shithub: mc

ref: 8317e87e7b6f9a15ff41f9f7293ef46dc208d0d7
dir: /lib/std/test/htab.myr/

use std

const insertion = {
	/*
	var ht
	var i

	ht = std.mkht(idhash, ideq)
	/* only a few values; shouldn't trigger growth */
	for i = 0; i < 5; i++
		std.htput(ht, i, i)
	;;
	for i = 0; i < 5; i++
		std.assert(std.htgetv(ht, i, -1) == i, "returned incorrect value from hash table")
	;;

	/* and grow */
	for i = 0; i < 5000; i++
		std.htput(ht, i, i)
	;;
	for i = 0; i < 5000; i++
		std.assert(std.htgetv(ht, i, -1) == i, "returned incorrect value from hash table")
	;;
	*/
}

const deletion = {
	var ht
	var i

	ht = std.mkht(idhash, ideq)
	/* create a hash table with a few hundred values */
	for i = 0; i < 4000; i++
		std.htput(ht, i, i)
	;;
	for i = 0; i < 200; i++
		std.htdel(ht, i*2)
	;;
	for i = 0; i < 200; i++
		std.assert(!std.hthas(ht, i*2), "deleted item still present")
	;;
	for i = 0; i < 200; i++
		std.assert(std.hthas(ht, i*2+1), "undeleted item missing")
	;;
	for i = 400; i < 4000; i++
		std.assert(std.hthas(ht, i), "undeleted item missing")
	;;

}

const collision = {
	var ht
	var i

	ht = std.mkht(idhash, ideq)
	/* insert an element a few hundred times */
	for i = 0; i < 500; i++
		std.htput(ht, 0, i)
	;;
	std.assert(std.hthas(ht, 0), "inserted element not present")
	std.assert(std.htgetv(ht, 0, -1) == 499, "inserted element has wrong value")
	std.htdel(ht, 0)
	std.assert(!std.hthas(ht, 0), "element left in table")
}

const tombstonefill = {
	var ht
	var i

	ht = std.mkht(idhash, ideq)
	/* 
	insert an element into each slot in the hash table, and
	delete it. With direct hashing, this is guaranteed to have
	put a tombstone into each slot.
	*/
	for i = 0; i <= ht.keys.len; i++
		std.htput(ht, i, i)
		std.htdel(ht, i)
	;;
	/* make sure we haven't actually got anything in the table */
	std.assert(ht.nelt == 0, "elements left in hash table")
	std.assert(!std.hthas(ht, 1), "found phantom element")
}

const main = {
	/* only a few elements */
	std.put("insertion\n")
	insertion()
	std.put("deletion\n")
	deletion()
	std.put("collision\n")
	collision()

	/* what happens if we try to fill everything up with tombstones? */
	tombstonefill()
}

const idhash = {x
	-> x
}

const ideq = {a, b
	-> a == b
}