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/* ucl_mchw.ch -- matching functions using a window

   This file is part of the UCL data compression library.

   Copyright (C) 1996-2002 Markus Franz Xaver Johannes Oberhumer

   All Rights Reserved.

   The UCL 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 UCL 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 UCL library; see the file COPYING.

   If not, write to the Free Software Foundation, Inc.,

   59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.

   Markus F.X.J. Oberhumer

   <markus@oberhumer.com>

 */

/***********************************************************************

//

************************************************************************/

typedef struct

{

    int init;

    ucl_uint look;          /* bytes in lookahead buffer */

    ucl_uint m_len;

    ucl_uint m_off;

    ucl_uint last_m_len;

    ucl_uint last_m_off;

    const ucl_byte *bp;

    const ucl_byte *ip;

    const ucl_byte *in;

    const ucl_byte *in_end;

    ucl_byte *out;

    ucl_uint32 bb_b;

    unsigned bb_k;

    unsigned bb_c_endian;

    unsigned bb_c_s;

    unsigned bb_c_s8;

    ucl_byte *bb_p;

    ucl_byte *bb_op;

    struct ucl_compress_config_t conf;

    ucl_uintp result;

    ucl_progress_callback_p cb;

    ucl_uint textsize;      /* text size counter */

    ucl_uint codesize;      /* code size counter */

    ucl_uint printcount;    /* counter for reporting progress every 1K bytes */

    /* some stats */

    unsigned long lit_bytes;

    unsigned long match_bytes;

    unsigned long rep_bytes;

    unsigned long lazy;

}

UCL_COMPRESS_T;

#if defined(__PUREC__) && defined(__UCL_TOS16)

/* the cast is needed to work around a bug in Pure C */

#define getbyte(c)  ((c).ip < (c).in_end ? (unsigned) *((c).ip)++ : (-1))

#else

#define getbyte(c)  ((c).ip < (c).in_end ? *((c).ip)++ : (-1))

#endif

#include "ucl_swd.ch"

/***********************************************************************

//

************************************************************************/

static int

init_match ( UCL_COMPRESS_T *c, ucl_swd_t *s,

             const ucl_byte *dict, ucl_uint dict_len,

             ucl_uint32 flags )

{

    int r;

    assert(!c->init);

    c->init = 1;

    s->c = c;

    c->last_m_len = c->last_m_off = 0;

    c->textsize = c->codesize = c->printcount = 0;

    c->lit_bytes = c->match_bytes = c->rep_bytes = 0;

    c->lazy = 0;

    r = swd_init(s,dict,dict_len);

    if (r != UCL_E_OK)

    {

        swd_exit(s);

        return r;

    }

    s->use_best_off = (flags & 1) ? 1 : 0;

    return UCL_E_OK;

}

/***********************************************************************

//

************************************************************************/

static int

find_match ( UCL_COMPRESS_T *c, ucl_swd_t *s,

             ucl_uint this_len, ucl_uint skip )

{

    assert(c->init);

    if (skip > 0)

    {

        assert(this_len >= skip);

        swd_accept(s, this_len - skip);

        c->textsize += this_len - skip + 1;

    }

    else

    {

        assert(this_len <= 1);

        c->textsize += this_len - skip;

    }

    s->m_len = THRESHOLD;

#ifdef SWD_BEST_OFF

    if (s->use_best_off)

        memset(s->best_pos,0,sizeof(s->best_pos));

#endif

    swd_findbest(s);

    c->m_len = s->m_len;

#if defined(__UCL_CHECKER)

    /* s->m_off may be uninitialized if we didn't find a match,

     * but then its value will never be used.

     */

    c->m_off = (s->m_len == THRESHOLD) ? 0 : s->m_off;

#else

    c->m_off = s->m_off;

#endif

    swd_getbyte(s);

    if (s->b_char < 0)

    {

        c->look = 0;

        c->m_len = 0;

        swd_exit(s);

    }

    else

    {

        c->look = s->look + 1;

    }

    c->bp = c->ip - c->look;

#if 0

    /* brute force match search */

    if (c->m_len > THRESHOLD && c->m_len + 1 <= c->look)

    {

        const ucl_byte *ip = c->bp;

        const ucl_byte *m  = c->bp - c->m_off;

        const ucl_byte *in = c->in;

        if (ip - in > N)

            in = ip - N;

        for (;;)

        {

            while (*in != *ip)

                in++;

            if (in == ip)

                break;

            if (in != m)

                if (memcmp(in,ip,c->m_len+1) == 0)

                    printf("%p %p %p %5d\n",in,ip,m,c->m_len);

            in++;

        }

    }

#endif

    if (c->cb && c->textsize > c->printcount)

    {

        (*c->cb->callback)(c->textsize,c->codesize,3,c->cb->user);

        c->printcount += 1024;

    }

    return UCL_E_OK;

}

/***********************************************************************

// bit buffer

************************************************************************/

static int bbConfig(UCL_COMPRESS_T *c, int endian, int bitsize)

{

    if (endian != -1)

    {

        if (endian != 0)

            return UCL_E_ERROR;

        c->bb_c_endian = endian;

    }

    if (bitsize != -1)

    {

        if (bitsize != 8 && bitsize != 16 && bitsize != 32)

            return UCL_E_ERROR;

        c->bb_c_s = bitsize;

        c->bb_c_s8 = bitsize / 8;

    }

    c->bb_b = 0; c->bb_k = 0;

    c->bb_p = NULL;

    c->bb_op = NULL;

    return UCL_E_OK;

}

static void bbWriteBits(UCL_COMPRESS_T *c)

{

    ucl_byte *p = c->bb_p;

    ucl_uint32 b = c->bb_b;

    p[0] = UCL_BYTE(b >>  0);

    if (c->bb_c_s >= 16)

    {

        p[1] = UCL_BYTE(b >>  8);

        if (c->bb_c_s == 32)

        {

            p[2] = UCL_BYTE(b >> 16);

            p[3] = UCL_BYTE(b >> 24);

        }

    }

}

static void bbPutBit(UCL_COMPRESS_T *c, unsigned bit)

{

    assert(bit == 0 || bit == 1);

    assert(c->bb_k <= c->bb_c_s);

    if (c->bb_k < c->bb_c_s)

    {

        if (c->bb_k == 0)

        {

            assert(c->bb_p == NULL);

            c->bb_p = c->bb_op;

            c->bb_op += c->bb_c_s8;

        }

        assert(c->bb_p != NULL);

        assert(c->bb_p + c->bb_c_s8 <= c->bb_op);

        c->bb_b = (c->bb_b << 1) + bit;

        c->bb_k++;

    }

    else

    {

        assert(c->bb_p != NULL);

        assert(c->bb_p + c->bb_c_s8 <= c->bb_op);

        bbWriteBits(c);

        c->bb_p = c->bb_op;

        c->bb_op += c->bb_c_s8;

        c->bb_b = bit;

        c->bb_k = 1;

    }

}

static void bbPutByte(UCL_COMPRESS_T *c, unsigned b)

{

    /**printf("putbyte %p %p %x  (%d)\n", op, bb_p, x, bb_k);*/

    assert(c->bb_p == NULL || c->bb_p + c->bb_c_s8 <= c->bb_op);

    *c->bb_op++ = UCL_BYTE(b);

}

static void bbFlushBits(UCL_COMPRESS_T *c, unsigned filler_bit)

{

    if (c->bb_k > 0)

    {

        assert(c->bb_k <= c->bb_c_s);

        while (c->bb_k != c->bb_c_s)

            bbPutBit(c, filler_bit);

        bbWriteBits(c);

        c->bb_k = 0;

    }

    c->bb_p = NULL;

}

/*

vi:ts=4:et

*/