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eu.interedition.collatex.suffixarray.DeepShallow Maven / Gradle / Ivy

package eu.interedition.collatex.suffixarray;

import java.util.Arrays;

/**
 * 

* Straightforward reimplementation of deep-shallow algorithm given in: * Giovanni Manzini and Paolo Ferragina. Engineering a lightweight suffix array construction algorithm. * *

* This implementation is basically a translation of the C version given by Giovanni Manzini *

* The implementation of this algorithm makes some assumptions about the input. See * {@link #buildSuffixArray(int[], int, int)} for details. * * @author Michał Nowak (Carrot Search) * @author Dawid Weiss (Carrot Search) */ public class DeepShallow implements ISuffixArrayBuilder { private static class SplitGroupResult { final int equal; final int lower; public SplitGroupResult(int equal, int lower) { this.equal = equal; this.lower = lower; } } private static class Node { int skip; int key; Node right; // original author uses down as a pointer to another Node, but sometimes he stores // int values in it. Because of that, we have two following variables (luckily we // could do so :)). Node down; int downInt; } /** * TODO: What is this magic constant? Do not make it public and do not reuse it anywhere where it isn't needed * (especially not in the tests). If this algorithm has special considerations, we can run algorithm-specific tests * with an appropriate decorator. */ final static int OVERSHOOT = 575; private final static int SETMASK = 1 << 30; private final static int CLEARMASK = ~SETMASK; private final static int MARKER = 1 << 31; /** * recursion limit for mk quicksort: */ private final static int MK_QS_TRESH = 20; private final static int MAX_TRESH = 30; /** * limit for shallow_sort */ private final static int SHALLOW_LIMIT = 550; /** * maximum offset considered when searching a pseudo anchor */ private final static int MAX_PSEUDO_ANCHOR_OFFSET = 0; /** * maximum ratio bucket_size/group_size accepted for pseudo anchor_sorting */ private final static int B2G_RATIO = 1000; /** * Update anchor ranks when determining rank for pseudo-sorting */ private final static boolean UPDATE_ANCHOR_RANKS = false; /** * blind sort is used for groups of size ≤ Text_size/Blind_sort_ratio */ private final static int BLIND_SORT_RATIO = 2000; private final static int STACK_SIZE = 100; private int[] text; private int textSize; private int[] suffixArray; private int anchorDist; // distance between anchors private int anchorNum; private int[] anchorOffset; private int[] anchorRank; private final int[] ftab = new int[66049]; private final int[] bucketRanked = new int[66049]; private final int[] runningOrder = new int[257]; private final int[] lcpAux = new int[1 + MAX_TRESH]; private int lcp; private int cmpLeft; private int cmpDone; private int aux; private int auxWritten; private int stackSize; private Node[] stack; private int start; /** * If true, {@link #buildSuffixArray(int[], int, int)} uses a copy of the input so it is left intact. */ private final boolean preserveInput; public DeepShallow() { preserveInput = true; } public DeepShallow(boolean preserveInput) { this.preserveInput = preserveInput; } /** * {@inheritDoc} *

* Additional constraints enforced by Deep-Shallow algorithm: *

    *
  • non-negative (≥0) symbols in the input
  • *
  • maximal symbol value < 256
  • *
  • input.lengthstart + length if {@link #preserveInput} is true
  • *
  • input.lengthstart + length + {@link #OVERSHOOT} if {@link #preserveInput} is false
  • *
  • length ≥ 2
  • *
*/ @Override public int[] buildSuffixArray(int[] input, int start, int length) { Tools.assertAlways(input.length >= start + length, "Input array is too short"); MinMax mm = Tools.minmax(input, start, length); Tools.assertAlways(mm.min >= 0, "input must not be negative"); Tools.assertAlways(mm.max < 256, "max alphabet size is 256"); lcp = 1; stack = new Node[length]; this.start = start; if (preserveInput) { this.start = 0; text = new int[length + OVERSHOOT]; System.arraycopy(input, start, text, 0, length); } else { Tools.assertAlways(input.length >= start + length + OVERSHOOT, "Input array length must have a trailing space of at least " + OVERSHOOT + " bytes."); text = input; } for (int i = length; i < length + OVERSHOOT; i++) { text[this.start + i] = 0; } textSize = length; suffixArray = new int[length]; int i, j, ss, sb, k, c1, c2, numQSorted = 0; boolean[] bigDone = new boolean[257]; int[] copyStart = new int[257]; int[] copyEnd = new int[257]; // ------ init array containing positions of anchors if (anchorDist == 0) { anchorNum = 0; } else { anchorNum = 2 + (length - 1) / anchorDist; // see comment for helped_sort() anchorRank = new int[anchorNum]; anchorOffset = new int[anchorNum]; for (i = 0; i < anchorNum; i++) { anchorRank[i] = -1; // pos of anchors is initially unknown anchorOffset[i] = anchorDist; // maximum possible value } } // ---------- init ftab ------------------ // at first, clear values in ftab for (i = 0; i < 66049; i++) ftab[i] = 0; c1 = text[this.start + 0]; for (i = 1; i <= textSize; i++) { c2 = text[this.start + i]; ftab[(c1 << 8) + c2]++; c1 = c2; } for (i = 1; i < 66049; i++) ftab[i] += ftab[i - 1]; // -------- sort suffixes considering only the first two chars c1 = text[this.start + 0]; for (i = 0; i < textSize; i++) { c2 = text[this.start + i + 1]; j = (c1 << 8) + c2; c1 = c2; ftab[j]--; suffixArray[ftab[j]] = i; } /* decide on the running order */ calculateRunningOrder(); for (i = 0; i < 257; i++) { bigDone[i] = false; } /* Really do the suffix sorting */ for (i = 0; i <= 256; i++) { /*-- Process big buckets, starting with the least full. --*/ ss = runningOrder[i]; /*-- Complete the big bucket [ss] by sorting any unsorted small buckets [ss, j]. Hopefully previous pointer-scanning phases have already completed many of the small buckets [ss, j], so we don't have to sort them at all. --*/ for (j = 0; j <= 256; j++) { if (j != ss) { sb = (ss << 8) + j; if ((ftab[sb] & SETMASK) == 0) { int lo = ftab[sb] & CLEARMASK; int hi = (ftab[sb + 1] & CLEARMASK) - 1; if (hi > lo) { shallowSort(lo, hi - lo + 1); numQSorted += (hi - lo + 1); } } ftab[sb] |= SETMASK; } } { for (j = 0; j <= 256; j++) { copyStart[j] = ftab[(j << 8) + ss] & CLEARMASK; copyEnd[j] = (ftab[(j << 8) + ss + 1] & CLEARMASK) - 1; } // take care of the virtual -1 char in position textSize+1 if (ss == 0) { k = textSize - 1; c1 = text[this.start + k]; if (!bigDone[c1]) suffixArray[copyStart[c1]++] = k; } for (j = ftab[ss << 8] & CLEARMASK; j < copyStart[ss]; j++) { k = suffixArray[j] - 1; if (k < 0) continue; c1 = text[this.start + k]; if (!bigDone[c1]) suffixArray[copyStart[c1]++] = k; } for (j = (ftab[(ss + 1) << 8] & CLEARMASK) - 1; j > copyEnd[ss]; j--) { k = suffixArray[j] - 1; if (k < 0) continue; c1 = text[this.start + k]; if (!bigDone[c1]) suffixArray[copyEnd[c1]--] = k; } } for (j = 0; j <= 256; j++) ftab[(j << 8) + ss] |= SETMASK; bigDone[ss] = true; }// endfor return suffixArray; } /** * This is the multikey quicksort from bentley-sedgewick modified so that it stops recursion when depth reaches * {@link #SHALLOW_LIMIT} (that is when two or more suffixes have {@link #SHALLOW_LIMIT} chars in common). */ private void shallowSort(int a, int n) { // call multikey quicksort // skip 2 chars since suffixes come from the same bucket shallowMkq32(a, n, 2); } /** * recursive multikey quicksort from Bentley-Sedgewick. *

* Stops when text_depth reaches {@link #SHALLOW_LIMIT} that is when we have found that the current set of strings * have {@link #SHALLOW_LIMIT} chars in common */ private void shallowMkq32(int a, int n, int text_depth) { int partval, val; int pa = 0, pb = 0, pc = 0, pd = 0, pl = 0, pm = 0, pn = 0;// pointers int d, r; int next_depth;// text pointer boolean repeatFlag = true; // ---- On small arrays use insertions sort if (n < MK_QS_TRESH) { shallowInssortLcp(a, n, text_depth); return; } // ----------- choose pivot -------------- while (repeatFlag) { repeatFlag = false; pl = a; pm = a + (n / 2); pn = a + (n - 1); if (n > 30) { // On big arrays, pseudomedian of 9 d = (n / 8); pl = med3(pl, pl + d, pl + 2 * d, text_depth); pm = med3(pm - d, pm, pm + d, text_depth); pn = med3(pn - 2 * d, pn - d, pn, text_depth); } pm = med3(pl, pm, pn, text_depth); swap2(a, pm); partval = ptr2char32(a, text_depth); pa = pb = a + 1; pc = pd = a + n - 1; // -------- partition ----------------- for (; ; ) { while (pb <= pc && (val = ptr2char32(pb, text_depth)) <= partval) { if (val == partval) { swap2(pa, pb); pa++; } pb++; } while (pb <= pc && (val = ptr2char32(pc, text_depth)) >= partval) { if (val == partval) { swap2(pc, pd); pd--; } pc--; } if (pb > pc) break; swap2(pb, pc); pb++; pc--; } if (pa > pd) { // all values were equal to partval: make it simpler if ((next_depth = text_depth + 4) >= SHALLOW_LIMIT) { helpedSort(a, n, next_depth); return; } else { text_depth = next_depth; repeatFlag = true; } } } // partition a[] into the values smaller, equal, and larger that partval pn = a + n; r = min(pa - a, pb - pa); vecswap2(a, pb - r, r); r = min(pd - pc, pn - pd - 1); vecswap2(pb, pn - r, r); // --- sort smaller strings ------- if ((r = pb - pa) > 1) shallowMkq32(a, r, text_depth); // --- sort strings starting with partval ----- if ((next_depth = text_depth + 4) < SHALLOW_LIMIT) shallowMkq32(a + r, pa - pd + n - 1, next_depth); else helpedSort(a + r, pa - pd + n - 1, next_depth); if ((r = pd - pc) > 1) shallowMkq32(a + n - r, r, text_depth); } private void vecswap2(int a, int b, int n) { while (n-- > 0) { int t = suffixArray[a]; suffixArray[a++] = suffixArray[b]; suffixArray[b++] = t; } } private static int min(int i, int j) { return i < j ? i : j; } /** * this is the insertion sort routine called by multikey-quicksort for sorting small groups. During insertion sort * the comparisons are done calling cmp_unrolled_shallow_lcp() and two strings are equal if the coincides for * SHALLOW_LIMIT characters. After this first phase we sort groups of "equal_string" using helped_sort(). *

*/ private void shallowInssortLcp(int a, int n, int text_depth) { int i, j, j1, lcp_new, r, ai, lcpi; int cmp_from_limit; int text_depth_ai;// pointer // --------- initialize ---------------- lcpAux[0] = -1; // set lcp[-1] = -1 for (i = 0; i < n; i++) { lcpAux[lcp + i] = 0; } cmp_from_limit = SHALLOW_LIMIT - text_depth; // ----- start insertion sort ----------- for (i = 1; i < n; i++) { ai = suffixArray[a + i]; lcpi = 0; text_depth_ai = ai + text_depth; j = i; j1 = j - 1; // j1 is a shorhand for j-1 while (true) { // ------ compare ai with a[j-1] -------- cmpLeft = cmp_from_limit - lcpi; r = cmpUnrolledShallowLcp(lcpi + suffixArray[a + j1] + text_depth, lcpi + text_depth_ai); lcp_new = cmp_from_limit - cmpLeft; // lcp between ai and a[j1] assert (r != 0 || lcp_new >= cmp_from_limit); if (r <= 0) { // we have a[j-1] <= ai lcpAux[lcp + j1] = lcp_new; // ai will be written in a[j]; update // lcp[j-1] break; } // --- we have a[j-1]>ai. a[j-1] and maybe other will be moved down // --- use lcp to move down as many elements of a[] as possible lcpi = lcp_new; do { suffixArray[a + j] = suffixArray[a + j1]; // move down a[j-1] lcpAux[lcp + j] = lcpAux[lcp + j1]; // move down lcp[j-1] j = j1; j1--; // update j and j1=j-1 } while (lcpi < lcpAux[lcp + j1]); // recall that lcp[-1]=-1 if (lcpi > lcpAux[lcp + j1]) break; // ai will be written in position j // if we get here lcpi==lcp[j1]: we will compare them at next iteration } // end for(j=i ... suffixArray[a + j] = ai; lcpAux[lcp + j] = lcpi; } // end for(i=1 ... // ----- done with insertion sort. now sort groups of equal strings for (i = 0; i < n - 1; i = j + 1) { for (j = i; j < n; j++) if (lcpAux[lcp + j] < cmp_from_limit) break; if (j - i > 0) helpedSort(a + i, j - i + 1, SHALLOW_LIMIT); } } /** * Function to compare two strings originating from the *b1 and *b2 The size of the unrolled loop must be at most * equal to the costant CMP_OVERSHOOT defined in common.h When the function is called cmpLeft must contain the * maximum number of comparisons the algorithm can do before returning 0 (equal strings) At exit cmpLeft has been * decreased by the # of comparisons done */ private int cmpUnrolledShallowLcp(int b1, int b2) { int c1, c2; // execute blocks of 16 comparisons until a difference // is found or we run out of the string do { // 1 c1 = text[this.start + b1]; c2 = text[this.start + b2]; if (c1 != c2) { return c1 - c2; } b1++; b2++; // 2 c1 = text[this.start + b1]; c2 = text[this.start + b2]; if (c1 != c2) { cmpLeft -= 1; return c1 - c2; } b1++; b2++; // 3 c1 = text[this.start + b1]; c2 = text[this.start + b2]; if (c1 != c2) { cmpLeft -= 2; return c1 - c2; } b1++; b2++; // 4 c1 = text[this.start + b1]; c2 = text[this.start + b2]; if (c1 != c2) { cmpLeft -= 3; return c1 - c2; } b1++; b2++; // 5 c1 = text[this.start + b1]; c2 = text[this.start + b2]; if (c1 != c2) { cmpLeft -= 4; return c1 - c2; } b1++; b2++; // 6 c1 = text[this.start + b1]; c2 = text[this.start + b2]; if (c1 != c2) { cmpLeft -= 5; return c1 - c2; } b1++; b2++; // 7 c1 = text[this.start + b1]; c2 = text[this.start + b2]; if (c1 != c2) { cmpLeft -= 6; return c1 - c2; } b1++; b2++; // 8 c1 = text[this.start + b1]; c2 = text[this.start + b2]; if (c1 != c2) { cmpLeft -= 7; return c1 - c2; } b1++; b2++; // 9 c1 = text[this.start + b1]; c2 = text[this.start + b2]; if (c1 != c2) { cmpLeft -= 8; return c1 - c2; } b1++; b2++; // 10 c1 = text[this.start + b1]; c2 = text[this.start + b2]; if (c1 != c2) { cmpLeft -= 9; return c1 - c2; } b1++; b2++; // 11 c1 = text[this.start + b1]; c2 = text[this.start + b2]; if (c1 != c2) { cmpLeft -= 10; return c1 - c2; } b1++; b2++; // 12 c1 = text[this.start + b1]; c2 = text[this.start + b2]; if (c1 != c2) { cmpLeft -= 11; return c1 - c2; } b1++; b2++; // 13 c1 = text[this.start + b1]; c2 = text[this.start + b2]; if (c1 != c2) { cmpLeft -= 12; return c1 - c2; } b1++; b2++; // 14 c1 = text[this.start + b1]; c2 = text[this.start + b2]; if (c1 != c2) { cmpLeft -= 13; return c1 - c2; } b1++; b2++; // 15 c1 = text[this.start + b1]; c2 = text[this.start + b2]; if (c1 != c2) { cmpLeft -= 14; return c1 - c2; } b1++; b2++; // 16 c1 = text[this.start + b1]; c2 = text[this.start + b2]; if (c1 != c2) { cmpLeft -= 15; return c1 - c2; } b1++; b2++; // if we have done enough comparisons the strings are considered equal cmpLeft -= 16; if (cmpLeft <= 0) return 0; // assert( b1 0) { // anchor <= a[i] < (sorted suffix) if (curr_sb != getSmallBucket(text_pos + diff)) { if (diff < min_forw_offset) { min_forw_offset = diff; best_forw_anchor = anchor; forw_anchor_index = i; } } else { // the sorted suffix belongs to the same bucket of a[0]..a[n-1] if (diff < min_forw_offset_buc) { min_forw_offset_buc = diff; best_forw_anchor_buc = anchor; forw_anchor_index_buc = i; } } } else { // diff<0 => anchor <= (sorted suffix) < a[i] if (diff > max_back_offset) { max_back_offset = diff; best_back_anchor = anchor; back_anchor_index = i; } // try to find a sorted suffix > a[i] by looking at next anchor aoffset = anchorOffset[++anchor]; if (aoffset < anchorDist) { diff = anchorDist + aoffset - toffset; assert (diff > 0); if (curr_sb != getSmallBucket(text_pos + diff)) { if (diff < min_forw_offset) { min_forw_offset = diff; best_forw_anchor = anchor; forw_anchor_index = i; } } else { if (diff < min_forw_offset_buc) { min_forw_offset_buc = diff; best_forw_anchor_buc = anchor; forw_anchor_index_buc = i; } } } } } } // ------ if forward anchor_sort is possible, do it! -------- if (best_forw_anchor >= 0 && min_forw_offset < depth - 1) { anchor_pos = suffixArray[a + forw_anchor_index] + min_forw_offset; anchor_rank = anchorRank[best_forw_anchor]; generalAnchorSort(a, n, anchor_pos, anchor_rank, min_forw_offset); if (anchorDist > 0) updateAnchors(a, n); return; } boolean fail = false; if (best_back_anchor >= 0) { int T0, Ti;// text pointers int j; // make sure that the offset is legal for all a[i] for (i = 0; i < n; i++) { if (suffixArray[a + i] + max_back_offset < 0) fail = true; // goto fail; // illegal offset, give up } // make sure that a[0] .. a[n-1] are preceded by the same substring T0 = suffixArray[a]; for (i = 1; i < n; i++) { Ti = suffixArray[a + i]; for (j = max_back_offset; j <= -1; j++) if (text[this.start + T0 + j] != text[this.start + Ti + j]) fail = true; // goto fail; // mismatch, give up } if (!fail) { // backward anchor sorting is possible anchor_pos = suffixArray[a + back_anchor_index] + max_back_offset; anchor_rank = anchorRank[best_back_anchor]; generalAnchorSort(a, n, anchor_pos, anchor_rank, max_back_offset); if (anchorDist > 0) updateAnchors(a, n); return; } } if (fail) { if (best_forw_anchor_buc >= 0 && min_forw_offset_buc < depth - 1) { int equal = 0, lower = 0, upper = 0; anchor_pos = suffixArray[a + forw_anchor_index_buc] + min_forw_offset_buc; anchor_rank = anchorRank[best_forw_anchor_buc]; // establish how many suffixes can be sorted using anchor_sort() SplitGroupResult res = splitGroup(a, n, depth, min_forw_offset_buc, forw_anchor_index_buc, lower); equal = res.equal; lower = res.lower; if (equal == n) { generalAnchorSort(a, n, anchor_pos, anchor_rank, min_forw_offset_buc); } else { // -- a[0] ... a[n-1] are split into 3 groups: lower, equal, upper upper = n - equal - lower; // printf("Warning! lo=%d eq=%d up=%d a=%x\n",lower,equal,upper,(int)a); // sort the equal group if (equal > 1) generalAnchorSort(a + lower, equal, anchor_pos, anchor_rank, min_forw_offset_buc); // sort upper and lower groups using deep_sort if (lower > 1) pseudoOrDeepSort(a, lower, depth); if (upper > 1) pseudoOrDeepSort(a + lower + equal, upper, depth); } // end if(equal==n) ... else if (anchorDist > 0) updateAnchors(a, n); return; } // end hard case } // --------------------------------------------------------------- // If we get here it means that everything failed // In this case we simply deep_sort a[0] ... a[n-1] // --------------------------------------------------------------- pseudoOrDeepSort(a, n, depth); } /** * This function takes as input an array a[0] .. a[n-1] of suffixes which share the first "depth" chars. "pivot" in * an index in 0..n-1 and offset and integer>0. The function splits a[0] .. a[n-1] into 3 groups: first the suffixes * which are smaller than a[pivot], then those which are equal to a[pivot] and finally those which are greater than * a[pivot]. Here, smaller, equal, larger refer to a lexicographic ordering limited to the first depth+offest chars * (since the first depth chars are equal we only look at the chars in position depth, depth+1, ... depth+offset-1). * The function returns the number "num" of suffixes equal to a[pivot], and stores in *first the first of these * suffixes. So at the end the smaller suffixes are in a[0] ... a[first-1], the equal suffixes in a[first] ... * a[first+num-1], the larger suffixes in a[first+num] ... a[n-1] The splitting is done using a modified mkq() */ private SplitGroupResult splitGroup(int a, int n, int depth, int offset, int pivot, int first) { int r, partval; int pa, pb, pc, pd, pa_old, pd_old;// pointers int pivot_pos; int text_depth, text_limit;// pointers // --------- initialization ------------------------------------ pivot_pos = suffixArray[a + pivot]; // starting position in T[] of pivot text_depth = depth; text_limit = text_depth + offset; // ------------------------------------------------------------- // In the following for() loop: // [pa ... pd] is the current working region, // pb moves from pa towards pd // pc moves from pd towards pa // ------------------------------------------------------------- pa = a; pd = a + n - 1; for (; pa != pd && (text_depth < text_limit); text_depth++) { // ------ the pivot char is text[this.start + pivot_pos+depth] where // depth = text_depth-text. This is text_depth[pivot_pos] partval = text[this.start + text_depth + pivot_pos]; // ----- partition ------------ pb = pa_old = pa; pc = pd_old = pd; for (; ; ) { while (pb <= pc && (r = ptr2char(pb, text_depth) - partval) <= 0) { if (r == 0) { swap2(pa, pb); pa++; } pb++; } while (pb <= pc && (r = ptr2char(pc, text_depth) - partval) >= 0) { if (r == 0) { swap2(pc, pd); pd--; } pc--; } if (pb > pc) break; swap2(pb, pc); pb++; pc--; } r = min(pa - pa_old, pb - pa); vecswap2(pa_old, pb - r, r); r = min(pd - pc, pd_old - pd); vecswap2(pb, pd_old + 1 - r, r); // ------ compute new boundaries ----- pa = pa_old + (pb - pa); // there are pb-pa chars < partval pd = pd_old - (pd - pc); // there are pd-pc chars > partval } first = pa - a; // index in a[] of the first suf. equal to pivot // return pd-pa+1; // return number of suffixes equal to pivot return new SplitGroupResult(pd - pa + 1, first); } /** * given a SORTED array of suffixes a[0] .. a[n-1] updates anchorRank[] and anchorOffset[] */ private void updateAnchors(int a, int n) { int i, anchor, toffset, aoffset, text_pos; for (i = 0; i < n; i++) { text_pos = suffixArray[a + i]; // get anchor preceeding text_pos=a[i] anchor = text_pos / anchorDist; toffset = text_pos % anchorDist; // distance of a[i] from anchor aoffset = anchorOffset[anchor]; // dist of sorted suf from anchor if (toffset < aoffset) { anchorOffset[anchor] = toffset; anchorRank[anchor] = a + i; } } } /** * This routines sorts a[0] ... a[n-1] using the fact that in their common prefix, after offset characters, there is * a suffix whose rank is known. In this routine we call this suffix anchor (and we denote its position and rank * with anchor_pos and anchor_rank respectively) but it is not necessarily an anchor (=does not necessarily starts * at position multiple of anchorDist) since this function is called by pseudo_anchor_sort(). The routine works by * scanning the suffixes before and after the anchor in order to find (and mark) those which are suffixes of a[0] * ... a[n-1]. After that, the ordering of a[0] ... a[n-1] is derived with a sigle scan of the marked * suffixes.******************************************************************* */ private void generalAnchorSort(int a, int n, int anchor_pos, int anchor_rank, int offset) { int sb, lo, hi; int curr_lo, curr_hi, to_be_found, i, j; int item; int ris; // void *ris; /* ---------- get bucket of anchor ---------- */ sb = getSmallBucket(anchor_pos); lo = bucketFirst(sb); hi = bucketLast(sb); // ------ sort pointers a[0] ... a[n-1] as plain integers // qsort(a, n, sizeof(Int32), integer_cmp); Arrays.sort(suffixArray, a, a + n); // ------------------------------------------------------------------ // now we scan the bucket containing the anchor in search of suffixes // corresponding to the ones we have to sort. When we find one of // such suffixes we mark it. We go on untill n sfx's have been marked // ------------------------------------------------------------------ curr_hi = curr_lo = anchor_rank; mark(curr_lo); // scan suffixes preceeding and following the anchor for (to_be_found = n - 1; to_be_found > 0; ) { // invariant: the next positions to check are curr_lo-1 and curr_hi+1 assert (curr_lo > lo || curr_hi < hi); while (curr_lo > lo) { item = suffixArray[--curr_lo] - offset; ris = Arrays.binarySearch(suffixArray, a, a + n, item); // ris = bsearch(&item,a,n,sizeof(Int32), integer_cmp); if (ris != 0) { mark(curr_lo); to_be_found--; } else break; } while (curr_hi < hi) { item = suffixArray[++curr_hi] - offset; ris = Arrays.binarySearch(suffixArray, a, a + n, item); if (ris != 0) { mark(curr_hi); to_be_found--; } else break; } } // sort a[] using the marked suffixes for (j = 0, i = curr_lo; i <= curr_hi; i++) if (isMarked(i)) { unmark(i); suffixArray[a + j++] = suffixArray[i] - offset; } } /** * */ private void unmark(int i) { suffixArray[i] &= ~MARKER; } /** * */ private boolean isMarked(int i) { return (suffixArray[i] & MARKER) != 0; } /** * */ private void mark(int i) { suffixArray[i] |= MARKER; } /** * */ private int bucketLast(int sb) { return (ftab[sb + 1] & CLEARMASK) - 1; } /** * */ private int bucketFirst(int sb) { return ftab[sb] & CLEARMASK; } /** * */ private int bucketSize(int sb) { return (ftab[sb + 1] & CLEARMASK) - (ftab[sb] & CLEARMASK); } /** * */ private int getSmallBucket(int pos) { return (text[this.start + pos] << 8) + text[this.start + pos + 1]; } /** * */ @SuppressWarnings("unused") private void pseudoOrDeepSort(int a, int n, int depth) { int offset, text_pos, sb, pseudo_anchor_pos, max_offset, size; // ------- search for a useful pseudo-anchor ------------- if (MAX_PSEUDO_ANCHOR_OFFSET > 0) { max_offset = min(depth - 1, MAX_PSEUDO_ANCHOR_OFFSET); text_pos = suffixArray[a]; for (offset = 1; offset < max_offset; offset++) { pseudo_anchor_pos = text_pos + offset; sb = getSmallBucket(pseudo_anchor_pos); // check if pseudo_anchor is in a sorted bucket if (isSortedBucket(sb)) { size = bucketSize(sb); // size of group if (size > B2G_RATIO * n) continue; // discard large groups // sort a[0] ... a[n-1] using pseudo_anchor pseudoAnchorSort(a, n, pseudo_anchor_pos, offset); return; } } } deepSort(a, n, depth); } /** * */ private boolean isSortedBucket(int sb) { return (ftab[sb] & SETMASK) != 0; } /** * routine for deep-sorting the suffixes a[0] ... a[n-1] knowing that they have a common prefix of length "depth" */ private void deepSort(int a, int n, int depth) { int blind_limit; blind_limit = textSize / BLIND_SORT_RATIO; if (n <= blind_limit) blindSsort(a, n, depth); // small_group else qsUnrolledLcp(a, n, depth, blind_limit); } /** * ternary quicksort (seward-like) with lcp information */ private void qsUnrolledLcp(int a, int n, int depth, int blind_limit) { int text_depth, text_pos_pivot;// pointers int[] stack_lo = new int[STACK_SIZE]; int[] stack_hi = new int[STACK_SIZE]; int[] stack_d = new int[STACK_SIZE]; int sp, r, r3, med; int i, j, lo, hi, ris, lcp_lo, lcp_hi; // ----- init quicksort -------------- r = sp = 0; // Pushd(0,n-1,depth); stack_lo[sp] = 0; stack_hi[sp] = n - 1; stack_d[sp] = depth; sp++; // end Pushd // ----- repeat untill stack is empty ------ while (sp > 0) { assert (sp < STACK_SIZE); // Popd(lo,hi,depth); sp--; lo = stack_lo[sp]; hi = stack_hi[sp]; depth = stack_d[sp]; // end popd text_depth = depth; // --- use shellsort for small groups if (hi - lo < blind_limit) { blindSsort(a + lo, hi - lo + 1, depth); continue; } /* * Random partitioning. Guidance for the magic constants 7621 and 32768 is * taken from Sedgewick's algorithms book, chapter 35. */ r = ((r * 7621) + 1) % 32768; r3 = r % 3; if (r3 == 0) med = lo; else if (r3 == 1) med = (lo + hi) >> 1; else med = hi; // --- partition ---- swap(med, hi, a); // put the pivot at the right-end text_pos_pivot = text_depth + suffixArray[a + hi]; i = lo - 1; j = hi; lcp_lo = lcp_hi = Integer.MAX_VALUE; while (true) { while (++i < hi) { ris = cmpUnrolledLcp(text_depth + suffixArray[a + i], text_pos_pivot); if (ris > 0) { if (cmpDone < lcp_hi) lcp_hi = cmpDone; break; } else if (cmpDone < lcp_lo) lcp_lo = cmpDone; } while (--j > lo) { ris = cmpUnrolledLcp(text_depth + suffixArray[a + j], text_pos_pivot); if (ris < 0) { if (cmpDone < lcp_lo) lcp_lo = cmpDone; break; } else if (cmpDone < lcp_hi) lcp_hi = cmpDone; } if (i >= j) break; swap(i, j, a); } swap(i, hi, a); // put pivot at the middle // --------- insert subproblems in stack; smallest last if (i - lo < hi - i) { // Pushd(i + 1, hi, depth + lcp_hi); stack_lo[sp] = i + 1; stack_hi[sp] = hi; stack_d[sp] = depth + lcp_hi; sp++; // end pushd if (i - lo > 1) { // Pushd(lo, i - 1, depth + lcp_lo); stack_lo[sp] = lo; stack_hi[sp] = i - 1; stack_d[sp] = depth + lcp_lo; sp++; // end push } } else { // Pushd(lo, i - 1, depth + lcp_lo); stack_lo[sp] = lo; stack_hi[sp] = i - 1; stack_d[sp] = depth + lcp_lo; sp++; // end pushd if (hi - i > 1) { // Pushd(i + 1, hi, depth + lcp_hi); stack_lo[sp] = i + 1; stack_hi[sp] = hi; stack_d[sp] = depth + lcp_hi; sp++; // end pushd } } } } /** * Function to compare two strings originating from the *b1 and *b2 The size of the unrolled loop must be at most * equal to the costant CMP_OVERSHOOT defined in common.h the function return the result of the comparison (+ or -) * and writes in cmpDone the number of successfull comparisons done */ private int cmpUnrolledLcp(int b1, int b2) { int c1, c2; cmpDone = 0; // execute blocks of 16 comparisons untill a difference // is found or we run out of the string do { // 1 c1 = text[this.start + b1]; c2 = text[this.start + b2]; if (c1 != c2) { return (c1 - c2); } b1++; b2++; // 2 c1 = text[this.start + b1]; c2 = text[this.start + b2]; if (c1 != c2) { cmpDone += 1; return (c1 - c2); } b1++; b2++; // 3 c1 = text[this.start + b1]; c2 = text[this.start + b2]; if (c1 != c2) { cmpDone += 2; return (c1 - c2); } b1++; b2++; // 4 c1 = text[this.start + b1]; c2 = text[this.start + b2]; if (c1 != c2) { cmpDone += 3; return (c1 - c2); } b1++; b2++; // 5 c1 = text[this.start + b1]; c2 = text[this.start + b2]; if (c1 != c2) { cmpDone += 4; return (c1 - c2); } b1++; b2++; // 6 c1 = text[this.start + b1]; c2 = text[this.start + b2]; if (c1 != c2) { cmpDone += 5; return (c1 - c2); } b1++; b2++; // 7 c1 = text[this.start + b1]; c2 = text[this.start + b2]; if (c1 != c2) { cmpDone += 6; return (c1 - c2); } b1++; b2++; // 8 c1 = text[this.start + b1]; c2 = text[this.start + b2]; if (c1 != c2) { cmpDone += 7; return (c1 - c2); } b1++; b2++; // 9 c1 = text[this.start + b1]; c2 = text[this.start + b2]; if (c1 != c2) { cmpDone += 8; return (c1 - c2); } b1++; b2++; // 10 c1 = text[this.start + b1]; c2 = text[this.start + b2]; if (c1 != c2) { cmpDone += 9; return (c1 - c2); } b1++; b2++; // 11 c1 = text[this.start + b1]; c2 = text[this.start + b2]; if (c1 != c2) { cmpDone += 10; return (c1 - c2); } b1++; b2++; // 12 c1 = text[this.start + b1]; c2 = text[this.start + b2]; if (c1 != c2) { cmpDone += 11; return (c1 - c2); } b1++; b2++; // 13 c1 = text[this.start + b1]; c2 = text[this.start + b2]; if (c1 != c2) { cmpDone += 12; return (c1 - c2); } b1++; b2++; // 14 c1 = text[this.start + b1]; c2 = text[this.start + b2]; if (c1 != c2) { cmpDone += 13; return (c1 - c2); } b1++; b2++; // 15 c1 = text[this.start + b1]; c2 = text[this.start + b2]; if (c1 != c2) { cmpDone += 14; return (c1 - c2); } b1++; b2++; // 16 c1 = text[this.start + b1]; c2 = text[this.start + b2]; if (c1 != c2) { cmpDone += 15; return (c1 - c2); } b1++; b2++; cmpDone += 16; } while (b1 < textSize && b2 < textSize); return b2 - b1; } /** * */ private void swap(int i, int j, int a) { int tmp = suffixArray[a + i]; suffixArray[a + i] = suffixArray[a + j]; suffixArray[a + j] = tmp; } /** * routine for deep-sorting the suffixes a[0] ... a[n-1] knowing that they have a common prefix of length "depth" */ private void blindSsort(int a, int n, int depth) { int i, j, aj, lcp; Node nh, root, h; // ---- sort suffixes in order of increasing length // qsort(a, n, sizeof(Int32), neg_integer_cmp); Arrays.sort(suffixArray, a, a + n); for (int left = 0, right = n - 1; left < right; left++, right--) { // exchange the first and last int temp = suffixArray[a + left]; suffixArray[a + left] = suffixArray[a + right]; suffixArray[a + right] = temp; } // --- skip suffixes which have already reached the end-of-text for (j = 0; j < n; j++) if (suffixArray[a + j] + depth < textSize) break; if (j >= n - 1) return; // everything is already sorted! // ------ init stack ------- // stack = (node **) malloc(n*sizeof(node *)); // ------- init root with the first unsorted suffix nh = new Node(); nh.skip = -1; nh.right = null; // nh.down = (void *) a[j]; nh.downInt = suffixArray[a + j]; root = nh; // ------- insert suffixes a[j+1] ... a[n-1] for (i = j + 1; i < n; i++) { h = findCompanion(root, suffixArray[a + i]); aj = h.downInt; lcp = compareSuffixes(aj, suffixArray[a + i], depth); insertSuffix(root, suffixArray[a + i], lcp, text[this.start + aj + lcp]); } // ---- traverse the trie and get suffixes in lexicographic order aux = a; auxWritten = j; traverseTrie(root); } /** * this procedures traverse the trie in depth first order so that the suffixes (stored in the leaf) are recovered in * lexicographic order */ private void traverseTrie(Node h) { Node p, nextp; if (h.skip < 0) suffixArray[aux + auxWritten++] = h.downInt; else { p = h.down; do { nextp = p.right; if (nextp != null) { // if there are 2 nodes with equal keys // they must be considered in inverted order if (nextp.key == p.key) { traverseTrie(nextp); traverseTrie(p); p = nextp.right; continue; } } traverseTrie(p); p = nextp; } while (p != null); } } /** * insert a suffix in the trie rooted at *p. we know that the trie already contains a string which share the first n * chars with suf */ private void insertSuffix(Node h, int suf, int n, int mmchar) { int c, s; Node p, pp; s = suf; // --------- insert a new node before node *h if necessary if (h.skip != n) { p = new Node(); p.key = mmchar; p.skip = h.skip; // p inherits skip and children of *h p.down = h.down; p.downInt = h.downInt; p.right = null; h.skip = n; h.down = p; // now *h has p as the only child } // -------- search the position of s[n] among *h offsprings c = text[this.start + s + n]; pp = h.down; while (pp != null) { if (pp.key >= c) break; pp = pp.right; } // ------- insert new node containing suf p = new Node(); p.skip = -1; p.key = c; p.right = pp; pp = p; p.downInt = suf; return; } /** * this function returns the lcp between suf1 and suf2 (that is returns n such that suf1[n]!=suf2[n] but * suf1[i]==suf2[i] for i=0..n-1 However, it is possible that suf1 is a prefix of suf2 (not vice-versa because of * the initial sorting of suffixes in order of descreasing length) in this case the function returns * n=length(suf1)-1. So in this case suf1[n]==suf2[n] (and suf1[n+1] does not exists). */ private int compareSuffixes(int suf1, int suf2, int depth) { int limit; int s1, s2; s1 = depth + suf1; s2 = depth + suf2; limit = textSize - suf1 - depth; return depth + getLcpUnrolled(s1, s2, limit); } /** * */ private int getLcpUnrolled(int b1, int b2, int cmp_limit) { int cmp2do; int c1, c2; // execute blocks of 16 comparisons untill a difference // is found or we reach cmp_limit comparisons cmp2do = cmp_limit; do { // 1 c1 = text[this.start + b1]; c2 = text[this.start + b2]; if (c1 != c2) { break; } b1++; b2++; // 2 c1 = text[this.start + b1]; c2 = text[this.start + b2]; if (c1 != c2) { cmp2do -= 1; break; } b1++; b2++; // 3 c1 = text[this.start + b1]; c2 = text[this.start + b2]; if (c1 != c2) { cmp2do -= 2; break; } b1++; b2++; // 4 c1 = text[this.start + b1]; c2 = text[this.start + b2]; if (c1 != c2) { cmp2do -= 3; break; } b1++; b2++; // 5 c1 = text[this.start + b1]; c2 = text[this.start + b2]; if (c1 != c2) { cmp2do -= 4; break; } b1++; b2++; // 6 c1 = text[this.start + b1]; c2 = text[this.start + b2]; if (c1 != c2) { cmp2do -= 5; break; } b1++; b2++; // 7 c1 = text[this.start + b1]; c2 = text[this.start + b2]; if (c1 != c2) { cmp2do -= 6; break; } b1++; b2++; // 8 c1 = text[this.start + b1]; c2 = text[this.start + b2]; if (c1 != c2) { cmp2do -= 7; break; } b1++; b2++; // 9 c1 = text[this.start + b1]; c2 = text[this.start + b2]; if (c1 != c2) { cmp2do -= 8; break; } b1++; b2++; // 10 c1 = text[this.start + b1]; c2 = text[this.start + b2]; if (c1 != c2) { cmp2do -= 9; break; } b1++; b2++; // 11 c1 = text[this.start + b1]; c2 = text[this.start + b2]; if (c1 != c2) { cmp2do -= 10; break; } b1++; b2++; // 12 c1 = text[this.start + b1]; c2 = text[this.start + b2]; if (c1 != c2) { cmp2do -= 11; break; } b1++; b2++; // 13 c1 = text[this.start + b1]; c2 = text[this.start + b2]; if (c1 != c2) { cmp2do -= 12; break; } b1++; b2++; // 14 c1 = text[this.start + b1]; c2 = text[this.start + b2]; if (c1 != c2) { cmp2do -= 13; break; } b1++; b2++; // 15 c1 = text[this.start + b1]; c2 = text[this.start + b2]; if (c1 != c2) { cmp2do -= 14; break; } b1++; b2++; // 16 c1 = text[this.start + b1]; c2 = text[this.start + b2]; if (c1 != c2) { cmp2do -= 15; break; } b1++; b2++; cmp2do -= 16; } while (cmp2do > 0); if (cmp_limit - cmp2do < cmp_limit) return cmp_limit - cmp2do; return cmp_limit - 1; } /** * this function traverses the trie rooted at head following the string s. Returns the leaf "corresponding" to the * string s */ private Node findCompanion(Node head, int s) { int c; Node p; int t; stackSize = 0; // init stack while (head.skip >= 0) { stack[stackSize++] = head; t = head.skip; if (s + t >= textSize) // s[t] does not exist: mismatch return getLeaf(head); c = text[this.start + s + t]; p = head.down; boolean repeat = true; while (repeat) { if (c == p.key) { // found branch corresponding to c head = p; repeat = false; } else if (c < p.key) // no branch corresponding to c: mismatch { return getLeaf(head); } if (repeat && (p = (p.right)) == null) // no other branches: mismatch { return getLeaf(head); } } } stack[stackSize++] = head; return head; } /** * this function returns a leaf below "head". any leaf will do for the algorithm: we take the easiest to reach */ private Node getLeaf(Node head) { Tools.assertAlways(head.skip >= 0, ""); do { head = head.down; } while (head.skip >= 0); return head; } /** * */ @SuppressWarnings("unused") private void pseudoAnchorSort(int a, int n, int pseudo_anchor_pos, int offset) { int pseudo_anchor_rank; // ---------- compute rank ------------ if (UPDATE_ANCHOR_RANKS && anchorDist > 0) pseudo_anchor_rank = getRankUpdateAnchors(pseudo_anchor_pos); else pseudo_anchor_rank = getRank(pseudo_anchor_pos); // ---------- check rank -------------- assert (suffixArray[pseudo_anchor_rank] == pseudo_anchor_pos); // ---------- do the sorting ---------- generalAnchorSort(a, n, pseudo_anchor_pos, pseudo_anchor_rank, offset); } /** * compute the rank of the suffix starting at pos. It is required that the suffix is in an already sorted bucket */ private int getRank(int pos) { int sb, lo, hi, j; sb = getSmallBucket(pos); if (!isSortedBucket(sb)) { throw new RuntimeException("Illegal call to get_rank! (get_rank1)"); } lo = bucketFirst(sb); hi = bucketLast(sb); for (j = lo; j <= hi; j++) if (suffixArray[j] == pos) return j; throw new RuntimeException("Illegal call to get_rank! (get_rank2)"); } /** * compute the rank of the suffix starting at pos. At the same time check if the rank of the suffixes in the bucket * containing pos can be used to update some entries in anchorOffset[] and anchorRank[] It is required that the * suffix is in an already sorted bucket */ private int getRankUpdateAnchors(int pos) { int sb, lo, hi, j, toffset, aoffset, anchor, rank; // --- get bucket and verify it is a sorted one sb = getSmallBucket(pos); if (!(isSortedBucket(sb))) { throw new RuntimeException("Illegal call to get_rank! (get_rank_update_anchors)"); } // --- if the bucket has been already ranked just compute rank; if (bucketRanked[sb] != 0) return getRank(pos); // --- rank all the bucket bucketRanked[sb] = 1; rank = -1; lo = bucketFirst(sb); hi = bucketLast(sb); for (j = lo; j <= hi; j++) { // see if we can update an anchor toffset = suffixArray[j] % anchorDist; anchor = suffixArray[j] / anchorDist; aoffset = anchorOffset[anchor]; // dist of sorted suf from anchor if (toffset < aoffset) { anchorOffset[anchor] = toffset; anchorRank[anchor] = j; } // see if we have found the rank of pos, if so store it in rank if (suffixArray[j] == pos) { assert (rank == -1); rank = j; } } assert (rank >= 0); return rank; } private void swap2(int a, int b) { int tmp = suffixArray[a]; suffixArray[a] = suffixArray[b]; suffixArray[b] = tmp; } /* * #define ptr2char32(i) (getword32(*(i) + text_depth)) */ private int ptr2char32(int a, int depth) { return getword32(suffixArray[a] + depth); } /* * #define getword32(s) ((unsigned)( (*(s) << 24) | ((*((s)+1)) << 16) \ | ((*((s)+2)) * << 8) | (*((s)+3)) )) */ private int getword32(int s) { return text[this.start + s] << 24 | text[this.start + s + 1] << 16 | text[this.start + s + 2] << 8 | text[this.start + s + 3]; } private int ptr2char(int i, int text_depth) { return text[this.start + suffixArray[i] + text_depth]; } private int med3(int a, int b, int c, int depth) { int va = ptr2char(a, depth); int vb = ptr2char(b, depth); if (va == vb) { return a; } int vc = ptr2char(c, depth); if (vc == va || vc == vb) { return c; } return va < vb ? (vb < vc ? b : (va < vc ? c : a)) : (vb > vc ? b : (va < vc ? a : c)); } private void calculateRunningOrder() { int i, j; for (i = 0; i <= 256; i++) runningOrder[i] = i; { int vv; int h = 1; do h = 3 * h + 1; while (h <= 257); do { h = h / 3; for (i = h; i <= 256; i++) { vv = runningOrder[i]; j = i; while (bigFreq(runningOrder[j - h]) > bigFreq(vv)) { runningOrder[j] = runningOrder[j - h]; j = j - h; if (j <= (h - 1)) break; } runningOrder[j] = vv; } } while (h != 1); } } /** * */ private int bigFreq(int b) { return ftab[((b) + 1) << 8] - ftab[(b) << 8]; } public static void main(String[] args) { for (int i = 0; i < 5; i++) { System.gc(); } int size = 1000000; final Runtime rt = Runtime.getRuntime(); long before, after; Node[] nodes = new Node[size]; before = rt.totalMemory() - rt.freeMemory(); for (int i = 0; i < size; i++) { nodes[i] = new Node(); } after = rt.totalMemory() - rt.freeMemory(); double a = 1.0 * (after - before) / size; System.out.println(before + " " + after + " " + size + " " + a); } }





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