lzop: new applet. Busyboxed by Alain Knaff. +7700 bytes.

1 files changed, 920 insertions, 0 deletions

diff --git a/archival/lzo1x_9x.c b/archival/lzo1x_9x.c
new file mode 100644
index 0000000..d30e2e7
--- /dev/null
+++ b/archival/lzo1x_9x.c
@@ -0,0 +1,920 @@
+/* lzo1x_9x.c -- implementation of the LZO1X-999 compression algorithm
+
+   This file is part of the LZO real-time data compression library.
+
+   Copyright (C) 2008 Markus Franz Xaver Johannes Oberhumer
+   Copyright (C) 2007 Markus Franz Xaver Johannes Oberhumer
+   Copyright (C) 2006 Markus Franz Xaver Johannes Oberhumer
+   Copyright (C) 2005 Markus Franz Xaver Johannes Oberhumer
+   Copyright (C) 2004 Markus Franz Xaver Johannes Oberhumer
+   Copyright (C) 2003 Markus Franz Xaver Johannes Oberhumer
+   Copyright (C) 2002 Markus Franz Xaver Johannes Oberhumer
+   Copyright (C) 2001 Markus Franz Xaver Johannes Oberhumer
+   Copyright (C) 2000 Markus Franz Xaver Johannes Oberhumer
+   Copyright (C) 1999 Markus Franz Xaver Johannes Oberhumer
+   Copyright (C) 1998 Markus Franz Xaver Johannes Oberhumer
+   Copyright (C) 1997 Markus Franz Xaver Johannes Oberhumer
+   Copyright (C) 1996 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 "libbb.h"
+
+/* The following is probably only safe on Intel-compatible processors ... */
+#define LZO_UNALIGNED_OK_2
+#define LZO_UNALIGNED_OK_4
+
+#include "liblzo.h"
+
+#define LZO_MAX(a,b)        ((a) >= (b) ? (a) : (b))
+#define LZO_MIN(a,b)        ((a) <= (b) ? (a) : (b))
+#define LZO_MAX3(a,b,c)     ((a) >= (b) ? LZO_MAX(a,c) : LZO_MAX(b,c))
+
+/***********************************************************************
+//
+************************************************************************/
+#define SWD_N           M4_MAX_OFFSET   /* size of ring buffer */
+#define SWD_F           2048           /* upper limit for match length */
+
+#define SWD_BEST_OFF    (LZO_MAX3(M2_MAX_LEN, M3_MAX_LEN, M4_MAX_LEN) + 1)
+
+typedef struct {
+	int init;
+
+	unsigned look;          /* bytes in lookahead buffer */
+
+	unsigned m_len;
+	unsigned m_off;
+
+	const uint8_t *bp;
+	const uint8_t *ip;
+	const uint8_t *in;
+	const uint8_t *in_end;
+	uint8_t *out;
+
+	unsigned r1_lit;
+
+} lzo1x_999_t;
+
+#define getbyte(c)  ((c).ip < (c).in_end ? *((c).ip)++ : (-1))
+
+/* lzo_swd.c -- sliding window dictionary */
+
+/***********************************************************************
+//
+************************************************************************/
+#define SWD_UINT_MAX      USHRT_MAX
+
+#ifndef SWD_HSIZE
+#  define SWD_HSIZE         16384
+#endif
+#ifndef SWD_MAX_CHAIN
+#  define SWD_MAX_CHAIN     2048
+#endif
+
+#define HEAD3(b, p) \
+	( ((0x9f5f * ((((b[p]<<5)^b[p+1])<<5) ^ b[p+2])) >> 5) & (SWD_HSIZE-1) )
+
+#if defined(LZO_UNALIGNED_OK_2)
+#  define HEAD2(b,p)      (* (uint16_t *) &(b[p]))
+#else
+#  define HEAD2(b,p)      (b[p] ^ ((unsigned)b[p+1]<<8))
+#endif
+#define NIL2              SWD_UINT_MAX
+
+typedef struct lzo_swd {
+	/* public - "built-in" */
+
+	/* public - configuration */
+	unsigned max_chain;
+	int use_best_off;
+
+	/* public - output */
+	unsigned m_len;
+	unsigned m_off;
+	unsigned look;
+	int b_char;
+#if defined(SWD_BEST_OFF)
+	unsigned best_off[SWD_BEST_OFF];
+#endif
+
+	/* semi public */
+	lzo1x_999_t *c;
+	unsigned m_pos;
+#if defined(SWD_BEST_OFF)
+	unsigned best_pos[SWD_BEST_OFF];
+#endif
+
+	/* private */
+	unsigned ip;                /* input pointer (lookahead) */
+	unsigned bp;                /* buffer pointer */
+	unsigned rp;                /* remove pointer */
+
+	unsigned node_count;
+	unsigned first_rp;
+
+	uint8_t b[SWD_N + SWD_F];
+	uint8_t b_wrap[SWD_F]; /* must follow b */
+	uint16_t head3[SWD_HSIZE];
+	uint16_t succ3[SWD_N + SWD_F];
+	uint16_t best3[SWD_N + SWD_F];
+	uint16_t llen3[SWD_HSIZE];
+#ifdef HEAD2
+	uint16_t head2[65536L];
+#endif
+} lzo_swd_t, *lzo_swd_p;
+
+#define SIZEOF_LZO_SWD_T    (sizeof(lzo_swd_t))
+
+
+/* Access macro for head3.
+ * head3[key] may be uninitialized, but then its value will never be used.
+ */
+#define s_get_head3(s,key)    s->head3[key]
+
+
+/***********************************************************************
+//
+************************************************************************/
+#define B_SIZE (SWD_N + SWD_F)
+
+static int swd_init(lzo_swd_p s)
+{
+	/* defaults */
+	s->node_count = SWD_N;
+
+	memset(s->llen3, 0, sizeof(s->llen3[0]) * (unsigned)SWD_HSIZE);
+#ifdef HEAD2
+	memset(s->head2, 0xff, sizeof(s->head2[0]) * 65536L);
+	assert(s->head2[0] == NIL2);
+#endif
+
+	s->ip = 0;
+	s->bp = s->ip;
+	s->first_rp = s->ip;
+
+	assert(s->ip + SWD_F <= B_SIZE);
+	s->look = (unsigned) (s->c->in_end - s->c->ip);
+	if (s->look > 0) {
+		if (s->look > SWD_F)
+			s->look = SWD_F;
+		memcpy(&s->b[s->ip],s->c->ip,s->look);
+		s->c->ip += s->look;
+		s->ip += s->look;
+	}
+	if (s->ip == B_SIZE)
+		s->ip = 0;
+
+	s->rp = s->first_rp;
+	if (s->rp >= s->node_count)
+		s->rp -= s->node_count;
+	else
+		s->rp += B_SIZE - s->node_count;
+
+	return LZO_E_OK;
+}
+
+#define swd_pos2off(s,pos) \
+	(s->bp > (pos) ? s->bp - (pos) : B_SIZE - ((pos) - s->bp))
+
+
+/***********************************************************************
+//
+************************************************************************/
+static void swd_getbyte(lzo_swd_p s)
+{
+	int c;
+
+	if ((c = getbyte(*(s->c))) < 0) {
+		if (s->look > 0)
+			--s->look;
+	} else {
+		s->b[s->ip] = c;
+		if (s->ip < SWD_F)
+			s->b_wrap[s->ip] = c;
+	}
+	if (++s->ip == B_SIZE)
+		s->ip = 0;
+	if (++s->bp == B_SIZE)
+		s->bp = 0;
+	if (++s->rp == B_SIZE)
+		s->rp = 0;
+}
+
+
+/***********************************************************************
+// remove node from lists
+************************************************************************/
+static void swd_remove_node(lzo_swd_p s, unsigned node)
+{
+	if (s->node_count == 0) {
+		unsigned key;
+
+		key = HEAD3(s->b,node);
+		assert(s->llen3[key] > 0);
+		--s->llen3[key];
+
+#ifdef HEAD2
+		key = HEAD2(s->b,node);
+		assert(s->head2[key] != NIL2);
+		if ((unsigned) s->head2[key] == node)
+			s->head2[key] = NIL2;
+#endif
+	} else
+		--s->node_count;
+}
+
+
+/***********************************************************************
+//
+************************************************************************/
+static void swd_accept(lzo_swd_p s, unsigned n)
+{
+	assert(n <= s->look);
+
+	while (n--) {
+		unsigned key;
+
+		swd_remove_node(s,s->rp);
+
+		/* add bp into HEAD3 */
+		key = HEAD3(s->b,s->bp);
+		s->succ3[s->bp] = s_get_head3(s,key);
+		s->head3[key] = s->bp;
+		s->best3[s->bp] = SWD_F + 1;
+		s->llen3[key]++;
+		assert(s->llen3[key] <= SWD_N);
+
+#ifdef HEAD2
+		/* add bp into HEAD2 */
+		key = HEAD2(s->b,s->bp);
+		s->head2[key] = s->bp;
+#endif
+
+		swd_getbyte(s);
+	}
+}
+
+
+/***********************************************************************
+//
+************************************************************************/
+static void swd_search(lzo_swd_p s, unsigned node, unsigned cnt)
+{
+	const uint8_t *p1;
+	const uint8_t *p2;
+	const uint8_t *px;
+	unsigned m_len = s->m_len;
+	const uint8_t *b  = s->b;
+	const uint8_t *bp = s->b + s->bp;
+	const uint8_t *bx = s->b + s->bp + s->look;
+	unsigned char scan_end1;
+
+	assert(s->m_len > 0);
+
+	scan_end1 = bp[m_len - 1];
+	for ( ; cnt-- > 0; node = s->succ3[node]) {
+		p1 = bp;
+		p2 = b + node;
+		px = bx;
+
+		assert(m_len < s->look);
+
+		if (p2[m_len - 1] == scan_end1 &&
+		    p2[m_len] == p1[m_len] &&
+		    p2[0] == p1[0] &&
+		    p2[1] == p1[1]) {
+			unsigned i;
+			assert(lzo_memcmp(bp,&b[node],3) == 0);
+				
+			p1 += 2; p2 += 2;
+			do {} while (++p1 < px && *p1 == *++p2);
+			i = p1-bp;
+
+			assert(lzo_memcmp(bp,&b[node],i) == 0);
+
+#if defined(SWD_BEST_OFF)
+			if (i < SWD_BEST_OFF) {
+				if (s->best_pos[i] == 0)
+					s->best_pos[i] = node + 1;
+			}
+#endif
+			if (i > m_len) {
+				s->m_len = m_len = i;
+				s->m_pos = node;
+				if (m_len == s->look)
+					return;
+				if (m_len >= SWD_F)
+					return;
+				if (m_len > (unsigned) s->best3[node])
+					return;
+				scan_end1 = bp[m_len - 1];
+			}
+		}
+	}
+}
+
+
+/***********************************************************************
+//
+************************************************************************/
+#ifdef HEAD2
+
+static int swd_search2(lzo_swd_p s)
+{
+	unsigned key;
+
+	assert(s->look >= 2);
+	assert(s->m_len > 0);
+
+	key = s->head2[ HEAD2(s->b,s->bp) ];
+	if (key == NIL2)
+		return 0;
+	assert(lzo_memcmp(&s->b[s->bp],&s->b[key],2) == 0);
+#if defined(SWD_BEST_OFF)
+	if (s->best_pos[2] == 0)
+		s->best_pos[2] = key + 1;
+#endif
+
+	if (s->m_len < 2) {
+		s->m_len = 2;
+		s->m_pos = key;
+	}
+	return 1;
+}
+
+#endif
+
+
+/***********************************************************************
+//
+************************************************************************/
+static void swd_findbest(lzo_swd_p s)
+{
+	unsigned key;
+	unsigned cnt, node;
+	unsigned len;
+
+	assert(s->m_len > 0);
+
+	/* get current head, add bp into HEAD3 */
+	key = HEAD3(s->b,s->bp);
+	node = s->succ3[s->bp] = s_get_head3(s,key);
+	cnt = s->llen3[key]++;
+	assert(s->llen3[key] <= SWD_N + SWD_F);
+	if (cnt > s->max_chain)
+		cnt = s->max_chain;
+	s->head3[key] = s->bp;
+
+	s->b_char = s->b[s->bp];
+	len = s->m_len;
+	if (s->m_len >= s->look) {
+		if (s->look == 0)
+			s->b_char = -1;
+		s->m_off = 0;
+		s->best3[s->bp] = SWD_F + 1;
+	} else {
+#ifdef HEAD2
+		if (swd_search2(s))
+#endif
+			if (s->look >= 3)
+				swd_search(s,node,cnt);
+		if (s->m_len > len)
+			s->m_off = swd_pos2off(s,s->m_pos);
+		s->best3[s->bp] = s->m_len;
+
+#if defined(SWD_BEST_OFF)
+		if (s->use_best_off) {
+			int i;
+			for (i = 2; i < SWD_BEST_OFF; i++)
+				if (s->best_pos[i] > 0)
+					s->best_off[i] = swd_pos2off(s,s->best_pos[i]-1);
+				else
+					s->best_off[i] = 0;
+		}
+#endif
+	}
+
+	swd_remove_node(s,s->rp);
+
+#ifdef HEAD2
+	/* add bp into HEAD2 */
+	key = HEAD2(s->b,s->bp);
+	s->head2[key] = s->bp;
+#endif
+}
+
+#undef HEAD3
+#undef HEAD2
+#undef s_get_head3
+
+
+/***********************************************************************
+//
+************************************************************************/
+static int init_match(lzo1x_999_t *c, lzo_swd_p s, uint32_t use_best_off)
+{
+	int r;
+
+	assert(!c->init);
+	c->init = 1;
+
+	s->c = c;
+
+	r = swd_init(s);
+	if (r != 0)
+		return r;
+
+	s->use_best_off = use_best_off;
+	return r;
+}
+
+
+/***********************************************************************
+//
+************************************************************************/
+static int find_match(lzo1x_999_t *c, lzo_swd_p s,
+		unsigned this_len, unsigned skip)
+{
+	assert(c->init);
+
+	if (skip > 0) {
+		assert(this_len >= skip);
+		swd_accept(s, this_len - skip);
+	} else {
+		assert(this_len <= 1);
+	}
+
+	s->m_len = 1;
+	s->m_len = 1;
+#ifdef SWD_BEST_OFF
+	if (s->use_best_off)
+		memset(s->best_pos,0,sizeof(s->best_pos));
+#endif
+	swd_findbest(s);
+	c->m_len = s->m_len;
+	c->m_off = s->m_off;
+
+	swd_getbyte(s);
+
+	if (s->b_char < 0) {
+		c->look = 0;
+		c->m_len = 0;
+	} else {
+		c->look = s->look + 1;
+	}
+	c->bp = c->ip - c->look;
+
+	return LZO_E_OK;
+}
+
+/* this is a public functions, but there is no prototype in a header file */
+static int lzo1x_999_compress_internal(const uint8_t *in , unsigned in_len,
+		uint8_t *out, unsigned *out_len,
+		void *wrkmem,
+		unsigned good_length,
+		unsigned max_lazy,
+		unsigned max_chain,
+		uint32_t use_best_off);
+
+
+/***********************************************************************
+//
+************************************************************************/
+static uint8_t *code_match(lzo1x_999_t *c,
+		uint8_t *op, unsigned m_len, unsigned m_off)
+{
+	assert(op > c->out);
+	if (m_len == 2) {
+		assert(m_off <= M1_MAX_OFFSET);
+		assert(c->r1_lit > 0); assert(c->r1_lit < 4);
+		m_off -= 1;
+		*op++ = M1_MARKER | ((m_off & 3) << 2);
+		*op++ = m_off >> 2;
+	} else if (m_len <= M2_MAX_LEN && m_off <= M2_MAX_OFFSET) {
+		assert(m_len >= 3);
+		m_off -= 1;
+		*op++ = ((m_len - 1) << 5) | ((m_off & 7) << 2);
+		*op++ = m_off >> 3;
+		assert(op[-2] >= M2_MARKER);
+	} else if (m_len == M2_MIN_LEN && m_off <= MX_MAX_OFFSET && c->r1_lit >= 4) {
+		assert(m_len == 3);
+		assert(m_off > M2_MAX_OFFSET);
+		m_off -= 1 + M2_MAX_OFFSET;
+		*op++ = M1_MARKER | ((m_off & 3) << 2);
+		*op++ = m_off >> 2;
+	} else if (m_off <= M3_MAX_OFFSET) {
+		assert(m_len >= 3);
+		m_off -= 1;
+		if (m_len <= M3_MAX_LEN)
+			*op++ = M3_MARKER | (m_len - 2);
+		else {
+			m_len -= M3_MAX_LEN;
+			*op++ = M3_MARKER | 0;
+			while (m_len > 255)
+				{
+					m_len -= 255;
+					*op++ = 0;
+				}
+			assert(m_len > 0);
+			*op++ = m_len;
+		}
+		*op++ = m_off << 2;
+		*op++ = m_off >> 6;
+	} else {
+		unsigned k;
+
+		assert(m_len >= 3);
+		assert(m_off > 0x4000); assert(m_off <= 0xbfff);
+		m_off -= 0x4000;
+		k = (m_off & 0x4000) >> 11;
+		if (m_len <= M4_MAX_LEN)
+			*op++ = M4_MARKER | k | (m_len - 2);
+		else {
+			m_len -= M4_MAX_LEN;
+			*op++ = M4_MARKER | k | 0;
+			while (m_len > 255)
+				{
+					m_len -= 255;
+					*op++ = 0;
+				}
+			assert(m_len > 0);
+			*op++ = m_len;
+		}
+		*op++ = m_off << 2;
+		*op++ = m_off >> 6;
+	}
+
+	return op;
+}
+
+
+static uint8_t *STORE_RUN(lzo1x_999_t *c, uint8_t *op,
+		const uint8_t *ii, unsigned t)
+{
+	if (op == c->out && t <= 238) {
+		*op++ = 17 + t;
+	} else if (t <= 3) {
+		op[-2] |= t;
+	} else if (t <= 18) {
+		*op++ = t - 3;
+	} else {
+		unsigned tt = t - 18;
+
+		*op++ = 0;
+		while (tt > 255) {
+			tt -= 255;
+			*op++ = 0;
+		}
+		assert(tt > 0);
+		*op++ = tt;
+	}
+	do *op++ = *ii++; while (--t > 0);
+
+	return op;
+}
+
+
+static uint8_t *code_run(lzo1x_999_t *c, uint8_t *op, const uint8_t *ii,
+		unsigned lit)
+{
+	if (lit > 0) {
+		assert(m_len >= 2);
+		op = STORE_RUN(c,op,ii,lit);
+	} else {
+		assert(m_len >= 3);
+	}
+	c->r1_lit = lit;
+
+	return op;
+}
+
+
+/***********************************************************************
+//
+************************************************************************/
+static int len_of_coded_match(unsigned m_len, unsigned m_off, unsigned lit)
+{
+	int n = 4;
+
+	if (m_len < 2)
+		return -1;
+	if (m_len == 2)
+		return (m_off <= M1_MAX_OFFSET && lit > 0 && lit < 4) ? 2 : -1;
+	if (m_len <= M2_MAX_LEN && m_off <= M2_MAX_OFFSET)
+		return 2;
+	if (m_len == M2_MIN_LEN && m_off <= MX_MAX_OFFSET && lit >= 4)
+		return 2;
+	if (m_off <= M3_MAX_OFFSET) {
+		if (m_len <= M3_MAX_LEN)
+			return 3;
+		m_len -= M3_MAX_LEN;
+	} else if (m_off <= M4_MAX_OFFSET) {
+		if (m_len <= M4_MAX_LEN)
+			return 3;
+		m_len -= M4_MAX_LEN;
+	} else
+		return -1;
+	while (m_len > 255) {
+		m_len -= 255;
+		n++;
+	}
+	return n;
+}
+
+
+static int min_gain(unsigned ahead, unsigned lit1,
+		    unsigned lit2, int l1, int l2, int l3)
+{
+	int lazy_match_min_gain = 0;
+
+	assert (ahead >= 1);
+	lazy_match_min_gain += ahead;
+
+	if (lit1 <= 3)
+		lazy_match_min_gain += (lit2 <= 3) ? 0 : 2;
+	else if (lit1 <= 18)
+		lazy_match_min_gain += (lit2 <= 18) ? 0 : 1;
+
+	lazy_match_min_gain += (l2 - l1) * 2;
+	if (l3 > 0)
+		lazy_match_min_gain -= (ahead - l3) * 2;
+
+	if (lazy_match_min_gain < 0)
+		lazy_match_min_gain = 0;
+
+	return lazy_match_min_gain;
+}
+
+
+/***********************************************************************
+//
+************************************************************************/
+#if defined(SWD_BEST_OFF)
+
+static void better_match(const lzo_swd_p swd,
+			   unsigned *m_len, unsigned *m_off)
+{
+
+	if (*m_len <= M2_MIN_LEN)
+		return;
+
+	if (*m_off <= M2_MAX_OFFSET)
+		return;
+
+	/* M3/M4 -> M2 */
+	if (*m_off > M2_MAX_OFFSET &&
+	    *m_len >= M2_MIN_LEN + 1 && *m_len <= M2_MAX_LEN + 1 &&
+	    swd->best_off[*m_len-1] && swd->best_off[*m_len-1] <= M2_MAX_OFFSET)
+		{
+			*m_len = *m_len - 1;
+			*m_off = swd->best_off[*m_len];
+			return;
+		}
+
+	/* M4 -> M2 */
+	if (*m_off > M3_MAX_OFFSET &&
+	    *m_len >= M4_MAX_LEN + 1 && *m_len <= M2_MAX_LEN + 2 &&
+	    swd->best_off[*m_len-2] && swd->best_off[*m_len-2] <= M2_MAX_OFFSET)
+		{
+			*m_len = *m_len - 2;
+			*m_off = swd->best_off[*m_len];
+			return;
+		}
+	/* M4 -> M3 */
+	if (*m_off > M3_MAX_OFFSET &&
+	    *m_len >= M4_MAX_LEN + 1 && *m_len <= M3_MAX_LEN + 1 &&
+	    swd->best_off[*m_len-1] && swd->best_off[*m_len-1] <= M3_MAX_OFFSET)
+		{
+			*m_len = *m_len - 1;
+			*m_off = swd->best_off[*m_len];
+		}
+}
+
+#endif
+
+
+/***********************************************************************
+//
+************************************************************************/
+static int lzo1x_999_compress_internal(const uint8_t *in, unsigned in_len,
+		uint8_t *out, unsigned *out_len,
+		void *wrkmem,
+		unsigned good_length,
+		unsigned max_lazy,
+		unsigned max_chain,
+		uint32_t use_best_off)
+{
+	uint8_t *op;
+	const uint8_t *ii;
+	unsigned lit;
+	unsigned m_len, m_off;
+	lzo1x_999_t cc;
+	lzo1x_999_t * const c = &cc;
+	lzo_swd_p const swd = (lzo_swd_p) wrkmem;
+	int r;
+
+	c->init = 0;
+	c->ip = c->in = in;
+	c->in_end = in + in_len;
+	c->out = out;
+
+	op = out;
+	ii = c->ip;             /* point to start of literal run */
+	lit = 0;
+	c->r1_lit = 0;
+
+	r = init_match(c, swd, use_best_off);
+	if (r != 0)
+		return r;
+	swd->max_chain = max_chain;
+
+	r = find_match(c, swd, 0, 0);
+	if (r != 0)
+		return r;
+
+	while (c->look > 0) {
+		unsigned ahead;
+		unsigned max_ahead;
+		int l1, l2, l3;
+
+		m_len = c->m_len;
+		m_off = c->m_off;
+
+		assert(c->bp == c->ip - c->look);
+		assert(c->bp >= in);
+		if (lit == 0)
+			ii = c->bp;
+		assert(ii + lit == c->bp);
+		assert(swd->b_char == *(c->bp));
+
+		if ( m_len < 2 ||
+		     (m_len == 2 && (m_off > M1_MAX_OFFSET || lit == 0 || lit >= 4)) ||
+		     /* Do not accept this match for compressed-data compatibility
+		      * with LZO v1.01 and before
+		      * [ might be a problem for decompress() and optimize() ]
+		      */
+		     (m_len == 2 && op == out) ||
+		     (op == out && lit == 0))
+			{
+				/* a literal */
+				m_len = 0;
+			}
+		else if (m_len == M2_MIN_LEN) {
+			/* compression ratio improves if we code a literal in some cases */
+			if (m_off > MX_MAX_OFFSET && lit >= 4)
+				m_len = 0;
+		}
+
+		if (m_len == 0) {
+			/* a literal */
+			lit++;
+			swd->max_chain = max_chain;
+			r = find_match(c,swd,1,0);
+			assert(r == 0);
+			continue;
+		}
+
+		/* a match */
+#if defined(SWD_BEST_OFF)
+		if (swd->use_best_off)
+			better_match(swd,&m_len,&m_off);
+#endif
+
+		/* shall we try a lazy match ? */
+		ahead = 0;
+		if (m_len >= max_lazy) {
+			/* no */
+			l1 = 0;
+			max_ahead = 0;
+		} else {
+			/* yes, try a lazy match */
+			l1 = len_of_coded_match(m_len,m_off,lit);
+			assert(l1 > 0);
+			max_ahead = LZO_MIN(2, (unsigned)l1 - 1);
+		}
+
+
+		while (ahead < max_ahead && c->look > m_len) {
+			int lazy_match_min_gain;
+
+			if (m_len >= good_length)
+				swd->max_chain = max_chain >> 2;
+			else
+				swd->max_chain = max_chain;
+			r = find_match(c,swd,1,0);
+			ahead++;
+
+			assert(r == 0);
+			assert(c->look > 0);
+			assert(ii + lit + ahead == c->bp);
+
+			if (c->m_len < m_len)
+				continue;
+			if (c->m_len == m_len && c->m_off >= m_off)
+				continue;
+#if defined(SWD_BEST_OFF)
+			if (swd->use_best_off)
+				better_match(swd,&c->m_len,&c->m_off);
+#endif
+			l2 = len_of_coded_match(c->m_len,c->m_off,lit+ahead);
+			if (l2 < 0)
+				continue;
+
+			/* compressed-data compatibility [see above] */
+			l3 = (op == out) ? -1 : len_of_coded_match(ahead,m_off,lit);
+
+			lazy_match_min_gain = min_gain(ahead,lit,lit+ahead,l1,l2,l3);
+			if (c->m_len >= m_len + lazy_match_min_gain) {
+				if (l3 > 0) {
+					/* code previous run */
+					op = code_run(c,op,ii,lit);
+					lit = 0;
+					/* code shortened match */
+					op = code_match(c,op,ahead,m_off);
+				} else {
+					lit += ahead;
+					assert(ii + lit == c->bp);
+				}
+				goto lazy_match_done;
+			}
+		}
+
+		assert(ii + lit + ahead == c->bp);
+
+		/* 1 - code run */
+		op = code_run(c,op,ii,lit);
+		lit = 0;
+
+		/* 2 - code match */
+		op = code_match(c,op,m_len,m_off);
+		swd->max_chain = max_chain;
+		r = find_match(c,swd,m_len,1+ahead);
+		assert(r == 0);
+
+ lazy_match_done: ;
+	}
+
+	/* store final run */
+	if (lit > 0)
+		op = STORE_RUN(c,op,ii,lit);
+
+#if defined(LZO_EOF_CODE)
+	*op++ = M4_MARKER | 1;
+	*op++ = 0;
+	*op++ = 0;
+#endif
+
+	*out_len = op - out;
+
+	return LZO_E_OK;
+}
+
+
+/***********************************************************************
+//
+************************************************************************/
+int lzo1x_999_compress_level(const uint8_t *in, unsigned in_len,
+		uint8_t *out, unsigned *out_len,
+		void *wrkmem,
+		int compression_level)
+{
+	static const struct {
+		uint16_t good_length;
+		uint16_t max_lazy;
+		uint16_t max_chain;
+		uint16_t use_best_off;
+	} c[3] = {
+		{     8,    32,  256,   0 },
+		{    32,   128, 2048,   1 },
+		{ SWD_F, SWD_F, 4096,   1 }       /* max. compression */
+	};
+
+	if (compression_level < 7 || compression_level > 9)
+		return LZO_E_ERROR;
+
+	compression_level -= 7;
+	return lzo1x_999_compress_internal(in, in_len, out, out_len, wrkmem,
+					   c[compression_level].good_length,
+					   c[compression_level].max_lazy,
+					   c[compression_level].max_chain,
+					   c[compression_level].use_best_off);
+}