/* * 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> #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 = (char *)page_out; char *end = (char *)(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) { u32 *p = (u32 *)in; bit = 0; temp = *(++p); in = (unsigned char *)p; } } 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); }