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+/*
+ * 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_rtime.c,v 1.2 2002/01/24 22:58:42 rfeany Exp $
+ *
+ *
+ * Very simple lz77-ish encoder.
+ *
+ * Theory of operation: Both encoder and decoder have a list of "last
+ * occurances" for every possible source-value; after sending the
+ * first source-byte, the second byte indicated the "run" length of
+ * matches
+ *
+ * The algorithm is intended to only send "whole bytes", no bit-messing.
+ *
+ */
+
+#include <config.h>
+#if (CONFIG_COMMANDS & CFG_CMD_JFFS2)
+
+#include <jffs2/jffs2.h>
+
+void rtime_decompress(unsigned char *data_in, unsigned char *cpage_out,
+ u32 srclen, u32 destlen)
+{
+ int positions[256];
+ int outpos;
+ int pos;
+ int i;
+
+ outpos = pos = 0;
+
+ for (i = 0; i < 256; positions[i++] = 0);
+
+ while (outpos<destlen) {
+ unsigned char value;
+ int backoffs;
+ int repeat;
+
+ value = data_in[pos++];
+ cpage_out[outpos++] = value; /* first the verbatim copied byte */
+ repeat = data_in[pos++];
+ backoffs = positions[value];
+
+ positions[value]=outpos;
+ if (repeat) {
+ if (backoffs + repeat >= outpos) {
+ while(repeat) {
+ cpage_out[outpos++] = cpage_out[backoffs++];
+ repeat--;
+ }
+ } else {
+ for (i = 0; i < repeat; i++)
+ *(cpage_out + outpos + i) = *(cpage_out + backoffs + i);
+ outpos+=repeat;
+ }
+ }
+ }
+}
+
+#endif /* CFG_CMD_JFFS2 */
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