source: bootcd/isolinux/syslinux-6.03/lzo/src/lzo_dict.h

/* lzo_dict.h -- dictionary definitions for the the LZO library

   This file is part of the LZO real-time data compression library.

   Copyright (C) 1996-2014 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 as
   published by the Free Software Foundation; either version 2 of
   the License, or (at your option) any later version.

   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@oberhumer.com>
   http://www.oberhumer.com/opensource/lzo/
 */


/* WARNING: this file should *not* be used by applications. It is
   part of the implementation of the library and is subject
   to change.
 */


#ifndef __LZO_DICT_H
#define __LZO_DICT_H 1

#ifdef __cplusplus
extern "C" {
#endif



/***********************************************************************
// dictionary size
************************************************************************/

/* dictionary needed for compression */
#if !defined(D_BITS) && defined(DBITS)
#  define D_BITS        DBITS
#endif
#if !defined(D_BITS)
#  error "D_BITS is not defined"
#endif
#if (D_BITS < 16)
#  define D_SIZE        LZO_SIZE(D_BITS)
#  define D_MASK        LZO_MASK(D_BITS)
#else
#  define D_SIZE        LZO_USIZE(D_BITS)
#  define D_MASK        LZO_UMASK(D_BITS)
#endif
#define D_HIGH          ((D_MASK >> 1) + 1)


/* dictionary depth */
#if !defined(DD_BITS)
#  define DD_BITS       0
#endif
#define DD_SIZE         LZO_SIZE(DD_BITS)
#define DD_MASK         LZO_MASK(DD_BITS)

/* dictionary length */
#if !defined(DL_BITS)
#  define DL_BITS       (D_BITS - DD_BITS)
#endif
#if (DL_BITS < 16)
#  define DL_SIZE       LZO_SIZE(DL_BITS)
#  define DL_MASK       LZO_MASK(DL_BITS)
#else
#  define DL_SIZE       LZO_USIZE(DL_BITS)
#  define DL_MASK       LZO_UMASK(DL_BITS)
#endif


#if (D_BITS != DL_BITS + DD_BITS)
#  error "D_BITS does not match"
#endif
#if (D_BITS < 6 || D_BITS > 18)
#  error "invalid D_BITS"
#endif
#if (DL_BITS < 6 || DL_BITS > 20)
#  error "invalid DL_BITS"
#endif
#if (DD_BITS < 0 || DD_BITS > 6)
#  error "invalid DD_BITS"
#endif


#if !defined(DL_MIN_LEN)
#  define DL_MIN_LEN    3
#endif
#if !defined(DL_SHIFT)
#  define DL_SHIFT      ((DL_BITS + (DL_MIN_LEN - 1)) / DL_MIN_LEN)
#endif



/***********************************************************************
// dictionary access
************************************************************************/

#define LZO_HASH_GZIP                   1
#define LZO_HASH_GZIP_INCREMENTAL       2
#define LZO_HASH_LZO_INCREMENTAL_A      3
#define LZO_HASH_LZO_INCREMENTAL_B      4

#if !defined(LZO_HASH)
#  error "choose a hashing strategy"
#endif

#undef DM
#undef DX

#if (DL_MIN_LEN == 3)
#  define _DV2_A(p,shift1,shift2) \
        (((( (lzo_xint)((p)[0]) << shift1) ^ (p)[1]) << shift2) ^ (p)[2])
#  define _DV2_B(p,shift1,shift2) \
        (((( (lzo_xint)((p)[2]) << shift1) ^ (p)[1]) << shift2) ^ (p)[0])
#  define _DV3_B(p,shift1,shift2,shift3) \
        ((_DV2_B((p)+1,shift1,shift2) << (shift3)) ^ (p)[0])
#elif (DL_MIN_LEN == 2)
#  define _DV2_A(p,shift1,shift2) \
        (( (lzo_xint)(p[0]) << shift1) ^ p[1])
#  define _DV2_B(p,shift1,shift2) \
        (( (lzo_xint)(p[1]) << shift1) ^ p[2])
#else
#  error "invalid DL_MIN_LEN"
#endif
#define _DV_A(p,shift)      _DV2_A(p,shift,shift)
#define _DV_B(p,shift)      _DV2_B(p,shift,shift)
#define DA2(p,s1,s2) \
        (((((lzo_xint)((p)[2]) << (s2)) + (p)[1]) << (s1)) + (p)[0])
#define DS2(p,s1,s2) \
        (((((lzo_xint)((p)[2]) << (s2)) - (p)[1]) << (s1)) - (p)[0])
#define DX2(p,s1,s2) \
        (((((lzo_xint)((p)[2]) << (s2)) ^ (p)[1]) << (s1)) ^ (p)[0])
#define DA3(p,s1,s2,s3) ((DA2((p)+1,s2,s3) << (s1)) + (p)[0])
#define DS3(p,s1,s2,s3) ((DS2((p)+1,s2,s3) << (s1)) - (p)[0])
#define DX3(p,s1,s2,s3) ((DX2((p)+1,s2,s3) << (s1)) ^ (p)[0])
#define DMS(v,s)        ((lzo_uint) (((v) & (D_MASK >> (s))) << (s)))
#define DM(v)           DMS(v,0)


#if (LZO_HASH == LZO_HASH_GZIP)
   /* hash function like in gzip/zlib (deflate) */
#  define _DINDEX(dv,p)     (_DV_A((p),DL_SHIFT))

#elif (LZO_HASH == LZO_HASH_GZIP_INCREMENTAL)
   /* incremental hash like in gzip/zlib (deflate) */
#  define __LZO_HASH_INCREMENTAL 1
#  define DVAL_FIRST(dv,p)  dv = _DV_A((p),DL_SHIFT)
#  define DVAL_NEXT(dv,p)   dv = (((dv) << DL_SHIFT) ^ p[2])
#  define _DINDEX(dv,p)     (dv)
#  define DVAL_LOOKAHEAD    DL_MIN_LEN

#elif (LZO_HASH == LZO_HASH_LZO_INCREMENTAL_A)
   /* incremental LZO hash version A */
#  define __LZO_HASH_INCREMENTAL 1
#  define DVAL_FIRST(dv,p)  dv = _DV_A((p),5)
#  define DVAL_NEXT(dv,p) \
                dv ^= (lzo_xint)(p[-1]) << (2*5); dv = (((dv) << 5) ^ p[2])
#  define _DINDEX(dv,p)     ((DMUL(0x9f5f,dv)) >> 5)
#  define DVAL_LOOKAHEAD    DL_MIN_LEN

#elif (LZO_HASH == LZO_HASH_LZO_INCREMENTAL_B)
   /* incremental LZO hash version B */
#  define __LZO_HASH_INCREMENTAL 1
#  define DVAL_FIRST(dv,p)  dv = _DV_B((p),5)
#  define DVAL_NEXT(dv,p) \
                dv ^= p[-1]; dv = (((dv) >> 5) ^ ((lzo_xint)(p[2]) << (2*5)))
#  define _DINDEX(dv,p)     ((DMUL(0x9f5f,dv)) >> 5)
#  define DVAL_LOOKAHEAD    DL_MIN_LEN

#else
#  error "choose a hashing strategy"
#endif


#ifndef DINDEX
#define DINDEX(dv,p)        ((lzo_uint)((_DINDEX(dv,p)) & DL_MASK) << DD_BITS)
#endif
#if !defined(DINDEX1) && defined(D_INDEX1)
#define DINDEX1             D_INDEX1
#endif
#if !defined(DINDEX2) && defined(D_INDEX2)
#define DINDEX2             D_INDEX2
#endif



#if !defined(__LZO_HASH_INCREMENTAL)
#  define DVAL_FIRST(dv,p)  ((void) 0)
#  define DVAL_NEXT(dv,p)   ((void) 0)
#  define DVAL_LOOKAHEAD    0
#endif


#if !defined(DVAL_ASSERT)
#if defined(__LZO_HASH_INCREMENTAL) && !defined(NDEBUG)
#if (LZO_CC_CLANG || (LZO_CC_GNUC >= 0x020700ul) || LZO_CC_LLVM)
static void __attribute__((__unused__))
#else
static void
#endif
DVAL_ASSERT(lzo_xint dv, const lzo_bytep p)
{
    lzo_xint df;
    DVAL_FIRST(df,(p));
    assert(DINDEX(dv,p) == DINDEX(df,p));
}
#else
#  define DVAL_ASSERT(dv,p) ((void) 0)
#endif
#endif



/***********************************************************************
// dictionary updating
************************************************************************/

#if (LZO_DICT_USE_PTR)
#  define DENTRY(p,in)                          (p)
#  define GINDEX(m_pos,m_off,dict,dindex,in)    m_pos = dict[dindex]
#else
#  define DENTRY(p,in)                          ((lzo_dict_t) pd(p, in))
#  define GINDEX(m_pos,m_off,dict,dindex,in)    m_off = dict[dindex]
#endif


#if (DD_BITS == 0)

#  define UPDATE_D(dict,drun,dv,p,in)       dict[ DINDEX(dv,p) ] = DENTRY(p,in)
#  define UPDATE_I(dict,drun,index,p,in)    dict[index] = DENTRY(p,in)
#  define UPDATE_P(ptr,drun,p,in)           (ptr)[0] = DENTRY(p,in)

#else

#  define UPDATE_D(dict,drun,dv,p,in)   \
        dict[ DINDEX(dv,p) + drun++ ] = DENTRY(p,in); drun &= DD_MASK
#  define UPDATE_I(dict,drun,index,p,in)    \
        dict[ (index) + drun++ ] = DENTRY(p,in); drun &= DD_MASK
#  define UPDATE_P(ptr,drun,p,in)   \
        (ptr) [ drun++ ] = DENTRY(p,in); drun &= DD_MASK

#endif


/***********************************************************************
// test for a match
************************************************************************/

#if (LZO_DICT_USE_PTR)

/* m_pos is either NULL or a valid pointer */
#define LZO_CHECK_MPOS_DET(m_pos,m_off,in,ip,max_offset) \
        (m_pos == NULL || (m_off = pd(ip, m_pos)) > max_offset)

/* m_pos may point anywhere... */
#define LZO_CHECK_MPOS_NON_DET(m_pos,m_off,in,ip,max_offset) \
    (BOUNDS_CHECKING_OFF_IN_EXPR(( \
        m_pos = ip - (lzo_uint) PTR_DIFF(ip,m_pos), \
        PTR_LT(m_pos,in) || \
        (m_off = (lzo_uint) PTR_DIFF(ip,m_pos)) == 0 || \
         m_off > max_offset )))

#else

#define LZO_CHECK_MPOS_DET(m_pos,m_off,in,ip,max_offset) \
        (m_off == 0 || \
         ((m_off = pd(ip, in) - m_off) > max_offset) || \
         (m_pos = (ip) - (m_off), 0) )

#define LZO_CHECK_MPOS_NON_DET(m_pos,m_off,in,ip,max_offset) \
        (pd(ip, in) <= m_off || \
         ((m_off = pd(ip, in) - m_off) > max_offset) || \
         (m_pos = (ip) - (m_off), 0) )

#endif


#if (LZO_DETERMINISTIC)
#  define LZO_CHECK_MPOS    LZO_CHECK_MPOS_DET
#else
#  define LZO_CHECK_MPOS    LZO_CHECK_MPOS_NON_DET
#endif



#ifdef __cplusplus
} /* extern "C" */
#endif

#endif /* already included */

/*
vi:ts=4:et
*/