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e6f2cd0b2a
$ git grep ' $' | grep -v ^test/ | cut -d : -f 1 | sort -u > /tmp/trailing $ for a in `cat /tmp/trailing` ; do sed -i -e 's/ *$//' $a ; done
33 lines
692 B
C
33 lines
692 B
C
/*
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* This code was done
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* by an anonymous gnome
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* ------------------------
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* That's pure mathematics, so no sense to adding license shit here.
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*/
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#include <stdlib.h>
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#include <math.h>
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#include "r_types.h"
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R_API double r_hash_entropy(const ut8 *data, ut64 size) {
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if (!data || !size) {
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return 0;
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}
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ut64 i, count[256] = {0};
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double h = 0;
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for (i = 0; i < size; i++) {
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count[data[i]]++;
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}
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for (i = 0; i < 256; i++) {
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if (count[i]) {
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double p = (double) count[i] / size;
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h -= p * log2 (p);
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}
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}
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return h;
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}
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R_API double r_hash_entropy_fraction(const ut8 *data, ut64 size) {
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return size ? r_hash_entropy (data, size) / \
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log2 ((double) R_MIN (size, 256)) : 0;
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}
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