[linux-mm-cc] [RFC] LZO de/compression support in kernel [3/5]

[Nitin Gupta]

This contains stuff used internally by LZO code. This is not intended
to be used directly by other modules.

Signed-off-by: Nitin Gupta <nitingupta910 at gmail.com>


Index: linux-cc/lib/lzo1x/lzo1x_int.h
===================================================================
--- /dev/null
+++ linux-cc/lib/lzo1x/lzo1x_int.h
@@ -0,0 +1,105 @@
+/* lzo1x_int.h -- to be used internally by LZO de/compression algorithms
+
+   This file is part of the LZO real-time data compression library.
+
+   Copyright (C) 2005 Markus Franz Xaver Johannes Oberhumer
+   Copyright (C) 2004 Markus Franz Xaver Johannes Oberhumer
+   Copyright (C) 2003 Markus Franz Xaver Johannes Oberhumer
+   Copyright (C) 2002 Markus Franz Xaver Johannes Oberhumer
+   Copyright (C) 2001 Markus Franz Xaver Johannes Oberhumer
+   Copyright (C) 2000 Markus Franz Xaver Johannes Oberhumer
+   Copyright (C) 1999 Markus Franz Xaver Johannes Oberhumer
+   Copyright (C) 1998 Markus Franz Xaver Johannes Oberhumer
+   Copyright (C) 1997 Markus Franz Xaver Johannes Oberhumer
+   Copyright (C) 1996 Markus Franz Xaver Johannes Oberhumer
+   All Rights Reserved.
+
+   The LZO library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU General Public License,
+   version 2, as published by the Free Software Foundation.
+
+   The LZO library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with the LZO library; see the file COPYING.
+   If not, write to the Free Software Foundation, Inc.,
+   51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
+
+   Markus F.X.J. Oberhumer
+   <markus at oberhumer.com>
+   http://www.oberhumer.com/opensource/lzo/
+
+
+   This file was derived from several header files found in original
+   LZO 2.02 code. Some additional changes have also been made to make
+   it work in kernel space.
+
+   Nitin Gupta
+   <nitingupta910 at gmail.com>
+ */
+
+#ifndef __LZO1X_INT_H
+#define __LZO1X_INT_H
+
+#include <linux/types.h>
+
+#define D_SIZE		(1u << D_BITS)
+#define D_MASK		(D_SIZE - 1)
+#define D_HIGH		((D_MASK >> 1) + 1)
+
+#define DX2(p,s1,s2) \
+	(((((size_t)((p)[2]) << (s2)) ^ (p)[1]) << (s1)) ^ (p)[0])
+#define DX3(p,s1,s2,s3) ((DX2((p)+1,s2,s3) << (s1)) ^ (p)[0])
+#define DMUL(a,b)	((size_t) ((a) * (b)))
+#define DMS(v,s)	((size_t) (((v) & (D_MASK >> (s))) << (s)))
+#define DM(v)		DMS(v,0)
+
+#define D_BITS		14
+#define DINDEX1(d,p)	d = DM(DMUL(0x21,DX3(p,5,5,6)) >> 5)
+#define DINDEX2(d,p)	d = (d & (D_MASK & 0x7ff)) ^ (D_HIGH | 0x1f)
+#define DENTRY(p,in)	(p)
+
+#define PTR(a)		((unsigned long) (a))
+#define PTR_LT(a,b)	(PTR(a) < PTR(b))
+#define PTR_GE(a,b)	(PTR(a) >= PTR(b))
+#define PTR_DIFF(a,b)	(PTR(a) - PTR(b))
+#define pd(a,b)		((size_t) ((a)-(b)))
+
+#define LZO_CHECK_MPOS_NON_DET(m_pos,m_off,in,ip,max_offset) \
+	( m_pos = ip - (size_t) PTR_DIFF(ip,m_pos), \
+	PTR_LT(m_pos,in) || \
+	(m_off = (size_t) PTR_DIFF(ip,m_pos)) <= 0 || \
+	m_off > max_offset )
+
+#define COPY4(dst,src)	*(size_t *)(dst) = *(size_t *)(src)
+
+
+/* LZO1X Specific constants */
+
+#define M1_MAX_OFFSET	0x0400
+#define M2_MAX_OFFSET	0x0800
+#define M3_MAX_OFFSET	0x4000
+#define M4_MAX_OFFSET	0xbfff
+
+#define MX_MAX_OFFSET	(M1_MAX_OFFSET + M2_MAX_OFFSET)
+
+#define M1_MIN_LEN	2
+#define M1_MAX_LEN	2
+#define M2_MIN_LEN	3
+#define M2_MAX_LEN	8
+#define M3_MIN_LEN	3
+#define M3_MAX_LEN	33
+#define M4_MIN_LEN	3
+#define M4_MAX_LEN	9
+
+#define M1_MARKER	0
+#define M2_MARKER	64
+#define M3_MARKER	32
+#define M4_MARKER	16
+
+#define MIN_LOOKAHEAD	(M2_MAX_LEN + 1)
+
+#endif /* already included */