AAPT2: Refactor PngCrunching
PngCrunching now has a slightly better heuristic of choosing to encode
an image as a palette or RGB. For small images, RGB compresses much better
than a palette.
The original PNG is used as-is (minus some optional chunks being stripped)
if the resulting crunched PNG is larger than the original.
9-patch handling is abstracted away from PNGs, paving the way
for other 9-patches, like WebP.
TODO: handle PNGs with 9-patch chunks already present, which
should just be passed through. This will allow for 3rd party
tools to generate 9-patches.
TODO: implement cheap transparency: when one color is used to represent
transparent, and all other colors are opaque.
Bug:30053276
Change-Id: I5167f53b91d1efa462d9f03d6b9108d9b541c0c1
diff --git a/tools/aapt2/util/BigBuffer.cpp b/tools/aapt2/util/BigBuffer.cpp
index c88e3c1..de4ecd2 100644
--- a/tools/aapt2/util/BigBuffer.cpp
+++ b/tools/aapt2/util/BigBuffer.cpp
@@ -49,4 +49,29 @@
return mBlocks.back().buffer.get();
}
+void* BigBuffer::nextBlock(size_t* outSize) {
+ if (!mBlocks.empty()) {
+ Block& block = mBlocks.back();
+ if (block.size != block.mBlockSize) {
+ void* outBuffer = block.buffer.get() + block.size;
+ size_t size = block.mBlockSize - block.size;
+ block.size = block.mBlockSize;
+ mSize += size;
+ *outSize = size;
+ return outBuffer;
+ }
+ }
+
+ // Zero-allocate the block's buffer.
+ Block block = {};
+ block.buffer = std::unique_ptr<uint8_t[]>(new uint8_t[mBlockSize]());
+ assert(block.buffer);
+ block.size = mBlockSize;
+ block.mBlockSize = mBlockSize;
+ mBlocks.push_back(std::move(block));
+ mSize += mBlockSize;
+ *outSize = mBlockSize;
+ return mBlocks.back().buffer.get();
+}
+
} // namespace aapt
diff --git a/tools/aapt2/util/BigBuffer.h b/tools/aapt2/util/BigBuffer.h
index ba8532f..685614f 100644
--- a/tools/aapt2/util/BigBuffer.h
+++ b/tools/aapt2/util/BigBuffer.h
@@ -82,6 +82,20 @@
T* nextBlock(size_t count = 1);
/**
+ * Returns the next block available and puts the size in outCount.
+ * This is useful for grabbing blocks where the size doesn't matter.
+ * Use backUp() to give back any bytes that were not used.
+ */
+ void* nextBlock(size_t* outCount);
+
+ /**
+ * Backs up count bytes. This must only be called after nextBlock()
+ * and can not be larger than sizeof(T) * count of the last nextBlock()
+ * call.
+ */
+ void backUp(size_t count);
+
+ /**
* Moves the specified BigBuffer into this one. When this method
* returns, buffer is empty.
*/
@@ -97,6 +111,8 @@
*/
void align4();
+ size_t getBlockSize() const;
+
const_iterator begin() const;
const_iterator end() const;
@@ -123,6 +139,10 @@
return mSize;
}
+inline size_t BigBuffer::getBlockSize() const {
+ return mBlockSize;
+}
+
template <typename T>
inline T* BigBuffer::nextBlock(size_t count) {
static_assert(std::is_standard_layout<T>::value, "T must be standard_layout type");
@@ -130,6 +150,12 @@
return reinterpret_cast<T*>(nextBlockImpl(sizeof(T) * count));
}
+inline void BigBuffer::backUp(size_t count) {
+ Block& block = mBlocks.back();
+ block.size -= count;
+ mSize -= count;
+}
+
inline void BigBuffer::appendBuffer(BigBuffer&& buffer) {
std::move(buffer.mBlocks.begin(), buffer.mBlocks.end(), std::back_inserter(mBlocks));
mSize += buffer.mSize;
diff --git a/tools/aapt2/util/StringPiece.h b/tools/aapt2/util/StringPiece.h
index 4300a67..266c003 100644
--- a/tools/aapt2/util/StringPiece.h
+++ b/tools/aapt2/util/StringPiece.h
@@ -39,6 +39,9 @@
using const_iterator = const TChar*;
using difference_type = size_t;
+ // End of string marker.
+ constexpr static const size_t npos = static_cast<size_t>(-1);
+
BasicStringPiece();
BasicStringPiece(const BasicStringPiece<TChar>& str);
BasicStringPiece(const std::basic_string<TChar>& str); // NOLINT(implicit)
@@ -48,7 +51,7 @@
BasicStringPiece<TChar>& operator=(const BasicStringPiece<TChar>& rhs);
BasicStringPiece<TChar>& assign(const TChar* str, size_t len);
- BasicStringPiece<TChar> substr(size_t start, size_t len) const;
+ BasicStringPiece<TChar> substr(size_t start, size_t len = npos) const;
BasicStringPiece<TChar> substr(BasicStringPiece<TChar>::const_iterator begin,
BasicStringPiece<TChar>::const_iterator end) const;
@@ -81,6 +84,9 @@
//
template <typename TChar>
+constexpr const size_t BasicStringPiece<TChar>::npos;
+
+template <typename TChar>
inline BasicStringPiece<TChar>::BasicStringPiece() : mData(nullptr) , mLength(0) {
}
@@ -127,7 +133,11 @@
template <typename TChar>
inline BasicStringPiece<TChar> BasicStringPiece<TChar>::substr(size_t start, size_t len) const {
- if (start + len > mLength) {
+ if (len == npos) {
+ len = mLength - start;
+ }
+
+ if (start > mLength || start + len > mLength) {
return BasicStringPiece<TChar>();
}
return BasicStringPiece<TChar>(mData + start, len);