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/* IBM_PROLOG_BEGIN_TAG */
/* This is an automatically generated prolog. */
/* */
/* $Source: src/usr/diag/prdf/common/util/UtilHash.H $ */
/* */
/* IBM CONFIDENTIAL */
/* */
/* COPYRIGHT International Business Machines Corp. 2004,2012 */
/* */
/* p1 */
/* */
/* Object Code Only (OCO) source materials */
/* Licensed Internal Code Source Materials */
/* IBM HostBoot Licensed Internal Code */
/* */
/* The source code for this program is not published or otherwise */
/* divested of its trade secrets, irrespective of what has been */
/* deposited with the U.S. Copyright Office. */
/* */
/* Origin: 30 */
/* */
/* IBM_PROLOG_END_TAG */
#ifndef __UTIL_UTILHASH_H
#define __UTIL_UTILHASH_H
#include <stdint.h>
namespace Util
{
inline uint32_t hashString(const char * i_str)
{
// This hash is a simple "n*s[0] + (n-1)*s[1] + ... + s[n-1]" algorithm,
// where s[i] is a two byte chunk of the input string. It is currently
// intended to return a 16-bit hash of the input string.
uint32_t sumA = 0;
uint32_t sumB = 0;
uint32_t pos = 0;
uint32_t val = 0;
const uint32_t bytes = sizeof(uint16_t); // 16-bit hashing
i_str--; // This looks weird but it is because of the do-while loop. We
// want it to loop through one more time when we have reached
// the end of the string (i.e. with the '\0' character).
do
{
i_str++;
if ('\0' != *i_str)
{
val <<= 8;
val |= (uint8_t) *i_str;
pos++;
}
else
{
while (bytes != pos)
{
val <<= 8;
pos++;
}
}
if (bytes == pos)
{
pos = 0;
sumA += val;
sumB += sumA;
val = 0;
}
} while ('\0' != *i_str);
return (sumB & 0xffff); // 16-bit hashing
};
inline uint32_t hashAdler32(const char * i_str)
{
uint32_t sumA = 1;
uint32_t sumB = 0;
while ('\0' != *i_str)
{
sumA += *i_str;
sumB += sumA;
sumA %= 65521;
sumB %= 65521;
i_str++;
}
return ((sumB << 16) | sumA) & 0x7FFFFFFF;
};
};
#endif
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