test.c

// Copyright 2018 (c), Neven Sajko. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be found in the
// LICENSE file.

// Prints all possible single byte XOR codings of a string, sorted by proximity of the
// english letter frequency stats.

#include <ctype.h>  // isalnum
#include <stdio.h>  // fputc
#include <stdlib.h> // qsort

#include "alphabet/alphabet.h"
#include "buffer/buffer.h"
#include "encoding/encoding.h"
#include "sizeofMacros.h"
#include "xor/xor.h"

typedef struct {
	unsigned char key;
	buffer *b;
	double distance;
} sortingMember;

static sortingMember arr[0xff];

static int
qsortCompar(const void *m1, const void *m2) {
	if (((sortingMember *)m1)->distance < ((sortingMember *)m2)->distance) {
		return -1;
	}
	return 1;
}

static void
bruteAndSort(buffer *buf) {
	int k;
	for (k = 0; k < ARRAY_SIZE(arr); k++) {
		unsigned char key = k;
		double freqs[alphabetSize];

		arr[key].key = key;
		arr[key].b = xorAlloc(buf, key);

		monographFreqCount(arr[key].b, freqs);
		arr[key].distance = monographFreqScore(freqs, sumOfSquares);
	}
	QSORT(arr, ARRAY_SIZE(arr), qsortCompar);
}

static void
freeArr(void) {
	int k;
	for (k = 0; k < ARRAY_SIZE(arr); k++) {
		bufferFree(arr[k].b);
	}
}

static void
pr(buffer *o) {
	size_t i;
	for (i = 0; i < o->l; i++) {
		fputc(o->b[i], stdout);
	}
}

static void
printArr(void) {
	int i;
	for (i = 0; i < ARRAY_SIZE(arr); i++) {
		if (arr[i].distance < 0.046875) {
			fprintf(stdout, "%20g %2x ", arr[i].distance, arr[i].key);
			pr(arr[i].b);
			fputc('\n', stdout);
		}
	}
	fputc('\n', stdout);
}

static unsigned char stringBuf[1 << 10];

static void
f(void) {
	for (;;) {
		buffer si;
		int i = 0;
		int chr;
		for (;;) {
			chr = fgetc(stdin);
			if (chr == EOF || !isalnum(chr)) {
				break;
			}
			stringBuf[i] = chr;
			i++;
		}
		for (; chr != EOF;) {
			chr = fgetc(stdin);
			if (isalnum(chr)) {
				ungetc(chr, stdin);
				break;
			}
		}
		si.b = stringBuf;
		si.l = i;
		buffer *bufI = hexDecodeAlloc(&si);
		if (bufI == NULL) {
			fprintf(stderr, "error\n");
			return;
		}

		bruteAndSort(bufI);

		pr(&si);
		fputc('\n', stdout);

		printArr();

		bufferFree(bufI);
		freeArr();

		if (chr == EOF) {
			break;
		}
	}
}

int
main(void) {
	f();
	return 0;
}