lzo1x_c.cpp

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/*
**  Command & Conquer Generals Zero Hour(tm)
**  Copyright 2025 Electronic Arts Inc.
**
**  This program 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 3 of the License, or
**  (at your option) any later version.
**
**  This program 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 this program.  If not, see <http://www.gnu.org/licenses/>.
*/
 
/*********************************************************************************************** 
 ***              C O N F I D E N T I A L  ---  W E S T W O O D  S T U D I O S               *** 
 *********************************************************************************************** 
 *                                                                                             * 
 *                 Project Name : Command & Conquer                                            * 
 *                                                                                             * 
 *                     $Archive:: /Commando/Code/wwlib/lzo1x_c.cpp                            $* 
 *                                                                                             * 
 *                      $Author:: Jani_p                                                      $*
 *                                                                                             * 
 *                     $Modtime:: 6/28/00 10:13a                                              $*
 *                                                                                             * 
 *                    $Revision:: 2                                                           $*
 *                                                                                             *
 *---------------------------------------------------------------------------------------------* 
 * Functions:                                                                                  * 
 * - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
 
/* $Header: /Commando/Code/wwlib/lzo1x_c.cpp 2     7/05/00 6:26p Jani_p $ */
/* lzo1x_c.c -- standalone LZO1X-1 compressor
 
   This file is part of the LZO real-time data compression library.
 
   Copyright (C) 1996 Markus Franz Xaver Johannes Oberhumer
 
   The LZO library is free software; you can redistribute it and/or
   modify it under the terms of the GNU Library 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
   Library General Public License for more details.
 
   You should have received a copy of the GNU Library General Public
   License along with the LZO library; see the file COPYING.LIB.
   If not, write to the Free Software Foundation, Inc.,
   675 Mass Ave, Cambridge, MA 02139, USA.
 
   Markus F.X.J. Oberhumer
   markus.oberhumer@jk.uni-linz.ac.at
 */
 
#include    "always.h"
#include    "lzo1x.h"
#include    "lzo_conf.h"
#include "wwdebug.h"
#include    <assert.h>
 
#if !defined(LZO1X) && !defined(LZO1Y)
#  define LZO1X
#endif
 
 
/***********************************************************************
//
************************************************************************/
 
#define M1_MAX_OFFSET   0x0400
#if defined(LZO1X)
#define M2_MAX_OFFSET   0x0800
#elif defined(LZO1Y)
#define M2_MAX_OFFSET   0x0400
#endif
#define M3_MAX_OFFSET   0x4000
#define M4_MAX_OFFSET   0xbfff
 
#define MX_MAX_OFFSET   (M1_MAX_OFFSET + M2_MAX_OFFSET)
 
#define M1_MARKER       0
#define M2_MARKER       64
#define M3_MARKER       32
#define M4_MARKER       16
 
 
#define _DV2(p,shift1,shift2) \
        (((( (lzo_uint)(p[2]) << shift1) ^ p[1]) << shift2) ^ p[0])
#define DVAL_NEXT(dv,p) \
        dv ^= p[-1]; dv = (((dv) >> 5) ^ ((lzo_uint)(p[2]) << (2*5)))
#define _DV(p,shift)        _DV2(p,shift,shift)
#define DVAL_FIRST(dv,p)    dv = _DV((p),5)
#define _DINDEX(dv,p)       ((40799u * (dv)) >> 5)
#define DINDEX(dv,p)        (((_DINDEX(dv,p)) & 0x3fff) << 0)
#define UPDATE_D(dict,cycle,dv,p)       dict[ DINDEX(dv,p) ] = (p)
#define UPDATE_I(dict,cycle,index,p)    dict[index] = (p)
 
 
/***********************************************************************
// compress a block of data.
************************************************************************/
static int do_compress(const lzo_byte * in, lzo_uint  in_len,
    lzo_byte *out, lzo_uint *out_len,
    lzo_voidp wrkmem )
{
 
    register const lzo_byte *ip;
    lzo_uint dv;
    lzo_byte *op;
    const lzo_byte * const in_end = in + in_len;
    const lzo_byte * const ip_end = in + in_len - 9 - 4;
    const lzo_byte *ii;
    const lzo_bytepp const dict = (const lzo_bytepp) wrkmem;
 
    op = out;
    ip = in;
    ii = ip;
 
    DVAL_FIRST(dv,ip); UPDATE_D(dict,cycle,dv,ip); ip++;
    DVAL_NEXT(dv,ip);  UPDATE_D(dict,cycle,dv,ip); ip++;
    DVAL_NEXT(dv,ip);  UPDATE_D(dict,cycle,dv,ip); ip++;
    DVAL_NEXT(dv,ip);  UPDATE_D(dict,cycle,dv,ip); ip++;
 
    for (;;) {
        register const lzo_byte *m_pos;
        lzo_uint m_len;
        lzo_ptrdiff_t m_off;
        lzo_uint lit;
 
        lzo_uint dindex = DINDEX(dv,ip);
        m_pos = dict[dindex];
        UPDATE_I(dict,cycle,dindex,ip);
 
 
        if (LZO_CHECK_MPOS_NON_DET(m_pos,m_off,in,ip,M4_MAX_OFFSET)) {
        }
#if defined(LZO_UNALIGNED_OK_2)
        else
            if (* (unsigned short *) m_pos != * (unsigned short *) ip)
#else
        else
            if (m_pos[0] != ip[0] || m_pos[1] != ip[1])
#endif
        {
        } else {
            if (m_pos[2] == ip[2]) {
                lit = ip - ii;
                m_pos += 3;
                if (m_off <= M2_MAX_OFFSET)
                    goto match;
 
                /* better compression, but slower */
                if (lit == 3) {
                    assert(op - 2 > out); op[-2] |= LZO_BYTE(3);
                    *op++ = *ii++; *op++ = *ii++; *op++ = *ii++;
                    goto code_match;
                }
 
                if (*m_pos == ip[3]) {
                    goto match;
                }
            } else {
                /* still need a better way for finding M1 matches */
            }
        }
 
 
    /* a literal */
        ++ip;
        if (ip >= ip_end) {
            break;
        }
        DVAL_NEXT(dv,ip);
        continue;
 
 
    /* a match */
 
match:
 
        /* store current literal run */
        if (lit > 0) {
            register lzo_uint t = lit;
 
            if (t <= 3) {
                assert(op - 2 > out);
                op[-2] |= LZO_BYTE(t);
            } else {
                if (t <= 18) {
                    *op++ = LZO_BYTE(t - 3);
                } else {
                    register lzo_uint tt = t - 18;
 
                    *op++ = 0;
                    while (tt > 255) {
                        tt -= 255;
                        *op++ = 0;
                    }
                    assert(tt > 0);
                    *op++ = LZO_BYTE(tt);
                }
            }
 
            do {
                *op++ = *ii++;
            } while (--t > 0);
        }
 
 
        /* code the match */
code_match:
        assert(ii == ip);
        ip += 3;
        if (*m_pos++ != *ip++ || *m_pos++ != *ip++ || *m_pos++ != *ip++ ||
            *m_pos++ != *ip++ || *m_pos++ != *ip++ || *m_pos++ != *ip++)
        {
            --ip;
            m_len = ip - ii;
            assert(m_len >= 3); assert(m_len <= 8);
 
            if (m_off <= M2_MAX_OFFSET) {
                m_off -= 1;
                *op++ = LZO_BYTE(((m_len - 1) << 5) | ((m_off & 7) << 2));
                *op++ = LZO_BYTE(m_off >> 3);
            } else {
                if (m_off <= M3_MAX_OFFSET) {
                    m_off -= 1;
                    *op++ = LZO_BYTE(M3_MARKER | (m_len - 2));
                    goto m3_m4_offset;
                } else {
                    m_off -= 0x4000;
                    assert(m_off > 0); assert(m_off <= 0x7fff);
                    *op++ = LZO_BYTE(M4_MARKER |
                                     ((m_off & 0x4000) >> 11) | (m_len - 2));
                    goto m3_m4_offset;
                }
            }
        } else {
            const lzo_byte *end;
            end = in_end;
            while (ip < end && *m_pos == *ip) {
                m_pos++;
                ip++;
            }
            m_len = (ip - ii);
            assert(m_len >= 3);
 
            if (m_off <= M3_MAX_OFFSET) {
                m_off -= 1;
                if (m_len <= 33) {
                    *op++ = LZO_BYTE(M3_MARKER | (m_len - 2));
                } else {
                    m_len -= 33;
                    *op++ = M3_MARKER | 0;
                    goto m3_m4_len;
                }
            } else {
                m_off -= 0x4000;
                assert(m_off > 0); assert(m_off <= 0x7fff);
                if (m_len <= 9) {
                    *op++ = LZO_BYTE(M4_MARKER |
                                     ((m_off & 0x4000) >> 11) | (m_len - 2));
                } else {
                    m_len -= 9;
                    *op++ = LZO_BYTE(M4_MARKER | ((m_off & 0x4000) >> 11));
m3_m4_len:
                    while (m_len > 255) {
                        m_len -= 255;
                        *op++ = 0;
                    }
                    assert(m_len > 0);
                    *op++ = LZO_BYTE(m_len);
                }
            }
 
m3_m4_offset:
            *op++ = LZO_BYTE((m_off & 63) << 2);
            *op++ = LZO_BYTE(m_off >> 6);
        }
 
        ii = ip;
        if (ip >= ip_end) {
            break;
        }
        DVAL_FIRST(dv,ip);
    }
 
    /* store final literal run */
    if (in_end - ii > 0) {
        register lzo_uint t = in_end - ii;
 
        if (op == out && t <= 238) {
            *op++ = LZO_BYTE(17 + t);
        } else {
            if (t <= 3) {
                op[-2] |= LZO_BYTE(t);
            } else {
                if (t <= 18) {
                    *op++ = LZO_BYTE(t - 3);
                } else {
                    register lzo_uint tt = t - 18;
 
                    *op++ = 0;
                    while (tt > 255) {
                        tt -= 255;
                        *op++ = 0;
                    }
                    assert(tt > 0);
                    *op++ = LZO_BYTE(tt);
                }
            }
        }
        do {
            *op++ = *ii++;
        } while (--t > 0);
    }
 
    *out_len = op - out;
    return LZO_E_OK;
}
 
 
/***********************************************************************
// public entry point
************************************************************************/
 
int lzo1x_1_compress     ( const lzo_byte * in, lzo_uint  in_len,
                                 lzo_byte * out, lzo_uint *out_len,
                                 lzo_voidp wrkmem )
{
    lzo_byte *op = out;
    int r = LZO_E_OK;
 
    if (in_len <= 0) {
        *out_len = 0;
    } else {
        if (in_len <= 9 + 4) {
            *op++ = LZO_BYTE(17 + in_len);
            do *op++ = *in++; while (--in_len > 0);
            *out_len = op - out;
        } else {
            r = do_compress(in,in_len,out,out_len,wrkmem);
        }
    }
 
    if (r == LZO_E_OK) {
        op = out + *out_len;
        *op++ = M4_MARKER | 1;
        *op++ = 0;
        *op = 0;
        *out_len += 3;
    }
 
    return r;
}
 
 
/*
vi:ts=4
*/