| /* |
| * 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 <nvram/messages/io.h> |
| |
| extern "C" { |
| #include <string.h> |
| } |
| |
| #include <nvram/messages/compiler.h> |
| |
| namespace nvram { |
| namespace { |
| |
| template <typename T> |
| T min(T x, T y) { |
| return x < y ? x : y; |
| } |
| |
| template <typename T> |
| T max(T x, T y) { |
| return x > y ? x : y; |
| } |
| |
| // Encodes |value| in varint format and writes the result to |stream|. |
| bool EncodeVarint(OutputStreamBuffer* stream, uint64_t value) { |
| do { |
| uint8_t byte = (value & 0x7f) | (((value >> 7) == 0) ? 0x00 : 0x80); |
| if (!stream->WriteByte(byte)) { |
| return false; |
| } |
| value >>= 7; |
| } while (value != 0); |
| return true; |
| } |
| |
| // Read a varint-encoded number from stream, decode it and store the result in |
| // |value|. |
| bool DecodeVarint(InputStreamBuffer* stream_buffer, uint64_t* value) { |
| // Maximum number of bytes required to encode an |uint64_t| as varint. Each |
| // byte in a varint has 7 payload bytes, so encoding 64 bits yields at most 10 |
| // bytes. |
| static constexpr int kMaxVarintBytes = 10; |
| |
| *value = 0; |
| for (int i = 0; i < kMaxVarintBytes; ++i) { |
| uint8_t byte = 0; |
| if (!stream_buffer->ReadByte(&byte)) { |
| return false; |
| } |
| *value |= static_cast<uint64_t>(byte & 0x7f) << (i * 7); |
| if ((byte & 0x80) == 0) { |
| return true; |
| } |
| } |
| return false; |
| } |
| |
| } // namespace |
| |
| InputStreamBuffer::InputStreamBuffer(const void* data, size_t size) |
| : InputStreamBuffer(data, static_cast<const uint8_t*>(data) + size) {} |
| |
| InputStreamBuffer::InputStreamBuffer(const void* start, const void* end) |
| : pos_(static_cast<const uint8_t*>(start)), |
| end_(static_cast<const uint8_t*>(end)) { |
| NVRAM_CHECK(pos_ <= end_); |
| } |
| |
| bool InputStreamBuffer::Done() { |
| return pos_ >= end_ && !Advance(); |
| } |
| |
| bool InputStreamBuffer::Read(void* data, size_t size) { |
| uint8_t* buffer = static_cast<uint8_t*>(data); |
| NVRAM_CHECK(pos_ <= end_); |
| while (size > static_cast<size_t>(end_ - pos_)) { |
| memcpy(buffer, pos_, end_ - pos_); |
| buffer += end_ - pos_; |
| size -= end_ - pos_; |
| pos_ = end_; |
| if (!Advance()) { |
| return false; |
| } |
| NVRAM_CHECK(pos_ < end_); |
| } |
| memcpy(buffer, pos_, size); |
| pos_ += size; |
| return true; |
| } |
| |
| bool InputStreamBuffer::ReadByte(uint8_t* byte) { |
| if (pos_ >= end_) { |
| if (!Advance()) { |
| return false; |
| } |
| NVRAM_CHECK(pos_ < end_); |
| } |
| *byte = *pos_; |
| ++pos_; |
| return true; |
| } |
| |
| bool InputStreamBuffer::Skip(size_t size) { |
| NVRAM_CHECK(pos_ <= end_); |
| while (size > static_cast<size_t>(end_ - pos_)) { |
| size -= end_ - pos_; |
| pos_ = end_; |
| if (!Advance()) { |
| return false; |
| } |
| NVRAM_CHECK(pos_ < end_); |
| } |
| pos_ += size; |
| return true; |
| } |
| |
| bool InputStreamBuffer::Advance() { |
| return false; |
| } |
| |
| NestedInputStreamBuffer::NestedInputStreamBuffer(InputStreamBuffer* delegate, |
| size_t size) |
| : InputStreamBuffer(delegate->pos_, ClampEnd(delegate, size)), |
| delegate_(delegate), |
| remaining_(size) {} |
| |
| bool NestedInputStreamBuffer::Advance() { |
| remaining_ -= end_ - delegate_->pos_; |
| if (remaining_ == 0) { |
| delegate_->pos_ = end_; |
| return false; |
| } |
| bool status = delegate_->Advance(); |
| pos_ = delegate_->pos_; |
| end_ = ClampEnd(delegate_, remaining_); |
| return status; |
| } |
| |
| // static |
| const uint8_t* NestedInputStreamBuffer::ClampEnd(InputStreamBuffer* delegate, |
| size_t size) { |
| NVRAM_CHECK(delegate->pos_ <= delegate->end_); |
| return size < static_cast<size_t>(delegate->end_ - delegate->pos_) |
| ? delegate->pos_ + size |
| : delegate->end_; |
| } |
| |
| OutputStreamBuffer::OutputStreamBuffer(void* data, size_t size) |
| : OutputStreamBuffer(data, static_cast<uint8_t*>(data) + size) {} |
| |
| OutputStreamBuffer::OutputStreamBuffer(void* start, void* end) |
| : pos_(static_cast<uint8_t*>(start)), end_(static_cast<uint8_t*>(end)) { |
| NVRAM_CHECK(pos_ <= end_); |
| } |
| |
| bool OutputStreamBuffer::Done() { |
| return pos_ >= end_ && !Advance(); |
| } |
| |
| bool OutputStreamBuffer::Write(const void* data, size_t size) { |
| const uint8_t* buffer = static_cast<const uint8_t*>(data); |
| NVRAM_CHECK(pos_ <= end_); |
| while (size > static_cast<size_t>(end_ - pos_)) { |
| memcpy(pos_, buffer, end_ - pos_); |
| buffer += end_ - pos_; |
| size -= end_ - pos_; |
| pos_ = end_; |
| if (!Advance()) { |
| return false; |
| } |
| NVRAM_CHECK(pos_ < end_); |
| } |
| memcpy(pos_, buffer, size); |
| pos_ += size; |
| return true; |
| } |
| |
| bool OutputStreamBuffer::WriteByte(uint8_t byte) { |
| if (pos_ >= end_) { |
| if (!Advance()) { |
| return false; |
| } |
| NVRAM_CHECK(pos_ < end_); |
| } |
| *pos_ = byte; |
| ++pos_; |
| return true; |
| } |
| |
| bool OutputStreamBuffer::Advance() { |
| return false; |
| } |
| |
| CountingOutputStreamBuffer::CountingOutputStreamBuffer() |
| : OutputStreamBuffer(scratch_space_, kScratchSpaceSize) {} |
| |
| bool CountingOutputStreamBuffer::Advance() { |
| bytes_written_ += pos_ - scratch_space_; |
| pos_ = scratch_space_; |
| end_ = scratch_space_ + kScratchSpaceSize; |
| return true; |
| } |
| |
| uint8_t CountingOutputStreamBuffer::scratch_space_[kScratchSpaceSize]; |
| |
| BlobOutputStreamBuffer::BlobOutputStreamBuffer(Blob* blob) |
| : OutputStreamBuffer(blob->data(), blob->size()), blob_(blob) {} |
| |
| bool BlobOutputStreamBuffer::Advance() { |
| ptrdiff_t offset = pos_ - blob_->data(); |
| if (!blob_->Resize(max<size_t>(blob_->size() * 2, 32))) { |
| return false; |
| } |
| pos_ = blob_->data() + offset; |
| end_ = blob_->data() + blob_->size(); |
| return true; |
| } |
| |
| bool BlobOutputStreamBuffer::Truncate() { |
| if (!blob_->Resize(pos_ - blob_->data())) { |
| return false; |
| } |
| end_ = blob_->data() + blob_->size(); |
| pos_ = end_; |
| return true; |
| } |
| |
| ProtoReader::ProtoReader(InputStreamBuffer* stream_buffer) |
| : stream_buffer_(stream_buffer) {} |
| |
| bool ProtoReader::ReadWireTag() { |
| uint64_t wire_tag; |
| if (!DecodeVarint(stream_buffer_, &wire_tag)) { |
| return false; |
| } |
| |
| wire_type_ = wire_tag & 0x7; |
| field_number_ = wire_tag >> 3; |
| switch (wire_type()) { |
| case WireType::kLengthDelimited: { |
| uint64_t size; |
| if (!DecodeVarint(stream_buffer_, &size)) { |
| return false; |
| } |
| field_size_ = static_cast<size_t>(size); |
| if (static_cast<uint64_t>(field_size_) != size) { |
| return false; |
| } |
| break; |
| } |
| case WireType::kFixed64: |
| field_size_ = sizeof(uint64_t); |
| break; |
| case WireType::kFixed32: |
| field_size_ = sizeof(uint32_t); |
| break; |
| case WireType::kVarint: |
| case WireType::kStartGroup: |
| case WireType::kEndGroup: |
| field_size_ = 0; |
| break; |
| } |
| |
| return true; |
| } |
| |
| bool ProtoReader::ReadVarint(uint64_t* value) { |
| NVRAM_CHECK(wire_type() == WireType::kVarint); |
| return DecodeVarint(stream_buffer_, value); |
| } |
| |
| bool ProtoReader::ReadLengthDelimited(void* data, size_t size) { |
| NVRAM_CHECK(wire_type() == WireType::kLengthDelimited); |
| return stream_buffer_->Read(data, size); |
| } |
| |
| bool ProtoReader::SkipField() { |
| if (wire_type() == WireType::kVarint) { |
| uint64_t dummy; |
| return DecodeVarint(stream_buffer_, &dummy); |
| } else if (field_size_ > 0) { |
| return stream_buffer_->Skip(field_size_); |
| } |
| |
| return true; |
| } |
| |
| ProtoWriter::ProtoWriter(OutputStreamBuffer* stream_buffer) |
| : stream_buffer_(stream_buffer) {} |
| |
| bool ProtoWriter::WriteVarint(uint64_t value) { |
| return WriteWireTag(WireType::kVarint) && |
| EncodeVarint(stream_buffer_, value); |
| } |
| |
| bool ProtoWriter::WriteLengthDelimited(const void* data, size_t size) { |
| return WriteWireTag(WireType::kLengthDelimited) && |
| EncodeVarint(stream_buffer_, size) && |
| stream_buffer_->Write(data, size); |
| } |
| |
| bool ProtoWriter::WriteLengthHeader(size_t size) { |
| return WriteWireTag(WireType::kLengthDelimited) && |
| EncodeVarint(stream_buffer_, size); |
| } |
| |
| bool ProtoWriter::WriteWireTag(WireType wire_type) { |
| return EncodeVarint(stream_buffer_, |
| (field_number_ << 3) | static_cast<uint64_t>(wire_type)); |
| } |
| |
| } // namespace nvram |