aboutsummaryrefslogtreecommitdiff
path: root/tools/rasm/lzsa-master/src/matchfinder.c
diff options
context:
space:
mode:
authorJuan J. Martinez <jjm@usebox.net>2022-09-06 07:37:20 +0100
committerJuan J. Martinez <jjm@usebox.net>2022-09-06 07:37:20 +0100
commit30bf0f51335e87812ffeb54e9437f0b6a1514d67 (patch)
tree9c85a2de53b4da69fcfaa84488cc6c12ebd3e5d0 /tools/rasm/lzsa-master/src/matchfinder.c
parentd8990284057e6401d0374f439df51879595d804d (diff)
downloadubox-msx-lib-30bf0f51335e87812ffeb54e9437f0b6a1514d67.tar.gz
ubox-msx-lib-30bf0f51335e87812ffeb54e9437f0b6a1514d67.zip
Updated rasm to 1.7
Diffstat (limited to 'tools/rasm/lzsa-master/src/matchfinder.c')
-rw-r--r--tools/rasm/lzsa-master/src/matchfinder.c361
1 files changed, 361 insertions, 0 deletions
diff --git a/tools/rasm/lzsa-master/src/matchfinder.c b/tools/rasm/lzsa-master/src/matchfinder.c
new file mode 100644
index 0000000..3de2cfa
--- /dev/null
+++ b/tools/rasm/lzsa-master/src/matchfinder.c
@@ -0,0 +1,361 @@
+/*
+ * matchfinder.c - LZ match finder implementation
+ *
+ * The following copying information applies to this specific source code file:
+ *
+ * Written in 2019 by Emmanuel Marty <marty.emmanuel@gmail.com>
+ * Portions written in 2014-2015 by Eric Biggers <ebiggers3@gmail.com>
+ *
+ * To the extent possible under law, the author(s) have dedicated all copyright
+ * and related and neighboring rights to this software to the public domain
+ * worldwide via the Creative Commons Zero 1.0 Universal Public Domain
+ * Dedication (the "CC0").
+ *
+ * This software is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
+ * FOR A PARTICULAR PURPOSE. See the CC0 for more details.
+ *
+ * You should have received a copy of the CC0 along with this software; if not
+ * see <http://creativecommons.org/publicdomain/zero/1.0/>.
+ */
+
+/*
+ * Uses the libdivsufsort library Copyright (c) 2003-2008 Yuta Mori
+ *
+ * Inspired by LZ4 by Yann Collet. https://github.com/lz4/lz4
+ * With help, ideas, optimizations and speed measurements by spke <zxintrospec@gmail.com>
+ * With ideas from Lizard by Przemyslaw Skibinski and Yann Collet. https://github.com/inikep/lizard
+ * Also with ideas from smallz4 by Stephan Brumme. https://create.stephan-brumme.com/smallz4/
+ *
+ */
+
+#include <stdlib.h>
+#include <string.h>
+#include "matchfinder.h"
+#include "format.h"
+#include "lib.h"
+
+/**
+ * Hash index into TAG_BITS
+ *
+ * @param nIndex index value
+ *
+ * @return hash
+ */
+static inline int lzsa_get_index_tag(unsigned int nIndex) {
+ return (int)(((unsigned long long)nIndex * 11400714819323198485ULL) >> (64ULL - TAG_BITS));
+}
+
+/**
+ * Parse input data, build suffix array and overlaid data structures to speed up match finding
+ *
+ * @param pCompressor compression context
+ * @param pInWindow pointer to input data window (previously compressed bytes + bytes to compress)
+ * @param nInWindowSize total input size in bytes (previously compressed bytes + bytes to compress)
+ *
+ * @return 0 for success, non-zero for failure
+ */
+int lzsa_build_suffix_array(lzsa_compressor *pCompressor, const unsigned char *pInWindow, const int nInWindowSize) {
+ unsigned int *intervals = pCompressor->intervals;
+
+ /* Build suffix array from input data */
+ if (divsufsort_build_array(&pCompressor->divsufsort_context, pInWindow, (saidx_t*)intervals, nInWindowSize) != 0) {
+ return 100;
+ }
+
+ int *PLCP = (int*)pCompressor->pos_data; /* Use temporarily */
+ int *Phi = PLCP;
+ int nCurLen = 0;
+ int i, r;
+
+ /* Compute the permuted LCP first (Kärkkäinen method) */
+ Phi[intervals[0]] = -1;
+ for (i = 1; i < nInWindowSize; i++)
+ Phi[intervals[i]] = intervals[i - 1];
+ for (i = 0; i < nInWindowSize; i++) {
+ if (Phi[i] == -1) {
+ PLCP[i] = 0;
+ continue;
+ }
+ int nMaxLen = (i > Phi[i]) ? (nInWindowSize - i) : (nInWindowSize - Phi[i]);
+ while (nCurLen < nMaxLen && pInWindow[i + nCurLen] == pInWindow[Phi[i] + nCurLen]) nCurLen++;
+ PLCP[i] = nCurLen;
+ if (nCurLen > 0)
+ nCurLen--;
+ }
+
+ /* Rotate permuted LCP into the LCP. This has better cache locality than the direct Kasai LCP method. This also
+ * saves us from having to build the inverse suffix array index, as the LCP is calculated without it using this method,
+ * and the interval builder below doesn't need it either. */
+ intervals[0] &= POS_MASK;
+ int nMinMatchSize = pCompressor->min_match_size;
+
+ if (pCompressor->format_version >= 2) {
+ for (i = 1; i < nInWindowSize; i++) {
+ int nIndex = (int)(intervals[i] & POS_MASK);
+ int nLen = PLCP[nIndex];
+ if (nLen < nMinMatchSize)
+ nLen = 0;
+ if (nLen > LCP_MAX)
+ nLen = LCP_MAX;
+ int nTaggedLen = 0;
+ if (nLen)
+ nTaggedLen = (nLen << TAG_BITS) | (lzsa_get_index_tag((unsigned int)nIndex) & ((1 << TAG_BITS) - 1));
+ intervals[i] = ((unsigned int)nIndex) | (((unsigned int)nTaggedLen) << LCP_SHIFT);
+ }
+ }
+ else {
+ for (i = 1; i < nInWindowSize; i++) {
+ int nIndex = (int)(intervals[i] & POS_MASK);
+ int nLen = PLCP[nIndex];
+ if (nLen < nMinMatchSize)
+ nLen = 0;
+ if (nLen > LCP_AND_TAG_MAX)
+ nLen = LCP_AND_TAG_MAX;
+ intervals[i] = ((unsigned int)nIndex) | (((unsigned int)nLen) << LCP_SHIFT);
+ }
+ }
+
+ /**
+ * Build intervals for finding matches
+ *
+ * Methodology and code fragment taken from wimlib (CC0 license):
+ * https://wimlib.net/git/?p=wimlib;a=blob_plain;f=src/lcpit_matchfinder.c;h=a2d6a1e0cd95200d1f3a5464d8359d5736b14cbe;hb=HEAD
+ */
+ unsigned int * const SA_and_LCP = intervals;
+ unsigned int *pos_data = pCompressor->pos_data;
+ unsigned int next_interval_idx;
+ unsigned int *top = pCompressor->open_intervals;
+ unsigned int prev_pos = SA_and_LCP[0] & POS_MASK;
+
+ *top = 0;
+ intervals[0] = 0;
+ next_interval_idx = 1;
+
+ for (r = 1; r < nInWindowSize; r++) {
+ const unsigned int next_pos = SA_and_LCP[r] & POS_MASK;
+ const unsigned int next_lcp = SA_and_LCP[r] & LCP_MASK;
+ const unsigned int top_lcp = *top & LCP_MASK;
+
+ 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 */
+ *++top = next_lcp | next_interval_idx++;
+ pos_data[prev_pos] = *top;
+ }
+ else {
+ /* Closing the deepest open interval */
+ pos_data[prev_pos] = *top;
+ for (;;) {
+ const unsigned int closed_interval_idx = *top-- & POS_MASK;
+ const unsigned int superinterval_lcp = *top & LCP_MASK;
+
+ if (next_lcp == superinterval_lcp) {
+ /* Continuing the superinterval */
+ intervals[closed_interval_idx] = *top;
+ 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 */
+ *++top = next_lcp | next_interval_idx++;
+ intervals[closed_interval_idx] = *top;
+ break;
+ }
+ else {
+ /* Also closing the superinterval */
+ intervals[closed_interval_idx] = *top;
+ }
+ }
+ }
+ prev_pos = next_pos;
+ }
+
+ /* Close any still-open intervals. */
+ pos_data[prev_pos] = *top;
+ for (; top > pCompressor->open_intervals; top--)
+ intervals[*top & POS_MASK] = *(top - 1);
+
+ /* Success */
+ return 0;
+}
+
+/**
+ * Find matches at the specified offset in the input window
+ *
+ * @param pCompressor compression context
+ * @param nOffset offset to find matches at, in the input window
+ * @param pMatches pointer to returned matches
+ * @param nMaxMatches maximum number of matches to return (0 for none)
+ * @param nInWindowSize total input size in bytes (previously compressed bytes + bytes to compress)
+ *
+ * @return number of matches
+ */
+int lzsa_find_matches_at(lzsa_compressor *pCompressor, const int nOffset, lzsa_match *pMatches, const int nMaxMatches, const int nInWindowSize) {
+ unsigned int *intervals = pCompressor->intervals;
+ unsigned int *pos_data = pCompressor->pos_data;
+ unsigned int ref;
+ unsigned int super_ref;
+ unsigned int match_pos;
+ lzsa_match *matchptr;
+ int nPrevOffset = 0;
+
+ /**
+ * Find matches using intervals
+ *
+ * Taken from wimlib (CC0 license):
+ * https://wimlib.net/git/?p=wimlib;a=blob_plain;f=src/lcpit_matchfinder.c;h=a2d6a1e0cd95200d1f3a5464d8359d5736b14cbe;hb=HEAD
+ */
+
+ /* Get the deepest lcp-interval containing the current suffix. */
+ ref = pos_data[nOffset];
+
+ pos_data[nOffset] = 0;
+
+ /* Ascend until we reach a visited interval, the root, or a child of the
+ * root. Link unvisited intervals to the current suffix as we go. */
+ while ((super_ref = intervals[ref & POS_MASK]) & LCP_MASK) {
+ intervals[ref & POS_MASK] = nOffset | VISITED_FLAG;
+ ref = super_ref;
+ }
+
+ if (super_ref == 0) {
+ /* In this case, the current interval may be any of:
+ * (1) the root;
+ * (2) an unvisited child of the root */
+
+ if (ref != 0) /* Not the root? */
+ intervals[ref & POS_MASK] = nOffset | VISITED_FLAG;
+ return 0;
+ }
+
+ /* Ascend indirectly via pos_data[] links. */
+ match_pos = super_ref & EXCL_VISITED_MASK;
+ matchptr = pMatches;
+
+ if (pCompressor->format_version >= 2 && nInWindowSize < 65536) {
+ if ((matchptr - pMatches) < nMaxMatches) {
+ int nMatchOffset = (int)(nOffset - match_pos);
+
+ if (nMatchOffset <= MAX_OFFSET) {
+ matchptr->length = (unsigned short)(ref >> (LCP_SHIFT + TAG_BITS));
+ matchptr->offset = (unsigned short)nMatchOffset;
+ matchptr++;
+
+ nPrevOffset = nMatchOffset;
+ }
+ }
+ }
+
+ for (;;) {
+ if ((super_ref = pos_data[match_pos]) > ref) {
+ match_pos = intervals[super_ref & POS_MASK] & EXCL_VISITED_MASK;
+
+ if (pCompressor->format_version >= 2 && nInWindowSize < 65536) {
+ if ((matchptr - pMatches) < nMaxMatches) {
+ int nMatchOffset = (int)(nOffset - match_pos);
+
+ if (nMatchOffset <= MAX_OFFSET && nMatchOffset != nPrevOffset) {
+ matchptr->length = ((unsigned short)(ref >> (LCP_SHIFT + TAG_BITS))) | 0x8000;
+ matchptr->offset = (unsigned short)nMatchOffset;
+ matchptr++;
+
+ nPrevOffset = nMatchOffset;
+ }
+ }
+ }
+ }
+
+ while ((super_ref = pos_data[match_pos]) > ref)
+ match_pos = intervals[super_ref & POS_MASK] & EXCL_VISITED_MASK;
+ intervals[ref & POS_MASK] = nOffset | VISITED_FLAG;
+ pos_data[match_pos] = ref;
+
+ if ((matchptr - pMatches) < nMaxMatches) {
+ int nMatchOffset = (int)(nOffset - match_pos);
+
+ if (nMatchOffset <= MAX_OFFSET && nMatchOffset != nPrevOffset) {
+ if (pCompressor->format_version >= 2) {
+ matchptr->length = (unsigned short)(ref >> (LCP_SHIFT + TAG_BITS));
+ }
+ else {
+ matchptr->length = (unsigned short)(ref >> LCP_SHIFT);
+ }
+ matchptr->offset = (unsigned short)nMatchOffset;
+ matchptr++;
+ }
+ }
+
+ if (super_ref == 0)
+ break;
+ ref = super_ref;
+ match_pos = intervals[ref & POS_MASK] & EXCL_VISITED_MASK;
+
+ if (pCompressor->format_version >= 2 && nInWindowSize < 65536) {
+ if ((matchptr - pMatches) < nMaxMatches) {
+ int nMatchOffset = (int)(nOffset - match_pos);
+
+ if (nMatchOffset <= MAX_OFFSET && nMatchOffset != nPrevOffset) {
+ matchptr->length = ((unsigned short)(ref >> (LCP_SHIFT + TAG_BITS))) | 0x8000;
+ matchptr->offset = (unsigned short)nMatchOffset;
+
+ if ((matchptr->length & 0x7fff) > 2) {
+ matchptr++;
+
+ nPrevOffset = nMatchOffset;
+ }
+ }
+ }
+ }
+ }
+
+ return (int)(matchptr - pMatches);
+}
+
+/**
+ * Skip previously compressed bytes
+ *
+ * @param pCompressor compression context
+ * @param nStartOffset current offset in input window (typically 0)
+ * @param nEndOffset offset to skip to in input window (typically the number of previously compressed bytes)
+ */
+void lzsa_skip_matches(lzsa_compressor *pCompressor, const int nStartOffset, const int nEndOffset) {
+ lzsa_match match;
+ int i;
+
+ /* Skipping still requires scanning for matches, as this also performs a lazy update of the intervals. However,
+ * we don't store the matches. */
+ for (i = nStartOffset; i < nEndOffset; i++) {
+ lzsa_find_matches_at(pCompressor, i, &match, 0, 0);
+ }
+}
+
+/**
+ * Find all matches for the data to be compressed
+ *
+ * @param pCompressor compression context
+ * @param nMatchesPerOffset maximum number of matches to store for each offset
+ * @param nStartOffset current offset in input window (typically the number of previously compressed bytes)
+ * @param nEndOffset offset to end finding matches at (typically the size of the total input window in bytes
+ */
+void lzsa_find_all_matches(lzsa_compressor *pCompressor, const int nMatchesPerOffset, const int nStartOffset, const int nEndOffset) {
+ lzsa_match *pMatch = pCompressor->match;
+ int i;
+
+ for (i = nStartOffset; i < nEndOffset; i++) {
+ int nMatches = lzsa_find_matches_at(pCompressor, i, pMatch, nMatchesPerOffset, nEndOffset - nStartOffset);
+
+ while (nMatches < nMatchesPerOffset) {
+ pMatch[nMatches].length = 0;
+ pMatch[nMatches].offset = 0;
+ nMatches++;
+ }
+
+ pMatch += nMatchesPerOffset;
+ }
+}