bitmap: Add first cut at a bitmap module

This adds a module for manipulating bitmaps, based on the API from the
Linux kernel's bitmap.h.  So far it's missing the trickier bits, but is
a little more flexible, allowing bitmaps that don't have to be contained
in an integer number of unsigned longs.
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>

ccan/bitmap/LICENSE

+../../licenses/LGPL-2.1
\ No newline at end of file

ccan/bitmap/_info

+#include <string.h>
+#include "config.h"
+
+/**
+ * bitmap - bitmap handling
+ *
+ * This code handles manipulation of bitmaps, arbitrary length arrays
+ * of bits.
+ *
+ * License: LGPL (v2.1 or any later version)
+ * Author: David Gibson <david@gibson.dropbear.id.au>
+ */
+int main(int argc, char *argv[])
+{
+	/* Expect exactly one argument */
+	if (argc != 2)
+		return 1;
+
+	if (strcmp(argv[1], "depends") == 0) {
+		return 0;
+	}
+
+        if (strcmp(argv[1], "testdepends") == 0) {
+                printf("ccan/array_size\n");
+                return 0;
+        }
+
+	return 1;
+}

ccan/bitmap/bitmap.h

+/* Licensed under LGPLv2+ - see LICENSE file for details */
+#ifndef CCAN_BITMAP_H_
+#define CCAN_BITMAP_H_
+
+#include <stdbool.h>
+#include <stdlib.h>
+#include <string.h>
+
+#define BITS_PER_LONG	(sizeof(unsigned long) * 8)
+
+#define BYTE(_bm, _n)	(((unsigned char *)(_bm))[(_n) / 8])
+#define LONG(_bm, _n)	(((unsigned long *)(_bm))[(_n) / BITS_PER_LONG])
+#define BIT(_n)		(0x80 >> ((_n) % 8))
+
+#define BYTES(_nbits)	((_nbits) / 8)
+#define BITS(_nbits)	((~(0xff >> ((_nbits) % 8))) & 0xff)
+
+static inline void bitmap_set_bit(void *bitmap, int n)
+{
+	BYTE(bitmap, n) |= BIT(n);
+}
+
+static inline void bitmap_clear_bit(void *bitmap, int n)
+{
+	BYTE(bitmap, n) &= ~BIT(n);
+}
+
+static inline void bitmap_change_bit(void *bitmap, int n)
+{
+	BYTE(bitmap, n) ^= BIT(n);
+}
+
+static inline bool bitmap_test_bit(void *bitmap, int n)
+{
+	return !!(BYTE(bitmap, n) & BIT(n));
+}
+
+
+static inline void bitmap_zero(void *bitmap, int nbits)
+{
+	memset(bitmap, 0, BYTES(nbits));
+	if (BITS(nbits))
+		BYTE(bitmap, nbits) &= ~BITS(nbits);
+}
+
+static inline void bitmap_fill(void *bitmap, int nbits)
+{
+	memset(bitmap, 0xff, BYTES(nbits));
+	if (BITS(nbits))
+		BYTE(bitmap, nbits) |= BITS(nbits);
+}
+
+static inline void bitmap_copy(void *dst, void *src, int nbits)
+{
+	memcpy(dst, src, BYTES(nbits));
+	if (BITS(nbits)) {
+		BYTE(dst, nbits) &= ~BITS(nbits);
+		BYTE(dst, nbits) |= BYTE(src, nbits) & BITS(nbits);
+	}
+}
+
+#define DEF_BINOP(_name, _op) \
+	static inline void bitmap_##_name(void *dst, void *src1, void *src2, \
+					 int nbits) \
+	{ \
+		int n = 0; \
+		while ((nbits - n) >= BITS_PER_LONG) { \
+			LONG(dst, n) = LONG(src1, n) _op LONG(src2, n); \
+			n += BITS_PER_LONG; \
+		} \
+		while ((nbits - n) >= 8) { \
+			BYTE(dst, n) = BYTE(src1, n) _op BYTE(src2, n); \
+			n += 8; \
+		} \
+		if (BITS(nbits)) { \
+			BYTE(dst, nbits) &= ~BITS(nbits); \
+			BYTE(dst, nbits) |= (BYTE(src1, nbits) _op BYTE(src2, nbits)) \
+				& BITS(nbits); \
+		} \
+	}
+
+DEF_BINOP(and, &)
+DEF_BINOP(or, |)
+DEF_BINOP(xor, ^)
+DEF_BINOP(andnot, & ~)
+
+#undef DEF_BINOP
+
+static inline void bitmap_complement(void *dst, void *src, int nbits)
+{
+	int n = 0;
+
+	while ((nbits - n) >= BITS_PER_LONG) {
+		LONG(dst, n) = ~LONG(src, n);
+		n += BITS_PER_LONG;
+	}
+	while ((nbits - n) >= 8) {
+		BYTE(dst, n) = ~BYTE(src, n);
+		n += 8;
+	}
+	if (BITS(nbits)) {
+		BYTE(dst, nbits) &= ~BITS(nbits);
+		BYTE(dst, nbits) |= ~BYTE(src, nbits) & BITS(nbits);
+	}
+}
+
+static inline bool bitmap_equal(void *src1, void *src2, int nbits)
+{
+	if (memcmp(src1, src2, BYTES(nbits)) != 0)
+		return false;
+	if ((BYTE(src1, nbits) & BITS(nbits))
+	    != (BYTE(src2, nbits) & BITS(nbits)))
+		return false;
+	return true;
+}
+
+static inline bool bitmap_intersects(void *src1, void *src2, int nbits)
+{
+	int n = 0;
+
+	while ((nbits - n) >= BITS_PER_LONG) {
+		if (LONG(src1, n) & LONG(src2, n))
+			return true;
+		n += BITS_PER_LONG;
+	}
+	while ((nbits - n) >= 8) {
+		if (BYTE(src1, n) & BYTE(src2, n))
+			return true;
+		n += 8;
+	}
+	if (BITS(nbits) & BYTE(src1, nbits) & BYTE(src2, nbits)) {
+		return true;
+	}
+	return false;
+}
+
+static inline bool bitmap_subset(void *src1, void *src2, int nbits)
+{
+	int n = 0;
+
+	while ((nbits - n) >= BITS_PER_LONG) {
+		if (LONG(src1, n) & ~LONG(src2, n))
+			return false;
+		n += BITS_PER_LONG;
+	}
+	while ((nbits - n) >= 8) {
+		if (BYTE(src1, n) & ~BYTE(src2, n))
+			return false;
+		n += 8;
+	}
+	if (BITS(nbits) & (BYTE(src1, nbits) & ~BYTE(src2, nbits))) {
+		return false;
+	}
+	return true;
+}
+
+static inline bool bitmap_full(void *bitmap, int nbits)
+{
+	int n = 0;
+
+	while ((nbits - n) >= BITS_PER_LONG) {
+		if (LONG(bitmap, n) != -1UL)
+			return false;
+		n += BITS_PER_LONG;
+	}
+	while ((nbits - n) >= 8) {
+		if (BYTE(bitmap, n) != 0xff)
+			return false;
+		n += 8;
+	}
+	if (BITS(nbits)
+	    && ((BITS(nbits) & BYTE(bitmap, nbits)) != BITS(nbits))) {
+		return false;
+	}
+	return true;
+}
+
+static inline bool bitmap_empty(void *bitmap, int nbits)
+{
+	int n = 0;
+
+	while ((nbits - n) >= BITS_PER_LONG) {
+		if (LONG(bitmap, n))
+			return false;
+		n += BITS_PER_LONG;
+	}
+	while ((nbits - n) >= 8) {
+		if (BYTE(bitmap, n))
+			return false;
+		n += 8;
+	}
+	if (BITS(nbits) && ((BITS(nbits) & BYTE(bitmap, nbits)))) {
+		return false;
+	}
+	return true;
+}
+
+
+static inline void *bitmap_alloc(int nbits)
+{
+	return malloc((nbits + 7) / 8);
+}
+
+#undef BYTE
+#undef LONG
+#undef BIT
+#undef BYTES
+#undef BITS
+
+#endif /* CCAN_BITMAP_H_ */

ccan/bitmap/test/run.c

+#include <ccan/bitmap/bitmap.h>
+#include <ccan/tap/tap.h>
+#include <ccan/array_size/array_size.h>
+
+int bitmap_sizes[] = {
+	1, 2, 3, 4, 5, 6, 7, 8,
+	16, 17, 24, 32, 33,
+	64, 65, 127, 128, 129,
+	1023, 1024, 1025,
+};
+#define NSIZES ARRAY_SIZE(bitmap_sizes)
+#define NTESTS 9
+
+static void test_sizes(int nbits)
+{
+	void *bitmap = bitmap_alloc(nbits);
+	int i, j;
+	bool wrong;
+
+	ok1(bitmap != NULL);
+
+	bitmap_zero(bitmap, nbits);
+	wrong = false;
+	for (i = 0; i < nbits; i++) {
+		wrong = wrong || bitmap_test_bit(bitmap, i);
+	}
+	ok1(!wrong);
+
+	bitmap_fill(bitmap, nbits);
+	wrong = false;
+	for (i = 0; i < nbits; i++) {
+		wrong = wrong || !bitmap_test_bit(bitmap, i);
+	}
+	ok1(!wrong);
+
+	wrong = false;
+	for (i = 0; i < nbits; i++) {
+		bitmap_zero(bitmap, nbits);
+		bitmap_set_bit(bitmap, i);
+		for (j = 0; j < nbits; j++) {
+			bool val = (i == j);
+
+			wrong = wrong || (bitmap_test_bit(bitmap, j) != val);
+		}
+	}
+	ok1(!wrong);
+
+	wrong = false;
+	for (i = 0; i < nbits; i++) {
+		bitmap_fill(bitmap, nbits);
+		bitmap_clear_bit(bitmap, i);
+		for (j = 0; j < nbits; j++) {
+			bool val = !(i == j);
+
+			wrong = wrong || (bitmap_test_bit(bitmap, j) != val);
+		}
+	}
+	ok1(!wrong);
+
+	bitmap_zero(bitmap, nbits);
+	ok1(bitmap_empty(bitmap, nbits));
+
+	wrong = false;
+	for (i = 0; i < nbits; i++) {
+		bitmap_zero(bitmap, nbits);
+		bitmap_set_bit(bitmap, i);
+		wrong = wrong || bitmap_empty(bitmap, nbits);
+	}
+	ok1(!wrong);
+
+	bitmap_fill(bitmap, nbits);
+	ok1(bitmap_full(bitmap, nbits));
+
+	wrong = false;
+	for (i = 0; i < nbits; i++) {
+		bitmap_fill(bitmap, nbits);
+		bitmap_clear_bit(bitmap, i);
+		wrong = wrong || bitmap_full(bitmap, nbits);
+	}
+	ok1(!wrong);
+		
+	free(bitmap);
+}
+
+int main(void)
+{
+	int i;
+
+	/* This is how many tests you plan to run */
+	plan_tests(NSIZES * NTESTS);
+
+	for (i = 0; i < NSIZES; i++) {
+		diag("Testing %d-bit bitmap", bitmap_sizes[i]);
+		test_sizes(bitmap_sizes[i]);
+	}
+
+	/* This exits depending on whether all tests passed */
+	return exit_status();
+}