Move compression file name utilities to lib/

This makes more sense as a home for plain file name manipulation
utilities.  I also merged `include/comp_src.h.in` into
`lib/compression.c`, because structure definitions (as opposed to
declarations) don't belong in header files.

* src/compression.c: Move to ...
* lib/compression.c: ... here.  Remove unnecessary `pipeline.h` include.
* src/compression.h: Move to ...
* lib/compression.h: ... here.  Update positioning of all includes.
* lib/Makefile.am (libman_la_SOURCES): Add `compression.c` and
`compression.h`.
* lib/README: Add `compression.*`.
* src/Makefile.am (lexgrog_SOURCES, man_SOURCES, man_recode_SOURCES,
mandb_SOURCES): Remove `compression.c` and `compression.h`.

* include/comp_src.h (comp_list): Move to ...
* lib/compression.c (comp_list): ... here.  Update all references.
* include/manconfig.h (struct compression, comp_list): Move to ...
* lib/compression.h (struct compression, comp_list): ... here.  Add
includes where necessary.
* Makefile.am (noinst_HEADERS): Remove `include/comp_src.h`.

10 files changed, 14 insertions, 170 deletions

diff --git a/src/Makefile.am b/src/Makefile.am
index 7d4a398b..c92c852b 100644
--- a/src/Makefile.am
+++ b/src/Makefile.am
@@ -84,8 +84,6 @@ globbing_SOURCES = \
 	globbing.h \
 	globbing_test.c
 lexgrog_SOURCES = \
-	compression.c \
-	compression.h \
 	convert.c \
 	convert.h \
 	decompress.c \
@@ -108,8 +106,6 @@ lexgrog_SOURCES = \
 	utf8.c \
 	utf8.h
 man_SOURCES = \
-	compression.c \
-	compression.h \
 	decompress.c \
 	decompress.h \
 	filenames.c \
@@ -130,8 +126,6 @@ man_SOURCES = \
 	zsoelim.h \
 	zsoelim.l
 man_recode_SOURCES = \
-	compression.c \
-	compression.h \
 	decompress.c \
 	decompress.h \
 	man-recode.c \
@@ -150,8 +144,6 @@ manconv_SOURCES = \
 mandb_SOURCES = \
 	check_mandirs.c \
 	check_mandirs.h \
-	compression.c \
-	compression.h \
 	decompress.c \
 	decompress.h \
 	descriptions.c \
diff --git a/src/compression.c b/src/compression.c
deleted file mode 100644
index ba509545..00000000
--- a/src/compression.c
+++ /dev/null
@@ -1,128 +0,0 @@
-/*
- * compression.c: code to find decompressor / compression extension
- *
- * Copyright (C) 1994, 1995 Graeme W. Wilford. (Wilf.)
- * Copyright (C) 2001, 2002 Colin Watson.
- *
- * This file is part of man-db.
- *
- * man-db is free software; you can redistribute it and/or modify it
- * under the terms of the GNU General Public License as published by
- * the Free Software Foundation; either version 2 of the License, or
- * (at your option) any later version.
- *
- * man-db is distributed in the hope that it will be useful, but
- * WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- * GNU General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with man-db; if not, write to the Free Software Foundation,
- * Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
- *
- * Sat Aug 20 15:01:02 BST 1994  Wilf. (G.Wilford@ee.surrey.ac.uk)
- */
-
-#ifdef HAVE_CONFIG_H
-#  include "config.h"
-#endif /* HAVE_CONFIG_H */
-
-#include <assert.h>
-#include <stdio.h>
-#include <errno.h>
-#include <signal.h>
-#include <string.h>
-#include <stdlib.h>
-#include <unistd.h>
-#include <sys/types.h>
-#include <sys/stat.h>
-#include <fcntl.h>
-
-#include "error.h"
-#include "xstrndup.h"
-#include "xvasprintf.h"
-
-#include "manconfig.h"
-
-#include "pipeline.h"
-
-#include "appendstr.h"
-
-#include "compression.h"
-
-/* Take filename as arg, return structure containing decompressor
-   and extension, or NULL if no comp extension found.
-   If want_stem, set comp->stem to the filename without extension, which
-   the caller should free.
-
-   eg.
-   	filename = /usr/man/man1/foo.1.gz
-
-	comp->prog = "/usr/bin/gzip -dc";
-   	comp->ext = "gz";
-   	comp->stem = "/usr/man/man1/foo.1";
- */
-struct compression *comp_info (const char *filename, int want_stem)
-{
-	const char *ext;
-	static struct compression hpux_comp =
-		{PROG_GUNZIP " -S \"\"", "", NULL};
-
-	ext = strrchr (filename, '.');
-
-	if (ext) {
-		struct compression *comp;
-		for (comp = comp_list; comp->ext; comp++) {
-			if (strcmp (comp->ext, ext + 1) == 0) {
-				if (want_stem)
-					comp->stem = xstrndup (filename,
-							       ext - filename);
-				else
-					comp->stem = NULL;
-				return comp;
-			}
-		}
-	}
-
-	if (*PROG_GUNZIP) {
-		ext = strstr (filename, ".Z/");
-		if (ext) {
-			if (want_stem)
-				hpux_comp.stem = xstrndup (filename,
-							   ext - filename);
-			else
-				hpux_comp.stem = NULL;
-			return &hpux_comp;
-		}
-	}
-
-	return NULL;
-}
-
-/* take filename w/o comp ext. as arg, return comp->stem as a relative
-   compressed file or NULL if none found */
-struct compression *comp_file (const char *filename)
-{
-	size_t len;
-	char *compfile;
-	struct compression *comp;
-
-	compfile = xasprintf ("%s.", filename);
-	assert (compfile);
-	len = strlen (compfile);
-
-	for (comp = comp_list; comp->ext; comp++) {
-		struct stat buf;
-
-		compfile = appendstr (compfile, comp->ext, (void *) 0);
-
-		if (stat (compfile, &buf) == 0) {
-			comp->stem = compfile;
-			return comp;
-		}
-
-		*(compfile + len) = '\0';
-	}
-	free (compfile);
-	return NULL;
-}
diff --git a/src/compression.h b/src/compression.h
deleted file mode 100644
index 3ff0f895..00000000
--- a/src/compression.h
+++ /dev/null
@@ -1,25 +0,0 @@
-/*
- * compression.h: interface to finding decompressor / compression extension
- *
- * Copyright (C) 1994, 1995 Graeme W. Wilford. (Wilf.)
- * Copyright (C) 2001-2022 Colin Watson.
- *
- * This file is part of man-db.
- *
- * man-db is free software; you can redistribute it and/or modify it
- * under the terms of the GNU General Public License as published by
- * the Free Software Foundation; either version 2 of the License, or
- * (at your option) any later version.
- *
- * man-db is distributed in the hope that it will be useful, but
- * WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- * GNU General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with man-db; if not, write to the Free Software Foundation,
- * Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
- */
-
-extern struct compression *comp_info (const char *filename, int want_stem);
-extern struct compression *comp_file (const char *filename);
diff --git a/src/decompress.c b/src/decompress.c
index b8e95b05..c4832410 100644
--- a/src/decompress.c
+++ b/src/decompress.c
@@ -38,6 +38,8 @@
 #  include "zlib.h"
 #endif /* HAVE_LIBZ */
 
+#include "pipeline.h"
+
 #include "attribute.h"
 #include "minmax.h"
 #include "xalloc.h"
@@ -45,11 +47,12 @@
 #include "xvasprintf.h"
 
 #include "manconfig.h"
-#include "comp_src.h"
-#include "pipeline.h"
-#include "decompress.h"
+
+#include "compression.h"
 #include "sandbox.h"
 
+#include "decompress.h"
+
 enum decompress_tag {
 	DECOMPRESS_PIPELINE,
 	DECOMPRESS_INPROCESS
diff --git a/src/filenames.c b/src/filenames.c
index cbeb49cc..83e09069 100644
--- a/src/filenames.c
+++ b/src/filenames.c
@@ -39,11 +39,11 @@
 #include "manconfig.h"
 
 #include "appendstr.h"
+#include "compression.h"
 #include "debug.h"
 
 #include "db_storage.h"
 
-#include "compression.h"
 #include "filenames.h"
 
 static void gripe_bogus_manpage (const char *manpage)
diff --git a/src/man-recode.c b/src/man-recode.c
index 9d59bfa1..4cd0aaf3 100644
--- a/src/man-recode.c
+++ b/src/man-recode.c
@@ -52,6 +52,7 @@
 #include "pipeline.h"
 
 #include "cleanup.h"
+#include "compression.h"
 #include "debug.h"
 #include "encodings.h"
 #include "fatal.h"
@@ -59,7 +60,6 @@
 #include "sandbox.h"
 #include "util.h"
 
-#include "compression.h"
 #include "decompress.h"
 #include "manconv.h"
 #include "manconv_client.h"
diff --git a/src/man.c b/src/man.c
index 7f0d7bce..456968dd 100644
--- a/src/man.c
+++ b/src/man.c
@@ -86,6 +86,7 @@
 
 #include "appendstr.h"
 #include "cleanup.h"
+#include "compression.h"
 #include "debug.h"
 #include "fatal.h"
 #include "glcontainers.h"
@@ -104,7 +105,6 @@
 #include "mydbm.h"
 #include "db_storage.h"
 
-#include "compression.h"
 #include "filenames.h"
 #include "globbing.h"
 #include "ult_src.h"
diff --git a/src/straycats.c b/src/straycats.c
index 1315345b..75cacdd1 100644
--- a/src/straycats.c
+++ b/src/straycats.c
@@ -53,6 +53,7 @@
 #include "manconfig.h"
 
 #include "appendstr.h"
+#include "compression.h"
 #include "debug.h"
 #include "glcontainers.h"
 #include "pipeline.h"
@@ -66,7 +67,6 @@
 #include "mydbm.h"
 #include "db_storage.h"
 
-#include "compression.h"
 #include "descriptions.h"
 #include "lexgrog.h"
 #include "manp.h"
diff --git a/src/ult_src.c b/src/ult_src.c
index 69afb712..407360f3 100644
--- a/src/ult_src.c
+++ b/src/ult_src.c
@@ -56,9 +56,9 @@
 
 #include "manconfig.h"
 
+#include "compression.h"
 #include "debug.h"
 
-#include "compression.h"
 #include "decompress.h"
 #include "globbing.h"
 #include "ult_src.h"
diff --git a/src/zsoelim.l b/src/zsoelim.l
index 845f6f44..2d11660f 100644
--- a/src/zsoelim.l
+++ b/src/zsoelim.l
@@ -83,10 +83,12 @@
 #define _(String) gettext (String)
 
 #include "appendstr.h"
+#include "compression.h"
 #include "debug.h"
-#include "decompress.h"
 #include "fatal.h"
 #include "glcontainers.h"
+
+#include "decompress.h"
 #include "globbing.h"
 #include "zsoelim.h"