74 lines
1.5 KiB
C
74 lines
1.5 KiB
C
/** @file
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Helper functions for calculating CRC32 checksum
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;******************************************************************************
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;* Copyright (c) 2012, Insyde Software Corp. All Rights Reserved.
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;*
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;* You may not reproduce, distribute, publish, display, perform, modify, adapt,
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;* transmit, broadcast, present, recite, release, license or otherwise exploit
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;* any part of this publication in any form, by any means, without the prior
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;* written permission of Insyde Software Corporation.
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;*
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;******************************************************************************
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*/
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UINT32 mCrcTable[256];
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/**
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This internal function reverses bits for 32bit data.
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@param Value The data to be reversed.
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@return Data reversed.
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**/
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UINT32
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ReverseBits (
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UINT32 Value
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)
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{
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UINTN Index;
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UINT32 NewValue;
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NewValue = 0;
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for (Index = 0; Index < 32; Index++) {
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if ((Value & (1 << Index)) != 0) {
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NewValue = NewValue | (1 << (31 - Index));
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}
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}
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return NewValue;
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}
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/**
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Initialize CRC32 table.
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@param none
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@retval none
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**/
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VOID
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InitializeCrc32Table (
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VOID
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)
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{
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UINTN TableEntry;
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UINTN Index;
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UINT32 Value;
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for (TableEntry = 0; TableEntry < 256; TableEntry++) {
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Value = ReverseBits ((UINT32) TableEntry);
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for (Index = 0; Index < 8; Index++) {
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if ((Value & 0x80000000) != 0) {
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Value = (Value << 1) ^ 0x04c11db7;
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} else {
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Value = Value << 1;
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}
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}
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mCrcTable[TableEntry] = ReverseBits (Value);
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}
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}
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