385 lines
9.2 KiB
C
385 lines
9.2 KiB
C
/* lzo1c_9x.c -- implementation of the LZO1C-999 compression algorithm
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This file is part of the LZO real-time data compression library.
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Copyright (C) 1996-2002 Markus Franz Xaver Johannes Oberhumer
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All Rights Reserved.
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The LZO library is free software; you can redistribute it and/or
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modify it under the terms of the GNU General Public License as
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published by the Free Software Foundation; either version 2 of
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the License, or (at your option) any later version.
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The LZO library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with the LZO library; see the file COPYING.
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If not, write to the Free Software Foundation, Inc.,
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59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
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Markus F.X.J. Oberhumer
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<markus@oberhumer.com>
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*/
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#include <lzoconf.h>
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#if !defined(LZO_999_UNSUPPORTED)
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#include <stdio.h>
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#include "config1c.h"
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#if 0
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#undef NDEBUG
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#include <assert.h>
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#endif
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/***********************************************************************
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//
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************************************************************************/
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#define N 16383 /* size of ring buffer */
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#define THRESHOLD 2 /* lower limit for match length */
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#define F 2048 /* upper limit for match length */
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#define LZO1C
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#define LZO_COMPRESS_T lzo1c_999_t
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#define lzo_swd_t lzo1c_999_swd_t
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#include "lzo_mchw.ch"
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/***********************************************************************
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//
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************************************************************************/
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static lzo_byte *
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code_match ( LZO_COMPRESS_T *c, lzo_byte *op, lzo_uint m_len, lzo_uint m_off )
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{
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if (m_len <= M2_MAX_LEN && m_off <= M2_MAX_OFFSET)
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{
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assert(m_len >= M2_MIN_LEN);
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assert(m_off >= M2_MIN_OFFSET);
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m_off -= M2_MIN_OFFSET;
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/* code match len + low offset bits */
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*op++ = LZO_BYTE(((m_len - (M2_MIN_LEN - 2)) << M2O_BITS) |
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(m_off & M2O_MASK));
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/* code high offset bits */
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*op++ = LZO_BYTE(m_off >> M2O_BITS);
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c->m2_m++;
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}
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else
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{
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assert(m_len >= M3_MIN_LEN);
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assert(m_off <= M3_MAX_OFFSET);
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m_off -= M3_MIN_OFFSET - M3_EOF_OFFSET;
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/* code match len */
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if (m_len <= M3_MAX_LEN)
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*op++ = LZO_BYTE(M3_MARKER | (m_len - (M3_MIN_LEN - 1)));
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else
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{
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assert(m_len >= M4_MIN_LEN);
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/* code M4 match len flag */
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*op++ = M4_MARKER;
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/* code match len */
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m_len -= M4_MIN_LEN - 1;
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while (m_len > 255)
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{
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m_len -= 255;
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*op++ = 0;
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}
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assert(m_len > 0);
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*op++ = LZO_BYTE(m_len);
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}
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/* code low offset bits */
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*op++ = LZO_BYTE(m_off & M3O_MASK);
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/* code high offset bits */
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*op++ = LZO_BYTE(m_off >> M3O_BITS);
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c->r1_m_len = 0;
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c->m3 = op;
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c->m3_m++;
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}
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return op;
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}
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/***********************************************************************
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// this is a public function, but there is no prototype in a header file
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************************************************************************/
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LZO_EXTERN(int)
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lzo1c_999_compress_callback ( const lzo_byte *in , lzo_uint in_len,
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lzo_byte *out, lzo_uintp out_len,
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lzo_voidp wrkmem,
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lzo_progress_callback_t cb,
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lzo_uint max_chain );
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LZO_PUBLIC(int)
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lzo1c_999_compress_callback ( const lzo_byte *in , lzo_uint in_len,
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lzo_byte *out, lzo_uintp out_len,
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lzo_voidp wrkmem,
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lzo_progress_callback_t cb,
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lzo_uint max_chain )
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{
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lzo_byte *op;
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const lzo_byte *ii;
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lzo_uint lit;
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lzo_uint m_len, m_off;
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LZO_COMPRESS_T cc;
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LZO_COMPRESS_T * const c = &cc;
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lzo_swd_t * const swd = (lzo_swd_t *) wrkmem;
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int r;
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#if defined(__LZO_QUERY_COMPRESS)
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if (__LZO_IS_COMPRESS_QUERY(in,in_len,out,out_len,wrkmem))
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return __LZO_QUERY_COMPRESS(in,in_len,out,out_len,wrkmem,1,lzo_sizeof(lzo_swd_t));
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#endif
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/* sanity check */
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if (!lzo_assert(LZO1C_999_MEM_COMPRESS >= lzo_sizeof(lzo_swd_t)))
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return LZO_E_ERROR;
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c->init = 0;
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c->ip = c->in = in;
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c->in_end = in + in_len;
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c->cb = cb;
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c->r1_r = c->m3_r = c->m2_m = c->m3_m = 0;
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op = out;
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ii = c->ip; /* point to start of literal run */
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lit = 0;
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c->r1_m_len = 0;
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c->m3 = out + 1; /* pointer after last m3/m4 match */
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r = init_match(c,swd,NULL,0,0);
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if (r != 0)
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return r;
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if (max_chain > 0)
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swd->max_chain = max_chain;
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r = find_match(c,swd,0,0);
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if (r != 0)
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return r;
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while (c->look > 0)
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{
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int lazy_match_min_gain = -1;
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lzo_uint ahead = 0;
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m_len = c->m_len;
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m_off = c->m_off;
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#if 0
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printf("%5ld: %5d len:%3d off:%5d\n", (c->ip-c->look)-in, c->look,
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m_len, m_off);
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#endif
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assert(c->ip - c->look >= in);
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if (lit == 0)
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ii = c->ip - c->look;
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assert(ii + lit == c->ip - c->look);
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assert(swd->b_char == *(c->ip - c->look));
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if ((m_len < M2_MIN_LEN) ||
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(m_len < M3_MIN_LEN && m_off > M2_MAX_OFFSET))
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{
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m_len = 0;
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}
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else
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{
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assert(c->ip - c->look - m_off >= in);
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assert(c->ip - c->look - m_off + m_len < c->ip);
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assert(lzo_memcmp(c->ip - c->look, c->ip - c->look - m_off,
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m_len) == 0);
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if (lit > 0)
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{
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/* we have a current literal run: do not try a lazy match,
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if the literal could be coded into a r1 or m3 match */
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if (lit == 1 && c->r1_m_len == M2_MIN_LEN)
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lazy_match_min_gain = -1;
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else if (lit == 3 && op == c->m3)
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lazy_match_min_gain = -1;
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else if (lit < 3 && op == c->m3)
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lazy_match_min_gain = 0;
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else
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lazy_match_min_gain = 1;
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#if (M2_MIN_LEN == 2)
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if (m_len == 2)
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{
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/* don't code a match of len 2 if we have to
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code a literal run. Code a literal instead. */
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m_len = 0;
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}
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#endif
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#if (M2_MIN_LEN == M3_MIN_LEN)
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if (m_len == M2_MIN_LEN && m_off > M2_MAX_OFFSET)
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{
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/* don't code a M3 match of len 3 if we have to
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code a literal run. Code a literal instead. */
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m_len = 0;
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}
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#endif
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}
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else
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{
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/* no current literal run: only try a lazy match,
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if the literal could be coded into a r1 or m3 match */
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if (c->r1_m_len == M2_MIN_LEN || op == c->m3)
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lazy_match_min_gain = 0;
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else
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lazy_match_min_gain = -1;
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}
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}
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/* try a lazy match */
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if (m_len == 0)
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lazy_match_min_gain = -1;
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if (lazy_match_min_gain >= 0 && c->look > m_len)
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{
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assert(m_len > 0);
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r = find_match(c,swd,1,0);
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assert(r == 0);
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assert(c->look > 0);
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if (m_len <= M2_MAX_LEN && m_off <= M2_MAX_OFFSET &&
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c->m_off > M2_MAX_OFFSET)
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lazy_match_min_gain += 1;
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if (c->m_len >= m_len + lazy_match_min_gain)
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{
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c->lazy++;
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#if !defined(NDEBUG)
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m_len = c->m_len;
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m_off = c->m_off;
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assert(lzo_memcmp(c->ip - c->look, c->ip - c->look - m_off,
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m_len) == 0);
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#endif
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lit++;
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assert(ii + lit == c->ip - c->look);
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continue;
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}
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else
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{
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ahead = 1;
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assert(ii + lit + 1 == c->ip - c->look);
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}
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assert(m_len > 0);
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}
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assert(ii + lit + ahead == c->ip - c->look);
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if (m_len == 0)
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{
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/* a literal */
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lit++;
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r = find_match(c,swd,1,0);
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assert(r == 0);
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}
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else
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{
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/* 1 - store run */
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if (lit > 0)
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{
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/* code current literal run */
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if (lit == 1 && c->r1_m_len == M2_MIN_LEN)
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{
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/* Code a context sensitive R1 match. */
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assert((op[-2] >> M2O_BITS) == (M2_MARKER >> M2O_BITS));
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op[-2] &= M2O_MASK;
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assert((op[-2] >> M2O_BITS) == 0);
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/* copy 1 literal */
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*op++ = *ii++;
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assert(ii + ahead == c->ip - c->look);
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c->r1_r++;
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}
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else if (lit < 4 && op == c->m3)
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{
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assert((c->m3[-2] >> M3O_BITS) == 0);
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c->m3[-2] |= LZO_BYTE(lit << M3O_BITS);
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MEMCPY_DS(op, ii, lit);
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assert(ii + ahead == c->ip - c->look);
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c->m3_r++;
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}
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else
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{
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op = STORE_RUN(op,ii,lit);
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}
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if (lit < R0FAST)
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c->r1_m_len = m_len;
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else
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c->r1_m_len = 0;
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lit = 0;
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}
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else
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c->r1_m_len = 0;
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/* 2 - code match */
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op = code_match(c,op,m_len,m_off);
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r = find_match(c,swd,m_len,1+ahead);
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assert(r == 0);
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}
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c->codesize = op - out;
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}
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/* store final run */
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if (lit > 0)
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op = STORE_RUN(op,ii,lit);
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#if defined(LZO_EOF_CODE)
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*op++ = M3_MARKER | 1;
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*op++ = 0;
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*op++ = 0;
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#endif
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c->codesize = op - out;
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assert(c->textsize == in_len);
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*out_len = op - out;
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if (c->cb)
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(*c->cb)(c->textsize,c->codesize);
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#if 0
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printf("%ld %ld -> %ld: %ld %ld %ld %ld %ld\n",
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(long) c->textsize, (long)in_len, (long) c->codesize,
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c->r1_r, c->m3_r, c->m2_m, c->m3_m, c->lazy);
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#endif
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return LZO_E_OK;
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}
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/***********************************************************************
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//
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************************************************************************/
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LZO_PUBLIC(int)
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lzo1c_999_compress ( const lzo_byte *in , lzo_uint in_len,
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lzo_byte *out, lzo_uintp out_len,
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lzo_voidp wrkmem )
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{
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return lzo1c_999_compress_callback(in,in_len,out,out_len,wrkmem,
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(lzo_progress_callback_t) 0, 0);
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}
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#endif /* !defined(LZO_999_UNSUPPORTED) */
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/*
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vi:ts=4:et
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*/
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//martysama0134's 2e58d0b8baeb072acdf3afc4a5d1999f
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