xz: Add --single-stream.

This can be useful when there is garbage after the
compressed stream (.xz, .lzma, or raw stream).

Man page wasn't updated yet.

src/xz/args.c

@@ -68,6 +68,7 @@ parse_real(args_info *args, int argc, char **argv)
 		OPT_LZMA1,
 		OPT_LZMA2,
 
+		OPT_SINGLE_STREAM,
 		OPT_NO_SPARSE,
 		OPT_FILES,
 		OPT_FILES0,
@@ -94,6 +95,7 @@ parse_real(args_info *args, int argc, char **argv)
 		{ "force",        no_argument,       NULL,  'f' },
 		{ "stdout",       no_argument,       NULL,  'c' },
 		{ "to-stdout",    no_argument,       NULL,  'c' },
+		{ "single-stream", no_argument,      NULL,  OPT_SINGLE_STREAM },
 		{ "no-sparse",    no_argument,       NULL,  OPT_NO_SPARSE },
 		{ "suffix",       required_argument, NULL,  'S' },
 		// { "recursive",      no_argument,       NULL,  'r' }, // TODO
@@ -368,6 +370,10 @@ parse_real(args_info *args, int argc, char **argv)
 			break;
 		}
 
+		case OPT_SINGLE_STREAM:
+			opt_single_stream = true;
+			break;
+
 		case OPT_NO_SPARSE:
 			io_no_sparse();
 			break;

src/xz/coder.c

@@ -24,6 +24,7 @@ enum coder_init_ret {
 enum operation_mode opt_mode = MODE_COMPRESS;
 enum format_type opt_format = FORMAT_AUTO;
 bool opt_auto_adjust = true;
+bool opt_single_stream = false;
 
 
 /// Stream used to communicate with liblzma
@@ -366,8 +367,9 @@ coder_init(file_pair *pair)
 			break;
 		}
 	} else {
-		const uint32_t flags = LZMA_TELL_UNSUPPORTED_CHECK
+		uint32_t flags = LZMA_TELL_UNSUPPORTED_CHECK;
-				| LZMA_CONCATENATED;
+		if (!opt_single_stream)
+			flags |= LZMA_CONCATENATED;
 
 		// We abuse FORMAT_AUTO to indicate unknown file format,
 		// for which we may consider passthru mode.
@@ -518,6 +520,11 @@ coder_normal(file_pair *pair)
 			}
 
 			if (ret == LZMA_STREAM_END) {
+				if (opt_single_stream) {
+					success = true;
+					break;
+				}
+
 				// Check that there is no trailing garbage.
 				// This is needed for LZMA_Alone and raw
 				// streams.

src/xz/coder.h

@@ -41,6 +41,9 @@ extern enum format_type opt_format;
 /// they exceed the memory usage limit.
 extern bool opt_auto_adjust;
 
+/// If true, stop after decoding the first stream.
+extern bool opt_single_stream;
+
 
 /// Set the integrity check type used when compressing
 extern void coder_set_check(lzma_check check);

src/xz/message.c

@@ -1108,7 +1108,10 @@ message_help(bool long_help)
 "  -f, --force         force overwrite of output file and (de)compress links\n"
 "  -c, --stdout        write to standard output and don't delete input files"));
 
-	if (long_help)
+	if (long_help) {
+		puts(_(
+"      --single-stream decompress only the first stream, and silently\n"
+"                      ignore possible remaining input data"));
 		puts(_(
 "      --no-sparse     do not create sparse files when decompressing\n"
 "  -S, --suffix=.SUF   use the suffix `.SUF' on compressed files\n"
@@ -1116,6 +1119,7 @@ message_help(bool long_help)
 "                      omitted, filenames are read from the standard input;\n"
 "                      filenames must be terminated with the newline character\n"
 "      --files0[=FILE] like --files but use the null character as terminator"));
+	}
 
 	if (long_help) {
 		puts(_("\n Basic file format and compression options:\n"));