amxmodx/third_party/hashing/hashers/crc32.h

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// //////////////////////////////////////////////////////////
// crc32.h
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// Copyright (c) 2014,2015 Stephan Brumme. All rights reserved.
// see http://create.stephan-brumme.com/disclaimer.html
//
#pragma once
#include "../hashing.h"
/// compute CRC32 hash, based on Intel's Slicing-by-8 algorithm
/** Usage:
CRC32 crc32;
std::string myHash = crc32("Hello World"); // std::string
std::string myHash2 = crc32("How are you", 11); // arbitrary data, 11 bytes
// or in a streaming fashion:
CRC32 crc32;
while (more data available)
crc32.add(pointer to fresh data, number of new bytes);
std::string myHash3 = crc32.getHash();
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Note:
You can find code for the faster Slicing-by-16 algorithm on my website, too:
http://create.stephan-brumme.com/crc32/
Its unrolled version is about twice as fast but its look-up table doubled in size as well.
*/
class CRC32 //: public Hash
{
public:
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/// hash is 4 bytes long
enum { HashBytes = 4 };
/// same as reset()
CRC32();
/// compute CRC32 of a memory block
const char* operator()(const void* data, size_t numBytes);
/// compute CRC32 of a string, excluding final zero
const char* operator()(const char* text, size_t size);
/// add arbitrary number of bytes
void add(const void* data, size_t numBytes);
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/// return latest hash as 8 hex characters
const char* getHash();
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/// return latest hash as bytes
void getHash(unsigned char buffer[HashBytes]);
/// restart
void reset();
private:
/// hash
uint32_t m_hash;
};