/* lzo1b_cm.ch -- implementation of the LZO1B 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 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 ************************************************************************/ #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 M2 or M3 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 = pd(ip, ii); #endif /* 2a2) verify match parameters */ assert(m_len >= M2_MIN_LEN); assert(m_len <= M2_MAX_LEN); assert(m_len <= M3_MAX_LEN); assert(m_off >= M2_MIN_OFFSET); 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); /* 2b) code the match */ #if (_M2_MAX_OFFSET != _M3_MAX_OFFSET) if (m_off <= M2_MAX_OFFSET) { #else assert(m_off <= M2_MAX_OFFSET); #endif m_off -= M2_MIN_OFFSET; /* code match len + low offset bits */ *op++ = LZO_BYTE(((m_len - (M2_MIN_LEN - 2)) << M2O_BITS) | (m_off & M2O_MASK)); /* code high offset bits */ *op++ = LZO_BYTE(m_off >> M2O_BITS); LZO_STATS(lzo_stats->m2_matches++); LZO_STATS(lzo_stats->m2_match[m_len]++); #if (_M2_MAX_OFFSET != _M3_MAX_OFFSET) } else { #if defined(LZO_HAVE_R1) #if (M3_MIN_LEN == M2_MIN_LEN) r1 = ip_end; /* invalidate R1 pointer */ #endif #endif assert(m_len >= M3_MIN_LEN); m_off -= M3_MIN_OFFSET - M3_EOF_OFFSET; /* code match len */ *op++ = LZO_BYTE(M3_MARKER | (m_len - (M3_MIN_LEN - 1))); /* code low offset bits */ *op++ = LZO_BYTE(m_off & M3O_MASK); /* code high offset bits */ *op++ = LZO_BYTE(m_off >> M3O_BITS); LZO_STATS(lzo_stats->m3_matches++); LZO_STATS(lzo_stats->m3_match[m_len]++); #if defined(LZO_HAVE_M3) m3 = op; /* set M3 pointer */ #endif } #endif /* (_M2_MAX_OFFSET != _M3_MAX_OFFSET) */ 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 M3 or M4 match - see how far we can still go */ assert(ip <= in_end); assert(lzo_memcmp(m_pos_sav,ii,(lzo_uint)(ip-ii)) == 0); /* 2a) compute match parameters */ #if !defined(MATCH_IP_END) assert(ii == ip - (M2_MAX_LEN + 1)); #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 { const lzo_bytep end; end = in_end; while (ip < end && *m_pos == *ip) m_pos++, ip++; assert(ip <= in_end); m_len = pd(ip, ii); } assert(pd(ip,m_pos) == m_off); #endif /* 2a2) verify match parameters */ assert(m_len >= M3_MIN_LEN); assert(m_off >= M3_MIN_OFFSET); assert(m_off >= M4_MIN_OFFSET); assert(m_off <= M3_MAX_OFFSET); assert(m_off <= M4_MAX_OFFSET); assert(ii-m_off == m_pos_sav); assert(lzo_memcmp(m_pos_sav,ii,m_len) == 0); /* 2b) code the match */ if (m_len <= M3_MAX_LEN) { /* code match len */ *op++ = LZO_BYTE(M3_MARKER | (m_len - (M3_MIN_LEN - 1))); LZO_STATS(lzo_stats->m3_matches++); LZO_STATS(lzo_stats->m3_match[m_len]++); } else { assert(m_len >= M4_MIN_LEN); /* code M4 match len flag */ *op++ = M4_MARKER; /* code match len */ m_len -= M4_MIN_LEN - 1; while (m_len > 255) { m_len -= 255; *op++ = 0; } assert(m_len > 0); *op++ = LZO_BYTE(m_len); LZO_STATS(lzo_stats->m4_matches++); } m_off -= M3_MIN_OFFSET - M3_EOF_OFFSET; /* code low offset bits */ *op++ = LZO_BYTE(m_off & M3O_MASK); /* code high offset bits */ *op++ = LZO_BYTE(m_off >> M3O_BITS); #if defined(LZO_HAVE_M3) m3 = op; /* set M3 pointer */ #endif 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 */