Project import generated by Copybara.
PiperOrigin-RevId: 237361882
Change-Id: I109a68f44db867b20f8c6a7732b0ce657133e52a
diff --git a/quic/core/quic_data_writer.h b/quic/core/quic_data_writer.h
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+++ b/quic/core/quic_data_writer.h
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+// 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 QUICHE_QUIC_CORE_QUIC_DATA_WRITER_H_
+#define QUICHE_QUIC_CORE_QUIC_DATA_WRITER_H_
+
+#include <cstddef>
+#include <cstdint>
+
+#include "base/macros.h"
+#include "net/third_party/quiche/src/quic/core/quic_packets.h"
+#include "net/third_party/quiche/src/quic/platform/api/quic_endian.h"
+#include "net/third_party/quiche/src/quic/platform/api/quic_export.h"
+#include "net/third_party/quiche/src/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 // QUICHE_QUIC_CORE_QUIC_DATA_WRITER_H_
