;
; iron_bloom.hsp — ブルームフィルタ (確率的集合)
; Pure HSP 実装。
;
#ifndef __iron_bloom_hsp__
#define __iron_bloom_hsp__
#module iron_bloom

dim _bf_bits, 1024
dim _bf_size, 1

#deffunc bloom_init int size
	_bf_size = size
	if _bf_size <= 0 : _bf_size = 8192
	dim _bf_bits, _bf_size / 32 + 1
	return

; Simple hash functions
#defcfunc _bf_hash1 str s, local h, local _bs1
	h = 5381
	_bs1 = s
	repeat strlen(s)
		h = h * 33 + peek(_bs1, cnt)
		h = h & 0x7FFFFFFF
	loop
	return h \ _bf_size

#defcfunc _bf_hash2 str s, local h, local _bs2
	h = 0
	_bs2 = s
	repeat strlen(s)
		h = h * 31 + peek(_bs2, cnt) + 1
		h = h & 0x7FFFFFFF
	loop
	return h \ _bf_size

#deffunc bloom_add str item, local h1, local h2
	h1 = _bf_hash1(item)
	h2 = _bf_hash2(item)
	_bf_bits(h1 / 32) = _bf_bits(h1 / 32) | (1 << (h1 \ 32))
	_bf_bits(h2 / 32) = _bf_bits(h2 / 32) | (1 << (h2 \ 32))
	return

#defcfunc bloom_contains str item, local h1, local h2
	h1 = _bf_hash1(item)
	h2 = _bf_hash2(item)
	if (_bf_bits(h1 / 32) & (1 << (h1 \ 32))) == 0 : return 0
	if (_bf_bits(h2 / 32) & (1 << (h2 \ 32))) == 0 : return 0
	return 1

#global
#endif