busybox/archival/lzo1x_c.c

/* implementation of the LZO1[XY]-1 compression algorithm

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

   Copyright (C) 1996..2008 Markus Franz Xaver Johannes Oberhumer
   All Rights Reserved.

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

   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.
 */

/***********************************************************************
// compress a block of data.
************************************************************************/
static NOINLINE unsigned
do_compress(const uint8_t* in, unsigned in_len,
		uint8_t* out, unsigned* out_len,
		void* wrkmem)
{
	register const uint8_t* ip;
	uint8_t* op;
	const uint8_t* const in_end = in + in_len;
	const uint8_t* const ip_end = in + in_len - M2_MAX_LEN - 5;
	const uint8_t* ii;
	const void* *const dict = (const void**) wrkmem;

	op = out;
	ip = in;
	ii = ip;

	ip += 4;
	for (;;) {
		register const uint8_t* m_pos;
		unsigned m_off;
		unsigned m_len;
		unsigned dindex;

		D_INDEX1(dindex,ip);
		GINDEX(m_pos,m_off,dict,dindex,in);
		if (LZO_CHECK_MPOS_NON_DET(m_pos,m_off,in,ip,M4_MAX_OFFSET))
			goto literal;
#if 1
		if (m_off <= M2_MAX_OFFSET || m_pos[3] == ip[3])
			goto try_match;
		D_INDEX2(dindex,ip);
#endif
		GINDEX(m_pos,m_off,dict,dindex,in);
		if (LZO_CHECK_MPOS_NON_DET(m_pos,m_off,in,ip,M4_MAX_OFFSET))
			goto literal;
		if (m_off <= M2_MAX_OFFSET || m_pos[3] == ip[3])
			goto try_match;
		goto literal;

 try_match:
#if 1 && defined(LZO_UNALIGNED_OK_2)
		if (* (const lzo_ushortp) m_pos != * (const lzo_ushortp) ip)
#else
		if (m_pos[0] != ip[0] || m_pos[1] != ip[1])
#endif
		{
		} else {
			if (m_pos[2] == ip[2]) {
#if 0
				if (m_off <= M2_MAX_OFFSET)
					goto match;
				if (lit <= 3)
					goto match;
				if (lit == 3) {			  /* better compression, but slower */
					assert(op - 2 > out); op[-2] |= (uint8_t)(3);
					*op++ = *ii++; *op++ = *ii++; *op++ = *ii++;
					goto code_match;
				}
				if (m_pos[3] == ip[3])
#endif
					goto match;
			}
			else {
				/* still need a better way for finding M1 matches */
#if 0
				/* a M1 match */
#if 0
				if (m_off <= M1_MAX_OFFSET && lit > 0 && lit <= 3)
#else
				if (m_off <= M1_MAX_OFFSET && lit == 3)
#endif
				{
					register unsigned t;

					t = lit;
					assert(op - 2 > out); op[-2] |= (uint8_t)(t);
					do *op++ = *ii++; while (--t > 0);
					assert(ii == ip);
					m_off -= 1;
					*op++ = (uint8_t)(M1_MARKER | ((m_off & 3) << 2));
					*op++ = (uint8_t)(m_off >> 2);
					ip += 2;
					goto match_done;
				}
#endif
			}
		}

		/* a literal */
 literal:
		UPDATE_I(dict, 0, dindex, ip, in);
		++ip;
		if (ip >= ip_end)
			break;
		continue;

		/* a match */
match:
		UPDATE_I(dict, 0, dindex, ip, in);
		/* store current literal run */
		if (pd(ip, ii) > 0) {
			register unsigned t = pd(ip, ii);

			if (t <= 3) {
				assert(op - 2 > out);
				op[-2] |= (uint8_t)(t);
			}
			else if (t <= 18)
				*op++ = (uint8_t)(t - 3);
			else {
				register unsigned tt = t - 18;

				*op++ = 0;
				while (tt > 255) {
					tt -= 255;
					*op++ = 0;
				}
				assert(tt > 0);
				*op++ = (uint8_t)(tt);
			}
			do *op++ = *ii++; while (--t > 0);
		}

		/* code the match */
		assert(ii == ip);
		ip += 3;
		if (m_pos[3] != *ip++ || m_pos[4] != *ip++ || m_pos[5] != *ip++
		 || m_pos[6] != *ip++ || m_pos[7] != *ip++ || m_pos[8] != *ip++
#ifdef LZO1Y
		 || m_pos[ 9] != *ip++ || m_pos[10] != *ip++ || m_pos[11] != *ip++
		 || m_pos[12] != *ip++ || m_pos[13] != *ip++ || m_pos[14] != *ip++
#endif
		) {
			--ip;
			m_len = pd(ip, ii);
			assert(m_len >= 3);
			assert(m_len <= M2_MAX_LEN);

			if (m_off <= M2_MAX_OFFSET) {
				m_off -= 1;
#if defined(LZO1X)
				*op++ = (uint8_t)(((m_len - 1) << 5) | ((m_off & 7) << 2));
				*op++ = (uint8_t)(m_off >> 3);
#elif defined(LZO1Y)
				*op++ = (uint8_t)(((m_len + 1) << 4) | ((m_off & 3) << 2));
				*op++ = (uint8_t)(m_off >> 2);
#endif
			}
			else if (m_off <= M3_MAX_OFFSET) {
				m_off -= 1;
				*op++ = (uint8_t)(M3_MARKER | (m_len - 2));
				goto m3_m4_offset;
			} else {
#if defined(LZO1X)
				m_off -= 0x4000;
				assert(m_off > 0);
				assert(m_off <= 0x7fff);
				*op++ = (uint8_t)(M4_MARKER | ((m_off & 0x4000) >> 11) | (m_len - 2));
				goto m3_m4_offset;
#elif defined(LZO1Y)
				goto m4_match;
#endif
			}
		}
		else {
			{
				const uint8_t* end = in_end;
				const uint8_t* m = m_pos + M2_MAX_LEN + 1;
				while (ip < end && *m == *ip)
					m++, ip++;
				m_len = pd(ip, ii);
			}
			assert(m_len > M2_MAX_LEN);

			if (m_off <= M3_MAX_OFFSET) {
				m_off -= 1;
				if (m_len <= 33)
					*op++ = (uint8_t)(M3_MARKER | (m_len - 2));
				else {
					m_len -= 33;
					*op++ = M3_MARKER | 0;
					goto m3_m4_len;
				}
			} else {
#if defined(LZO1Y)
 m4_match:
#endif
				m_off -= 0x4000;
				assert(m_off > 0);
				assert(m_off <= 0x7fff);
				if (m_len <= M4_MAX_LEN)
					*op++ = (uint8_t)(M4_MARKER | ((m_off & 0x4000) >> 11) | (m_len - 2));
				else {
					m_len -= M4_MAX_LEN;
					*op++ = (uint8_t)(M4_MARKER | ((m_off & 0x4000) >> 11));
 m3_m4_len:
					while (m_len > 255) {
						m_len -= 255;
						*op++ = 0;
					}
					assert(m_len > 0);
					*op++ = (uint8_t)(m_len);
				}
			}
 m3_m4_offset:
			*op++ = (uint8_t)((m_off & 63) << 2);
			*op++ = (uint8_t)(m_off >> 6);
		}
#if 0
 match_done:
#endif
		ii = ip;
		if (ip >= ip_end)
			break;
	}

	*out_len = pd(op, out);
	return pd(in_end, ii);
}

/***********************************************************************
// public entry point
************************************************************************/
int DO_COMPRESS(const uint8_t* in, unsigned in_len,
		uint8_t* out, unsigned* out_len,
		void* wrkmem)
{
	uint8_t* op = out;
	unsigned t;

	if (in_len <= M2_MAX_LEN + 5)
		t = in_len;
	else {
		t = do_compress(in,in_len,op,out_len,wrkmem);
		op += *out_len;
	}

	if (t > 0) {
		const uint8_t* ii = in + in_len - t;

		if (op == out && t <= 238)
			*op++ = (uint8_t)(17 + t);
		else if (t <= 3)
			op[-2] |= (uint8_t)(t);
		else if (t <= 18)
			*op++ = (uint8_t)(t - 3);
		else {
			unsigned tt = t - 18;

			*op++ = 0;
			while (tt > 255) {
				tt -= 255;
				*op++ = 0;
			}
			assert(tt > 0);
			*op++ = (uint8_t)(tt);
		}
		do *op++ = *ii++; while (--t > 0);
	}

	*op++ = M4_MARKER | 1;
	*op++ = 0;
	*op++ = 0;

	*out_len = pd(op, out);
	return 0; /*LZO_E_OK*/
}
1	niro	984	/* implementation of the LZO1[XY]-1 compression algorithm
2
3			This file is part of the LZO real-time data compression library.
4
5			Copyright (C) 1996..2008 Markus Franz Xaver Johannes Oberhumer
6			All Rights Reserved.
7
8			Markus F.X.J. Oberhumer <markus@oberhumer.com>
9			http://www.oberhumer.com/opensource/lzo/
10
11			The LZO library is free software; you can redistribute it and/or
12			modify it under the terms of the GNU General Public License as
13			published by the Free Software Foundation; either version 2 of
14			the License, or (at your option) any later version.
15
16			The LZO library is distributed in the hope that it will be useful,
17			but WITHOUT ANY WARRANTY; without even the implied warranty of
18			MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
19			GNU General Public License for more details.
20
21			You should have received a copy of the GNU General Public License
22			along with the LZO library; see the file COPYING.
23			If not, write to the Free Software Foundation, Inc.,
24			51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
25			*/
26
27			/***********************************************************************
28			// compress a block of data.
29			************************************************************************/
30			static NOINLINE unsigned
31			do_compress(const uint8_t* in, unsigned in_len,
32			uint8_t* out, unsigned* out_len,
33			void* wrkmem)
34			{
35			register const uint8_t* ip;
36			uint8_t* op;
37			const uint8_t* const in_end = in + in_len;
38			const uint8_t* const ip_end = in + in_len - M2_MAX_LEN - 5;
39			const uint8_t* ii;
40			const void* const dict = (const void*) wrkmem;
41
42			op = out;
43			ip = in;
44			ii = ip;
45
46			ip += 4;
47			for (;;) {
48			register const uint8_t* m_pos;
49			unsigned m_off;
50			unsigned m_len;
51			unsigned dindex;
52
53			D_INDEX1(dindex,ip);
54			GINDEX(m_pos,m_off,dict,dindex,in);
55			if (LZO_CHECK_MPOS_NON_DET(m_pos,m_off,in,ip,M4_MAX_OFFSET))
56			goto literal;
57			#if 1
58			if (m_off <= M2_MAX_OFFSET \|\| m_pos[3] == ip[3])
59			goto try_match;
60			D_INDEX2(dindex,ip);
61			#endif
62			GINDEX(m_pos,m_off,dict,dindex,in);
63			if (LZO_CHECK_MPOS_NON_DET(m_pos,m_off,in,ip,M4_MAX_OFFSET))
64			goto literal;
65			if (m_off <= M2_MAX_OFFSET \|\| m_pos[3] == ip[3])
66			goto try_match;
67			goto literal;
68
69			try_match:
70			#if 1 && defined(LZO_UNALIGNED_OK_2)
71			if (* (const lzo_ushortp) m_pos != * (const lzo_ushortp) ip)
72			#else
73			if (m_pos[0] != ip[0] \|\| m_pos[1] != ip[1])
74			#endif
75			{
76			} else {
77			if (m_pos[2] == ip[2]) {
78			#if 0
79			if (m_off <= M2_MAX_OFFSET)
80			goto match;
81			if (lit <= 3)
82			goto match;
83			if (lit == 3) { /* better compression, but slower */
84			assert(op - 2 > out); op[-2] \|= (uint8_t)(3);
85			op++ = ii++; op++ = ii++; op++ = ii++;
86			goto code_match;
87			}
88			if (m_pos[3] == ip[3])
89			#endif
90			goto match;
91			}
92			else {
93			/* still need a better way for finding M1 matches */
94			#if 0
95			/* a M1 match */
96			#if 0
97			if (m_off <= M1_MAX_OFFSET && lit > 0 && lit <= 3)
98			#else
99			if (m_off <= M1_MAX_OFFSET && lit == 3)
100			#endif
101			{
102			register unsigned t;
103
104			t = lit;
105			assert(op - 2 > out); op[-2] \|= (uint8_t)(t);
106			do op++ = ii++; while (--t > 0);
107			assert(ii == ip);
108			m_off -= 1;
109			*op++ = (uint8_t)(M1_MARKER \| ((m_off & 3) << 2));
110			*op++ = (uint8_t)(m_off >> 2);
111			ip += 2;
112			goto match_done;
113			}
114			#endif
115			}
116			}
117
118			/* a literal */
119			literal:
120			UPDATE_I(dict, 0, dindex, ip, in);
121			++ip;
122			if (ip >= ip_end)
123			break;
124			continue;
125
126			/* a match */
127			match:
128			UPDATE_I(dict, 0, dindex, ip, in);
129			/* store current literal run */
130			if (pd(ip, ii) > 0) {
131			register unsigned t = pd(ip, ii);
132
133			if (t <= 3) {
134			assert(op - 2 > out);
135			op[-2] \|= (uint8_t)(t);
136			}
137			else if (t <= 18)
138			*op++ = (uint8_t)(t - 3);
139			else {
140			register unsigned tt = t - 18;
141
142			*op++ = 0;
143			while (tt > 255) {
144			tt -= 255;
145			*op++ = 0;
146			}
147			assert(tt > 0);
148			*op++ = (uint8_t)(tt);
149			}
150			do op++ = ii++; while (--t > 0);
151			}
152
153			/* code the match */
154			assert(ii == ip);
155			ip += 3;
156			if (m_pos[3] != ip++ \|\| m_pos[4] != ip++ \|\| m_pos[5] != *ip++
157			\|\| m_pos[6] != ip++ \|\| m_pos[7] != ip++ \|\| m_pos[8] != *ip++
158			#ifdef LZO1Y
159			\|\| m_pos[ 9] != ip++ \|\| m_pos[10] != ip++ \|\| m_pos[11] != *ip++
160			\|\| m_pos[12] != ip++ \|\| m_pos[13] != ip++ \|\| m_pos[14] != *ip++
161			#endif
162			) {
163			--ip;
164			m_len = pd(ip, ii);
165			assert(m_len >= 3);
166			assert(m_len <= M2_MAX_LEN);
167
168			if (m_off <= M2_MAX_OFFSET) {
169			m_off -= 1;
170			#if defined(LZO1X)
171			*op++ = (uint8_t)(((m_len - 1) << 5) \| ((m_off & 7) << 2));
172			*op++ = (uint8_t)(m_off >> 3);
173			#elif defined(LZO1Y)
174			*op++ = (uint8_t)(((m_len + 1) << 4) \| ((m_off & 3) << 2));
175			*op++ = (uint8_t)(m_off >> 2);
176			#endif
177			}
178			else if (m_off <= M3_MAX_OFFSET) {
179			m_off -= 1;
180			*op++ = (uint8_t)(M3_MARKER \| (m_len - 2));
181			goto m3_m4_offset;
182			} else {
183			#if defined(LZO1X)
184			m_off -= 0x4000;
185			assert(m_off > 0);
186			assert(m_off <= 0x7fff);
187			*op++ = (uint8_t)(M4_MARKER \| ((m_off & 0x4000) >> 11) \| (m_len - 2));
188			goto m3_m4_offset;
189			#elif defined(LZO1Y)
190			goto m4_match;
191			#endif
192			}
193			}
194			else {
195			{
196			const uint8_t* end = in_end;
197			const uint8_t* m = m_pos + M2_MAX_LEN + 1;
198			while (ip < end && m == ip)
199			m++, ip++;
200			m_len = pd(ip, ii);
201			}
202			assert(m_len > M2_MAX_LEN);
203
204			if (m_off <= M3_MAX_OFFSET) {
205			m_off -= 1;
206			if (m_len <= 33)
207			*op++ = (uint8_t)(M3_MARKER \| (m_len - 2));
208			else {
209			m_len -= 33;
210			*op++ = M3_MARKER \| 0;
211			goto m3_m4_len;
212			}
213			} else {
214			#if defined(LZO1Y)
215			m4_match:
216			#endif
217			m_off -= 0x4000;
218			assert(m_off > 0);
219			assert(m_off <= 0x7fff);
220			if (m_len <= M4_MAX_LEN)
221			*op++ = (uint8_t)(M4_MARKER \| ((m_off & 0x4000) >> 11) \| (m_len - 2));
222			else {
223			m_len -= M4_MAX_LEN;
224			*op++ = (uint8_t)(M4_MARKER \| ((m_off & 0x4000) >> 11));
225			m3_m4_len:
226			while (m_len > 255) {
227			m_len -= 255;
228			*op++ = 0;
229			}
230			assert(m_len > 0);
231			*op++ = (uint8_t)(m_len);
232			}
233			}
234			m3_m4_offset:
235			*op++ = (uint8_t)((m_off & 63) << 2);
236			*op++ = (uint8_t)(m_off >> 6);
237			}
238			#if 0
239			match_done:
240			#endif
241			ii = ip;
242			if (ip >= ip_end)
243			break;
244			}
245
246			*out_len = pd(op, out);
247			return pd(in_end, ii);
248			}
249
250			/***********************************************************************
251			// public entry point
252			************************************************************************/
253			int DO_COMPRESS(const uint8_t* in, unsigned in_len,
254			uint8_t* out, unsigned* out_len,
255			void* wrkmem)
256			{
257			uint8_t* op = out;
258			unsigned t;
259
260			if (in_len <= M2_MAX_LEN + 5)
261			t = in_len;
262			else {
263			t = do_compress(in,in_len,op,out_len,wrkmem);
264			op += *out_len;
265			}
266
267			if (t > 0) {
268			const uint8_t* ii = in + in_len - t;
269
270			if (op == out && t <= 238)
271			*op++ = (uint8_t)(17 + t);
272			else if (t <= 3)
273			op[-2] \|= (uint8_t)(t);
274			else if (t <= 18)
275			*op++ = (uint8_t)(t - 3);
276			else {
277			unsigned tt = t - 18;
278
279			*op++ = 0;
280			while (tt > 255) {
281			tt -= 255;
282			*op++ = 0;
283			}
284			assert(tt > 0);
285			*op++ = (uint8_t)(tt);
286			}
287			do op++ = ii++; while (--t > 0);
288			}
289
290			*op++ = M4_MARKER \| 1;
291			*op++ = 0;
292			*op++ = 0;
293
294			*out_len = pd(op, out);
295			return 0; /LZO_E_OK/
296			}