From 1cdea92b11ae260a8223f08e1e71e7487906f2f2 Mon Sep 17 00:00:00 2001
From: David Oberhollenzer <david.oberhollenzer@sigma-star.at>
Date: Mon, 6 May 2019 12:02:47 +0200
Subject: Add lz4 compressor implementation

Signed-off-by: David Oberhollenzer <david.oberhollenzer@sigma-star.at>
---
 lib/comp/lz4.c | 106 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 106 insertions(+)
 create mode 100644 lib/comp/lz4.c

(limited to 'lib/comp/lz4.c')

diff --git a/lib/comp/lz4.c b/lib/comp/lz4.c
new file mode 100644
index 0000000..f9c753d
--- /dev/null
+++ b/lib/comp/lz4.c
@@ -0,0 +1,106 @@
+/* SPDX-License-Identifier: GPL-3.0-or-later */
+#include <stdbool.h>
+#include <stdlib.h>
+#include <string.h>
+#include <stdio.h>
+
+#include <lz4.h>
+#include <lz4hc.h>
+
+#include "internal.h"
+
+typedef struct {
+	compressor_t base;
+} lz4_compressor_t;
+
+typedef struct {
+	uint32_t version;
+	uint32_t flags;
+} lz4_options;
+
+#define LZ4LEGACY 1
+
+static int lz4_write_options(compressor_t *base, int fd)
+{
+	lz4_options opt = {
+		.version = htole32(LZ4LEGACY),
+		.flags = htole32(0),
+	};
+	(void)base;
+
+	return generic_write_options(fd, &opt, sizeof(opt));
+}
+
+static int lz4_read_options(compressor_t *base, int fd)
+{
+	lz4_options opt;
+	(void)base;
+
+	if (generic_read_options(fd, &opt, sizeof(opt)))
+		return -1;
+
+	opt.version = le32toh(opt.version);
+	opt.flags = le32toh(opt.flags);
+
+	if (opt.version != LZ4LEGACY) {
+		fprintf(stderr, "unsupported lz4 version '%d'\n", opt.version);
+		return -1;
+	}
+
+	return 0;
+}
+
+static ssize_t lz4_comp_block(compressor_t *base, const uint8_t *in,
+			      size_t size, uint8_t *out, size_t outsize)
+{
+	int ret;
+	(void)base;
+
+	ret = LZ4_compress_default((void *)in, (void *)out, size, outsize);
+
+	if (ret < 0) {
+		fputs("internal error in lz4 compressor\n", stderr);
+		return -1;
+	}
+
+	return ret;
+}
+
+static ssize_t lz4_uncomp_block(compressor_t *base, const uint8_t *in,
+				size_t size, uint8_t *out, size_t outsize)
+{
+	int ret;
+	(void)base;
+
+	ret = LZ4_decompress_safe((void *)in, (void *)out, size, outsize);
+
+	if (ret < 0) {
+		fputs("internal error in lz4 decompressor\n", stderr);
+		return -1;
+	}
+
+	return ret;
+}
+
+static void lz4_destroy(compressor_t *base)
+{
+	free(base);
+}
+
+compressor_t *create_lz4_compressor(bool compress, size_t block_size)
+{
+	lz4_compressor_t *lz4 = calloc(1, sizeof(*lz4));
+	compressor_t *base = (compressor_t *)lz4;
+	(void)block_size;
+
+	if (lz4 == NULL) {
+		perror("creating lz4 compressor");
+		return NULL;
+	}
+
+	base->destroy = lz4_destroy;
+	base->do_block = compress ? lz4_comp_block : lz4_uncomp_block;
+	base->write_options = lz4_write_options;
+	base->read_options = lz4_read_options;
+	return base;
+}
-- 
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