Add lzo support to mtd-utils

Add LZO support to mtd-utils to generate LZO compressed jffs2 images

Unlike the kernel version, the standard lzo userspace library is used
along with lzo1x_999_compress rather than the lzo1x_1_compress version
since better compression ratios can be obtained (at no significant cost
to decompression time).

Signed-off-by: Richard Purdie <rpurdie@openedhand.com>
Signed-off-by: Josh Boyer <jwboyer@gmail.com>

1 files changed, 120 insertions, 0 deletions

diff --git a/compr_lzo.c b/compr_lzo.c
new file mode 100644
index 0000000..ef3b413
--- /dev/null
+++ b/compr_lzo.c
@@ -0,0 +1,120 @@
+/*
+ * JFFS2 LZO Compression Interface.
+ *
+ * Copyright (C) 2007 Nokia Corporation. All rights reserved.
+ *
+ * Author: Richard Purdie <rpurdie@openedhand.com>
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * version 2 as published by the Free Software Foundation.
+ *
+ * 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, Inc., 51 Franklin St, Fifth Floor, Boston, MA
+ * 02110-1301 USA
+ *
+ */
+
+#include <stdint.h>
+#include <stdio.h>
+#include <string.h>
+#include <asm/types.h>
+#include <linux/jffs2.h>
+#include <lzo1x.h>
+#include "compr.h"
+
+extern int page_size;
+
+static void *lzo_mem;
+static void *lzo_compress_buf;
+
+/*
+ * Note about LZO compression.
+ *
+ * We want to use the _999_ compression routine which gives better compression
+ * rates at the expense of time. Decompression time is unaffected. We might as
+ * well use the standard lzo library routines for this but they will overflow
+ * the destination buffer since they don't check the destination size.
+ *
+ * We therefore compress to a temporary buffer and copy if it will fit.
+ *
+ */
+static int jffs2_lzo_cmpr(unsigned char *data_in, unsigned char *cpage_out,
+			  uint32_t *sourcelen, uint32_t *dstlen, void *model)
+{
+	uint32_t compress_size;
+	int ret;
+
+	ret = lzo1x_999_compress(data_in, *sourcelen, lzo_compress_buf, &compress_size, lzo_mem);
+
+	if (ret != LZO_E_OK)
+		return -1;
+
+	if (compress_size > *dstlen)
+		return -1;
+
+	memcpy(cpage_out, lzo_compress_buf, compress_size);
+	*dstlen = compress_size;
+
+	return 0;
+}
+
+static int jffs2_lzo_decompress(unsigned char *data_in, unsigned char *cpage_out,
+				 uint32_t srclen, uint32_t destlen, void *model)
+{
+	int ret;
+	uint32_t dl;
+
+	ret = lzo1x_decompress_safe(data_in,srclen,cpage_out,&dl,NULL);
+
+	if (ret != LZO_E_OK || dl != destlen)
+		return -1;
+
+	return 0;
+}
+
+static struct jffs2_compressor jffs2_lzo_comp = {
+	.priority = JFFS2_LZO_PRIORITY,
+	.name = "lzo",
+	.compr = JFFS2_COMPR_LZO,
+	.compress = &jffs2_lzo_cmpr,
+	.decompress = &jffs2_lzo_decompress,
+	.disabled = 0,
+};
+
+int jffs2_lzo_init(void)
+{
+	int ret;
+
+	lzo_mem = malloc(LZO1X_999_MEM_COMPRESS);
+	if (!lzo_mem)
+		return -1;
+
+	/* Worse case LZO compression size from their FAQ */
+	lzo_compress_buf = malloc(page_size + (page_size / 64) + 16 + 3);
+	if (!lzo_compress_buf) {
+		free(lzo_mem);
+		return -1;
+	}
+
+	ret = jffs2_register_compressor(&jffs2_lzo_comp);
+	if (ret < 0) {
+		free(lzo_compress_buf);
+		free(lzo_mem);
+	}
+
+	return ret;
+}
+
+void jffs2_lzo_exit(void)
+{
+	jffs2_unregister_compressor(&jffs2_lzo_comp);
+	free(lzo_compress_buf);
+	free(lzo_mem);
+}