[gnudiff/f21] Importing
Ismael Olea
olea at fedoraproject.org
Thu Aug 21 15:45:49 UTC 2014
commit 31c37682fc53a5dcf01265c362c95317bfd00cf2
Author: Ismael Olea <ismael at olea.org>
Date: Thu Aug 21 17:44:12 2014 +0200
Importing
Diff.java | 940 +++++++++++++++++++++++++++++++++++++++++++++++++++++++
gnudiff-1.7.pom | 44 +++
gnudiff.spec | 78 +++++
3 files changed, 1062 insertions(+), 0 deletions(-)
---
diff --git a/Diff.java b/Diff.java
new file mode 100644
index 0000000..21227a2
--- /dev/null
+++ b/Diff.java
@@ -0,0 +1,940 @@
+/*
+ * $Log: Diff.java,v $
+ * Revision 1.15 2013/04/01 16:27:31 stuart
+ * Fix DiffPrint unified format with test cases.
+ * Begin porting some diff-2.7 features.
+ *
+ * Revision 1.14 2010/03/03 21:21:25 stuart
+ * Test new direct equivalence API
+ *
+ * Revision 1.13 2009/12/07 17:43:17 stuart
+ * Compute equiv_max for int[] ctor
+ *
+ * Revision 1.12 2009/12/07 17:34:46 stuart
+ * Ctor with int[].
+ *
+ * Revision 1.11 2009/11/15 01:11:54 stuart
+ * Diff doesn't need to be generic
+ *
+ * Revision 1.10 2009/11/15 00:54:03 stuart
+ * Update to Java 5 containers
+ *
+ * Revision 1.7 2009/01/19 03:05:26 stuart
+ * Fix StackOverflow bug with heuristic on reported by Jimmy Han.
+ *
+ * Revision 1.6 2003/03/06 22:51:32 stuart
+ * Convert to CVS
+ *
+ * Revision 1.5 2002/07/19 19:14:40 stuart
+ * fix reverseScript, make change ctor public, update docs
+ *
+ * Revision 1.4 2002/04/09 17:53:39 stuart
+ * More flexible interface for diff() function.
+ *
+ * Revision 1.3 2000/03/03 21:58:03 stuart
+ * move discard_confusing_lines and shift_boundaries to class file_data
+ *
+ * Revision 1.2 2000/03/02 16:37:38 stuart
+ * Add GPL and copyright
+ *
+ */
+package bmsi.util;
+
+import java.util.*;
+
+/** A class to compare vectors of objects. The result of comparison
+ is a list of <code>change</code> objects which form an
+ edit script. The objects compared are traditionally lines
+ of text from two files. Comparison options such as "ignore
+ whitespace" are implemented by modifying the <code>equals</code>
+ and <code>hashcode</code> methods for the objects compared.
+<p>
+ The basic algorithm is described in: </br>
+ "An O(ND) Difference Algorithm and its Variations", Eugene Myers,
+ Algorithmica Vol. 1 No. 2, 1986, p 251.
+<p>
+ This class outputs different results from GNU diff 1.15 on some
+ inputs. Our results are actually better (smaller change list, smaller
+ total size of changes), but it would be nice to know why. Perhaps
+ there is a memory overwrite bug in GNU diff 1.15.
+
+ @author Stuart D. Gathman, translated from GNU diff 1.15
+ Copyright (C) 2000 Business Management Systems, Inc.
+<p>
+ This program is free software; you can redistribute it and/or modify
+ it under the terms of the GNU General Public License as published by
+ the Free Software Foundation; either version 1, or (at your option)
+ any later version.
+<p>
+ This program is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ GNU General Public License for more details.
+<p>
+ You should have received a copy of the <a href=COPYING.txt>
+ GNU General Public License</a>
+ along with this program; if not, write to the Free Software
+ Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+
+ */
+
+public class Diff {
+
+ /** Prepare to find differences between two arrays. Each element of
+ the arrays is translated to an "equivalence number" based on
+ the result of <code>equals</code>. The original Object arrays
+ are no longer needed for computing the differences. They will
+ be needed again later to print the results of the comparison as
+ an edit script, if desired.
+ */
+ public Diff(Object[] a,Object[] b) {
+ Map<Object,Integer> h = new HashMap<Object,Integer>(a.length + b.length);
+ filevec = new file_data[] { new file_data(a,h),new file_data(b,h) };
+ }
+
+ /** Prepare to find differences between two arrays. This ctor
+ lets the caller computer equivalence numbers in any desired way.
+ For instance, two char[] can be compared by copying to int[] with
+ System.arraycopy().
+ */
+ public Diff(int[] a,int [] b) {
+ for (int i: a)
+ if (i >= equiv_max) equiv_max = i + 1;
+ for (int i: b)
+ if (i >= equiv_max) equiv_max = i + 1;
+ filevec = new file_data[] { new file_data(a),new file_data(b) };
+ }
+
+ /** 1 more than the maximum equivalence value used for this or its
+ sibling file. */
+ private int equiv_max = 1;
+
+ /** When set to true, the comparison uses a heuristic to speed it up.
+ With this heuristic, for files with a constant small density
+ of changes, the algorithm is linear in the file size. */
+ public boolean heuristic = false;
+
+ /** When set to true, the algorithm returns a guarranteed minimal
+ set of changes. This makes things slower, sometimes much slower. */
+ public boolean no_discards = false;
+
+ private int[] xvec, yvec; /* Vectors being compared. */
+ private int[] fdiag; /* Vector, indexed by diagonal, containing
+ the X coordinate of the point furthest
+ along the given diagonal in the forward
+ search of the edit matrix. */
+ private int[] bdiag; /* Vector, indexed by diagonal, containing
+ the X coordinate of the point furthest
+ along the given diagonal in the backward
+ search of the edit matrix. */
+ private int fdiagoff, bdiagoff;
+ private final file_data[] filevec;
+ private int cost;
+ /** Snakes bigger than this are considered "big". */
+ private static final int SNAKE_LIMIT = 20;
+
+ /** Find the midpoint of the shortest edit script for a specified
+ portion of the two files.
+
+ We scan from the beginnings of the files, and simultaneously from the ends,
+ doing a breadth-first search through the space of edit-sequence.
+ When the two searches meet, we have found the midpoint of the shortest
+ edit sequence.
+
+ The value returned is the number of the diagonal on which the midpoint lies.
+ The diagonal number equals the number of inserted lines minus the number
+ of deleted lines (counting only lines before the midpoint).
+ The edit cost is stored into COST; this is the total number of
+ lines inserted or deleted (counting only lines before the midpoint).
+
+ This function assumes that the first lines of the specified portions
+ of the two files do not match, and likewise that the last lines do not
+ match. The caller must trim matching lines from the beginning and end
+ of the portions it is going to specify.
+
+ Note that if we return the "wrong" diagonal value, or if
+ the value of bdiag at that diagonal is "wrong",
+ the worst this can do is cause suboptimal diff output.
+ It cannot cause incorrect diff output. */
+
+ private int diag (int xoff, int xlim, int yoff, int ylim) {
+ final int[] fd = fdiag; // Give the compiler a chance.
+ final int[] bd = bdiag; // Additional help for the compiler.
+ final int[] xv = xvec; // Still more help for the compiler.
+ final int[] yv = yvec; // And more and more . . .
+ final int dmin = xoff - ylim; // Minimum valid diagonal.
+ final int dmax = xlim - yoff; // Maximum valid diagonal.
+ final int fmid = xoff - yoff; // Center diagonal of top-down search.
+ final int bmid = xlim - ylim; // Center diagonal of bottom-up search.
+ int fmin = fmid, fmax = fmid; // Limits of top-down search.
+ int bmin = bmid, bmax = bmid; // Limits of bottom-up search.
+ /* True if southeast corner is on an odd
+ diagonal with respect to the northwest. */
+ final boolean odd = (fmid - bmid & 1) != 0;
+
+ fd[fdiagoff + fmid] = xoff;
+ bd[bdiagoff + bmid] = xlim;
+
+ for (int c = 1;; ++c)
+ {
+ int d; /* Active diagonal. */
+ boolean big_snake = false;
+
+ /* Extend the top-down search by an edit step in each diagonal. */
+ if (fmin > dmin)
+ fd[fdiagoff + --fmin - 1] = -1;
+ else
+ ++fmin;
+ if (fmax < dmax)
+ fd[fdiagoff + ++fmax + 1] = -1;
+ else
+ --fmax;
+ for (d = fmax; d >= fmin; d -= 2)
+ {
+ int x, y, oldx, tlo = fd[fdiagoff + d - 1], thi = fd[fdiagoff + d + 1];
+
+ if (tlo >= thi)
+ x = tlo + 1;
+ else
+ x = thi;
+ oldx = x;
+ y = x - d;
+ while (x < xlim && y < ylim && xv[x] == yv[y]) {
+ ++x; ++y;
+ }
+ if (x - oldx > SNAKE_LIMIT)
+ big_snake = true;
+ fd[fdiagoff + d] = x;
+ if (odd && bmin <= d && d <= bmax && bd[bdiagoff + d] <= fd[fdiagoff + d])
+ {
+ cost = 2 * c - 1;
+ return d;
+ }
+ }
+
+ /* Similar extend the bottom-up search. */
+ if (bmin > dmin)
+ bd[bdiagoff + --bmin - 1] = Integer.MAX_VALUE;
+ else
+ ++bmin;
+ if (bmax < dmax)
+ bd[bdiagoff + ++bmax + 1] = Integer.MAX_VALUE;
+ else
+ --bmax;
+ for (d = bmax; d >= bmin; d -= 2)
+ {
+ int x, y, oldx, tlo = bd[bdiagoff + d - 1], thi = bd[bdiagoff + d + 1];
+
+ if (tlo < thi)
+ x = tlo;
+ else
+ x = thi - 1;
+ oldx = x;
+ y = x - d;
+ while (x > xoff && y > yoff && xv[x - 1] == yv[y - 1]) {
+ --x; --y;
+ }
+ if (oldx - x > SNAKE_LIMIT)
+ big_snake = true;
+ bd[bdiagoff + d] = x;
+ if (!odd && fmin <= d && d <= fmax && bd[bdiagoff + d] <= fd[fdiagoff + d])
+ {
+ cost = 2 * c;
+ return d;
+ }
+ }
+
+ /* Heuristic: check occasionally for a diagonal that has made
+ lots of progress compared with the edit distance.
+ If we have any such, find the one that has made the most
+ progress and return it as if it had succeeded.
+
+ With this heuristic, for files with a constant small density
+ of changes, the algorithm is linear in the file size. */
+
+ if (c > 200 && big_snake && heuristic)
+ {
+ int best = 0;
+ int bestpos = -1;
+
+ for (d = fmax; d >= fmin; d -= 2)
+ {
+ int dd = d - fmid;
+ int x = fd[fdiagoff + d];
+ int y = x - d;
+ int v = (x - xoff) * 2 - dd;
+ if (v > 12 * (c + (dd < 0 ? -dd : dd)))
+ {
+ if (v > best
+ && xoff + SNAKE_LIMIT <= x && x < xlim
+ && yoff + SNAKE_LIMIT <= y && y < ylim)
+ {
+ /* We have a good enough best diagonal;
+ now insist that it end with a significant snake. */
+ int k;
+
+ for (k = 1; xvec[x - k] == yvec[y - k]; k++)
+ if (k == SNAKE_LIMIT)
+ {
+ best = v;
+ bestpos = d;
+ break;
+ }
+ }
+ }
+ }
+ if (best > 0)
+ {
+ cost = 2 * c - 1;
+ return bestpos;
+ }
+
+ best = 0;
+ for (d = bmax; d >= bmin; d -= 2)
+ {
+ int dd = d - bmid;
+ int x = bd[bdiagoff + d];
+ int y = x - d;
+ int v = (xlim - x) * 2 + dd;
+ if (v > 12 * (c + (dd < 0 ? -dd : dd)))
+ {
+ if (v > best
+ && xoff < x && x <= xlim - SNAKE_LIMIT
+ && yoff < y && y <= ylim - SNAKE_LIMIT)
+ {
+ /* We have a good enough best diagonal;
+ now insist that it end with a significant snake. */
+ int k;
+
+ for (k = 0; xvec[x + k] == yvec[y + k]; k++)
+ if (k == SNAKE_LIMIT)
+ {
+ best = v;
+ bestpos = d;
+ break;
+ }
+ }
+ }
+ }
+ if (best > 0)
+ {
+ cost = 2 * c - 1;
+ return bestpos;
+ }
+ }
+ }
+ }
+
+ /** Compare in detail contiguous subsequences of the two files
+ which are known, as a whole, to match each other.
+
+ The results are recorded in the vectors filevec[N].changed_flag, by
+ storing a 1 in the element for each line that is an insertion or deletion.
+
+ The subsequence of file 0 is [XOFF, XLIM) and likewise for file 1.
+
+ Note that XLIM, YLIM are exclusive bounds.
+ All line numbers are origin-0 and discarded lines are not counted. */
+
+ private void compareseq (int xoff, int xlim, int yoff, int ylim) {
+ /* Slide down the bottom initial diagonal. */
+ while (xoff < xlim && yoff < ylim && xvec[xoff] == yvec[yoff]) {
+ ++xoff; ++yoff;
+ }
+ /* Slide up the top initial diagonal. */
+ while (xlim > xoff && ylim > yoff && xvec[xlim - 1] == yvec[ylim - 1]) {
+ --xlim; --ylim;
+ }
+
+ /* Handle simple cases. */
+ if (xoff == xlim)
+ while (yoff < ylim)
+ filevec[1].changed_flag[1+filevec[1].realindexes[yoff++]] = true;
+ else if (yoff == ylim)
+ while (xoff < xlim)
+ filevec[0].changed_flag[1+filevec[0].realindexes[xoff++]] = true;
+ else
+ {
+ /* Find a point of correspondence in the middle of the files. */
+
+ int d = diag (xoff, xlim, yoff, ylim);
+ int c = cost;
+ int f = fdiag[fdiagoff + d];
+ int b = bdiag[bdiagoff + d];
+
+ if (c == 1)
+ {
+ /* This should be impossible, because it implies that
+ one of the two subsequences is empty,
+ and that case was handled above without calling `diag'.
+ Let's verify that this is true. */
+ throw new IllegalArgumentException("Empty subsequence");
+ }
+ else
+ {
+ /* Use that point to split this problem into two subproblems. */
+ compareseq (xoff, b, yoff, b - d);
+ /* This used to use f instead of b,
+ but that is incorrect!
+ It is not necessarily the case that diagonal d
+ has a snake from b to f. */
+ compareseq (b, xlim, b - d, ylim);
+ }
+ }
+ }
+
+ /** Discard lines from one file that have no matches in the other file.
+ */
+
+ private void discard_confusing_lines() {
+ filevec[0].discard_confusing_lines(filevec[1]);
+ filevec[1].discard_confusing_lines(filevec[0]);
+ }
+
+ private boolean inhibit = false;
+
+ /** Adjust inserts/deletes of blank lines to join changes
+ as much as possible.
+ */
+
+ private void shift_boundaries() {
+ if (inhibit)
+ return;
+ filevec[0].shift_boundaries(filevec[1]);
+ filevec[1].shift_boundaries(filevec[0]);
+ }
+
+ public interface ScriptBuilder {
+ /** Scan the tables of which lines are inserted and deleted,
+ producing an edit script.
+ @param changed0 true for lines in first file which do not match 2nd
+ @param len0 number of lines in first file
+ @param changed1 true for lines in 2nd file which do not match 1st
+ @param len1 number of lines in 2nd file
+ @return a linked list of changes - or null
+ */
+ public change build_script(
+ boolean[] changed0,int len0,
+ boolean[] changed1,int len1
+ );
+ }
+
+ /** Scan the tables of which lines are inserted and deleted,
+ producing an edit script in reverse order. */
+
+ static class ReverseScript implements ScriptBuilder {
+ public change build_script(
+ final boolean[] changed0,int len0,
+ final boolean[] changed1,int len1)
+ {
+ change script = null;
+ int i0 = 0, i1 = 0;
+ while (i0 < len0 || i1 < len1) {
+ if (changed0[1+i0] || changed1[1+i1]) {
+ int line0 = i0, line1 = i1;
+
+ /* Find # lines changed here in each file. */
+ while (changed0[1+i0]) ++i0;
+ while (changed1[1+i1]) ++i1;
+
+ /* Record this change. */
+ script = new change(line0, line1, i0 - line0, i1 - line1, script);
+ }
+
+ /* We have reached lines in the two files that match each other. */
+ i0++; i1++;
+ }
+
+ return script;
+ }
+ }
+
+ static class ForwardScript implements ScriptBuilder {
+ /** Scan the tables of which lines are inserted and deleted,
+ producing an edit script in forward order. */
+ public change build_script(
+ final boolean[] changed0,int len0,
+ final boolean[] changed1,int len1)
+ {
+ change script = null;
+ int i0 = len0, i1 = len1;
+
+ while (i0 >= 0 || i1 >= 0)
+ {
+ if (changed0[i0] || changed1[i1])
+ {
+ int line0 = i0, line1 = i1;
+
+ /* Find # lines changed here in each file. */
+ while (changed0[i0]) --i0;
+ while (changed1[i1]) --i1;
+
+ /* Record this change. */
+ script = new change(i0, i1, line0 - i0, line1 - i1, script);
+ }
+
+ /* We have reached lines in the two files that match each other. */
+ i0--; i1--;
+ }
+
+ return script;
+ }
+ }
+
+ /** Standard ScriptBuilders. */
+ public final static ScriptBuilder
+ forwardScript = new ForwardScript(),
+ reverseScript = new ReverseScript();
+
+ /* Report the differences of two files. DEPTH is the current directory
+ depth. */
+ public final change diff_2(final boolean reverse) {
+ return diff(reverse ? reverseScript : forwardScript);
+ }
+
+ /** Get the results of comparison as an edit script. The script
+ is described by a list of changes. The standard ScriptBuilder
+ implementations provide for forward and reverse edit scripts.
+ Alternate implementations could, for instance, list common elements
+ instead of differences.
+ @param bld an object to build the script from change flags
+ @return the head of a list of changes
+ */
+ public change diff(final ScriptBuilder bld) {
+
+ /* Some lines are obviously insertions or deletions
+ because they don't match anything. Detect them now,
+ and avoid even thinking about them in the main comparison algorithm. */
+
+ discard_confusing_lines ();
+
+ /* Now do the main comparison algorithm, considering just the
+ undiscarded lines. */
+
+ xvec = filevec[0].undiscarded;
+ yvec = filevec[1].undiscarded;
+
+ int diags =
+ filevec[0].nondiscarded_lines + filevec[1].nondiscarded_lines + 3;
+ fdiag = new int[diags];
+ fdiagoff = filevec[1].nondiscarded_lines + 1;
+ bdiag = new int[diags];
+ bdiagoff = filevec[1].nondiscarded_lines + 1;
+
+ compareseq (0, filevec[0].nondiscarded_lines,
+ 0, filevec[1].nondiscarded_lines);
+ fdiag = null;
+ bdiag = null;
+
+ /* Modify the results slightly to make them prettier
+ in cases where that can validly be done. */
+
+ shift_boundaries ();
+
+ /* Get the results of comparison in the form of a chain
+ of `struct change's -- an edit script. */
+ return bld.build_script(
+ filevec[0].changed_flag,
+ filevec[0].buffered_lines,
+ filevec[1].changed_flag,
+ filevec[1].buffered_lines
+ );
+
+ }
+
+ /** The result of comparison is an "edit script": a chain of change objects.
+ Each change represents one place where some lines are deleted
+ and some are inserted.
+
+ LINE0 and LINE1 are the first affected lines in the two files (origin 0).
+ DELETED is the number of lines deleted here from file 0.
+ INSERTED is the number of lines inserted here in file 1.
+
+ If DELETED is 0 then LINE0 is the number of the line before
+ which the insertion was done; vice versa for INSERTED and LINE1. */
+
+ public static class change {
+ /** Previous or next edit command. */
+ public change link;
+ /** # lines of file 1 changed here. */
+ public final int inserted;
+ /** # lines of file 0 changed here. */
+ public final int deleted;
+ /** Line number of 1st deleted line. */
+ public final int line0;
+ /** Line number of 1st inserted line. */
+ public final int line1;
+ /** Change is ignorable. */
+ public boolean ignore;
+
+ /** Cons an additional entry onto the front of an edit script OLD.
+ LINE0 and LINE1 are the first affected lines in the two files (origin 0).
+ DELETED is the number of lines deleted here from file 0.
+ INSERTED is the number of lines inserted here in file 1.
+
+ If DELETED is 0 then LINE0 is the number of the line before
+ which the insertion was done; vice versa for INSERTED and LINE1. */
+ public change(int line0, int line1, int deleted, int inserted, change old) {
+ this.line0 = line0;
+ this.line1 = line1;
+ this.inserted = inserted;
+ this.deleted = deleted;
+ this.link = old;
+ //System.err.println(line0+","+line1+","+inserted+","+deleted);
+ }
+
+ public String toString() {
+ String s = String.format("%d -%d +%d %d",line0,deleted,inserted,line1);
+ return (link != null) ? s = s + '\n' + link : s;
+ }
+ }
+
+ /** Data on one input file being compared.
+ */
+
+ class file_data {
+
+ /** Allocate changed array for the results of comparison. */
+ void clear() {
+ /* Allocate a flag for each line of each file, saying whether that line
+ is an insertion or deletion.
+ Allocate an extra element, always zero, at each end of each vector.
+ */
+ changed_flag = new boolean[buffered_lines + 2];
+ }
+
+ /** Return equiv_count[I] as the number of lines in this file
+ that fall in equivalence class I.
+ @return the array of equivalence class counts.
+ */
+ int[] equivCount() {
+ int[] equiv_count = new int[equiv_max];
+ for (int i = 0; i < buffered_lines; ++i)
+ ++equiv_count[equivs[i]];
+ return equiv_count;
+ }
+
+ /** Discard lines that have no matches in another file.
+
+ A line which is discarded will not be considered by the actual
+ comparison algorithm; it will be as if that line were not in the file.
+ The file's `realindexes' table maps virtual line numbers
+ (which don't count the discarded lines) into real line numbers;
+ this is how the actual comparison algorithm produces results
+ that are comprehensible when the discarded lines are counted.
+<p>
+ When we discard a line, we also mark it as a deletion or insertion
+ so that it will be printed in the output.
+ @param f the other file
+ */
+ void discard_confusing_lines(file_data f) {
+ clear();
+ /* Set up table of which lines are going to be discarded. */
+ final byte[] discarded = discardable(f.equivCount());
+
+ /* Don't really discard the provisional lines except when they occur
+ in a run of discardables, with nonprovisionals at the beginning
+ and end. */
+ filterDiscards(discarded);
+
+ /* Actually discard the lines. */
+ discard(discarded);
+ }
+
+ /** Mark to be discarded each line that matches no line of another file.
+ If a line matches many lines, mark it as provisionally discardable.
+ @see equivCount()
+ @param counts The count of each equivalence number for the other file.
+ @return 0=nondiscardable, 1=discardable or 2=provisionally discardable
+ for each line
+ */
+
+ private byte[] discardable(final int[] counts) {
+ final int end = buffered_lines;
+ final byte[] discards = new byte[end];
+ final int[] equivs = this.equivs;
+ int many = 5;
+ int tem = end / 64;
+
+ /* Multiply MANY by approximate square root of number of lines.
+ That is the threshold for provisionally discardable lines. */
+ while ((tem = tem >> 2) > 0)
+ many *= 2;
+
+ for (int i = 0; i < end; i++)
+ {
+ int nmatch;
+ if (equivs[i] == 0)
+ continue;
+ nmatch = counts[equivs[i]];
+ if (nmatch == 0)
+ discards[i] = 1;
+ else if (nmatch > many)
+ discards[i] = 2;
+ }
+ return discards;
+ }
+
+ /** Don't really discard the provisional lines except when they occur
+ in a run of discardables, with nonprovisionals at the beginning
+ and end. */
+
+ private void filterDiscards(final byte[] discards) {
+ final int end = buffered_lines;
+
+ for (int i = 0; i < end; i++)
+ {
+ /* Cancel provisional discards not in middle of run of discards. */
+ if (discards[i] == 2)
+ discards[i] = 0;
+ else if (discards[i] != 0)
+ {
+ /* We have found a nonprovisional discard. */
+ int j;
+ int length;
+ int provisional = 0;
+
+ /* Find end of this run of discardable lines.
+ Count how many are provisionally discardable. */
+ for (j = i; j < end; j++)
+ {
+ if (discards[j] == 0)
+ break;
+ if (discards[j] == 2)
+ ++provisional;
+ }
+
+ /* Cancel provisional discards at end, and shrink the run. */
+ while (j > i && discards[j - 1] == 2) {
+ discards[--j] = 0; --provisional;
+ }
+
+ /* Now we have the length of a run of discardable lines
+ whose first and last are not provisional. */
+ length = j - i;
+
+ /* If 1/4 of the lines in the run are provisional,
+ cancel discarding of all provisional lines in the run. */
+ if (provisional * 4 > length)
+ {
+ while (j > i)
+ if (discards[--j] == 2)
+ discards[j] = 0;
+ }
+ else
+ {
+ int consec;
+ int minimum = 1;
+ int tem = length / 4;
+
+ /* MINIMUM is approximate square root of LENGTH/4.
+ A subrun of two or more provisionals can stand
+ when LENGTH is at least 16.
+ A subrun of 4 or more can stand when LENGTH >= 64. */
+ while ((tem = tem >> 2) > 0)
+ minimum *= 2;
+ minimum++;
+
+ /* Cancel any subrun of MINIMUM or more provisionals
+ within the larger run. */
+ for (j = 0, consec = 0; j < length; j++)
+ if (discards[i + j] != 2)
+ consec = 0;
+ else if (minimum == ++consec)
+ /* Back up to start of subrun, to cancel it all. */
+ j -= consec;
+ else if (minimum < consec)
+ discards[i + j] = 0;
+
+ /* Scan from beginning of run
+ until we find 3 or more nonprovisionals in a row
+ or until the first nonprovisional at least 8 lines in.
+ Until that point, cancel any provisionals. */
+ for (j = 0, consec = 0; j < length; j++)
+ {
+ if (j >= 8 && discards[i + j] == 1)
+ break;
+ if (discards[i + j] == 2) {
+ consec = 0; discards[i + j] = 0;
+ }
+ else if (discards[i + j] == 0)
+ consec = 0;
+ else
+ consec++;
+ if (consec == 3)
+ break;
+ }
+
+ /* I advances to the last line of the run. */
+ i += length - 1;
+
+ /* Same thing, from end. */
+ for (j = 0, consec = 0; j < length; j++)
+ {
+ if (j >= 8 && discards[i - j] == 1)
+ break;
+ if (discards[i - j] == 2) {
+ consec = 0; discards[i - j] = 0;
+ }
+ else if (discards[i - j] == 0)
+ consec = 0;
+ else
+ consec++;
+ if (consec == 3)
+ break;
+ }
+ }
+ }
+ }
+ }
+
+ /** Actually discard the lines.
+ @param discards flags lines to be discarded
+ */
+ private void discard(final byte[] discards) {
+ final int end = buffered_lines;
+ int j = 0;
+ for (int i = 0; i < end; ++i)
+ if (no_discards || discards[i] == 0)
+ {
+ undiscarded[j] = equivs[i];
+ realindexes[j++] = i;
+ }
+ else
+ changed_flag[1+i] = true;
+ nondiscarded_lines = j;
+ }
+
+ file_data(int[] data) {
+ buffered_lines = data.length;
+ equivs = data;
+ undiscarded = new int[buffered_lines];
+ realindexes = new int[buffered_lines];
+ }
+
+ file_data(Object[] data,Map<Object,Integer> h) {
+ this(new int[data.length]);
+ // FIXME: diff 2.7 removes common prefix and common suffix
+ for (int i = 0; i < data.length; ++i) {
+ Integer ir = h.get(data[i]);
+ if (ir == null)
+ h.put(data[i],equivs[i] = equiv_max++);
+ else
+ equivs[i] = ir.intValue();
+ }
+ }
+
+ /** Adjust inserts/deletes of blank lines to join changes
+ as much as possible.
+
+ We do something when a run of changed lines include a blank
+ line at one end and have an excluded blank line at the other.
+ We are free to choose which blank line is included.
+ `compareseq' always chooses the one at the beginning,
+ but usually it is cleaner to consider the following blank line
+ to be the "change". The only exception is if the preceding blank line
+ would join this change to other changes.
+ @param f the file being compared against
+ */
+
+ void shift_boundaries(file_data f) {
+ final boolean[] changed = changed_flag;
+ final boolean[] other_changed = f.changed_flag;
+ int i = 0;
+ int j = 0;
+ int i_end = buffered_lines;
+ int preceding = -1;
+ int other_preceding = -1;
+
+ for (;;)
+ {
+ int start, end, other_start;
+
+ /* Scan forwards to find beginning of another run of changes.
+ Also keep track of the corresponding point in the other file. */
+
+ while (i < i_end && !changed[1+i])
+ {
+ while (other_changed[1+j++])
+ /* Non-corresponding lines in the other file
+ will count as the preceding batch of changes. */
+ other_preceding = j;
+ i++;
+ }
+
+ if (i == i_end)
+ break;
+
+ start = i;
+ other_start = j;
+
+ for (;;)
+ {
+ /* Now find the end of this run of changes. */
+
+ while (i < i_end && changed[1+i]) i++;
+ end = i;
+
+ /* If the first changed line matches the following unchanged one,
+ and this run does not follow right after a previous run,
+ and there are no lines deleted from the other file here,
+ then classify the first changed line as unchanged
+ and the following line as changed in its place. */
+
+ /* You might ask, how could this run follow right after another?
+ Only because the previous run was shifted here. */
+
+ if (end != i_end
+ && equivs[start] == equivs[end]
+ && !other_changed[1+j]
+ && end != i_end
+ && !((preceding >= 0 && start == preceding)
+ || (other_preceding >= 0
+ && other_start == other_preceding)))
+ {
+ changed[1+end++] = true;
+ changed[1+start++] = false;
+ ++i;
+ /* Since one line-that-matches is now before this run
+ instead of after, we must advance in the other file
+ to keep in synch. */
+ ++j;
+ }
+ else
+ break;
+ }
+
+ preceding = i;
+ other_preceding = j;
+ }
+ }
+
+ /** Number of elements (lines) in this file. */
+ final int buffered_lines;
+
+ /** Number of common prefix elements. */
+ final int prefix_lines = 0;
+
+ /** Vector, indexed by line number, containing an equivalence code for
+ each line. It is this vector that is actually compared with that
+ of another file to generate differences. */
+ private final int[] equivs;
+
+ /** Vector, like the previous one except that
+ the elements for discarded lines have been squeezed out. */
+ final int[] undiscarded;
+
+ /** Vector mapping virtual line numbers (not counting discarded lines)
+ to real ones (counting those lines). Both are origin-0. */
+ final int[] realindexes;
+
+ /** Total number of nondiscarded lines. */
+ int nondiscarded_lines;
+
+ /** Array, indexed by real origin-1 line number,
+ containing true for a line that is an insertion or a deletion.
+ The results of comparison are stored here. */
+ boolean[] changed_flag;
+
+ }
+}
diff --git a/gnudiff-1.7.pom b/gnudiff-1.7.pom
new file mode 100644
index 0000000..34946d7
--- /dev/null
+++ b/gnudiff-1.7.pom
@@ -0,0 +1,44 @@
+<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+ xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/maven-v4_0_0.xsd">
+ <modelVersion>4.0.0</modelVersion>
+
+ <groupId>com.bmsi</groupId>
+ <artifactId>gnudiff</artifactId>
+ <version>1.7</version>
+ <packaging>jar</packaging>
+ <name>GNU Diff for Java</name>
+ <description>
+ A translation of the GNU Diff algorithm to a Java class. The Diff class computes the differences
+ between two Object arrays as a list of changes. This is very general purpose. Any of the options
+ to GNU diff can be efficiently implemented as variations on how Object.equals() is implemented
+ and how the change list is printed.
+ </description>
+ <inceptionYear>2000</inceptionYear>
+ <url>http://www.bmsi.com/java/#diff</url>
+ <licenses>
+ <license>
+ <name>GNU GENERAL PUBLIC LICENSE</name>
+ <url></url>
+ <distribution>repo</distribution>
+ </license>
+ </licenses>
+ <scm>
+ <url>http://www.bmsi.com/java/#diff</url>
+ <connection>http://www.bmsi.com/java/#diff</connection>
+ </scm>
+ <developers>
+ <developer>
+ <name>Stuart Gathman</name>
+ <url>http://gathman.org/vitae/</url>
+ </developer>
+ </developers>
+ <dependencies>
+ <dependency>
+ <groupId>junit</groupId>
+ <artifactId>junit</artifactId>
+ <version>3.8.2</version>
+ </dependency>
+ </dependencies>
+</project>
+
+
diff --git a/gnudiff.spec b/gnudiff.spec
new file mode 100644
index 0000000..ba8c18e
--- /dev/null
+++ b/gnudiff.spec
@@ -0,0 +1,78 @@
+Name: gnudiff
+Version: 1.15
+Release: 6%{?dist}
+Summary: GNU Diff for Java
+
+License: GPL+
+URL: http://bmsi.com/java/#diff
+Source0: http://bmsi.com/java/Diff.java
+Source1: http://central.maven.org/maven2/com/bmsi/%{name}/1.7/%{name}-1.7.pom
+BuildArch: noarch
+
+BuildRequires: javapackages-local
+BuildRequires: junit
+
+%description
+The GNU diff algorithm translated to a Java class. The Diff class computes
+the differences between two Object arrays as a list of changes. This is
+very general purpose. Any of the options to GNU diff can be efficiently
+implemented as variations on how Object.equals() is implemented and how the
+change list is printed. DiffPrint now sports a setOutput() method. The
+DiffPrint.Base class and derivatives should really be renamed out of the
+empty package.
+
+%package javadoc
+Summary: Javadocs for %{name}
+%description javadoc
+This package contains the API documentation for %{name}.
+
+
+%prep
+%setup -qTc -n %{name}
+
+cp %{SOURCE1} %{name}.pom
+# upstream uses an old version:
+%pom_xpath_replace "/*/*[4]" "<version>%{version}</version>" %{name}.pom
+# junit must not be a runtime requirement:
+%pom_xpath_inject "/*/*[13]/*[1]" "<scope>test</scope>" %{name}.pom
+
+%build
+javac %{SOURCE0} -d .
+jar cvf %{name}.jar bmsi/
+
+javadoc %{SOURCE0} -d javadoc
+
+# Tell XMvn which artifact belongs to which POM
+%mvn_artifact %{name}.pom %{name}.jar
+
+
+%install
+%mvn_install -J javadoc/
+
+
+%files -f .mfiles
+%dir %{_javadir}/%{name}/
+%dir %{_datadir}/maven-poms/%{name}/
+
+%files javadoc -f .mfiles-javadoc
+
+
+%changelog
+* Mon Aug 18 2014 Ismael Olea <ismael at olea.org> - 1.15-6
+- Fixing https://bugzilla.redhat.com/show_bug.cgi?id=1127879#c10
+
+* Mon Aug 18 2014 Ismael Olea <ismael at olea.org> - 1.15-5
+- suggestions at https://bugzilla.redhat.com/show_bug.cgi?id=1127879#c5
+
+* Mon Aug 18 2014 Ismael Olea <ismael at olea.org> - 1.15-4
+- suggestions at https://bugzilla.redhat.com/show_bug.cgi?id=1127879#c3
+
+* Fri Aug 15 2014 Ismael Olea <ismael at olea.org> - 1.15-3
+- mavenized
+
+* Fri Aug 8 2014 Ismael Olea <ismael at olea.org> - 1.15-2
+- renamed from java-diff to gnudiff (according to mvnrepository.com)
+
+* Thu Aug 7 2014 Ismael Olea <ismael at olea.org> - 1.15-1
+- first release
+
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