/* *	HT Editor *	tools.cc * *	Copyright (C) 1999-2002 Sebastian Biallas (sb@biallas.net) * *	This program is free software; you can redistribute it and/or modify *	it under the terms of the GNU General Public License version 2 as *	published by the Free Software Foundation. * *	This program 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 General Public License for more details. * *	You should have received a copy of the GNU General Public License *	along with this program; if not, write to the Free Software *	Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. */#include "tools.h"#include "data.h"#include "htdebug.h"#include <stdlib.h>#include <stdio.h>#include <string.h>#include <math.h>uint32 delinearize(uint32 d){	return d*0x8088405+1;	/* there's magic in here... */}uint64 delinearize64(uint64 d){	return (uint64(delinearize(d))<<32)| delinearize(d>>32); /* there's less magic in here... */}int compare_keys_uint_delinear(Object *key_a, Object *key_b){	uint a = delinearize(((UInt*)key_a)->value);	uint b = delinearize(((UInt*)key_b)->value);	if (a>b) return 1; else if (a<b) return -1;	return 0;}int *random_permutation(int max){	if (!max) return NULL;	int *table= ht_malloc(max * sizeof(int));	int i,j,k,l,m;	for (i=0; i<max; i++) table[i] = i;	for (i=0; i<max; i++) {		k=rand()%(max);		l=rand()%(max);		m=rand()%(max);		j=table[k];		table[k]=table[l];		table[l]=j;		j=table[i];		table[i]=table[m];		table[m]=j;	}	return table;}/* *	entropy shit */#define LN2 0.693147180559945309417232121458177double calc_entropy(byte *buf, int size){	int p[256];	if (!size) return 0.0;	memset(p, 0, sizeof p);	for (int i=0; i<size; i++) {		p[*buf]++;		buf++;	}	double result = 0.0;	for (int i=0; i<256; i++) {		if (p[i]) {			double pi = p[i];			pi /= size;			result += pi * log(pi) / LN2;		}	}	return -result;}/* *	buffer size must be 64 bytes *	return value will be in range from 0 to 100 */int calc_entropy2(byte *buf, int size){	int p[256];	int result = 0;	if (size<3) return 0;	memset(p, 0, sizeof p);	// pass1	byte *b = buf;	for (int i=0; i < size; i++) {		if (p[*b]++ == 0) {			result ++;		}		b++;	}	memset(p, 0, sizeof p);	b = buf;	// pass2	size--;	for (int i=0; i < size; i++) {		int d = b[0]-b[1];		if (d<0) d = -d;		if (p[d]++ == 0) {			result ++;		}		b++;	}	memset(p, 0, sizeof p);	b = buf;	// pass3	size--;	for (int i=0; i < size; i++) {		int d = b[0]-b[1];		int e = b[1]-b[2];		if (d<0) d = -d;		if (e<0) e = -e;		d = d-e;		if (d<0) d = -d;		if (p[d]++ == 0) {			result ++;		}		b++;	}	return (result-3)*100/(size*3+3);}/* * "out of memory" - handlers */int out_of_memory(int size){	printf("Out of memory.");	exit(1);	return OUT_OF_MEMORY_FAIL;}int (*out_of_memory_func)(int size)=&out_of_memory;void *smalloc(size_t size){	void *p;retry:	if ((p=malloc(size))) return p;	switch (out_of_memory_func(size)) {		case OUT_OF_MEMORY_IGNORE:			return NULL;		case OUT_OF_MEMORY_RETRY:			goto retry;		default:			exit(666);	}}void *smalloc0(size_t size){	void *p;retry0:	if ((p=malloc(size))) return memset(p, 0, size);	switch (out_of_memory_func(size)) {		case OUT_OF_MEMORY_IGNORE:			return NULL;		case OUT_OF_MEMORY_RETRY:			goto retry0;		default:			exit(666);	}}