Given two bitmaps and the following code:
Bitmap *a = bitmap_new(), *b = bitmap_new();
bitmap_set(a, 1);
bitmap_clear(a);
bitmap_set(a, 0);
bitmap_set(b, 0);
These two bitmaps should now have the same bits set and they should be
equal but bitmap_equal() will return false in this case because while
bitmap_clear() resets the number of elements in the array it does not
clear the array and bitmap_set() expects the array to be cleared.
GREEDY_REALLOC0 looks at the allocated size and not the actual size so
it does not clear any memory.
Fix this by freeing the allocated memory and resetting the whole Bitmap
to an initial state in bitmap_clear().
This also adds test code for this issue.
Given two bitmaps and the following code:
Bitmap *a = bitmap_new(), *b = bitmap_new();
bitmap_set(a, 0);
bitmap_unset(a, 0);
These two bitmaps should now have the same bits set and they should be
equal but bitmap_equal() will return false in this case because the
bitmaps array in a is larger because of the bit which was previously
set.
Fix this by comparing only the bits which exists in both bitmaps and
then check that the rest of the bits (if any) is all zero.
This also adds test code for this issue.
a) use memcmp() to compare bitmaps efficiently
b) use UINT64_C() macro instead of ULL suffixes to get right suffix for
uint64_t constants
c) add a few assert()s
d) when comparing integers with 0 we generally try to make this explicit
with "!= 0".
e) remove redundant bitmap_isset() if check, as we don't have it in
bitmap_isset() either.
f) It should be fine to invoke bitmap_unset() on a NULL bitmap
No need to actually reset the bitmap, we can just truncate it back zero
size. That not only makes bitmap_clear() quicker, but also subsequent
bitmap_isclear().
Reuse the Iterator object from hashmap.h and expose a similar API.
This allows us to do
{
Iterator i;
unsigned n;
BITMAP_FOREACH(n, b, i) {
Iterator j;
unsigned m;
BITMAP_FOREACH(m, b, j) {
...
}
}
}
without getting confused. Requested by David.
