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authorRichard Purdie <rpurdie@openedhand.com>2007-07-10 16:03:31 +0100
committerJosh Boyer <jwboyer@gmail.com>2007-07-23 08:11:21 -0500
commit82f09a8b4e214e51c394ed9ff8882d1e736e205b (patch)
treed92d6b68d2576204c4a80136c362096816eca704 /compr_lzo.c
parenta6fa706fe9e7696b4b2045edf9698c3bac07e3e3 (diff)
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>
Diffstat (limited to 'compr_lzo.c')
-rw-r--r--compr_lzo.c120
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);
+}