From dcb976fe4ee40e4bac8ae0dcc836629c625a6fd4 Mon Sep 17 00:00:00 2001
From: Christian Marangi <ansuelsmth@gmail.com>
Date: Fri, 14 Oct 2022 15:59:16 +0200
Subject: [PATCH] xz_wrapper: support multiple lzma configuration options

Add option to configure preset, lc, lp and pb lzma parameters.
-Xpreset can be used to set the compression level.
-Xe can be used to set the 'EXTREME' flag to use the lzma compression
options tweaking additional settings on top of the compression level set.

New option added:
 -Xpreset
 -Xe
 -Xlc
 -Xlp
 -Xpb

Signed-off-by: Christian Marangi <ansuelsmth@gmail.com>
---
 squashfs-tools/xz_wrapper.c | 119 ++++++++++++++++++++++++++++++++++--
 1 file changed, 115 insertions(+), 4 deletions(-)

--- a/squashfs-tools/xz_wrapper.c
+++ b/squashfs-tools/xz_wrapper.c
@@ -44,7 +44,10 @@ 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
@@ -53,6 +56,11 @@ static float dictionary_percent = 0;
  * Two specific options are supported:
  *	-Xbcj
  *	-Xdict-size
+ *	-Xpreset
+ *	-Xe
+ *	-Xlc
+ *	-Xlp
+ *	-Xpb
  *
  * This function returns:
  *	>=0 (number of additional args parsed) on success
@@ -141,6 +149,85 @@ 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;
@@ -446,11 +533,20 @@ 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, LZMA_PRESET_DEFAULT))
-                	goto failed;
+		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,
@@ -521,13 +617,28 @@ 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, "-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;