| // Copyright (c) 2016 The WebM project authors. All Rights Reserved. |
| // |
| // Use of this source code is governed by a BSD-style license |
| // that can be found in the LICENSE file in the root of the source |
| // tree. An additional intellectual property rights grant can be found |
| // in the file PATENTS. All contributing project authors may |
| // be found in the AUTHORS file in the root of the source tree. |
| #ifndef SRC_BOOL_PARSER_H_ |
| #define SRC_BOOL_PARSER_H_ |
| |
| #include <cassert> |
| #include <cstdint> |
| |
| #include "src/element_parser.h" |
| #include "src/parser_utils.h" |
| #include "webm/callback.h" |
| #include "webm/element.h" |
| #include "webm/reader.h" |
| #include "webm/status.h" |
| |
| namespace webm { |
| |
| // Parses a boolean from a byte stream. EBML does not have a boolean type, but |
| // the Matroska spec defines some unsigned integer elements that have a range of |
| // [0, 1]. The BoolParser parses these unsigned integer elements into |
| // true/false, and reports a Status::kInvalidElementValue error if the integer |
| // is outside of its permitted range. |
| class BoolParser : public ElementParser { |
| public: |
| explicit BoolParser(bool default_value = false) |
| : default_value_(default_value) {} |
| |
| Status Init(const ElementMetadata& metadata, |
| std::uint64_t max_size) override { |
| assert(metadata.size == kUnknownElementSize || metadata.size <= max_size); |
| |
| // Booleans are really just unsigned integers with a range limit of 0-1. |
| // Unsigned integers can't be encoded with more than 8 bytes. |
| if (metadata.size > 8) { |
| return Status(Status::kInvalidElementSize); |
| } |
| |
| size_ = num_bytes_remaining_ = static_cast<int>(metadata.size); |
| value_ = default_value_; |
| |
| return Status(Status::kOkCompleted); |
| } |
| |
| Status Feed(Callback* callback, Reader* reader, |
| std::uint64_t* num_bytes_read) override { |
| assert(callback != nullptr); |
| assert(reader != nullptr); |
| assert(num_bytes_read != nullptr); |
| |
| std::uint64_t uint_value = 0; |
| const Status status = AccumulateIntegerBytes(num_bytes_remaining_, reader, |
| &uint_value, num_bytes_read); |
| num_bytes_remaining_ -= static_cast<int>(*num_bytes_read); |
| |
| // Only the last byte should have a value, and it should only be 0 or 1. |
| if ((num_bytes_remaining_ != 0 && uint_value != 0) || uint_value > 1) { |
| return Status(Status::kInvalidElementValue); |
| } |
| |
| if (size_ > 0) { |
| value_ = uint_value == 1; |
| } |
| |
| return status; |
| } |
| |
| // Gets the parsed bool. This must not be called until the parse had been |
| // successfully completed. |
| bool value() const { |
| assert(num_bytes_remaining_ == 0); |
| return value_; |
| } |
| |
| // Gets the parsed bool. This must not be called until the parse had been |
| // successfully completed. |
| bool* mutable_value() { |
| assert(num_bytes_remaining_ == 0); |
| return &value_; |
| } |
| |
| private: |
| bool value_; |
| bool default_value_; |
| int num_bytes_remaining_ = -1; |
| int size_; |
| }; |
| |
| } // namespace webm |
| |
| #endif // SRC_BOOL_PARSER_H_ |