44 lines
1.5 KiB
C
44 lines
1.5 KiB
C
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/****************************************************************
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*
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* Copyright 2005, 2009 Fidelity Information Services, Inc *
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* *
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* This source code contains the intellectual property *
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* of its copyright holder(s), and is made available *
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* under a license. If you do not know the terms of *
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* the license, please stop and do not read further. *
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* *
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****************************************************************/
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#include "mdef.h"
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#include "gdsroot.h"
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#include "gdsbt.h"
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#include "gdsfhead.h"
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#include "jnl_get_checksum.h"
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/*
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* Input :
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* buff : Pointer to the input buffer whose checksum needs to be computed.
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* bufflen : Buffer size in bytes
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*
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* Returns:
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* Computed checksum.
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*
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* Algorithm:
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* It is different from the function "jnl_get_checksum" in the sense this calculates checksum of entire length passed.
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* If bufflen is not divisible by 4, it is ROUNDED DOWN to the nearest 4-byte (uint4) multiple.
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*/
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uint4 jnl_get_checksum_entire(uint4 *buff, int bufflen)
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{
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uint4 *blk_top, blen, checksum;
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checksum = INIT_CHECKSUM_SEED;
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for (blen = bufflen / SIZEOF(*buff), blk_top = buff + blen ; buff < blk_top; buff++)
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checksum = ADJUST_CHECKSUM(checksum, *buff);
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assert(checksum);
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/* It is theoretically possible that the computed checksum turns out to be 0. In order to differentiate this
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* with the fact that the checksum was never computed, we returns INIT_CHECKSUM_SEED in the former case.
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*/
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if (!checksum)
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checksum = INIT_CHECKSUM_SEED;
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return checksum;
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}
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