Class new title: LargeInteger
	subclassof: Number
	fields: 'bytes	"A Natural number (digits are 0 to 255)"
				 neg	"The sign" '
	declare: '';
	sharing: BitMasks


 t1 
	[(self compare: t1) < 3  [self]
	false]

 t1 
	[(self compare: t1) > 1  [self]
	false]

* t1 | t2 t3 
	[t2 _ t1 neg.
	t3 _ bytes nattimes: t1 bytes.
	LargeInteger new bytes: t3 neg: neg  t2  false]

+ t1 | t2 t3 
	[t2 _ t1 neg.
	neg  t2 
		[t3 _ bytes natadd: t1 bytes.
		LargeInteger new bytes: t3 neg: neg]
	t3 _ bytes natsubtract: t1 bytes.
	neg  [t3 negate]
	t3]

- t1 | t2 t3 
	[t2 _ t1 neg.
	neg  t2 
		[t3 _ bytes natsubtract: t1 bytes.
		neg  [t3 neg_ t3 neg  false]
		t3]
	t3 _ bytes natadd: t1 bytes.
	LargeInteger new bytes: t3 neg: neg]

/ t1 
	[((self intdiv: t1)  1) asInteger]

< t1 
	[(self compare: t1) = 1  [self]
	false]

= t1 
	[t1 isNumber 
		[(self compare: t1) = 2  [self]
		false]
	false]

> t1 
	[(self compare: t1) = 3  [self]
	false]

\ t1 
	[(self intdiv: t1)  2]

abs 
	[LargeInteger new bytes: bytes neg: false]

allmask: t1 
	[t1 = (self land: t1)]

anymask: t1 
	[0  (self land: t1)]

asFloat 
	[self asString asFloat]

asInt16 | t1 
	[t1 _ bytes  1.
	[bytes length > 1  [t1 _ (bytes  2 lshift: 8) + t1]].
	neg 
		[t1 = 0 minVal  [t1]
		0 - t1]
	t1]

asInteger 
	[self canBeSmall  [self asSmall]
	self]

asLarge

asSmall | t1 t2 
	[t1 _ bytes  1.
	[bytes length > 1 
		[t2 _ bytes  2.
		t1 _ ([NoteTaker  [(t2 land: 63) - (t2 land: 64)]
				t2] lshift: 8) + t1]].
	neg 
		[t1 = 0 minVal  [t1]
		0 - t1]
	t1]

bit: t1 | t2 
	[t2 _ bytes  (1 + (t1 - 1 / 8)).
	(t2 lshift: 0 - (t1 - 1 \ 8)) land: 1]

bits: t1 to: t2 | t3 t4 
	[t3 _ t2 - t1 + 1.
	t4 _ [t3 < 15  [biton  (t3 + 1) - 1]
			t3 = 15  [32767]
			1].
	(self lshift: t2 - 15) land: t4]

bits: t1 to: t2 _ t3 | t4 t5 
	[t4 _ t2 - t1 + 1.
	t5 _ [t4 < 15  [biton  (t4 + 1) - 1]
			t4 = 15  [32767]
			1].
	(self land: ((t5 lshift: 15 - t2) lxor: 1)) lor: ((t3 land: t5) lshift: 15 - t2)]

bytes [bytes]

bytes: t1 neg: t2 
	[bytes _ t1.
	neg _ t2.
	while bytes isLarge do
		[bytes _ bytes bytes]]

canBeInt16 | t1  
	[[bytes length > 2  [for t1 from: 3 to: bytes length do
			[bytes  t1  0  [false]]]].
	self 
 32767 and self  32768  [true]
	false]

canBeSmall | t1  
	[[bytes length > 2  [for t1 from: 3 to: bytes length do
			[bytes  t1  0  [false]]]].
	self 
 1 maxVal and self  1 minVal  [true]
	false]

compare: t1 | t2 t3 
	[((bytes length = 1 and bytes  1 = 0) and t1 bytes length = 1) and t1 bytes  1 = 0  [2]
	neg 
		[t1 neg  [t1 bytes natcompare: bytes]
		1]
	t1 neg  [3]
	bytes natcompare: t1 bytes]

even 
	[(bytes  1 land: 1) = 0]

field: t1 | t2 
	[t2 _ 15 - (t1 land: 15).
	self bits: t2 - (t1 / 16) + 1 to: t2]

field: t1 _ t2 | t3 
	[t3 _ 15 - (t1 land: 15).
	self bits: t3 - (t1 / 16) + 1 to: t3 _ t2]

hibit 
	[bytes last hibit + (8 * (bytes length - 1))]

intdiv: t1 | t2 t3 t4 t5 t6 
	[t5 _ bytes natdiv: t1 bytes.
	t2 _ t5  1.
	t3 _ (t5  2) asInteger.
	t4 _ neg  t1 neg  false.
	[t2 last = 0 
		[t2 length < 2  []
		t2 _ t2 growby: 1]].
	t5  1 _ LargeInteger new bytes: t2 neg: t4.
	t5  2 _ [t4 and 0  t3  [t1 abs - t3]
	t3].
	t5]

isLarge

land: t1 | t2 t3 t4 
	[NoteTaker 
		[t2 _ self logicArg bytes.
		t3 _ t1 asLarge logicArg bytes.
		t4 _ Natural new: 2.
		t4  1 _ t2  1 land: t3  1.
		t4  2 _ t2  2 land: t3  2.
		(LargeInteger new bytes: t4 neg: false) logicUnArg]
	self asSmall land: t1]

logicArg | t1 t2 t3 
	[neg 
		[t1 _ Natural new: 2.
		t2 _ (bytes  1 lxor: 255) + 1.
		t1  1 _ t2 land: 255.
		t2 _ t2 lshift: 8.
		t1  2 _ (bytes  2 lxor: 255) + t2 land: 255.
		LargeInteger new bytes: t1 neg: false]]

logicUnArg | t1 
	[bytes length  2  [user notify: 'not logic arg']
	(bytes  2 land: 128)  0 
		[t1 _ (bytes  1 lxor: 255) + 1.
		bytes  1 _ t1 land: 255.
		t1 _ t1 lshift: 8.
		bytes  2 _ (bytes  2 lxor: 255) + t1 land: 255.
		neg _ true]
	self asInt16]

lor: t1 | t2 t3 t4 
	[NoteTaker 
		[t2 _ self logicArg.
		t3 _ t1 asLarge logicArg.
		t4 _ Natural new: 2.
		t4  1 _ t2  1 lor: t3  1.
		t4  2 _ t2  2 lor: t3  2.
		(LargeInteger new bytes: t4 neg: false) logicUnArg]
	self asSmall lor: t1]

lshift: t1 | t2 t3 t4 t5 t6 
	[NoteTaker 
		[t2 _ self logicArg.
		t3 _ Natural new: 2.
		t3  1 _ t2 bytes  1.
		t3  2 _ t2 bytes  2.
		t2 bytes: t3 neg: false.
		t6 _ t1 abs.
		t6  16  [0]
		t4 _ t6 / 2.
		t5 _ t6 - t4.
		t4 _ 1 lshift: t4.
		t5 _ 1 lshift: t5.
		t6 _ t4 asLarge * t5 asLarge.
		t2 _ [t1 < 0  [t2 / t6]
				t2 * t6].
		t3 _ Natural new: 2.
		t3  1 _ t2 bytes  1.
		t3  2 _ t2 bytes  2.
		(LargeInteger new bytes: t3 neg: false) logicUnArg]
	self asSmall lshift: t1]

ltand: t1 | t2 t3 t4 
	[t2 _ self logicArg bytes.
	t3 _ t1 asLarge logicArg bytes.
	t4 _ Natural new: 2.
	t4  1 _ t2  1 land: t3  1.
	t4  2 _ t2  2 land: t3  2.
	(LargeInteger new bytes: t4 neg: false) logicUnArg]

lxor: t1 | t2 t3 t4 
	[NoteTaker 
		[t2 _ self logicArg.
		t3 _ t1 asLarge logicArg.
		t4 _ Natural new: 2.
		t4  1 _ t2  1 lxor: t3  1.
		t4  2 _ t2  2 lxor: t3  2.
		(LargeInteger new bytes: t4 neg: false) logicUnArg]
	self asSmall lxor: t1]

neg [neg]

neg_ t1 
	[neg _ t1]

negate 
	[LargeInteger new bytes: bytes neg: neg  false]

negated 
	[LargeInteger new bytes: bytes neg: neg  false]

nomask: t1 
	[0 = (self land: t1)]

printon: t1 base: t2 
	[[neg  [t1 append: '']].
	bytes printon: t1 base: t2]