text: /* vim: tabstop=4 shiftwidth=4 noexpandtab
   * This file is part of ToyOS and is released under the terms
   * of the NCSA / University of Illinois License - see LICENSE.md
   * Copyright (C) 2015 Dale Weiler
   *               2015 Kevin Lange
   */
  #include "bitset.h"
  
  #define CEIL(NUMBER, BASE) \
  	(((NUMBER) + (BASE) - 1) & ~((BASE) - 1))
  
  #define iom \
  	size_t index  = bit >> 3; \
  	bit = bit - index * 8; \
  	size_t offset = bit & 7; \
  	size_t mask   = 1 << offset;
  
  void bitset_init(bitset_t *set, size_t size) {
  	set->size = CEIL(size, 8);
  	set->data = calloc(set->size, 1);
  }
  
  void bitset_free(bitset_t *set) {
  	free(set->data);
  }
  
  static void bitset_resize(bitset_t *set, size_t size) {
  	if (set->size >= size) {
  		return;
  	}
  
  	set->data = realloc(set->data, size);
  	memset(set->data + set->size, 0, size - set->size);
  	set->size = size;
  }
  
  void bitset_set(bitset_t *set, size_t bit) {
  	iom;
  	if (set->size <= index) {
  		bitset_resize(set, set->size << 1);
  	}
  	set->data[index] |= mask;
  }
  
  int bitset_ffub(bitset_t *set) {
  	for (size_t i = 0; i < set->size * 8; i++) {
  		if (bitset_test(set, i)) {
  			continue;
  		}
  		return (int)i;
  	}
  	return -1;
  }
  
  void bitset_clear(bitset_t *set, size_t bit) {
  	iom;
  	set->data[index] &= ~mask;
  }
  
  int bitset_test(bitset_t *set, size_t bit) {
  	iom;
  	return !!(mask & set->data[index]);
  }
  
  