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//* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
#include "ChunkSet.h"
#include "nsReadableUtils.h"
namespace mozilla {
namespace safebrowsing {
const size_t ChunkSet::IO_BUFFER_SIZE;
nsresult ChunkSet::Serialize(nsACString& aChunkStr) {
// Truncate and append rather than assigning because that's more efficient if
// aString is an nsAutoCString.
aChunkStr.Truncate();
StringJoinAppend(aChunkStr, ","_ns, mRanges,
[](nsACString& dst, const Range& range) {
dst.AppendInt((int32_t)range.Begin());
if (range.Begin() != range.End()) {
dst.Append('-');
dst.AppendInt((int32_t)range.End());
}
});
return NS_OK;
}
nsresult ChunkSet::Set(uint32_t aChunk) {
if (!Has(aChunk)) {
Range chunkRange(aChunk, aChunk);
if (mRanges.Length() == 0) {
if (!mRanges.AppendElement(chunkRange, fallible)) {
return NS_ERROR_OUT_OF_MEMORY;
}
return NS_OK;
}
if (mRanges.LastElement().Precedes(chunkRange)) {
mRanges.LastElement().End(aChunk);
} else if (chunkRange.Precedes(mRanges[0])) {
mRanges[0].Begin(aChunk);
} else {
ChunkSet tmp;
if (!tmp.mRanges.AppendElement(chunkRange, fallible)) {
return NS_ERROR_OUT_OF_MEMORY;
}
return Merge(tmp);
}
}
return NS_OK;
}
bool ChunkSet::Has(uint32_t aChunk) const {
size_t idx;
return BinarySearchIf(mRanges, 0, mRanges.Length(),
Range::IntersectionComparator(Range(aChunk, aChunk)),
&idx);
// IntersectionComparator works because we create a
// single-chunk range.
}
nsresult ChunkSet::Merge(const ChunkSet& aOther) {
size_t oldLen = mRanges.Length();
for (const Range& mergeRange : aOther.mRanges) {
if (!HasSubrange(mergeRange)) {
if (!mRanges.InsertElementSorted(mergeRange, fallible)) {
return NS_ERROR_OUT_OF_MEMORY;
}
}
}
if (oldLen < mRanges.Length()) {
for (size_t i = 1; i < mRanges.Length(); i++) {
while (mRanges[i - 1].FoldLeft(mRanges[i])) {
mRanges.RemoveElementAt(i);
if (i == mRanges.Length()) {
return NS_OK;
}
}
}
}
return NS_OK;
}
uint32_t ChunkSet::Length() const {
uint32_t len = 0;
for (const Range& range : mRanges) {
len += range.Length();
}
return len;
}
nsresult ChunkSet::Remove(const ChunkSet& aOther) {
for (const Range& removalRange : aOther.mRanges) {
if (mRanges.Length() == 0) {
return NS_OK;
}
if (mRanges.LastElement().End() < removalRange.Begin() ||
aOther.mRanges.LastElement().End() < mRanges[0].Begin()) {
return NS_OK;
}
size_t intersectionIdx;
while (BinarySearchIf(mRanges, 0, mRanges.Length(),
Range::IntersectionComparator(removalRange),
&intersectionIdx)) {
ChunkSet remains;
nsresult rv = mRanges[intersectionIdx].Remove(removalRange, remains);
if (NS_FAILED(rv)) {
return rv;
}
mRanges.RemoveElementAt(intersectionIdx);
if (!mRanges.InsertElementsAt(intersectionIdx, remains.mRanges,
fallible)) {
return NS_ERROR_OUT_OF_MEMORY;
}
}
}
return NS_OK;
}
void ChunkSet::Clear() { mRanges.Clear(); }
nsresult ChunkSet::Write(nsIOutputStream* aOut) const {
nsTArray<uint32_t> chunks(IO_BUFFER_SIZE);
for (const Range& range : mRanges) {
for (uint32_t chunk = range.Begin(); chunk <= range.End(); chunk++) {
chunks.AppendElement(chunk);
if (chunks.Length() == chunks.Capacity()) {
nsresult rv = WriteTArray(aOut, chunks);
if (NS_FAILED(rv)) {
return rv;
}
chunks.Clear();
}
}
}
nsresult rv = WriteTArray(aOut, chunks);
if (NS_FAILED(rv)) {
return rv;
}
return NS_OK;
}
nsresult ChunkSet::Read(nsIInputStream* aIn, uint32_t aNumElements) {
nsTArray<uint32_t> chunks(IO_BUFFER_SIZE);
while (aNumElements != 0) {
chunks.Clear();
uint32_t numToRead =
aNumElements > IO_BUFFER_SIZE ? IO_BUFFER_SIZE : aNumElements;
nsresult rv = ReadTArray(aIn, &chunks, numToRead);
if (NS_FAILED(rv)) {
return rv;
}
aNumElements -= numToRead;
for (uint32_t c : chunks) {
rv = Set(c);
if (NS_FAILED(rv)) {
return rv;
}
}
}
return NS_OK;
}
bool ChunkSet::HasSubrange(const Range& aSubrange) const {
for (const Range& range : mRanges) {
if (range.Contains(aSubrange)) {
return true;
} else if (!(aSubrange.Begin() > range.End() ||
range.Begin() > aSubrange.End())) {
// In this case, aSubrange overlaps this range but is not a subrange.
// because the ChunkSet implementation ensures that there are no
// overlapping ranges, this means that aSubrange cannot be a subrange of
// any of the following ranges
return false;
}
}
return false;
}
uint32_t ChunkSet::Range::Length() const { return mEnd - mBegin + 1; }
nsresult ChunkSet::Range::Remove(const Range& aRange,
ChunkSet& aRemainderSet) const {
if (mBegin < aRange.mBegin && aRange.mBegin <= mEnd) {
// aRange overlaps & follows this range
Range range(mBegin, aRange.mBegin - 1);
if (!aRemainderSet.mRanges.AppendElement(range, fallible)) {
return NS_ERROR_OUT_OF_MEMORY;
}
}
if (mBegin <= aRange.mEnd && aRange.mEnd < mEnd) {
// aRange overlaps & precedes this range
Range range(aRange.mEnd + 1, mEnd);
if (!aRemainderSet.mRanges.AppendElement(range, fallible)) {
return NS_ERROR_OUT_OF_MEMORY;
}
}
return NS_OK;
}
bool ChunkSet::Range::FoldLeft(const Range& aRange) {
if (Contains(aRange)) {
return true;
} else if (Precedes(aRange) ||
(mBegin <= aRange.mBegin && aRange.mBegin <= mEnd)) {
mEnd = aRange.mEnd;
return true;
}
return false;
}
} // namespace safebrowsing
} // namespace mozilla