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/* an - Anagram generator
Copyright (C) 2012 Paul Martin <pm@debian.org>
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.
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.,
51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
*/
#include <stdlib.h>
#include <stdbool.h>
#include <unicode/uchar.h>
#include <unicode/ustring.h>
#include "bitfield.h"
#include "malloc.h"
struct bitfield *
make_bitfield(const UChar *word, const UChar *alphabet)
{
int alphabetlength = u_strlen(alphabet);
int *freqs = safe_calloc(alphabetlength, sizeof(int));
struct bitfield *bf;
int maxfreq = 0;
int index;
if (freqs == NULL)
return NULL;
while (*word) {
const UChar *p = alphabet;
for (index = 0; *p && (*p != *word); p++, index++) {
}
if (*p) {
freqs[index]++;
if (freqs[index] > maxfreq) {
maxfreq = freqs[index];
}
} else {
/* character not in alphabet */
free(freqs);
return NULL;
}
word++;
}
bf = safe_calloc(1, sizeof(struct bitfield));
if (bf != NULL) {
bitpattern thisbit;
bf->depth = maxfreq;
bf->bits = safe_calloc(sizeof(bitpattern), maxfreq);
thisbit = 1;
for (index = 0; index <alphabetlength; index++) {
bitpattern *bits = bf->bits;
while (freqs[index] > 0) {
*bits |= thisbit;
bits++;
freqs[index]--;
}
thisbit <<= 1;
}
}
free(freqs);
return bf;
}
void
free_bitfield(struct bitfield *bits)
{
if (bits != NULL)
free(bits->bits);
free(bits);
}
bool
bf_contains(struct bitfield *a, struct bitfield *b)
{
int i;
if ((a == NULL) || (b == NULL))
return false;
if (a->depth < b->depth)
return false;
for (i = 0; i < b->depth; i++) {
if ((a->bits[i] & b->bits[i]) != b->bits[i])
return false;
}
return true;
}
struct bitfield *
bf_subtract(struct bitfield *a, struct bitfield *b)
{
/* assumption is that both are in normalized form */
int i;
int mindepth = a->depth > b->depth ? b->depth : a->depth;
struct bitfield *nbf = safe_calloc(sizeof(struct bitfield), 1);
nbf->bits = safe_calloc(sizeof(bitpattern), a->depth);
nbf->depth = a->depth;
for (i = 0; i < mindepth; i++) {
nbf->bits[i] = a->bits[i] & ~(a->bits[i] & b->bits[i]);
}
for (;i < a->depth ; i++ ) {
nbf->bits[i] = a->bits[i];
}
for (;i < b->depth ; i++ ) {
nbf->bits[i] = b->bits[i];
}
return bf_normalize(nbf);
}
struct bitfield *
bf_normalize(struct bitfield *bf)
{
/* pack down the bits depthwise*/
if (bf != NULL) {
int i,j;
bitpattern *tbits = safe_calloc(sizeof(bitpattern), bf->depth);
bitpattern t;
for (i = 0; i < bf->depth; i++) {
t = 0;
for (j = 0; j < bf->depth; j++) {
t |= bf->bits[j];
}
tbits[i] = t;
if (t != 0) {
for (j = 0; (t != 0) && (j < bf->depth); j++) {
bitpattern p;
p = ~(t & bf->bits[j]);
t &= p;
bf->bits[j] &= p;
}
} else {
/* we have less depth than we started with */
bf->depth = i;
break;
}
}
free(bf->bits);
bf->bits = tbits;
}
return bf;
}
UChar *
make_alphabet(const UChar *source)
{
UChar *dest;
int sourcelen = u_strlen(source);
int x, y;
dest = safe_calloc(sourcelen + 1, sizeof(UChar));
u_strcpy(dest, source);
/* Very simple ripple sort as these are very short strings */
/* No advantage in using qsort() or similar */
for (x = 0; x < sourcelen - 1; x++) {
for (y = x + 1; y < sourcelen ; y++) {
if (dest[x] > dest[y]) {
UChar temp;
temp = dest[x];
dest[x] = dest[y];
dest[y] = temp;
}
}
}
x = y = 0;
while (dest[x]) {
if (dest[x] != dest[y])
dest[++y] = dest[x];
x++;
}
dest[++y] = dest[x];
return dest;
}
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