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+/* lzo_swd.ch -- sliding window dictionary
+
+ 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/
+ */
+
+
+#if (LZO_UINT_MAX < LZO_0xffffffffL)
+# error "LZO_UINT_MAX"
+#endif
+
+
+/***********************************************************************
+//
+************************************************************************/
+
+#ifndef SWD_N
+# define SWD_N N
+#endif
+#ifndef SWD_F
+# define SWD_F F
+#endif
+#ifndef SWD_THRESHOLD
+# define SWD_THRESHOLD THRESHOLD
+#endif
+
+/* unsigned type for dictionary access - don't waste memory here */
+#if (0UL + SWD_N + SWD_F + SWD_F < 0UL + USHRT_MAX)
+ typedef unsigned short swd_uint;
+# define SWD_UINT_MAX USHRT_MAX
+#elif (0UL + SWD_N + SWD_F + SWD_F < 0UL + UINT_MAX)
+ typedef unsigned swd_uint;
+# define SWD_UINT_MAX UINT_MAX
+#else
+ typedef lzo_uint swd_uint;
+# define SWD_UINT_MAX LZO_UINT_MAX
+#endif
+#define swd_uintp swd_uint __LZO_MMODEL *
+#define SWD_UINT(x) ((swd_uint)(x))
+
+
+#ifndef SWD_HSIZE
+# define SWD_HSIZE 16384
+#endif
+#ifndef SWD_MAX_CHAIN
+# define SWD_MAX_CHAIN 2048
+#endif
+
+#if !defined(HEAD3)
+#if 1
+# define HEAD3(b,p) \
+ ((DMUL(0x9f5f,(((((lzo_xint)b[p]<<5)^b[p+1])<<5)^b[p+2]))>>5) & (SWD_HSIZE-1))
+#else
+# define HEAD3(b,p) \
+ ((DMUL(0x9f5f,(((((lzo_xint)b[p+2]<<5)^b[p+1])<<5)^b[p]))>>5) & (SWD_HSIZE-1))
+#endif
+#endif
+
+#if (SWD_THRESHOLD == 1) && !defined(HEAD2)
+# if 1 && defined(LZO_UNALIGNED_OK_2)
+# define HEAD2(b,p) (* (lzo_ushortp) &(b[p]))
+# else
+# define HEAD2(b,p) (b[p] ^ ((unsigned)b[p+1]<<8))
+# endif
+# define NIL2 SWD_UINT_MAX
+#endif
+
+
+typedef struct
+{
+/* public - "built-in" */
+ lzo_uint n;
+ lzo_uint f;
+ lzo_uint threshold;
+
+/* public - configuration */
+ lzo_uint max_chain;
+ lzo_uint nice_length;
+ lzo_bool use_best_off;
+ lzo_uint lazy_insert;
+
+/* public - output */
+ lzo_uint m_len;
+ lzo_uint m_off;
+ lzo_uint look;
+ int b_char;
+#if defined(SWD_BEST_OFF)
+ lzo_uint best_off[ SWD_BEST_OFF ];
+#endif
+
+/* semi public */
+ LZO_COMPRESS_T *c;
+ lzo_uint m_pos;
+#if defined(SWD_BEST_OFF)
+ lzo_uint best_pos[ SWD_BEST_OFF ];
+#endif
+
+/* private */
+ const lzo_bytep dict;
+ const lzo_bytep dict_end;
+ lzo_uint dict_len;
+
+/* private */
+ lzo_uint ip; /* input pointer (lookahead) */
+ lzo_uint bp; /* buffer pointer */
+ lzo_uint rp; /* remove pointer */
+ lzo_uint b_size;
+
+ lzo_bytep b_wrap;
+
+ lzo_uint node_count;
+ lzo_uint first_rp;
+
+#if defined(__LZO_MMODEL_HUGE)
+# define A(type, n) ((((n) * sizeof(type)) + 3UL) &~ 3UL)
+
+# define O_b(s) (0L)
+# define O_head3(s) (O_b(s) + A(char, 0UL + SWD_N + SWD_F + SWD_F))
+# define O_succ3(s) (O_head3(s) + A(swd_uint, 0UL + SWD_HSIZE))
+# define O_best3(s) (O_succ3(s) + A(swd_uint, 0UL + SWD_N + SWD_F))
+# define O_llen3(s) (O_best3(s) + A(swd_uint, 0UL + SWD_N + SWD_F))
+# ifdef HEAD2
+# define O_head2(s) (O_llen3(s) + A(swd_uint, 0UL + SWD_HSIZE))
+# define O_END(s) (O_head2(s) + A(swd_uint, 0UL + 65536L))
+# else
+# define O_END(s) (O_llen3(s) + A(swd_uint, 0UL + SWD_HSIZE))
+# endif
+
+# define S_DEF(s,type,off) ((type) ((lzo_bytep)s + 0L + sizeof(*s) + off))
+# define s_b(s) S_DEF(s, lzo_bytep, O_b(s))
+# define s_head3(s) S_DEF(s, swd_uintp, O_head3(s))
+# define s_succ3(s) S_DEF(s, swd_uintp, O_succ3(s))
+# define s_best3(s) S_DEF(s, swd_uintp, O_best3(s))
+# define s_llen3(s) S_DEF(s, swd_uintp, O_llen3(s))
+# ifdef HEAD2
+# define s_head2(s) S_DEF(s, swd_uintp, O_head2(s))
+# endif
+
+#elif defined(__LZO_CHECKER)
+ /* malloc arrays of the exact size to detect any overrun */
+ unsigned char *b;
+ swd_uint *head3;
+ swd_uint *succ3;
+ swd_uint *best3;
+ swd_uint *llen3;
+# ifdef HEAD2
+ swd_uint *head2;
+# endif
+
+#else
+ unsigned char b [ SWD_N + SWD_F + SWD_F ];
+ swd_uint head3 [ SWD_HSIZE ];
+ swd_uint succ3 [ SWD_N + SWD_F ];
+ swd_uint best3 [ SWD_N + SWD_F ];
+ swd_uint llen3 [ SWD_HSIZE ];
+# ifdef HEAD2
+ swd_uint head2 [ 65536L ];
+# endif
+#endif
+}
+lzo_swd_t;
+#define lzo_swd_p lzo_swd_t __LZO_MMODEL *
+
+
+#if defined(__LZO_MMODEL_HUGE)
+#define SIZEOF_LZO_SWD_T O_END(0)
+#else
+#define s_b(s) s->b
+#define s_head3(s) s->head3
+#define s_succ3(s) s->succ3
+#define s_best3(s) s->best3
+#define s_llen3(s) s->llen3
+#ifdef HEAD2
+#define s_head2(s) s->head2
+#endif
+#define SIZEOF_LZO_SWD_T (sizeof(lzo_swd_t))
+#endif
+
+
+/* Access macro for head3.
+ * head3[key] may be uninitialized, but then its value will never be used.
+ */
+#if defined(__LZO_CHECKER)
+# define s_get_head3(s,key) \
+ ((s->llen3[key] == 0) ? SWD_UINT_MAX : s_head3(s)[key])
+#else
+# define s_get_head3(s,key) s_head3(s)[key]
+#endif
+
+
+/***********************************************************************
+//
+************************************************************************/
+
+static
+void swd_initdict(lzo_swd_p s, const lzo_bytep dict, lzo_uint dict_len)
+{
+ s->dict = s->dict_end = NULL;
+ s->dict_len = 0;
+
+ if (!dict || dict_len <= 0)
+ return;
+ if (dict_len > s->n)
+ {
+ dict += dict_len - s->n;
+ dict_len = s->n;
+ }
+
+ s->dict = dict;
+ s->dict_len = dict_len;
+ s->dict_end = dict + dict_len;
+ lzo_memcpy(s_b(s),dict,dict_len);
+ s->ip = dict_len;
+}
+
+
+static
+void swd_insertdict(lzo_swd_p s, lzo_uint node, lzo_uint len)
+{
+ lzo_uint key;
+
+ s->node_count = s->n - len;
+ s->first_rp = node;
+
+ while (len-- > 0)
+ {
+ key = HEAD3(s_b(s),node);
+ s_succ3(s)[node] = s_get_head3(s,key);
+ s_head3(s)[key] = SWD_UINT(node);
+ s_best3(s)[node] = SWD_UINT(s->f + 1);
+ s_llen3(s)[key]++;
+ assert(s_llen3(s)[key] <= SWD_N);
+
+#ifdef HEAD2
+ key = HEAD2(s_b(s),node);
+ s_head2(s)[key] = SWD_UINT(node);
+#endif
+
+ node++;
+ }
+}
+
+
+/***********************************************************************
+//
+************************************************************************/
+
+static
+int swd_init(lzo_swd_p s, const lzo_bytep dict, lzo_uint dict_len)
+{
+ lzo_uint i = 0;
+ int c = 0;
+
+#if defined(__LZO_CHECKER)
+ s->b = malloc(SWD_N + SWD_F + SWD_F);
+ s->head3 = malloc(sizeof(swd_uint) * SWD_HSIZE);
+ s->succ3 = malloc(sizeof(swd_uint) * (SWD_N + SWD_F));
+ s->best3 = malloc(sizeof(swd_uint) * (SWD_N + SWD_F));
+ s->llen3 = malloc(sizeof(swd_uint) * SWD_HSIZE);
+#ifdef HEAD2
+ s->head2 = malloc(sizeof(swd_uint) * 65536L);
+#endif
+#endif
+
+ s->n = SWD_N;
+ s->f = SWD_F;
+ s->threshold = SWD_THRESHOLD;
+
+ /* defaults */
+ s->max_chain = SWD_MAX_CHAIN;
+ s->nice_length = SWD_F;
+ s->use_best_off = 0;
+ s->lazy_insert = 0;
+
+ s->b_size = s->n + s->f;
+#if 0
+ if (2 * s->f >= s->n || s->b_size + s->f >= SWD_UINT_MAX)
+ return LZO_E_ERROR;
+#else
+ LZO_COMPILE_TIME_ASSERT(!(0ul + 2 * SWD_F >= SWD_N))
+ LZO_COMPILE_TIME_ASSERT(!(0ul + SWD_N + SWD_F + SWD_F >= SWD_UINT_MAX))
+#endif
+ s->b_wrap = s_b(s) + s->b_size;
+ s->node_count = s->n;
+
+ lzo_memset(s_llen3(s), 0, sizeof(s_llen3(s)[0]) * (lzo_uint)SWD_HSIZE);
+#ifdef HEAD2
+#if 1
+ lzo_memset(s_head2(s), 0xff, sizeof(s_head2(s)[0]) * 65536L);
+ assert(s_head2(s)[0] == NIL2);
+#else
+ for (i = 0; i < 65536L; i++)
+ s_head2(s)[i] = NIL2;
+#endif
+#endif
+
+ s->ip = 0;
+ swd_initdict(s,dict,dict_len);
+ s->bp = s->ip;
+ s->first_rp = s->ip;
+
+ assert(s->ip + s->f <= s->b_size);
+#if 1
+ s->look = (lzo_uint) (s->c->in_end - s->c->ip);
+ if (s->look > 0)
+ {
+ if (s->look > s->f)
+ s->look = s->f;
+ lzo_memcpy(&s_b(s)[s->ip],s->c->ip,s->look);
+ s->c->ip += s->look;
+ s->ip += s->look;
+ }
+#else
+ s->look = 0;
+ while (s->look < s->f)
+ {
+ if ((c = getbyte(*(s->c))) < 0)
+ break;
+ s_b(s)[s->ip] = LZO_BYTE(c);
+ s->ip++;
+ s->look++;
+ }
+#endif
+ if (s->ip == s->b_size)
+ s->ip = 0;
+
+ if (s->look >= 2 && s->dict_len > 0)
+ swd_insertdict(s,0,s->dict_len);
+
+ s->rp = s->first_rp;
+ if (s->rp >= s->node_count)
+ s->rp -= s->node_count;
+ else
+ s->rp += s->b_size - s->node_count;
+
+#if defined(__LZO_CHECKER)
+ /* initialize memory for the first few HEAD3 (if s->ip is not far
+ * enough ahead to do this job for us). The value doesn't matter. */
+ if (s->look < 3)
+ lzo_memset(&s_b(s)[s->bp+s->look],0,3);
+#endif
+
+ LZO_UNUSED(i);
+ LZO_UNUSED(c);
+ return LZO_E_OK;
+}
+
+
+static
+void swd_exit(lzo_swd_p s)
+{
+#if defined(__LZO_CHECKER)
+ /* free in reverse order of allocations */
+#ifdef HEAD2
+ free(s->head2); s->head2 = NULL;
+#endif
+ free(s->llen3); s->llen3 = NULL;
+ free(s->best3); s->best3 = NULL;
+ free(s->succ3); s->succ3 = NULL;
+ free(s->head3); s->head3 = NULL;
+ free(s->b); s->b = NULL;
+#else
+ LZO_UNUSED(s);
+#endif
+}
+
+
+#define swd_pos2off(s,pos) \
+ (s->bp > (pos) ? s->bp - (pos) : s->b_size - ((pos) - s->bp))
+
+
+/***********************************************************************
+//
+************************************************************************/
+
+static __lzo_inline
+void swd_getbyte(lzo_swd_p s)
+{
+ int c;
+
+ if ((c = getbyte(*(s->c))) < 0)
+ {
+ if (s->look > 0)
+ --s->look;
+#if defined(__LZO_CHECKER)
+ /* initialize memory - value doesn't matter */
+ s_b(s)[s->ip] = 0;
+ if (s->ip < s->f)
+ s->b_wrap[s->ip] = 0;
+#endif
+ }
+ else
+ {
+ s_b(s)[s->ip] = LZO_BYTE(c);
+ if (s->ip < s->f)
+ s->b_wrap[s->ip] = LZO_BYTE(c);
+ }
+ if (++s->ip == s->b_size)
+ s->ip = 0;
+ if (++s->bp == s->b_size)
+ s->bp = 0;
+ if (++s->rp == s->b_size)
+ s->rp = 0;
+}
+
+
+/***********************************************************************
+// remove node from lists
+************************************************************************/
+
+static __lzo_inline
+void swd_remove_node(lzo_swd_p s, lzo_uint node)
+{
+ if (s->node_count == 0)
+ {
+ lzo_uint key;
+
+#ifdef LZO_DEBUG
+ if (s->first_rp != LZO_UINT_MAX)
+ {
+ if (node != s->first_rp)
+ printf("Remove %5u: %5u %5u %5u %5u %6u %6u\n",
+ node, s->rp, s->ip, s->bp, s->first_rp,
+ s->ip - node, s->ip - s->bp);
+ assert(node == s->first_rp);
+ s->first_rp = LZO_UINT_MAX;
+ }
+#endif
+
+ key = HEAD3(s_b(s),node);
+ assert(s_llen3(s)[key] > 0);
+ --s_llen3(s)[key];
+
+#ifdef HEAD2
+ key = HEAD2(s_b(s),node);
+ assert(s_head2(s)[key] != NIL2);
+ if ((lzo_uint) s_head2(s)[key] == node)
+ s_head2(s)[key] = NIL2;
+#endif
+ }
+ else
+ --s->node_count;
+}
+
+
+/***********************************************************************
+//
+************************************************************************/
+
+static
+void swd_accept(lzo_swd_p s, lzo_uint n)
+{
+ assert(n <= s->look);
+
+ while (n--)
+ {
+ lzo_uint key;
+
+ swd_remove_node(s,s->rp);
+
+ /* add bp into HEAD3 */
+ key = HEAD3(s_b(s),s->bp);
+ s_succ3(s)[s->bp] = s_get_head3(s,key);
+ s_head3(s)[key] = SWD_UINT(s->bp);
+ s_best3(s)[s->bp] = SWD_UINT(s->f + 1);
+ s_llen3(s)[key]++;
+ assert(s_llen3(s)[key] <= SWD_N);
+
+#ifdef HEAD2
+ /* add bp into HEAD2 */
+ key = HEAD2(s_b(s),s->bp);
+ s_head2(s)[key] = SWD_UINT(s->bp);
+#endif
+
+ swd_getbyte(s);
+ }
+}
+
+
+/***********************************************************************
+//
+************************************************************************/
+
+static
+void swd_search(lzo_swd_p s, lzo_uint node, lzo_uint cnt)
+{
+ const lzo_bytep p1;
+ const lzo_bytep p2;
+ const lzo_bytep px;
+ lzo_uint m_len = s->m_len;
+ const lzo_bytep b = s_b(s);
+ const lzo_bytep bp = s_b(s) + s->bp;
+ const lzo_bytep bx = s_b(s) + 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(s)[node])
+ {
+ p1 = bp;
+ p2 = b + node;
+ px = bx;
+
+ assert(m_len < s->look);
+
+ if (
+#if 1
+ p2[m_len - 1] == scan_end1 &&
+ p2[m_len] == p1[m_len] &&
+#endif
+ p2[0] == p1[0] &&
+ p2[1] == p1[1])
+ {
+ lzo_uint i;
+ assert(lzo_memcmp(bp,&b[node],3) == 0);
+
+#if 0 && defined(LZO_UNALIGNED_OK_4)
+ p1 += 3; p2 += 3;
+ while (p1 < px && * (const lzo_uint32p) p1 == * (const lzo_uint32p) p2)
+ p1 += 4, p2 += 4;
+ while (p1 < px && *p1 == *p2)
+ p1 += 1, p2 += 1;
+#else
+ p1 += 2; p2 += 2;
+ do {} while (++p1 < px && *p1 == *++p2);
+#endif
+ i = pd(p1, bp);
+
+#ifdef LZO_DEBUG
+ if (lzo_memcmp(bp,&b[node],i) != 0)
+ printf("%5ld %5ld %02x%02x %02x%02x\n",
+ (long)s->bp, (long) node,
+ bp[0], bp[1], b[node], b[node+1]);
+#endif
+ 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 >= s->nice_length)
+ return;
+ if (m_len > (lzo_uint) s_best3(s)[node])
+ return;
+ scan_end1 = bp[m_len - 1];
+ }
+ }
+ }
+}
+
+
+/***********************************************************************
+//
+************************************************************************/
+
+#ifdef HEAD2
+
+static
+lzo_bool swd_search2(lzo_swd_p s)
+{
+ lzo_uint key;
+
+ assert(s->look >= 2);
+ assert(s->m_len > 0);
+
+ key = s_head2(s)[ HEAD2(s_b(s),s->bp) ];
+ if (key == NIL2)
+ return 0;
+#ifdef LZO_DEBUG
+ if (lzo_memcmp(&s_b(s)[s->bp],&s_b(s)[key],2) != 0)
+ printf("%5ld %5ld %02x%02x %02x%02x\n", (long)s->bp, (long)key,
+ s_b(s)[s->bp], s_b(s)[s->bp+1], s_b(s)[key], s_b(s)[key+1]);
+#endif
+ assert(lzo_memcmp(&s_b(s)[s->bp],&s_b(s)[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)
+{
+ lzo_uint key;
+ lzo_uint cnt, node;
+ lzo_uint len;
+
+ assert(s->m_len > 0);
+
+ /* get current head, add bp into HEAD3 */
+ key = HEAD3(s_b(s),s->bp);
+ node = s_succ3(s)[s->bp] = s_get_head3(s,key);
+ cnt = s_llen3(s)[key]++;
+ assert(s_llen3(s)[key] <= SWD_N + SWD_F);
+ if (cnt > s->max_chain && s->max_chain > 0)
+ cnt = s->max_chain;
+ s_head3(s)[key] = SWD_UINT(s->bp);
+
+ s->b_char = s_b(s)[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)[s->bp] = SWD_UINT(s->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)[s->bp] = SWD_UINT(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),s->bp);
+ s_head2(s)[key] = SWD_UINT(s->bp);
+#endif
+}
+
+
+#undef HEAD3
+#undef HEAD2
+#undef s_get_head3
+
+
+/*
+vi:ts=4:et
+*/
+
generated by cgit v1.2.3 (git 2.25.1) at 2024-11-24 20:27:02 +0000