1 files changed, 66 insertions, 0 deletions
diff --git a/src/bitset.c b/src/bitset.c
new file mode 100644
index 00000000..e40bea04
--- /dev/null
+++ b/src/bitset.c
@@ -0,0 +1,66 @@
+#include <limits.h>
+#include <stdlib.h>
+#include <string.h>
+#include <assert.h>
+
+#include "bitset.h"
+#include "buffer.h"
+
+#define BITSET_BITS \
+	( CHAR_BIT * sizeof(size_t) )
+
+#define BITSET_MASK(pos) \
+	( ((size_t)1) << ((pos) % BITSET_BITS) )
+
+#define BITSET_WORD(set, pos) \
+	( (set)->bits[(pos) / BITSET_BITS] )
+
+#define BITSET_USED(nbits) \
+	( ((nbits) + (BITSET_BITS - 1)) / BITSET_BITS )
+
+bitset *bitset_init(size_t nbits) {
+	bitset *set;
+
+	set = malloc(sizeof(*set));
+	assert(set);
+
+	set->bits = calloc(BITSET_USED(nbits), sizeof(*set->bits));
+	set->nbits = nbits;
+
+	assert(set->bits);
+
+	return set;
+}
+
+void bitset_reset(bitset *set) {
+	memset(set->bits, 0, BITSET_USED(set->nbits) * sizeof(*set->bits));
+}
+
+void bitset_free(bitset *set) {
+	free(set->bits);
+	free(set);
+}
+
+void bitset_clear_bit(bitset *set, size_t pos) {
+	if (pos >= set->nbits) {
+	    SEGFAULT();
+	}
+
+	BITSET_WORD(set, pos) &= ~BITSET_MASK(pos);
+}
+
+void bitset_set_bit(bitset *set, size_t pos) {
+	if (pos >= set->nbits) {
+	    SEGFAULT();
+	}
+
+	BITSET_WORD(set, pos) |= BITSET_MASK(pos);
+}
+
+int bitset_test_bit(bitset *set, size_t pos) {
+	if (pos >= set->nbits) {
+	    SEGFAULT();
+	}
+
+	return (BITSET_WORD(set, pos) & BITSET_MASK(pos)) != 0;
+}