| // Copyright 2018 The Fuchsia 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 SRC_CONNECTIVITY_WLAN_LIB_COMMON_CPP_INCLUDE_WLAN_COMMON_BUFFER_WRITER_H_ |
| #define SRC_CONNECTIVITY_WLAN_LIB_COMMON_CPP_INCLUDE_WLAN_COMMON_BUFFER_WRITER_H_ |
| |
| #include <lib/stdcompat/span.h> |
| #include <zircon/assert.h> |
| #include <zircon/types.h> |
| |
| #include <cstring> |
| |
| namespace wlan { |
| |
| class BufferWriter { |
| public: |
| explicit BufferWriter(cpp20::span<uint8_t> buf) : buf_(buf) { ZX_ASSERT(buf.data() != nullptr); } |
| |
| void WriteByte(uint8_t byte) { |
| ZX_ASSERT(buf_.size() >= offset_ + 1); |
| buf_[offset_] = byte; |
| offset_ += 1; |
| } |
| |
| template <typename T> |
| void WriteValue(const T& value) { |
| Write(as_bytes(cpp20::span<const T>(&value, 1))); |
| } |
| |
| template <typename T> |
| T* Write() { |
| ZX_ASSERT(buf_.size() >= offset_ + sizeof(T)); |
| |
| memset(buf_.data() + offset_, 0, sizeof(T)); |
| auto data = reinterpret_cast<T*>(buf_.data() + offset_); |
| offset_ += sizeof(T); |
| return data; |
| } |
| |
| void Write(cpp20::span<const uint8_t> buf) { Write(as_bytes(buf)); } |
| |
| void Write(cpp20::span<const std::byte> buf) { |
| if (buf.empty()) { |
| return; |
| } |
| |
| ZX_ASSERT(buf_.size() >= offset_ + buf.size()); |
| std::memcpy(buf_.data() + offset_, buf.data(), buf.size()); |
| offset_ += buf.size(); |
| } |
| |
| cpp20::span<const uint8_t> WrittenData() const { return buf_.subspan(0, offset_); } |
| size_t WrittenBytes() const { return offset_; } |
| size_t RemainingBytes() const { return buf_.size() - offset_; } |
| cpp20::span<uint8_t> RemainingBuffer() { return buf_.subspan(offset_); } |
| |
| private: |
| size_t offset_ = 0; |
| cpp20::span<uint8_t> buf_; |
| }; |
| |
| } // namespace wlan |
| |
| #endif // SRC_CONNECTIVITY_WLAN_LIB_COMMON_CPP_INCLUDE_WLAN_COMMON_BUFFER_WRITER_H_ |