[3320] | 1 | /* lzo1x_9x.c -- implementation of the LZO1X-999 compression algorithm
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| 2 |
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| 3 | This file is part of the LZO real-time data compression library.
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| 4 |
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| 5 | Copyright (C) 2008 Markus Franz Xaver Johannes Oberhumer
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| 6 | Copyright (C) 2007 Markus Franz Xaver Johannes Oberhumer
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| 7 | Copyright (C) 2006 Markus Franz Xaver Johannes Oberhumer
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| 8 | Copyright (C) 2005 Markus Franz Xaver Johannes Oberhumer
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| 9 | Copyright (C) 2004 Markus Franz Xaver Johannes Oberhumer
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| 10 | Copyright (C) 2003 Markus Franz Xaver Johannes Oberhumer
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| 11 | Copyright (C) 2002 Markus Franz Xaver Johannes Oberhumer
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| 12 | Copyright (C) 2001 Markus Franz Xaver Johannes Oberhumer
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| 13 | Copyright (C) 2000 Markus Franz Xaver Johannes Oberhumer
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| 14 | Copyright (C) 1999 Markus Franz Xaver Johannes Oberhumer
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| 15 | Copyright (C) 1998 Markus Franz Xaver Johannes Oberhumer
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| 16 | Copyright (C) 1997 Markus Franz Xaver Johannes Oberhumer
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| 17 | Copyright (C) 1996 Markus Franz Xaver Johannes Oberhumer
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| 18 | All Rights Reserved.
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| 19 |
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| 20 | The LZO library is free software; you can redistribute it and/or
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| 21 | modify it under the terms of the GNU General Public License as
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| 22 | published by the Free Software Foundation; either version 2 of
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| 23 | the License, or (at your option) any later version.
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| 24 |
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| 25 | The LZO library is distributed in the hope that it will be useful,
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| 26 | but WITHOUT ANY WARRANTY; without even the implied warranty of
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| 27 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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| 28 | GNU General Public License for more details.
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| 29 |
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| 30 | You should have received a copy of the GNU General Public License
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| 31 | along with the LZO library; see the file COPYING.
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| 32 | If not, write to the Free Software Foundation, Inc.,
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| 33 | 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
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| 34 |
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| 35 | Markus F.X.J. Oberhumer
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| 36 | <markus@oberhumer.com>
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| 37 | http://www.oberhumer.com/opensource/lzo/
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| 38 | */
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| 39 | #include "libbb.h"
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| 40 |
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| 41 | /* The following is probably only safe on Intel-compatible processors ... */
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| 42 | #define LZO_UNALIGNED_OK_2
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| 43 | #define LZO_UNALIGNED_OK_4
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| 44 |
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| 45 | #include "liblzo.h"
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| 46 |
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| 47 | #define LZO_MAX(a,b) ((a) >= (b) ? (a) : (b))
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| 48 | #define LZO_MIN(a,b) ((a) <= (b) ? (a) : (b))
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| 49 | #define LZO_MAX3(a,b,c) ((a) >= (b) ? LZO_MAX(a,c) : LZO_MAX(b,c))
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| 50 |
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| 51 | /***********************************************************************
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| 52 | //
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| 53 | ************************************************************************/
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| 54 | #define SWD_N M4_MAX_OFFSET /* size of ring buffer */
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| 55 | #define SWD_F 2048 /* upper limit for match length */
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| 56 |
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| 57 | #define SWD_BEST_OFF (LZO_MAX3(M2_MAX_LEN, M3_MAX_LEN, M4_MAX_LEN) + 1)
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| 58 |
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| 59 | typedef struct {
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| 60 | int init;
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| 61 |
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| 62 | unsigned look; /* bytes in lookahead buffer */
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| 63 |
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| 64 | unsigned m_len;
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| 65 | unsigned m_off;
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| 66 |
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| 67 | const uint8_t *bp;
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| 68 | const uint8_t *ip;
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| 69 | const uint8_t *in;
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| 70 | const uint8_t *in_end;
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| 71 | uint8_t *out;
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| 72 |
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| 73 | unsigned r1_lit;
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| 74 |
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| 75 | } lzo1x_999_t;
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| 76 |
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| 77 | #define getbyte(c) ((c).ip < (c).in_end ? *((c).ip)++ : (-1))
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| 78 |
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| 79 | /* lzo_swd.c -- sliding window dictionary */
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| 80 |
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| 81 | /***********************************************************************
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| 82 | //
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| 83 | ************************************************************************/
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| 84 | #define SWD_UINT_MAX USHRT_MAX
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| 85 |
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| 86 | #ifndef SWD_HSIZE
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| 87 | # define SWD_HSIZE 16384
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| 88 | #endif
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| 89 | #ifndef SWD_MAX_CHAIN
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| 90 | # define SWD_MAX_CHAIN 2048
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| 91 | #endif
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| 92 |
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| 93 | #define HEAD3(b, p) \
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| 94 | ( ((0x9f5f * ((((b[p]<<5)^b[p+1])<<5) ^ b[p+2])) >> 5) & (SWD_HSIZE-1) )
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| 95 |
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| 96 | #if defined(LZO_UNALIGNED_OK_2)
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| 97 | # define HEAD2(b,p) (* (uint16_t *) &(b[p]))
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| 98 | #else
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| 99 | # define HEAD2(b,p) (b[p] ^ ((unsigned)b[p+1]<<8))
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| 100 | #endif
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| 101 | #define NIL2 SWD_UINT_MAX
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| 102 |
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| 103 | typedef struct lzo_swd {
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| 104 | /* public - "built-in" */
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| 105 |
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| 106 | /* public - configuration */
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| 107 | unsigned max_chain;
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| 108 | int use_best_off;
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| 109 |
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| 110 | /* public - output */
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| 111 | unsigned m_len;
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| 112 | unsigned m_off;
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| 113 | unsigned look;
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| 114 | int b_char;
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| 115 | #if defined(SWD_BEST_OFF)
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| 116 | unsigned best_off[SWD_BEST_OFF];
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| 117 | #endif
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| 118 |
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| 119 | /* semi public */
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| 120 | lzo1x_999_t *c;
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| 121 | unsigned m_pos;
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| 122 | #if defined(SWD_BEST_OFF)
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| 123 | unsigned best_pos[SWD_BEST_OFF];
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| 124 | #endif
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| 125 |
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| 126 | /* private */
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| 127 | unsigned ip; /* input pointer (lookahead) */
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| 128 | unsigned bp; /* buffer pointer */
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| 129 | unsigned rp; /* remove pointer */
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| 130 |
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| 131 | unsigned node_count;
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| 132 | unsigned first_rp;
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| 133 |
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| 134 | uint8_t b[SWD_N + SWD_F];
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| 135 | uint8_t b_wrap[SWD_F]; /* must follow b */
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| 136 | uint16_t head3[SWD_HSIZE];
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| 137 | uint16_t succ3[SWD_N + SWD_F];
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| 138 | uint16_t best3[SWD_N + SWD_F];
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| 139 | uint16_t llen3[SWD_HSIZE];
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| 140 | #ifdef HEAD2
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| 141 | uint16_t head2[65536L];
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| 142 | #endif
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| 143 | } lzo_swd_t, *lzo_swd_p;
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| 144 |
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| 145 | #define SIZEOF_LZO_SWD_T (sizeof(lzo_swd_t))
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| 146 |
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| 147 |
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| 148 | /* Access macro for head3.
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| 149 | * head3[key] may be uninitialized, but then its value will never be used.
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| 150 | */
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| 151 | #define s_get_head3(s,key) s->head3[key]
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| 152 |
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| 153 |
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| 154 | /***********************************************************************
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| 155 | //
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| 156 | ************************************************************************/
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| 157 | #define B_SIZE (SWD_N + SWD_F)
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| 158 |
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| 159 | static int swd_init(lzo_swd_p s)
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| 160 | {
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| 161 | /* defaults */
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| 162 | s->node_count = SWD_N;
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| 163 |
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| 164 | memset(s->llen3, 0, sizeof(s->llen3[0]) * (unsigned)SWD_HSIZE);
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| 165 | #ifdef HEAD2
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| 166 | memset(s->head2, 0xff, sizeof(s->head2[0]) * 65536L);
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| 167 | assert(s->head2[0] == NIL2);
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| 168 | #endif
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| 169 |
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| 170 | s->ip = 0;
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| 171 | s->bp = s->ip;
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| 172 | s->first_rp = s->ip;
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| 173 |
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| 174 | assert(s->ip + SWD_F <= B_SIZE);
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| 175 | s->look = (unsigned) (s->c->in_end - s->c->ip);
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| 176 | if (s->look > 0) {
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| 177 | if (s->look > SWD_F)
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| 178 | s->look = SWD_F;
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| 179 | memcpy(&s->b[s->ip], s->c->ip, s->look);
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| 180 | s->c->ip += s->look;
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| 181 | s->ip += s->look;
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| 182 | }
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| 183 | if (s->ip == B_SIZE)
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| 184 | s->ip = 0;
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| 185 |
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| 186 | s->rp = s->first_rp;
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| 187 | if (s->rp >= s->node_count)
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| 188 | s->rp -= s->node_count;
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| 189 | else
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| 190 | s->rp += B_SIZE - s->node_count;
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| 191 |
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| 192 | return LZO_E_OK;
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| 193 | }
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| 194 |
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| 195 | #define swd_pos2off(s,pos) \
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| 196 | (s->bp > (pos) ? s->bp - (pos) : B_SIZE - ((pos) - s->bp))
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| 197 |
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| 198 |
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| 199 | /***********************************************************************
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| 200 | //
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| 201 | ************************************************************************/
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| 202 | static void swd_getbyte(lzo_swd_p s)
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| 203 | {
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| 204 | int c;
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| 205 |
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| 206 | if ((c = getbyte(*(s->c))) < 0) {
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| 207 | if (s->look > 0)
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| 208 | --s->look;
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| 209 | } else {
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| 210 | s->b[s->ip] = c;
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| 211 | if (s->ip < SWD_F)
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| 212 | s->b_wrap[s->ip] = c;
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| 213 | }
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| 214 | if (++s->ip == B_SIZE)
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| 215 | s->ip = 0;
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| 216 | if (++s->bp == B_SIZE)
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| 217 | s->bp = 0;
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| 218 | if (++s->rp == B_SIZE)
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| 219 | s->rp = 0;
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| 220 | }
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| 221 |
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| 222 |
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| 223 | /***********************************************************************
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| 224 | // remove node from lists
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| 225 | ************************************************************************/
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| 226 | static void swd_remove_node(lzo_swd_p s, unsigned node)
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| 227 | {
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| 228 | if (s->node_count == 0) {
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| 229 | unsigned key;
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| 230 |
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| 231 | key = HEAD3(s->b,node);
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| 232 | assert(s->llen3[key] > 0);
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| 233 | --s->llen3[key];
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| 234 |
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| 235 | #ifdef HEAD2
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| 236 | key = HEAD2(s->b,node);
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| 237 | assert(s->head2[key] != NIL2);
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| 238 | if ((unsigned) s->head2[key] == node)
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| 239 | s->head2[key] = NIL2;
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| 240 | #endif
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| 241 | } else
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| 242 | --s->node_count;
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| 243 | }
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| 244 |
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| 245 |
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| 246 | /***********************************************************************
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| 247 | //
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| 248 | ************************************************************************/
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| 249 | static void swd_accept(lzo_swd_p s, unsigned n)
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| 250 | {
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| 251 | assert(n <= s->look);
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| 252 |
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| 253 | while (n--) {
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| 254 | unsigned key;
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| 255 |
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| 256 | swd_remove_node(s,s->rp);
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| 257 |
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| 258 | /* add bp into HEAD3 */
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| 259 | key = HEAD3(s->b, s->bp);
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| 260 | s->succ3[s->bp] = s_get_head3(s, key);
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| 261 | s->head3[key] = s->bp;
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| 262 | s->best3[s->bp] = SWD_F + 1;
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| 263 | s->llen3[key]++;
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| 264 | assert(s->llen3[key] <= SWD_N);
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| 265 |
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| 266 | #ifdef HEAD2
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| 267 | /* add bp into HEAD2 */
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| 268 | key = HEAD2(s->b, s->bp);
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| 269 | s->head2[key] = s->bp;
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| 270 | #endif
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| 271 |
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| 272 | swd_getbyte(s);
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| 273 | }
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| 274 | }
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| 275 |
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| 276 |
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| 277 | /***********************************************************************
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| 278 | //
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| 279 | ************************************************************************/
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| 280 | static void swd_search(lzo_swd_p s, unsigned node, unsigned cnt)
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| 281 | {
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| 282 | const uint8_t *p1;
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| 283 | const uint8_t *p2;
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| 284 | const uint8_t *px;
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| 285 | unsigned m_len = s->m_len;
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| 286 | const uint8_t *b = s->b;
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| 287 | const uint8_t *bp = s->b + s->bp;
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| 288 | const uint8_t *bx = s->b + s->bp + s->look;
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| 289 | unsigned char scan_end1;
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| 290 |
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| 291 | assert(s->m_len > 0);
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| 292 |
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| 293 | scan_end1 = bp[m_len - 1];
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| 294 | for ( ; cnt-- > 0; node = s->succ3[node]) {
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| 295 | p1 = bp;
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| 296 | p2 = b + node;
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| 297 | px = bx;
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| 298 |
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| 299 | assert(m_len < s->look);
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| 300 |
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| 301 | if (p2[m_len - 1] == scan_end1
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| 302 | && p2[m_len] == p1[m_len]
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| 303 | && p2[0] == p1[0]
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| 304 | && p2[1] == p1[1]
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| 305 | ) {
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| 306 | unsigned i;
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| 307 | assert(lzo_memcmp(bp, &b[node], 3) == 0);
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| 308 |
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| 309 | p1 += 2; p2 += 2;
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| 310 | do {} while (++p1 < px && *p1 == *++p2);
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| 311 | i = p1-bp;
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| 312 |
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| 313 | assert(lzo_memcmp(bp, &b[node], i) == 0);
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| 314 |
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| 315 | #if defined(SWD_BEST_OFF)
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| 316 | if (i < SWD_BEST_OFF) {
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| 317 | if (s->best_pos[i] == 0)
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| 318 | s->best_pos[i] = node + 1;
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| 319 | }
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| 320 | #endif
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| 321 | if (i > m_len) {
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| 322 | s->m_len = m_len = i;
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| 323 | s->m_pos = node;
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| 324 | if (m_len == s->look)
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| 325 | return;
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| 326 | if (m_len >= SWD_F)
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| 327 | return;
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| 328 | if (m_len > (unsigned) s->best3[node])
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| 329 | return;
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| 330 | scan_end1 = bp[m_len - 1];
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| 331 | }
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| 332 | }
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| 333 | }
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| 334 | }
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| 335 |
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| 336 |
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| 337 | /***********************************************************************
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| 338 | //
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| 339 | ************************************************************************/
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| 340 | #ifdef HEAD2
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| 341 |
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| 342 | static int swd_search2(lzo_swd_p s)
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| 343 | {
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| 344 | unsigned key;
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| 345 |
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| 346 | assert(s->look >= 2);
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| 347 | assert(s->m_len > 0);
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| 348 |
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| 349 | key = s->head2[HEAD2(s->b, s->bp)];
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| 350 | if (key == NIL2)
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| 351 | return 0;
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| 352 | assert(lzo_memcmp(&s->b[s->bp], &s->b[key], 2) == 0);
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| 353 | #if defined(SWD_BEST_OFF)
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| 354 | if (s->best_pos[2] == 0)
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| 355 | s->best_pos[2] = key + 1;
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| 356 | #endif
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| 357 |
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| 358 | if (s->m_len < 2) {
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| 359 | s->m_len = 2;
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| 360 | s->m_pos = key;
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| 361 | }
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| 362 | return 1;
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| 363 | }
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| 364 |
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| 365 | #endif
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| 366 |
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| 367 |
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| 368 | /***********************************************************************
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| 369 | //
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| 370 | ************************************************************************/
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| 371 | static void swd_findbest(lzo_swd_p s)
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| 372 | {
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| 373 | unsigned key;
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| 374 | unsigned cnt, node;
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| 375 | unsigned len;
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| 376 |
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| 377 | assert(s->m_len > 0);
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| 378 |
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| 379 | /* get current head, add bp into HEAD3 */
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| 380 | key = HEAD3(s->b,s->bp);
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| 381 | node = s->succ3[s->bp] = s_get_head3(s, key);
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| 382 | cnt = s->llen3[key]++;
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| 383 | assert(s->llen3[key] <= SWD_N + SWD_F);
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| 384 | if (cnt > s->max_chain)
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| 385 | cnt = s->max_chain;
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| 386 | s->head3[key] = s->bp;
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| 387 |
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| 388 | s->b_char = s->b[s->bp];
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| 389 | len = s->m_len;
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| 390 | if (s->m_len >= s->look) {
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| 391 | if (s->look == 0)
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| 392 | s->b_char = -1;
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| 393 | s->m_off = 0;
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| 394 | s->best3[s->bp] = SWD_F + 1;
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| 395 | } else {
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| 396 | #ifdef HEAD2
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| 397 | if (swd_search2(s))
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| 398 | #endif
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| 399 | if (s->look >= 3)
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| 400 | swd_search(s, node, cnt);
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| 401 | if (s->m_len > len)
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| 402 | s->m_off = swd_pos2off(s,s->m_pos);
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| 403 | s->best3[s->bp] = s->m_len;
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| 404 |
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| 405 | #if defined(SWD_BEST_OFF)
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| 406 | if (s->use_best_off) {
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| 407 | int i;
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| 408 | for (i = 2; i < SWD_BEST_OFF; i++) {
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| 409 | if (s->best_pos[i] > 0)
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| 410 | s->best_off[i] = swd_pos2off(s, s->best_pos[i]-1);
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| 411 | else
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| 412 | s->best_off[i] = 0;
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| 413 | }
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| 414 | }
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| 415 | #endif
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| 416 | }
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| 417 |
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| 418 | swd_remove_node(s,s->rp);
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| 419 |
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| 420 | #ifdef HEAD2
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| 421 | /* add bp into HEAD2 */
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| 422 | key = HEAD2(s->b, s->bp);
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| 423 | s->head2[key] = s->bp;
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| 424 | #endif
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| 425 | }
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| 426 |
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| 427 | #undef HEAD3
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| 428 | #undef HEAD2
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| 429 | #undef s_get_head3
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| 430 |
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| 431 |
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| 432 | /***********************************************************************
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| 433 | //
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| 434 | ************************************************************************/
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| 435 | static int init_match(lzo1x_999_t *c, lzo_swd_p s, uint32_t use_best_off)
|
---|
| 436 | {
|
---|
| 437 | int r;
|
---|
| 438 |
|
---|
| 439 | assert(!c->init);
|
---|
| 440 | c->init = 1;
|
---|
| 441 |
|
---|
| 442 | s->c = c;
|
---|
| 443 |
|
---|
| 444 | r = swd_init(s);
|
---|
| 445 | if (r != 0)
|
---|
| 446 | return r;
|
---|
| 447 |
|
---|
| 448 | s->use_best_off = use_best_off;
|
---|
| 449 | return r;
|
---|
| 450 | }
|
---|
| 451 |
|
---|
| 452 |
|
---|
| 453 | /***********************************************************************
|
---|
| 454 | //
|
---|
| 455 | ************************************************************************/
|
---|
| 456 | static int find_match(lzo1x_999_t *c, lzo_swd_p s,
|
---|
| 457 | unsigned this_len, unsigned skip)
|
---|
| 458 | {
|
---|
| 459 | assert(c->init);
|
---|
| 460 |
|
---|
| 461 | if (skip > 0) {
|
---|
| 462 | assert(this_len >= skip);
|
---|
| 463 | swd_accept(s, this_len - skip);
|
---|
| 464 | } else {
|
---|
| 465 | assert(this_len <= 1);
|
---|
| 466 | }
|
---|
| 467 |
|
---|
| 468 | s->m_len = 1;
|
---|
| 469 | s->m_len = 1;
|
---|
| 470 | #ifdef SWD_BEST_OFF
|
---|
| 471 | if (s->use_best_off)
|
---|
| 472 | memset(s->best_pos, 0, sizeof(s->best_pos));
|
---|
| 473 | #endif
|
---|
| 474 | swd_findbest(s);
|
---|
| 475 | c->m_len = s->m_len;
|
---|
| 476 | c->m_off = s->m_off;
|
---|
| 477 |
|
---|
| 478 | swd_getbyte(s);
|
---|
| 479 |
|
---|
| 480 | if (s->b_char < 0) {
|
---|
| 481 | c->look = 0;
|
---|
| 482 | c->m_len = 0;
|
---|
| 483 | } else {
|
---|
| 484 | c->look = s->look + 1;
|
---|
| 485 | }
|
---|
| 486 | c->bp = c->ip - c->look;
|
---|
| 487 |
|
---|
| 488 | return LZO_E_OK;
|
---|
| 489 | }
|
---|
| 490 |
|
---|
| 491 | /* this is a public functions, but there is no prototype in a header file */
|
---|
| 492 | static int lzo1x_999_compress_internal(const uint8_t *in , unsigned in_len,
|
---|
| 493 | uint8_t *out, unsigned *out_len,
|
---|
| 494 | void *wrkmem,
|
---|
| 495 | unsigned good_length,
|
---|
| 496 | unsigned max_lazy,
|
---|
| 497 | unsigned max_chain,
|
---|
| 498 | uint32_t use_best_off);
|
---|
| 499 |
|
---|
| 500 |
|
---|
| 501 | /***********************************************************************
|
---|
| 502 | //
|
---|
| 503 | ************************************************************************/
|
---|
| 504 | static uint8_t *code_match(lzo1x_999_t *c,
|
---|
| 505 | uint8_t *op, unsigned m_len, unsigned m_off)
|
---|
| 506 | {
|
---|
| 507 | assert(op > c->out);
|
---|
| 508 | if (m_len == 2) {
|
---|
| 509 | assert(m_off <= M1_MAX_OFFSET);
|
---|
| 510 | assert(c->r1_lit > 0);
|
---|
| 511 | assert(c->r1_lit < 4);
|
---|
| 512 | m_off -= 1;
|
---|
| 513 | *op++ = M1_MARKER | ((m_off & 3) << 2);
|
---|
| 514 | *op++ = m_off >> 2;
|
---|
| 515 | } else if (m_len <= M2_MAX_LEN && m_off <= M2_MAX_OFFSET) {
|
---|
| 516 | assert(m_len >= 3);
|
---|
| 517 | m_off -= 1;
|
---|
| 518 | *op++ = ((m_len - 1) << 5) | ((m_off & 7) << 2);
|
---|
| 519 | *op++ = m_off >> 3;
|
---|
| 520 | assert(op[-2] >= M2_MARKER);
|
---|
| 521 | } else if (m_len == M2_MIN_LEN && m_off <= MX_MAX_OFFSET && c->r1_lit >= 4) {
|
---|
| 522 | assert(m_len == 3);
|
---|
| 523 | assert(m_off > M2_MAX_OFFSET);
|
---|
| 524 | m_off -= 1 + M2_MAX_OFFSET;
|
---|
| 525 | *op++ = M1_MARKER | ((m_off & 3) << 2);
|
---|
| 526 | *op++ = m_off >> 2;
|
---|
| 527 | } else if (m_off <= M3_MAX_OFFSET) {
|
---|
| 528 | assert(m_len >= 3);
|
---|
| 529 | m_off -= 1;
|
---|
| 530 | if (m_len <= M3_MAX_LEN)
|
---|
| 531 | *op++ = M3_MARKER | (m_len - 2);
|
---|
| 532 | else {
|
---|
| 533 | m_len -= M3_MAX_LEN;
|
---|
| 534 | *op++ = M3_MARKER | 0;
|
---|
| 535 | while (m_len > 255) {
|
---|
| 536 | m_len -= 255;
|
---|
| 537 | *op++ = 0;
|
---|
| 538 | }
|
---|
| 539 | assert(m_len > 0);
|
---|
| 540 | *op++ = m_len;
|
---|
| 541 | }
|
---|
| 542 | *op++ = m_off << 2;
|
---|
| 543 | *op++ = m_off >> 6;
|
---|
| 544 | } else {
|
---|
| 545 | unsigned k;
|
---|
| 546 |
|
---|
| 547 | assert(m_len >= 3);
|
---|
| 548 | assert(m_off > 0x4000);
|
---|
| 549 | assert(m_off <= 0xbfff);
|
---|
| 550 | m_off -= 0x4000;
|
---|
| 551 | k = (m_off & 0x4000) >> 11;
|
---|
| 552 | if (m_len <= M4_MAX_LEN)
|
---|
| 553 | *op++ = M4_MARKER | k | (m_len - 2);
|
---|
| 554 | else {
|
---|
| 555 | m_len -= M4_MAX_LEN;
|
---|
| 556 | *op++ = M4_MARKER | k | 0;
|
---|
| 557 | while (m_len > 255) {
|
---|
| 558 | m_len -= 255;
|
---|
| 559 | *op++ = 0;
|
---|
| 560 | }
|
---|
| 561 | assert(m_len > 0);
|
---|
| 562 | *op++ = m_len;
|
---|
| 563 | }
|
---|
| 564 | *op++ = m_off << 2;
|
---|
| 565 | *op++ = m_off >> 6;
|
---|
| 566 | }
|
---|
| 567 |
|
---|
| 568 | return op;
|
---|
| 569 | }
|
---|
| 570 |
|
---|
| 571 |
|
---|
| 572 | static uint8_t *STORE_RUN(lzo1x_999_t *c, uint8_t *op,
|
---|
| 573 | const uint8_t *ii, unsigned t)
|
---|
| 574 | {
|
---|
| 575 | if (op == c->out && t <= 238) {
|
---|
| 576 | *op++ = 17 + t;
|
---|
| 577 | } else if (t <= 3) {
|
---|
| 578 | op[-2] |= t;
|
---|
| 579 | } else if (t <= 18) {
|
---|
| 580 | *op++ = t - 3;
|
---|
| 581 | } else {
|
---|
| 582 | unsigned tt = t - 18;
|
---|
| 583 |
|
---|
| 584 | *op++ = 0;
|
---|
| 585 | while (tt > 255) {
|
---|
| 586 | tt -= 255;
|
---|
| 587 | *op++ = 0;
|
---|
| 588 | }
|
---|
| 589 | assert(tt > 0);
|
---|
| 590 | *op++ = tt;
|
---|
| 591 | }
|
---|
| 592 | do *op++ = *ii++; while (--t > 0);
|
---|
| 593 |
|
---|
| 594 | return op;
|
---|
| 595 | }
|
---|
| 596 |
|
---|
| 597 |
|
---|
| 598 | static uint8_t *code_run(lzo1x_999_t *c, uint8_t *op, const uint8_t *ii,
|
---|
| 599 | unsigned lit)
|
---|
| 600 | {
|
---|
| 601 | if (lit > 0) {
|
---|
| 602 | assert(m_len >= 2);
|
---|
| 603 | op = STORE_RUN(c, op, ii, lit);
|
---|
| 604 | } else {
|
---|
| 605 | assert(m_len >= 3);
|
---|
| 606 | }
|
---|
| 607 | c->r1_lit = lit;
|
---|
| 608 |
|
---|
| 609 | return op;
|
---|
| 610 | }
|
---|
| 611 |
|
---|
| 612 |
|
---|
| 613 | /***********************************************************************
|
---|
| 614 | //
|
---|
| 615 | ************************************************************************/
|
---|
| 616 | static int len_of_coded_match(unsigned m_len, unsigned m_off, unsigned lit)
|
---|
| 617 | {
|
---|
| 618 | int n = 4;
|
---|
| 619 |
|
---|
| 620 | if (m_len < 2)
|
---|
| 621 | return -1;
|
---|
| 622 | if (m_len == 2)
|
---|
| 623 | return (m_off <= M1_MAX_OFFSET && lit > 0 && lit < 4) ? 2 : -1;
|
---|
| 624 | if (m_len <= M2_MAX_LEN && m_off <= M2_MAX_OFFSET)
|
---|
| 625 | return 2;
|
---|
| 626 | if (m_len == M2_MIN_LEN && m_off <= MX_MAX_OFFSET && lit >= 4)
|
---|
| 627 | return 2;
|
---|
| 628 | if (m_off <= M3_MAX_OFFSET) {
|
---|
| 629 | if (m_len <= M3_MAX_LEN)
|
---|
| 630 | return 3;
|
---|
| 631 | m_len -= M3_MAX_LEN;
|
---|
| 632 | } else if (m_off <= M4_MAX_OFFSET) {
|
---|
| 633 | if (m_len <= M4_MAX_LEN)
|
---|
| 634 | return 3;
|
---|
| 635 | m_len -= M4_MAX_LEN;
|
---|
| 636 | } else
|
---|
| 637 | return -1;
|
---|
| 638 | while (m_len > 255) {
|
---|
| 639 | m_len -= 255;
|
---|
| 640 | n++;
|
---|
| 641 | }
|
---|
| 642 | return n;
|
---|
| 643 | }
|
---|
| 644 |
|
---|
| 645 |
|
---|
| 646 | static int min_gain(unsigned ahead, unsigned lit1,
|
---|
| 647 | unsigned lit2, int l1, int l2, int l3)
|
---|
| 648 | {
|
---|
| 649 | int lazy_match_min_gain = 0;
|
---|
| 650 |
|
---|
| 651 | assert (ahead >= 1);
|
---|
| 652 | lazy_match_min_gain += ahead;
|
---|
| 653 |
|
---|
| 654 | if (lit1 <= 3)
|
---|
| 655 | lazy_match_min_gain += (lit2 <= 3) ? 0 : 2;
|
---|
| 656 | else if (lit1 <= 18)
|
---|
| 657 | lazy_match_min_gain += (lit2 <= 18) ? 0 : 1;
|
---|
| 658 |
|
---|
| 659 | lazy_match_min_gain += (l2 - l1) * 2;
|
---|
| 660 | if (l3 > 0)
|
---|
| 661 | lazy_match_min_gain -= (ahead - l3) * 2;
|
---|
| 662 |
|
---|
| 663 | if (lazy_match_min_gain < 0)
|
---|
| 664 | lazy_match_min_gain = 0;
|
---|
| 665 |
|
---|
| 666 | return lazy_match_min_gain;
|
---|
| 667 | }
|
---|
| 668 |
|
---|
| 669 |
|
---|
| 670 | /***********************************************************************
|
---|
| 671 | //
|
---|
| 672 | ************************************************************************/
|
---|
| 673 | #if defined(SWD_BEST_OFF)
|
---|
| 674 |
|
---|
| 675 | static void better_match(const lzo_swd_p swd,
|
---|
| 676 | unsigned *m_len, unsigned *m_off)
|
---|
| 677 | {
|
---|
| 678 | if (*m_len <= M2_MIN_LEN)
|
---|
| 679 | return;
|
---|
| 680 |
|
---|
| 681 | if (*m_off <= M2_MAX_OFFSET)
|
---|
| 682 | return;
|
---|
| 683 |
|
---|
| 684 | /* M3/M4 -> M2 */
|
---|
| 685 | if (*m_off > M2_MAX_OFFSET
|
---|
| 686 | && *m_len >= M2_MIN_LEN + 1 && *m_len <= M2_MAX_LEN + 1
|
---|
| 687 | && swd->best_off[*m_len-1] && swd->best_off[*m_len-1] <= M2_MAX_OFFSET
|
---|
| 688 | ) {
|
---|
| 689 | *m_len = *m_len - 1;
|
---|
| 690 | *m_off = swd->best_off[*m_len];
|
---|
| 691 | return;
|
---|
| 692 | }
|
---|
| 693 |
|
---|
| 694 | /* M4 -> M2 */
|
---|
| 695 | if (*m_off > M3_MAX_OFFSET
|
---|
| 696 | && *m_len >= M4_MAX_LEN + 1 && *m_len <= M2_MAX_LEN + 2
|
---|
| 697 | && swd->best_off[*m_len-2] && swd->best_off[*m_len-2] <= M2_MAX_OFFSET
|
---|
| 698 | ) {
|
---|
| 699 | *m_len = *m_len - 2;
|
---|
| 700 | *m_off = swd->best_off[*m_len];
|
---|
| 701 | return;
|
---|
| 702 | }
|
---|
| 703 | /* M4 -> M3 */
|
---|
| 704 | if (*m_off > M3_MAX_OFFSET
|
---|
| 705 | && *m_len >= M4_MAX_LEN + 1 && *m_len <= M3_MAX_LEN + 1
|
---|
| 706 | && swd->best_off[*m_len-1] && swd->best_off[*m_len-1] <= M3_MAX_OFFSET
|
---|
| 707 | ) {
|
---|
| 708 | *m_len = *m_len - 1;
|
---|
| 709 | *m_off = swd->best_off[*m_len];
|
---|
| 710 | }
|
---|
| 711 | }
|
---|
| 712 |
|
---|
| 713 | #endif
|
---|
| 714 |
|
---|
| 715 |
|
---|
| 716 | /***********************************************************************
|
---|
| 717 | //
|
---|
| 718 | ************************************************************************/
|
---|
| 719 | static int lzo1x_999_compress_internal(const uint8_t *in, unsigned in_len,
|
---|
| 720 | uint8_t *out, unsigned *out_len,
|
---|
| 721 | void *wrkmem,
|
---|
| 722 | unsigned good_length,
|
---|
| 723 | unsigned max_lazy,
|
---|
| 724 | unsigned max_chain,
|
---|
| 725 | uint32_t use_best_off)
|
---|
| 726 | {
|
---|
| 727 | uint8_t *op;
|
---|
| 728 | const uint8_t *ii;
|
---|
| 729 | unsigned lit;
|
---|
| 730 | unsigned m_len, m_off;
|
---|
| 731 | lzo1x_999_t cc;
|
---|
| 732 | lzo1x_999_t *const c = &cc;
|
---|
| 733 | const lzo_swd_p swd = (lzo_swd_p) wrkmem;
|
---|
| 734 | int r;
|
---|
| 735 |
|
---|
| 736 | c->init = 0;
|
---|
| 737 | c->ip = c->in = in;
|
---|
| 738 | c->in_end = in + in_len;
|
---|
| 739 | c->out = out;
|
---|
| 740 |
|
---|
| 741 | op = out;
|
---|
| 742 | ii = c->ip; /* point to start of literal run */
|
---|
| 743 | lit = 0;
|
---|
| 744 | c->r1_lit = 0;
|
---|
| 745 |
|
---|
| 746 | r = init_match(c, swd, use_best_off);
|
---|
| 747 | if (r != 0)
|
---|
| 748 | return r;
|
---|
| 749 | swd->max_chain = max_chain;
|
---|
| 750 |
|
---|
| 751 | r = find_match(c, swd, 0, 0);
|
---|
| 752 | if (r != 0)
|
---|
| 753 | return r;
|
---|
| 754 |
|
---|
| 755 | while (c->look > 0) {
|
---|
| 756 | unsigned ahead;
|
---|
| 757 | unsigned max_ahead;
|
---|
| 758 | int l1, l2, l3;
|
---|
| 759 |
|
---|
| 760 | m_len = c->m_len;
|
---|
| 761 | m_off = c->m_off;
|
---|
| 762 |
|
---|
| 763 | assert(c->bp == c->ip - c->look);
|
---|
| 764 | assert(c->bp >= in);
|
---|
| 765 | if (lit == 0)
|
---|
| 766 | ii = c->bp;
|
---|
| 767 | assert(ii + lit == c->bp);
|
---|
| 768 | assert(swd->b_char == *(c->bp));
|
---|
| 769 |
|
---|
| 770 | if (m_len < 2
|
---|
| 771 | || (m_len == 2 && (m_off > M1_MAX_OFFSET || lit == 0 || lit >= 4))
|
---|
| 772 | /* Do not accept this match for compressed-data compatibility
|
---|
| 773 | * with LZO v1.01 and before
|
---|
| 774 | * [ might be a problem for decompress() and optimize() ]
|
---|
| 775 | */
|
---|
| 776 | || (m_len == 2 && op == out)
|
---|
| 777 | || (op == out && lit == 0)
|
---|
| 778 | ) {
|
---|
| 779 | /* a literal */
|
---|
| 780 | m_len = 0;
|
---|
| 781 | }
|
---|
| 782 | else if (m_len == M2_MIN_LEN) {
|
---|
| 783 | /* compression ratio improves if we code a literal in some cases */
|
---|
| 784 | if (m_off > MX_MAX_OFFSET && lit >= 4)
|
---|
| 785 | m_len = 0;
|
---|
| 786 | }
|
---|
| 787 |
|
---|
| 788 | if (m_len == 0) {
|
---|
| 789 | /* a literal */
|
---|
| 790 | lit++;
|
---|
| 791 | swd->max_chain = max_chain;
|
---|
| 792 | r = find_match(c, swd, 1, 0);
|
---|
| 793 | assert(r == 0);
|
---|
| 794 | continue;
|
---|
| 795 | }
|
---|
| 796 |
|
---|
| 797 | /* a match */
|
---|
| 798 | #if defined(SWD_BEST_OFF)
|
---|
| 799 | if (swd->use_best_off)
|
---|
| 800 | better_match(swd, &m_len, &m_off);
|
---|
| 801 | #endif
|
---|
| 802 |
|
---|
| 803 | /* shall we try a lazy match ? */
|
---|
| 804 | ahead = 0;
|
---|
| 805 | if (m_len >= max_lazy) {
|
---|
| 806 | /* no */
|
---|
| 807 | l1 = 0;
|
---|
| 808 | max_ahead = 0;
|
---|
| 809 | } else {
|
---|
| 810 | /* yes, try a lazy match */
|
---|
| 811 | l1 = len_of_coded_match(m_len, m_off, lit);
|
---|
| 812 | assert(l1 > 0);
|
---|
| 813 | max_ahead = LZO_MIN(2, (unsigned)l1 - 1);
|
---|
| 814 | }
|
---|
| 815 |
|
---|
| 816 |
|
---|
| 817 | while (ahead < max_ahead && c->look > m_len) {
|
---|
| 818 | int lazy_match_min_gain;
|
---|
| 819 |
|
---|
| 820 | if (m_len >= good_length)
|
---|
| 821 | swd->max_chain = max_chain >> 2;
|
---|
| 822 | else
|
---|
| 823 | swd->max_chain = max_chain;
|
---|
| 824 | r = find_match(c, swd, 1, 0);
|
---|
| 825 | ahead++;
|
---|
| 826 |
|
---|
| 827 | assert(r == 0);
|
---|
| 828 | assert(c->look > 0);
|
---|
| 829 | assert(ii + lit + ahead == c->bp);
|
---|
| 830 |
|
---|
| 831 | if (c->m_len < m_len)
|
---|
| 832 | continue;
|
---|
| 833 | if (c->m_len == m_len && c->m_off >= m_off)
|
---|
| 834 | continue;
|
---|
| 835 | #if defined(SWD_BEST_OFF)
|
---|
| 836 | if (swd->use_best_off)
|
---|
| 837 | better_match(swd, &c->m_len, &c->m_off);
|
---|
| 838 | #endif
|
---|
| 839 | l2 = len_of_coded_match(c->m_len, c->m_off, lit+ahead);
|
---|
| 840 | if (l2 < 0)
|
---|
| 841 | continue;
|
---|
| 842 |
|
---|
| 843 | /* compressed-data compatibility [see above] */
|
---|
| 844 | l3 = (op == out) ? -1 : len_of_coded_match(ahead, m_off, lit);
|
---|
| 845 |
|
---|
| 846 | lazy_match_min_gain = min_gain(ahead, lit, lit+ahead, l1, l2, l3);
|
---|
| 847 | if (c->m_len >= m_len + lazy_match_min_gain) {
|
---|
| 848 | if (l3 > 0) {
|
---|
| 849 | /* code previous run */
|
---|
| 850 | op = code_run(c, op, ii, lit);
|
---|
| 851 | lit = 0;
|
---|
| 852 | /* code shortened match */
|
---|
| 853 | op = code_match(c, op, ahead, m_off);
|
---|
| 854 | } else {
|
---|
| 855 | lit += ahead;
|
---|
| 856 | assert(ii + lit == c->bp);
|
---|
| 857 | }
|
---|
| 858 | goto lazy_match_done;
|
---|
| 859 | }
|
---|
| 860 | }
|
---|
| 861 |
|
---|
| 862 | assert(ii + lit + ahead == c->bp);
|
---|
| 863 |
|
---|
| 864 | /* 1 - code run */
|
---|
| 865 | op = code_run(c, op, ii, lit);
|
---|
| 866 | lit = 0;
|
---|
| 867 |
|
---|
| 868 | /* 2 - code match */
|
---|
| 869 | op = code_match(c, op, m_len, m_off);
|
---|
| 870 | swd->max_chain = max_chain;
|
---|
| 871 | r = find_match(c, swd, m_len, 1+ahead);
|
---|
| 872 | assert(r == 0);
|
---|
| 873 |
|
---|
| 874 | lazy_match_done: ;
|
---|
| 875 | }
|
---|
| 876 |
|
---|
| 877 | /* store final run */
|
---|
| 878 | if (lit > 0)
|
---|
| 879 | op = STORE_RUN(c, op, ii, lit);
|
---|
| 880 |
|
---|
| 881 | #if defined(LZO_EOF_CODE)
|
---|
| 882 | *op++ = M4_MARKER | 1;
|
---|
| 883 | *op++ = 0;
|
---|
| 884 | *op++ = 0;
|
---|
| 885 | #endif
|
---|
| 886 |
|
---|
| 887 | *out_len = op - out;
|
---|
| 888 |
|
---|
| 889 | return LZO_E_OK;
|
---|
| 890 | }
|
---|
| 891 |
|
---|
| 892 |
|
---|
| 893 | /***********************************************************************
|
---|
| 894 | //
|
---|
| 895 | ************************************************************************/
|
---|
| 896 | int lzo1x_999_compress_level(const uint8_t *in, unsigned in_len,
|
---|
| 897 | uint8_t *out, unsigned *out_len,
|
---|
| 898 | void *wrkmem,
|
---|
| 899 | int compression_level)
|
---|
| 900 | {
|
---|
| 901 | static const struct {
|
---|
| 902 | uint16_t good_length;
|
---|
| 903 | uint16_t max_lazy;
|
---|
| 904 | uint16_t max_chain;
|
---|
| 905 | uint16_t use_best_off;
|
---|
| 906 | } c[3] = {
|
---|
| 907 | { 8, 32, 256, 0 },
|
---|
| 908 | { 32, 128, 2048, 1 },
|
---|
| 909 | { SWD_F, SWD_F, 4096, 1 } /* max. compression */
|
---|
| 910 | };
|
---|
| 911 |
|
---|
| 912 | if (compression_level < 7 || compression_level > 9)
|
---|
| 913 | return LZO_E_ERROR;
|
---|
| 914 |
|
---|
| 915 | compression_level -= 7;
|
---|
| 916 | return lzo1x_999_compress_internal(in, in_len, out, out_len, wrkmem,
|
---|
| 917 | c[compression_level].good_length,
|
---|
| 918 | c[compression_level].max_lazy,
|
---|
| 919 | c[compression_level].max_chain,
|
---|
| 920 | c[compression_level].use_best_off);
|
---|
| 921 | }
|
---|