355 lines
7.7 KiB
C
355 lines
7.7 KiB
C
/* lzo2a_9x.c -- implementation of the LZO2A-999 compression algorithm
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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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#include <lzoconf.h>
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#if !defined(LZO_999_UNSUPPORTED)
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#include <stdio.h>
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#include "config2a.h"
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#if 0
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#undef NDEBUG
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#include <assert.h>
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#endif
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/***********************************************************************
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//
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************************************************************************/
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#define THRESHOLD 1 /* lower limit for match length */
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#define F 2048 /* upper limit for match length */
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#define LZO2A
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#define LZO_COMPRESS_T lzo2a_999_t
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#define lzo_swd_t lzo2a_999_swd_t
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#include "lzo_mchw.ch"
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/***********************************************************************
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//
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************************************************************************/
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#define putbyte(x) *op++ = LZO_BYTE(x)
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#define putbits(j,x) \
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if (k == 0) bitp = op++; \
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SETBITS(j,x); \
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if (k >= 8) { *bitp = LZO_BYTE(MASKBITS(8)); DUMPBITS(8); \
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if (k > 0) bitp = op++; }
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#define putbit(x) putbits(1,x)
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/***********************************************************************
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// this is a public function, but there is no prototype in a header file
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************************************************************************/
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LZO_EXTERN(int)
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lzo2a_999_compress_callback ( const lzo_byte *in , lzo_uint in_len,
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lzo_byte *out, lzo_uintp out_len,
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lzo_voidp wrkmem,
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lzo_progress_callback_t cb,
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lzo_uint max_chain );
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LZO_PUBLIC(int)
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lzo2a_999_compress_callback ( const lzo_byte *in , lzo_uint in_len,
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lzo_byte *out, lzo_uintp out_len,
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lzo_voidp wrkmem,
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lzo_progress_callback_t cb,
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lzo_uint max_chain )
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{
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lzo_byte *op;
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lzo_byte *bitp = 0;
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lzo_uint m_len, m_off;
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LZO_COMPRESS_T cc;
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LZO_COMPRESS_T * const c = &cc;
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lzo_swd_t * const swd = (lzo_swd_t *) wrkmem;
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int r;
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lzo_uint32 b = 0; /* bit buffer */
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unsigned k = 0; /* bits in bit buffer */
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#if defined(__LZO_QUERY_COMPRESS)
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if (__LZO_IS_COMPRESS_QUERY(in,in_len,out,out_len,wrkmem))
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return __LZO_QUERY_COMPRESS(in,in_len,out,out_len,wrkmem,1,lzo_sizeof(lzo_swd_t));
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#endif
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/* sanity check */
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if (!lzo_assert(LZO2A_999_MEM_COMPRESS >= lzo_sizeof(lzo_swd_t)))
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return LZO_E_ERROR;
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c->init = 0;
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c->ip = c->in = in;
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c->in_end = in + in_len;
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c->cb = cb;
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c->m1 = c->m2 = c->m3 = c->m4 = 0;
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op = out;
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r = init_match(c,swd,NULL,0,0);
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if (r != 0)
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return r;
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if (max_chain > 0)
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swd->max_chain = max_chain;
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r = find_match(c,swd,0,0);
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if (r != 0)
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return r;
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while (c->look > 0)
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{
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int lazy_match_min_gain = 0;
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int extra1 = 0;
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int extra2 = 0;
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lzo_uint ahead = 0;
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LZO_UNUSED(extra1);
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m_len = c->m_len;
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m_off = c->m_off;
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#if (N >= 8192)
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if (m_off >= 8192)
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{
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if (m_len < M3_MIN_LEN)
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m_len = 0;
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else
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lazy_match_min_gain = 1;
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}
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else
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#endif
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if (m_len >= M1_MIN_LEN && m_len <= M1_MAX_LEN && m_off <= 256)
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{
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lazy_match_min_gain = 2;
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extra1 = 3;
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extra2 = 2;
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}
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else if (m_len >= 10)
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lazy_match_min_gain = 1;
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else if (m_len >= 3)
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{
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lazy_match_min_gain = 1;
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extra1 = 1;
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}
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else
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m_len = 0;
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/* try a lazy match */
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if (lazy_match_min_gain > 0 && c->look > m_len)
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{
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int lit = swd->b_char;
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r = find_match(c,swd,1,0);
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assert(r == 0);
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assert(c->look > 0);
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#if (N >= 8192)
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if (m_off < 8192 && c->m_off >= 8192)
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lazy_match_min_gain += extra1;
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else
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#endif
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if (m_len >= M1_MIN_LEN && m_len <= M1_MAX_LEN && m_off <= 256)
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{
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if (!(c->m_len >= M1_MIN_LEN &&
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c->m_len <= M1_MAX_LEN && c->m_off <= 256))
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lazy_match_min_gain += extra2;
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}
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if (c->m_len >= M1_MIN_LEN &&
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c->m_len <= M1_MAX_LEN && c->m_off <= 256)
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{
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lazy_match_min_gain -= 1;
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}
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if (lazy_match_min_gain < 1)
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lazy_match_min_gain = 1;
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if (c->m_len >= m_len + lazy_match_min_gain)
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{
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c->lazy++;
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#if !defined(NDEBUG)
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m_len = c->m_len;
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m_off = c->m_off;
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assert(lzo_memcmp(c->ip - c->look, c->ip - c->look - m_off,
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m_len) == 0);
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assert(m_len >= 3 || (m_len >= 2 && m_off <= 256));
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#endif
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/* code literal */
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putbit(0);
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putbyte(lit);
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c->lit_bytes++;
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continue;
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}
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else
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ahead = 1;
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assert(m_len > 0);
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}
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if (m_len == 0)
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{
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/* a literal */
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putbit(0);
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putbyte(swd->b_char);
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c->lit_bytes++;
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r = find_match(c,swd,1,0);
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assert(r == 0);
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}
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else
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{
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assert(m_len >= M1_MIN_LEN);
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assert(m_off > 0);
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assert(m_off <= N);
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/* 2 - code match */
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if (m_len >= M1_MIN_LEN && m_len <= M1_MAX_LEN && m_off <= 256)
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{
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putbit(1);
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putbit(0);
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putbits(2,m_len - M1_MIN_LEN);
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putbyte(m_off - 1);
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c->m1++;
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}
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#if (N >= 8192)
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else if (m_off >= 8192)
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{
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unsigned len = m_len;
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assert(m_len >= M3_MIN_LEN);
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putbit(1);
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putbit(1);
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putbyte(m_off & 31);
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putbyte(m_off >> 5);
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putbit(1);
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len -= M3_MIN_LEN - 1;
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while (len > 255)
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{
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len -= 255;
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putbyte(0);
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}
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putbyte(len);
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c->m4++;
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}
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#endif
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else
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{
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assert(m_len >= 3);
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putbit(1);
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putbit(1);
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if (m_len <= 9)
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{
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putbyte(((m_len - 2) << 5) | (m_off & 31));
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putbyte(m_off >> 5);
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c->m2++;
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}
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else
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{
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lzo_uint len = m_len;
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putbyte(m_off & 31);
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putbyte(m_off >> 5);
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#if (N >= 8192)
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putbit(0);
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#endif
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len -= 10 - 1;
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while (len > 255)
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{
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len -= 255;
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putbyte(0);
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}
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putbyte(len);
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c->m3++;
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}
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}
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r = find_match(c,swd,m_len,1+ahead);
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assert(r == 0);
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}
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c->codesize = op - out;
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}
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#if defined(LZO_EOF_CODE)
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/* code EOF code */
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putbit(1);
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putbit(1);
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putbyte(1 << 5);
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putbyte(0);
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#endif
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/* flush remaining bits */
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assert(k < CHAR_BIT);
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if (k > 0)
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{
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assert(b == MASKBITS(k));
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assert(op - bitp > 1);
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*bitp = LZO_BYTE(MASKBITS(k));
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DUMPBITS(k);
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assert(b == 0);
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assert(k == 0);
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}
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assert(c->textsize == in_len);
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c->codesize = op - out;
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*out_len = op - out;
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if (c->cb)
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(*c->cb)(c->textsize,c->codesize);
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#if 0
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printf("%ld -> %ld: %ld %ld %ld %ld %ld %ld\n",
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(long) c->textsize, (long) c->codesize,
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c->lit_bytes, c->m1, c->m2, c->m3, c->m4, c->lazy);
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#endif
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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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LZO_PUBLIC(int)
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lzo2a_999_compress ( const lzo_byte *in , lzo_uint in_len,
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lzo_byte *out, lzo_uintp out_len,
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lzo_voidp wrkmem )
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{
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return lzo2a_999_compress_callback(in,in_len,out,out_len,wrkmem,
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(lzo_progress_callback_t) 0, 0);
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}
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#endif /* !defined(LZO_999_UNSUPPORTED) */
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/*
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vi:ts=4:et
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*/
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//martysama0134's 2e58d0b8baeb072acdf3afc4a5d1999f
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