|
|
@@ -1,848 +0,0 @@ |
|
|
|
package jdiff.util; |
|
|
|
|
|
|
|
import java.util.Hashtable; |
|
|
|
|
|
|
|
/** 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) |
|
|
|
{ |
|
|
|
Hashtable h = new Hashtable(a.length + b.length); |
|
|
|
filevec[0] = new file_data(a,h); |
|
|
|
filevec[1] = new file_data(b,h); |
|
|
|
} |
|
|
|
|
|
|
|
/** 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 = new file_data[2]; |
|
|
|
private int cost; |
|
|
|
|
|
|
|
/** 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 > 20) |
|
|
|
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 > 20) |
|
|
|
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; |
|
|
|
if ((fd[fdiagoff + d] - xoff)*2 - dd > 12 * (c + (dd > 0 ? dd : -dd))) |
|
|
|
{ |
|
|
|
if (fd[fdiagoff + d] * 2 - dd > best |
|
|
|
&& fd[fdiagoff + d] - xoff > 20 |
|
|
|
&& fd[fdiagoff + d] - d - yoff > 20) |
|
|
|
{ |
|
|
|
int k; |
|
|
|
int x = fd[fdiagoff + d]; |
|
|
|
|
|
|
|
/* We have a good enough best diagonal; |
|
|
|
now insist that it end with a significant snake. */ |
|
|
|
for (k = 1; k <= 20; k++) |
|
|
|
if (xvec[x - k] != yvec[x - d - k]) |
|
|
|
break; |
|
|
|
|
|
|
|
if (k == 21) |
|
|
|
{ |
|
|
|
best = fd[fdiagoff + d] * 2 - dd; |
|
|
|
bestpos = d; |
|
|
|
} |
|
|
|
} |
|
|
|
} |
|
|
|
} |
|
|
|
if (best > 0) |
|
|
|
{ |
|
|
|
cost = 2 * c - 1; |
|
|
|
return bestpos; |
|
|
|
} |
|
|
|
|
|
|
|
best = 0; |
|
|
|
for (d = bmax; d >= bmin; d -= 2) |
|
|
|
{ |
|
|
|
int dd = d - bmid; |
|
|
|
if ((xlim - bd[bdiagoff + d])*2 + dd > 12 * (c + (dd > 0 ? dd : -dd))) |
|
|
|
{ |
|
|
|
if ((xlim - bd[bdiagoff + d]) * 2 + dd > best |
|
|
|
&& xlim - bd[bdiagoff + d] > 20 |
|
|
|
&& ylim - (bd[bdiagoff + d] - d) > 20) |
|
|
|
{ |
|
|
|
/* We have a good enough best diagonal; |
|
|
|
now insist that it end with a significant snake. */ |
|
|
|
int k; |
|
|
|
int x = bd[bdiagoff + d]; |
|
|
|
|
|
|
|
for (k = 0; k < 20; k++) |
|
|
|
if (xvec[x + k] != yvec[x - d + k]) |
|
|
|
break; |
|
|
|
if (k == 20) |
|
|
|
{ |
|
|
|
best = (xlim - bd[bdiagoff + d]) * 2 + dd; |
|
|
|
bestpos = d; |
|
|
|
} |
|
|
|
} |
|
|
|
} |
|
|
|
} |
|
|
|
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]); |
|
|
|
} |
|
|
|
|
|
|
|
/** Scan the tables of which lines are inserted and deleted, |
|
|
|
producing an edit script in reverse order. */ |
|
|
|
|
|
|
|
private change build_reverse_script() { |
|
|
|
change script = null; |
|
|
|
final boolean[] changed0 = filevec[0].changed_flag; |
|
|
|
final boolean[] changed1 = filevec[1].changed_flag; |
|
|
|
final int len0 = filevec[0].buffered_lines; |
|
|
|
final int len1 = filevec[1].buffered_lines; |
|
|
|
|
|
|
|
/* Note that changedN[len0] does exist, and contains 0. */ |
|
|
|
|
|
|
|
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; |
|
|
|
} |
|
|
|
|
|
|
|
/** Scan the tables of which lines are inserted and deleted, |
|
|
|
producing an edit script in forward order. */ |
|
|
|
|
|
|
|
private change build_script() { |
|
|
|
change script = null; |
|
|
|
final boolean[] changed0 = filevec[0].changed_flag; |
|
|
|
final boolean[] changed1 = filevec[1].changed_flag; |
|
|
|
final int len0 = filevec[0].buffered_lines; |
|
|
|
final int len1 = filevec[1].buffered_lines; |
|
|
|
int i0 = len0, i1 = len1; |
|
|
|
|
|
|
|
/* Note that changedN[-1] does exist, and contains 0. */ |
|
|
|
|
|
|
|
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; |
|
|
|
} |
|
|
|
|
|
|
|
/* Report the differences of two files. DEPTH is the current directory |
|
|
|
depth. */ |
|
|
|
public change diff_2(final boolean reverse) { |
|
|
|
|
|
|
|
/* 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. */ |
|
|
|
|
|
|
|
if (reverse) |
|
|
|
return build_reverse_script(); |
|
|
|
else |
|
|
|
return build_script(); |
|
|
|
} |
|
|
|
|
|
|
|
/** 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; |
|
|
|
|
|
|
|
/** 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. */ |
|
|
|
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); |
|
|
|
} |
|
|
|
} |
|
|
|
|
|
|
|
/** 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(Object[] data,Hashtable h) { |
|
|
|
buffered_lines = data.length; |
|
|
|
|
|
|
|
equivs = new int[buffered_lines]; |
|
|
|
undiscarded = new int[buffered_lines]; |
|
|
|
realindexes = new int[buffered_lines]; |
|
|
|
|
|
|
|
for (int i = 0; i < data.length; ++i) { |
|
|
|
Integer ir = (Integer)h.get(data[i]); |
|
|
|
if (ir == null) |
|
|
|
h.put(data[i],new Integer(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; |
|
|
|
|
|
|
|
/** 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; |
|
|
|
|
|
|
|
} |
|
|
|
} |