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-rw-r--r--mysys/checksum.c30
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diff --git a/mysys/checksum.c b/mysys/checksum.c
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+++ b/mysys/checksum.c
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+/* Copyright (C) 2000 MySQL AB & MySQL Finland AB & TCX DataKonsult AB
+
+ This library is free software; you can redistribute it and/or
+ modify it under the terms of the GNU Library General Public
+ License as published by the Free Software Foundation; either
+ version 2 of the License, or (at your option) any later version.
+
+ This library is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ Library General Public License for more details.
+
+ You should have received a copy of the GNU Library General Public
+ License along with this library; if not, write to the Free
+ Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
+ MA 02111-1307, USA */
+
+/* Calculate a long checksum for a memoryblock. Used to verify pack_isam */
+
+#include <global.h>
+#include "my_sys.h"
+
+ulong checksum(const byte *mem, uint count)
+{
+ ulong crc;
+ for (crc=0; count-- ; mem++)
+ crc=((crc << 1) + *((uchar*) mem)) +
+ test(crc & ((ulong) 1L << (8*sizeof(ulong)-1)));
+ return crc;
+}