text: // 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.
  //
  // Some helpers for quic.
  
  #ifndef NET_QUIC_CORE_QUIC_UTILS_H_
  #define NET_QUIC_CORE_QUIC_UTILS_H_
  
  #include <stddef.h>
  #include <stdint.h>
  
  #include <string>
  
  #include "base/macros.h"
  #include "base/strings/string_piece.h"
  #include "net/base/int128.h"
  #include "net/base/net_export.h"
  #include "net/quic/core/quic_protocol.h"
  
  #ifdef _MSC_VER
  // MSVC 2013 and prior don't have alignof or aligned(); they have __alignof and
  // a __declspec instead.
  #define QUIC_ALIGN_OF __alignof
  #define QUIC_ALIGNED(X) __declspec(align(X))
  #else
  #define QUIC_ALIGN_OF alignof
  #define QUIC_ALIGNED(X) __attribute__((aligned(X)))
  #endif  // _MSC_VER
  
  namespace net {
  
  class NET_EXPORT_PRIVATE QuicUtils {
   public:
    enum Priority {
      LOCAL_PRIORITY,
      PEER_PRIORITY,
    };
  
    // Returns the 64 bit FNV1a hash of the data.  See
    // http://www.isthe.com/chongo/tech/comp/fnv/index.html#FNV-param
    static uint64_t FNV1a_64_Hash(const char* data, int len);
  
    // returns the 128 bit FNV1a hash of the data.  See
    // http://www.isthe.com/chongo/tech/comp/fnv/index.html#FNV-param
    static uint128 FNV1a_128_Hash(const char* data1, int len1);
  
    // returns the 128 bit FNV1a hash of the two sequences of data.  See
    // http://www.isthe.com/chongo/tech/comp/fnv/index.html#FNV-param
    static uint128 FNV1a_128_Hash_Two(const char* data1,
                                      int len1,
                                      const char* data2,
                                      int len2);
  
    // FindMutualTag sets |out_result| to the first tag in the priority list that
    // is also in the other list and returns true. If there is no intersection it
    // returns false.
    //
    // Which list has priority is determined by |priority|.
    //
    // If |out_index| is non-nullptr and a match is found then the index of that
    // match in |their_tags| is written to |out_index|.
    static bool FindMutualTag(const QuicTagVector& our_tags,
                              const QuicTag* their_tags,
                              size_t num_their_tags,
                              Priority priority,
                              QuicTag* out_result,
                              size_t* out_index);
  
    // SerializeUint128 writes the first 96 bits of |v| in little-endian form
    // to |out|.
    static void SerializeUint128Short(uint128 v, uint8_t* out);
  
    // Returns the name of the QuicRstStreamErrorCode as a char*
    static const char* StreamErrorToString(QuicRstStreamErrorCode error);
  
    // Returns the name of the QuicErrorCode as a char*
    static const char* ErrorToString(QuicErrorCode error);
  
    // Returns the level of encryption as a char*
    static const char* EncryptionLevelToString(EncryptionLevel level);
  
    // Returns TransmissionType as a char*
    static const char* TransmissionTypeToString(TransmissionType type);
  
    // TagToString is a utility function for pretty-printing handshake messages
    // that converts a tag to a string. It will try to maintain the human friendly
    // name if possible (i.e. kABCD -> "ABCD"), or will just treat it as a number
    // if not.
    static std::string TagToString(QuicTag tag);
  
    // Returns the list of QUIC tags represented by the comma separated
    // string in |connection_options|.
    static QuicTagVector ParseQuicConnectionOptions(
        const std::string& connection_options);
  
    // Returns PeerAddressChangeType as a std::string.
    static std::string PeerAddressChangeTypeToString(PeerAddressChangeType type);
  
    static char* AsChars(unsigned char* data) {
      return reinterpret_cast<char*>(data);
    }
  
    // Deletes all the sub-frames contained in |frames|.
    static void DeleteFrames(QuicFrames* frames);
  
    // Deletes all the QuicStreamFrames for the specified |stream_id|.
    static void RemoveFramesForStream(QuicFrames* frames, QuicStreamId stream_id);
  
    // Deletes and clears all the frames and the packet from serialized packet.
    static void ClearSerializedPacket(SerializedPacket* serialized_packet);
  
    // Returns a packed representation of |path_id| and |packet_number| in which
    // the highest byte is set to |path_id| and the lower 7 bytes are the lower
    // 7 bytes of |packet_number|.
    static uint64_t PackPathIdAndPacketNumber(QuicPathId path_id,
                                              QuicPacketNumber packet_number);
  
    // Allocates a new char[] of size |packet.encrypted_length| and copies in
    // |packet.encrypted_buffer|.
    static char* CopyBuffer(const SerializedPacket& packet);
  
    // Determines and returns change type of address change from |old_address| to
    // |new_address|.
    static PeerAddressChangeType DetermineAddressChangeType(
        const IPEndPoint& old_address,
        const IPEndPoint& new_address);
  
    // This converts 'num' bytes of binary to a 2*'num'-character hexadecimal
    // representation. Return value: 2*'num' characters of ascii std::string.
    static std::string HexEncode(const char* data, size_t length);
    static std::string HexEncode(base::StringPiece data);
  
    // This converts 2*'num' hexadecimal characters to 'num' binary data.
    // Return value: 'num' bytes of binary data (via the 'to' argument).
    static std::string HexDecode(const char* data, size_t length);
    static std::string HexDecode(base::StringPiece data);
  
    // Returns a std::string containing hex and ASCII representations of |binary|,
    // side-by-side in the style of hexdump. Non-printable characters will be
    // printed as '.' in the ASCII output.
    // "0x0000:  4865 6c6c 6f2c 2051 5549 4321 0102 0304  Hello,.QUIC!...."
    static std::string HexDump(base::StringPiece binary_data);
  
   private:
    DISALLOW_COPY_AND_ASSIGN(QuicUtils);
  };
  
  // Utility function that returns an QuicIOVector object wrapped around |str|.
  // |str|'s data is stored in |iov|.
  inline QuicIOVector MakeIOVector(base::StringPiece str, struct iovec* iov) {
    iov->iov_base = const_cast<char*>(str.data());
    iov->iov_len = static_cast<size_t>(str.size());
    QuicIOVector quic_iov(iov, 1, str.size());
    return quic_iov;
  }
  
  }  // namespace net
  
  #endif  // NET_QUIC_CORE_QUIC_UTILS_H_
  