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+/* lzo1b_sm.ch -- implementation of the LZO1B compression algorithm
+
+ This file is part of the LZO real-time data compression library.
+
+ Copyright (C) 2011 Markus Franz Xaver Johannes Oberhumer
+ Copyright (C) 2010 Markus Franz Xaver Johannes Oberhumer
+ Copyright (C) 2009 Markus Franz Xaver Johannes Oberhumer
+ Copyright (C) 2008 Markus Franz Xaver Johannes Oberhumer
+ Copyright (C) 2007 Markus Franz Xaver Johannes Oberhumer
+ Copyright (C) 2006 Markus Franz Xaver Johannes Oberhumer
+ 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 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.
+ */
+
+
+
+/***********************************************************************
+// search for a match
+************************************************************************/
+
+#if (DD_BITS == 0)
+
+ /* search ip in the dictionary */
+ DINDEX1(dindex,ip);
+ GINDEX(m_pos,m_off,dict,dindex,in);
+ if (LZO_CHECK_MPOS_NON_DET(m_pos,m_off,in,ip,M3_MAX_OFFSET))
+ goto literal;
+#if 1
+ if (m_off <= M2_MAX_OFFSET || m_pos[3] == ip[3])
+ goto try_match;
+ DINDEX2(dindex,ip);
+#endif
+ GINDEX(m_pos,m_off,dict,dindex,in);
+ if (LZO_CHECK_MPOS_NON_DET(m_pos,m_off,in,ip,M3_MAX_OFFSET))
+ goto literal;
+ if (m_off <= M2_MAX_OFFSET || m_pos[3] == ip[3])
+ goto try_match;
+ goto literal;
+
+
+#else /* (DD_BITS == 0) */
+
+
+
+ /* search ip in the deepened dictionary */
+ {
+ lzo_dict_p d = &dict [ DINDEX(dv,ip) ];
+ const lzo_bytep ip_sav;
+ unsigned j = DD_SIZE;
+ lzo_uint x_len;
+ LZO_DEFINE_UNINITIALIZED_VAR(lzo_uint, x_off, 0);
+
+ DVAL_ASSERT(dv,ip);
+
+ ip_sav = ip;
+ m_len = 0;
+ do {
+#if !defined(NDEBUG)
+ const lzo_bytep z_pos = NULL;
+#endif
+#if (LZO_DICT_USE_PTR)
+ m_pos = *d;
+ assert((z_pos = m_pos) == *d);
+#if (LZO_DETERMINISTIC)
+ assert(m_pos == NULL || m_pos >= in);
+ assert(m_pos == NULL || m_pos < ip);
+#endif
+#else
+ x_off = *d;
+#endif
+ assert(ip == ip_sav);
+
+ if (LZO_CHECK_MPOS(m_pos,x_off,in,ip,MAX_OFFSET))
+#if (CLEVEL == 9)
+ *d = DENTRY(ip,in);
+#else
+ ((void)(0));
+#endif
+ else if (m_pos[m_len] != ip[m_len])
+ ((void)(0));
+ else if (*m_pos++ == *ip++ && *m_pos++ == *ip++ && *m_pos++ == *ip++)
+ {
+#if !(LZO_DICT_USE_PTR)
+ assert((z_pos = ip - 3 - x_off) == (m_pos - 3));
+#endif
+ /* a match */
+ if (MATCH_M2)
+ {
+ x_len = pd((ip - 1), ip_sav);
+ if (x_len > m_len)
+ {
+ m_len = x_len;
+ m_off = x_off;
+ assert((m_pos_sav = z_pos) != NULL);
+ }
+#if (CLEVEL == 9)
+ /* try to find a closer match */
+ else if (x_len == m_len && x_off < m_off)
+ {
+ m_off = x_off;
+ assert((m_pos_sav = z_pos) != NULL);
+ }
+#endif
+ }
+ else
+ {
+ assert((ip - ip_sav) == M2_MAX_LEN + 1);
+#if (CLEVEL == 9)
+#if defined(MATCH_IP_END)
+ {
+ const lzo_bytep end;
+ end = MATCH_IP_END;
+ while (ip < end && *m_pos == *ip)
+ m_pos++, ip++;
+ assert(ip <= in_end);
+ x_len = pd(ip, ip_sav);
+ }
+ if (x_len > m_len)
+ {
+ m_len = x_len;
+ m_off = x_off;
+ assert((m_pos_sav = z_pos) != NULL);
+ if (ip >= MATCH_IP_END)
+ {
+ ip = ip_sav;
+#if 0
+ /* not needed - we are at the end */
+ d -= DD_SIZE - j;
+ assert(d == &dict [ DINDEX(dv,ip) ]);
+ UPDATE_P(d,drun,ip,in);
+#endif
+ goto match;
+ }
+ }
+ else if (x_len == m_len && x_off < m_off)
+ {
+ m_off = x_off;
+ assert((m_pos_sav = z_pos) != NULL);
+ }
+#else
+ /* try to find a closer match */
+ if (m_len < M2_MAX_LEN + 1 || x_off < m_off)
+ {
+ m_len = M2_MAX_LEN + 1;
+ m_off = x_off;
+ assert((m_pos_sav = z_pos) != NULL);
+ }
+#endif
+#else
+ /* don't search for a longer/closer match */
+ m_len = M2_MAX_LEN + 1;
+ m_off = x_off;
+ assert((m_pos_sav = z_pos) != NULL);
+ ip = ip_sav;
+ d -= DD_SIZE - j;
+ assert(d == &dict [ DINDEX(dv,ip) ]);
+ UPDATE_P(d,drun,ip,in);
+ goto match;
+#endif
+ }
+ ip = ip_sav;
+ }
+ else
+ ip = ip_sav;
+ d++;
+ } while (--j > 0);
+ assert(ip == ip_sav);
+
+ d -= DD_SIZE;
+ assert(d == &dict [ DINDEX(dv,ip) ]);
+ UPDATE_P(d,drun,ip,in);
+ }
+
+#endif /* (DD_BITS == 0) */
+
+
+/*
+vi:ts=4:et
+*/