115 lines
2.0 KiB
C
115 lines
2.0 KiB
C
#include "tweak.h"
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#include <stdio.h>
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#include <stdlib.h>
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#include "my-string.h"
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#include <math.h>
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static int bitcount[16];
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static int rounds;
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static int result;
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#define MAX_WORST_ALLOWED 0.1f
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/* FSP classic algo */
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static unsigned short classic PROTO0((void))
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{
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unsigned long k;
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k = random();
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k = k ^ (k >> 8) ^ (k >> 16) ^ (k << 8);
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return k;
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}
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/* get low bits from random result */
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static unsigned short simple PROTO0((void))
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{
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return random();
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}
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/* get high bits from random result - better */
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static unsigned short simple2 PROTO0((void))
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{
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return (random() >> 15);
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}
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/* The following algorithm is recommended by Numerical Recipies: */
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/* Best, but needs floating point division */
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static unsigned short nr(void)
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{
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unsigned short ulRandom = ((float)(0xffff)*rand()/(RAND_MAX+1.0f));
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return(ulRandom);
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}
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static void run_randomtest( unsigned short (*keygen)(void) )
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{
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int i,j;
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unsigned short rnd;
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/* zero bitcount first */
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memset(bitcount,0,16*sizeof(int));
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for(i=0;i<rounds;i++)
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{
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rnd=keygen();
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for(j=0;j<16;j++)
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{
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if(rnd & 1)
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bitcount[j]++;
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rnd=rnd>>1;
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}
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}
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}
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static void print_bitcount(void)
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{
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int i;
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float worst;
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float ratio;
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printf("Set ratio: ");
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worst=0;
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for(i=0;i<16;i++)
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{
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ratio=(float)bitcount[i]/rounds;
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if(fabs(ratio-0.5f)>worst)
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worst=fabs(ratio-0.5f);
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printf("%.2f ",ratio);
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}
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printf(" Worst: %.3f\n",worst);
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if(worst>MAX_WORST_ALLOWED) result++;
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}
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int main(int argc,const char *argv[])
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{
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rounds=2000;
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if(argc>1)
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{
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rounds=atoi(argv[1]);
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}
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printf("Running %d rounds.\n\n",rounds);
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result=0;
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printf("Generator: classic\n");
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run_randomtest(classic);
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print_bitcount();
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printf("Generator: simple\n");
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run_randomtest(simple);
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print_bitcount();
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printf("Generator: simple2\n");
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run_randomtest(simple2);
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print_bitcount();
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result=0;
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printf("Generator: Numerical Recipes\n");
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run_randomtest(nr);
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print_bitcount();
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return result;
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}
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