CRC32C.cpp

/*
 * PROGRAM: Common Library
 * MODULE: CRC32C.cpp
 * DESCRIPTION: Hardware-accelerated hash calculation
 *
 * The contents of this file are subject to the Initial
 * Developer's Public License Version 1.0 (the "License");
 * you may not use this file except in compliance with the
 * License. You may obtain a copy of the License at
 * http://www.ibphoenix.com/main.nfs?a=ibphoenix&page=ibp_idpl.
 *
 * Software distributed under the License is distributed AS IS,
 * WITHOUT WARRANTY OF ANY KIND, either express or implied.
 * See the License for the specific language governing rights
 * and limitations under the License.
 *
 * The Original Code was created by Dmitry Sibiryakov
 * for the Firebird Open Source RDBMS project.
 *
 * Copyright (c) 2015 Dmitry Sibiryakov
 * and all contributors signed below.
 *
 * All Rights Reserved.
 * Contributor(s): ______________________________________.
 *
*/

#include"firebird.h"

// Can be used only on x86 architectures
// WARNING: With GCC must be compiled separately with -msse4.2 flag
#if defined(_M_IX86) || defined(_M_X64) || defined(__x86_64__) || defined(__i386__)

#include<nmmintrin.h>

unsignedintCRC32C(unsignedint length, constunsignedchar* value)
{
unsignedint hash_value = 0;

if (length == 1)
return_mm_crc32_u8(hash_value, *value);

if (length == 2)
return_mm_crc32_u16(hash_value, *(unsignedshort*) value);

while (length >= 4)
 {
 hash_value = _mm_crc32_u32(hash_value, *(unsignedint*) value);
 value += 4;
 length -= 4;
 }

if (length >= 2)
 {
 hash_value = _mm_crc32_u16(hash_value, *(unsignedshort*) value);
 value += 2;
 length -= 2;
 }

if (length)
 {
 hash_value = _mm_crc32_u8(hash_value, *value);
 }

return hash_value;
}

#endif// architecture check