/src/lzo-2.10/src/lzo1b_9x.c

Source
/* lzo1b_9x.c -- implementation of the LZO1B-999 compression algorithm

   This file is part of the LZO real-time data compression library.

   Copyright (C) 1996-2017 Markus Franz Xaver Johannes Oberhumer
   All Rights Reserved.

   The LZO library is free software; you can redistribute it and/or
   modify it under the terms of the GNU General Public License as
   published by the Free Software Foundation; either version 2 of
   the License, or (at your option) any later version.

   The LZO library is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU General Public License for more details.

   You should have received a copy of the GNU General Public License
   along with the LZO library; see the file COPYING.
   If not, write to the Free Software Foundation, Inc.,
   51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.

   Markus F.X.J. Oberhumer
   <markus@oberhumer.com>
   http://www.oberhumer.com/opensource/lzo/
 */


#include "config1b.h"


/***********************************************************************
//
************************************************************************/

#define SWD_N          0xffffL          /* size of ring buffer */
#define SWD_THRESHOLD       2           /* lower limit for match length */
#define SWD_F            2048           /* upper limit for match length */


#define LZO1B 1
#define LZO_COMPRESS_T  lzo1b_999_t
#define lzo_swd_t       lzo1b_999_swd_t
#include "lzo_mchw.ch"



/***********************************************************************
//
************************************************************************/

static lzo_bytep
code_match ( LZO_COMPRESS_T *c, lzo_bytep op, lzo_uint m_len, lzo_uint m_off )
{
    if (m_len <= M2_MAX_LEN && m_off <= M2_MAX_OFFSET)
    {
        assert(m_len >= M2_MIN_LEN);
        assert(m_off >= M2_MIN_OFFSET);

        m_off -= M2_MIN_OFFSET;
        /* code match len + low offset bits */
        *op++ = LZO_BYTE(((m_len - (M2_MIN_LEN - 2)) << M2O_BITS) |
                          (m_off & M2O_MASK));
        /* code high offset bits */
        *op++ = LZO_BYTE(m_off >> M2O_BITS);
        c->m2_m++;
    }
    else
    {
        assert(m_len >= M3_MIN_LEN);
        assert(m_off <= M3_MAX_OFFSET);

        m_off -= M3_MIN_OFFSET - M3_EOF_OFFSET;
        /* code match len */
        if (m_len <= M3_MAX_LEN)
            *op++ = LZO_BYTE(M3_MARKER | (m_len - (M3_MIN_LEN - 1)));
        else
        {
            assert(m_len >= M4_MIN_LEN);
            /* code M4 match len flag */
            *op++ = M4_MARKER;
            /* code match len */
            m_len -= M4_MIN_LEN - 1;
            while (m_len > 255)
            {
                m_len -= 255;
                *op++ = 0;
            }
            assert(m_len > 0);
            *op++ = LZO_BYTE(m_len);
        }
        /* code low offset bits */
        *op++ = LZO_BYTE(m_off & M3O_MASK);
        /* code high offset bits */
        *op++ = LZO_BYTE(m_off >> M3O_BITS);

        c->r1_m_len = 0;
        c->m3_m++;
    }
    return op;
}


/***********************************************************************
// this is a public function, but there is no prototype in a header file
************************************************************************/

LZO_EXTERN(int)
lzo1b_999_compress_callback ( const lzo_bytep in , lzo_uint  in_len,
                                    lzo_bytep out, lzo_uintp out_len,
                                    lzo_voidp wrkmem,
                                    lzo_callback_p cb,
                                    lzo_uint max_chain );

LZO_PUBLIC(int)
lzo1b_999_compress_callback ( const lzo_bytep in , lzo_uint  in_len,
                                    lzo_bytep out, lzo_uintp out_len,
                                    lzo_voidp wrkmem,
                                    lzo_callback_p cb,
                                    lzo_uint max_chain )
{
    lzo_bytep op;
    const lzo_bytep ii;
    lzo_uint lit;
    lzo_uint m_len, m_off;
    LZO_COMPRESS_T cc;
    LZO_COMPRESS_T * const c = &cc;
    lzo_swd_p const swd = (lzo_swd_p) wrkmem;
    int r;

    /* sanity check */
    LZO_COMPILE_TIME_ASSERT(LZO1B_999_MEM_COMPRESS >= SIZEOF_LZO_SWD_T)

    c->init = 0;
    c->ip = c->in = in;
    c->in_end = in + in_len;
    c->cb = cb;
    c->r1_r = c->m3_r = c->m2_m = c->m3_m = 0;

    op = out;
    ii = c->ip;             /* point to start of literal run */
    lit = 0;
    c->r1_m_len = 0;

    r = init_match(c,swd,NULL,0,0);
    if (r != 0)
        return r;
    if (max_chain > 0)
        swd->max_chain = max_chain;

    r = find_match(c,swd,0,0);
    if (r != 0)
        return r;
    while (c->look > 0)
    {
        int lazy_match_min_gain = -1;
        lzo_uint ahead = 0;

        m_len = c->m_len;
        m_off = c->m_off;

#if 0
        printf("%5ld: %5d len:%3d off:%5d\n", (c->ip-c->look)-in, c->look,
                m_len, m_off);
#endif

        assert(c->ip - c->look >= in);
        if (lit == 0)
            ii = c->ip - c->look;
        assert(ii + lit == c->ip - c->look);
        assert(swd->b_char == *(c->ip - c->look));

        if ((m_len < M2_MIN_LEN) ||
            (m_len < M3_MIN_LEN && m_off > M2_MAX_OFFSET))
        {
            m_len = 0;
        }
        else
        {
            assert(c->ip - c->look - m_off >= in);
            assert(c->ip - c->look - m_off + m_len < c->ip);
            assert(lzo_memcmp(c->ip - c->look, c->ip - c->look - m_off,
                              m_len) == 0);

            if (lit > 0)
            {
                /* we have a current literal run: do not try a lazy match,
                   if the literal could be coded into a r1 match */
                if (lit == 1 && c->r1_m_len == M2_MIN_LEN)
                    lazy_match_min_gain = -1;
                else
                    lazy_match_min_gain = 1;

#if (M2_MIN_LEN == 2)
                if (m_len == 2)
                {
                    /* don't code a match of len 2 if we have to
                       code a literal run. Code a literal instead. */
                    m_len = 0;
                }
#endif
#if (M2_MIN_LEN == M3_MIN_LEN)
                if (m_len == M2_MIN_LEN && m_off > M2_MAX_OFFSET)
                {
                    /* don't code a M3 match of len 3 if we have to
                       code a literal run. Code a literal instead. */
                    m_len = 0;
                }
#endif
            }
            else
            {
                /* no current literal run: only try a lazy match,
                   if the literal could be coded into a r1 match */
                if (c->r1_m_len == M2_MIN_LEN)
                    lazy_match_min_gain = 0;
                else
                    lazy_match_min_gain = -1;
            }
        }


        /* try a lazy match */
        if (m_len == 0)
            lazy_match_min_gain = -1;
        if (lazy_match_min_gain >= 0 && c->look > m_len)
        {
            assert(m_len > 0);

            r = find_match(c,swd,1,0);
            assert(r == 0); LZO_UNUSED(r);
            assert(c->look > 0);

            if (m_len <= M2_MAX_LEN && m_off <= M2_MAX_OFFSET &&
                c->m_off > M2_MAX_OFFSET)
                lazy_match_min_gain += 1;

            if (c->m_len >= m_len + lazy_match_min_gain)
            {
                c->lazy++;
#if !defined(NDEBUG)
                m_len = c->m_len;
                m_off = c->m_off;
                assert(lzo_memcmp(c->ip - c->look, c->ip - c->look - m_off,
                                  m_len) == 0);
#endif
                lit++;
                assert(ii + lit == c->ip - c->look);
                continue;
            }
            else
            {
                ahead = 1;
                assert(ii + lit + 1 == c->ip - c->look);
            }
            assert(m_len > 0);
        }
        assert(ii + lit + ahead == c->ip - c->look);


        if (m_len == 0)
        {
            /* a literal */
            lit++;
            r = find_match(c,swd,1,0);
            assert(r == 0); LZO_UNUSED(r);
        }
        else
        {
            /* 1 - store run */
            if (lit > 0)
            {
                /* code current literal run */
                if (lit == 1 && c->r1_m_len == M2_MIN_LEN)
                {
                    /* Code a context sensitive R1 match. */
                    assert((op[-2] >> M2O_BITS) == (M2_MARKER >> M2O_BITS));
                    op[-2] &= M2O_MASK;
                    assert((op[-2] >> M2O_BITS) == 0);
                    /* copy 1 literal */
                    *op++ = *ii++;
                    assert(ii + ahead == c->ip - c->look);
                    c->r1_r++;
                }
                else
                {
                    op = STORE_RUN(op,ii,lit);
                }
                if (lit < R0FAST)
                    c->r1_m_len = m_len;
                else
                    c->r1_m_len = 0;
                lit = 0;
            }
            else
                c->r1_m_len = 0;

            /* 2 - code match */
            op = code_match(c,op,m_len,m_off);
            r = find_match(c,swd,m_len,1+ahead);
            assert(r == 0); LZO_UNUSED(r);
        }

        c->codesize = pd(op, out);
    }


    /* store final run */
    if (lit > 0)
        op = STORE_RUN(op,ii,lit);

#if defined(LZO_EOF_CODE)
    *op++ = M3_MARKER | 1;
    *op++ = 0;
    *op++ = 0;
#endif

    c->codesize = pd(op, out);
    assert(c->textsize == in_len);

    *out_len = pd(op, out);

    if (c->cb && c->cb->nprogress)
        (*c->cb->nprogress)(c->cb, c->textsize, c->codesize, 0);

#if 0
    printf("%ld %ld -> %ld: %ld %ld %ld %ld %ld\n",
        (long) c->textsize, (long)in_len, (long) c->codesize,
        c->r1_r, c->m3_r, c->m2_m, c->m3_m, c->lazy);
#endif
    return LZO_E_OK;
}



/***********************************************************************
//
************************************************************************/

LZO_PUBLIC(int)
lzo1b_999_compress  ( const lzo_bytep in , lzo_uint  in_len,
                            lzo_bytep out, lzo_uintp out_len,
                            lzo_voidp wrkmem )
{
    return lzo1b_999_compress_callback(in,in_len,out,out_len,wrkmem,
                                       (lzo_callback_p) 0, 0);
}


/* vim:set ts=4 sw=4 et: */

Coverage Report

Created: 2025-11-24 06:26

Line	Count	Source
1		/* lzo1b_9x.c -- implementation of the LZO1B-999 compression algorithm
2
3		This file is part of the LZO real-time data compression library.
4
5		Copyright (C) 1996-2017 Markus Franz Xaver Johannes Oberhumer
6		All Rights Reserved.
7
8		The LZO library is free software; you can redistribute it and/or
9		modify it under the terms of the GNU General Public License as
10		published by the Free Software Foundation; either version 2 of
11		the License, or (at your option) any later version.
12
13		The LZO library is distributed in the hope that it will be useful,
14		but WITHOUT ANY WARRANTY; without even the implied warranty of
15		MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16		GNU General Public License for more details.
17
18		You should have received a copy of the GNU General Public License
19		along with the LZO library; see the file COPYING.
20		If not, write to the Free Software Foundation, Inc.,
21		51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
22
23		Markus F.X.J. Oberhumer
24		<markus@oberhumer.com>
25		http://www.oberhumer.com/opensource/lzo/
26		*/
27
28
29		#include "config1b.h"
30
31
32		/***********************************************************************
33		//
34		************************************************************************/
35
36	521	#define SWD_N 0xffffL /* size of ring buffer */
37	3.16M	#define SWD_THRESHOLD 2 /* lower limit for match length */
38	521	#define SWD_F 2048 /* upper limit for match length */
39
40
41		#define LZO1B 1
42	1.04k	#define LZO_COMPRESS_T lzo1b_999_t
43	521	#define lzo_swd_t lzo1b_999_swd_t
44		#include "lzo_mchw.ch"
45
46
47
48		/***********************************************************************
49		//
50		************************************************************************/
51
52		static lzo_bytep
53		code_match ( LZO_COMPRESS_T *c, lzo_bytep op, lzo_uint m_len, lzo_uint m_off )
54	126k	{
55	126k	if (m_len <= M2_MAX_LEN && m_off <= M2_MAX_OFFSET)
56	76.9k	{
57	76.9k	assert(m_len >= M2_MIN_LEN);
58	76.9k	assert(m_off >= M2_MIN_OFFSET);
59
60	76.9k	m_off -= M2_MIN_OFFSET;
61		/* code match len + low offset bits */
62	76.9k	*op++ = LZO_BYTE(((m_len - (M2_MIN_LEN - 2)) << M2O_BITS) \|
63	76.9k	(m_off & M2O_MASK));
64		/* code high offset bits */
65	76.9k	*op++ = LZO_BYTE(m_off >> M2O_BITS);
66	76.9k	c->m2_m++;
67	76.9k	}
68	49.9k	else
69	49.9k	{
70	49.9k	assert(m_len >= M3_MIN_LEN);
71	49.9k	assert(m_off <= M3_MAX_OFFSET);
72
73	49.9k	m_off -= M3_MIN_OFFSET - M3_EOF_OFFSET;
74		/* code match len */
75	49.9k	if (m_len <= M3_MAX_LEN)
76	34.5k	*op++ = LZO_BYTE(M3_MARKER \| (m_len - (M3_MIN_LEN - 1)));
77	15.3k	else
78	15.3k	{
79	15.3k	assert(m_len >= M4_MIN_LEN);
80		/* code M4 match len flag */
81	15.3k	*op++ = M4_MARKER;
82		/* code match len */
83	15.3k	m_len -= M4_MIN_LEN - 1;
84	37.1k	while (m_len > 255)
85	21.8k	{
86	21.8k	m_len -= 255;
87	21.8k	*op++ = 0;
88	21.8k	}
89	15.3k	assert(m_len > 0);
90	15.3k	*op++ = LZO_BYTE(m_len);
91	15.3k	}
92		/* code low offset bits */
93	49.9k	*op++ = LZO_BYTE(m_off & M3O_MASK);
94		/* code high offset bits */
95	49.9k	*op++ = LZO_BYTE(m_off >> M3O_BITS);
96
97	49.9k	c->r1_m_len = 0;
98	49.9k	c->m3_m++;
99	49.9k	}
100	126k	return op;
101	126k	}
102
103
104		/***********************************************************************
105		// this is a public function, but there is no prototype in a header file
106		************************************************************************/
107
108		LZO_EXTERN(int)
109		lzo1b_999_compress_callback ( const lzo_bytep in , lzo_uint in_len,
110		lzo_bytep out, lzo_uintp out_len,
111		lzo_voidp wrkmem,
112		lzo_callback_p cb,
113		lzo_uint max_chain );
114
115		LZO_PUBLIC(int)
116		lzo1b_999_compress_callback ( const lzo_bytep in , lzo_uint in_len,
117		lzo_bytep out, lzo_uintp out_len,
118		lzo_voidp wrkmem,
119		lzo_callback_p cb,
120		lzo_uint max_chain )
121	521	{
122	521	lzo_bytep op;
123	521	const lzo_bytep ii;
124	521	lzo_uint lit;
125	521	lzo_uint m_len, m_off;
126	521	LZO_COMPRESS_T cc;
127	521	LZO_COMPRESS_T * const c = &cc;
128	521	lzo_swd_p const swd = (lzo_swd_p) wrkmem;
129	521	int r;
130
131		/* sanity check */
132	521	LZO_COMPILE_TIME_ASSERT(LZO1B_999_MEM_COMPRESS >= SIZEOF_LZO_SWD_T)
133
134	521	c->init = 0;
135	521	c->ip = c->in = in;
136	521	c->in_end = in + in_len;
137	521	c->cb = cb;
138	521	c->r1_r = c->m3_r = c->m2_m = c->m3_m = 0;
139
140	521	op = out;
141	521	ii = c->ip; /* point to start of literal run */
142	521	lit = 0;
143	521	c->r1_m_len = 0;
144
145	521	r = init_match(c,swd,NULL,0,0);
146	521	if (r != 0)
147	0	return r;
148	521	if (max_chain > 0)
149	0	swd->max_chain = max_chain;
150
151	521	r = find_match(c,swd,0,0);
152	521	if (r != 0)
153	0	return r;
154	3.09M	while (c->look > 0)
155	3.09M	{
156	3.09M	int lazy_match_min_gain = -1;
157	3.09M	lzo_uint ahead = 0;
158
159	3.09M	m_len = c->m_len;
160	3.09M	m_off = c->m_off;
161
162		#if 0
163		printf("%5ld: %5d len:%3d off:%5d\n", (c->ip-c->look)-in, c->look,
164		m_len, m_off);
165		#endif
166
167	3.09M	assert(c->ip - c->look >= in);
168	3.09M	if (lit == 0)
169	127k	ii = c->ip - c->look;
170	3.09M	assert(ii + lit == c->ip - c->look);
171	3.09M	assert(swd->b_char == *(c->ip - c->look));
172
173	3.09M	if ((m_len < M2_MIN_LEN) \|\|
174	147k	(m_len < M3_MIN_LEN && m_off > M2_MAX_OFFSET))
175	2.96M	{
176	2.96M	m_len = 0;
177	2.96M	}
178	136k	else
179	136k	{
180	136k	assert(c->ip - c->look - m_off >= in);
181	136k	assert(c->ip - c->look - m_off + m_len < c->ip);
182	136k	assert(lzo_memcmp(c->ip - c->look, c->ip - c->look - m_off,
183	136k	m_len) == 0);
184
185	136k	if (lit > 0)
186	74.5k	{
187		/* we have a current literal run: do not try a lazy match,
188		if the literal could be coded into a r1 match */
189	74.5k	if (lit == 1 && c->r1_m_len == M2_MIN_LEN)
190	5.84k	lazy_match_min_gain = -1;
191	68.6k	else
192	68.6k	lazy_match_min_gain = 1;
193
194		#if (M2_MIN_LEN == 2)
195		if (m_len == 2)
196		{
197		/* don't code a match of len 2 if we have to
198		code a literal run. Code a literal instead. */
199		m_len = 0;
200		}
201		#endif
202		#if (M2_MIN_LEN == M3_MIN_LEN)
203		if (m_len == M2_MIN_LEN && m_off > M2_MAX_OFFSET)
204		{
205		/* don't code a M3 match of len 3 if we have to
206		code a literal run. Code a literal instead. */
207		m_len = 0;
208		}
209		#endif
210	74.5k	}
211	61.8k	else
212	61.8k	{
213		/* no current literal run: only try a lazy match,
214		if the literal could be coded into a r1 match */
215	61.8k	if (c->r1_m_len == M2_MIN_LEN)
216	4.41k	lazy_match_min_gain = 0;
217	57.3k	else
218	57.3k	lazy_match_min_gain = -1;
219	61.8k	}
220	136k	}
221
222
223		/* try a lazy match */
224	3.09M	if (m_len == 0)
225	2.96M	lazy_match_min_gain = -1;
226	3.09M	if (lazy_match_min_gain >= 0 && c->look > m_len)
227	72.9k	{
228	72.9k	assert(m_len > 0);
229
230	72.9k	r = find_match(c,swd,1,0);
231	72.9k	assert(r == 0); LZO_UNUSED(r);
232	72.9k	assert(c->look > 0);
233
234	72.9k	if (m_len <= M2_MAX_LEN && m_off <= M2_MAX_OFFSET &&
235	48.9k	c->m_off > M2_MAX_OFFSET)
236	1.42k	lazy_match_min_gain += 1;
237
238	72.9k	if (c->m_len >= m_len + lazy_match_min_gain)
239	9.48k	{
240	9.48k	c->lazy++;
241		#if !defined(NDEBUG)
242		m_len = c->m_len;
243		m_off = c->m_off;
244		assert(lzo_memcmp(c->ip - c->look, c->ip - c->look - m_off,
245		m_len) == 0);
246		#endif
247	9.48k	lit++;
248	9.48k	assert(ii + lit == c->ip - c->look);
249	9.48k	continue;
250	9.48k	}
251	63.4k	else
252	63.4k	{
253	63.4k	ahead = 1;
254	63.4k	assert(ii + lit + 1 == c->ip - c->look);
255	63.4k	}
256	72.9k	assert(m_len > 0);
257	63.4k	}
258	3.09M	assert(ii + lit + ahead == c->ip - c->look);
259
260
261	3.08M	if (m_len == 0)
262	2.96M	{
263		/* a literal */
264	2.96M	lit++;
265	2.96M	r = find_match(c,swd,1,0);
266	2.96M	assert(r == 0); LZO_UNUSED(r);
267	2.96M	}
268	126k	else
269	126k	{
270		/* 1 - store run */
271	126k	if (lit > 0)
272	66.3k	{
273		/* code current literal run */
274	66.3k	if (lit == 1 && c->r1_m_len == M2_MIN_LEN)
275	5.84k	{
276		/* Code a context sensitive R1 match. */
277	5.84k	assert((op[-2] >> M2O_BITS) == (M2_MARKER >> M2O_BITS));
278	5.84k	op[-2] &= M2O_MASK;
279	5.84k	assert((op[-2] >> M2O_BITS) == 0);
280		/* copy 1 literal */
281	5.84k	op++ = ii++;
282	5.84k	assert(ii + ahead == c->ip - c->look);
283	5.84k	c->r1_r++;
284	5.84k	}
285	60.5k	else
286	60.5k	{
287	60.5k	op = STORE_RUN(op,ii,lit);
288	60.5k	}
289	66.3k	if (lit < R0FAST)
290	64.8k	c->r1_m_len = m_len;
291	1.48k	else
292	1.48k	c->r1_m_len = 0;
293	66.3k	lit = 0;
294	66.3k	}
295	60.4k	else
296	60.4k	c->r1_m_len = 0;
297
298		/* 2 - code match */
299	126k	op = code_match(c,op,m_len,m_off);
300	126k	r = find_match(c,swd,m_len,1+ahead);
301	126k	assert(r == 0); LZO_UNUSED(r);
302	126k	}
303
304	3.08M	c->codesize = pd(op, out);
305	3.08M	}
306
307
308		/* store final run */
309	521	if (lit > 0)
310	324	op = STORE_RUN(op,ii,lit);
311
312	521	#if defined(LZO_EOF_CODE)
313	521	*op++ = M3_MARKER \| 1;
314	521	*op++ = 0;
315	521	*op++ = 0;
316	521	#endif
317
318	521	c->codesize = pd(op, out);
319	521	assert(c->textsize == in_len);
320
321	521	*out_len = pd(op, out);
322
323	521	if (c->cb && c->cb->nprogress)
324	0	(*c->cb->nprogress)(c->cb, c->textsize, c->codesize, 0);
325
326		#if 0
327		printf("%ld %ld -> %ld: %ld %ld %ld %ld %ld\n",
328		(long) c->textsize, (long)in_len, (long) c->codesize,
329		c->r1_r, c->m3_r, c->m2_m, c->m3_m, c->lazy);
330		#endif
331	521	return LZO_E_OK;
332	521	}
333
334
335
336		/***********************************************************************
337		//
338		************************************************************************/
339
340		LZO_PUBLIC(int)
341		lzo1b_999_compress ( const lzo_bytep in , lzo_uint in_len,
342		lzo_bytep out, lzo_uintp out_len,
343		lzo_voidp wrkmem )
344	521	{
345	521	return lzo1b_999_compress_callback(in,in_len,out,out_len,wrkmem,
346	521	(lzo_callback_p) 0, 0);
347	521	}
348
349
350		/* vim:set ts=4 sw=4 et: */