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+/* lzo1b_c.ch -- implementation of the LZO1B compression algorithm
+
+ This file is part of the LZO real-time data compression library.
+
+ 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/
+ */
+
+
+
+/***********************************************************************
+//
+************************************************************************/
+
+#if !defined(LZO_HAVE_R1) && !defined(LZO_NO_R1)
+# define LZO_HAVE_R1
+#endif
+
+#if !defined(LZO_HAVE_M3) && !defined(LZO_NO_M3)
+# if (M3O_BITS < 8)
+# define LZO_HAVE_M3
+# endif
+#endif
+
+
+#define MI
+#define SI MI
+#if (DD_BITS > 0)
+#define DI ++ii; DVAL_NEXT(dv,ii); UPDATE_D(dict,drun,dv,ii,in); MI
+#define XI assert(ii < ip); ii = ip; DVAL_FIRST(dv,(ip));
+#else
+#define DI ++ii; DINDEX1(dindex,ii); UPDATE_I(dict,0,dindex,ii,in); MI
+#define XI assert(ii < ip); ii = ip;
+#endif
+
+
+/***********************************************************************
+// compress a block of data.
+//
+// I really apologize for this spaghetti code.
+************************************************************************/
+
+LZO_PRIVATE(int)
+do_compress ( const lzo_bytep in , lzo_uint in_len,
+ lzo_bytep out, lzo_uintp out_len,
+ lzo_voidp wrkmem )
+{
+ register const lzo_bytep ip;
+#if (DD_BITS > 0)
+#if defined(__LZO_HASH_INCREMENTAL)
+ lzo_xint dv;
+#endif
+ unsigned drun = 0;
+#endif
+ lzo_bytep op;
+ const lzo_bytep const in_end = in + in_len;
+ const lzo_bytep const ip_end = in + in_len - MIN_LOOKAHEAD;
+ const lzo_bytep ii;
+#if defined(LZO_HAVE_R1)
+ const lzo_bytep r1 = ip_end; /* pointer for R1 match (none yet) */
+#endif
+#if defined(LZO_HAVE_M3)
+ lzo_bytep m3 = out + 1; /* pointer after last m3/m4 match */
+#endif
+
+ lzo_dict_p const dict = (lzo_dict_p) wrkmem;
+
+
+#if defined(LZO_COLLECT_STATS)
+ lzo_stats->r_bits = R_BITS;
+ lzo_stats->m3o_bits = M3O_BITS;
+ lzo_stats->dd_bits = DD_BITS;
+ lzo_stats->clevel = CLEVEL;
+ lzo_stats->d_bits = D_BITS;
+ lzo_stats->min_lookahead = MIN_LOOKAHEAD;
+ lzo_stats->max_lookbehind = MAX_LOOKBEHIND;
+ lzo_stats->compress_id = LZO_CPP_MACRO_EXPAND(COMPRESS_ID);
+#endif
+
+ /* init dictionary */
+#if defined(LZO_DETERMINISTIC)
+ BZERO8_PTR(wrkmem,sizeof(lzo_dict_t),D_SIZE);
+#endif
+
+
+ op = out;
+ ip = in;
+ ii = ip; /* point to start of current literal run */
+
+
+#if (DD_BITS > 0)
+ DVAL_FIRST(dv,ip);
+ UPDATE_D(dict,drun,dv,ip,in);
+ ip++;
+ DVAL_NEXT(dv,ip);
+#else
+ ip++;
+#endif
+
+ assert(ip < ip_end);
+ for (;;)
+ {
+ const lzo_bytep m_pos;
+#if !defined(NDEBUG)
+ const lzo_bytep m_pos_sav = NULL;
+#endif
+ lzo_uint m_off;
+#if (DD_BITS == 0)
+ lzo_uint dindex;
+#endif
+ lzo_uint m_len;
+
+
+/***********************************************************************
+// search for a match
+************************************************************************/
+
+#if !defined(LZO_SEARCH_MATCH_INCLUDE_FILE)
+# define LZO_SEARCH_MATCH_INCLUDE_FILE "lzo1b_sm.ch"
+#endif
+
+#include LZO_SEARCH_MATCH_INCLUDE_FILE
+
+
+#if !defined(LZO_TEST_MATCH_INCLUDE_FILE)
+# define LZO_TEST_MATCH_INCLUDE_FILE "lzo1b_tm.ch"
+#endif
+
+#include LZO_TEST_MATCH_INCLUDE_FILE
+
+
+
+/***********************************************************************
+// found a literal
+************************************************************************/
+
+
+ /* a literal */
+literal:
+#if (DD_BITS == 0)
+ UPDATE_I(dict,0,dindex,ip,in);
+#endif
+ if (++ip >= ip_end)
+ break;
+#if (DD_BITS > 0)
+ DVAL_NEXT(dv,ip);
+#endif
+ continue;
+
+
+
+/***********************************************************************
+// found a match
+************************************************************************/
+
+match:
+#if (DD_BITS == 0)
+ UPDATE_I(dict,0,dindex,ip,in);
+#endif
+ /* we have found a match of at least M2_MIN_LEN */
+
+
+#if !defined(LZO_CODE_RUN_INCLUDE_FILE)
+# define LZO_CODE_RUN_INCLUDE_FILE "lzo1b_cr.ch"
+#endif
+
+#include LZO_CODE_RUN_INCLUDE_FILE
+
+
+ /* ii now points to the start of the current match */
+ assert(ii == ip);
+
+
+/***********************************************************************
+// code the match
+************************************************************************/
+
+#if !defined(LZO_CODE_MATCH_INCLUDE_FILE)
+# define LZO_CODE_MATCH_INCLUDE_FILE "lzo1b_cm.ch"
+#endif
+
+#include LZO_CODE_MATCH_INCLUDE_FILE
+
+
+ /* ii now points to the start of the next literal run */
+ assert(ii == ip);
+
+ }
+
+
+/***********************************************************************
+// end of block
+************************************************************************/
+
+ assert(ip <= in_end);
+
+#if defined(LZO_COLLECT_STATS)
+ {
+ lzo_uint i;
+ const lzo_bytep p;
+
+ for (i = 0; i < D_SIZE; i++)
+ {
+ p = dict[i];
+ if (BOUNDS_CHECKING_OFF_IN_EXPR(p == NULL || p < in || p > in_end))
+ lzo_stats->unused_dict_entries++;
+ }
+ lzo_stats->unused_dict_entries_percent =
+ 100.0 * lzo_stats->unused_dict_entries / D_SIZE;
+ }
+#endif
+
+
+#if defined(LZO_RETURN_IF_NOT_COMPRESSIBLE)
+ /* return if op == out to indicate that we
+ * couldn't compress and didn't copy anything.
+ */
+ if (op == out)
+ {
+ *out_len = 0;
+ return LZO_E_NOT_COMPRESSIBLE;
+ }
+#endif
+
+ /* store the final literal run */
+ if (pd(in_end,ii) > 0)
+ {
+ lzo_uint t = pd(in_end,ii);
+ op = STORE_RUN(op,ii,t);
+ }
+
+ *out_len = pd(op, out);
+ return LZO_E_OK; /* compression went ok */
+}
+
+
+/*
+vi:ts=4:et
+*/
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