Initial revision

1 files changed, 124 insertions, 0 deletions

diff --git a/fs/jffs2/compr_rubin.c b/fs/jffs2/compr_rubin.c
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+++ b/fs/jffs2/compr_rubin.c
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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>
+ *
+ * Heavily modified by Russ Dill <Russ.Dill@asu.edu> in an attempt at
+ * a little more speed.
+ *
+ * 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_rubin.c,v 1.2 2002/01/24 22:58:42 rfeany Exp $
+ *
+ */
+
+#include <config.h>
+#if (CONFIG_COMMANDS & CFG_CMD_JFFS2)
+
+#include <jffs2/jffs2.h>
+#include <jffs2/compr_rubin.h>
+
+
+void rubin_do_decompress(unsigned char *bits, unsigned char *in,
+			 unsigned char *page_out, __u32 destlen)
+{
+	register char *curr = page_out;
+	char *end = page_out + destlen;
+	register unsigned long temp;
+	register unsigned long result;
+	register unsigned long p;
+	register unsigned long q;
+	register unsigned long rec_q;
+	register unsigned long bit;
+	register long i0;
+	unsigned long i;
+
+	/* init_pushpull */
+	temp = *(u32 *) in;
+	bit = 16;
+
+	/* init_rubin */
+	q = 0;
+	p = (long) (2 * UPPER_BIT_RUBIN);
+
+	/* init_decode */
+	rec_q = (in[0] << 8) | in[1];
+
+	while (curr < end) {
+		/* in byte */
+
+		result = 0;
+		for (i = 0; i < 8; i++) {
+			/* decode */
+
+			while ((q & UPPER_BIT_RUBIN) || ((p + q) <= UPPER_BIT_RUBIN)) {
+				q &= ~UPPER_BIT_RUBIN;
+				q <<= 1;
+				p <<= 1;
+				rec_q &= ~UPPER_BIT_RUBIN;
+				rec_q <<= 1;
+				rec_q |= (temp >> (bit++ ^ 7)) & 1;
+				if (bit > 31) {
+					bit = 0;
+					temp = *(++((u32 *) in));
+				}
+			}
+			i0 =  (bits[i] * p) >> 8;
+
+			if (i0 <= 0) i0 = 1;
+			/* if it fails, it fails, we have our crc
+			if (i0 >= p) i0 = p - 1; */
+
+			result >>= 1;
+			if (rec_q < q + i0) {
+				/* result |= 0x00; */
+				p = i0;
+			} else {
+				result |= 0x80;
+				p -= i0;
+				q += i0;
+			}
+		}
+		*(curr++) = result;
+	}
+}
+
+void dynrubin_decompress(unsigned char *data_in, unsigned char *cpage_out,
+		   unsigned long sourcelen, unsigned long dstlen)
+{
+	unsigned char bits[8];
+	int c;
+
+	for (c=0; c<8; c++)
+		bits[c] = (256 - data_in[c]);
+
+	rubin_do_decompress(bits, data_in+8, cpage_out, dstlen);
+}
+
+#endif /* CFG_CMD_JFFS2 */