Incredibly simple & super-fast sparse sets in D.
Can be used to create fixed-size maps with O(1) insertion, lookup, and removal; and lightning-fast iteration over values.
Two variants are available, with almost identical interfaces:
- Static: Implemented using static arrays. Fixed in size. Compatible with BetterC. All methods are
nothrow @nogc pure @safe. - Dynamic: Implemented with dynamic arrays. The sparse array is still fixed in size, but the dense array can grow and shrink. Incompatible with BetterC. All methods are at least
nothrow pure @safe, but some use the GC.
Documentation is provided in the library's source code. Make sure to also read a function's preconditions where applicable.
import sparse;
import std.stdio: writefln;
void main(){
StaticSparseSet!(string, 128, 64) mySet; //Can store up to 64 strings, with unique IDs 0–127.
mySet.add(12, "Twelve"); //O(1) element insertion
mySet.add(7, "Seven");
mySet.add(49, "Forty-nine");
foreach(ref element; mySet.denseElements){ //Same speed as a foreach over an array
writefln("%d: %s", element.ind, element.value);
//12: Twelve
//7: Seven
//49: Forty-nine
element.value ~= "!!";
}
mySet.remove(12); //O(1) element removal
foreach(element; mySet.denseElementsConst){ //Still the speed as a foreach over an array!
writefln("%d: %s", element.ind, element.value);
//49: Forty-nine!!
//7: Seven!!
}
if(auto valuePtr = 49 in mySet){ //O(1) element look-up (can also be done with `.has()` and then `.get()`/`.read()`)
assert(*valuePtr == "Forty-nine!!");
}
mySet.clear(); //O(1) clearing
}