| 1 | // Copyright (C) Microsoft Corporation. All rights reserved. |
| 2 | // SPDX-License-Identifier: MIT |
| 3 | |
| 4 | #pragma once |
| 5 | #include <vector> |
| 6 | |
| 7 | class Packet |
| 8 | { |
| 9 | public: |
| 10 | static constexpr long InitialReservedHeader = 128; |
| 11 | static constexpr long InitialPacketSize = 2048; |
| 12 | |
| 13 | // Initial state is data_offset==data_end_offset |
| 14 | void reset() |
| 15 | { |
| 16 | data_offset = InitialReservedHeader; |
| 17 | data_end_offset = data_offset + InitialPacketSize; |
| 18 | Buffer.resize(InitialReservedHeader + InitialPacketSize); |
| 19 | } |
| 20 | |
| 21 | uint8_t* data() |
| 22 | { |
| 23 | return &Buffer[data_offset]; |
| 24 | } |
| 25 | |
| 26 | uint8_t* data_end() |
| 27 | { |
| 28 | return &Buffer[data_end_offset]; |
| 29 | } |
| 30 | |
| 31 | bool adjust_head(long count) |
| 32 | { |
| 33 | if ((count + data_offset) < 0) |
| 34 | { |
| 35 | return false; |
| 36 | } |
| 37 | |
| 38 | if ((count + data_offset) > data_end_offset) |
| 39 | { |
| 40 | return false; |
| 41 | } |
| 42 | |
| 43 | data_offset += count; |
| 44 | return true; |
| 45 | } |
| 46 | |
| 47 | bool adjust_tail(long count) |
| 48 | { |
| 49 | if ((count + data_end_offset) < data_offset) |
| 50 | { |
| 51 | return false; |
| 52 | } |
| 53 | if ((count + data_end_offset) > Buffer.size()) |
| 54 | { |
| 55 | Buffer.resize(count + data_end_offset); |
| 56 | } |
| 57 | |
| 58 | data_end_offset += count; |
| 59 | return true; |
| 60 | } |
| 61 | |
| 62 | private: |
| 63 | long data_offset = 0; |
| 64 | long data_end_offset = 0; |
| 65 | std::vector<uint8_t> Buffer; |
| 66 | }; |