From 5fb9fdfb8757fc9afb6318a3dcf9dce0a97de352 Mon Sep 17 00:00:00 2001
From: Phillip Lougher <phillip@squashfs.org.uk>
Date: Wed, 19 Apr 2023 18:35:53 +0100
Subject: [PATCH] xz_wrapper: make new OpenWrt extended options non-default

The reason why these options are being made non-default are
described here:

https://github.com/plougher/squashfs-tools/pull/218#issuecomment-1515197256

The new options can be enabled by editing the Makefile or by defining
XZ_EXTENDED_OPTIONS on the Make command line, e.g.

% CONFIG=1 XZ_SUPPORT=1 XZ_EXTENDED_OPTIONS=1 make

Signed-off-by: Phillip Lougher <phillip@squashfs.org.uk>
---
 squashfs-tools/Makefile              |  12 +
 squashfs-tools/xz_wrapper.c          | 117 +----
 squashfs-tools/xz_wrapper_extended.c | 664 +++++++++++++++++++++++++++
 3 files changed, 679 insertions(+), 114 deletions(-)
 create mode 100644 squashfs-tools/xz_wrapper_extended.c

--- a/squashfs-tools/Makefile
+++ b/squashfs-tools/Makefile
@@ -39,6 +39,10 @@ GZIP_SUPPORT = 1
 #
 #XZ_SUPPORT = 1
 
+# Enable support for OpenWrt extended compression options by uncommenting
+# next line.  Do not do this unless you understand the implications.
+#XZ_EXTENDED_OPTIONS = 1
+
 
 ############ Building LZO support ##############
 #
@@ -197,6 +201,7 @@ INSTALL_MANPAGES_DIR ?= $(INSTALL_PREFIX
 LZMA_XZ_SUPPORT ?= 0
 LZMA_SUPPORT ?= 0
 LZMA_DIR ?= ../../../../LZMA/lzma465
+XZ_EXTENDED_OPTIONS ?= 0
 endif
 
 
@@ -248,8 +253,13 @@ endif
 
 ifeq ($(XZ_SUPPORT),1)
 CFLAGS += -DXZ_SUPPORT
+ifeq ($(XZ_EXTENDED_OPTIONS),1)
+MKSQUASHFS_OBJS += xz_wrapper_extended.o
+UNSQUASHFS_OBJS += xz_wrapper_extended.o
+else
 MKSQUASHFS_OBJS += xz_wrapper.o
 UNSQUASHFS_OBJS += xz_wrapper.o
+endif
 LIBS += -llzma
 COMPRESSORS += xz
 endif
@@ -428,6 +438,8 @@ lz4_wrapper.o: lz4_wrapper.c squashfs_fs
 
 xz_wrapper.o: xz_wrapper.c squashfs_fs.h xz_wrapper.h compressor.h
 
+xz_wrapper_extended.o: xz_wrapper_extended.c squashfs_fs.h xz_wrapper.h compressor.h
+
 unsquashfs: $(UNSQUASHFS_OBJS)
 	$(CC) $(LDFLAGS) $(EXTRA_LDFLAGS) $(UNSQUASHFS_OBJS) $(LIBS) -o $@
 	ln -sf unsquashfs sqfscat
--- a/squashfs-tools/xz_wrapper.c
+++ b/squashfs-tools/xz_wrapper.c
@@ -44,10 +44,7 @@ static struct bcj bcj[] = {
 static int filter_count = 1;
 static int dictionary_size = 0;
 static float dictionary_percent = 0;
-static int preset = LZMA_PRESET_DEFAULT;
-static int lc = -1;
-static int lp = -1;
-static int pb = -1;
+
 
 /*
  * This function is called by the options parsing code in mksquashfs.c
@@ -56,11 +53,6 @@ static int pb = -1;
  * Two specific options are supported:
  *	-Xbcj
  *	-Xdict-size
- *	-Xpreset
- *	-Xe
- *	-Xlc
- *	-Xlp
- *	-Xpb
  *
  * This function returns:
  *	>=0 (number of additional args parsed) on success
@@ -149,85 +141,6 @@ static int xz_options(char *argv[], int
 		}
 
 		return 1;
-	} else if(strcmp(argv[0], "-Xpreset") == 0) {
-		char *b;
-		long val;
-
-		if(argc < 2) {
-			fprintf(stderr, "xz: -Xpreset missing preset-level "
-				"(valid value 0-9)\n");
-			goto failed;
-		}
-
-		val = strtol(argv[1], &b, 10);
-		if (*b != '\0' || (int) val < 0 || (int) val & ~LZMA_PRESET_LEVEL_MASK) {
-			fprintf(stderr, "xz: -Xpreset can't be "
-				"negative or more than the max preset\n");
-			goto failed;
-		}
-
-		preset &= ~LZMA_PRESET_LEVEL_MASK;
-		preset |= (int) val;
-
-		return 1;
-	} else if(strcmp(argv[0], "-Xe") == 0) {
-		preset |= LZMA_PRESET_EXTREME;
-
-		return 0;
-	} else if(strcmp(argv[0], "-Xlc") == 0) {
-		char *b;
-		long val;
-
-		if(argc < 2) {
-			fprintf(stderr, "xz: -Xlc missing value\n");
-			goto failed;
-		}
-
-		val = strtol(argv[1], &b, 10);
-		if (*b != '\0' || (int) val < LZMA_LCLP_MIN || (int) val > LZMA_LCLP_MAX) {
-			fprintf(stderr, "xz: -Xlc invalid value\n");
-			goto failed;
-		}
-
-		lc = (int) val;
-
-		return 1;
-	} else if(strcmp(argv[0], "-Xlp") == 0) {
-		char *b;
-		long val;
-
-		if(argc < 2) {
-			fprintf(stderr, "xz: -Xlp missing value\n");
-			goto failed;
-		}
-
-		val = strtol(argv[1], &b, 10);
-		if (*b != '\0' || (int) val < LZMA_LCLP_MIN || (int) val > LZMA_LCLP_MAX) {
-			fprintf(stderr, "xz: -Xlp invalid value\n");
-			goto failed;
-		}
-
-		lp = (int) val;
-
-		return 1;
-	} else if(strcmp(argv[0], "-Xpb") == 0) {
-		char *b;
-		long val;
-
-		if(argc < 2) {
-			fprintf(stderr, "xz: -Xpb missing value\n");
-			goto failed;
-		}
-
-		val = strtol(argv[1], &b, 10);
-		if (*b != '\0' || (int) val < LZMA_PB_MIN || (int) val > LZMA_PB_MAX) {
-			fprintf(stderr, "xz: -Xpb invalid value\n");
-			goto failed;
-		}
-
-		pb = (int) val;
-
-		return 1;
 	}
 
 	return -1;
@@ -533,20 +446,11 @@ static int xz_compress(void *strm, void
 	for(i = 0; i < stream->filters; i++) {
 		struct filter *filter = &stream->filter[i];
 
-		if(lzma_lzma_preset(&stream->opt, preset))
+		if(lzma_lzma_preset(&stream->opt, LZMA_PRESET_DEFAULT))
 			goto failed;
 
 		stream->opt.dict_size = stream->dictionary_size;
 
-		if (lc >= 0)
-			stream->opt.lc = lc;
-
-		if (lp >= 0)
-			stream->opt.lp = lp;
-
-		if (pb >= 0)
-			stream->opt.pb = pb;
-
 		filter->length = 0;
 		res = lzma_stream_buffer_encode(filter->filter,
 			LZMA_CHECK_CRC32, NULL, src, size, filter->buffer,
@@ -617,28 +521,13 @@ static void xz_usage(FILE *stream)
 	fprintf(stream, " header as either 2^n or as 2^n+2^(n+1).\n\t\t");
 	fprintf(stream, "Example dict-sizes are 75%%, 50%%, 37.5%%, 25%%, or");
 	fprintf(stream, " 32K, 16K, 8K\n\t\tetc.\n");
-	fprintf(stream, "\t  -Xpreset <preset-level>\n");
-	fprintf(stream, "\t\tUse <preset-value> as the custom preset to use");
-	fprintf(stream, " on compress.\n\t\t<preset-level> should be 0 .. 9");
-	fprintf(stream, " (default 6)\n");
-	fprintf(stream, "\t  -Xe\n");
-	fprintf(stream, "\t\tEnable additional compression settings by passing");
-	fprintf(stream, " the EXTREME\n\t\tflag to the compression flags.\n");
-	fprintf(stream, "\t  -Xlc <value>\n");
-	fprintf(stream, "\t  -Xlp <value>\n");
-	fprintf(stream, "\t  -Xpb <value>\n");
 }
 
 
 static int option_args(char *option)
 {
 	if(strcmp(option, "-Xbcj") == 0 ||
-	   strcmp(option, "-Xdict-size") == 0 ||
-	   strcmp(option, "-Xpreset") == 0 ||
-	   strcmp(option, "-Xe") == 0 ||
-	   strcmp(option, "-Xlc") == 0 ||
-	   strcmp(option, "-Xlp") == 0 ||
-	   strcmp(option, "-Xpb") == 0)
+				strcmp(option, "-Xdict-size") == 0)
 		return 1;
 
 	return 0;
--- /dev/null
+++ b/squashfs-tools/xz_wrapper_extended.c
@@ -0,0 +1,664 @@
+/*
+ * Copyright (c) 2010, 2011, 2012, 2013, 2021, 2022
+ * Phillip Lougher <phillip@squashfs.org.uk>
+ *
+ * This program 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,
+ * or (at your option) any later version.
+ *
+ * This program 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 this program; if not, write to the Free Software
+ * Foundation, 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
+ *
+ * xz_wrapper_extended.c
+ *
+ * Support for XZ (LZMA2) compression using XZ Utils liblzma
+ * http://tukaani.org/xz/
+ *
+ * This file supports OpenWrt extended XZ compression options.
+ */
+
+#include <stdio.h>
+#include <string.h>
+#include <stdlib.h>
+#include <lzma.h>
+
+#include "squashfs_fs.h"
+#include "xz_wrapper.h"
+#include "compressor.h"
+
+static struct bcj bcj[] = {
+	{ "x86", LZMA_FILTER_X86, 0 },
+	{ "powerpc", LZMA_FILTER_POWERPC, 0 },
+	{ "ia64", LZMA_FILTER_IA64, 0 },
+	{ "arm", LZMA_FILTER_ARM, 0 },
+	{ "armthumb", LZMA_FILTER_ARMTHUMB, 0 },
+	{ "sparc", LZMA_FILTER_SPARC, 0 },
+	{ NULL, LZMA_VLI_UNKNOWN, 0 }
+};
+
+static int filter_count = 1;
+static int dictionary_size = 0;
+static float dictionary_percent = 0;
+static int preset = LZMA_PRESET_DEFAULT;
+static int lc = -1;
+static int lp = -1;
+static int pb = -1;
+
+/*
+ * This function is called by the options parsing code in mksquashfs.c
+ * to parse any -X compressor option.
+ *
+ * Two specific options are supported:
+ *	-Xbcj
+ *	-Xdict-size
+ *	-Xpreset
+ *	-Xe
+ *	-Xlc
+ *	-Xlp
+ *	-Xpb
+ *
+ * This function returns:
+ *	>=0 (number of additional args parsed) on success
+ *	-1 if the option was unrecognised, or
+ *	-2 if the option was recognised, but otherwise bad in
+ *	   some way (e.g. invalid parameter)
+ *
+ * Note: this function sets internal compressor state, but does not
+ * pass back the results of the parsing other than success/failure.
+ * The xz_dump_options() function is called later to get the options in
+ * a format suitable for writing to the filesystem.
+ */
+static int xz_options(char *argv[], int argc)
+{
+	int i;
+	char *name;
+
+	if(strcmp(argv[0], "-Xbcj") == 0) {
+		if(argc < 2) {
+			fprintf(stderr, "xz: -Xbcj missing filter\n");
+			goto failed;
+		}
+
+		name = argv[1];
+		while(name[0] != '\0') {
+			for(i = 0; bcj[i].name; i++) {
+				int n = strlen(bcj[i].name);
+				if((strncmp(name, bcj[i].name, n) == 0) &&
+						(name[n] == '\0' ||
+						 name[n] == ',')) {
+					if(bcj[i].selected == 0) {
+						bcj[i].selected = 1;
+						filter_count++;
+					}
+					name += name[n] == ',' ? n + 1 : n;
+					break;
+				}
+			}
+			if(bcj[i].name == NULL) {
+				fprintf(stderr, "xz: -Xbcj unrecognised "
+					"filter\n");
+				goto failed;
+			}
+		}
+
+		return 1;
+	} else if(strcmp(argv[0], "-Xdict-size") == 0) {
+		char *b;
+		float size;
+
+		if(argc < 2) {
+			fprintf(stderr, "xz: -Xdict-size missing dict-size\n");
+			goto failed;
+		}
+
+		size = strtof(argv[1], &b);
+		if(*b == '%') {
+			if(size <= 0 || size > 100) {
+				fprintf(stderr, "xz: -Xdict-size percentage "
+					"should be 0 < dict-size <= 100\n");
+				goto failed;
+			}
+
+			dictionary_percent = size;
+			dictionary_size = 0;
+		} else {
+			if((float) ((int) size) != size) {
+				fprintf(stderr, "xz: -Xdict-size can't be "
+					"fractional unless a percentage of the"
+					" block size\n");
+				goto failed;
+			}
+
+			dictionary_percent = 0;
+			dictionary_size = (int) size;
+
+			if(*b == 'k' || *b == 'K')
+				dictionary_size *= 1024;
+			else if(*b == 'm' || *b == 'M')
+				dictionary_size *= 1024 * 1024;
+			else if(*b != '\0') {
+				fprintf(stderr, "xz: -Xdict-size invalid "
+					"dict-size\n");
+				goto failed;
+			}
+		}
+
+		return 1;
+	} else if(strcmp(argv[0], "-Xpreset") == 0) {
+		char *b;
+		long val;
+
+		if(argc < 2) {
+			fprintf(stderr, "xz: -Xpreset missing preset-level "
+				"(valid value 0-9)\n");
+			goto failed;
+		}
+
+		val = strtol(argv[1], &b, 10);
+		if (*b != '\0' || (int) val < 0 || (int) val & ~LZMA_PRESET_LEVEL_MASK) {
+			fprintf(stderr, "xz: -Xpreset can't be "
+				"negative or more than the max preset\n");
+			goto failed;
+		}
+
+		preset &= ~LZMA_PRESET_LEVEL_MASK;
+		preset |= (int) val;
+
+		return 1;
+	} else if(strcmp(argv[0], "-Xe") == 0) {
+		preset |= LZMA_PRESET_EXTREME;
+
+		return 0;
+	} else if(strcmp(argv[0], "-Xlc") == 0) {
+		char *b;
+		long val;
+
+		if(argc < 2) {
+			fprintf(stderr, "xz: -Xlc missing value\n");
+			goto failed;
+		}
+
+		val = strtol(argv[1], &b, 10);
+		if (*b != '\0' || (int) val < LZMA_LCLP_MIN || (int) val > LZMA_LCLP_MAX) {
+			fprintf(stderr, "xz: -Xlc invalid value\n");
+			goto failed;
+		}
+
+		lc = (int) val;
+
+		return 1;
+	} else if(strcmp(argv[0], "-Xlp") == 0) {
+		char *b;
+		long val;
+
+		if(argc < 2) {
+			fprintf(stderr, "xz: -Xlp missing value\n");
+			goto failed;
+		}
+
+		val = strtol(argv[1], &b, 10);
+		if (*b != '\0' || (int) val < LZMA_LCLP_MIN || (int) val > LZMA_LCLP_MAX) {
+			fprintf(stderr, "xz: -Xlp invalid value\n");
+			goto failed;
+		}
+
+		lp = (int) val;
+
+		return 1;
+	} else if(strcmp(argv[0], "-Xpb") == 0) {
+		char *b;
+		long val;
+
+		if(argc < 2) {
+			fprintf(stderr, "xz: -Xpb missing value\n");
+			goto failed;
+		}
+
+		val = strtol(argv[1], &b, 10);
+		if (*b != '\0' || (int) val < LZMA_PB_MIN || (int) val > LZMA_PB_MAX) {
+			fprintf(stderr, "xz: -Xpb invalid value\n");
+			goto failed;
+		}
+
+		pb = (int) val;
+
+		return 1;
+	}
+
+	return -1;
+
+failed:
+	return -2;
+}
+
+
+/*
+ * This function is called after all options have been parsed.
+ * It is used to do post-processing on the compressor options using
+ * values that were not expected to be known at option parse time.
+ *
+ * In this case block_size may not be known until after -Xdict-size has
+ * been processed (in the case where -b is specified after -Xdict-size)
+ *
+ * This function returns 0 on successful post processing, or
+ *			-1 on error
+ */
+static int xz_options_post(int block_size)
+{
+	/*
+	 * if -Xdict-size has been specified use this to compute the datablock
+	 * dictionary size
+	 */
+	if(dictionary_size || dictionary_percent) {
+		int n;
+
+		if(dictionary_size) {
+			if(dictionary_size > block_size) {
+				fprintf(stderr, "xz: -Xdict-size is larger than"
+				" block_size\n");
+				goto failed;
+			}
+		} else
+			dictionary_size = block_size * dictionary_percent / 100;
+
+		if(dictionary_size < 8192) {
+			fprintf(stderr, "xz: -Xdict-size should be 8192 bytes "
+				"or larger\n");
+			goto failed;
+		}
+
+		/*
+		 * dictionary_size must be storable in xz header as either
+		 * 2^n or as  2^n+2^(n+1)
+		 */
+		n = ffs(dictionary_size) - 1;
+		if(dictionary_size != (1 << n) &&
+				dictionary_size != ((1 << n) + (1 << (n + 1)))) {
+			fprintf(stderr, "xz: -Xdict-size is an unsupported "
+				"value, dict-size must be storable in xz "
+				"header\n");
+			fprintf(stderr, "as either 2^n or as 2^n+2^(n+1).  "
+				"Example dict-sizes are 75%%, 50%%, 37.5%%, "
+				"25%%,\n");
+			fprintf(stderr, "or 32K, 16K, 8K etc.\n");
+			goto failed;
+		}
+
+	} else
+		/* No -Xdict-size specified, use defaults */
+		dictionary_size = block_size;
+
+	return 0;
+
+failed:
+	return -1;
+}
+
+
+/*
+ * This function is called by mksquashfs to dump the parsed
+ * compressor options in a format suitable for writing to the
+ * compressor options field in the filesystem (stored immediately
+ * after the superblock).
+ *
+ * This function returns a pointer to the compression options structure
+ * to be stored (and the size), or NULL if there are no compression
+ * options
+ */
+static void *xz_dump_options(int block_size, int *size)
+{
+	static struct comp_opts comp_opts;
+	int flags = 0, i;
+
+	/*
+	 * don't store compressor specific options in file system if the
+	 * default options are being used - no compressor options in the
+	 * file system means the default options are always assumed
+	 *
+	 * Defaults are:
+	 *  metadata dictionary size: SQUASHFS_METADATA_SIZE
+	 *  datablock dictionary size: block_size
+	 *  1 filter
+	 */
+	if(dictionary_size == block_size && filter_count == 1)
+		return NULL;
+
+	for(i = 0; bcj[i].name; i++)
+		flags |= bcj[i].selected << i;
+
+	comp_opts.dictionary_size = dictionary_size;
+	comp_opts.flags = flags;
+
+	SQUASHFS_INSWAP_COMP_OPTS(&comp_opts);
+
+	*size = sizeof(comp_opts);
+	return &comp_opts;
+}
+
+
+/*
+ * This function is a helper specifically for the append mode of
+ * mksquashfs.  Its purpose is to set the internal compressor state
+ * to the stored compressor options in the passed compressor options
+ * structure.
+ *
+ * In effect this function sets up the compressor options
+ * to the same state they were when the filesystem was originally
+ * generated, this is to ensure on appending, the compressor uses
+ * the same compression options that were used to generate the
+ * original filesystem.
+ *
+ * Note, even if there are no compressor options, this function is still
+ * called with an empty compressor structure (size == 0), to explicitly
+ * set the default options, this is to ensure any user supplied
+ * -X options on the appending mksquashfs command line are over-ridden
+ *
+ * This function returns 0 on sucessful extraction of options, and
+ *			-1 on error
+ */
+static int xz_extract_options(int block_size, void *buffer, int size)
+{
+	struct comp_opts *comp_opts = buffer;
+	int flags, i, n;
+
+	if(size == 0) {
+		/* set defaults */
+		dictionary_size = block_size;
+		flags = 0;
+	} else {
+		/* check passed comp opts struct is of the correct length */
+		if(size != sizeof(struct comp_opts))
+			goto failed;
+
+		SQUASHFS_INSWAP_COMP_OPTS(comp_opts);
+
+		dictionary_size = comp_opts->dictionary_size;
+		flags = comp_opts->flags;
+
+		/*
+		 * check that the dictionary size seems correct - the dictionary
+		 * size should 2^n or 2^n+2^(n+1)
+		 */
+		n = ffs(dictionary_size) - 1;
+		if(dictionary_size != (1 << n) &&
+				dictionary_size != ((1 << n) + (1 << (n + 1))))
+			goto failed;
+	}
+
+	filter_count = 1;
+	for(i = 0; bcj[i].name; i++) {
+		if((flags >> i) & 1) {
+			bcj[i].selected = 1;
+			filter_count ++;
+		} else
+			bcj[i].selected = 0;
+	}
+
+	return 0;
+
+failed:
+	fprintf(stderr, "xz: error reading stored compressor options from "
+		"filesystem!\n");
+
+	return -1;
+}
+
+
+static void xz_display_options(void *buffer, int size)
+{
+	struct comp_opts *comp_opts = buffer;
+	int dictionary_size, flags, printed;
+	int i, n;
+
+	/* check passed comp opts struct is of the correct length */
+	if(size != sizeof(struct comp_opts))
+		goto failed;
+
+	SQUASHFS_INSWAP_COMP_OPTS(comp_opts);
+
+	dictionary_size = comp_opts->dictionary_size;
+	flags = comp_opts->flags;
+
+	/*
+	 * check that the dictionary size seems correct - the dictionary
+	 * size should 2^n or 2^n+2^(n+1)
+	 */
+	n = ffs(dictionary_size) - 1;
+	if(dictionary_size != (1 << n) &&
+			dictionary_size != ((1 << n) + (1 << (n + 1))))
+		goto failed;
+
+	printf("\tDictionary size %d\n", dictionary_size);
+
+	printed = 0;
+	for(i = 0; bcj[i].name; i++) {
+		if((flags >> i) & 1) {
+			if(printed)
+				printf(", ");
+			else
+				printf("\tFilters selected: ");
+			printf("%s", bcj[i].name);
+			printed = 1;
+		}
+	}
+
+	if(!printed)
+		printf("\tNo filters specified\n");
+	else
+		printf("\n");
+
+	return;
+
+failed:
+	fprintf(stderr, "xz: error reading stored compressor options from "
+		"filesystem!\n");
+}
+
+
+/*
+ * This function is called by mksquashfs to initialise the
+ * compressor, before compress() is called.
+ *
+ * This function returns 0 on success, and
+ *			-1 on error
+ */
+static int xz_init(void **strm, int block_size, int datablock)
+{
+	int i, j, filters = datablock ? filter_count : 1;
+	struct filter *filter = malloc(filters * sizeof(struct filter));
+	struct xz_stream *stream;
+
+	if(filter == NULL)
+		goto failed;
+
+	stream = *strm = malloc(sizeof(struct xz_stream));
+	if(stream == NULL)
+		goto failed2;
+
+	stream->filter = filter;
+	stream->filters = filters;
+
+	memset(filter, 0, filters * sizeof(struct filter));
+
+	stream->dictionary_size = datablock ? dictionary_size :
+		SQUASHFS_METADATA_SIZE;
+
+	filter[0].filter[0].id = LZMA_FILTER_LZMA2;
+	filter[0].filter[0].options = &stream->opt;
+	filter[0].filter[1].id = LZMA_VLI_UNKNOWN;
+
+	for(i = 0, j = 1; datablock && bcj[i].name; i++) {
+		if(bcj[i].selected) {
+			filter[j].buffer = malloc(block_size);
+			if(filter[j].buffer == NULL)
+				goto failed3;
+			filter[j].filter[0].id = bcj[i].id;
+			filter[j].filter[1].id = LZMA_FILTER_LZMA2;
+			filter[j].filter[1].options = &stream->opt;
+			filter[j].filter[2].id = LZMA_VLI_UNKNOWN;
+			j++;
+		}
+	}
+
+	return 0;
+
+failed3:
+	for(i = 1; i < filters; i++)
+		free(filter[i].buffer);
+	free(stream);
+
+failed2:
+	free(filter);
+
+failed:
+	return -1;
+}
+
+
+static int xz_compress(void *strm, void *dest, void *src,  int size,
+	int block_size, int *error)
+{
+	int i;
+        lzma_ret res = 0;
+	struct xz_stream *stream = strm;
+	struct filter *selected = NULL;
+
+	stream->filter[0].buffer = dest;
+
+	for(i = 0; i < stream->filters; i++) {
+		struct filter *filter = &stream->filter[i];
+
+		if(lzma_lzma_preset(&stream->opt, preset))
+			goto failed;
+
+		stream->opt.dict_size = stream->dictionary_size;
+
+		if (lc >= 0)
+			stream->opt.lc = lc;
+
+		if (lp >= 0)
+			stream->opt.lp = lp;
+
+		if (pb >= 0)
+			stream->opt.pb = pb;
+
+		filter->length = 0;
+		res = lzma_stream_buffer_encode(filter->filter,
+			LZMA_CHECK_CRC32, NULL, src, size, filter->buffer,
+			&filter->length, block_size);
+
+		if(res == LZMA_OK) {
+			if(!selected || selected->length > filter->length)
+				selected = filter;
+		} else if(res != LZMA_BUF_ERROR)
+			goto failed;
+	}
+
+	if(!selected)
+		/*
+		 * Output buffer overflow.  Return out of buffer space
+		 */
+		return 0;
+
+	if(selected->buffer != dest)
+		memcpy(dest, selected->buffer, selected->length);
+
+	return (int) selected->length;
+
+failed:
+	/*
+	 * All other errors return failure, with the compressor
+	 * specific error code in *error
+	 */
+	*error = res;
+	return -1;
+}
+
+
+static int xz_uncompress(void *dest, void *src, int size, int outsize,
+	int *error)
+{
+	size_t src_pos = 0;
+	size_t dest_pos = 0;
+	uint64_t memlimit = MEMLIMIT;
+
+	lzma_ret res = lzma_stream_buffer_decode(&memlimit, 0, NULL,
+			src, &src_pos, size, dest, &dest_pos, outsize);
+
+	if(res == LZMA_OK && size == (int) src_pos)
+		return (int) dest_pos;
+	else {
+		*error = res;
+		return -1;
+	}
+}
+
+
+static void xz_usage(FILE *stream)
+{
+	fprintf(stream, "\t  -Xbcj filter1,filter2,...,filterN\n");
+	fprintf(stream, "\t\tCompress using filter1,filter2,...,filterN in");
+	fprintf(stream, " turn\n\t\t(in addition to no filter), and choose");
+	fprintf(stream, " the best compression.\n");
+	fprintf(stream, "\t\tAvailable filters: x86, arm, armthumb,");
+	fprintf(stream, " powerpc, sparc, ia64\n");
+	fprintf(stream, "\t  -Xdict-size <dict-size>\n");
+	fprintf(stream, "\t\tUse <dict-size> as the XZ dictionary size.  The");
+	fprintf(stream, " dictionary size\n\t\tcan be specified as a");
+	fprintf(stream, " percentage of the block size, or as an\n\t\t");
+	fprintf(stream, "absolute value.  The dictionary size must be less");
+	fprintf(stream, " than or equal\n\t\tto the block size and 8192 bytes");
+	fprintf(stream, " or larger.  It must also be\n\t\tstorable in the xz");
+	fprintf(stream, " header as either 2^n or as 2^n+2^(n+1).\n\t\t");
+	fprintf(stream, "Example dict-sizes are 75%%, 50%%, 37.5%%, 25%%, or");
+	fprintf(stream, " 32K, 16K, 8K\n\t\tetc.\n");
+	fprintf(stream, "\t  -Xpreset <preset-level>\n");
+	fprintf(stream, "\t\tUse <preset-value> as the custom preset to use");
+	fprintf(stream, " on compress.\n\t\t<preset-level> should be 0 .. 9");
+	fprintf(stream, " (default 6)\n");
+	fprintf(stream, "\t  -Xe\n");
+	fprintf(stream, "\t\tEnable additional compression settings by passing");
+	fprintf(stream, " the EXTREME\n\t\tflag to the compression flags.\n");
+	fprintf(stream, "\t  -Xlc <value>\n");
+	fprintf(stream, "\t  -Xlp <value>\n");
+	fprintf(stream, "\t  -Xpb <value>\n");
+}
+
+
+static int option_args(char *option)
+{
+	if(strcmp(option, "-Xbcj") == 0 ||
+	   strcmp(option, "-Xdict-size") == 0 ||
+	   strcmp(option, "-Xpreset") == 0 ||
+	   strcmp(option, "-Xe") == 0 ||
+	   strcmp(option, "-Xlc") == 0 ||
+	   strcmp(option, "-Xlp") == 0 ||
+	   strcmp(option, "-Xpb") == 0)
+		return 1;
+
+	return 0;
+}
+
+
+struct compressor xz_comp_ops = {
+	.init = xz_init,
+	.compress = xz_compress,
+	.uncompress = xz_uncompress,
+	.options = xz_options,
+	.options_post = xz_options_post,
+	.dump_options = xz_dump_options,
+	.extract_options = xz_extract_options,
+	.display_options = xz_display_options,
+	.usage = xz_usage,
+	.option_args = option_args,
+	.id = XZ_COMPRESSION,
+	.name = "xz",
+	.supported = 1
+};