231 lines
4.5 KiB
Plaintext
231 lines
4.5 KiB
Plaintext
/* lzo_mchw.ch -- matching functions using a window
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This file is part of the LZO real-time data compression library.
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Copyright (C) 1996-2002 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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59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
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Markus F.X.J. Oberhumer
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<markus@oberhumer.com>
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*/
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/***********************************************************************
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//
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************************************************************************/
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typedef struct
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{
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int init;
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lzo_uint look; /* bytes in lookahead buffer */
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lzo_uint m_len;
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lzo_uint m_off;
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lzo_uint last_m_len;
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lzo_uint last_m_off;
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const lzo_byte *bp;
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const lzo_byte *ip;
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const lzo_byte *in;
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const lzo_byte *in_end;
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lzo_byte *out;
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lzo_progress_callback_t cb;
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lzo_uint textsize; /* text size counter */
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lzo_uint codesize; /* code size counter */
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lzo_uint printcount; /* counter for reporting progress every 1K bytes */
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/* some stats */
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unsigned long lit_bytes;
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unsigned long match_bytes;
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unsigned long rep_bytes;
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unsigned long lazy;
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#if defined(LZO1B)
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lzo_uint r1_m_len;
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/* some stats */
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unsigned long r1_r, m3_r, m2_m, m3_m;
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#endif
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#if defined(LZO1C)
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lzo_uint r1_m_len;
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lzo_byte *m3;
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/* some stats */
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unsigned long r1_r, m3_r, m2_m, m3_m;
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#endif
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#if defined(LZO1F)
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lzo_uint r1_lit;
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lzo_uint r1_m_len;
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/* some stats */
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unsigned long r1_r, m2_m, m3_m;
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#endif
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#if defined(LZO1X) || defined(LZO1Y) || defined(LZO1Z)
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lzo_uint r1_lit;
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lzo_uint r1_m_len;
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/* some stats */
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unsigned long m1a_m, m1b_m, m2_m, m3_m, m4_m;
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unsigned long lit1_r, lit2_r, lit3_r;
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#endif
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#if defined(LZO2A)
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/* some stats */
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unsigned long m1, m2, m3, m4;
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#endif
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}
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LZO_COMPRESS_T;
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#if defined(__PUREC__)
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/* the cast is needed to work around a bug in Pure C (Atari ST) */
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#define getbyte(c) ((c).ip < (c).in_end ? (unsigned) *((c).ip)++ : (-1))
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#else
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#define getbyte(c) ((c).ip < (c).in_end ? *((c).ip)++ : (-1))
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#endif
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#include "lzo_swd.ch"
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/***********************************************************************
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//
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************************************************************************/
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static int
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init_match ( LZO_COMPRESS_T *c, lzo_swd_t *s,
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const lzo_byte *dict, lzo_uint dict_len,
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lzo_uint32 flags )
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{
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int r;
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assert(!c->init);
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c->init = 1;
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s->c = c;
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c->last_m_len = c->last_m_off = 0;
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c->textsize = c->codesize = c->printcount = 0;
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c->lit_bytes = c->match_bytes = c->rep_bytes = 0;
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c->lazy = 0;
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r = swd_init(s,dict,dict_len);
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if (r != 0)
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return r;
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s->use_best_off = (flags & 1) ? 1 : 0;
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return r;
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}
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/***********************************************************************
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//
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************************************************************************/
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static int
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find_match ( LZO_COMPRESS_T *c, lzo_swd_t *s,
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lzo_uint this_len, lzo_uint skip )
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{
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assert(c->init);
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if (skip > 0)
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{
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assert(this_len >= skip);
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swd_accept(s, this_len - skip);
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c->textsize += this_len - skip + 1;
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}
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else
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{
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assert(this_len <= 1);
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c->textsize += this_len - skip;
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}
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s->m_len = 1;
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s->m_len = THRESHOLD;
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#ifdef SWD_BEST_OFF
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if (s->use_best_off)
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memset(s->best_pos,0,sizeof(s->best_pos));
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#endif
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swd_findbest(s);
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c->m_len = s->m_len;
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c->m_off = s->m_off;
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swd_getbyte(s);
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if (s->b_char < 0)
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{
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c->look = 0;
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c->m_len = 0;
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swd_exit(s);
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}
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else
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{
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c->look = s->look + 1;
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}
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c->bp = c->ip - c->look;
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#if 0
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/* brute force match search */
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if (c->m_len > THRESHOLD && c->m_len + 1 <= c->look)
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{
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const lzo_byte *ip = c->bp;
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const lzo_byte *m = c->bp - c->m_off;
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const lzo_byte *in = c->in;
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if (ip - in > N)
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in = ip - N;
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for (;;)
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{
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while (*in != *ip)
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in++;
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if (in == ip)
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break;
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if (in != m)
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if (memcmp(in,ip,c->m_len+1) == 0)
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printf("%p %p %p %5d\n",in,ip,m,c->m_len);
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in++;
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}
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}
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#endif
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if (c->cb && c->textsize > c->printcount)
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{
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(*c->cb)(c->textsize,c->codesize);
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c->printcount += 1024;
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}
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return LZO_E_OK;
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}
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/*
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vi:ts=4:et
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*/
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