Implement c++ native lib for streaming proto, part 1

Extract protobuf class out and creates EncodedBuffer class
which holds protobuf data.
Next step is to create a ProtoOutputStream and let incident helper
adapt the change as well.
please see frameworks/base/core/java/android/util/proto

Bug: 65641021
Test: unit tested
Change-Id: I0dd343b2e62d60f091c8f857fae3452ec8da6b96

2 files changed, 295 insertions, 0 deletions

diff --git a/libs/protoutil/src/EncodedBuffer.cpp b/libs/protoutil/src/EncodedBuffer.cpp
new file mode 100644
index 000000000000..84dc5b6d7852
--- /dev/null
+++ b/libs/protoutil/src/EncodedBuffer.cpp
@@ -0,0 +1,237 @@
+/*
+ * Copyright (C) 2017 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include <android/util/EncodedBuffer.h>
+
+#include <stdlib.h>
+
+namespace android {
+namespace util {
+
+const size_t BUFFER_SIZE = 8 * 1024; // 8 KB
+
+EncodedBuffer::Pointer::Pointer() : Pointer(BUFFER_SIZE)
+{
+}
+
+EncodedBuffer::Pointer::Pointer(size_t chunkSize)
+        :mIndex(0),
+         mOffset(0)
+{
+    mChunkSize = chunkSize == 0 ? BUFFER_SIZE : chunkSize;
+}
+
+size_t
+EncodedBuffer::Pointer::pos() const
+{
+    return mIndex * mChunkSize + mOffset;
+}
+
+size_t
+EncodedBuffer::Pointer::index() const
+{
+    return mIndex;
+}
+
+size_t
+EncodedBuffer::Pointer::offset() const
+{
+    return mOffset;
+}
+
+void
+EncodedBuffer::Pointer::move(size_t amt)
+{
+    size_t newOffset = mOffset + amt;
+    mIndex += newOffset / mChunkSize;
+    mOffset = newOffset % mChunkSize;
+}
+
+void
+EncodedBuffer::Pointer::rewind()
+{
+    mIndex = 0;
+    mOffset = 0;
+}
+
+EncodedBuffer::Pointer
+EncodedBuffer::Pointer::copy() const
+{
+    Pointer p = Pointer(mChunkSize);
+    p.mIndex = mIndex;
+    p.mOffset = mOffset;
+    return p;
+}
+
+// ===========================================================
+EncodedBuffer::EncodedBuffer() : EncodedBuffer(0)
+{
+}
+
+EncodedBuffer::EncodedBuffer(size_t chunkSize)
+        :mBuffers()
+{
+    mChunkSize = chunkSize == 0 ? BUFFER_SIZE : chunkSize;
+    mWp = Pointer(mChunkSize);
+}
+
+EncodedBuffer::~EncodedBuffer()
+{
+    for (size_t i=0; i<mBuffers.size(); i++) {
+        uint8_t* buf = mBuffers[i];
+        free(buf);
+    }
+}
+
+inline uint8_t*
+EncodedBuffer::at(const Pointer& p) const
+{
+    return mBuffers[p.index()] + p.offset();
+}
+
+/******************************** Write APIs ************************************************/
+size_t
+EncodedBuffer::size() const
+{
+    return mWp.pos();
+}
+
+EncodedBuffer::Pointer*
+EncodedBuffer::wp()
+{
+    return &mWp;
+}
+
+uint8_t*
+EncodedBuffer::writeBuffer()
+{
+    // This prevents write pointer move too fast than allocating the buffer.
+    if (mWp.index() > mBuffers.size()) return NULL;
+    uint8_t* buf = NULL;
+    if (mWp.index() == mBuffers.size()) {
+        buf = (uint8_t*)malloc(mChunkSize);
+
+        if (buf == NULL) return NULL; // This indicates NO_MEMORY
+
+        mBuffers.push_back(buf);
+    }
+    return at(mWp);
+}
+
+size_t
+EncodedBuffer::currentToWrite()
+{
+    return mChunkSize - mWp.offset();
+}
+
+size_t
+EncodedBuffer::writeRawVarint(uint32_t val)
+{
+    size_t size = 0;
+    while (true) {
+        size++;
+        if ((val & ~0x7F) == 0) {
+            *writeBuffer() = (uint8_t) val;
+            mWp.move();
+            return size;
+        } else {
+            *writeBuffer() = (uint8_t)((val & 0x7F) | 0x80);
+            mWp.move();
+            val >>= 7;
+        }
+    }
+}
+
+size_t
+EncodedBuffer::writeHeader(uint32_t fieldId, uint8_t wireType)
+{
+    return writeRawVarint((fieldId << 3) | wireType);
+}
+
+/********************************* Read APIs ************************************************/
+EncodedBuffer::iterator
+EncodedBuffer::begin() const
+{
+    return EncodedBuffer::iterator(*this);
+}
+
+EncodedBuffer::iterator::iterator(const EncodedBuffer& buffer)
+        :mData(buffer),
+         mRp(buffer.mChunkSize)
+{
+}
+
+size_t
+EncodedBuffer::iterator::size() const
+{
+    return mData.size();
+}
+
+size_t
+EncodedBuffer::iterator::bytesRead() const
+{
+    return mRp.pos();
+}
+
+EncodedBuffer::Pointer*
+EncodedBuffer::iterator::rp()
+{
+    return &mRp;
+}
+
+uint8_t const*
+EncodedBuffer::iterator::readBuffer()
+{
+    return hasNext() ? const_cast<uint8_t const*>(mData.at(mRp)) : NULL;
+}
+
+size_t
+EncodedBuffer::iterator::currentToRead()
+{
+    return (mData.mWp.index() > mRp.index()) ?
+            mData.mChunkSize - mRp.offset() :
+            mData.mWp.offset() - mRp.offset();
+}
+
+bool
+EncodedBuffer::iterator::hasNext()
+{
+    return mRp.pos() < mData.mWp.pos();
+}
+
+uint8_t
+EncodedBuffer::iterator::next()
+{
+    uint8_t res = *(mData.at(mRp));
+    mRp.move();
+    return res;
+}
+
+uint32_t
+EncodedBuffer::iterator::readRawVarint()
+{
+    uint32_t val = 0, shift = 0;
+    while (true) {
+        uint8_t byte = next();
+        val += (byte & 0x7F) << shift;
+        if ((byte & 0x80) == 0) break;
+        shift += 7;
+    }
+    return val;
+}
+
+} // util
+} // android
diff --git a/libs/protoutil/src/protobuf.cpp b/libs/protoutil/src/protobuf.cpp
new file mode 100644
index 000000000000..ec5325c57bd1
--- /dev/null
+++ b/libs/protoutil/src/protobuf.cpp
@@ -0,0 +1,58 @@
+/*
+ * Copyright (C) 2016 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include <android/util/protobuf.h>
+
+namespace android {
+namespace util {
+
+uint8_t
+read_wire_type(uint32_t varint)
+{
+    return (uint8_t) (varint & 0x07);
+}
+
+uint32_t
+read_field_id(uint32_t varint)
+{
+    return varint >> 3;
+}
+
+uint8_t*
+write_raw_varint(uint8_t* buf, uint32_t val)
+{
+    uint8_t* p = buf;
+    while (true) {
+        if ((val & ~0x7F) == 0) {
+            *p++ = (uint8_t)val;
+            return p;
+        } else {
+            *p++ = (uint8_t)((val & 0x7F) | 0x80);
+            val >>= 7;
+        }
+    }
+}
+
+uint8_t*
+write_length_delimited_tag_header(uint8_t* buf, uint32_t fieldId, size_t size)
+{
+    buf = write_raw_varint(buf, (fieldId << 3) | 2);
+    buf = write_raw_varint(buf, size);
+    return buf;
+}
+
+} // util
+} // android