bitmap: Extend allocation functions

The bitmap module already has a simple allocation helper, which returns
an uninitialized, dynamically allocated bitmap of a given size.

This extends this with bitmap_alloc[01]() which allocate bitmaps and
initialize them to all zero or all one.

It also adds bitmap_realloc[01]() which reallocate an existing bitmap,
preserving existing bits, and setting any new bits to all zero or all one.

Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>

ccan/bitmap/bitmap.h

@@ -30,11 +30,6 @@ static inline size_t bitmap_sizeof(unsigned long nbits)
 	return BITMAP_NWORDS(nbits) * sizeof(bitmap_word);
 }
 
-static inline bitmap *bitmap_alloc(unsigned long nbits)
-{
-	return malloc(bitmap_sizeof(nbits));
-}
-
 static inline bitmap_word bitmap_bswap(bitmap_word w)
 {
 	if (BITMAP_WORD_BITS == 32)
@@ -192,4 +187,52 @@ static inline bool bitmap_empty(const bitmap *bitmap, unsigned long nbits)
 	return true;
 }
 
+/*
+ * Allocation functions
+ */
+static inline bitmap *bitmap_alloc(unsigned long nbits)
+{
+	return malloc(bitmap_sizeof(nbits));
+}
+
+static inline bitmap *bitmap_alloc0(unsigned long nbits)
+{
+	bitmap *bitmap;
+
+	bitmap = bitmap_alloc(nbits);
+	bitmap_zero(bitmap, nbits);
+	return bitmap;
+}
+
+static inline bitmap *bitmap_alloc1(unsigned long nbits)
+{
+	bitmap *bitmap;
+
+	bitmap = bitmap_alloc(nbits);
+	bitmap_fill(bitmap, nbits);
+	return bitmap;
+}
+
+static inline bitmap *bitmap_realloc0(bitmap *bitmap,
+				      unsigned long obits, unsigned long nbits)
+{
+	bitmap = realloc(bitmap, bitmap_sizeof(nbits));
+
+	if (nbits > obits)
+		bitmap_zero_range(bitmap, obits, nbits);
+
+	return bitmap;
+}
+
+static inline bitmap *bitmap_realloc1(bitmap *bitmap,
+				      unsigned long obits, unsigned long nbits)
+{
+	bitmap = realloc(bitmap, bitmap_sizeof(nbits));
+
+	if (nbits > obits)
+		bitmap_fill_range(bitmap, obits, nbits);
+
+	return bitmap;
+}
+
 #endif /* CCAN_BITMAP_H_ */

ccan/bitmap/test/run-alloc.c

@@ -0,0 +1,101 @@
+#include <ccan/bitmap/bitmap.h>
+#include <ccan/tap/tap.h>
+#include <ccan/array_size/array_size.h>
+#include <ccan/foreach/foreach.h>
+
+#include <ccan/bitmap/bitmap.c>
+
+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_BASE 4
+#define NTESTS_REALLOC 10
+
+static void test_basic_alloc(int nbits)
+{
+	bitmap *bitmap;
+
+	bitmap = bitmap_alloc0(nbits);
+	ok1(bitmap != NULL);
+	ok1(bitmap_empty(bitmap, nbits));
+
+	free(bitmap);
+
+	bitmap = bitmap_alloc1(nbits);
+	ok1(bitmap != NULL);
+	ok1(bitmap_full(bitmap, nbits));
+
+	free(bitmap);
+}
+
+static void test_realloc(int obits, int nbits)
+{
+	bitmap *bitmap;
+	int i;
+	bool wrong;
+
+	bitmap = bitmap_alloc0(obits);
+	ok1(bitmap != NULL);
+	ok1(bitmap_empty(bitmap, obits));
+
+	bitmap = bitmap_realloc1(bitmap, obits, nbits);
+	ok1(bitmap != NULL);
+	if (obits < nbits)
+		ok1(bitmap_empty(bitmap, obits));
+	else
+		ok1(bitmap_empty(bitmap, nbits));
+
+	wrong = false;
+	for (i = obits; i < nbits; i++)
+		wrong = wrong || !bitmap_test_bit(bitmap, i);
+	ok1(!wrong);
+
+	free(bitmap);
+
+	bitmap = bitmap_alloc1(obits);
+	ok1(bitmap != NULL);
+	ok1(bitmap_full(bitmap, obits));
+
+	bitmap = bitmap_realloc0(bitmap, obits, nbits);
+	ok1(bitmap != NULL);
+	if (obits < nbits)
+		ok1(bitmap_full(bitmap, obits));
+	else
+		ok1(bitmap_full(bitmap, nbits));
+
+	wrong = false;
+	for (i = obits; i < nbits; i++)
+		wrong = wrong || bitmap_test_bit(bitmap, i);
+	ok1(!wrong);
+
+	free(bitmap);
+}
+
+int main(void)
+{
+	int i, j;
+
+	/* This is how many tests you plan to run */
+	plan_tests(NSIZES * NTESTS_BASE + NSIZES * NSIZES * NTESTS_REALLOC);
+
+	for (i = 0; i < NSIZES; i++) {
+		diag("Testing %d-bit bitmap", bitmap_sizes[i]);
+		test_basic_alloc(bitmap_sizes[i]);
+	}
+
+	for (i = 0; i < NSIZES; i++) {
+		for (j = 0; j < NSIZES; j++) {
+			diag("Testing %d-bit => %d-bit bitmap",
+			     bitmap_sizes[i], bitmap_sizes[j]);
+
+			test_realloc(bitmap_sizes[i], bitmap_sizes[j]);
+		}
+	}
+
+	/* This exits depending on whether all tests passed */
+	return exit_status();
+}