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author | wdenk <wdenk> | 2002-11-03 00:38:21 +0000 |
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committer | wdenk <wdenk> | 2002-11-03 00:38:21 +0000 |
commit | fe8c2806cdba70479e351299881a395dc2be7785 (patch) | |
tree | a1e8b98a1838cba6e6f5c765d9d85339257c45f5 /fs/jffs2/compr_rtime.c | |
parent | f9087a3213cc245cf9b90436475b5af822bd7579 (diff) | |
download | u-boot-imx-fe8c2806cdba70479e351299881a395dc2be7785.zip u-boot-imx-fe8c2806cdba70479e351299881a395dc2be7785.tar.gz u-boot-imx-fe8c2806cdba70479e351299881a395dc2be7785.tar.bz2 |
Initial revision
Diffstat (limited to 'fs/jffs2/compr_rtime.c')
-rw-r--r-- | fs/jffs2/compr_rtime.c | 91 |
1 files changed, 91 insertions, 0 deletions
diff --git a/fs/jffs2/compr_rtime.c b/fs/jffs2/compr_rtime.c new file mode 100644 index 0000000..9bb4f1b --- /dev/null +++ b/fs/jffs2/compr_rtime.c @@ -0,0 +1,91 @@ +/* + * 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 */ |