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/** @file
This file implements CalculateCrc32 Boot Services as defined in
Platform Initialization specification 1.0 VOLUME 2 DXE Core Interface.
This Boot Services is in the Runtime Driver because this service is
also required by SetVirtualAddressMap() when the EFI System Table and
EFI Runtime Services Table are converted from physical address to
virtual addresses. This requires that the 32-bit CRC be recomputed.
Copyright (c) 2006 - 2008, Intel Corporation. <BR>
All rights reserved. This program and the accompanying materials
are licensed and made available under the terms and conditions of the BSD License
which accompanies this distribution. The full text of the license may be found at
http://opensource.org/licenses/bsd-license.php
THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
**/
#include <Uefi.h>
UINT32 mCrcTable[256];
/**
Calculate CRC32 for target data.
@param Data The target data.
@param DataSize The target data size.
@param CrcOut The CRC32 for target data.
@retval EFI_SUCCESS The CRC32 for target data is calculated successfully.
@retval EFI_INVALID_PARAMETER Some parameter is not valid, so the CRC32 is not
calculated.
**/
EFI_STATUS
EFIAPI
RuntimeDriverCalculateCrc32 (
IN VOID *Data,
IN UINTN DataSize,
OUT UINT32 *CrcOut
)
{
UINT32 Crc;
UINTN Index;
UINT8 *Ptr;
if (Data == NULL || DataSize == 0 || CrcOut == NULL) {
return EFI_INVALID_PARAMETER;
}
Crc = 0xffffffff;
for (Index = 0, Ptr = Data; Index < DataSize; Index++, Ptr++) {
Crc = (Crc >> 8) ^ mCrcTable[(UINT8) Crc ^ *Ptr];
}
*CrcOut = Crc ^ 0xffffffff;
return EFI_SUCCESS;
}
/**
This internal function reverses bits for 32bit data.
@param Value The data to be reversed.
@return Data reversed.
**/
UINT32
ReverseBits (
UINT32 Value
)
{
UINTN Index;
UINT32 NewValue;
NewValue = 0;
for (Index = 0; Index < 32; Index++) {
if ((Value & (1 << Index)) != 0) {
NewValue = NewValue | (1 << (31 - Index));
}
}
return NewValue;
}
/**
Initialize CRC32 table.
**/
VOID
RuntimeDriverInitializeCrc32Table (
VOID
)
{
UINTN TableEntry;
UINTN Index;
UINT32 Value;
for (TableEntry = 0; TableEntry < 256; TableEntry++) {
Value = ReverseBits ((UINT32) TableEntry);
for (Index = 0; Index < 8; Index++) {
if ((Value & 0x80000000) != 0) {
Value = (Value << 1) ^ 0x04c11db7;
} else {
Value = Value << 1;
}
}
mCrcTable[TableEntry] = ReverseBits (Value);
}
}
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