| // Copyright (c) 2012 The Chromium Authors. All rights reserved. |
| // Use of this source code is governed by a BSD-style license that can be |
| // found in the LICENSE file. |
| |
| #ifndef NET_THIRD_PARTY_QUIC_CORE_QUIC_DATA_WRITER_H_ |
| #define NET_THIRD_PARTY_QUIC_CORE_QUIC_DATA_WRITER_H_ |
| |
| #include <cstddef> |
| #include <cstdint> |
| |
| #include "base/macros.h" |
| #include "net/third_party/quic/core/quic_packets.h" |
| #include "net/third_party/quic/platform/api/quic_endian.h" |
| #include "net/third_party/quic/platform/api/quic_export.h" |
| #include "net/third_party/quic/platform/api/quic_string_piece.h" |
| |
| namespace quic { |
| |
| class QuicRandom; |
| |
| // Maximum value that can be properly encoded using VarInt62 coding. |
| const uint64_t kVarInt62MaxValue = UINT64_C(0x3fffffffffffffff); |
| |
| // VarInt62 encoding masks |
| // If a uint64_t anded with a mask is not 0 then the value is encoded |
| // using that length (or is too big, in the case of kVarInt62ErrorMask). |
| // Values must be checked in order (error, 8-, 4-, and then 2- bytes) |
| // and if none are non-0, the value is encoded in 1 byte. |
| const uint64_t kVarInt62ErrorMask = UINT64_C(0xc000000000000000); |
| const uint64_t kVarInt62Mask8Bytes = UINT64_C(0x3fffffffc0000000); |
| const uint64_t kVarInt62Mask4Bytes = UINT64_C(0x000000003fffc000); |
| const uint64_t kVarInt62Mask2Bytes = UINT64_C(0x0000000000003fc0); |
| |
| // This class provides facilities for packing QUIC data. |
| // |
| // The QuicDataWriter supports appending primitive values (int, string, etc) |
| // to a frame instance. The internal memory buffer is exposed as the "data" |
| // of the QuicDataWriter. |
| class QUIC_EXPORT_PRIVATE QuicDataWriter { |
| public: |
| // Creates a QuicDataWriter where |buffer| is not owned |
| // using NETWORK_BYTE_ORDER endianness. |
| QuicDataWriter(size_t size, char* buffer); |
| // Creates a QuicDataWriter where |buffer| is not owned |
| // using the specified endianness. |
| QuicDataWriter(size_t size, char* buffer, Endianness endianness); |
| QuicDataWriter(const QuicDataWriter&) = delete; |
| QuicDataWriter& operator=(const QuicDataWriter&) = delete; |
| |
| ~QuicDataWriter(); |
| |
| // Returns the size of the QuicDataWriter's data. |
| size_t length() const { return length_; } |
| |
| // Retrieves the buffer from the QuicDataWriter without changing ownership. |
| char* data(); |
| |
| // Methods for adding to the payload. These values are appended to the end |
| // of the QuicDataWriter payload. |
| |
| // Writes 8/16/32/64-bit unsigned integers. |
| bool WriteUInt8(uint8_t value); |
| bool WriteUInt16(uint16_t value); |
| bool WriteUInt32(uint32_t value); |
| bool WriteUInt64(uint64_t value); |
| |
| // Write an unsigned-integer value per the IETF QUIC/Variable Length |
| // Integer encoding rules (see draft-ietf-quic-transport-08.txt). |
| // IETF Variable Length Integers have 62 significant bits, so the |
| // value to write must be in the range of 0...(2^62)-1. Returns |
| // false if the value is out of range or if there is no room in the |
| // buffer. |
| bool WriteVarInt62(uint64_t value); |
| |
| // Same as WriteVarInt62(uint64_t), but forces an encoding size to write to. |
| // This is not as optimized as WriteVarInt62(uint64_t). |
| // Returns false if the value does not fit in the specified write_length or if |
| // there is no room in the buffer. |
| bool WriteVarInt62(uint64_t value, |
| QuicVariableLengthIntegerLength write_length); |
| |
| // Writes a string piece as a consecutive length/content pair. The |
| // length is VarInt62 encoded. |
| bool WriteStringPieceVarInt62(const QuicStringPiece& string_piece); |
| |
| // Utility function to return the number of bytes needed to encode |
| // the given value using IETF VarInt62 encoding. Returns the number |
| // of bytes required to encode the given integer or 0 if the value |
| // is too large to encode. |
| static QuicVariableLengthIntegerLength GetVarInt62Len(uint64_t value); |
| |
| // Writes least significant |num_bytes| of a 64-bit unsigned integer in the |
| // correct byte order. |
| bool WriteBytesToUInt64(size_t num_bytes, uint64_t value); |
| |
| // Write unsigned floating point corresponding to the value. Large values are |
| // clamped to the maximum representable (kUFloat16MaxValue). Values that can |
| // not be represented directly are rounded down. |
| bool WriteUFloat16(uint64_t value); |
| bool WriteStringPiece(QuicStringPiece val); |
| bool WriteStringPiece16(QuicStringPiece val); |
| bool WriteBytes(const void* data, size_t data_len); |
| bool WriteRepeatedByte(uint8_t byte, size_t count); |
| // Fills the remaining buffer with null characters. |
| void WritePadding(); |
| // Write padding of |count| bytes. |
| bool WritePaddingBytes(size_t count); |
| |
| // Write connection ID to the payload. |
| bool WriteConnectionId(QuicConnectionId connection_id); |
| |
| // Write tag as a 32-bit unsigned integer to the payload. As tags are already |
| // converted to big endian (e.g., CHLO is 'C','H','L','O') in memory by TAG or |
| // MakeQuicTag and tags are written in byte order, so tags on the wire are |
| // in big endian. |
| bool WriteTag(uint32_t tag); |
| |
| // Write |length| random bytes generated by |random|. |
| bool WriteRandomBytes(QuicRandom* random, size_t length); |
| |
| size_t capacity() const { return capacity_; } |
| |
| size_t remaining() const { return capacity_ - length_; } |
| |
| QuicString DebugString() const; |
| |
| private: |
| // Returns the location that the data should be written at, or nullptr if |
| // there is not enough room. Call EndWrite with the returned offset and the |
| // given length to pad out for the next write. |
| char* BeginWrite(size_t length); |
| |
| // TODO(fkastenholz, b/73004262) change buffer_, et al, to be uint8_t, not |
| // char. |
| char* buffer_; |
| size_t capacity_; // Allocation size of payload (or -1 if buffer is const). |
| size_t length_; // Current length of the buffer. |
| |
| // The endianness to write integers and floating numbers. |
| Endianness endianness_; |
| }; |
| |
| } // namespace quic |
| |
| #endif // NET_THIRD_PARTY_QUIC_CORE_QUIC_DATA_WRITER_H_ |