src/integrity.c \
src/iterate_dir.c \
src/join.c \
+ src/lcpit_matchfinder.c \
+ src/lcpit_matchfinder_templates.h \
src/lookup_table.c \
- src/lz_lcp_interval_tree.c \
- src/lz_linked_suffix_array.c \
- src/lz_mf.c \
src/lz_repsearch.c \
- src/lz_suffix_array_utils.c \
src/lzms_common.c \
src/lzms_compress.c \
src/lzms_decompress.c \
include/wimlib/inode.h \
include/wimlib/inode_table.h \
include/wimlib/integrity.h \
+ include/wimlib/lcpit_matchfinder.h
include/wimlib/list.h \
include/wimlib/lookup_table.h \
include/wimlib/lz_extend.h \
include/wimlib/lz_hash.h \
- include/wimlib/lz_mf.h \
- include/wimlib/lz_mf_ops.h \
include/wimlib/lz_repsearch.h \
- include/wimlib/lz_suffix_array_utils.h \
include/wimlib/lzms_common.h \
include/wimlib/lzms_constants.h \
include/wimlib/lzx_common.h \
#include "wimlib/types.h"
extern void
-divsufsort(const u8 *T, u32 *SA, u32 n, u32 *bucket_A, u32 *bucket_B);
+divsufsort(const u8 *T, u32 *SA, u32 n, u32 *tmp);
-#define DIVSUFSORT_TMP1_LEN (256) /* bucket_A */
-#define DIVSUFSORT_TMP2_LEN (256 * 256) /* bucket_B */
+#define DIVSUFSORT_TMP_LEN (256 + (256 * 256))
#endif /* _WIMLIB_DIVSUFSORT_H */
--- /dev/null
+/*
+ * lcpit_matchfinder.h
+ *
+ * A match-finder for Lempel-Ziv compression based on bottom-up construction and
+ * traversal of the Longest Common Prefix (LCP) interval tree.
+ *
+ * Author: Eric Biggers
+ * Year: 2014, 2015
+ *
+ * The author dedicates this file to the public domain.
+ * You can do whatever you want with this file.
+ */
+
+#ifndef _LCPIT_MATCHFINDER_H
+#define _LCPIT_MATCHFINDER_H
+
+#include "wimlib/types.h"
+
+struct lcpit_matchfinder {
+
+ bool huge_mode;
+
+ u32 cur_pos;
+
+ /* Mapping: suffix index ("window position") => lcp-interval index */
+ u32 *pos_data;
+
+ /* Mapping: lcp-interval index => lcp-interval data
+ *
+ * Initially, the lcp-interval data for an lcp-interval contains that
+ * interval's lcp and superinterval index.
+ *
+ * After a lcp-interval is visited during match-finding, its
+ * lcp-interval data contains that interval's lcp and the position of
+ * the next suffix to consider as a match when matching against that
+ * lcp-interval. */
+ union {
+ u32 *intervals;
+ u64 *intervals64;
+ };
+
+ /* The suffix array */
+ u32 *SA;
+
+ u32 min_match_len;
+ u32 nice_match_len;
+};
+
+struct lz_match {
+ u32 length;
+ u32 offset;
+};
+
+extern u64
+lcpit_matchfinder_get_needed_memory(size_t max_bufsize);
+
+extern bool
+lcpit_matchfinder_init(struct lcpit_matchfinder *mf, size_t max_bufsize,
+ u32 min_match_len, u32 nice_match_len);
+
+extern void
+lcpit_matchfinder_destroy(struct lcpit_matchfinder *mf);
+
+extern void
+lcpit_matchfinder_load_buffer(struct lcpit_matchfinder *mf, const u8 *T, u32 n);
+
+extern u32
+lcpit_matchfinder_get_matches(struct lcpit_matchfinder *mf,
+ struct lz_match *matches);
+
+extern void
+lcpit_matchfinder_skip_bytes(struct lcpit_matchfinder *mf, u32 count);
+
+#endif /* _LCPIT_MATCHFINDER_H */
+++ /dev/null
-/*
- * lz_mf.h
- *
- * Interface for Lempel-Ziv match-finders.
- *
- * Copyright (c) 2014 Eric Biggers. All rights reserved.
- *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions
- * are met:
- *
- * 1. Redistributions of source code must retain the above copyright
- * notice, this list of conditions and the following disclaimer.
- *
- * 2. Redistributions in binary form must reproduce the above copyright
- * notice, this list of conditions and the following disclaimer in the
- * documentation and/or other materials provided with the distribution.
- *
- * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS "AS IS" AND
- * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
- * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
- * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE
- * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
- * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
- * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
- * BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
- * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
- * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
- * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
- */
-
-/*
- * Example usage of the match-finder API:
- *
- * ----------------------------------------------------------------------------
- *
- * Fill in a 'struct lz_mf_params'.
- * (Optional) Call lz_mf_params_valid() to validate the parameters.
- * Call lz_mf_alloc() to allocate the match-finder.
- * For each block of data to be compressed:
- * Call lz_mf_load_window() to load the block into the match finder.
- * While the block is not yet fully compressed:
- * Call lz_mf_get_matches() to get matches at the current position.
- * If matches were found:
- * Output the longest match.
- * Call lz_mf_skip_positions() to skip the remaining length of the match.
- * Else:
- * Output a literal.
- * End If
- * End While
- * End For
- * Call lz_mf_free() to free the match-finder.
- *
- * ----------------------------------------------------------------------------
- *
- * That example did "greedy parsing" --- that is, always choosing the longest
- * match at each position. However, this interface can be (and is intended to
- * be) used for "optimal parsing" as well. It can also be used for in-between
- * strategies such as "lazy parsing" and "flexible parsing". For the best
- * performance try different match-finding algorithms and parameters to see what
- * works best for your parsing strategy, and your typical data and block sizes.
- */
-
-/*
- * TODO: this API is going to go away eventually. It has too much indirection
- * and is not flexible enough.
- */
-
-#ifndef _WIMLIB_LZ_MF_H
-#define _WIMLIB_LZ_MF_H
-
-#include "wimlib/types.h"
-
-/* When ENABLE_LZ_DEBUG is defined, we check all matches for correctness and
- * perform other validations. Use for debugging only, as it slows things down
- * significantly. */
-
-//#define ENABLE_LZ_DEBUG
-#ifdef ENABLE_LZ_DEBUG
-# include <assert.h>
-# include <string.h>
-# define LZ_ASSERT assert
-#else
-# define LZ_ASSERT(...)
-#endif
-
-struct lz_mf;
-
-/* Representation of a Lempel-Ziv match. */
-struct lz_match {
-
- /* The number of bytes matched. */
- u32 len;
-
- /* The offset back from the current position that was matched. */
- u32 offset;
-};
-
-/*
- * Specifies a match-finding algorithm.
- */
-enum lz_mf_algo {
- /*
- * Longest Common Prefix Interval Tree match-finding algorithm.
- *
- * This is a suffix array-based algorithm. It works well on medium to
- * large windows. However, due to an implementation detail, it is
- * currently limited to a maximum window size of 33554432 bytes.
- *
- * The memory usage is 12 bytes per position.
- */
- LZ_MF_LCP_INTERVAL_TREE,
-
- /*
- * Linked Suffix Array match-finding algorithm.
- *
- * This can be used on very large windows.
- *
- * The memory usage is 14 bytes per position.
- *
- * Currently, this method usually performs slightly worse than the LCP
- * interval tree algorithm. However, it can be used on windows
- * exceeding the 33554432 byte limit of the LCP interval tree algorithm.
- */
- LZ_MF_LINKED_SUFFIX_ARRAY,
-};
-
-/* Parameters for Lempel-Ziv match-finding. */
-struct lz_mf_params {
-
- /*
- * The match-finding algorithm to use. This must be one of the 'enum
- * lz_mf_algo' constants defined above.
- */
- u32 algorithm;
-
- /*
- * The maximum window size, in bytes, that shall be supported by the
- * match-finder. This is the maximum size that can be passed to
- * subsequent calls to lz_mf_load_window().
- *
- * Note: this interface is intended to be used for block compression, so
- * none of the match-finding algorithms support sliding windows. It's
- * expected that the window for LZ match-finding simply be the block of
- * data being compressed.
- *
- * Match-finders generally require an amount of memory proportional to
- * this parameter. Use lz_mf_get_needed_memory() to query the needed
- * memory size for a specific match-finding algorithm and maximum window
- * size.
- *
- * This parameter cannot be 0; there is no default value.
- *
- * Match-finding algorithms may place additional restrictions on this
- * parameter. However, currently only the LCP interval tree
- * match-finding algorithm places such a restriction (it doesn't support
- * windows larger than 33554432 bytes).
- */
- u32 max_window_size;
-
- /*
- * The minimum length, in bytes, of matches that can be produced by the
- * match-finder (by a call to lz_mf_get_matches()).
- *
- * If this parameter is not 0, it must be 2 or greater.
- *
- * If this parameter is 0, the match-finding algorithm sets it to a
- * default value. The default value will be at least 2 and at most 16.
- */
- u32 min_match_len;
-
- /*
- * The maximum length, in bytes, of matches that can be produced by the
- * match-finder (by a call to lz_mf_get_matches()).
- *
- * If this parameter is not 0, it must be greater than or equal to
- * @min_match_len, or the default value the match-finding algorithm
- * selected for @min_match_len in the case that @min_match_len was
- * specified as 0.
- *
- * If this parameter is 0, the match-finding algorithm sets it to a
- * default value. In general, the caller must be prepared to handle
- * arbitrarily long matches (up to the window size minus 1) in this
- * case.
- */
- u32 max_match_len;
-
- /*
- * This value describes the maximum amount of work that the
- * match-finding algorithm will do at each position. A typical value to
- * use is 32. Higher values result in better matches and slower
- * performance.
- *
- * If this parameter is 0, the match-finding algorithm sets it to a
- * default value.
- */
- u32 max_search_depth;
-
- /*
- * This parameter defines the maximum match length to which the full
- * algorithm will be applied. This can also be thought of as the length
- * above which the algorithm will not try to search for additional
- * matches.
- *
- * Usually, setting this parameter to a reasonable value (such as 24,
- * 32, or 48) will speed up match-finding but will not hurt the
- * compression ratio too much. This is because these settings of this
- * parameter cause the match-finder to not waste too much time examining
- * very long matches, which are already highly compressible.
- *
- * In addition, if the longest match exceeds this length, the
- * match-finding algorithm will still report its full length.
- *
- * The linked suffix array match-finding algorithm ignores this
- * parameter.
- *
- * If this parameter is 0, the match-finding algorithm sets it to a
- * default value.
- */
- u32 nice_match_len;
-};
-
-/*
- * Lempel-Ziv match-finder operations structure.
- *
- * Match-finding algorithms must fill in all members. None can be left as 0 or
- * NULL.
- *
- * Don't directly access any of the members outside of lz_mf.h and lz_mf.c.
- * Instead, use the lz_mf_*() wrappers.
- */
-struct lz_mf_ops {
- bool (*params_valid)(const struct lz_mf_params *);
-
- u64 (*get_needed_memory)(u32 max_window_size);
-
- bool (*init)(struct lz_mf *);
-
- void (*load_window)(struct lz_mf *mf, const u8 *, u32);
-
- u32 (*get_matches)(struct lz_mf *, struct lz_match *);
-
- void (*skip_positions)(struct lz_mf *, u32);
-
- void (*destroy)(struct lz_mf *);
-
- size_t struct_size;
-};
-
-/*
- * Lempel-Ziv match-finder structure.
- *
- * Match-finding algorithms must embed this structure inside a private
- * structure.
- *
- * Don't directly access any of the members outside of lz_mf.h, lz_mf.c, and
- * match-finding algorithms. Instead, use the lz_mf_*() wrappers.
- */
-struct lz_mf {
- struct lz_mf_params params;
- struct lz_mf_ops ops;
- const u8 *cur_window;
- u32 cur_window_pos;
- u32 cur_window_size;
-};
-
-extern bool
-lz_mf_params_valid(const struct lz_mf_params *params);
-
-extern u64
-lz_mf_get_needed_memory(enum lz_mf_algo algorithm, u32 max_window_size);
-
-extern struct lz_mf *
-lz_mf_alloc(const struct lz_mf_params *params);
-
-extern void
-lz_mf_load_window(struct lz_mf *mf, const u8 *window, u32 size);
-
-#ifdef ENABLE_LZ_DEBUG
-extern u32
-lz_mf_get_matches(struct lz_mf *mf, struct lz_match *matches);
-#else
-/* See non-inline definition for comment */
-static inline u32
-lz_mf_get_matches(struct lz_mf *mf, struct lz_match *matches)
-{
- return mf->ops.get_matches(mf, matches);
-}
-#endif
-
-#ifdef ENABLE_LZ_DEBUG
-extern void
-lz_mf_skip_positions(struct lz_mf *mf, u32 n);
-#else
-/* See non-inline definition for comment */
-static inline void
-lz_mf_skip_positions(struct lz_mf *mf, u32 n)
-{
- mf->ops.skip_positions(mf, n);
-}
-#endif
-
-extern void
-lz_mf_free(struct lz_mf *mf);
-
-/*
- * Returns the match-finder's current position in the window.
- *
- * The current position begins at 0. It increases by 1 when lz_mf_get_matches()
- * is called, and by 'n' when lz_mf_skip_positions() is called.
- *
- * Note: The behavior is undefined if the match-finder is advanced beyond the
- * end of the window. (If this happens in ENABLE_LZ_DEBUG mode, an assertion
- * will be triggered.)
- */
-static inline u32
-lz_mf_get_position(const struct lz_mf *mf)
-{
- return mf->cur_window_pos;
-}
-
-/*
- * Returns the number of bytes remaining in the window.
- */
-static inline u32
-lz_mf_get_bytes_remaining(const struct lz_mf *mf)
-{
- return mf->cur_window_size - mf->cur_window_pos;
-}
-
-/*
- * Returns a pointer to the current window, offset by the current position.
- * Equivalently, this returns a pointer to the byte sequence that the next call
- * to lz_mf_get_matches() will match against.
- */
-static inline const u8 *
-lz_mf_get_window_ptr(const struct lz_mf *mf)
-{
- return &mf->cur_window[mf->cur_window_pos];
-}
-
-#endif /* _WIMLIB_LZ_MF_H */
+++ /dev/null
-#include "wimlib/lz_mf.h"
-
-extern const struct lz_mf_ops lz_lcp_interval_tree_ops;
-extern const struct lz_mf_ops lz_linked_suffix_array_ops;
+++ /dev/null
-#ifndef _WIMLIB_LZ_SUFFIX_ARRAY_UTILS_H
-#define _WIMLIB_LZ_SUFFIX_ARRAY_UTILS_H
-
-#include "wimlib/types.h"
-
-#define BUILD_SA_MIN_TMP_LEN (65536 + 256)
-
-extern void
-build_SA(u32 *SA, const u8 *T, u32 n, u32 *tmp);
-
-extern void
-build_ISA(u32 *ISA, const u32 *SA, u32 n);
-
-extern void
-build_LCP(u32 *LCP, const u32 *SA, const u32 *ISA, const u8 *T, u32 n);
-
-#endif /* _WIMLIB_LZ_SUFFIX_ARRAY_UTILS_H */
#endif
#include "wimlib/divsufsort.h"
-#include "wimlib/lz_mf.h"
#include "wimlib/util.h"
+#define DIVSUFSORT_ASSERT(expr)
+
/*- Constants -*/
#define ALPHABET_SIZE 256
#define BUCKET_A_SIZE (ALPHABET_SIZE)
#define STACK_PUSH(_a, _b, _c, _d)\
do {\
- LZ_ASSERT(ssize < STACK_SIZE);\
+ DIVSUFSORT_ASSERT(ssize < STACK_SIZE);\
stack[ssize].a = (_a), stack[ssize].b = (_b),\
stack[ssize].c = (_c), stack[ssize++].d = (_d);\
} while(0)
#define STACK_PUSH5(_a, _b, _c, _d, _e)\
do {\
- LZ_ASSERT(ssize < STACK_SIZE);\
+ DIVSUFSORT_ASSERT(ssize < STACK_SIZE);\
stack[ssize].a = (_a), stack[ssize].b = (_b),\
stack[ssize].c = (_c), stack[ssize].d = (_d), stack[ssize++].e = (_e);\
} while(0)
#define STACK_POP(_a, _b, _c, _d)\
do {\
- LZ_ASSERT(0 <= ssize);\
+ DIVSUFSORT_ASSERT(0 <= ssize);\
if(ssize == 0) { return; }\
(_a) = stack[--ssize].a, (_b) = stack[ssize].b,\
(_c) = stack[ssize].c, (_d) = stack[ssize].d;\
} while(0)
#define STACK_POP5(_a, _b, _c, _d, _e)\
do {\
- LZ_ASSERT(0 <= ssize);\
+ DIVSUFSORT_ASSERT(0 <= ssize);\
if(ssize == 0) { return; }\
(_a) = stack[--ssize].a, (_b) = stack[ssize].b,\
(_c) = stack[ssize].c, (_d) = stack[ssize].d, (_e) = stack[ssize].e;\
i <= j;
--j) {
if(0 < (s = *j)) {
- LZ_ASSERT(T[s] == c1);
- LZ_ASSERT(((s + 1) < n) && (T[s] <= T[s + 1]));
- LZ_ASSERT(T[s - 1] <= T[s]);
+ DIVSUFSORT_ASSERT(T[s] == c1);
+ DIVSUFSORT_ASSERT(((s + 1) < n) && (T[s] <= T[s + 1]));
+ DIVSUFSORT_ASSERT(T[s - 1] <= T[s]);
*j = ~s;
c0 = T[--s];
if((0 < s) && (T[s - 1] > c0)) { s = ~s; }
if(0 <= c2) { BUCKET_B(c2, c1) = k - SA; }
k = SA + BUCKET_B(c2 = c0, c1);
}
- LZ_ASSERT(k < j);
+ DIVSUFSORT_ASSERT(k < j);
*k-- = s;
} else {
- LZ_ASSERT(((s == 0) && (T[s] == c1)) || (s < 0));
+ DIVSUFSORT_ASSERT(((s == 0) && (T[s] == c1)) || (s < 0));
*j = ~s;
}
}
/* Scan the suffix array from left to right. */
for(i = SA, j = SA + n; i < j; ++i) {
if(0 < (s = *i)) {
- LZ_ASSERT(T[s - 1] >= T[s]);
+ DIVSUFSORT_ASSERT(T[s - 1] >= T[s]);
c0 = T[--s];
if((s == 0) || (T[s - 1] < c0)) { s = ~s; }
if(c0 != c2) {
BUCKET_A(c2) = k - SA;
k = SA + BUCKET_A(c2 = c0);
}
- LZ_ASSERT(i < k);
+ DIVSUFSORT_ASSERT(i < k);
*k++ = s;
} else {
- LZ_ASSERT(s < 0);
+ DIVSUFSORT_ASSERT(s < 0);
*i = ~s;
}
}
/* XXX Modified from original: use provided temporary space instead of
* allocating it. */
void
-divsufsort(const u8 *T, u32 *SA, u32 n, u32 *bucket_A, u32 *bucket_B)
+divsufsort(const u8 *T, u32 *SA, u32 n, u32 *tmp)
{
+ u32 *bucket_A = tmp;
+ u32 *bucket_B = tmp + BUCKET_A_SIZE;
u32 m;
switch (n) {
--- /dev/null
+/*
+ * lcpit_matchfinder.h
+ *
+ * A match-finder for Lempel-Ziv compression based on bottom-up construction and
+ * traversal of the Longest Common Prefix (LCP) interval tree.
+ *
+ * Author: Eric Biggers
+ * Year: 2014, 2015
+ *
+ * The author dedicates this file to the public domain.
+ * You can do whatever you want with this file.
+ */
+
+#include <limits.h>
+#include <string.h>
+
+#include "wimlib/divsufsort.h"
+#include "wimlib/lcpit_matchfinder.h"
+#include "wimlib/util.h"
+
+#define LCP_BITS 6
+#define LCP_MASK ((1 << LCP_BITS) - 1)
+#define LCP_MAX LCP_MASK
+#define NORMAL_UNVISITED_TAG ((u32)1 << 31)
+#define MAX_NORMAL_BUFSIZE ((u32)1 << (31 - LCP_BITS))
+#define HUGE_UNVISITED_TAG ((u64)1 << 63)
+#define SA_and_LCP_LCP_SHIFT (32 - LCP_BITS)
+#define SA_and_LCP_POS_MASK (((u32)1 << SA_and_LCP_LCP_SHIFT) - 1)
+
+/*
+ * Include the template header to define the functions build_LCP(),
+ * build_LCPIT(), and lcpit_advance_one_byte(). There are "normal" and "huge"
+ * versions of each function. The normal versions assume that a buffer position
+ * and LCP value can be packed into a 32-bit integer, whereas the huge versions
+ * assume that 64 bits is needed.
+ *
+ * Both versions cap LCP values to 6 bits. This limits the depth of the
+ * lcp-interval tree without hurting the compression ratio too much. Matches of
+ * length 63 are sufficiently long that the compression ratio doesn't change
+ * significantly if we choose one such match over another.
+ */
+#define HUGE_MODE 1
+#include "lcpit_matchfinder_templates.h"
+#undef HUGE_MODE
+
+#define HUGE_MODE 0
+#include "lcpit_matchfinder_templates.h"
+#undef HUGE_MODE
+
+/*
+ * Calculate the number of bytes of memory needed for the LCP-interval tree
+ * matchfinder.
+ *
+ * @max_bufsize - maximum buffer size to support
+ *
+ * Returns the number of bytes required.
+ */
+u64
+lcpit_matchfinder_get_needed_memory(size_t max_bufsize)
+{
+ u64 size = 0;
+
+ /* pos_data (+1 is for prefetch) */
+ size += ((u64)max_bufsize + 1) * sizeof(u32);
+
+ /* intervals or intervals64 */
+ size += max((u64)max_bufsize, DIVSUFSORT_TMP_LEN) *
+ (max_bufsize <= MAX_NORMAL_BUFSIZE ? sizeof(u32) : sizeof(u64));
+
+ /* SA */
+ size += (u64)max_bufsize * sizeof(u32);
+
+ return size;
+}
+
+/*
+ * Initialize the LCP-interval tree matchfinder.
+ *
+ * @mf - the matchfinder structure to initialize
+ * @max_bufsize - maximum buffer size to support
+ * @min_match_len - minimum match length in bytes
+ * @nice_match_len - only consider this many bytes of each match
+ *
+ * Returns true if successfully initialized; false if out of memory.
+ */
+bool
+lcpit_matchfinder_init(struct lcpit_matchfinder *mf, size_t max_bufsize,
+ u32 min_match_len, u32 nice_match_len)
+{
+ if (lcpit_matchfinder_get_needed_memory(max_bufsize) > SIZE_MAX)
+ return false;
+
+ mf->pos_data = MALLOC((max_bufsize + 1) * sizeof(u32));
+ mf->intervals = MALLOC(max((u64)max_bufsize, DIVSUFSORT_TMP_LEN) *
+ (max_bufsize <= MAX_NORMAL_BUFSIZE ?
+ sizeof(u32) : sizeof(u64)));
+ mf->SA = MALLOC(max_bufsize * sizeof(u32));
+
+ if (!mf->pos_data || !mf->intervals || !mf->SA) {
+ lcpit_matchfinder_destroy(mf);
+ return false;
+ }
+
+ mf->min_match_len = min_match_len;
+ mf->nice_match_len = min(nice_match_len, LCP_MAX);
+ return true;
+}
+
+/*
+ * Build the suffix array SA for the specified byte array T of length n.
+ *
+ * The suffix array is a sorted array of the byte array's suffixes, represented
+ * by indices into the byte array. It can equivalently be viewed as a mapping
+ * from suffix rank to suffix position.
+ *
+ * To build the suffix array, we use libdivsufsort, which uses an
+ * induced-sorting-based algorithm. In practice, this seems to be the fastest
+ * suffix array construction algorithm currently available.
+ *
+ * References:
+ *
+ * Y. Mori. libdivsufsort, a lightweight suffix-sorting library.
+ * https://code.google.com/p/libdivsufsort/.
+ *
+ * G. Nong, S. Zhang, and W.H. Chan. 2009. Linear Suffix Array
+ * Construction by Almost Pure Induced-Sorting. Data Compression
+ * Conference, 2009. DCC '09. pp. 193 - 202.
+ *
+ * S.J. Puglisi, W.F. Smyth, and A. Turpin. 2007. A Taxonomy of Suffix
+ * Array Construction Algorithms. ACM Computing Surveys (CSUR) Volume 39
+ * Issue 2, 2007 Article No. 4.
+ */
+static void
+build_SA(u32 SA[], const u8 T[], u32 n, u32 *tmp)
+{
+ /* Note: divsufsort() needs temporary space --- one array with 256
+ * spaces and one array with 65536 spaces. The implementation of
+ * divsufsort() has been modified from the original to use the provided
+ * temporary space instead of allocating its own, since we don't want to
+ * have to deal with malloc() failures here. */
+ divsufsort(T, SA, n, tmp);
+}
+
+/*
+ * Build the inverse suffix array ISA from the suffix array SA.
+ *
+ * Whereas the suffix array is a mapping from suffix rank to suffix position,
+ * the inverse suffix array is a mapping from suffix position to suffix rank.
+ */
+static void
+build_ISA(u32 ISA[restrict], const u32 SA[restrict], u32 n)
+{
+ for (u32 r = 0; r < n; r++)
+ ISA[SA[r]] = r;
+}
+
+/*
+ * Prepare the LCP-interval tree matchfinder for a new input buffer.
+ *
+ * @mf - the initialized matchfinder structure
+ * @T - the input buffer
+ * @n - size of the input buffer in bytes. This may be at most the max_bufsize
+ * with which lcpit_matchfinder_init() was called.
+ */
+void
+lcpit_matchfinder_load_buffer(struct lcpit_matchfinder *mf, const u8 *T, u32 n)
+{
+ if (n == 0)
+ return;
+
+ build_SA(mf->SA, T, n, mf->intervals);
+ build_ISA(mf->pos_data, mf->SA, n);
+ if (n <= MAX_NORMAL_BUFSIZE) {
+ /* "Normal" sized buffer */
+
+ /* Build LCP, packing it into ->SA */
+ build_LCP_normal(mf->SA, mf->pos_data, T, n,
+ mf->min_match_len, mf->nice_match_len);
+ /* Prepare ->intervals and ->pos_data */
+ build_LCPIT_normal(mf->SA, mf->intervals, mf->pos_data, n);
+ mf->huge_mode = false;
+ } else {
+ /* "Huge" sized buffer */
+
+ /* Build LCP in the second half of ->intervals64. It may be
+ * partially overwritten in build_LCPIT_huge(), but this is okay
+ * since each LCP entry is guaranteed to be consumed before it
+ * can possibly be overwritten. */
+ build_LCP_huge(mf->intervals + n, mf->SA, mf->pos_data, T, n,
+ mf->min_match_len, mf->nice_match_len);
+ /* Prepare ->intervals64 and ->pos_data */
+ build_LCPIT_huge(mf->SA, mf->intervals + n, mf->intervals64,
+ mf->pos_data, n);
+ mf->huge_mode = true;
+ }
+ mf->cur_pos = 0; /* starting at beginning of input buffer */
+ mf->pos_data[n] = 0; /* safety entry for prefetch() overrun */
+}
+
+/*
+ * Retrieve a list of matches with the next position.
+ *
+ * The matches will be recorded in the @matches array, ordered by strictly
+ * decreasing length and strictly decreasing offset.
+ *
+ * The return value is the number of matches found and written to @matches.
+ * This can be any value in [0, nice_match_len - min_match_len + 1].
+ *
+ * If the caller attempts to advance beyond the end of the input buffer, the
+ * behavior is undefined.
+ */
+u32
+lcpit_matchfinder_get_matches(struct lcpit_matchfinder *mf,
+ struct lz_match *matches)
+{
+ if (mf->huge_mode)
+ return lcpit_advance_one_byte_huge(mf, matches, true);
+ else
+ return lcpit_advance_one_byte_normal(mf, matches, true);
+}
+
+/*
+ * Skip the next @count bytes (don't search for matches at them). @count is
+ * assumed to be > 0.
+ *
+ * If the caller attempts to advance beyond the end of the input buffer, the
+ * behavior is undefined.
+ */
+void
+lcpit_matchfinder_skip_bytes(struct lcpit_matchfinder *mf, u32 count)
+{
+ if (mf->huge_mode) {
+ do {
+ lcpit_advance_one_byte_huge(mf, NULL, false);
+ } while (--count);
+ } else {
+ do {
+ lcpit_advance_one_byte_normal(mf, NULL, false);
+ } while (--count);
+ }
+}
+
+/*
+ * Destroy an LCP-interval tree matchfinder that was previously initialized with
+ * lcpit_matchfinder_init().
+ *
+ * If the struct has been zeroed out, this has no effect.
+ */
+void
+lcpit_matchfinder_destroy(struct lcpit_matchfinder *mf)
+{
+ FREE(mf->pos_data);
+ FREE(mf->intervals);
+ FREE(mf->SA);
+ memset(mf, 0, sizeof(*mf));
+}
--- /dev/null
+/*
+ * lcpit_matchfinder_templates.h
+ *
+ * This file is included by lcpit_matchfinder.c.
+ *
+ * Author: Eric Biggers
+ * Year: 2014, 2015
+ *
+ * The author dedicates this file to the public domain.
+ * You can do whatever you want with this file.
+ */
+
+/*
+ * In normal mode, we can pack a buffer position and a LCP value into a 32-bit
+ * number. In huge mode, we can't.
+ */
+#if HUGE_MODE
+# define GET_SA_ENTRY(r) (SA[r])
+# define GET_LCP_ENTRY(r) (LCP[r])
+# define SET_LCP_ENTRY(r, val) (LCP[r] = (val))
+# define UNVISITED_TAG HUGE_UNVISITED_TAG
+#else
+# define GET_SA_ENTRY(r) (SA_and_LCP[r] & SA_and_LCP_POS_MASK)
+# define GET_LCP_ENTRY(r) (SA_and_LCP[r] >> SA_and_LCP_LCP_SHIFT)
+# define SET_LCP_ENTRY(r, val) (SA_and_LCP[r] |= (val) << SA_and_LCP_LCP_SHIFT)
+# define UNVISITED_TAG NORMAL_UNVISITED_TAG
+#endif
+
+/*
+ * Build the LCP (Longest Common Prefix) array in linear time.
+ *
+ * LCP[r] will be the length of the longest common prefix between the suffixes
+ * with positions SA[r - 1] and SA[r]. LCP[0] will be undefined.
+ *
+ * Algorithm taken from Kasai et al. (2001), but modified slightly:
+ *
+ * - For decreased memory usage and improved memory locality, pack the two
+ * logically distinct SA and LCP arrays into a single array SA_and_LCP.
+ *
+ * - With bytes there is no realistic way to reserve a unique symbol for
+ * end-of-buffer, so use explicit checks for end-of-buffer.
+ *
+ * - If a LCP value is less than the minimum match length, then store 0. This
+ * avoids having to do comparisons against the minimum match length later.
+ *
+ * - If a LCP value is greater than the "nice match length", then store the
+ * "nice match length". This caps the number of bits needed to store each
+ * LCP value, and this caps the depth of the LCP-interval tree, without
+ * usually hurting the compression ratio too much.
+ *
+ * References:
+ *
+ * Kasai et al. 2001. Linear-Time Longest-Common-Prefix Computation in
+ * Suffix Arrays and Its Applications. CPM '01 Proceedings of the 12th
+ * Annual Symposium on Combinatorial Pattern Matching pp. 181-192.
+ */
+#if HUGE_MODE
+static void
+build_LCP_huge(u32 LCP[restrict], const u32 SA[restrict], const u32 ISA[restrict],
+ const u8 T[restrict], u32 n, u32 min_lcp, u32 max_lcp)
+#else
+static void
+build_LCP_normal(u32 SA_and_LCP[restrict], const u32 ISA[restrict],
+ const u8 T[restrict], u32 n, u32 min_lcp, u32 max_lcp)
+#endif
+{
+ u32 h = 0;
+ for (u32 i = 0; i < n; i++) {
+ u32 r = ISA[i];
+ if (r > 0) {
+ u32 j = GET_SA_ENTRY(r - 1);
+ u32 lim = min(n - i, n - j);
+ while (h < lim && T[i + h] == T[j + h])
+ h++;
+ u32 stored_lcp = h;
+ if (stored_lcp < min_lcp)
+ stored_lcp = 0;
+ else if (stored_lcp > max_lcp)
+ stored_lcp = max_lcp;
+ SET_LCP_ENTRY(r, stored_lcp);
+ if (h > 0)
+ h--;
+ }
+ }
+}
+
+/*
+ * Use the suffix array accompanied with the longest-common-prefix array --- in
+ * other words, the "enhanced suffix array" --- to simulate a bottom-up
+ * traversal of the corresponding suffix tree, or equivalently the "lcp-interval
+ * tree", as described in Abouelhoda et al. (2004).
+ *
+ * While doing the traversal, create a table 'intervals' that contains data for
+ * each lcp-interval, specifically the lcp value of that interval, and the index
+ * of the superinterval.
+ *
+ * Also while doing the traversal, create a table 'pos_data' that contains a
+ * mapping from suffix index to the deepest lcp-interval containing it.
+ *
+ * The result is that we will later be able to do match-finding at a given
+ * position by looking up that position in 'pos_data' to get the deepest
+ * lcp-interval containing the corresponding suffix, then proceeding to the
+ * superintervals. See lcpit_advance_one_byte() for more details.
+ *
+ * Note: We limit the depth of the lcp-interval tree by capping the lcp at
+ * LCP_MAX. This can cause a sub-tree of intervals with lcp greater than
+ * LCP_MAX to be collapsed into a single interval with lcp LCP_MAX. This avoids
+ * degenerate cases and does not hurt match-finding very much, since if we find
+ * a match of length LCP_MAX and extend it as far as possible, that's usually
+ * good enough because that region of the input must already be highly
+ * compressible.
+ *
+ * References:
+ *
+ * M.I. Abouelhoda, S. Kurtz, E. Ohlebusch. 2004. Replacing Suffix Trees
+ * With Enhanced Suffix Arrays. Journal of Discrete Algorithms Volume 2
+ * Issue 1, March 2004, pp. 53-86.
+ *
+ * G. Chen, S.J. Puglisi, W.F. Smyth. 2008. Lempel-Ziv Factorization
+ * Using Less Time & Space. Mathematics in Computer Science June 2008,
+ * Volume 1, Issue 4, pp. 605-623.
+ *
+ * Kasai et al. Linear-Time Longest-Common-Prefix Computation in Suffix
+ * Arrays and Its Applications. 2001. CPM '01 Proceedings of the 12th
+ * Annual Symposium on Combinatorial Pattern Matching pp. 181-192.
+ */
+#if HUGE_MODE
+static void
+build_LCPIT_huge(const u32 SA[restrict], u32 LCP[], u64 intervals[],
+ u32 pos_data[restrict], u32 n)
+#else
+static void
+build_LCPIT_normal(const u32 SA_and_LCP[restrict], u32 intervals[restrict],
+ u32 pos_data[restrict], u32 n)
+#endif
+{
+ u32 next_interval_idx = 0;
+ u32 open_intervals[LCP_MAX + 1];
+ u32 *top = open_intervals;
+ u32 prev_pos = GET_SA_ENTRY(0);
+
+ /* The interval with lcp=0 covers the entire array. It remains open
+ * until the end. */
+ *top = next_interval_idx;
+ intervals[next_interval_idx] = 0;
+ next_interval_idx++;
+
+ for (u32 r = 1; r < n; r++) {
+ u32 next_pos = GET_SA_ENTRY(r);
+ u32 next_lcp = GET_LCP_ENTRY(r);
+ u32 top_lcp = intervals[*top];
+
+ if (next_lcp == top_lcp) {
+ /* continuing the deepest open interval */
+ pos_data[prev_pos] = *top;
+ } else if (next_lcp > top_lcp) {
+ /* opening a new interval */
+ intervals[next_interval_idx] = next_lcp;
+ *++top = next_interval_idx;
+ pos_data[prev_pos] = next_interval_idx;
+ next_interval_idx++;
+ } else {
+ /* closing the deepest open interval */
+ pos_data[prev_pos] = *top;
+ for (;;) {
+ u32 closed_interval_idx = *top;
+ u32 superinterval_idx = *--top;
+ u32 superinterval_lcp = intervals[superinterval_idx];
+
+ if (next_lcp == superinterval_lcp) {
+ /* continuing the superinterval */
+ intervals[closed_interval_idx] |=
+ (superinterval_idx << LCP_BITS) |
+ UNVISITED_TAG;
+ break;
+ } else if (next_lcp > superinterval_lcp) {
+ /* creating a new interval that is a
+ * superinterval of the one being
+ * closed, but still a subinterval of
+ * its superinterval */
+ intervals[next_interval_idx] = next_lcp;
+ *++top = next_interval_idx;
+ intervals[closed_interval_idx] |=
+ (next_interval_idx << LCP_BITS) |
+ UNVISITED_TAG;
+ next_interval_idx++;
+ break;
+ } else {
+ /* also closing the superinterval */
+ intervals[closed_interval_idx] |=
+ (superinterval_idx << LCP_BITS) |
+ UNVISITED_TAG;
+ }
+ }
+ }
+ prev_pos = next_pos;
+ }
+
+ /* close any still-open intervals */
+ pos_data[prev_pos] = *top;
+ while (top > open_intervals) {
+ u32 closed_interval_idx = *top;
+ u32 superinterval_idx = *--top;
+ intervals[closed_interval_idx] |=
+ (superinterval_idx << LCP_BITS) | UNVISITED_TAG;
+ }
+}
+
+/*
+ * Advance the LCP-interval tree matchfinder by one byte.
+ *
+ * If @record_matches is true, then matches are recorded in the @matches array,
+ * and the return value is the number of matches found. Otherwise, @matches is
+ * ignored and the return value is always 0.
+ */
+static inline u32
+#if HUGE_MODE
+lcpit_advance_one_byte_huge
+#else
+lcpit_advance_one_byte_normal
+#endif
+(struct lcpit_matchfinder *mf, struct lz_match * restrict matches,
+ bool record_matches)
+{
+ const u32 cur_pos = mf->cur_pos++;
+ u32 * const pos_data = mf->pos_data;
+#if HUGE_MODE
+ u64 * const intervals = mf->intervals64;
+#else
+ u32 * const intervals = mf->intervals;
+#endif
+ u32 num_matches = 0;
+ u32 lcp, next_lcp;
+ u32 interval, next_interval;
+ u32 cur_match, next_match;
+
+ /* Look up the deepest lcp-interval containing the current suffix. */
+ interval = pos_data[cur_pos];
+
+ /* Prefetch the deepest lcp-interval containing the next suffix. */
+ prefetch(&intervals[pos_data[cur_pos + 1]]);
+
+ /* Since the current position is greater than any position previously
+ * searched, set the "lcp interval of the next match" for this suffix to
+ * 0. This is the index of the root interval, and this indicates that
+ * there is no next match. */
+ pos_data[cur_pos] = 0;
+
+ /* Ascend the lcp-interval tree until we reach an lcp-interval that has
+ * already been visited. */
+
+ while (intervals[interval] & UNVISITED_TAG) {
+
+ /* Visiting this lcp-interval for the first time. Therefore,
+ * there are no matches with length equal to the lcp of this
+ * lcp-interval. */
+
+ /* Extract the LCP and superinterval reference. */
+
+ lcp = intervals[interval] & LCP_MASK;
+
+ /* If the LCP is shorter than the minimum length of matches to
+ * be produced, we're done, since the LCP will only ever get
+ * shorter from here. This also prevents ascending above the
+ * root of the lcp-interval tree, since the root is guaranteed
+ * to be a 0-interval. */
+ if (lcp == 0)
+ return 0;
+
+ next_interval = (intervals[interval] & ~UNVISITED_TAG) >> LCP_BITS;
+
+ /* Set the position of the most-recently-seen suffix within this
+ * lcp-interval. Since this is the first visitation of this
+ * lcp-interval, this is simply the current suffix.
+ *
+ * Note that this overwrites the superinterval reference which
+ * was previously included in this lcp-interval data slot.
+ * Further visitations of this lcp-interval will detect that it
+ * is already visited and will follow the chain of
+ * most-recently-seen suffixes rather than ascend the tree
+ * directly. */
+ intervals[interval] = (cur_pos << LCP_BITS) | lcp;
+
+ /* Ascend to the superinterval of this lcp-interval. */
+ interval = next_interval;
+ }
+
+ /* We've already visited the current lcp-interval. */
+
+ /* Extract the LCP of this lcp-interval. */
+ lcp = intervals[interval] & LCP_MASK;
+
+ /* Extract the current match for this lcp-interval. This usually is the
+ * most-recently-seen suffix within this lcp-interval, but it may be
+ * outdated. */
+ cur_match = intervals[interval] >> LCP_BITS;
+
+ for (;;) {
+ /* If the LCP is shorter than the minimum length of matches to
+ * be produced, we're done, since the LCP will only ever get
+ * shorter from here. This also prevents ascending above the
+ * root of the lcp-interval tree, since the root is guaranteed
+ * to be a 0-interval. */
+ if (lcp == 0)
+ break;
+
+ /* Advance the current match until the lcp of the *next* match
+ * is lower than the current lcp. When this is true we know
+ * that the current match is up to date (lowest offset /
+ * greatest position for that lcp). */
+
+ next_match = cur_match;
+ do {
+ next_interval = pos_data[next_match];
+ next_lcp = intervals[next_interval] & LCP_MASK;
+ cur_match = next_match;
+ next_match = intervals[next_interval] >> LCP_BITS;
+ } while (next_lcp >= lcp);
+
+ /* Link the current position into the match chain, discarding
+ * any skipped matches. */
+ intervals[interval] = (cur_pos << LCP_BITS) | lcp;
+ pos_data[cur_match] = interval;
+
+ if (record_matches) {
+ /* Record the match. */
+ matches[num_matches].length = lcp;
+ matches[num_matches].offset = cur_pos - cur_match;
+ num_matches++;
+ }
+
+ /* Advance to the next match. */
+ interval = next_interval;
+ lcp = next_lcp;
+ cur_match = next_match;
+ }
+ return num_matches;
+}
+
+#undef GET_SA_ENTRY
+#undef GET_LCP_ENTRY
+#undef SET_LCP_ENTRY
+#undef UNVISITED_TAG
+++ /dev/null
-/*
- * lz_lcp_interval_tree.c
- *
- * A match-finder for Lempel-Ziv compression based on bottom-up construction and
- * traversal of the Longest Common Prefix (LCP) interval tree.
- *
- * Copyright (c) 2014 Eric Biggers. All rights reserved.
- *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions
- * are met:
- *
- * 1. Redistributions of source code must retain the above copyright
- * notice, this list of conditions and the following disclaimer.
- *
- * 2. Redistributions in binary form must reproduce the above copyright
- * notice, this list of conditions and the following disclaimer in the
- * documentation and/or other materials provided with the distribution.
- *
- * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS "AS IS" AND
- * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
- * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
- * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE
- * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
- * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
- * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
- * BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
- * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
- * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
- * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
- */
-
-#ifdef HAVE_CONFIG_H
-# include "config.h"
-#endif
-
-#include "wimlib/lz_mf.h"
-#include "wimlib/lz_suffix_array_utils.h"
-#include "wimlib/util.h"
-
-/*
- * To save space, we pack lcp (longest common prefix) and position values into
- * 32-bit integers. Therefore, we must divide the 32 bits into lcp and position
- * bits. 6 lcp bits seems to be a good value, since matches of length 64 are
- * sufficiently long so that the compression ratio isn't hurt much by choosing
- * one such match over another. We also use 1 bit to mark intervals as "not yet
- * visited". This leaves 25 bits, which when used for position results in a
- * maximum window size of 33554432 bytes.
- */
-#define LZ_LCPIT_LCP_BITS 6
-#define LZ_LCPIT_LCP_MASK ((1 << LZ_LCPIT_LCP_BITS) - 1)
-#define LZ_LCPIT_LCP_MAX LZ_LCPIT_LCP_MASK
-#define LZ_LCPIT_POS_BITS (32 - 1 - LZ_LCPIT_LCP_BITS)
-#define LZ_LCPIT_MAX_WINDOW_SIZE (1UL << LZ_LCPIT_POS_BITS)
-
-#define SA_and_LCP_LCP_SHIFT (32 - LZ_LCPIT_LCP_BITS)
-#define SA_and_LCP_POS_MASK (((u32)1 << SA_and_LCP_LCP_SHIFT) - 1)
-
-struct lz_lcpit {
- struct lz_mf base;
-
- u32 *mem;
-
- /* Mapping: lcp-interval index => lcp-interval data
- *
- * Initially, the lcp-interval data for an lcp-interval contains that
- * interval's lcp and superinterval index.
- *
- * After a lcp-interval is visited during match-finding, its
- * lcp-interval data contains that interval's lcp and the position of
- * the next suffix to consider as a match when matching against that
- * lcp-interval. */
- u32 *intervals;
-
- /* Mapping: suffix index ("window position") => lcp-interval index */
- u32 *pos_data;
-};
-
-/*
- * Build the LCP (Longest Common Prefix) array in linear time.
- *
- * LCP[r] will be the length of the longest common prefix between the suffixes
- * with positions SA[r - 1] and SA[r]. LCP[0] will be undefined.
- *
- * Algorithm taken from Kasai et al. (2001), but modified slightly:
- *
- * - For decreased memory usage and improved memory locality, pack the two
- * logically distinct SA and LCP arrays into a single array SA_and_LCP.
- *
- * - With bytes there is no realistic way to reserve a unique symbol for
- * end-of-buffer, so use explicit checks for end-of-buffer.
- *
- * - If a LCP value is less than the minimum match length, then store 0. This
- * avoids having to do comparisons against the minimum match length later.
- *
- * - If a LCP value is greater than the "nice match length", then store the
- * "nice match length". This caps the number of bits needed to store each
- * LCP value, and this caps the depth of the LCP-interval tree, without
- * usually hurting the compression ratio too much.
- *
- * References:
- *
- * Kasai et al. 2001. Linear-Time Longest-Common-Prefix Computation in
- * Suffix Arrays and Its Applications. CPM '01 Proceedings of the 12th
- * Annual Symposium on Combinatorial Pattern Matching pp. 181-192.
- */
-static void
-build_LCP_packed(u32 * const restrict SA_and_LCP, const u32 * const restrict ISA,
- const u8 * const restrict T, const u32 n,
- const u32 min_lcp, const u32 max_lcp)
-{
- u32 h, i, r, j, lim, stored_lcp;
-
- h = 0;
- for (i = 0; i < n; i++) {
- r = ISA[i];
- if (r > 0) {
- j = SA_and_LCP[r - 1] & SA_and_LCP_POS_MASK;
- lim = min(n - i, n - j);
- while (h < lim && T[i + h] == T[j + h])
- h++;
- stored_lcp = h;
- if (stored_lcp < min_lcp)
- stored_lcp = 0;
- else if (stored_lcp > max_lcp)
- stored_lcp = max_lcp;
- SA_and_LCP[r] |= stored_lcp << SA_and_LCP_LCP_SHIFT;
- if (h > 0)
- h--;
- }
- }
-}
-
-/*
- * Use the suffix array accompanied with the longest-common-prefix array --- in
- * other words, the "enhanced suffix array" --- to simulate a bottom-up
- * traversal of the corresponding suffix tree, or equivalently the "lcp-interval
- * tree", as described in Abouelhoda et al. (2004).
- *
- * While doing the traversal, create a table 'intervals' that contains data for
- * each lcp-interval, specifically the lcp value of that interval, and the index
- * of the superinterval.
- *
- * Also while doing the traversal, create a table 'pos_data' that contains a
- * mapping from suffix index to the deepest lcp-interval containing it.
- *
- * The result is that we will later be able to do match-finding at a given
- * position by looking up that position in 'pos_data' to get the deepest
- * lcp-interval containing the corresponding suffix, then proceeding to the
- * superintervals. See lz_lcpit_get_matches() for more details.
- *
- * Note: We limit the depth of the lcp-interval tree by capping the lcp at
- * LZ_LCPIT_LCP_MAX. This can cause a sub-tree of intervals with lcp greater
- * than LZ_LCPIT_LCP_MAX to be collapsed into a single interval with lcp
- * LZ_LCPIT_LCP_MAX. This avoids degenerate cases and does not hurt
- * match-finding very much, since if we find a match of length LZ_LCPIT_LCP_MAX
- * and extend it as far as possible, that's usually good enough because that
- * region of the input must already be highly compressible.
- *
- * References:
- *
- * M.I. Abouelhoda, S. Kurtz, E. Ohlebusch. 2004. Replacing Suffix Trees
- * With Enhanced Suffix Arrays. Journal of Discrete Algorithms Volume 2
- * Issue 1, March 2004, pp. 53-86.
- *
- * G. Chen, S.J. Puglisi, W.F. Smyth. 2008. Lempel-Ziv Factorization
- * Using Less Time & Space. Mathematics in Computer Science June 2008,
- * Volume 1, Issue 4, pp. 605-623.
- *
- * Kasai et al. Linear-Time Longest-Common-Prefix Computation in Suffix
- * Arrays and Its Applications. 2001. CPM '01 Proceedings of the 12th
- * Annual Symposium on Combinatorial Pattern Matching pp. 181-192.
- */
-static void
-build_LCPIT(const u32 * const restrict SA_and_LCP,
- u32 * const restrict intervals, u32 * const restrict pos_data,
- const u32 n)
-{
- u32 next_interval_idx = 0;
- u32 open_intervals[LZ_LCPIT_LCP_MAX + 1];
- u32 *top = open_intervals;
- u32 prev_pos = SA_and_LCP[0] & SA_and_LCP_POS_MASK;
-
- /* The interval with lcp=0 covers the entire array. It remains open
- * until the end. */
- *top = next_interval_idx;
- intervals[next_interval_idx] = 0;
- next_interval_idx++;
-
- for (u32 r = 1; r < n; r++) {
- u32 next_pos = SA_and_LCP[r] & SA_and_LCP_POS_MASK;
- u32 next_lcp = SA_and_LCP[r] >> SA_and_LCP_LCP_SHIFT;
- u32 top_lcp = intervals[*top];
-
- if (next_lcp == top_lcp) {
- /* continuing the deepest open interval */
- pos_data[prev_pos] = *top;
- } else if (next_lcp > top_lcp) {
- /* opening a new interval */
- intervals[next_interval_idx] = next_lcp;
- *++top = next_interval_idx;
- pos_data[prev_pos] = next_interval_idx;
- next_interval_idx++;
- } else {
- /* closing the deepest open interval */
- pos_data[prev_pos] = *top;
- for (;;) {
- u32 closed_interval_idx = *top;
- u32 superinterval_idx = *--top;
- u32 superinterval_lcp = intervals[superinterval_idx];
-
- if (next_lcp == superinterval_lcp) {
- /* continuing the superinterval */
- intervals[closed_interval_idx] |=
- (superinterval_idx << LZ_LCPIT_LCP_BITS) |
- 0x80000000;
- break;
- } else if (next_lcp > superinterval_lcp) {
- /* creating a new interval that is a
- * superinterval of the one being
- * closed, but still a subinterval of
- * its superinterval */
- intervals[next_interval_idx] = next_lcp;
- *++top = next_interval_idx;
- intervals[closed_interval_idx] |=
- (next_interval_idx << LZ_LCPIT_LCP_BITS) |
- 0x80000000;
- next_interval_idx++;
- break;
- } else {
- /* also closing the superinterval */
- intervals[closed_interval_idx] |=
- (superinterval_idx << LZ_LCPIT_LCP_BITS) |
- 0x80000000;
- }
- }
- }
- prev_pos = next_pos;
- }
-
- /* close any still-open intervals */
- pos_data[prev_pos] = *top;
- while (top > open_intervals) {
- u32 closed_interval_idx = *top;
- u32 superinterval_idx = *--top;
- intervals[closed_interval_idx] |=
- (superinterval_idx << LZ_LCPIT_LCP_BITS) | 0x80000000;
- }
-}
-
-static void
-lz_lcpit_set_default_params(struct lz_mf_params *params)
-{
- if (params->min_match_len == 0)
- params->min_match_len = 2;
-
- if (params->max_match_len == 0)
- params->max_match_len = UINT32_MAX;
-
- if (params->max_search_depth == 0)
- params->max_search_depth = 32;
-
- params->max_search_depth = DIV_ROUND_UP(params->max_search_depth, 8);
-
- if (params->nice_match_len == 0)
- params->nice_match_len = LZ_LCPIT_LCP_MAX;
-
- if (params->nice_match_len < params->min_match_len)
- params->nice_match_len = params->min_match_len;
-
- if (params->nice_match_len > params->max_match_len)
- params->nice_match_len = params->max_match_len;
-
- if (params->nice_match_len > LZ_LCPIT_LCP_MAX)
- params->nice_match_len = LZ_LCPIT_LCP_MAX;
-}
-
-static bool
-lz_lcpit_params_valid(const struct lz_mf_params *params)
-{
- return params->max_window_size <= LZ_LCPIT_MAX_WINDOW_SIZE;
-}
-
-static u64
-lz_lcpit_get_needed_memory(u32 max_window_size)
-{
- return sizeof(u32) * (max_window_size +
- max(BUILD_SA_MIN_TMP_LEN,
- 2 * (u64)max_window_size));
-}
-
-static bool
-lz_lcpit_init(struct lz_mf *_mf)
-{
- struct lz_lcpit *mf = (struct lz_lcpit *)_mf;
-
- lz_lcpit_set_default_params(&mf->base.params);
-
- mf->mem = MALLOC(lz_lcpit_get_needed_memory(mf->base.params.max_window_size));
- return (mf->mem != NULL);
-}
-
-static void
-lz_lcpit_load_window(struct lz_mf *_mf, const u8 T[], u32 n)
-{
- struct lz_lcpit *mf = (struct lz_lcpit *)_mf;
-
- build_SA(&mf->mem[0 * n], T, n, &mf->mem[1 * n]);
- build_ISA(&mf->mem[2 * n], &mf->mem[0 * n], n);
- build_LCP_packed(&mf->mem[0 * n], &mf->mem[2 * n], T, n,
- mf->base.params.min_match_len,
- mf->base.params.nice_match_len);
- build_LCPIT(&mf->mem[0 * n], &mf->mem[1 * n], &mf->mem[2 * n], n);
- mf->intervals = &mf->mem[1 * n];
- mf->pos_data = &mf->mem[2 * n];
-}
-
-static u32
-lz_lcpit_get_matches(struct lz_mf *_mf, struct lz_match matches[])
-{
- struct lz_lcpit *mf = (struct lz_lcpit *)_mf;
- const u32 cur_pos = mf->base.cur_window_pos;
- u32 * const pos_data = mf->pos_data;
- u32 * const intervals = mf->intervals;
- u32 num_matches = 0;
- u32 lcp, next_lcp;
- u32 interval, next_interval;
- u32 cur_match, next_match;
-
- /* Look up the deepest lcp-interval containing the current suffix. */
- interval = pos_data[cur_pos];
-
- /* Since the current position is greater than any position previously
- * searched, set the "lcp interval of the next match" for this suffix to
- * 0. This is the index of the root interval, and this indicates that
- * there is no next match. */
- pos_data[cur_pos] = 0;
-
- /* Ascend the lcp-interval tree until we reach an lcp-interval that has
- * already been visited. */
-
- while (intervals[interval] & 0x80000000) {
-
- /* Visiting this lcp-interval for the first time. Therefore,
- * there are no Lempel-Ziv matches with length equal to the lcp
- * of this lcp-interval. */
-
- /* Extract the LCP and superinterval reference. */
-
- lcp = intervals[interval] & LZ_LCPIT_LCP_MASK;
-
- next_interval = (intervals[interval] & ~0x80000000)
- >> LZ_LCPIT_LCP_BITS;
-
- /* If the LCP is shorter than the minimum length of matches to
- * be produced, we're done, since the LCP will only ever get
- * shorter from here. This also prevents ascending above the
- * root of the lcp-interval tree, since the root is guaranteed
- * to be a 0-interval. */
- if (lcp == 0)
- goto out;
-
- /* Set the position of the most-recently-seen suffix within this
- * lcp-interval. Since this is the first visitation of this
- * lcp-interval, this is simply the current suffix.
- *
- * Note that this overwrites the superinterval reference which
- * was previously included in this lcp-interval data slot.
- * Further visitations of this lcp-interval will detect that it
- * is already visited and will follow the chain of
- * most-recently-seen suffixes rather than ascend the tree
- * directly. */
- intervals[interval] = (cur_pos << LZ_LCPIT_LCP_BITS) | lcp;
-
- /* Ascend to the superinterval of this lcp-interval. */
- interval = next_interval;
- }
-
- /* We've already visited the current lcp-interval. */
-
- /* Extract the LCP of this lcp-interval. */
- lcp = intervals[interval] & LZ_LCPIT_LCP_MASK;
-
- /* Extract the current match for this lcp-interval. This usually is the
- * most-recently-seen suffix within this lcp-interval, but it may be
- * outdated. */
- cur_match = intervals[interval] >> LZ_LCPIT_LCP_BITS;
-
- for (;;) {
- /* If the LCP is shorter than the minimum length of matches to
- * be produced, we're done, since the LCP will only ever get
- * shorter from here. This also prevents ascending above the
- * root of the lcp-interval tree, since the root is guaranteed
- * to be a 0-interval. */
- if (lcp == 0)
- break;
-
- /* Advance the current match until the lcp of the *next* match
- * is lower than the current lcp. When this is true we know
- * that the current match is up to date (lowest offset /
- * greatest position for that lcp). */
-
- next_match = cur_match;
- do {
- next_interval = pos_data[next_match];
- next_lcp = intervals[next_interval] & LZ_LCPIT_LCP_MASK;
- cur_match = next_match;
- next_match = intervals[next_interval] >> LZ_LCPIT_LCP_BITS;
- } while (next_lcp >= lcp);
-
- /* Link the current position into the match chain, discarding
- * any skipped matches. */
- intervals[interval] = (cur_pos << LZ_LCPIT_LCP_BITS) | lcp;
- pos_data[cur_match] = interval;
-
- /* Record the match. */
- matches[num_matches++] = (struct lz_match) {
- .len = lcp,
- .offset = cur_pos - cur_match,
- };
-
- /* Bound the number of matches per position. */
- if (num_matches >= mf->base.params.max_search_depth)
- break;
-
- /* Advance to the next match. */
- interval = next_interval;
- lcp = next_lcp;
- cur_match = next_match;
- }
-
- /* If the length of the longest match is equal to the lcp limit, it may
- * have been truncated. Try extending it up to the maximum match
- * length. */
- if (num_matches && matches[0].len == mf->base.params.nice_match_len) {
- const u8 * const strptr = lz_mf_get_window_ptr(&mf->base);
- const u8 * const matchptr = strptr - matches[0].offset;
- const u32 len_limit = min(lz_mf_get_bytes_remaining(&mf->base),
- mf->base.params.max_match_len);
- u32 len;
-
- len = matches[0].len;
- while (len < len_limit && strptr[len] == matchptr[len])
- len++;
- matches[0].len = len;
- }
-
- for (u32 i = 0; i < num_matches / 2; i++)
- swap(matches[i], matches[num_matches - 1 - i]);
-out:
- mf->base.cur_window_pos++;
- return num_matches;
-}
-
-/* Slightly simplified version of lz_lcpit_get_matches() for updating the data
- * structures when we don't actually need matches at the current position. See
- * lz_lcpit_get_matches() for explanatory comments. */
-static void
-lz_lcpit_skip_position(struct lz_lcpit *mf)
-{
- const u32 cur_pos = mf->base.cur_window_pos++;
- u32 * const pos_data = mf->pos_data;
- u32 * const intervals = mf->intervals;
- u32 lcp, next_lcp;
- u32 interval, next_interval;
- u32 cur_match, next_match;
-
- interval = pos_data[cur_pos];
- pos_data[cur_pos] = 0;
- while (intervals[interval] & 0x80000000) {
- lcp = intervals[interval] & LZ_LCPIT_LCP_MASK;
- next_interval = (intervals[interval] & ~0x80000000)
- >> LZ_LCPIT_LCP_BITS;
- if (lcp == 0)
- return;
- intervals[interval] = (cur_pos << LZ_LCPIT_LCP_BITS) | lcp;
- interval = next_interval;
- }
- lcp = intervals[interval] & LZ_LCPIT_LCP_MASK;
- cur_match = intervals[interval] >> LZ_LCPIT_LCP_BITS;
- while (lcp != 0) {
- next_match = cur_match;
- do {
- next_interval = pos_data[next_match];
- next_lcp = intervals[next_interval] & LZ_LCPIT_LCP_MASK;
- cur_match = next_match;
- next_match = intervals[next_interval] >> LZ_LCPIT_LCP_BITS;
- } while (next_lcp >= lcp);
- intervals[interval] = (cur_pos << LZ_LCPIT_LCP_BITS) | lcp;
- pos_data[cur_match] = interval;
- interval = next_interval;
- lcp = next_lcp;
- cur_match = next_match;
- }
-}
-
-static void
-lz_lcpit_skip_positions(struct lz_mf *_mf, u32 n)
-{
- struct lz_lcpit *mf = (struct lz_lcpit *)_mf;
-
- do {
- lz_lcpit_skip_position(mf);
- } while (--n);
-}
-
-static void
-lz_lcpit_destroy(struct lz_mf *_mf)
-{
- struct lz_lcpit *mf = (struct lz_lcpit *)_mf;
-
- FREE(mf->mem);
-}
-
-const struct lz_mf_ops lz_lcp_interval_tree_ops = {
- .params_valid = lz_lcpit_params_valid,
- .get_needed_memory = lz_lcpit_get_needed_memory,
- .init = lz_lcpit_init,
- .load_window = lz_lcpit_load_window,
- .get_matches = lz_lcpit_get_matches,
- .skip_positions = lz_lcpit_skip_positions,
- .destroy = lz_lcpit_destroy,
- .struct_size = sizeof(struct lz_lcpit),
-};
+++ /dev/null
-/*
- * lz_linked_suffix_array.c
- *
- * Linked suffix array match-finder for Lempel-Ziv compression.
- *
- * Copyright (c) 2013, 2014 Eric Biggers. All rights reserved.
- *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions
- * are met:
- *
- * 1. Redistributions of source code must retain the above copyright
- * notice, this list of conditions and the following disclaimer.
- *
- * 2. Redistributions in binary form must reproduce the above copyright
- * notice, this list of conditions and the following disclaimer in the
- * documentation and/or other materials provided with the distribution.
- *
- * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS "AS IS" AND
- * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
- * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
- * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE
- * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
- * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
- * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
- * BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
- * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
- * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
- * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
- */
-
-#ifdef HAVE_CONFIG_H
-# include "config.h"
-#endif
-
-#include "wimlib/lz_mf.h"
-#include "wimlib/lz_suffix_array_utils.h"
-#include "wimlib/util.h"
-
-struct salink;
-
-/* Length type --- must be an unsigned type large enough to hold the maximum
- * match length. */
-typedef u16 lz_lsa_len_t;
-
-/* Type of distances in suffix array links. A larger type would allow skipping
- * irrelevant suffixes more quickly, which is especially helpful towards the
- * start of the window. However, even a single byte allows skipping 255 at a
- * time, which where it matters is already a big improvement over the
- * alternative of searching the suffixes consecutively. */
-typedef u8 lz_lsa_delta_t;
-
-#define LZ_LSA_LEN_MAX ((lz_lsa_len_t)~0UL)
-#define LZ_LSA_POS_MAX ((u32)~0UL)
-#define LZ_LSA_DELTA_MAX ((lz_lsa_delta_t)~0UL)
-
-/* State of the linked suffix array match-finder. */
-struct lz_lsa {
-
- struct lz_mf base;
-
- /* Suffix array for the current window.
- * This is a mapping from suffix rank to suffix position. */
- u32 *SA;
-
- /* Inverse suffix array for the current window.
- * This is a mapping from suffix position to suffix rank.
- * If 0 <= r < window_size, then ISA[SA[r]] == r. */
- u32 *ISA;
-
- /* Suffix array links.
- *
- * During a linear scan of the input string to find matches, this array
- * used to keep track of which rank suffixes in the suffix array appear
- * before the current position. Instead of searching in the original
- * suffix array, scans for matches at a given position traverse a linked
- * list containing (usually) only suffixes that appear before that
- * position. */
- struct salink *salink;
-};
-
-/* Suffix array link. An array of these structures, one per suffix rank, is
- * used as a replacement for the raw LCP (Longest Common Prefix) array to allow
- * skipping over suffixes that appear later in the window and hence cannot be
- * used as LZ77 matches. */
-struct salink {
- union {
- /* Temporary fields used while this structure is being
- * initialized.
- *
- * Note: we want the entire `struct salink' to be only 6 bytes,
- * even though this makes "next_initial" unaligned. */
- struct {
- u32 next_initial;
- lz_lsa_len_t lcpnext_initial;
- } _packed_attribute;
-
- struct {
- /* Intially, the length, in bytes, of the longest common
- * prefix (LCP) between the suffix having this rank and
- * the suffix with the smallest larger rank that
- * starts earlier in the window than the suffix having
- * this rank. If no such suffix exists, this will be 0.
- *
- * Later, during match-finding, after the corresponding
- * suffix has entered the LZ77 dictionary, this value
- * may be updated by lz_lsa_update_salink() to refer
- * instead to a lexicographically closer (but still
- * larger) suffix that begins at a later position that
- * has entered the LZ77 dictionary. */
- lz_lsa_len_t lcpnext;
-
- /* Initially, the length, in bytes, of the longest
- * common prefix (LCP) between the suffix having this
- * rank and the suffix with the largest smaller rank
- * that starts earlier in the window than the suffix
- * having this rank. If no such suffix exists, this
- * will be 0.
- *
- * Later, during match-finding, after the corresponding
- * suffix has entered the LZ77 dictionary, this value
- * may be updated by lz_lsa_update_salink() to refer
- * instead to a lexicographically closer (but still
- * smaller) suffix that begins at a later position that
- * has entered the LZ77 dictionary. */
- lz_lsa_len_t lcpprev;
-
- /* Distance to the suffix referred to in the description
- * of "lcpnext" above, but capped to a maximum value to
- * save memory; or, 0 if no such suffix exists. If the
- * true distance was truncated, this will give the
- * distance to the rank of a suffix that is
- * lexicographically closer to the current suffix than
- * the desired suffix, but appears *later* in the window
- * and hence cannot be used as the basis for an LZ77
- * match. */
- lz_lsa_delta_t dist_to_next;
-
- /* Distance to the suffix referred to in the description
- * of "lcpprev" above, but capped to a maximum value to
- * save memory; or, 0 if no such suffix exists. If the
- * true distance was truncated, this will give the
- * distance to the rank of a suffix that is
- * lexicographically closer to the current suffix than
- * the desired suffix, but appears *later* in the window
- * and hence cannot be used as the basis for an LZ77
- * match. */
- lz_lsa_delta_t dist_to_prev;
- };
- };
-};
-
-/* Initialize the SA link array in linear time.
- *
- * This is similar to computing the LPF (Longest Previous Factor) array, which
- * is addressed in several papers. In particular the algorithms below are based
- * on Crochemore et al. 2009: "LPF computation revisited". However, this
- * match-finder does not actually compute or use the LPF array per se. Rather,
- * this function sets up some information necessary to compute the LPF array,
- * but later lz_lsa_get_matches() actually uses this information to search
- * the suffix array directly and can keep searching beyond the first (longest)
- * match whose length would be placed in the LPF array. This difference from
- * the theoretical work is necessary because in many real compression formats
- * matches take variable numbers of bits to encode, so a decent parser needs to
- * consider more than just the longest match with unspecified offset.
- *
- * Note: We cap the lcpprev and lcpnext values to the maximum match length so
- * that the match-finder need not worry about it later, in the inner loop.
- *
- * Note: the LCP array is one of the inputs to this function, but it is used as
- * temporary space and therefore will be invalidated.
- */
-static void
-init_salink(struct salink link[restrict], u32 LCP[restrict],
- const u32 SA[restrict], const u8 T[restrict], u32 n,
- lz_lsa_len_t min_match_len, lz_lsa_len_t max_match_len)
-{
- /* Calculate salink.dist_to_next and salink.lcpnext.
- *
- * Pass 1 calculates, for each suffix rank, the corresponding
- * "next_initial" value which is the smallest larger rank that
- * corresponds to a suffix starting earlier in the string. It also
- * calculates "lcpnext_initial", which is the longest common prefix with
- * that suffix, although to eliminate checks in lz_lsa_get_matches(),
- * "lcpnext_initial" is set to 0 if it's less than the minimum match
- * length or set to the maximum match length if it's greater than the
- * maximum match length.
- *
- * Pass 2 translates each absolute "next_initial", a 4-byte value, into
- * a relative "dist_to_next", a 1-byte value. This is done to save
- * memory. In the case that the exact relative distance cannot be
- * encoded in 1 byte, it is capped to 255. This is valid as long as
- * lz_lsa_get_matches() validates each position before using it.
- * Note that "lcpnext" need not be updated in this case because it will
- * not be used until the actual next rank has been found anyway.
- */
- link[n - 1].next_initial = LZ_LSA_POS_MAX;
- link[n - 1].lcpnext_initial = 0;
- for (u32 r = n - 2; r != LZ_LSA_POS_MAX; r--) {
- u32 t = r + 1;
- u32 l = LCP[t];
- while (t != LZ_LSA_POS_MAX && SA[t] > SA[r]) {
- l = min(l, link[t].lcpnext_initial);
- t = link[t].next_initial;
- }
- link[r].next_initial = t;
-
- if (l < min_match_len)
- l = 0;
- else if (l > max_match_len)
- l = max_match_len;
- link[r].lcpnext_initial = l;
- }
- for (u32 r = 0; r < n; r++) {
- u32 next;
- lz_lsa_len_t l;
- lz_lsa_delta_t dist_to_next;
-
- next = link[r].next_initial;
- l = link[r].lcpnext_initial;
-
- if (next == LZ_LSA_POS_MAX)
- dist_to_next = 0;
- else if (next - r <= LZ_LSA_DELTA_MAX)
- dist_to_next = next - r;
- else
- dist_to_next = LZ_LSA_DELTA_MAX;
-
- link[r].lcpnext = l;
- link[r].dist_to_next = dist_to_next;
- }
-
- /* Calculate salink.dist_to_prev and salink.lcpprev.
- *
- * This is analgous to dist_to_next and lcpnext as described above, but
- * in the other direction. That is, here we're interested in, for each
- * rank, the largest smaller rank that corresponds to a suffix starting
- * earlier in the string.
- *
- * To save memory we don't have a "prev_initial" field, but rather store
- * those values in the LCP array. */
- LCP[0] = LZ_LSA_POS_MAX;
- link[0].lcpprev = 0;
- for (u32 r = 1; r < n; r++) {
- u32 t = r - 1;
- u32 l = LCP[r];
- while (t != LZ_LSA_POS_MAX && SA[t] > SA[r]) {
- l = min(l, link[t].lcpprev);
- t = LCP[t];
- }
- LCP[r] = t;
-
- if (l < min_match_len)
- l = 0;
- else if (l > max_match_len)
- l = max_match_len;
-
- link[r].lcpprev = l;
- }
- for (u32 r = 0; r < n; r++) {
-
- u32 prev = LCP[r];
-
- if (prev == LZ_LSA_POS_MAX)
- link[r].dist_to_prev = 0;
- else if (r - prev <= LZ_LSA_DELTA_MAX)
- link[r].dist_to_prev = r - prev;
- else
- link[r].dist_to_prev = LZ_LSA_DELTA_MAX;
- }
-}
-
-/* If ENABLE_LZ_DEBUG is defined, verify the values computed by init_salink().
- *
- * WARNING: this is for debug use only as it does not necessarily run in linear
- * time!!! */
-static void
-verify_salink(const struct salink link[], const u32 SA[], const u8 T[], u32 n,
- lz_lsa_len_t min_match_len, lz_lsa_len_t max_match_len)
-{
-#ifdef ENABLE_LZ_DEBUG
- for (u32 r = 0; r < n; r++) {
- for (u32 prev = r; ; ) {
- if (prev == 0) {
- LZ_ASSERT(link[r].dist_to_prev == 0);
- LZ_ASSERT(link[r].lcpprev == 0);
- break;
- }
-
- prev--;
-
- if (SA[prev] < SA[r]) {
- LZ_ASSERT(link[r].dist_to_prev == min(r - prev, LZ_LSA_DELTA_MAX));
-
- u32 lcpprev;
- for (lcpprev = 0;
- lcpprev < min(n - SA[prev], n - SA[r]) &&
- T[SA[prev] + lcpprev] == T[SA[r] + lcpprev];
- lcpprev++)
- ;
- if (lcpprev < min_match_len)
- lcpprev = 0;
- else if (lcpprev > max_match_len)
- lcpprev = max_match_len;
-
- LZ_ASSERT(lcpprev == link[r].lcpprev);
- break;
- }
- }
-
- for (u32 next = r; ; ) {
- if (next == n - 1) {
- LZ_ASSERT(link[r].dist_to_next == 0);
- LZ_ASSERT(link[r].lcpnext == 0);
- break;
- }
-
- next++;
-
- if (SA[next] < SA[r]) {
- LZ_ASSERT(link[r].dist_to_next == min(next - r, LZ_LSA_DELTA_MAX));
-
- u32 lcpnext;
- for (lcpnext = 0;
- lcpnext < min(n - SA[next], n - SA[r]) &&
- T[SA[next] + lcpnext] == T[SA[r] + lcpnext];
- lcpnext++)
- ;
- if (lcpnext < min_match_len)
- lcpnext = 0;
- else if (lcpnext > max_match_len)
- lcpnext = max_match_len;
-
- LZ_ASSERT(lcpnext == link[r].lcpnext);
- break;
- }
- }
- }
-#endif
-}
-
-static inline void
-lz_lsa_update_salink(const u32 r, struct salink link[])
-{
- const u32 next = r + link[r].dist_to_next;
- const u32 prev = r - link[r].dist_to_prev;
-
- if (next != r && link[r].dist_to_next < link[next].dist_to_prev) {
- link[next].dist_to_prev = link[r].dist_to_next;
- link[next].lcpprev = link[r].lcpnext;
- }
-
- if (prev != r && link[r].dist_to_prev < link[prev].dist_to_next) {
- link[prev].dist_to_next = link[r].dist_to_prev;
- link[prev].lcpnext = link[r].lcpprev;
- }
-}
-
-static void
-lz_lsa_set_default_params(struct lz_mf_params *params)
-{
- if (params->min_match_len == 0)
- params->min_match_len = 2;
-
- if (params->max_match_len == 0)
- params->max_match_len = UINT32_MAX;
-
- if (params->max_match_len > LZ_LSA_LEN_MAX)
- params->max_match_len = LZ_LSA_LEN_MAX;
-
- if (params->max_search_depth == 0)
- params->max_search_depth = 32;
-
- /* Scale max_search_depth down since this algorithm finds the longest
- * matches first. */
- params->max_search_depth = DIV_ROUND_UP(params->max_search_depth, 5);
-}
-
-static u64
-lz_lsa_get_needed_memory(u32 max_window_size)
-{
- u64 size = 0;
-
- /* SA */
- size += (u64)max_window_size * sizeof(u32);
-
- /* ISA */
- size += (u64)max_window_size * sizeof(u32);
-
- /* salink and minimum temporary space for divsufsort */
- size += max(BUILD_SA_MIN_TMP_LEN * sizeof(u32),
- (u64)max_window_size * sizeof(struct salink));
-
- return size;
-}
-
-static bool
-lz_lsa_params_valid(const struct lz_mf_params *params)
-{
- return true;
-}
-
-static bool
-lz_lsa_init(struct lz_mf *_mf)
-{
- struct lz_lsa *mf = (struct lz_lsa *)_mf;
- const u32 max_window_size = mf->base.params.max_window_size;
-
- lz_lsa_set_default_params(&mf->base.params);
-
- /* SA and ISA will share the same allocation. */
- mf->SA = MALLOC(max_window_size * 2 * sizeof(u32));
- if (!mf->SA)
- return false;
-
- mf->salink = MALLOC(max(BUILD_SA_MIN_TMP_LEN * sizeof(u32),
- max_window_size * sizeof(struct salink)));
- if (!mf->salink) {
- FREE(mf->SA);
- return false;
- }
-
- return true;
-}
-
-static void
-lz_lsa_load_window(struct lz_mf *_mf, const u8 T[], u32 n)
-{
- struct lz_lsa *mf = (struct lz_lsa *)_mf;
- u32 *ISA, *LCP;
-
- build_SA(mf->SA, T, n, (u32 *)mf->salink);
-
- /* Compute ISA (Inverse Suffix Array) in a preliminary position.
- *
- * This is just a trick to save memory. Since LCP is unneeded after
- * this function, it can be computed in any available space. The
- * storage for the ISA is the best choice because the ISA can be built
- * quickly in salink for now, then re-built in its real location at the
- * end. This is probably worth it because computing the ISA from the SA
- * is very fast, and since this match-finder is memory-hungry we'd like
- * to save as much memory as possible. */
- BUILD_BUG_ON(sizeof(mf->salink[0]) < sizeof(mf->ISA[0]));
- ISA = (u32 *)mf->salink;
- build_ISA(ISA, mf->SA, n);
-
- /* Compute LCP (Longest Common Prefix) array. */
- LCP = mf->SA + n;
- build_LCP(LCP, mf->SA, ISA, T, n);
-
- /* Initialize suffix array links. */
- init_salink(mf->salink, LCP, mf->SA, T, n,
- mf->base.params.min_match_len,
- mf->base.params.max_match_len);
- verify_salink(mf->salink, mf->SA, T, n,
- mf->base.params.min_match_len,
- mf->base.params.max_match_len);
-
- /* Compute ISA (Inverse Suffix Array) in its final position. */
- ISA = mf->SA + n;
- build_ISA(ISA, mf->SA, n);
-
- /* Save new variables and return. */
- mf->ISA = ISA;
-}
-
-static u32
-lz_lsa_get_matches(struct lz_mf *_mf, struct lz_match matches[])
-{
- struct lz_lsa *mf = (struct lz_lsa *)_mf;
- const u32 i = mf->base.cur_window_pos++;
-
- const u32 * const restrict SA = mf->SA;
- const u32 * const restrict ISA = mf->ISA;
- struct salink * const restrict link = mf->salink;
-
- /* r = Rank of the suffix at the current position. */
- const u32 r = ISA[i];
-
- /* Prepare for searching the current position. */
- lz_lsa_update_salink(r, link);
-
- /* Prefetch next position in SA and link.
- *
- * This can improve performance on large windows since the locations in
- * SA and link at which each successive search begins are in general
- * randomly distributed. */
- if (likely(i + 1 < mf->base.cur_window_size)) {
- const u32 next_r = ISA[i + 1];
- prefetch(&SA[next_r]);
- prefetch(&link[next_r]);
- }
-
- /* L = rank of next suffix to the left;
- * R = rank of next suffix to the right;
- * lenL = length of match between current position and the suffix with rank L;
- * lenR = length of match between current position and the suffix with rank R.
- *
- * This is left and right relative to the rank of the current suffix.
- * Since the suffixes in the suffix array are sorted, the longest
- * matches are immediately to the left and right (using the linked list
- * to ignore all suffixes that occur later in the window). The match
- * length decreases the farther left and right we go. We shall keep the
- * length on both sides in sync in order to choose the lowest-cost match
- * of each length.
- */
- u32 L = r - link[r].dist_to_prev;
- u32 R = r + link[r].dist_to_next;
- u32 lenL = link[r].lcpprev;
- u32 lenR = link[r].lcpnext;
-
- /* num_matches = number of matches found so far. */
- u32 num_matches = 0;
-
- /* best_offset = offset of lowest-cost match found so far.
- *
- * Shorter matches that do not have a lower offset than this are
- * discarded, since presumably it would be cheaper to output the bytes
- * from the longer match instead. */
- u32 best_offset = LZ_LSA_POS_MAX;
-
- /* count_remaining = maximum number of possible matches remaining to be
- * considered. */
- u32 count_remaining = mf->base.params.max_search_depth;
-
- /* pending_offset = offset of lowest-cost match found for the current
- * length, or 0 if none found yet. */
- u32 pending_offset = 0;
-
- /* Note: some 'goto' statements are used in the remainder of this
- * function to remove unnecessary checks and create branches that the
- * CPU may predict better. (This function is performance critical.) */
-
- if (lenL != 0 && lenL >= lenR)
- goto extend_left;
- else if (lenR != 0)
- goto extend_right;
- else
- return 0;
-
-extend_left:
- /* Search suffixes on the left until the match length has decreased
- * below the next match length on the right or to below the minimum
- * match length. */
- for (;;) {
- u32 offset;
- u32 old_L;
- u32 old_lenL;
-
- /* Check for hard cutoff on amount of work done. */
- if (count_remaining-- == 0) {
- if (pending_offset != 0) {
- /* Save pending match. */
- matches[num_matches++] = (struct lz_match) {
- .len = lenL,
- .offset = pending_offset,
- };
- }
- goto out;
- }
-
- if (SA[L] < i) {
- /* Suffix is in LZ77 dictionary. (Check was needed
- * because the salink array caps distances to save
- * memory.) */
-
- offset = i - SA[L];
-
- /* Save match offset if it results in lower cost. */
- if (offset < best_offset) {
- best_offset = offset;
- pending_offset = offset;
- }
- }
-
- /* Advance left to previous suffix. */
-
- old_L = L;
- old_lenL = lenL;
-
- L -= link[L].dist_to_prev;
-
- if (link[old_L].lcpprev < old_lenL) {
- /* Match length decreased. */
-
- lenL = link[old_L].lcpprev;
-
- if (old_lenL > lenR) {
- /* Neither the right side nor the left size has
- * any more matches of length @old_lenL. If a
- * pending match exists, save it. */
- if (pending_offset != 0) {
- matches[num_matches++] = (struct lz_match) {
- .len = old_lenL,
- .offset = pending_offset,
- };
- pending_offset = 0;
- }
-
- if (lenL >= lenR) {
- /* New match length on left is still at
- * least as large as the next match
- * length on the right: Keep extending
- * left, unless the minimum match length
- * would be underrun. */
- if (lenL == 0)
- goto out;
- goto extend_left;
- }
- }
-
- /* Here we have lenL < lenR. Extend right.
- * (No check for whether the minimum match length has
- * been underrun is needed, provided that such lengths
- * are marked as 0.) */
- goto extend_right;
- }
- }
-
-extend_right:
- /* Search suffixes on the right until the match length has decreased to
- * the next match length on the left or to below the minimum match
- * length. */
- for (;;) {
- u32 offset;
- u32 old_R;
- u32 old_lenR;
-
- /* Check for hard cutoff on amount of work done. */
- if (count_remaining-- == 0) {
- if (pending_offset != 0) {
- /* Save pending match. */
- matches[num_matches++] = (struct lz_match) {
- .len = lenR,
- .offset = pending_offset,
- };
- }
- goto out;
- }
-
- if (SA[R] < i) {
- /* Suffix is in LZ77 dictionary. (Check was needed
- * because the salink array caps distances to save
- * memory.) */
-
- offset = i - SA[R];
-
- if (offset < best_offset) {
- best_offset = offset;
- pending_offset = offset;
- }
- }
-
- /* Advance right to next suffix. */
-
- old_R = R;
- old_lenR = lenR;
-
- R += link[R].dist_to_next;
-
- if (link[old_R].lcpnext < lenR) {
- /* Match length decreased. */
-
- lenR = link[old_R].lcpnext;
-
- /* Neither the right side nor the left size has any more
- * matches of length @old_lenR. If a pending match
- * exists, save it. */
- if (pending_offset != 0) {
- matches[num_matches++] = (struct lz_match) {
- .len = old_lenR,
- .offset = pending_offset,
- };
- pending_offset = 0;
- }
-
- if (lenL >= lenR) {
- /* lenL >= lenR: Extend left, unless the
- * minimum match length would be underrun, in
- * which case we are done. */
- if (lenL == 0)
- goto out;
-
- goto extend_left;
- }
- /* lenR > lenL: Keep extending right.
- * (No check for whether the minimum match length has
- * been underrun is needed, provided that such lengths
- * are marked as 0.) */
- }
- }
-
-out:
- for (u32 i = 0; i < num_matches / 2; i++)
- swap(matches[i], matches[num_matches - 1 - i]);
- return num_matches;
-}
-
-static void
-lz_lsa_skip_positions(struct lz_mf *_mf, u32 n)
-{
- struct lz_lsa *mf = (struct lz_lsa *)_mf;
- do {
- lz_lsa_update_salink(mf->ISA[mf->base.cur_window_pos++], mf->salink);
- } while (--n);
-}
-
-static void
-lz_lsa_destroy(struct lz_mf *_mf)
-{
- struct lz_lsa *mf = (struct lz_lsa *)_mf;
-
- FREE(mf->SA);
- FREE(mf->salink);
-}
-
-const struct lz_mf_ops lz_linked_suffix_array_ops = {
- .params_valid = lz_lsa_params_valid,
- .get_needed_memory = lz_lsa_get_needed_memory,
- .init = lz_lsa_init,
- .load_window = lz_lsa_load_window,
- .get_matches = lz_lsa_get_matches,
- .skip_positions = lz_lsa_skip_positions,
- .destroy = lz_lsa_destroy,
- .struct_size = sizeof(struct lz_lsa),
-};
+++ /dev/null
-/*
- * lz_mf.c
- *
- * Interface for Lempel-Ziv match-finders.
- *
- * Copyright (c) 2014 Eric Biggers. All rights reserved.
- *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions
- * are met:
- *
- * 1. Redistributions of source code must retain the above copyright
- * notice, this list of conditions and the following disclaimer.
- *
- * 2. Redistributions in binary form must reproduce the above copyright
- * notice, this list of conditions and the following disclaimer in the
- * documentation and/or other materials provided with the distribution.
- *
- * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS "AS IS" AND
- * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
- * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
- * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE
- * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
- * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
- * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
- * BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
- * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
- * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
- * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
- */
-
-#ifdef HAVE_CONFIG_H
-# include "config.h"
-#endif
-
-#include "wimlib/lz_mf.h"
-#include "wimlib/lz_mf_ops.h"
-#include "wimlib/util.h"
-
-/* Available match-finding algorithms. */
-static const struct lz_mf_ops *mf_ops[] = {
- [LZ_MF_LCP_INTERVAL_TREE] = &lz_lcp_interval_tree_ops,
- [LZ_MF_LINKED_SUFFIX_ARRAY] = &lz_linked_suffix_array_ops,
-};
-
-static const struct lz_mf_ops *
-get_mf_ops(enum lz_mf_algo algorithm)
-{
- if ((unsigned int)algorithm >= ARRAY_LEN(mf_ops))
- return NULL;
- return mf_ops[(unsigned int)algorithm];
-}
-
-/*
- * Returns an upper bound on the number of bytes of memory that will be consumed
- * by a match-finder allocated with the specified algorithm and maximum window
- * size.
- *
- * The returned value does not include the size of the window itself. The
- * caller must account for this separately if needed.
- *
- * If @algorithm is invalid, returns 0.
- */
-u64
-lz_mf_get_needed_memory(enum lz_mf_algo algorithm, u32 max_window_size)
-{
- const struct lz_mf_ops *ops;
-
- ops = get_mf_ops(algorithm);
- if (!ops)
- return 0;
- return ops->struct_size + ops->get_needed_memory(max_window_size);
-}
-/*
- * Returns %true if and only if the specified parameters can be validly used to
- * create a match-finder using lz_mf_alloc().
- */
-bool
-lz_mf_params_valid(const struct lz_mf_params *params)
-{
- const struct lz_mf_ops *ops;
-
- /* Require that a valid algorithm be specified. */
- ops = get_mf_ops(params->algorithm);
- if (!ops)
- return false;
-
- /* Don't allow empty windows. Otherwise, some match-finding algorithms
- * might need special-case code to handle empty windows. */
- if (params->max_window_size == 0)
- return false;
-
- /* Don't allow length-1 matches, so that match-finding algorithms don't
- * need to worry about this case. Most LZ-based compression formats
- * don't allow length-1 matches, since they usually aren't helpful for
- * compression. Also, if a compressor really does need length-1
- * matches, it can easily maintain its own table of length 256
- * containing the most-recently-seen position for each byte value.
- *
- * min_match_len == 0 is valid, since that means the match-finding
- * algorithm will fill in a default value. */
- if (params->min_match_len == 1)
- return false;
-
- if (params->max_match_len != 0) {
-
- /* Don't allow length-1 matches (same reason as above). */
- if (params->max_match_len == 1)
- return false;
-
- /* Don't allow the maximum match length to be shorter than the
- * minimum match length. */
- if (params->max_match_len < params->min_match_len)
- return false;
- }
-
- /* Don't allow the needed memory size to overflow a 'size_t'. */
- if (sizeof(size_t) < sizeof(u64)) {
- u64 needed_mem = ops->get_needed_memory(params->max_window_size);
- if ((size_t)needed_mem != needed_mem)
- return false;
- }
-
- /* Call the algorithm-specific routine to finish the validation. */
- return ops->params_valid(params);
-}
-
-/*
- * Allocate a new match-finder.
- *
- * @params
- * The parameters for the match-finder. See the declaration of 'struct
- * lz_mf_params' for more information.
- *
- * Returns a pointer to the new match-finder, or NULL if out of memory or the
- * parameters are invalid. Call lz_mf_params_valid() beforehand to test the
- * parameter validity separately.
- */
-struct lz_mf *
-lz_mf_alloc(const struct lz_mf_params *params)
-{
- struct lz_mf *mf;
- const struct lz_mf_ops *ops;
-
- /* Validate the parameters. */
- if (!lz_mf_params_valid(params))
- return NULL;
-
- /* Get the match-finder operations structure. Since we just validated
- * the parameters, this is guaranteed to return a valid structure. */
- ops = get_mf_ops(params->algorithm);
- LZ_ASSERT(ops != NULL);
-
- /* Allocate memory for the match-finder structure. */
- LZ_ASSERT(ops->struct_size >= sizeof(struct lz_mf));
- mf = CALLOC(1, ops->struct_size);
- if (!mf)
- return NULL;
-
- /* Set the parameters and operations fields. */
- mf->params = *params;
- mf->ops = *ops;
-
- /* Perform algorithm-specific initialization. Normally this is where
- * most of the necessary memory is allocated. */
- if (!mf->ops.init(mf)) {
- FREE(mf);
- return NULL;
- }
-
- /* The algorithm must have set min_match_len and max_match_len if either
- * was 0. */
- LZ_ASSERT(mf->params.min_match_len >= 2);
- LZ_ASSERT(mf->params.max_match_len >= mf->params.min_match_len);
-
- return mf;
-}
-
-/*
- * Load a window into the match-finder.
- *
- * @mf
- * The match-finder into which to load the window.
- * @window
- * Pointer to the window to load. This memory must remain available,
- * unmodified, while the match-finder is being used.
- * @size
- * The size of the window, in bytes. This can't be larger than the
- * @max_window_size parameter. In addition, this can't be 0.
- *
- * Note: this interface does not support sliding windows!
- */
-void
-lz_mf_load_window(struct lz_mf *mf, const u8 *window, u32 size)
-{
- /* Can't be an empty window, and can't be larger than the maximum window
- * size with which the match-finder was allocated. */
- LZ_ASSERT(size > 0);
- LZ_ASSERT(size <= mf->params.max_window_size);
-
- /* Save the window and initialize the current position. */
- mf->cur_window = window;
- mf->cur_window_size = size;
- mf->cur_window_pos = 0;
-
- /* Call into the algorithm-specific window load code. */
- mf->ops.load_window(mf, window, size);
-}
-
-/*
- * Retrieve a list of matches at the next position in the window.
- *
- * @mf
- * The match-finder into which a window has been loaded using
- * lz_mf_load_window().
- * @matches
- * The array into which the matches will be returned. The returned match
- * count will not exceed the minimum of @max_search_depth and (@len_limit -
- * @min_match_len + 1), where @len_limit is itself defined as
- * min(@max_match_len, @nice_match_len).
- *
- * The return value is the number of matches that were found and stored in the
- * 'matches' array. The matches will be ordered by strictly increasing length
- * and strictly increasing offset. No match shall have length less than
- * @min_match_len, and no match shall have length greater than @max_match_len.
- * The return value may be 0, which indicates that no matches were found.
- *
- * On completion, the match-finder is advanced to the next position in the
- * window.
- *
- * Note: in-non-debug mode, the inline definition of this gets used instead.
- * They are the same, except that the non-inline version below validates the
- * results to help debug match-finding algorithms.
- */
-#ifdef ENABLE_LZ_DEBUG
-u32
-lz_mf_get_matches(struct lz_mf *mf, struct lz_match *matches)
-{
- LZ_ASSERT(mf->cur_window_pos < mf->cur_window_size);
-
- const u32 orig_pos = mf->cur_window_pos;
- const u32 len_limit = min(mf->params.max_match_len,
- lz_mf_get_bytes_remaining(mf));
- const u8 * const strptr = lz_mf_get_window_ptr(mf);
-
- const u32 num_matches = mf->ops.get_matches(mf, matches);
-
- LZ_ASSERT(mf->cur_window_pos == orig_pos + 1);
-
-#if 0
- fprintf(stderr, "Pos %"PRIu32"/%"PRIu32": %"PRIu32" matches\n",
- orig_pos, mf->cur_window_size, num_matches);
- for (u32 i = 0; i < num_matches; i++) {
- fprintf(stderr, "\tLen %"PRIu32" Offset %"PRIu32"\n",
- matches[i].len, matches[i].offset);
- }
-#endif
-
- /* Validate the matches. */
- for (u32 i = 0; i < num_matches; i++) {
- const u32 len = matches[i].len;
- const u32 offset = matches[i].offset;
- const u8 *matchptr;
-
- /* Length valid? */
- LZ_ASSERT(len >= mf->params.min_match_len);
- LZ_ASSERT(len <= len_limit);
-
- /* Offset valid? */
- LZ_ASSERT(offset >= 1);
- LZ_ASSERT(offset <= orig_pos);
-
- /* Lengths and offsets strictly increasing? */
- if (i > 0) {
- LZ_ASSERT(len > matches[i - 1].len);
- LZ_ASSERT(offset > matches[i - 1].offset);
- }
-
- /* Actually a match? */
- matchptr = strptr - offset;
- LZ_ASSERT(!memcmp(strptr, matchptr, len));
-
- /* Match can't be extended further? */
- LZ_ASSERT(len == len_limit || strptr[len] != matchptr[len]);
- }
-
- return num_matches;
-}
-#endif /* ENABLE_LZ_DEBUG */
-
-/*
- * Skip 'n' positions in the match-finder. This is a faster alternative to
- * calling lz_mf_get_matches() at each position to advance the match-finder.
- *
- * 'n' must be greater than 0.
- *
- * Note: in-non-debug mode, the inline definition of this gets used instead.
- * They are the same, except the non-inline version below does extra checks.
- */
-#ifdef ENABLE_LZ_DEBUG
-void
-lz_mf_skip_positions(struct lz_mf *mf, const u32 n)
-{
- LZ_ASSERT(n > 0);
- LZ_ASSERT(n <= lz_mf_get_bytes_remaining(mf));
-
- const u32 orig_pos = mf->cur_window_pos;
-
- mf->ops.skip_positions(mf, n);
-
- LZ_ASSERT(mf->cur_window_pos == orig_pos + n);
-}
-#endif
-
-/*
- * Free the match-finder.
- *
- * This frees all memory that was allocated by the call to lz_mf_alloc().
- */
-void
-lz_mf_free(struct lz_mf *mf)
-{
- if (mf) {
- mf->ops.destroy(mf);
- #ifdef ENABLE_LZ_DEBUG
- memset(mf, 0, mf->ops.struct_size);
- #endif
- FREE(mf);
- }
-}
+++ /dev/null
-/*
- * lz_suffix_array_utils.c
- *
- * Common utilities for suffix-array based Lempel-Ziv match-finding algorithms.
- *
- * Copyright (c) 2014 Eric Biggers. All rights reserved.
- *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions
- * are met:
- *
- * 1. Redistributions of source code must retain the above copyright
- * notice, this list of conditions and the following disclaimer.
- *
- * 2. Redistributions in binary form must reproduce the above copyright
- * notice, this list of conditions and the following disclaimer in the
- * documentation and/or other materials provided with the distribution.
- *
- * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS "AS IS" AND
- * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
- * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
- * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE
- * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
- * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
- * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
- * BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
- * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
- * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
- * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
- */
-
-#ifdef HAVE_CONFIG_H
-# include "config.h"
-#endif
-
-#include "wimlib/divsufsort.h"
-#include "wimlib/lz_mf.h"
-#include "wimlib/lz_suffix_array_utils.h"
-#include "wimlib/util.h"
-
-/* If ENABLE_LZ_DEBUG is defined, verify that the suffix array satisfies its
- * definition.
- *
- * WARNING: this is for debug use only as it does not necessarily run in linear
- * time!!! */
-static void
-verify_SA(const u32 *SA, const u8 *T, u32 n, u32 *tmp)
-{
-#ifdef ENABLE_LZ_DEBUG
- /* Ensure the SA contains exactly one of each i in [0, n - 1]. */
- for (u32 i = 0; i < n; i++)
- tmp[i] = 0;
- for (u32 r = 0; r < n; r++) {
- u32 i = SA[r];
- LZ_ASSERT(i < n);
- LZ_ASSERT(!tmp[i]);
- tmp[i] = 1;
- }
-
- /* Ensure the suffix with rank r is lexicographically less than the
- * suffix with rank (r + 1) for all r in [0, n - 2]. */
- for (u32 r = 0; r < n - 1; r++) {
-
- u32 i1 = SA[r];
- u32 i2 = SA[r + 1];
-
- u32 n1 = n - i1;
- u32 n2 = n - i2;
-
- int res = memcmp(&T[i1], &T[i2], min(n1, n2));
- LZ_ASSERT(res < 0 || (res == 0 && n1 < n2));
- }
-#endif /* ENABLE_LZ_DEBUG */
-}
-
-/*
- * Build the suffix array (SA) for the specified "text".
- *
- * The SA is a sorted array of the text's suffixes, represented by indices into
- * the text. It can equivalently be viewed as a mapping from suffix rank to
- * suffix position.
- *
- * To build the SA, we currently rely on libdivsufsort, which uses an
- * induced-sorting-based algorithm. In practice, this seems to be the fastest
- * suffix array construction algorithm currently available.
- *
- * References:
- *
- * Y. Mori. libdivsufsort, a lightweight suffix-sorting library.
- * https://code.google.com/p/libdivsufsort/.
- *
- * G. Nong, S. Zhang, and W.H. Chan. 2009. Linear Suffix Array
- * Construction by Almost Pure Induced-Sorting. Data Compression
- * Conference, 2009. DCC '09. pp. 193 - 202.
- *
- * S.J. Puglisi, W.F. Smyth, and A. Turpin. 2007. A Taxonomy of Suffix
- * Array Construction Algorithms. ACM Computing Surveys (CSUR) Volume 39
- * Issue 2, 2007 Article No. 4.
- */
-void
-build_SA(u32 *SA, const u8 *T, u32 n, u32 *tmp)
-{
- BUILD_BUG_ON(BUILD_SA_MIN_TMP_LEN !=
- DIVSUFSORT_TMP1_LEN + DIVSUFSORT_TMP2_LEN);
-
- /* Note: divsufsort() needs temporary space --- one array with 256
- * spaces and one array with 65536 spaces. The implementation of
- * divsufsort() has been modified from the original to use the provided
- * temporary space instead of allocating its own, since we don't want to
- * have to deal with malloc() failures here. */
- divsufsort(T, SA, n, tmp, tmp + DIVSUFSORT_TMP1_LEN);
-
- verify_SA(SA, T, n, tmp);
-}
-
-
-/* Build the inverse suffix array @ISA from the suffix array @SA in linear time.
- *
- * Whereas the suffix array is a mapping from suffix rank to suffix position,
- * the inverse suffix array is a mapping from suffix position to suffix rank.
- */
-void
-build_ISA(u32 * restrict ISA, const u32 * restrict SA, u32 n)
-{
- for (u32 r = 0; r < n; r++)
- ISA[SA[r]] = r;
-}
-
-/* If ENABLE_LZ_DEBUG is defined, verify that the LCP (Longest Common Prefix)
- * array satisfies its definition.
- *
- * WARNING: this is for debug use only as it does not necessarily run in linear
- * time!!! */
-static void
-verify_LCP(const u32 *LCP, const u32 *SA, const u8 *T, u32 n)
-{
-#ifdef ENABLE_LZ_DEBUG
- for (u32 r = 0; r < n - 1; r++) {
- u32 i1 = SA[r];
- u32 i2 = SA[r + 1];
- u32 lcp = LCP[r + 1];
-
- u32 n1 = n - i1;
- u32 n2 = n - i2;
-
- LZ_ASSERT(lcp <= min(n1, n2));
-
- LZ_ASSERT(memcmp(&T[i1], &T[i2], lcp) == 0);
- if (lcp < min(n1, n2))
- LZ_ASSERT(T[i1 + lcp] != T[i2 + lcp]);
- }
-#endif /* ENABLE_LZ_DEBUG */
-}
-
-/*
- * Build the LCP (Longest Common Prefix) array in linear time.
- *
- * LCP[r] will be the length of the longest common prefix between the suffixes
- * with positions SA[r - 1] and SA[r]. LCP[0] will be undefined.
- *
- * Algorithm taken from Kasai et al. (2001), but modified slightly to take into
- * account that with bytes in the real world, there is no unique symbol at the
- * end of the string.
- *
- * References:
- *
- * Kasai et al. 2001. Linear-Time Longest-Common-Prefix Computation in
- * Suffix Arrays and Its Applications. CPM '01 Proceedings of the 12th
- * Annual Symposium on Combinatorial Pattern Matching pp. 181-192.
- */
-void
-build_LCP(u32 * restrict LCP, const u32 * restrict SA,
- const u32 * restrict ISA, const u8 * restrict T, u32 n)
-{
- u32 h, i, r, j, lim;
-
- h = 0;
- for (i = 0; i < n; i++) {
- r = ISA[i];
- if (r > 0) {
- j = SA[r - 1];
- lim = min(n - i, n - j);
-
- while (h < lim && T[i + h] == T[j + h])
- h++;
- LCP[r] = h;
- if (h > 0)
- h--;
- }
- }
-
- verify_LCP(LCP, SA, T, n);
-}
#include "wimlib/compressor_ops.h"
#include "wimlib/endianness.h"
#include "wimlib/error.h"
-#include "wimlib/lz_mf.h"
+#include "wimlib/lcpit_matchfinder.h"
#include "wimlib/lz_repsearch.h"
#include "wimlib/lzms_common.h"
#include "wimlib/unaligned.h"
struct lzms_compressor_params {
u32 min_match_length;
u32 nice_match_length;
- u32 max_search_depth;
u32 optim_array_length;
};
u32 cur_window_size;
/* Lempel-Ziv match-finder */
- struct lz_mf *mf;
+ struct lcpit_matchfinder mf;
/* Temporary space to store found matches */
struct lz_match *matches;
/*
* Consider coding each match in @matches as an explicit offset match.
*
- * @matches must be sorted by strictly increasing length and strictly increasing
- * offset. This is guaranteed by the match-finder.
+ * @matches must be sorted by strictly decreasing length. This is guaranteed by
+ * the match-finder.
*
* We consider each length from the minimum (2) to the longest
* (matches[num_matches - 1].len). For each length, we consider only the
base_cost += lzms_rc_bit_cost(&c->lz_match_range_encoder,
cur_optimum_ptr->state.lz_match_state, 0);
len = 2;
- i = 0;
+ i = num_matches - 1;
do {
position_cost = base_cost + lzms_lz_offset_cost(c, matches[i].offset);
do {
<< MC_OFFSET_SHIFT) | len;
(cur_optimum_ptr + len)->cost = cost;
}
- } while (++len <= matches[i].len);
- } while (++i != num_matches);
+ } while (++len <= matches[i].length);
+ } while (i--);
}
static void
for (;;) {
/* Find explicit offset matches with the current position. */
- num_matches = lz_mf_get_matches(c->mf, c->matches);
-
+ num_matches = lcpit_matchfinder_get_matches(&c->mf, c->matches);
if (num_matches) {
/*
* Find the longest repeat offset match with the current
* choose it immediately. */
if (rep_max_len >= c->params.nice_match_length) {
- lz_mf_skip_positions(c->mf, rep_max_len - 1);
+ lcpit_matchfinder_skip_bytes(&c->mf, rep_max_len - 1);
window_ptr += rep_max_len;
if (cur_optimum_ptr != c->optimum)
rep_max_len, rep_max_idx);
}
- longest_len = c->matches[num_matches - 1].len;
+ longest_len = c->matches[0].length;
/* If there's a very long explicit offset match, choose
* it immediately. */
if (longest_len >= c->params.nice_match_length) {
- lz_mf_skip_positions(c->mf, longest_len - 1);
+ u32 offset = c->matches[0].offset;
+
+ /* Extend the match as far as possible. (The
+ * LCP-interval tree matchfinder only reports up
+ * to the "nice" length.) */
+ longest_len = lz_extend(window_ptr,
+ window_ptr - offset,
+ longest_len,
+ window_end - window_ptr);
+
+ lcpit_matchfinder_skip_bytes(&c->mf, longest_len - 1);
window_ptr += longest_len;
if (cur_optimum_ptr != c->optimum)
lzms_encode_item_list(c, cur_optimum_ptr);
- lzms_encode_lz_explicit_offset_match(c, longest_len,
- c->matches[num_matches - 1].offset);
+ lzms_encode_lz_explicit_offset_match(c, longest_len, offset);
c->optimum[0].state = cur_optimum_ptr->state;
lzms_update_match_state(&c->optimum[0].state, 0);
lzms_update_lz_match_state(&c->optimum[0].state, 0);
- c->optimum[0].state.lru.upcoming_offset =
- c->matches[num_matches - 1].offset;
+ c->optimum[0].state.lru.upcoming_offset = offset;
lzms_update_lz_lru_queue(&c->optimum[0].state.lru);
goto begin;
else
params->min_match_length = 3;
- /* Scale nice_match_length and max_search_depth with the compression
- * level. But to allow an optimization on length cost calculations,
- * don't allow nice_match_length to exceed LZMS_NUM_FAST_LENGTH. */
+ /* Scale nice_match_length with the compression level. But to allow an
+ * optimization on length cost calculations, don't allow
+ * nice_match_length to exceed LZMS_NUM_FAST_LENGTH. */
params->nice_match_length = ((u64)compression_level * 32) / 50;
if (params->nice_match_length < params->min_match_length)
params->nice_match_length = params->min_match_length;
if (params->nice_match_length > LZMS_NUM_FAST_LENGTHS)
params->nice_match_length = LZMS_NUM_FAST_LENGTHS;
- params->max_search_depth = compression_level;
-
params->optim_array_length = 1024;
}
-/* Given the internal compression parameters and maximum window size, build the
- * Lempel-Ziv match-finder parameters. */
-static void
-lzms_build_mf_params(const struct lzms_compressor_params *lzms_params,
- u32 max_window_size, struct lz_mf_params *mf_params)
-{
- memset(mf_params, 0, sizeof(*mf_params));
-
- /* Choose an appropriate match-finding algorithm. */
- if (max_window_size <= 33554432)
- mf_params->algorithm = LZ_MF_LCP_INTERVAL_TREE;
- else
- mf_params->algorithm = LZ_MF_LINKED_SUFFIX_ARRAY;
-
- mf_params->max_window_size = max_window_size;
- mf_params->min_match_len = lzms_params->min_match_length;
- mf_params->max_search_depth = lzms_params->max_search_depth;
- mf_params->nice_match_len = lzms_params->nice_match_length;
-}
-
static void
lzms_free_compressor(void *_c);
lzms_get_needed_memory(size_t max_block_size, unsigned int compression_level)
{
struct lzms_compressor_params params;
- struct lz_mf_params mf_params;
u64 size = 0;
if (max_block_size > LZMS_MAX_BUFFER_SIZE)
return 0;
lzms_build_params(compression_level, ¶ms);
- lzms_build_mf_params(¶ms, max_block_size, &mf_params);
size += sizeof(struct lzms_compressor);
size += max_block_size;
/* mf */
- size += lz_mf_get_needed_memory(mf_params.algorithm, max_block_size);
+ size += lcpit_matchfinder_get_needed_memory(max_block_size);
/* matches */
- size += min(params.max_search_depth, params.nice_match_length) *
+ size += (params.nice_match_length - params.min_match_length + 1) *
sizeof(struct lz_match);
/* optimum */
{
struct lzms_compressor *c;
struct lzms_compressor_params params;
- struct lz_mf_params mf_params;
if (max_block_size > LZMS_MAX_BUFFER_SIZE)
return WIMLIB_ERR_INVALID_PARAM;
lzms_build_params(compression_level, ¶ms);
- lzms_build_mf_params(¶ms, max_block_size, &mf_params);
- if (!lz_mf_params_valid(&mf_params))
- return WIMLIB_ERR_INVALID_PARAM;
c = CALLOC(1, sizeof(struct lzms_compressor));
if (!c)
if (!c->cur_window)
goto oom;
- c->mf = lz_mf_alloc(&mf_params);
- if (!c->mf)
+ if (!lcpit_matchfinder_init(&c->mf, max_block_size,
+ c->params.min_match_length,
+ c->params.nice_match_length))
goto oom;
- c->matches = MALLOC(min(params.max_search_depth,
- params.nice_match_length) *
+ c->matches = MALLOC((params.nice_match_length - params.min_match_length + 1) *
sizeof(struct lz_match));
if (!c->matches)
goto oom;
c->last_target_usages, false);
/* Load the window into the match-finder. */
- lz_mf_load_window(c->mf, c->cur_window, c->cur_window_size);
+ lcpit_matchfinder_load_buffer(&c->mf, c->cur_window, c->cur_window_size);
/* Compute and encode a literal/match sequence that decompresses to the
* preprocessed data. */
if (c) {
FREE(c->cur_window);
- lz_mf_free(c->mf);
+ lcpit_matchfinder_destroy(&c->mf);
FREE(c->matches);
FREE(c->optimum);
FREE(c);
git://wimlib.net / wimlib / commitdiff