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921 lines
20 KiB
C
921 lines
20 KiB
C
/* lzo1x_9x.c -- implementation of the LZO1X-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) 2008 Markus Franz Xaver Johannes Oberhumer
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Copyright (C) 2007 Markus Franz Xaver Johannes Oberhumer
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Copyright (C) 2006 Markus Franz Xaver Johannes Oberhumer
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Copyright (C) 2005 Markus Franz Xaver Johannes Oberhumer
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Copyright (C) 2004 Markus Franz Xaver Johannes Oberhumer
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Copyright (C) 2003 Markus Franz Xaver Johannes Oberhumer
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Copyright (C) 2002 Markus Franz Xaver Johannes Oberhumer
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Copyright (C) 2001 Markus Franz Xaver Johannes Oberhumer
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Copyright (C) 2000 Markus Franz Xaver Johannes Oberhumer
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Copyright (C) 1999 Markus Franz Xaver Johannes Oberhumer
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Copyright (C) 1998 Markus Franz Xaver Johannes Oberhumer
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Copyright (C) 1997 Markus Franz Xaver Johannes Oberhumer
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Copyright (C) 1996 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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#include "libbb.h"
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/* The following is probably only safe on Intel-compatible processors ... */
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#define LZO_UNALIGNED_OK_2
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#define LZO_UNALIGNED_OK_4
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#include "liblzo.h"
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#define LZO_MAX(a,b) ((a) >= (b) ? (a) : (b))
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#define LZO_MIN(a,b) ((a) <= (b) ? (a) : (b))
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#define LZO_MAX3(a,b,c) ((a) >= (b) ? LZO_MAX(a,c) : LZO_MAX(b,c))
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/***********************************************************************
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//
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************************************************************************/
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#define SWD_N M4_MAX_OFFSET /* size of ring buffer */
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#define SWD_F 2048 /* upper limit for match length */
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#define SWD_BEST_OFF (LZO_MAX3(M2_MAX_LEN, M3_MAX_LEN, M4_MAX_LEN) + 1)
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typedef struct {
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int init;
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unsigned look; /* bytes in lookahead buffer */
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unsigned m_len;
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unsigned m_off;
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const uint8_t *bp;
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const uint8_t *ip;
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const uint8_t *in;
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const uint8_t *in_end;
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uint8_t *out;
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unsigned r1_lit;
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} lzo1x_999_t;
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#define getbyte(c) ((c).ip < (c).in_end ? *((c).ip)++ : (-1))
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/* lzo_swd.c -- sliding window dictionary */
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/***********************************************************************
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//
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************************************************************************/
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#define SWD_UINT_MAX USHRT_MAX
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#ifndef SWD_HSIZE
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# define SWD_HSIZE 16384
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#endif
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#ifndef SWD_MAX_CHAIN
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# define SWD_MAX_CHAIN 2048
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#endif
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#define HEAD3(b, p) \
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( ((0x9f5f * ((((b[p]<<5)^b[p+1])<<5) ^ b[p+2])) >> 5) & (SWD_HSIZE-1) )
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#if defined(LZO_UNALIGNED_OK_2)
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# define HEAD2(b,p) (* (bb__aliased_uint16_t *) &(b[p]))
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#else
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# define HEAD2(b,p) (b[p] ^ ((unsigned)b[p+1]<<8))
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#endif
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#define NIL2 SWD_UINT_MAX
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typedef struct lzo_swd {
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/* public - "built-in" */
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/* public - configuration */
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unsigned max_chain;
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int use_best_off;
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/* public - output */
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unsigned m_len;
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unsigned m_off;
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unsigned look;
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int b_char;
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#if defined(SWD_BEST_OFF)
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unsigned best_off[SWD_BEST_OFF];
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#endif
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/* semi public */
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lzo1x_999_t *c;
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unsigned m_pos;
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#if defined(SWD_BEST_OFF)
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unsigned best_pos[SWD_BEST_OFF];
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#endif
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/* private */
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unsigned ip; /* input pointer (lookahead) */
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unsigned bp; /* buffer pointer */
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unsigned rp; /* remove pointer */
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unsigned node_count;
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unsigned first_rp;
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uint8_t b[SWD_N + SWD_F];
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uint8_t b_wrap[SWD_F]; /* must follow b */
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uint16_t head3[SWD_HSIZE];
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uint16_t succ3[SWD_N + SWD_F];
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uint16_t best3[SWD_N + SWD_F];
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uint16_t llen3[SWD_HSIZE];
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#ifdef HEAD2
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uint16_t head2[65536L];
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#endif
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} lzo_swd_t, *lzo_swd_p;
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#define SIZEOF_LZO_SWD_T (sizeof(lzo_swd_t))
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/* Access macro for head3.
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* head3[key] may be uninitialized, but then its value will never be used.
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*/
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#define s_get_head3(s,key) s->head3[key]
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/***********************************************************************
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//
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************************************************************************/
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#define B_SIZE (SWD_N + SWD_F)
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static int swd_init(lzo_swd_p s)
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{
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/* defaults */
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s->node_count = SWD_N;
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memset(s->llen3, 0, sizeof(s->llen3[0]) * (unsigned)SWD_HSIZE);
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#ifdef HEAD2
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memset(s->head2, 0xff, sizeof(s->head2[0]) * 65536L);
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assert(s->head2[0] == NIL2);
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#endif
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s->ip = 0;
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s->bp = s->ip;
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s->first_rp = s->ip;
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assert(s->ip + SWD_F <= B_SIZE);
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s->look = (unsigned) (s->c->in_end - s->c->ip);
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if (s->look > 0) {
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if (s->look > SWD_F)
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s->look = SWD_F;
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memcpy(&s->b[s->ip], s->c->ip, s->look);
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s->c->ip += s->look;
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s->ip += s->look;
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}
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if (s->ip == B_SIZE)
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s->ip = 0;
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s->rp = s->first_rp;
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if (s->rp >= s->node_count)
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s->rp -= s->node_count;
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else
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s->rp += B_SIZE - s->node_count;
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return LZO_E_OK;
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}
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#define swd_pos2off(s,pos) \
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(s->bp > (pos) ? s->bp - (pos) : B_SIZE - ((pos) - s->bp))
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/***********************************************************************
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//
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************************************************************************/
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static void swd_getbyte(lzo_swd_p s)
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{
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int c;
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if ((c = getbyte(*(s->c))) < 0) {
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if (s->look > 0)
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--s->look;
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} else {
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s->b[s->ip] = c;
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if (s->ip < SWD_F)
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s->b_wrap[s->ip] = c;
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}
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if (++s->ip == B_SIZE)
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s->ip = 0;
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if (++s->bp == B_SIZE)
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s->bp = 0;
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if (++s->rp == B_SIZE)
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s->rp = 0;
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}
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/***********************************************************************
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// remove node from lists
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************************************************************************/
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static void swd_remove_node(lzo_swd_p s, unsigned node)
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{
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if (s->node_count == 0) {
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unsigned key;
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key = HEAD3(s->b,node);
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assert(s->llen3[key] > 0);
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--s->llen3[key];
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#ifdef HEAD2
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key = HEAD2(s->b,node);
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assert(s->head2[key] != NIL2);
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if ((unsigned) s->head2[key] == node)
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s->head2[key] = NIL2;
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#endif
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} else
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--s->node_count;
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}
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/***********************************************************************
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//
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************************************************************************/
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static void swd_accept(lzo_swd_p s, unsigned n)
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{
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assert(n <= s->look);
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while (n--) {
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unsigned key;
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swd_remove_node(s,s->rp);
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/* add bp into HEAD3 */
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key = HEAD3(s->b, s->bp);
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s->succ3[s->bp] = s_get_head3(s, key);
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s->head3[key] = s->bp;
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s->best3[s->bp] = SWD_F + 1;
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s->llen3[key]++;
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assert(s->llen3[key] <= SWD_N);
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#ifdef HEAD2
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/* add bp into HEAD2 */
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key = HEAD2(s->b, s->bp);
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s->head2[key] = s->bp;
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#endif
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swd_getbyte(s);
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}
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}
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/***********************************************************************
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//
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************************************************************************/
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static void swd_search(lzo_swd_p s, unsigned node, unsigned cnt)
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{
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const uint8_t *p1;
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const uint8_t *p2;
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const uint8_t *px;
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unsigned m_len = s->m_len;
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const uint8_t *b = s->b;
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const uint8_t *bp = s->b + s->bp;
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const uint8_t *bx = s->b + s->bp + s->look;
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unsigned char scan_end1;
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assert(s->m_len > 0);
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scan_end1 = bp[m_len - 1];
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for ( ; cnt-- > 0; node = s->succ3[node]) {
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p1 = bp;
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p2 = b + node;
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px = bx;
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assert(m_len < s->look);
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if (p2[m_len - 1] == scan_end1
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&& p2[m_len] == p1[m_len]
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&& p2[0] == p1[0]
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&& p2[1] == p1[1]
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) {
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unsigned i;
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assert(lzo_memcmp(bp, &b[node], 3) == 0);
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p1 += 2; p2 += 2;
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do {} while (++p1 < px && *p1 == *++p2);
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i = p1-bp;
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assert(lzo_memcmp(bp, &b[node], i) == 0);
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#if defined(SWD_BEST_OFF)
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if (i < SWD_BEST_OFF) {
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if (s->best_pos[i] == 0)
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s->best_pos[i] = node + 1;
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}
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#endif
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if (i > m_len) {
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s->m_len = m_len = i;
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s->m_pos = node;
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if (m_len == s->look)
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return;
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if (m_len >= SWD_F)
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return;
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if (m_len > (unsigned) s->best3[node])
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return;
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scan_end1 = bp[m_len - 1];
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}
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}
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}
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}
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/***********************************************************************
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//
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************************************************************************/
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#ifdef HEAD2
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static int swd_search2(lzo_swd_p s)
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{
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unsigned key;
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assert(s->look >= 2);
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assert(s->m_len > 0);
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key = s->head2[HEAD2(s->b, s->bp)];
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if (key == NIL2)
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return 0;
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assert(lzo_memcmp(&s->b[s->bp], &s->b[key], 2) == 0);
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#if defined(SWD_BEST_OFF)
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if (s->best_pos[2] == 0)
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s->best_pos[2] = key + 1;
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#endif
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if (s->m_len < 2) {
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s->m_len = 2;
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s->m_pos = key;
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}
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return 1;
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}
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#endif
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/***********************************************************************
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//
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************************************************************************/
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static void swd_findbest(lzo_swd_p s)
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{
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unsigned key;
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unsigned cnt, node;
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unsigned len;
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assert(s->m_len > 0);
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/* get current head, add bp into HEAD3 */
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key = HEAD3(s->b,s->bp);
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node = s->succ3[s->bp] = s_get_head3(s, key);
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cnt = s->llen3[key]++;
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assert(s->llen3[key] <= SWD_N + SWD_F);
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if (cnt > s->max_chain)
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cnt = s->max_chain;
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s->head3[key] = s->bp;
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s->b_char = s->b[s->bp];
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len = s->m_len;
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if (s->m_len >= s->look) {
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if (s->look == 0)
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s->b_char = -1;
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s->m_off = 0;
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s->best3[s->bp] = SWD_F + 1;
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} else {
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#ifdef HEAD2
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if (swd_search2(s))
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#endif
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if (s->look >= 3)
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swd_search(s, node, cnt);
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if (s->m_len > len)
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s->m_off = swd_pos2off(s,s->m_pos);
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s->best3[s->bp] = s->m_len;
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#if defined(SWD_BEST_OFF)
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if (s->use_best_off) {
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int i;
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for (i = 2; i < SWD_BEST_OFF; i++) {
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if (s->best_pos[i] > 0)
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s->best_off[i] = swd_pos2off(s, s->best_pos[i]-1);
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else
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s->best_off[i] = 0;
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}
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}
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#endif
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}
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swd_remove_node(s,s->rp);
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#ifdef HEAD2
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/* add bp into HEAD2 */
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key = HEAD2(s->b, s->bp);
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s->head2[key] = s->bp;
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#endif
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}
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#undef HEAD3
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#undef HEAD2
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#undef s_get_head3
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/***********************************************************************
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//
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************************************************************************/
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static int init_match(lzo1x_999_t *c, lzo_swd_p s, uint32_t use_best_off)
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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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r = swd_init(s);
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if (r != 0)
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return r;
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s->use_best_off = use_best_off;
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return r;
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}
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/***********************************************************************
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//
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************************************************************************/
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static int find_match(lzo1x_999_t *c, lzo_swd_p s,
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unsigned this_len, unsigned skip)
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{
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assert(c->init);
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if (skip > 0) {
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assert(this_len >= skip);
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swd_accept(s, this_len - skip);
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} else {
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assert(this_len <= 1);
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}
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s->m_len = 1;
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#ifdef SWD_BEST_OFF
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if (s->use_best_off)
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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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c->look = 0;
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c->m_len = 0;
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} else {
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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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return LZO_E_OK;
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}
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/* this is a public functions, but there is no prototype in a header file */
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static int lzo1x_999_compress_internal(const uint8_t *in , unsigned in_len,
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uint8_t *out, unsigned *out_len,
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void *wrkmem,
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unsigned good_length,
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unsigned max_lazy,
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unsigned max_chain,
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uint32_t use_best_off);
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/***********************************************************************
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//
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************************************************************************/
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static uint8_t *code_match(lzo1x_999_t *c,
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uint8_t *op, unsigned m_len, unsigned m_off)
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{
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assert(op > c->out);
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if (m_len == 2) {
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assert(m_off <= M1_MAX_OFFSET);
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assert(c->r1_lit > 0);
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assert(c->r1_lit < 4);
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m_off -= 1;
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*op++ = M1_MARKER | ((m_off & 3) << 2);
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*op++ = m_off >> 2;
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} else if (m_len <= M2_MAX_LEN && m_off <= M2_MAX_OFFSET) {
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assert(m_len >= 3);
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m_off -= 1;
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*op++ = ((m_len - 1) << 5) | ((m_off & 7) << 2);
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*op++ = m_off >> 3;
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assert(op[-2] >= M2_MARKER);
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} else if (m_len == M2_MIN_LEN && m_off <= MX_MAX_OFFSET && c->r1_lit >= 4) {
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assert(m_len == 3);
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assert(m_off > M2_MAX_OFFSET);
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m_off -= 1 + M2_MAX_OFFSET;
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*op++ = M1_MARKER | ((m_off & 3) << 2);
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*op++ = m_off >> 2;
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|
} else if (m_off <= M3_MAX_OFFSET) {
|
|
assert(m_len >= 3);
|
|
m_off -= 1;
|
|
if (m_len <= M3_MAX_LEN)
|
|
*op++ = M3_MARKER | (m_len - 2);
|
|
else {
|
|
m_len -= M3_MAX_LEN;
|
|
*op++ = M3_MARKER | 0;
|
|
while (m_len > 255) {
|
|
m_len -= 255;
|
|
*op++ = 0;
|
|
}
|
|
assert(m_len > 0);
|
|
*op++ = m_len;
|
|
}
|
|
*op++ = m_off << 2;
|
|
*op++ = m_off >> 6;
|
|
} else {
|
|
unsigned k;
|
|
|
|
assert(m_len >= 3);
|
|
assert(m_off > 0x4000);
|
|
assert(m_off <= 0xbfff);
|
|
m_off -= 0x4000;
|
|
k = (m_off & 0x4000) >> 11;
|
|
if (m_len <= M4_MAX_LEN)
|
|
*op++ = M4_MARKER | k | (m_len - 2);
|
|
else {
|
|
m_len -= M4_MAX_LEN;
|
|
*op++ = M4_MARKER | k | 0;
|
|
while (m_len > 255) {
|
|
m_len -= 255;
|
|
*op++ = 0;
|
|
}
|
|
assert(m_len > 0);
|
|
*op++ = m_len;
|
|
}
|
|
*op++ = m_off << 2;
|
|
*op++ = m_off >> 6;
|
|
}
|
|
|
|
return op;
|
|
}
|
|
|
|
|
|
static uint8_t *STORE_RUN(lzo1x_999_t *c, uint8_t *op,
|
|
const uint8_t *ii, unsigned t)
|
|
{
|
|
if (op == c->out && t <= 238) {
|
|
*op++ = 17 + t;
|
|
} else if (t <= 3) {
|
|
op[-2] |= t;
|
|
} else if (t <= 18) {
|
|
*op++ = t - 3;
|
|
} else {
|
|
unsigned tt = t - 18;
|
|
|
|
*op++ = 0;
|
|
while (tt > 255) {
|
|
tt -= 255;
|
|
*op++ = 0;
|
|
}
|
|
assert(tt > 0);
|
|
*op++ = tt;
|
|
}
|
|
do *op++ = *ii++; while (--t > 0);
|
|
|
|
return op;
|
|
}
|
|
|
|
|
|
static uint8_t *code_run(lzo1x_999_t *c, uint8_t *op, const uint8_t *ii,
|
|
unsigned lit)
|
|
{
|
|
if (lit > 0) {
|
|
assert(m_len >= 2);
|
|
op = STORE_RUN(c, op, ii, lit);
|
|
} else {
|
|
assert(m_len >= 3);
|
|
}
|
|
c->r1_lit = lit;
|
|
|
|
return op;
|
|
}
|
|
|
|
|
|
/***********************************************************************
|
|
//
|
|
************************************************************************/
|
|
static int len_of_coded_match(unsigned m_len, unsigned m_off, unsigned lit)
|
|
{
|
|
int n = 4;
|
|
|
|
if (m_len < 2)
|
|
return -1;
|
|
if (m_len == 2)
|
|
return (m_off <= M1_MAX_OFFSET && lit > 0 && lit < 4) ? 2 : -1;
|
|
if (m_len <= M2_MAX_LEN && m_off <= M2_MAX_OFFSET)
|
|
return 2;
|
|
if (m_len == M2_MIN_LEN && m_off <= MX_MAX_OFFSET && lit >= 4)
|
|
return 2;
|
|
if (m_off <= M3_MAX_OFFSET) {
|
|
if (m_len <= M3_MAX_LEN)
|
|
return 3;
|
|
m_len -= M3_MAX_LEN;
|
|
} else if (m_off <= M4_MAX_OFFSET) {
|
|
if (m_len <= M4_MAX_LEN)
|
|
return 3;
|
|
m_len -= M4_MAX_LEN;
|
|
} else
|
|
return -1;
|
|
while (m_len > 255) {
|
|
m_len -= 255;
|
|
n++;
|
|
}
|
|
return n;
|
|
}
|
|
|
|
|
|
static int min_gain(unsigned ahead, unsigned lit1,
|
|
unsigned lit2, int l1, int l2, int l3)
|
|
{
|
|
int lazy_match_min_gain = 0;
|
|
|
|
assert (ahead >= 1);
|
|
lazy_match_min_gain += ahead;
|
|
|
|
if (lit1 <= 3)
|
|
lazy_match_min_gain += (lit2 <= 3) ? 0 : 2;
|
|
else if (lit1 <= 18)
|
|
lazy_match_min_gain += (lit2 <= 18) ? 0 : 1;
|
|
|
|
lazy_match_min_gain += (l2 - l1) * 2;
|
|
if (l3 > 0)
|
|
lazy_match_min_gain -= (ahead - l3) * 2;
|
|
|
|
if (lazy_match_min_gain < 0)
|
|
lazy_match_min_gain = 0;
|
|
|
|
return lazy_match_min_gain;
|
|
}
|
|
|
|
|
|
/***********************************************************************
|
|
//
|
|
************************************************************************/
|
|
#if defined(SWD_BEST_OFF)
|
|
|
|
static void better_match(const lzo_swd_p swd,
|
|
unsigned *m_len, unsigned *m_off)
|
|
{
|
|
if (*m_len <= M2_MIN_LEN)
|
|
return;
|
|
|
|
if (*m_off <= M2_MAX_OFFSET)
|
|
return;
|
|
|
|
/* M3/M4 -> M2 */
|
|
if (*m_off > M2_MAX_OFFSET
|
|
&& *m_len >= M2_MIN_LEN + 1 && *m_len <= M2_MAX_LEN + 1
|
|
&& swd->best_off[*m_len-1] && swd->best_off[*m_len-1] <= M2_MAX_OFFSET
|
|
) {
|
|
*m_len = *m_len - 1;
|
|
*m_off = swd->best_off[*m_len];
|
|
return;
|
|
}
|
|
|
|
/* M4 -> M2 */
|
|
if (*m_off > M3_MAX_OFFSET
|
|
&& *m_len >= M4_MAX_LEN + 1 && *m_len <= M2_MAX_LEN + 2
|
|
&& swd->best_off[*m_len-2] && swd->best_off[*m_len-2] <= M2_MAX_OFFSET
|
|
) {
|
|
*m_len = *m_len - 2;
|
|
*m_off = swd->best_off[*m_len];
|
|
return;
|
|
}
|
|
/* M4 -> M3 */
|
|
if (*m_off > M3_MAX_OFFSET
|
|
&& *m_len >= M4_MAX_LEN + 1 && *m_len <= M3_MAX_LEN + 1
|
|
&& swd->best_off[*m_len-1] && swd->best_off[*m_len-1] <= M3_MAX_OFFSET
|
|
) {
|
|
*m_len = *m_len - 1;
|
|
*m_off = swd->best_off[*m_len];
|
|
}
|
|
}
|
|
|
|
#endif
|
|
|
|
|
|
/***********************************************************************
|
|
//
|
|
************************************************************************/
|
|
static int lzo1x_999_compress_internal(const uint8_t *in, unsigned in_len,
|
|
uint8_t *out, unsigned *out_len,
|
|
void *wrkmem,
|
|
unsigned good_length,
|
|
unsigned max_lazy,
|
|
unsigned max_chain,
|
|
uint32_t use_best_off)
|
|
{
|
|
uint8_t *op;
|
|
const uint8_t *ii;
|
|
unsigned lit;
|
|
unsigned m_len, m_off;
|
|
lzo1x_999_t cc;
|
|
lzo1x_999_t *const c = &cc;
|
|
const lzo_swd_p swd = (lzo_swd_p) wrkmem;
|
|
int r;
|
|
|
|
c->init = 0;
|
|
c->ip = c->in = in;
|
|
c->in_end = in + in_len;
|
|
c->out = out;
|
|
|
|
op = out;
|
|
ii = c->ip; /* point to start of literal run */
|
|
lit = 0;
|
|
c->r1_lit = 0;
|
|
|
|
r = init_match(c, swd, use_best_off);
|
|
if (r != 0)
|
|
return r;
|
|
swd->max_chain = max_chain;
|
|
|
|
r = find_match(c, swd, 0, 0);
|
|
if (r != 0)
|
|
return r;
|
|
|
|
while (c->look > 0) {
|
|
unsigned ahead;
|
|
unsigned max_ahead;
|
|
int l1, l2, l3;
|
|
|
|
m_len = c->m_len;
|
|
m_off = c->m_off;
|
|
|
|
assert(c->bp == c->ip - c->look);
|
|
assert(c->bp >= in);
|
|
if (lit == 0)
|
|
ii = c->bp;
|
|
assert(ii + lit == c->bp);
|
|
assert(swd->b_char == *(c->bp));
|
|
|
|
if (m_len < 2
|
|
|| (m_len == 2 && (m_off > M1_MAX_OFFSET || lit == 0 || lit >= 4))
|
|
/* Do not accept this match for compressed-data compatibility
|
|
* with LZO v1.01 and before
|
|
* [ might be a problem for decompress() and optimize() ]
|
|
*/
|
|
|| (m_len == 2 && op == out)
|
|
|| (op == out && lit == 0)
|
|
) {
|
|
/* a literal */
|
|
m_len = 0;
|
|
}
|
|
else if (m_len == M2_MIN_LEN) {
|
|
/* compression ratio improves if we code a literal in some cases */
|
|
if (m_off > MX_MAX_OFFSET && lit >= 4)
|
|
m_len = 0;
|
|
}
|
|
|
|
if (m_len == 0) {
|
|
/* a literal */
|
|
lit++;
|
|
swd->max_chain = max_chain;
|
|
r = find_match(c, swd, 1, 0);
|
|
assert(r == 0);
|
|
continue;
|
|
}
|
|
|
|
/* a match */
|
|
#if defined(SWD_BEST_OFF)
|
|
if (swd->use_best_off)
|
|
better_match(swd, &m_len, &m_off);
|
|
#endif
|
|
|
|
/* shall we try a lazy match ? */
|
|
ahead = 0;
|
|
if (m_len >= max_lazy) {
|
|
/* no */
|
|
l1 = 0;
|
|
max_ahead = 0;
|
|
} else {
|
|
/* yes, try a lazy match */
|
|
l1 = len_of_coded_match(m_len, m_off, lit);
|
|
assert(l1 > 0);
|
|
max_ahead = LZO_MIN(2, (unsigned)l1 - 1);
|
|
}
|
|
|
|
|
|
while (ahead < max_ahead && c->look > m_len) {
|
|
int lazy_match_min_gain;
|
|
|
|
if (m_len >= good_length)
|
|
swd->max_chain = max_chain >> 2;
|
|
else
|
|
swd->max_chain = max_chain;
|
|
r = find_match(c, swd, 1, 0);
|
|
ahead++;
|
|
|
|
assert(r == 0);
|
|
assert(c->look > 0);
|
|
assert(ii + lit + ahead == c->bp);
|
|
|
|
if (c->m_len < m_len)
|
|
continue;
|
|
if (c->m_len == m_len && c->m_off >= m_off)
|
|
continue;
|
|
#if defined(SWD_BEST_OFF)
|
|
if (swd->use_best_off)
|
|
better_match(swd, &c->m_len, &c->m_off);
|
|
#endif
|
|
l2 = len_of_coded_match(c->m_len, c->m_off, lit+ahead);
|
|
if (l2 < 0)
|
|
continue;
|
|
|
|
/* compressed-data compatibility [see above] */
|
|
l3 = (op == out) ? -1 : len_of_coded_match(ahead, m_off, lit);
|
|
|
|
lazy_match_min_gain = min_gain(ahead, lit, lit+ahead, l1, l2, l3);
|
|
if (c->m_len >= m_len + lazy_match_min_gain) {
|
|
if (l3 > 0) {
|
|
/* code previous run */
|
|
op = code_run(c, op, ii, lit);
|
|
lit = 0;
|
|
/* code shortened match */
|
|
op = code_match(c, op, ahead, m_off);
|
|
} else {
|
|
lit += ahead;
|
|
assert(ii + lit == c->bp);
|
|
}
|
|
goto lazy_match_done;
|
|
}
|
|
}
|
|
|
|
assert(ii + lit + ahead == c->bp);
|
|
|
|
/* 1 - code run */
|
|
op = code_run(c, op, ii, lit);
|
|
lit = 0;
|
|
|
|
/* 2 - code match */
|
|
op = code_match(c, op, m_len, m_off);
|
|
swd->max_chain = max_chain;
|
|
r = find_match(c, swd, m_len, 1+ahead);
|
|
assert(r == 0);
|
|
|
|
lazy_match_done: ;
|
|
}
|
|
|
|
/* store final run */
|
|
if (lit > 0)
|
|
op = STORE_RUN(c, op, ii, lit);
|
|
|
|
#if defined(LZO_EOF_CODE)
|
|
*op++ = M4_MARKER | 1;
|
|
*op++ = 0;
|
|
*op++ = 0;
|
|
#endif
|
|
|
|
*out_len = op - out;
|
|
|
|
return LZO_E_OK;
|
|
}
|
|
|
|
|
|
/***********************************************************************
|
|
//
|
|
************************************************************************/
|
|
int lzo1x_999_compress_level(const uint8_t *in, unsigned in_len,
|
|
uint8_t *out, unsigned *out_len,
|
|
void *wrkmem,
|
|
int compression_level)
|
|
{
|
|
static const struct {
|
|
uint16_t good_length;
|
|
uint16_t max_lazy;
|
|
uint16_t max_chain;
|
|
uint16_t use_best_off;
|
|
} c[3] = {
|
|
{ 8, 32, 256, 0 },
|
|
{ 32, 128, 2048, 1 },
|
|
{ SWD_F, SWD_F, 4096, 1 } /* max. compression */
|
|
};
|
|
|
|
if (compression_level < 7 || compression_level > 9)
|
|
return LZO_E_ERROR;
|
|
|
|
compression_level -= 7;
|
|
return lzo1x_999_compress_internal(in, in_len, out, out_len, wrkmem,
|
|
c[compression_level].good_length,
|
|
c[compression_level].max_lazy,
|
|
c[compression_level].max_chain,
|
|
c[compression_level].use_best_off);
|
|
}
|