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/*
* Copyright (c) 2020, the SerenityOS developers
*
* SPDX-License-Identifier: BSD-2-Clause
*/
#pragma once
#include <AK/Span.h>
#include <AK/Types.h>
#include <LibCrypto/Checksum/ChecksumFunction.h>
namespace Crypto::Checksum {
struct Table {
u32 data[256];
constexpr Table()
: data()
{
for (auto i = 0; i < 256; i++) {
u32 value = i;
for (auto j = 0; j < 8; j++) {
if (value & 1) {
value = 0xEDB88320 ^ (value >> 1);
} else {
value = value >> 1;
}
}
data[i] = value;
}
}
constexpr u32 operator[](int index) const
{
return data[index];
}
};
constexpr static auto table = Table();
class CRC32 : public ChecksumFunction<u32> {
public:
CRC32() { }
CRC32(ReadonlyBytes data)
{
update(data);
}
CRC32(u32 initial_state, ReadonlyBytes data)
: m_state(initial_state)
{
update(data);
}
void update(ReadonlyBytes data);
u32 digest();
private:
u32 m_state { ~0u };
};
}
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