datalore/CnC_Red_Alert
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity
main
CnC_Red_Alert/CODE/LZO1X_C.CPP

350 lines
8.0 KiB
C++
Raw Permalink Blame History

/*
** Command & Conquer Red Alert(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/>.
*/
/* 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 "lzo1x.h"
#define NDEBUG
#include <assert.h>
#include "lzo_conf.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++;
while (1) {
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
*/
Reference in New Issue View Git Blame Copy Permalink