initial commit

SQUASHFS/squashfs-tools-4.4/squashfs-tools/zstd_wrapper.c

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+/*
+ * Copyright (c) 2017
+ * 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.
+ *
+ * zstd_wrapper.c
+ *
+ * Support for ZSTD compression http://zstd.net
+ */
+
+#include <stdio.h>
+#include <string.h>
+#include <stdlib.h>
+#include <zstd.h>
+#include <zstd_errors.h>
+
+#include "squashfs_fs.h"
+#include "zstd_wrapper.h"
+#include "compressor.h"
+
+static int compression_level = ZSTD_DEFAULT_COMPRESSION_LEVEL;
+
+/*
+ * This function is called by the options parsing code in mksquashfs.c
+ * to parse any -X compressor option.
+ *
+ * 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 zstd_dump_options() function is called later to get the options in
+ * a format suitable for writing to the filesystem.
+ */
+static int zstd_options(char *argv[], int argc)
+{
+	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 *zstd_dump_options(int block_size, int *size)
+{
+	return NULL;
+}
+
+/*
+ * 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 zstd_extract_options(int block_size, void *buffer, int size)
+{
+	struct zstd_comp_opts *comp_opts = buffer;
+
+	if (size == 0) {
+		/* Set default values */
+		compression_level = ZSTD_DEFAULT_COMPRESSION_LEVEL;
+		return 0;
+	}
+
+	/* we expect a comp_opts structure of sufficient size to be present */
+	if (size < sizeof(*comp_opts))
+		goto failed;
+
+	SQUASHFS_INSWAP_COMP_OPTS(comp_opts);
+
+	if (comp_opts->compression_level < 1) {
+		fprintf(stderr, "zstd: bad compression level in compression "
+			"options structure\n");
+		goto failed;
+	}
+
+	compression_level = comp_opts->compression_level;
+
+	return 0;
+
+failed:
+	fprintf(stderr, "zstd: error reading stored compressor options from "
+		"filesystem!\n");
+
+	return -1;
+}
+
+static void zstd_display_options(void *buffer, int size)
+{
+	struct zstd_comp_opts *comp_opts = buffer;
+
+	/* we expect a comp_opts structure of sufficient size to be present */
+	if (size < sizeof(*comp_opts))
+		goto failed;
+
+	SQUASHFS_INSWAP_COMP_OPTS(comp_opts);
+
+	if (comp_opts->compression_level < 1) {
+		fprintf(stderr, "zstd: bad compression level in compression "
+			"options structure\n");
+		goto failed;
+	}
+
+	printf("\tcompression-level %d\n", comp_opts->compression_level);
+
+	return;
+
+failed:
+	fprintf(stderr, "zstd: 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 zstd_init(void **strm, int block_size, int datablock)
+{
+	return 0;
+}
+
+static int zstd_compress(void *strm, void *dest, void *src, int size,
+			 int block_size, int *error)
+{
+    (void)strm;
+    (void)dest;
+    (void)src;
+    (void)size;
+    (void)block_size;
+    (void)error;
+	return 0;
+}
+
+static int zstd_uncompress(void *dest, void *src, int size, int outsize,
+			   int *error)
+{
+	const size_t res = ZSTD_decompress(dest, outsize, src, size);
+
+	if (ZSTD_isError(res)) {
+		fprintf(stderr, "\t%d %d\n", outsize, size);
+
+		*error = (int)ZSTD_getErrorCode(res);
+		return -1;
+	}
+
+	return (int)res;
+}
+
+static void zstd_usage(void)
+{
+	fprintf(stderr, "\t  -Xcompression-level <compression-level>\n");
+}
+
+struct compressor zstd_comp_ops = {
+	.init = zstd_init,
+	.compress = zstd_compress,
+	.uncompress = zstd_uncompress,
+	.options = zstd_options,
+	.dump_options = zstd_dump_options,
+	.extract_options = zstd_extract_options,
+	.display_options = zstd_display_options,
+	.usage = zstd_usage,
+	.id = ZSTD_COMPRESSION,
+	.name = "zstd",
+	.supported = 1
+};