282 lines
4.3 KiB
C++
282 lines
4.3 KiB
C++
|
|
|
|
#include <windows.h>
|
|
#include <stdio.h>
|
|
|
|
|
|
void
|
|
usage() {
|
|
|
|
|
|
printf( "This program evaluates hash functions \n"
|
|
"random <testfil> <depth> <number newsgroups>\n"
|
|
) ;
|
|
|
|
|
|
|
|
}
|
|
|
|
|
|
|
|
WORD
|
|
MyRand(
|
|
IN DWORD& seed,
|
|
IN DWORD val
|
|
)
|
|
{
|
|
DWORD next = seed;
|
|
next = (seed*val) * 1103515245 + 12345; // magic!!
|
|
seed = next ;
|
|
return (WORD)((next/65536) % 32768);
|
|
}
|
|
|
|
DWORD
|
|
IDHash(
|
|
IN DWORD Key1,
|
|
IN DWORD Key2
|
|
)
|
|
/*++
|
|
|
|
Routine Description:
|
|
|
|
Used to find the hash value given 2 numbers. (Used for articleid + groupId)
|
|
|
|
Arguments:
|
|
|
|
Key1 - first key to hash. MS bit mapped to LSb of hash value
|
|
Key2 - second key to hash. LS bit mapped to MS bit of hash value.
|
|
|
|
Return Value:
|
|
|
|
Hash value
|
|
|
|
--*/
|
|
{
|
|
DWORD val1 = 0, val2 = 0;
|
|
|
|
|
|
//
|
|
// Do Key1 first
|
|
//
|
|
|
|
DWORD seed1 = Key2 << (Key1 & 0xf) ;
|
|
|
|
|
|
val1 = MyRand(seed1, Key1);
|
|
|
|
DWORD seed2 = val1 << (Key2 & 0xf) ;
|
|
val2 = MyRand(seed2, Key2);
|
|
|
|
val1 |= ( MyRand(seed1, Key1+val2) << 15);
|
|
val1 |= ( MyRand(seed1, Key1+val2) << 30);
|
|
|
|
//
|
|
// ok, now do Key2
|
|
//
|
|
|
|
val2 ^= ( MyRand(seed2, Key2+val1) << 15);
|
|
val2 ^= ( MyRand(seed2, Key2+val1) << 30);
|
|
|
|
DWORD val = val1 + val2 ;
|
|
return(val);
|
|
|
|
} // IDHash
|
|
|
|
|
|
|
|
void
|
|
ComputeStatistics(
|
|
DWORD *pdw,
|
|
DWORD cdw,
|
|
DWORD& MaxHits,
|
|
DWORD& MedianHits,
|
|
DWORD& cBeyond4K,
|
|
double& AverageHits,
|
|
double Tries
|
|
) {
|
|
|
|
|
|
DWORD rgdw[4*1024] ;
|
|
|
|
ZeroMemory( rgdw, sizeof( rgdw ) ) ;
|
|
|
|
cBeyond4K = 0 ;
|
|
MaxHits = 0 ;
|
|
MedianHits = 0 ;
|
|
AverageHits = 0 ;
|
|
|
|
for( DWORD i=0; i<cdw; i++ ) {
|
|
|
|
|
|
if( pdw[i] > MaxHits )
|
|
MaxHits = pdw[i] ;
|
|
|
|
if( pdw[i] > (4*1024) ) {
|
|
|
|
cBeyond4K ++ ;
|
|
|
|
} else {
|
|
|
|
rgdw[ pdw[i] ] ++ ;
|
|
|
|
}
|
|
|
|
AverageHits += (double)pdw[i] ;
|
|
|
|
}
|
|
|
|
AverageHits /= Tries ;
|
|
|
|
DWORD TempMax = 0 ;
|
|
DWORD iMax = 0 ;
|
|
for( i=0; i < 4*1024; i++ ) {
|
|
|
|
if( rgdw[i] > TempMax ) {
|
|
TempMax = rgdw[i] ;
|
|
iMax = i ;
|
|
}
|
|
}
|
|
MedianHits = iMax ;
|
|
}
|
|
|
|
int
|
|
main( int argc, char *argv[] ) {
|
|
|
|
if( argc != 4 ) {
|
|
|
|
usage() ;
|
|
|
|
}
|
|
|
|
LPSTR lpstrFile = argv[1] ;
|
|
|
|
HANDLE hFile = CreateFile( lpstrFile,
|
|
GENERIC_READ | GENERIC_WRITE,
|
|
0,
|
|
0,
|
|
CREATE_ALWAYS,
|
|
FILE_FLAG_DELETE_ON_CLOSE,
|
|
INVALID_HANDLE_VALUE
|
|
) ;
|
|
|
|
if( hFile == INVALID_HANDLE_VALUE ) {
|
|
printf( "Can't create file %s error %d\n",
|
|
lpstrFile, GetLastError() ) ;
|
|
return 1 ;
|
|
}
|
|
|
|
if( !isdigit( *argv[2] ) ) {
|
|
|
|
usage() ;
|
|
CloseHandle( hFile ) ;
|
|
return 1 ;
|
|
}
|
|
|
|
if( !isdigit( *argv[3] ) ) {
|
|
|
|
usage() ;
|
|
CloseHandle( hFile ) ;
|
|
return 1 ;
|
|
}
|
|
|
|
DWORD depth = atoi( argv[2] ) ;
|
|
|
|
DWORD limit = atoi( argv[3] ) ;
|
|
|
|
if( depth > 29 ) {
|
|
|
|
printf( "depth too large \n" ) ;
|
|
usage() ;
|
|
return 1 ;
|
|
}
|
|
|
|
DWORD MapSize = (0x1 << depth) * sizeof( DWORD ) ;
|
|
|
|
HANDLE hMap = CreateFileMapping(
|
|
hFile,
|
|
0,
|
|
PAGE_READWRITE,
|
|
0,
|
|
MapSize,
|
|
0
|
|
) ;
|
|
|
|
if( hMap == 0 ) {
|
|
|
|
printf( "Unable to create mapping - error %d", GetLastError() ) ;
|
|
usage() ;
|
|
CloseHandle( hFile ) ;
|
|
return 1 ;
|
|
|
|
}
|
|
|
|
DWORD *pdwMap = (DWORD*)MapViewOfFile(
|
|
hMap,
|
|
FILE_MAP_ALL_ACCESS,
|
|
0,
|
|
0,
|
|
0
|
|
) ;
|
|
|
|
|
|
if( pdwMap == 0 ) {
|
|
|
|
printf( "Unable to MapViewOfFile %d\n", pdwMap ) ;
|
|
usage() ;
|
|
CloseHandle( hMap ) ;
|
|
CloseHandle( hFile ) ;
|
|
return 1 ;
|
|
|
|
}
|
|
|
|
DWORD ShiftAmount = 32 - depth ;
|
|
|
|
for( DWORD i=0; i < limit; i ++ ) {
|
|
|
|
for( DWORD j=0; j < 64 * 1024; j++ ) {
|
|
|
|
DWORD value = IDHash( i, j ) ;
|
|
|
|
value >>= ShiftAmount ;
|
|
|
|
pdwMap[value] ++ ;
|
|
}
|
|
if( i%16 == 0 ) {
|
|
printf( "advancing to group ids %d\n", i ) ;
|
|
}
|
|
}
|
|
|
|
|
|
//
|
|
// Compute Statistics
|
|
//
|
|
|
|
DWORD MaxHits = 0 ;
|
|
DWORD MedianHits = 0 ;
|
|
DWORD Beyond4K = 0 ;
|
|
|
|
double AverageHits = 0 ;
|
|
double Tries = limit * 64 * 1024 ;
|
|
|
|
ComputeStatistics( pdwMap,
|
|
(0x1 << depth),
|
|
MaxHits,
|
|
MedianHits,
|
|
Beyond4K,
|
|
AverageHits,
|
|
Tries
|
|
) ;
|
|
|
|
printf( "Report : \n"
|
|
"\tAverage Hits - %f \n"
|
|
"\tMax Hits - %d\n"
|
|
"\tMedian Hits - %d\n"
|
|
"\tNumber with more that 4096 hits - %d\n",
|
|
AverageHits,
|
|
MaxHits,
|
|
MedianHits,
|
|
Beyond4K ) ;
|
|
|
|
return 0 ;
|
|
}
|