StackHash

A hash table that allocates its memory on RegionAllocator. Good for building a temporary hash tables that will not escape the current scope.

struct StackHash (

) {

this(size_t nElem, RegionAllocator alloc);

V opIndex(K key);

V opIndexAssign(V val, K key);

V* opBinaryRight(K key);

void remove(K key);

auto keys();

auto values();

size_t length [@property getter];

V get(K key, V defaultValue);

}

Constructors

this this(size_t nElem, RegionAllocator alloc): Due to the nature of RegionAllocator, you must specify on object creation * the approximate number of elements your table will have. Too large a * number will waste space and incur poor cache performance. Too low a * number will make this struct perform like a linked list. Generally, * if you're building a table from some other range, some fraction of the * size of that range is a good guess.

Members

Functions

get V get(K key, V defaultValue): Attempt to look up a key and return a default value if the key is not present.
keys auto keys(): Returns a forward range to iterate over the keys of this table. * The lifetime of this range must not exceed the lifetime of this * StackHash.
opBinaryRight V* opBinaryRight(K key)
opIndex V opIndex(K key): Index an element of the range. If it does not exist, it will be created * and initialized to V.init.
opIndexAssign V opIndexAssign(V val, K key)
remove void remove(K key)
values auto values(): Returns a forward range to iterate over the values of this table. * The lifetime of this range must not exceed the lifetime of this * StackHash.

Properties

length size_t length [@property getter]

Examples

auto alloc = newRegionAllocator();
auto ss = StackHash!(uint)(5, alloc);
foreach(i; 0..5) {
    ss[i]++;
}
assert(ss[3] == 1);

Warning: This implementation places removed nodes on an internal free list and recycles them, since there is no way to delete RegionAllocator-allocated data in a non-LIFO order. Therefore, you may not retain the address of a variable stored in a StackHash after deleting it from the StachHash. For example, DO NOT do this:

SomeType* myPtr = &(myStackHash["foo"]);
myStackHash.remove("foo");
*myPtr = someValue;

The OpenD Programming Language