patch-2.4.10 linux/fs/jffs2/compr.c

• Lines: 144
• Date: Fri Sep 14 14:04:07 2001
• Orig file: v2.4.9/linux/fs/jffs2/compr.c
• Orig date: Wed Dec 31 16:00:00 1969

diff -u --recursive --new-file v2.4.9/linux/fs/jffs2/compr.c linux/fs/jffs2/compr.c
@@ -0,0 +1,143 @@
+/*
+ * JFFS2 -- Journalling Flash File System, Version 2.
+ *
+ * Copyright (C) 2001 Red Hat, Inc.
+ *
+ * Created by Arjan van de Ven <arjanv@redhat.com>
+ *
+ * The original JFFS, from which the design for JFFS2 was derived,
+ * was designed and implemented by Axis Communications AB.
+ *
+ * The contents of this file are subject to the Red Hat eCos Public
+ * License Version 1.1 (the "Licence"); you may not use this file
+ * except in compliance with the Licence.  You may obtain a copy of
+ * the Licence at http://www.redhat.com/
+ *
+ * Software distributed under the Licence is distributed on an "AS IS"
+ * basis, WITHOUT WARRANTY OF ANY KIND, either express or implied.
+ * See the Licence for the specific language governing rights and
+ * limitations under the Licence.
+ *
+ * The Original Code is JFFS2 - Journalling Flash File System, version 2
+ *
+ * Alternatively, the contents of this file may be used under the
+ * terms of the GNU General Public License version 2 (the "GPL"), in
+ * which case the provisions of the GPL are applicable instead of the
+ * above.  If you wish to allow the use of your version of this file
+ * only under the terms of the GPL and not to allow others to use your
+ * version of this file under the RHEPL, indicate your decision by
+ * deleting the provisions above and replace them with the notice and
+ * other provisions required by the GPL.  If you do not delete the
+ * provisions above, a recipient may use your version of this file
+ * under either the RHEPL or the GPL.
+ *
+ * $Id: compr.c,v 1.16 2001/03/15 15:38:23 dwmw2 Exp $
+ *
+ */
+
+#include <linux/kernel.h>
+#include <linux/string.h>
+#include <linux/types.h>
+#include <linux/errno.h>
+#include <linux/jffs2.h>
+
+int zlib_compress(unsigned char *data_in, unsigned char *cpage_out, __u32 *sourcelen, __u32 *dstlen);
+void zlib_decompress(unsigned char *data_in, unsigned char *cpage_out, __u32 srclen, __u32 destlen);
+int rtime_compress(unsigned char *data_in, unsigned char *cpage_out, __u32 *sourcelen, __u32 *dstlen);
+void rtime_decompress(unsigned char *data_in, unsigned char *cpage_out, __u32 srclen, __u32 destlen);
+int rubinmips_compress(unsigned char *data_in, unsigned char *cpage_out, __u32 *sourcelen, __u32 *dstlen);
+void rubinmips_decompress(unsigned char *data_in, unsigned char *cpage_out, __u32 srclen, __u32 destlen);
+int dynrubin_compress(unsigned char *data_in, unsigned char *cpage_out, __u32 *sourcelen, __u32 *dstlen);
+void dynrubin_decompress(unsigned char *data_in, unsigned char *cpage_out, __u32 srclen, __u32 destlen);
+
+
+/* jffs2_compress:
+ * @data: Pointer to uncompressed data
+ * @cdata: Pointer to buffer for compressed data
+ * @datalen: On entry, holds the amount of data available for compression.
+ *	On exit, expected to hold the amount of data actually compressed.
+ * @cdatalen: On entry, holds the amount of space available for compressed
+ *	data. On exit, expected to hold the actual size of the compressed
+ *	data.
+ *
+ * Returns: Byte to be stored with data indicating compression type used.
+ * Zero is used to show that the data could not be compressed - the 
+ * compressed version was actually larger than the original.
+ *
+ * If the cdata buffer isn't large enough to hold all the uncompressed data,
+ * jffs2_compress should compress as much as will fit, and should set 
+ * *datalen accordingly to show the amount of data which were compressed.
+ */
+unsigned char jffs2_compress(unsigned char *data_in, unsigned char *cpage_out, 
+		    __u32 *datalen, __u32 *cdatalen)
+{
+	int ret;
+
+	ret = zlib_compress(data_in, cpage_out, datalen, cdatalen);
+	if (!ret) {
+		return JFFS2_COMPR_ZLIB;
+	}
+
+	ret = dynrubin_compress(data_in, cpage_out, datalen, cdatalen);
+	if (!ret) {
+		return JFFS2_COMPR_DYNRUBIN;
+	}
+
+#if 0 /* Phase this one out */
+	ret = rubinmips_compress(data_in, cpage_out, datalen, cdatalen);
+	if (!ret) {
+		return JFFS2_COMPR_RUBINMIPS;
+	}
+#endif
+	ret = rtime_compress(data_in, cpage_out, datalen, cdatalen);
+	if (!ret) {
+		return JFFS2_COMPR_RTIME;
+	}
+#if 0
+	/* We don't need to copy. Let the caller special-case the COMPR_NONE case. */
+	/* If we get here, no compression is going to work */
+	/* But we might want to use the fragmentation part -- Arjan */
+	memcpy(cpage_out,data_in,min(*datalen,*cdatalen));
+	if (*datalen > *cdatalen)
+		*datalen = *cdatalen;
+#endif		
+	return JFFS2_COMPR_NONE; /* We failed to compress */
+
+}
+
+
+int jffs2_decompress(unsigned char comprtype, unsigned char *cdata_in, 
+		     unsigned char *data_out, __u32 cdatalen, __u32 datalen)
+{
+	switch (comprtype) {
+	case JFFS2_COMPR_NONE:
+		/* This should be special-cased elsewhere, but we might as well deal with it */
+		memcpy(data_out, cdata_in, datalen);
+		break;
+
+	case JFFS2_COMPR_ZERO:
+		memset(data_out, 0, datalen);
+		break;
+
+	case JFFS2_COMPR_ZLIB:
+		zlib_decompress(cdata_in, data_out, cdatalen, datalen);
+		break;
+
+	case JFFS2_COMPR_RTIME:
+		rtime_decompress(cdata_in, data_out, cdatalen, datalen);
+		break;
+#if 1 /* Phase this one out */
+	case JFFS2_COMPR_RUBINMIPS:
+		rubinmips_decompress(cdata_in, data_out, cdatalen, datalen);
+		break;
+#endif
+	case JFFS2_COMPR_DYNRUBIN:
+		dynrubin_decompress(cdata_in, data_out, cdatalen, datalen);
+		break;
+
+	default:
+		printk(KERN_NOTICE "Unknown JFFS2 compression type 0x%02x\n", comprtype);
+		return -EIO;
+	}
+	return 0;
+}