/** @return ArrayList as we need a serializable object */
public ArrayList<Block> chunk(String resourceId, List<TokensLine> fragments) {
List<TokensLine> filtered = Lists.newArrayList();
int i = 0;
while (i < fragments.size()) {
TokensLine first = fragments.get(i);
int j = i + 1;
while (j < fragments.size() && fragments.get(j).getValue().equals(first.getValue())) {
j++;
}
filtered.add(fragments.get(i));
if (i < j - 1) {
filtered.add(fragments.get(j - 1));
}
i = j;
}
fragments = filtered;
if (fragments.size() < blockSize) {
return Lists.newArrayList();
}
TokensLine[] fragmentsArr = fragments.toArray(new TokensLine[fragments.size()]);
ArrayList<Block> blocks = Lists.newArrayListWithCapacity(fragmentsArr.length - blockSize + 1);
long hash = 0;
int first = 0;
int last = 0;
for (; last < blockSize - 1; last++) {
hash = hash * PRIME_BASE + fragmentsArr[last].getHashCode();
}
Block.Builder blockBuilder = Block.builder().setResourceId(resourceId);
for (; last < fragmentsArr.length; last++, first++) {
TokensLine firstFragment = fragmentsArr[first];
TokensLine lastFragment = fragmentsArr[last];
// add last statement to hash
hash = hash * PRIME_BASE + lastFragment.getHashCode();
// create block
Block block =
blockBuilder
.setBlockHash(new ByteArray(hash))
.setIndexInFile(first)
.setLines(firstFragment.getStartLine(), lastFragment.getEndLine())
.setUnit(firstFragment.getStartUnit(), lastFragment.getEndUnit())
.build();
blocks.add(block);
// remove first statement from hash
hash -= power * firstFragment.getHashCode();
}
return blocks;
}
/**
* Given file with two lines, containing following statements:
*
* <pre>
* 0: A,B,A,B
* 1: A,B,A
* </pre>
*
* with block size 5 each block will span both lines, and hashes will be:
*
* <pre>
* A,B,A,B,A=1
* B,A,B,A,B=2
* A,B,A,B,A=1
* </pre>
*
* Expected: one clone with two parts, which contain exactly the same lines
*/
@Test
public void same_lines_but_different_indexes() {
CloneIndex cloneIndex = createIndex();
Block.Builder block = Block.builder().setResourceId("a").setLines(0, 1);
Block[] fileBlocks =
new Block[] {
block.setBlockHash(new ByteArray("1".getBytes())).setIndexInFile(0).build(),
block.setBlockHash(new ByteArray("2".getBytes())).setIndexInFile(1).build(),
block.setBlockHash(new ByteArray("1".getBytes())).setIndexInFile(2).build()
};
List<CloneGroup> clones = detect(cloneIndex, fileBlocks);
print(clones);
assertThat(clones.size(), is(1));
Iterator<CloneGroup> clonesIterator = clones.iterator();
CloneGroup clone = clonesIterator.next();
assertThat(clone.getCloneUnitLength(), is(1));
assertThat(clone.getCloneParts().size(), is(2));
assertThat(clone.getOriginPart(), is(new ClonePart("a", 0, 0, 1)));
assertThat(clone.getCloneParts(), hasItem(new ClonePart("a", 0, 0, 1)));
assertThat(clone.getCloneParts(), hasItem(new ClonePart("a", 2, 0, 1)));
}