Allow 'gzip -d' and 'bzip2 -d' without gunzip or bunzip2

Idea copied from the "ip" applet.

Signed-off-by: Kang-Che Sung <explorer09@gmail.com>
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

archival/bbunzip.c

@@ -12,9 +12,9 @@
 //kbuild:lib-$(CONFIG_LZOPCAT) += bbunzip.o
 //kbuild:lib-$(CONFIG_UNLZOP) += bbunzip.o
 /* bzip2_main() too: */
-//kbuild:lib-$(CONFIG_BZIP2) += bbunzip.o
+//kbuild:lib-$(CONFIG_FEATURE_BZIP2_DECOMPRESS) += bbunzip.o
 /* gzip_main() too: */
-//kbuild:lib-$(CONFIG_GZIP) += bbunzip.o
+//kbuild:lib-$(CONFIG_FEATURE_GZIP_DECOMPRESS) += bbunzip.o
 
 /* Note: must be kept in sync with archival/lzop.c */
 enum {
@@ -197,7 +197,7 @@ int FAST_FUNC bbunpack(char **argv,
 }
 
 #if ENABLE_UNCOMPRESS \
- || ENABLE_BUNZIP2 || ENABLE_BZCAT \
+ || ENABLE_FEATURE_BZIP2_DECOMPRESS \
  || ENABLE_UNLZMA || ENABLE_LZCAT || ENABLE_LZMA \
  || ENABLE_UNXZ || ENABLE_XZCAT || ENABLE_XZ
 static
@@ -295,6 +295,7 @@ int uncompress_main(int argc UNUSED_PARAM, char **argv)
 //config:config GUNZIP
 //config:	bool "gunzip"
 //config:	default y
+//config:	select FEATURE_GZIP_DECOMPRESS
 //config:	help
 //config:	  gunzip is used to decompress archives created by gzip.
 //config:	  You can use the `-t' option to test the integrity of
@@ -303,6 +304,7 @@ int uncompress_main(int argc UNUSED_PARAM, char **argv)
 //config:config ZCAT
 //config:	bool "zcat"
 //config:	default y
+//config:	select FEATURE_GZIP_DECOMPRESS
 //config:	help
 //config:	  Alias to "gunzip -c".
 //config:
@@ -315,9 +317,7 @@ int uncompress_main(int argc UNUSED_PARAM, char **argv)
 
 //applet:IF_GUNZIP(APPLET(gunzip, BB_DIR_BIN, BB_SUID_DROP))
 //applet:IF_ZCAT(APPLET_ODDNAME(zcat, gunzip, BB_DIR_BIN, BB_SUID_DROP, zcat))
-//kbuild:lib-$(CONFIG_GUNZIP) += bbunzip.o
+#if ENABLE_FEATURE_GZIP_DECOMPRESS
-//kbuild:lib-$(CONFIG_ZCAT) += bbunzip.o
-#if ENABLE_GUNZIP || ENABLE_ZCAT
 static
 char* FAST_FUNC make_new_name_gunzip(char *filename, const char *expected_ext UNUSED_PARAM)
 {
@@ -385,7 +385,7 @@ int gunzip_main(int argc UNUSED_PARAM, char **argv)
 
 	return bbunpack(argv, unpack_gz_stream, make_new_name_gunzip, /*unused:*/ NULL);
 }
-#endif
+#endif /* FEATURE_GZIP_DECOMPRESS */
 
 
 /*
@@ -408,6 +408,7 @@ int gunzip_main(int argc UNUSED_PARAM, char **argv)
 //config:config BUNZIP2
 //config:	bool "bunzip2"
 //config:	default y
+//config:	select FEATURE_BZIP2_DECOMPRESS
 //config:	help
 //config:	  bunzip2 is a compression utility using the Burrows-Wheeler block
 //config:	  sorting text compression algorithm, and Huffman coding. Compression
@@ -421,14 +422,13 @@ int gunzip_main(int argc UNUSED_PARAM, char **argv)
 //config:config BZCAT
 //config:	bool "bzcat"
 //config:	default y
+//config:	select FEATURE_BZIP2_DECOMPRESS
 //config:	help
 //config:	  Alias to "bunzip2 -c".
 
 //applet:IF_BUNZIP2(APPLET(bunzip2, BB_DIR_USR_BIN, BB_SUID_DROP))
 //applet:IF_BZCAT(APPLET_ODDNAME(bzcat, bunzip2, BB_DIR_USR_BIN, BB_SUID_DROP, bzcat))
-//kbuild:lib-$(CONFIG_BUNZIP2) += bbunzip.o
+#if ENABLE_FEATURE_BZIP2_DECOMPRESS
-//kbuild:lib-$(CONFIG_BZCAT) += bbunzip.o
-#if ENABLE_BUNZIP2 || ENABLE_BZCAT
 int bunzip2_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
 int bunzip2_main(int argc UNUSED_PARAM, char **argv)
 {

archival/bzip2.c

@@ -19,6 +19,15 @@
 //config:
 //config:	  Unless you have a specific application which requires bzip2, you
 //config:	  should probably say N here.
+//config:
+//config:config FEATURE_BZIP2_DECOMPRESS
+//config:	bool "Enable decompression"
+//config:	default y
+//config:	depends on BZIP2 || BUNZIP2 || BZCAT
+//config:	help
+//config:	  Enable -d (--decompress) and -t (--test) options for bzip2.
+//config:	  This will be automatically selected if bunzip2 or bzcat is
+//config:	  enabled.
 
 //applet:IF_BZIP2(APPLET(bzip2, BB_DIR_USR_BIN, BB_SUID_DROP))
 //kbuild:lib-$(CONFIG_BZIP2) += bzip2.o
@@ -28,7 +37,10 @@
 //usage:#define bzip2_full_usage "\n\n"
 //usage:       "Compress FILEs (or stdin) with bzip2 algorithm\n"
 //usage:     "\n	-1..9	Compression level"
+//usage:	IF_FEATURE_BZIP2_DECOMPRESS(
 //usage:     "\n	-d	Decompress"
+//usage:     "\n	-t	Test file integrity"
+//usage:	)
 //usage:     "\n	-c	Write to stdout"
 //usage:     "\n	-f	Force"
 
@@ -184,8 +196,8 @@ int bzip2_main(int argc UNUSED_PARAM, char **argv)
 
 	opt_complementary = "s2"; /* -s means -2 (compatibility) */
 	/* Must match bbunzip's constants OPT_STDOUT, OPT_FORCE! */
-	opt = getopt32(argv, "cfv" IF_BUNZIP2("dt") "123456789qzs");
+	opt = getopt32(argv, "cfv" IF_FEATURE_BZIP2_DECOMPRESS("dt") "123456789qzs");
-#if ENABLE_BUNZIP2 /* bunzip2_main may not be visible... */
+#if ENABLE_FEATURE_BZIP2_DECOMPRESS /* bunzip2_main may not be visible... */
 	if (opt & 0x18) // -d and/or -t
 		return bunzip2_main(argc, argv);
 	opt >>= 5;

archival/gzip.c

@@ -72,19 +72,29 @@ aa:      85.1% -- replaced with aa.gz
 //config:	  is 6. If levels 1-3 are specified, 4 is used.
 //config:	  If this option is not selected, -N options are ignored and -9
 //config:	  is used.
+//config:
+//config:config FEATURE_GZIP_DECOMPRESS
+//config:	bool "Enable decompression"
+//config:	default y
+//config:	depends on GZIP || GUNZIP || ZCAT
+//config:	help
+//config:	  Enable -d (--decompress) and -t (--test) options for gzip.
+//config:	  This will be automatically selected if gunzip or zcat is
+//config:	  enabled.
 
 //applet:IF_GZIP(APPLET(gzip, BB_DIR_BIN, BB_SUID_DROP))
 //kbuild:lib-$(CONFIG_GZIP) += gzip.o
 
 //usage:#define gzip_trivial_usage
-//usage:       "[-cf" IF_GUNZIP("d") IF_FEATURE_GZIP_LEVELS("123456789") "] [FILE]..."
+//usage:       "[-cf" IF_FEATURE_GZIP_DECOMPRESS("dt") IF_FEATURE_GZIP_LEVELS("123456789") "] [FILE]..."
 //usage:#define gzip_full_usage "\n\n"
 //usage:       "Compress FILEs (or stdin)\n"
 //usage:	IF_FEATURE_GZIP_LEVELS(
 //usage:     "\n	-1..9	Compression level"
 //usage:	)
-//usage:	IF_GUNZIP(
+//usage:	IF_FEATURE_GZIP_DECOMPRESS(
 //usage:     "\n	-d	Decompress"
+//usage:     "\n	-t	Test file integrity"
 //usage:	)
 //usage:     "\n	-c	Write to stdout"
 //usage:     "\n	-f	Force"
@@ -2154,7 +2164,7 @@ static const char gzip_longopts[] ALIGN1 =
 	"to-stdout\0"           No_argument       "c"
 	"force\0"               No_argument       "f"
 	"verbose\0"             No_argument       "v"
-#if ENABLE_GUNZIP
+#if ENABLE_FEATURE_GZIP_DECOMPRESS
 	"decompress\0"          No_argument       "d"
 	"uncompress\0"          No_argument       "d"
 	"test\0"                No_argument       "t"
@@ -2181,7 +2191,7 @@ static const char gzip_longopts[] ALIGN1 =
  */
 
 int gzip_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
-#if ENABLE_GUNZIP
+#if ENABLE_FEATURE_GZIP_DECOMPRESS
 int gzip_main(int argc, char **argv)
 #else
 int gzip_main(int argc UNUSED_PARAM, char **argv)
@@ -2211,13 +2221,13 @@ int gzip_main(int argc UNUSED_PARAM, char **argv)
 	applet_long_options = gzip_longopts;
 #endif
 	/* Must match bbunzip's constants OPT_STDOUT, OPT_FORCE! */
-	opt = getopt32(argv, "cfv" IF_GUNZIP("dt") "qn123456789");
+	opt = getopt32(argv, "cfv" IF_FEATURE_GZIP_DECOMPRESS("dt") "qn123456789");
-#if ENABLE_GUNZIP /* gunzip_main may not be visible... */
+#if ENABLE_FEATURE_GZIP_DECOMPRESS /* gunzip_main may not be visible... */
 	if (opt & 0x18) // -d and/or -t
 		return gunzip_main(argc, argv);
 #endif
 #ifdef ENABLE_FEATURE_GZIP_LEVELS
-	opt >>= ENABLE_GUNZIP ? 7 : 5; /* drop cfv[dt]qn bits */
+	opt >>= ENABLE_FEATURE_GZIP_DECOMPRESS ? 7 : 5; /* drop cfv[dt]qn bits */
 	if (opt == 0)
 		opt = 1 << 6; /* default: 6 */
 	opt = ffs(opt >> 4); /* Maps -1..-4 to [0], -5 to [1] ... -9 to [5] */