diff options
Diffstat (limited to 'src/include/lib')
| -rw-r--r-- | src/include/lib/pairingheap.h | 19 |
1 files changed, 19 insertions, 0 deletions
diff --git a/src/include/lib/pairingheap.h b/src/include/lib/pairingheap.h index a7f28ec422d..e3e320fc434 100644 --- a/src/include/lib/pairingheap.h +++ b/src/include/lib/pairingheap.h @@ -30,6 +30,25 @@ typedef struct pairingheap_node } pairingheap_node; /* + * Return the containing struct of 'type' where 'membername' is the + * pairingheap_node pointed at by 'ptr'. + * + * This is used to convert a pairingheap_node * back to its containing struct. + */ +#define pairingheap_container(type, membername, ptr) \ + (AssertVariableIsOfTypeMacro(ptr, pairingheap_node *), \ + AssertVariableIsOfTypeMacro(((type *) NULL)->membername, pairingheap_node), \ + ((type *) ((char *) (ptr) - offsetof(type, membername)))) + +/* + * Like pairingheap_container, but used when the pointer is 'const ptr' + */ +#define pairingheap_const_container(type, membername, ptr) \ + (AssertVariableIsOfTypeMacro(ptr, const pairingheap_node *), \ + AssertVariableIsOfTypeMacro(((type *) NULL)->membername, pairingheap_node), \ + ((const type *) ((const char *) (ptr) - offsetof(type, membername)))) + +/* * For a max-heap, the comparator must return <0 iff a < b, 0 iff a == b, * and >0 iff a > b. For a min-heap, the conditions are reversed. */ |