Blame src/lzo_mchw.ch

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/* 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) 1996-2014 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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/***********************************************************************
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//
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************************************************************************/
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typedef struct
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{
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    unsigned 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_bytep bp;
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    const lzo_bytep ip;
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    const lzo_bytep in;
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    const lzo_bytep in_end;
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    lzo_bytep out;
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    lzo_callback_p 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_bytep 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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#define getbyte(c)  ((c).ip < (c).in_end ? *((c).ip)++ : (-1))
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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_p s,
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             const lzo_bytep dict, lzo_uint dict_len,
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             lzo_uint32_t 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 != LZO_E_OK)
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    {
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        swd_exit(s);
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        return r;
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    }
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    s->use_best_off = (flags & 1) ? 1 : 0;
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    return LZO_E_OK;
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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_p 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 = SWD_THRESHOLD;
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    s->m_off = 0;
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#ifdef SWD_BEST_OFF
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    if (s->use_best_off)
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        lzo_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 > SWD_THRESHOLD && c->m_len + 1 <= c->look)
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    {
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        const lzo_bytep ip = c->bp;
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        const lzo_bytep m  = c->bp - c->m_off;
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        const lzo_bytep in = c->in;
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        if (ip - in > s->swd_n)
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            in = ip - s->swd_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 (lzo_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->cb->nprogress && c->textsize > c->printcount)
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    {
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        (*c->cb->nprogress)(c->cb, c->textsize, c->codesize, 0);
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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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