Add support for specifying the BCJ filter start offset

in the xz command line tool.

src/xz/args.c

@@ -80,15 +80,15 @@ parse_real(args_info *args, int argc, char **argv)
 		// Filters
 		{ "lzma1",          optional_argument, NULL,  OPT_LZMA1 },
 		{ "lzma2",          optional_argument, NULL,  OPT_LZMA2 },
-		{ "x86",            no_argument,       NULL,  OPT_X86 },
+		{ "x86",            optional_argument, NULL,  OPT_X86 },
-		{ "bcj",            no_argument,       NULL,  OPT_X86 },
+		{ "bcj",            optional_argument, NULL,  OPT_X86 },
-		{ "powerpc",        no_argument,       NULL,  OPT_POWERPC },
+		{ "powerpc",        optional_argument, NULL,  OPT_POWERPC },
-		{ "ppc",            no_argument,       NULL,  OPT_POWERPC },
+		{ "ppc",            optional_argument, NULL,  OPT_POWERPC },
-		{ "ia64",           no_argument,       NULL,  OPT_IA64 },
+		{ "ia64",           optional_argument, NULL,  OPT_IA64 },
-		{ "itanium",        no_argument,       NULL,  OPT_IA64 },
+		{ "itanium",        optional_argument, NULL,  OPT_IA64 },
-		{ "arm",            no_argument,       NULL,  OPT_ARM },
+		{ "arm",            optional_argument, NULL,  OPT_ARM },
-		{ "armthumb",       no_argument,       NULL,  OPT_ARMTHUMB },
+		{ "armthumb",       optional_argument, NULL,  OPT_ARMTHUMB },
-		{ "sparc",          no_argument,       NULL,  OPT_SPARC },
+		{ "sparc",          optional_argument, NULL,  OPT_SPARC },
 		{ "delta",          optional_argument, NULL,  OPT_DELTA },
 		{ "subblock",       optional_argument, NULL,  OPT_SUBBLOCK },
 
@@ -222,27 +222,33 @@ parse_real(args_info *args, int argc, char **argv)
 			break;
 
 		case OPT_X86:
-			coder_add_filter(LZMA_FILTER_X86, NULL);
+			coder_add_filter(LZMA_FILTER_X86,
+					options_bcj(optarg));
 			break;
 
 		case OPT_POWERPC:
-			coder_add_filter(LZMA_FILTER_POWERPC, NULL);
+			coder_add_filter(LZMA_FILTER_POWERPC,
+					options_bcj(optarg));
 			break;
 
 		case OPT_IA64:
-			coder_add_filter(LZMA_FILTER_IA64, NULL);
+			coder_add_filter(LZMA_FILTER_IA64,
+					options_bcj(optarg));
 			break;
 
 		case OPT_ARM:
-			coder_add_filter(LZMA_FILTER_ARM, NULL);
+			coder_add_filter(LZMA_FILTER_ARM,
+					options_bcj(optarg));
 			break;
 
 		case OPT_ARMTHUMB:
-			coder_add_filter(LZMA_FILTER_ARMTHUMB, NULL);
+			coder_add_filter(LZMA_FILTER_ARMTHUMB,
+					options_bcj(optarg));
 			break;
 
 		case OPT_SPARC:
-			coder_add_filter(LZMA_FILTER_SPARC, NULL);
+			coder_add_filter(LZMA_FILTER_SPARC,
+					options_bcj(optarg));
 			break;
 
 		case OPT_DELTA:

src/xz/message.c

@@ -1101,12 +1101,14 @@ message_help(bool long_help)
 
 		puts(_(
 "\n"
-"  --x86               x86 filter (sometimes called BCJ filter)\n"
+"  --x86[=OPTS]        x86 BCJ filter\n"
-"  --powerpc           PowerPC (big endian) filter\n"
+"  --powerpc[=OPTS]    PowerPC BCJ filter (big endian only)\n"
-"  --ia64              IA64 (Itanium) filter\n"
+"  --ia64[=OPTS]       IA64 (Itanium) BCJ filter\n"
-"  --arm               ARM filter\n"
+"  --arm[=OPTS]        ARM BCJ filter (little endian only)\n"
-"  --armthumb          ARM-Thumb filter\n"
+"  --armthumb[=OPTS]   ARM-Thumb BCJ filter (little endian only)\n"
-"  --sparc             SPARC filter"));
+"  --sparc[=OPTS]      SPARC BCJ filter\n"
+"                      Valid OPTS for all BCJ filters:\n"
+"                        start=NUM  start offset for conversions (default=0)"));
 
 #if defined(HAVE_ENCODER_DELTA) || defined(HAVE_DECODER_DELTA)
 		puts(_(

src/xz/options.c

@@ -225,6 +225,46 @@ options_delta(const char *str)
 }
 
 
+/////////
+// BCJ //
+/////////
+
+enum {
+	OPT_START_OFFSET,
+};
+
+
+static void
+set_bcj(void *options, uint32_t key, uint64_t value)
+{
+	lzma_options_bcj *opt = options;
+	switch (key) {
+	case OPT_START_OFFSET:
+		opt->start_offset = value;
+		break;
+	}
+}
+
+
+extern lzma_options_bcj *
+options_bcj(const char *str)
+{
+	static const option_map opts[] = {
+		{ "start",    NULL,  0, UINT32_MAX },
+		{ NULL,       NULL,  0, 0 }
+	};
+
+	lzma_options_bcj *options = xmalloc(sizeof(lzma_options_bcj));
+	*options = (lzma_options_bcj){
+		.start_offset = 0,
+	};
+
+	parse_options(str, opts, &set_bcj, options);
+
+	return options;
+}
+
+
 //////////
 // LZMA //
 //////////

src/xz/options.h

@@ -24,6 +24,13 @@ extern lzma_options_subblock *options_subblock(const char *str);
 extern lzma_options_delta *options_delta(const char *str);
 
 
+/// \brief      Parser for BCJ options
+///
+/// \return     Pointer to allocated options structure.
+///             Doesn't return on error.
+extern lzma_options_bcj *options_bcj(const char *str);
+
+
 /// \brief      Parser for LZMA options
 ///
 /// \return     Pointer to allocated options structure.