ladybird/Libraries/LibGfx/Streamer.h
Lenny Maiorani 58c52b155a LibGfx: Extraction of Streamer from P*MLoader
Problem:
- `Streamer` is the same in [PBM,PGM,PPM]Loader class implementations.

Solution:
- Extract it to its own header file to reduce maintenance burden.
- Implement `read` in terms of `read_bytes` to make the class "DRY".
- Decorate all functions with `constexpr`.
2020-12-21 09:58:27 +01:00

78 lines
2.5 KiB
C++

/*
* Copyright (c) 2020, Hüseyin ASLITÜRK <asliturk@hotmail.com>, the SerenityOS developers
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
*
* 1. Redistributions of source code must retain the above copyright notice, this
* list of conditions and the following disclaimer.
*
* 2. Redistributions in binary form must reproduce the above copyright notice,
* this list of conditions and the following disclaimer in the documentation
* and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
* DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
* SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
* CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#pragma once
#include <AK/Array.h>
#include <AK/Endian.h>
#include <AK/Types.h>
#include <string.h>
namespace Gfx {
class Streamer {
public:
constexpr Streamer(const u8* data, size_t size)
: m_data_ptr(data)
, m_size_remaining(size)
{
}
template<typename T>
constexpr bool read(T& value)
{
AK::Array<u8, sizeof(T)> network_buffer {};
auto network_value = new (network_buffer.data()) AK::NetworkOrdered<T> {};
auto res = read_bytes(network_buffer.data(), sizeof(T));
value = T(*network_value);
return res;
}
constexpr bool read_bytes(u8* buffer, size_t count)
{
if (m_size_remaining < count) {
return false;
}
memcpy(buffer, m_data_ptr, count);
m_data_ptr += count;
m_size_remaining -= count;
return true;
}
constexpr bool at_end() const { return !m_size_remaining; }
constexpr void step_back()
{
m_data_ptr -= 1;
m_size_remaining += 1;
}
private:
const u8* m_data_ptr { nullptr };
size_t m_size_remaining { 0 };
};
}