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/*
* libmowgli: A collection of useful routines for programming.
* mowgli_bitvector.c: Bitvectors.
*
* Copyright (c) 2007 William Pitcock <nenolod -at- sacredspiral.co.uk>
*
* Permission to use, copy, modify, and/or distribute this software for any
* purpose with or without fee is hereby granted, provided that the above
* copyright notice and this permission notice is present in all copies.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
* WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
* DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT,
* INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
* (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
* SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
* STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
* IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*/
#include "mowgli.h"
static mowgli_object_class_t klass;
/*
* mowgli_bitvector_init(void)
*
* Initialization code for the mowgli.bitvector library.
*
* Inputs:
* - none
*
* Outputs:
* - none
*
* Side Effects:
* - the mowgli_bitvector_t object class is registered.
*/
void mowgli_bitvector_init(void)
{
mowgli_object_class_init(&klass, "mowgli_bitvector_t", mowgli_free, FALSE);
}
/*
* mowgli_bitvector_create(int bits)
*
* Creates a bitvector.
*
* Inputs:
* - amount of bits that the bitvector should store
*
* Outputs:
* - a mowgli.bitvector object
*
* Side Effects:
* - none
*/
mowgli_bitvector_t *mowgli_bitvector_create(int bits)
{
mowgli_bitvector_t *bv = (mowgli_bitvector_t *) mowgli_alloc(sizeof(mowgli_bitvector_t));
mowgli_object_init(mowgli_object(bv), "mowgli_bitvector_t", &klass, NULL);
bv->bits = bits;
bv->divisor = sizeof(int);
bv->vector = (unsigned int *) mowgli_alloc_array(bv->divisor, bv->bits / bv->divisor);
return bv;
}
/*
* mowgli_bitvector_set(mowgli_bitvector_t *bv, int slot, mowgli_boolean_t val)
*
* Sets a bit either ON or OFF in the bitvector.
*
* Inputs:
* - a mowgli bitvector object
* - a slot
* - the value for that slot
*
* Outputs:
* - nothing
*
* Side Effects:
* - a bit is either set ON or OFF in the bitvector.
*/
void mowgli_bitvector_set(mowgli_bitvector_t *bv, int slot, mowgli_boolean_t val)
{
int value = 1 << slot;
switch(val)
{
case FALSE:
bv->vector[bv->bits / bv->divisor] &= ~value;
break;
default:
case TRUE:
bv->vector[bv->bits / bv->divisor] |= value;
break;
}
}
/*
* mowgli_bitvector_get(mowgli_bitvector_t *bv, int slot)
*
* Returns whether the bit in a given slot is ON or OFF.
*
* Inputs:
* - a mowgli.bitvector object
* - a slot to lookup
*
* Outputs:
* - TRUE if the bit is on
* - FALSE otherwise
*
* Side Effects:
* - none
*/
mowgli_boolean_t mowgli_bitvector_get(mowgli_bitvector_t *bv, int slot)
{
int mask = 1 << slot;
return ((bv->vector[bv->bits / bv->divisor] & mask) != 0) ? TRUE : FALSE;
}
/*
* mowgli_bitvector_combine(mowgli_bitvector_t *bv1, mowgli_bitvector_t *bv2)
*
* Combines two bitvectors together.
*
* Inputs:
* - two bitvectors to be combined
*
* Outputs:
* - a new bitvector containing the combined result.
*
* Side Effects:
* - none
*/
mowgli_bitvector_t *mowgli_bitvector_combine(mowgli_bitvector_t *bv1, mowgli_bitvector_t *bv2)
{
int bits, iter, bs;
mowgli_bitvector_t *out;
return_val_if_fail(bv1 != NULL, NULL);
return_val_if_fail(bv2 != NULL, NULL);
/* choose the larger bitwidth */
bits = bv1->bits > bv2->bits ? bv1->bits : bv2->bits;
/* create the third bitvector. */
out = mowgli_bitvector_create(bits);
/* cache the size of the bitvector in memory. */
bs = out->bits / out->divisor;
for (iter = 0; iter < bs; iter++)
{
out->vector[iter] |= bv1->vector[iter];
out->vector[iter] |= bv2->vector[iter];
}
return out;
}
/*
* mowgli_bitvector_xor(mowgli_bitvector_t *bv1, mowgli_bitvector_t *bv2)
*
* XORs two bitvectors together.
*
* Inputs:
* - two bitvectors to be XORed
*
* Outputs:
* - a new bitvector containing the XORed result.
*
* Side Effects:
* - none
*/
mowgli_bitvector_t *mowgli_bitvector_xor(mowgli_bitvector_t *bv1, mowgli_bitvector_t *bv2)
{
int bits, iter, bs;
mowgli_bitvector_t *out;
return_val_if_fail(bv1 != NULL, NULL);
return_val_if_fail(bv2 != NULL, NULL);
/* choose the larger bitwidth */
bits = bv1->bits > bv2->bits ? bv1->bits : bv2->bits;
/* create the third bitvector. */
out = mowgli_bitvector_create(bits);
/* cache the size of the bitvector in memory. */
bs = out->bits / out->divisor;
for (iter = 0; iter < bs; iter++)
{
out->vector[iter] = bv1->vector[iter];
out->vector[iter] &= ~bv2->vector[iter];
}
return out;
}
/*
* mowgli_bitvector_compare(mowgli_bitvector_t *bv1, mowgli_bitvector_t *bv2)
*
* Compares two bitvectors to each other.
*
* Inputs:
* - two bitvectors to be compared
*
* Outputs:
* - TRUE if the bitvector is equal
* - FALSE otherwise
*
* Side Effects:
* - none
*/
mowgli_boolean_t mowgli_bitvector_compare(mowgli_bitvector_t *bv1, mowgli_bitvector_t *bv2)
{
int iter, bs;
mowgli_boolean_t ret = TRUE;
/* cache the size of the bitvector in memory. */
bs = bv1->bits / bv1->divisor;
for (iter = 0; iter < bs; iter++)
{
if (!(bv1->vector[iter] & bv2->vector[iter]))
ret = FALSE;
}
return ret;
}
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