mirror of https://github.com/libAthena/athena.git
295 lines
7.2 KiB
Plaintext
295 lines
7.2 KiB
Plaintext
/* lzo1b_cm.ch -- implementation of the LZO1B compression algorithm
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This file is part of the LZO real-time data compression library.
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Copyright (C) 1996-2015 Markus Franz Xaver Johannes Oberhumer
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All Rights Reserved.
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The LZO library is free software; you can redistribute it and/or
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modify it under the terms of the GNU General Public License as
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published by the Free Software Foundation; either version 2 of
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the License, or (at your option) any later version.
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The LZO library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with the LZO library; see the file COPYING.
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If not, write to the Free Software Foundation, Inc.,
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51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
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Markus F.X.J. Oberhumer
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<markus@oberhumer.com>
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http://www.oberhumer.com/opensource/lzo/
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*/
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/* WARNING: this file should *not* be used by applications. It is
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part of the implementation of the library and is subject
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to change.
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*/
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/***********************************************************************
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// code the match
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************************************************************************/
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#if (DD_BITS == 0)
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/* we already matched M2_MIN_LEN bytes,
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* m_pos also already advanced M2_MIN_LEN bytes */
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ip += M2_MIN_LEN;
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assert(m_pos < ip);
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/* try to match another M2_MAX_LEN + 1 - M2_MIN_LEN bytes
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* to see if we get more than a M2 match */
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#define M2_OR_M3 (MATCH_M2)
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#else /* (DD_BITS == 0) */
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/* we already matched m_len bytes */
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assert(m_len >= M2_MIN_LEN);
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ip += m_len;
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assert(ip <= in_end);
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#define M2_OR_M3 (m_len <= M2_MAX_LEN)
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#endif /* (DD_BITS == 0) */
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if (M2_OR_M3)
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{
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/* we've found a M2 or M3 match */
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assert(ip <= in_end);
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/* 2a) compute match parameters */
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#if (DD_BITS == 0)
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assert(pd(ip, m_pos) == m_off);
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--ip; /* ran one too far, point back to non-match */
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m_len = pd(ip, ii);
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#endif
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/* 2a2) verify match parameters */
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assert(m_len >= M2_MIN_LEN);
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assert(m_len <= M2_MAX_LEN);
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assert(m_len <= M3_MAX_LEN);
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assert(m_off >= M2_MIN_OFFSET);
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assert(m_off >= M3_MIN_OFFSET);
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assert(m_off <= M3_MAX_OFFSET);
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assert(ii - m_off == m_pos_sav);
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assert(lzo_memcmp(m_pos_sav, ii, m_len) == 0);
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/* 2b) code the match */
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#if (_M2_MAX_OFFSET != _M3_MAX_OFFSET)
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if (m_off <= M2_MAX_OFFSET)
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{
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#else
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assert(m_off <= M2_MAX_OFFSET);
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#endif
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m_off -= M2_MIN_OFFSET;
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/* code match len + low offset bits */
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*op++ = LZO_BYTE(((m_len - (M2_MIN_LEN - 2)) << M2O_BITS) |
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(m_off & M2O_MASK));
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/* code high offset bits */
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*op++ = LZO_BYTE(m_off >> M2O_BITS);
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LZO_STATS(lzo_stats->m2_matches++);
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LZO_STATS(lzo_stats->m2_match[m_len]++);
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#if (_M2_MAX_OFFSET != _M3_MAX_OFFSET)
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}
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else
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{
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#if defined(LZO_HAVE_R1)
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#if (M3_MIN_LEN == M2_MIN_LEN)
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r1 = ip_end; /* invalidate R1 pointer */
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#endif
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#endif
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assert(m_len >= M3_MIN_LEN);
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m_off -= M3_MIN_OFFSET - M3_EOF_OFFSET;
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/* code match len */
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*op++ = LZO_BYTE(M3_MARKER | (m_len - (M3_MIN_LEN - 1)));
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/* code low offset bits */
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*op++ = LZO_BYTE(m_off & M3O_MASK);
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/* code high offset bits */
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*op++ = LZO_BYTE(m_off >> M3O_BITS);
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LZO_STATS(lzo_stats->m3_matches++);
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LZO_STATS(lzo_stats->m3_match[m_len]++);
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#if defined(LZO_HAVE_M3)
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m3 = op; /* set M3 pointer */
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#endif
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}
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#endif /* (_M2_MAX_OFFSET != _M3_MAX_OFFSET) */
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if (ip >= ip_end)
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{
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ii = ip;
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break;
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}
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/* 2c) Insert phrases (beginning with ii+1) into the dictionary. */
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#if (CLEVEL == 9) || (CLEVEL >= 7 && M2L_BITS <= 4) || (CLEVEL >= 5 && M2L_BITS <= 3)
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/* Insert the whole match (ii+1)..(ip-1) into dictionary. */
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++ii;
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do
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{
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DVAL_NEXT(dv, ii);
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#if 0
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UPDATE_D(dict, drun, dv, ii, in);
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#else
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dict[ DINDEX(dv, ii) ] = DENTRY(ii, in);
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#endif
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MI
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}
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while (++ii < ip);
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DVAL_NEXT(dv, ii);
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assert(ii == ip);
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DVAL_ASSERT(dv, ip);
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#elif (CLEVEL >= 3)
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SI DI DI XI
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#elif (CLEVEL >= 2)
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SI DI XI
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#else
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XI
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#endif
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}
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else
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{
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/* we've found a M3 or M4 match - see how far we can still go */
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assert(ip <= in_end);
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assert(lzo_memcmp(m_pos_sav, ii, (lzo_uint)(ip - ii)) == 0);
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/* 2a) compute match parameters */
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#if !defined(MATCH_IP_END)
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assert(ii == ip - (M2_MAX_LEN + 1));
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#if (DD_BITS > 0)
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assert(m_len == (lzo_uint)(ip - ii));
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m_pos = ip - m_off;
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assert(m_pos == m_pos_sav + m_len);
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#endif
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{
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const lzo_bytep end;
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end = in_end;
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while (ip < end && *m_pos == *ip)
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m_pos++, ip++;
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assert(ip <= in_end);
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m_len = pd(ip, ii);
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}
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assert(pd(ip, m_pos) == m_off);
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#endif
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/* 2a2) verify match parameters */
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assert(m_len >= M3_MIN_LEN);
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assert(m_off >= M3_MIN_OFFSET);
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assert(m_off >= M4_MIN_OFFSET);
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assert(m_off <= M3_MAX_OFFSET);
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assert(m_off <= M4_MAX_OFFSET);
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assert(ii - m_off == m_pos_sav);
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assert(lzo_memcmp(m_pos_sav, ii, m_len) == 0);
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/* 2b) code the match */
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if (m_len <= M3_MAX_LEN)
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{
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/* code match len */
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*op++ = LZO_BYTE(M3_MARKER | (m_len - (M3_MIN_LEN - 1)));
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LZO_STATS(lzo_stats->m3_matches++);
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LZO_STATS(lzo_stats->m3_match[m_len]++);
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}
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else
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{
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assert(m_len >= M4_MIN_LEN);
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/* code M4 match len flag */
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*op++ = M4_MARKER;
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/* code match len */
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m_len -= M4_MIN_LEN - 1;
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while (m_len > 255)
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{
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m_len -= 255;
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*op++ = 0;
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}
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assert(m_len > 0);
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*op++ = LZO_BYTE(m_len);
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LZO_STATS(lzo_stats->m4_matches++);
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}
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m_off -= M3_MIN_OFFSET - M3_EOF_OFFSET;
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/* code low offset bits */
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*op++ = LZO_BYTE(m_off & M3O_MASK);
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/* code high offset bits */
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*op++ = LZO_BYTE(m_off >> M3O_BITS);
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#if defined(LZO_HAVE_M3)
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m3 = op; /* set M3 pointer */
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#endif
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if (ip >= ip_end)
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{
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ii = ip;
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break;
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}
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/* 2c) Insert phrases (beginning with ii+1) into the dictionary. */
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#if (CLEVEL == 9)
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/* Insert the whole match (ii+1)..(ip-1) into dictionary. */
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/* This is not recommended because it can be slow. */
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++ii;
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do
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{
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DVAL_NEXT(dv, ii);
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#if 0
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UPDATE_D(dict, drun, dv, ii, in);
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#else
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dict[ DINDEX(dv, ii) ] = DENTRY(ii, in);
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#endif
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MI
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}
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while (++ii < ip);
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DVAL_NEXT(dv, ii);
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assert(ii == ip);
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DVAL_ASSERT(dv, ip);
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#elif (CLEVEL >= 8)
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SI DI DI DI DI DI DI DI DI XI
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#elif (CLEVEL >= 7)
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SI DI DI DI DI DI DI DI XI
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#elif (CLEVEL >= 6)
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SI DI DI DI DI DI DI XI
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#elif (CLEVEL >= 5)
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SI DI DI DI DI XI
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#elif (CLEVEL >= 4)
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SI DI DI DI XI
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#elif (CLEVEL >= 3)
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SI DI DI XI
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#elif (CLEVEL >= 2)
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SI DI XI
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#else
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XI
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#endif
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}
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/* ii now points to the start of the next literal run */
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assert(ii == ip);
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/* vim:set ts=4 sw=4 et: */
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