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wumpzwumpz
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separated diff utils from unified diff utils
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+320
-292
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4 files changed

+320
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‎src/main/java/difflib/DiffUtils.java‎

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@@ -22,32 +22,23 @@
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import difflib.algorithm.DiffAlgorithm;
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import difflib.algorithm.DiffException;
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import difflib.algorithm.myers.MyersDiff;
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import difflib.patch.ChangeDelta;
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import difflib.patch.Chunk;
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import difflib.patch.Delta;
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import difflib.patch.Equalizer;
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import difflib.patch.Patch;
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import difflib.patch.PatchFailedException;
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import java.util.ArrayList;
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import java.util.Collections;
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import java.util.LinkedList;
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import java.util.List;
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import java.util.regex.Matcher;
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import java.util.regex.Pattern;
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import static java.util.stream.Collectors.joining;
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/**
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* Implements the difference and patching engine
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*
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* @author <a href="dm.naumenko@gmail.com">Dmitry Naumenko</a>
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* @version 0.4.1
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* @param T The type of the compared elements in the 'lines'.
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*/
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public final class DiffUtils {
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private static final Pattern UNIFIED_DIFF_CHUNK_REGEXP = Pattern
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.compile("^@@\\s+-(?:(\\d+)(?:,(\\d+))?)\\s+\\+(?:(\\d+)(?:,(\\d+))?)\\s+@@$");
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/**
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* Computes the difference between the original and revised list of elements with default diff
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* algorithm
@@ -163,281 +154,6 @@ public static <T> List<T> unpatch(List<T> revised, Patch<T> patch) {
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return patch.restore(revised);
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}
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/**
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* Parse the given text in unified format and creates the list of deltas for it.
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*
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* @param diff the text in unified format
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* @return the patch with deltas.
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*/
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public static Patch<String> parseUnifiedDiff(List<String> diff) {
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boolean inPrelude = true;
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List<String[]> rawChunk = new ArrayList<>();
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Patch<String> patch = new Patch<>();
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int old_ln = 0, new_ln = 0;
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String tag;
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String rest;
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for (String line : diff) {
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// Skip leading lines until after we've seen one starting with '+++'
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if (inPrelude) {
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if (line.startsWith("+++")) {
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inPrelude = false;
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}
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continue;
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}
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Matcher m = UNIFIED_DIFF_CHUNK_REGEXP.matcher(line);
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if (m.find()) {
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// Process the lines in the previous chunk
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if (!rawChunk.isEmpty()) {
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List<String> oldChunkLines = new ArrayList<>();
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List<String> newChunkLines = new ArrayList<>();
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for (String[] raw_line : rawChunk) {
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tag = raw_line[0];
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rest = raw_line[1];
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if (tag.equals(" ") || tag.equals("-")) {
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oldChunkLines.add(rest);
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}
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if (tag.equals(" ") || tag.equals("+")) {
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newChunkLines.add(rest);
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}
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}
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patch.addDelta(new ChangeDelta<>(new Chunk<>(
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old_ln - 1, oldChunkLines), new Chunk<>(
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new_ln - 1, newChunkLines)));
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rawChunk.clear();
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}
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// Parse the @@ header
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old_ln = m.group(1) == null ? 1 : Integer.parseInt(m.group(1));
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new_ln = m.group(3) == null ? 1 : Integer.parseInt(m.group(3));
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if (old_ln == 0) {
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old_ln += 1;
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}
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if (new_ln == 0) {
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new_ln += 1;
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}
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} else {
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if (line.length() > 0) {
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tag = line.substring(0, 1);
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rest = line.substring(1);
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if (tag.equals(" ") || tag.equals("+") || tag.equals("-")) {
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rawChunk.add(new String[]{tag, rest});
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}
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} else {
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rawChunk.add(new String[]{" ", ""});
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}
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}
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}
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// Process the lines in the last chunk
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if (!rawChunk.isEmpty()) {
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List<String> oldChunkLines = new ArrayList<>();
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List<String> newChunkLines = new ArrayList<>();
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for (String[] raw_line : rawChunk) {
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tag = raw_line[0];
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rest = raw_line[1];
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if (tag.equals(" ") || tag.equals("-")) {
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oldChunkLines.add(rest);
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}
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if (tag.equals(" ") || tag.equals("+")) {
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newChunkLines.add(rest);
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}
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}
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patch.addDelta(new ChangeDelta<>(new Chunk<>(
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old_ln - 1, oldChunkLines), new Chunk<>(new_ln - 1,
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newChunkLines)));
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rawChunk.clear();
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}
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return patch;
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}
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/**
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* generateUnifiedDiff takes a Patch and some other arguments, returning the Unified Diff format
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* text representing the Patch.
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*
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* @param original - Filename of the original (unrevised file)
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* @param revised - Filename of the revised file
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* @param originalLines - Lines of the original file
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* @param patch - Patch created by the diff() function
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* @param contextSize - number of lines of context output around each difference in the file.
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* @return List of strings representing the Unified Diff representation of the Patch argument.
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* @author Bill James (tankerbay@gmail.com)
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*/
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public static List<String> generateUnifiedDiff(String original,
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String revised, List<String> originalLines, Patch<String> patch,
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int contextSize) {
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if (!patch.getDeltas().isEmpty()) {
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List<String> ret = new ArrayList<>();
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ret.add("--- " + original);
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ret.add("+++ " + revised);
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List<Delta<String>> patchDeltas = new ArrayList<>(
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patch.getDeltas());
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// code outside the if block also works for single-delta issues.
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List<Delta<String>> deltas = new ArrayList<>(); // current
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// list
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// of
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// Delta's to
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// process
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Delta<String> delta = patchDeltas.get(0);
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deltas.add(delta); // add the first Delta to the current set
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// if there's more than 1 Delta, we may need to output them together
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if (patchDeltas.size() > 1) {
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for (int i = 1; i < patchDeltas.size(); i++) {
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int position = delta.getOriginal().getPosition(); // store
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// the
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// current
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// position
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// of
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// the first Delta
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// Check if the next Delta is too close to the current
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// position.
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// And if it is, add it to the current set
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Delta<String> nextDelta = patchDeltas.get(i);
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if ((position + delta.getOriginal().size() + contextSize) >= (nextDelta
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.getOriginal().getPosition() - contextSize)) {
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deltas.add(nextDelta);
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} else {
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// if it isn't, output the current set,
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// then create a new set and add the current Delta to
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// it.
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List<String> curBlock = processDeltas(originalLines,
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deltas, contextSize);
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ret.addAll(curBlock);
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deltas.clear();
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deltas.add(nextDelta);
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}
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delta = nextDelta;
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}
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319-
}
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// don't forget to process the last set of Deltas
321-
List<String> curBlock = processDeltas(originalLines, deltas,
322-
contextSize);
323-
ret.addAll(curBlock);
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return ret;
325-
}
326-
return new ArrayList<>();
327-
}
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329-
/**
330-
* processDeltas takes a list of Deltas and outputs them together in a single block of
331-
* Unified-Diff-format text.
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*
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* @param origLines - the lines of the original file
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* @param deltas - the Deltas to be output as a single block
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* @param contextSize - the number of lines of context to place around block
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* @return
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* @author Bill James (tankerbay@gmail.com)
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*/
339-
private static List<String> processDeltas(List<String> origLines,
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List<Delta<String>> deltas, int contextSize) {
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List<String> buffer = new ArrayList<>();
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int origTotal = 0; // counter for total lines output from Original
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int revTotal = 0; // counter for total lines output from Original
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int line;
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Delta<String> curDelta = deltas.get(0);
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// NOTE: +1 to overcome the 0-offset Position
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int origStart = curDelta.getOriginal().getPosition() + 1 - contextSize;
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if (origStart < 1) {
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origStart = 1;
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}
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int revStart = curDelta.getRevised().getPosition() + 1 - contextSize;
355-
if (revStart < 1) {
356-
revStart = 1;
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}
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// find the start of the wrapper context code
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int contextStart = curDelta.getOriginal().getPosition() - contextSize;
361-
if (contextStart < 0) {
362-
contextStart = 0; // clamp to the start of the file
363-
}
364-
365-
// output the context before the first Delta
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for (line = contextStart; line < curDelta.getOriginal().getPosition(); line++) { //
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buffer.add(" " + origLines.get(line));
368-
origTotal++;
369-
revTotal++;
370-
}
371-
372-
// output the first Delta
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buffer.addAll(getDeltaText(curDelta));
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origTotal += curDelta.getOriginal().getLines().size();
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revTotal += curDelta.getRevised().getLines().size();
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377-
int deltaIndex = 1;
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while (deltaIndex < deltas.size()) { // for each of the other Deltas
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Delta<String> nextDelta = deltas.get(deltaIndex);
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int intermediateStart = curDelta.getOriginal().getPosition()
381-
+ curDelta.getOriginal().getLines().size();
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for (line = intermediateStart; line < nextDelta.getOriginal()
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.getPosition(); line++) {
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// output the code between the last Delta and this one
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buffer.add(" " + origLines.get(line));
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origTotal++;
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revTotal++;
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}
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buffer.addAll(getDeltaText(nextDelta)); // output the Delta
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origTotal += nextDelta.getOriginal().getLines().size();
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revTotal += nextDelta.getRevised().getLines().size();
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curDelta = nextDelta;
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deltaIndex++;
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}
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// Now output the post-Delta context code, clamping the end of the file
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contextStart = curDelta.getOriginal().getPosition()
398-
+ curDelta.getOriginal().getLines().size();
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for (line = contextStart; (line < (contextStart + contextSize))
400-
&& (line < origLines.size()); line++) {
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buffer.add(" " + origLines.get(line));
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origTotal++;
403-
revTotal++;
404-
}
405-
406-
// Create and insert the block header, conforming to the Unified Diff
407-
// standard
408-
StringBuffer header = new StringBuffer();
409-
header.append("@@ -");
410-
header.append(origStart);
411-
header.append(",");
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header.append(origTotal);
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header.append(" +");
414-
header.append(revStart);
415-
header.append(",");
416-
header.append(revTotal);
417-
header.append(" @@");
418-
buffer.add(0, header.toString());
419-
420-
return buffer;
421-
}
422-
423-
/**
424-
* getDeltaText returns the lines to be added to the Unified Diff text from the Delta parameter
425-
*
426-
* @param delta - the Delta to output
427-
* @return list of String lines of code.
428-
* @author Bill James (tankerbay@gmail.com)
429-
*/
430-
private static List<String> getDeltaText(Delta<String> delta) {
431-
List<String> buffer = new ArrayList<>();
432-
for (String line : delta.getOriginal().getLines()) {
433-
buffer.add("-" + line);
434-
}
435-
for (String line : delta.getRevised().getLines()) {
436-
buffer.add("+" + line);
437-
}
438-
return buffer;
439-
}
440-
441157
private DiffUtils() {
442158
}
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}

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