int;
+typedef long count_int;
+
+typedef u_char char_type;
+static char_type magic_header[] =
+ {'\037', '\235'}; /* 1F 9D */
+
+#define BIT_MASK 0x1f /* Defines for third byte of header. */
+#define BLOCK_MASK 0x80
+
+/*
+ * Masks 0x40 and 0x20 are free. I think 0x20 should mean that there is
+ * a fourth header byte (for expansion).
+ */
+#define INIT_BITS 9 /* Initial number of bits/code. */
+
+#define MAXCODE(n_bits) ((1 << (n_bits)) - 1)
+
+struct s_zstate {
+ FILE *zs_fp; /* File stream for I/O */
+ char zs_mode; /* r or w */
+ enum {
+ S_START, S_MIDDLE, S_EOF
+ } zs_state; /* State of computation */
+ int zs_n_bits; /* Number of bits/code. */
+ int zs_maxbits; /* User settable max # bits/code. */
+ code_int zs_maxcode; /* Maximum code, given n_bits. */
+ code_int zs_maxmaxcode; /* Should NEVER generate this code. */
+ count_int zs_htab [HSIZE];
+ u_short zs_codetab [HSIZE];
+ code_int zs_hsize; /* For dynamic table sizing. */
+ code_int zs_free_ent; /* First unused entry. */
+ /*
+ * Block compression parameters -- after all codes are used up,
+ * and compression rate changes, start over.
+ */
+ int zs_block_compress;
+ int zs_clear_flg;
+ long zs_ratio;
+ count_int zs_checkpoint;
+ int zs_offset;
+ long zs_in_count; /* Length of input. */
+ long zs_bytes_out; /* Length of compressed output. */
+ long zs_out_count; /* # of codes output (for debugging). */
+ char_type zs_buf[BITS];
+ union {
+ struct {
+ long zs_fcode;
+ code_int zs_ent;
+ code_int zs_hsize_reg;
+ int zs_hshift;
+ } w; /* Write paramenters */
+ struct {
+ char_type *zs_stackp;
+ int zs_finchar;
+ code_int zs_code, zs_oldcode, zs_incode;
+ int zs_roffset, zs_size;
+ char_type zs_gbuf[BITS];
+ } r; /* Read parameters */
+ } u;
+};
+
+/* Definitions to retain old variable names */
+#define fp zs->zs_fp
+#define zmode zs->zs_mode
+#define state zs->zs_state
+#define n_bits zs->zs_n_bits
+#define maxbits zs->zs_maxbits
+#define maxcode zs->zs_maxcode
+#define maxmaxcode zs->zs_maxmaxcode
+#define htab zs->zs_htab
+#define codetab zs->zs_codetab
+#define hsize zs->zs_hsize
+#define free_ent zs->zs_free_ent
+#define block_compress zs->zs_block_compress
+#define clear_flg zs->zs_clear_flg
+#define ratio zs->zs_ratio
+#define checkpoint zs->zs_checkpoint
+#define offset zs->zs_offset
+#define in_count zs->zs_in_count
+#define bytes_out zs->zs_bytes_out
+#define out_count zs->zs_out_count
+#define buf zs->zs_buf
+#define fcode zs->u.w.zs_fcode
+#define hsize_reg zs->u.w.zs_hsize_reg
+#define ent zs->u.w.zs_ent
+#define hshift zs->u.w.zs_hshift
+#define stackp zs->u.r.zs_stackp
+#define finchar zs->u.r.zs_finchar
+#define code zs->u.r.zs_code
+#define oldcode zs->u.r.zs_oldcode
+#define incode zs->u.r.zs_incode
+#define roffset zs->u.r.zs_roffset
+#define size zs->u.r.zs_size
+#define gbuf zs->u.r.zs_gbuf
+
+/*
+ * To save much memory, we overlay the table used by compress() with those
+ * used by decompress(). The tab_prefix table is the same size and type as
+ * the codetab. The tab_suffix table needs 2**BITS characters. We get this
+ * from the beginning of htab. The output stack uses the rest of htab, and
+ * contains characters. There is plenty of room for any possible stack
+ * (stack used to be 8000 characters).
+ */
+
+#define htabof(i) htab[i]
+#define codetabof(i) codetab[i]
+
+#define tab_prefixof(i) codetabof(i)
+#define tab_suffixof(i) ((char_type *)(htab))[i]
+#define de_stack ((char_type *)&tab_suffixof(1 << BITS))
+
+#define CHECK_GAP 10000 /* Ratio check interval. */
+
+/*
+ * the next two codes should not be changed lightly, as they must not
+ * lie within the contiguous general code space.
+ */
+#define FIRST 257 /* First free entry. */
+#define CLEAR 256 /* Table clear output code. */
+
+static int cl_block __P((struct s_zstate *));
+static void cl_hash __P((struct s_zstate *, count_int));
+static code_int getcode __P((struct s_zstate *));
+static int output __P((struct s_zstate *, code_int));
+static int zclose __P((void *));
+static int zread __P((void *, char *, int));
+static int zwrite __P((void *, const char *, int));
+
+/*-
+ * Algorithm from "A Technique for High Performance Data Compression",
+ * Terry A. Welch, IEEE Computer Vol 17, No 6 (June 1984), pp 8-19.
+ *
+ * Algorithm:
+ * Modified Lempel-Ziv method (LZW). Basically finds common
+ * substrings and replaces them with a variable size code. This is
+ * deterministic, and can be done on the fly. Thus, the decompression
+ * procedure needs no input table, but tracks the way the table was built.
+ */
+
+/*-
+ * compress write
+ *
+ * Algorithm: use open addressing double hashing (no chaining) on the
+ * prefix code / next character combination. We do a variant of Knuth's
+ * algorithm D (vol. 3, sec. 6.4) along with G. Knott's relatively-prime
+ * secondary probe. Here, the modular division first probe is gives way
+ * to a faster exclusive-or manipulation. Also do block compression with
+ * an adaptive reset, whereby the code table is cleared when the compression
+ * ratio decreases, but after the table fills. The variable-length output
+ * codes are re-sized at this point, and a special CLEAR code is generated
+ * for the decompressor. Late addition: construct the table according to
+ * file size for noticeable speed improvement on small files. Please direct
+ * questions about this implementation to ames!jaw.
+ */
+static int
+zwrite(cookie, wbp, num)
+ void *cookie;
+ const char *wbp;
+ int num;
+{
+ register code_int i;
+ register int c, disp;
+ struct s_zstate *zs;
+ const u_char *bp;
+ u_char tmp;
+ int count;
+
+ if (num == 0)
+ return (0);
+
+ zs = cookie;
+ count = num;
+ bp = (u_char *)wbp;
+ if (state == S_MIDDLE)
+ goto middle;
+ state = S_MIDDLE;
+
+ maxmaxcode = 1L << BITS;
+ if (fwrite(magic_header,
+ sizeof(char), sizeof(magic_header), fp) != sizeof(magic_header))
+ return (-1);
+ tmp = (u_char)(BITS | block_compress);
+ if (fwrite(&tmp, sizeof(char), sizeof(tmp), fp) != sizeof(tmp))
+ return (-1);
+
+ offset = 0;
+ bytes_out = 3; /* Includes 3-byte header mojo. */
+ out_count = 0;
+ clear_flg = 0;
+ ratio = 0;
+ in_count = 1;
+ checkpoint = CHECK_GAP;
+ maxcode = MAXCODE(n_bits = INIT_BITS);
+ free_ent = ((block_compress) ? FIRST : 256);
+
+ ent = *bp++;
+ --count;
+
+ hshift = 0;
+ for (fcode = (long)hsize; fcode < 65536L; fcode *= 2L)
+ hshift++;
+ hshift = 8 - hshift; /* Set hash code range bound. */
+
+ hsize_reg = hsize;
+ cl_hash(zs, (count_int)hsize_reg); /* Clear hash table. */
+
+middle: for (i = 0; count--;) {
+ c = *bp++;
+ in_count++;
+ fcode = (long)(((long)c << maxbits) + ent);
+ i = ((c << hshift) ^ ent); /* Xor hashing. */
+
+ if (htabof(i) == fcode) {
+ ent = codetabof(i);
+ continue;
+ } else if ((long)htabof(i) < 0) /* Empty slot. */
+ goto nomatch;
+ disp = hsize_reg - i; /* Secondary hash (after G. Knott). */
+ if (i == 0)
+ disp = 1;
+probe: if ((i -= disp) < 0)
+ i += hsize_reg;
+
+ if (htabof(i) == fcode) {
+ ent = codetabof(i);
+ continue;
+ }
+ if ((long)htabof(i) >= 0)
+ goto probe;
+nomatch: if (output(zs, (code_int) ent) == -1)
+ return (-1);
+ out_count++;
+ ent = c;
+ if (free_ent < maxmaxcode) {
+ codetabof(i) = free_ent++; /* code -> hashtable */
+ htabof(i) = fcode;
+ } else if ((count_int)in_count >=
+ checkpoint && block_compress) {
+ if (cl_block(zs) == -1)
+ return (-1);
+ }
+ }
+ return (num);
+}
+
+static int
+zclose(cookie)
+ void *cookie;
+{
+ struct s_zstate *zs;
+ int rval;
+
+ zs = cookie;
+ if (zmode == 'w') { /* Put out the final code. */
+ if (output(zs, (code_int) ent) == -1) {
+ (void)fclose(fp);
+ free(zs);
+ return (-1);
+ }
+ out_count++;
+ if (output(zs, (code_int) - 1) == -1) {
+ (void)fclose(fp);
+ free(zs);
+ return (-1);
+ }
+ }
+ rval = fclose(fp) == EOF ? -1 : 0;
+ free(zs);
+ return (rval);
+}
+
+/*-
+ * Output the given code.
+ * Inputs:
+ * code: A n_bits-bit integer. If == -1, then EOF. This assumes
+ * that n_bits =< (long)wordsize - 1.
+ * Outputs:
+ * Outputs code to the file.
+ * Assumptions:
+ * Chars are 8 bits long.
+ * Algorithm:
+ * Maintain a BITS character long buffer (so that 8 codes will
+ * fit in it exactly). Use the VAX insv instruction to insert each
+ * code in turn. When the buffer fills up empty it and start over.
+ */
+
+static char_type lmask[9] =
+ {0xff, 0xfe, 0xfc, 0xf8, 0xf0, 0xe0, 0xc0, 0x80, 0x00};
+static char_type rmask[9] =
+ {0x00, 0x01, 0x03, 0x07, 0x0f, 0x1f, 0x3f, 0x7f, 0xff};
+
+static int
+output(zs, ocode)
+ struct s_zstate *zs;
+ code_int ocode;
+{
+ register int bits, r_off;
+ register char_type *bp;
+
+ r_off = offset;
+ bits = n_bits;
+ bp = buf;
+ if (ocode >= 0) {
+ /* Get to the first byte. */
+ bp += (r_off >> 3);
+ r_off &= 7;
+ /*
+ * Since ocode is always >= 8 bits, only need to mask the first
+ * hunk on the left.
+ */
+ *bp = (*bp & rmask[r_off]) | (ocode << r_off) & lmask[r_off];
+ bp++;
+ bits -= (8 - r_off);
+ ocode >>= 8 - r_off;
+ /* Get any 8 bit parts in the middle (<=1 for up to 16 bits). */
+ if (bits >= 8) {
+ *bp++ = ocode;
+ ocode >>= 8;
+ bits -= 8;
+ }
+ /* Last bits. */
+ if (bits)
+ *bp = ocode;
+ offset += n_bits;
+ if (offset == (n_bits << 3)) {
+ bp = buf;
+ bits = n_bits;
+ bytes_out += bits;
+ if (fwrite(bp, sizeof(char), bits, fp) != bits)
+ return (-1);
+ bp += bits;
+ bits = 0;
+ offset = 0;
+ }
+ /*
+ * If the next entry is going to be too big for the ocode size,
+ * then increase it, if possible.
+ */
+ if (free_ent > maxcode || (clear_flg > 0)) {
+ /*
+ * Write the whole buffer, because the input side won't
+ * discover the size increase until after it has read it.
+ */
+ if (offset > 0) {
+ if (fwrite(buf, 1, n_bits, fp) != n_bits)
+ return (-1);
+ bytes_out += n_bits;
+ }
+ offset = 0;
+
+ if (clear_flg) {
+ maxcode = MAXCODE(n_bits = INIT_BITS);
+ clear_flg = 0;
+ } else {
+ n_bits++;
+ if (n_bits == maxbits)
+ maxcode = maxmaxcode;
+ else
+ maxcode = MAXCODE(n_bits);
+ }
+ }
+ } else {
+ /* At EOF, write the rest of the buffer. */
+ if (offset > 0) {
+ offset = (offset + 7) / 8;
+ if (fwrite(buf, 1, offset, fp) != offset)
+ return (-1);
+ bytes_out += offset;
+ }
+ offset = 0;
+ }
+ return (0);
+}
+
+/*
+ * Decompress read. This routine adapts to the codes in the file building
+ * the "string" table on-the-fly; requiring no table to be stored in the
+ * compressed file. The tables used herein are shared with those of the
+ * compress() routine. See the definitions above.
+ */
+static int
+zread(cookie, rbp, num)
+ void *cookie;
+ char *rbp;
+ int num;
+{
+ register u_int count;
+ struct s_zstate *zs;
+ u_char *bp, header[3];
+
+ if (num == 0)
+ return (0);
+
+ zs = cookie;
+ count = num;
+ bp = (u_char *)rbp;
+ switch (state) {
+ case S_START:
+ state = S_MIDDLE;
+ break;
+ case S_MIDDLE:
+ goto middle;
+ case S_EOF:
+ goto eof;
+ }
+
+ /* Check the magic number */
+ if (fread(header,
+ sizeof(char), sizeof(header), fp) != sizeof(header) ||
+ memcmp(header, magic_header, sizeof(magic_header)) != 0) {
+ errno = EFTYPE;
+ return (-1);
+ }
+ maxbits = header[2]; /* Set -b from file. */
+ block_compress = maxbits & BLOCK_MASK;
+ maxbits &= BIT_MASK;
+ maxmaxcode = 1L << maxbits;
+ if (maxbits > BITS) {
+ errno = EFTYPE;
+ return (-1);
+ }
+ /* As above, initialize the first 256 entries in the table. */
+ maxcode = MAXCODE(n_bits = INIT_BITS);
+ for (code = 255; code >= 0; code--) {
+ tab_prefixof(code) = 0;
+ tab_suffixof(code) = (char_type) code;
+ }
+ free_ent = block_compress ? FIRST : 256;
+
+ finchar = oldcode = getcode(zs);
+ if (oldcode == -1) /* EOF already? */
+ return (0); /* Get out of here */
+
+ /* First code must be 8 bits = char. */
+ *bp++ = (u_char)finchar;
+ count--;
+ stackp = de_stack;
+
+ while ((code = getcode(zs)) > -1) {
+
+ if ((code == CLEAR) && block_compress) {
+ for (code = 255; code >= 0; code--)
+ tab_prefixof(code) = 0;
+ clear_flg = 1;
+ free_ent = FIRST - 1;
+ if ((code = getcode(zs)) == -1) /* O, untimely death! */
+ break;
+ }
+ incode = code;
+
+ /* Special case for KwKwK string. */
+ if (code >= free_ent) {
+ *stackp++ = finchar;
+ code = oldcode;
+ }
+
+ /* Generate output characters in reverse order. */
+ while (code >= 256) {
+ *stackp++ = tab_suffixof(code);
+ code = tab_prefixof(code);
+ }
+ *stackp++ = finchar = tab_suffixof(code);
+
+ /* And put them out in forward order. */
+middle: do {
+ if (count-- == 0)
+ return (num);
+ *bp++ = *--stackp;
+ } while (stackp > de_stack);
+
+ /* Generate the new entry. */
+ if ((code = free_ent) < maxmaxcode) {
+ tab_prefixof(code) = (u_short) oldcode;
+ tab_suffixof(code) = finchar;
+ free_ent = code + 1;
+ }
+
+ /* Remember previous code. */
+ oldcode = incode;
+ }
+ state = S_EOF;
+eof: return (num - count);
+}
+
+/*-
+ * Read one code from the standard input. If EOF, return -1.
+ * Inputs:
+ * stdin
+ * Outputs:
+ * code or -1 is returned.
+ */
+static code_int
+getcode(zs)
+ struct s_zstate *zs;
+{
+ register code_int gcode;
+ register int r_off, bits;
+ register char_type *bp;
+
+ bp = gbuf;
+ if (clear_flg > 0 || roffset >= size || free_ent > maxcode) {
+ /*
+ * If the next entry will be too big for the current gcode
+ * size, then we must increase the size. This implies reading
+ * a new buffer full, too.
+ */
+ if (free_ent > maxcode) {
+ n_bits++;
+ if (n_bits == maxbits) /* Won't get any bigger now. */
+ maxcode = maxmaxcode;
+ else
+ maxcode = MAXCODE(n_bits);
+ }
+ if (clear_flg > 0) {
+ maxcode = MAXCODE(n_bits = INIT_BITS);
+ clear_flg = 0;
+ }
+ size = fread(gbuf, 1, n_bits, fp);
+ if (size <= 0) /* End of file. */
+ return (-1);
+ roffset = 0;
+ /* Round size down to integral number of codes. */
+ size = (size << 3) - (n_bits - 1);
+ }
+ r_off = roffset;
+ bits = n_bits;
+
+ /* Get to the first byte. */
+ bp += (r_off >> 3);
+ r_off &= 7;
+
+ /* Get first part (low order bits). */
+ gcode = (*bp++ >> r_off);
+ bits -= (8 - r_off);
+ r_off = 8 - r_off; /* Now, roffset into gcode word. */
+
+ /* Get any 8 bit parts in the middle (<=1 for up to 16 bits). */
+ if (bits >= 8) {
+ gcode |= *bp++ << r_off;
+ r_off += 8;
+ bits -= 8;
+ }
+
+ /* High order bits. */
+ gcode |= (*bp & rmask[bits]) << r_off;
+ roffset += n_bits;
+
+ return (gcode);
+}
+
+static int
+cl_block(zs) /* Table clear for block compress. */
+ struct s_zstate *zs;
+{
+ register long rat;
+
+ checkpoint = in_count + CHECK_GAP;
+
+ if (in_count > 0x007fffff) { /* Shift will overflow. */
+ rat = bytes_out >> 8;
+ if (rat == 0) /* Don't divide by zero. */
+ rat = 0x7fffffff;
+ else
+ rat = in_count / rat;
+ } else
+ rat = (in_count << 8) / bytes_out; /* 8 fractional bits. */
+ if (rat > ratio)
+ ratio = rat;
+ else {
+ ratio = 0;
+ cl_hash(zs, (count_int) hsize);
+ free_ent = FIRST;
+ clear_flg = 1;
+ if (output(zs, (code_int) CLEAR) == -1)
+ return (-1);
+ }
+ return (0);
+}
+
+static void
+cl_hash(zs, cl_hsize) /* Reset code table. */
+ struct s_zstate *zs;
+ register count_int cl_hsize;
+{
+ register count_int *htab_p;
+ register long i, m1;
+
+ m1 = -1;
+ htab_p = htab + cl_hsize;
+ i = cl_hsize - 16;
+ do { /* Might use Sys V memset(3) here. */
+ *(htab_p - 16) = m1;
+ *(htab_p - 15) = m1;
+ *(htab_p - 14) = m1;
+ *(htab_p - 13) = m1;
+ *(htab_p - 12) = m1;
+ *(htab_p - 11) = m1;
+ *(htab_p - 10) = m1;
+ *(htab_p - 9) = m1;
+ *(htab_p - 8) = m1;
+ *(htab_p - 7) = m1;
+ *(htab_p - 6) = m1;
+ *(htab_p - 5) = m1;
+ *(htab_p - 4) = m1;
+ *(htab_p - 3) = m1;
+ *(htab_p - 2) = m1;
+ *(htab_p - 1) = m1;
+ htab_p -= 16;
+ } while ((i -= 16) >= 0);
+ for (i += 16; i > 0; i--)
+ *--htab_p = m1;
+}
+
+FILE *
+zopen(fname, mode, bits)
+ const char *fname, *mode;
+ int bits;
+{
+ struct s_zstate *zs;
+
+ if (mode[0] != 'r' && mode[0] != 'w' || mode[1] != '\0' ||
+ bits < 0 || bits > BITS) {
+ errno = EINVAL;
+ return (NULL);
+ }
+
+ if ((zs = calloc(1, sizeof(struct s_zstate))) == NULL)
+ return (NULL);
+
+ maxbits = bits ? bits : BITS; /* User settable max # bits/code. */
+ maxmaxcode = 1 << BITS; /* Should NEVER generate this code. */
+ hsize = HSIZE; /* For dynamic table sizing. */
+ free_ent = 0; /* First unused entry. */
+ block_compress = BLOCK_MASK;
+ clear_flg = 0;
+ ratio = 0;
+ checkpoint = CHECK_GAP;
+ in_count = 1; /* Length of input. */
+ out_count = 0; /* # of codes output (for debugging). */
+ state = S_START;
+ roffset = 0;
+ size = 0;
+
+ /*
+ * Layering compress on top of stdio in order to provide buffering,
+ * and ensure that reads and write work with the data specified.
+ */
+ if ((fp = fopen(fname, mode)) == NULL) {
+ free(zs);
+ return (NULL);
+ }
+ switch (*mode) {
+ case 'r':
+ zmode = 'r';
+ return (funopen(zs, zread, NULL, NULL, zclose));
+ case 'w':
+ zmode = 'w';
+ return (funopen(zs, NULL, zwrite, NULL, zclose));
+ }
+ /* NOTREACHED */
+}
generated by cgit v1.2.3 (git 2.25.1) at 2024-11-05 18:56:06 +0000