/* lzo1a_cm.ch -- implementation of the LZO1A compression algorithm

   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.

 */

/***********************************************************************

// code the match in LZO1 compatible format

************************************************************************/

#define THRESHOLD   (M2_MIN_LEN - 1)

#define MSIZE       LZO_SIZE(M2L_BITS)

/***********************************************************************

//

************************************************************************/

#if (DD_BITS == 0)

        /* we already matched M2_MIN_LEN bytes,

         * m_pos also already advanced M2_MIN_LEN bytes */

        ip += M2_MIN_LEN;

        assert(m_pos < ip);

        /* try to match another M2_MAX_LEN + 1 - M2_MIN_LEN bytes

         * to see if we get more than a M2 match */

#define M2_OR_M3    (MATCH_M2)

#else /* (DD_BITS == 0) */

        /* we already matched m_len bytes */

        assert(m_len >= M2_MIN_LEN);

        ip += m_len;

        assert(ip <= in_end);

#define M2_OR_M3    (m_len <= M2_MAX_LEN)

#endif /* (DD_BITS == 0) */

        if (M2_OR_M3)

        {

        /* we've found a short match */

            assert(ip <= in_end);

        /* 2a) compute match parameters */

#if (DD_BITS == 0)

                assert(pd(ip,m_pos) == m_off);

            --ip;   /* ran one too far, point back to non-match */

            m_len = ip - ii;

#endif

                assert(m_len >= M2_MIN_LEN);

                assert(m_len <= M2_MAX_LEN);

                assert(m_off >= M2_MIN_OFFSET);

                assert(m_off <= M2_MAX_OFFSET);

                assert(ii-m_off == m_pos_sav);

                assert(lzo_memcmp(m_pos_sav,ii,m_len) == 0);

        /* 2b) code the match */

            m_off -= M2_MIN_OFFSET;

            /* code short match len + low offset bits */

            *op++ = LZO_BYTE(((m_len - THRESHOLD) << M2O_BITS) |

                             (m_off & M2O_MASK));

            /* code high offset bits */

            *op++ = LZO_BYTE(m_off >> M2O_BITS);

            if (ip >= ip_end)

            {

                ii = ip;

                break;

            }

        /* 2c) Insert phrases (beginning with ii+1) into the dictionary. */

#if (CLEVEL == 9) || (CLEVEL >= 7 && M2L_BITS <= 4) || (CLEVEL >= 5 && M2L_BITS <= 3)

        /* Insert the whole match (ii+1)..(ip-1) into dictionary.  */

            ++ii;

            do {

                DVAL_NEXT(dv,ii);

#if 0

                UPDATE_D(dict,drun,dv,ii,in);

#else

                dict[ DINDEX(dv,ii) ] = DENTRY(ii,in);

#endif

                MI

            } while (++ii < ip);

            DVAL_NEXT(dv,ii);

            assert(ii == ip);

            DVAL_ASSERT(dv,ip);

#elif (CLEVEL >= 3)

            SI   DI DI   XI

#elif (CLEVEL >= 2)

            SI   DI      XI

#else

                         XI

#endif

        }

        else

        {

        /* we've found a long match - see how far we can still go */

            const lzo_bytep end;

            assert(ip <= in_end);

            assert(ii == ip - (M2_MAX_LEN + 1));

            assert(lzo_memcmp(m_pos_sav,ii,(lzo_uint)(ip-ii)) == 0);

#if (DD_BITS > 0)

            assert(m_len == (lzo_uint)(ip-ii));

            m_pos = ip - m_off;

            assert(m_pos == m_pos_sav + m_len);

#endif

            if (pd(in_end,ip) <= (M3_MAX_LEN - M3_MIN_LEN))

                end = in_end;

            else

            {

                end = ip + (M3_MAX_LEN - M3_MIN_LEN);

                assert(end < in_end);

            }

            while (ip < end  &&  *m_pos == *ip)

                m_pos++, ip++;

            assert(ip <= in_end);

            /* 2a) compute match parameters */

            m_len = pd(ip, ii);

                assert(m_len >= M3_MIN_LEN);

                assert(m_len <= M3_MAX_LEN);

                assert(m_off >= M3_MIN_OFFSET);

                assert(m_off <= M3_MAX_OFFSET);

                assert(ii-m_off == m_pos_sav);

                assert(lzo_memcmp(m_pos_sav,ii,m_len) == 0);

                assert(pd(ip,m_pos) == m_off);

        /* 2b) code the match */

            m_off -= M3_MIN_OFFSET - M3_EOF_OFFSET;

            /* code long match flag + low offset bits */

            *op++ = LZO_BYTE(((MSIZE - 1) << M3O_BITS) | (m_off & M3O_MASK));

            /* code high offset bits */

            *op++ = LZO_BYTE(m_off >> M3O_BITS);

            /* code match len */

            *op++ = LZO_BYTE(m_len - M3_MIN_LEN);

            if (ip >= ip_end)

            {

                ii = ip;

                break;

            }

        /* 2c) Insert phrases (beginning with ii+1) into the dictionary. */

#if (CLEVEL == 9)

        /* Insert the whole match (ii+1)..(ip-1) into dictionary.  */

        /* This is not recommended because it can be slow. */

            ++ii;

            do {

                DVAL_NEXT(dv,ii);

#if 0

                UPDATE_D(dict,drun,dv,ii,in);

#else

                dict[ DINDEX(dv,ii) ] = DENTRY(ii,in);

#endif

                MI

            } while (++ii < ip);

            DVAL_NEXT(dv,ii);

            assert(ii == ip);

            DVAL_ASSERT(dv,ip);

#elif (CLEVEL >= 8)

            SI   DI DI DI DI DI DI DI DI   XI

#elif (CLEVEL >= 7)

            SI   DI DI DI DI DI DI DI      XI

#elif (CLEVEL >= 6)

            SI   DI DI DI DI DI DI         XI

#elif (CLEVEL >= 5)

            SI   DI DI DI DI               XI

#elif (CLEVEL >= 4)

            SI   DI DI DI                  XI

#elif (CLEVEL >= 3)

            SI   DI DI                     XI

#elif (CLEVEL >= 2)

            SI   DI                        XI

#else

                                           XI

#endif

        }

        /* ii now points to the start of the next literal run */

        assert(ii == ip);

/*

vi:ts=4:et

*/