Tutorials:Lua:ObjectOriented - Revision history

Ajanuw: /* Calling Notation */

2020-07-18T22:52:21Z

‎Calling Notation

Dark Byte: Reverted edits by This content is not available (Talk) to last revision by Jgoemat

2019-03-18T19:09:02Z

Reverted edits by This content is not available (Talk) to last revision by Jgoemat

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This content is not available: Replaced content with 'Sorry! Content not available.'

2019-03-16T16:14:43Z

Replaced content with '<span style="font-size:25px;color:red">Sorry! Content not available.</span>'

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Jgoemat: /* Offsets */

2018-05-28T04:01:37Z

‎Offsets

Jgoemat: /* other operators */

2018-05-28T03:56:40Z

‎other operators

Jgoemat: /* other operators */

2018-05-28T02:38:49Z

‎other operators

Jgoemat: /* __lt */

2018-05-28T02:36:35Z

‎__lt

Jgoemat: /* __lt */

2018-05-28T02:35:33Z

‎__lt

Jgoemat: /* lt */ Added lt metamethod

2018-05-28T01:38:13Z

‎__lt: Added __lt metamethod

Jgoemat: /* Metatables */ Adding information for LUA object oriented tutorial

2018-05-28T01:32:20Z

‎Metatables: Adding information for LUA object oriented tutorial

@@ Line 46: / Line 46: @@
 print('Other Area:'..tostring(rect.calculateArea({ length = 4, width = 3 }))) -- p
 print('Other Area2:'..tostring(rect.calculateArea2({ length = 4, width = 3 })))
-print('Other Area3:'..tostring(rect.calculateArea3({ length = 4, width = 3 }
+print('Other Area3:'..tostring(rect.calculateArea3({ length = 4, width = 3 })))
 </pre>

← Older revision		Revision as of 04:01, 28 May 2018
Line 385:		Line 385:
	local a1 = Address.new('[playerptr]')		local a1 = Address.new('[playerptr]')
	print('health is at '..(a1 + 0x48))		print('health is at '..(a1 + 0x48))
		+
		+	=== Reading and Writing memory ===
		+
		+	Next I set '''__index''' and '''__newindex''' on the metatables to handle reading and
		+	writing simple types to the memory address:
		+
		+	<pre>
		+	--[[ __index method to access properties that aren't there
		+	--]]
		+	function Address:__index(key)
		+	local original = key
		+	key = key:lower()
		+	if key == 'byte' then
		+	local b = readBytes(self.address, 1)
		+	return b
		+	end
		+	if key == 'smallinteger' then return readSmallInteger(self.address) end
		+	if key == 'integer' then return readInteger(self.address) end
		+	if key == 'qword' then return readQword(self.address) end
		+	if key == 'pointer' then return readPointer(self.address) end
		+	if key == 'float' then return readFloat(self.address) end
		+	if key == 'double' then return readDouble(self.address) end
		+	if key == 'string' then return readString(self.address, MAX_STRING_LENGTH) end
		+	return getmetatable(self)[original]
		+	end
		+
		+	--[[ __newindex method to write properties that aren't there, for writing
		+	values to memory at the address
		+	--]]
		+	function Address:__newindex(key, value)
		+	local original = key
		+	key = key:lower()
		+	if key == 'byte' then return writeBytes(self.address, 1, value) end
		+	if key == 'smallinteger' then return writeSmallInteger(self.address, value) end
		+	if key == 'integer' then return writeInteger(self.address, value) end
		+	if key == 'qword' then return writeQword(self.address, value) end
		+	if key == 'pointer' then return writePointer(self.address, value) end
		+	if key == 'float' then return writeFloat(self.address, value) end
		+	if key == 'double' then return writeDouble(self.address, value) end
		+	if key == 'string' then return writeString(self.address, value) end
		+	self[key] = value
		+	return value
		+	end
		+	</pre>
		+
		+	Notice I use '''key:lower()''' so you can use any case with the property names, and you can access them like properties.
		+	For example to add 10 to the player's health you could do this:
		+
		+	local a1 = Address.new('[playerptr]')
		+	local health = a1 + 0x48 -- will be an Address
		+	health.integer = health.integer + 10
		+
		+	I also added some standard functions for arrays of bytes because they require the
		+	count as a parameter:
		+
		+	<pre>
		+
		+	--[[ Function to read a number of bytes
		+	--]]
		+	function Address:readBytes(count)
		+	return readBytes(self.address, count, true)
		+	end
		+
		+	--[[ Function to write a number of bytes
		+	--]]
		+	function Address:writeBytes(bytes)
		+	return readBytes(self.address, bytes)
		+	end
		+
		+	--[[ Function to read a number of bytes as an AOB string
		+	--]]
		+	function Address:readAOB(count)
		+	local bytes = readBytes(self.address, count, true)
		+	local strings = {}
		+	for i,b in ipairs(bytes) do
		+	table.insert(strings, string.format('%02X', b))
		+	end
		+	return table.concat(strings, ' ')
		+	end
		+	</pre>

← Older revision		Revision as of 03:56, 28 May 2018
Line 273:		Line 273:
	print('rectAdded is '..rectAdded..' and rectExpanded is '..rectExpanded)		print('rectAdded is '..rectAdded..' and rectExpanded is '..rectExpanded)
	</pre>		</pre>
		+
		+	== Address Example ==
		+
		+	Code: https://gist.github.com/JasonGoemaat/6e879ba3cd46b79a2208093541bae331
		+
		+	I've been frustrated with addresses in Cheat Engine so I created a class that helps me out.
		+	It makes it easy to handle reading memory values and adding offsets without having to remember
		+	what is a string and what is a number. You can do something like this to change
		+	the health at offset 0x48 to a pointer stored in the global symbol 'playerptr' by a script:
		+
		+	local player = Address('[playerptr]')
		+	player:offset(0x48).integer = 100
		+
		+	First we have code to create the class and allow you to create an instance with
		+	'''Address.new(value)''' or '''Address(value)''':
		+
		+	<pre>
		+	local Address = {}
		+
		+	--[[ Return either a number or null for an address. If the address is
		+	already a number, return it. If a string, do a symbol lookup.
		+	--]]
		+	local ValueToNumber = function(value)
		+	if type(value) == 'string' then value = getAddressSafe(value) end
		+	if type(value) ~= 'number' then return nil end
		+	return value
		+	end
		+
		+	--[[ Constructor to return a new Address object given a value.
		+	Usage:
		+	local address1 = Address.new('[modifiers_ptr]+80')
		+	local address2 = Address.new(0x717335200)
		+	--]]
		+	function Address.new(value)
		+	local obj = {}
		+	if type(value) == 'string' then
		+	obj.symbol = value
		+	value = getAddressSafe(value)
		+	end
		+	if type(value) ~= 'number' then return nil end
		+	obj.address = value
		+	obj.hex = string.format('%X', value)
		+	return setmetatable(obj, Address)
		+	end
		+
		+	--[[ Alternate constructor can be called just by Address()
		+	Usage:
		+	local address1 = Address('[modifiers_ptr]+80')
		+	local address2 = Address(0x717335200)
		+	--]]
		+	setmetatable(Address, { __call = function(tbl, value) return Address.new(value) end })
		+	</pre>
		+
		+	These will create an object with numeric '''address''' and string '''hex''' properties,
		+	along with '''symbol''' for the original string passed if it was created using CE's
		+	string address interpretation.
		+
		+	=== String helpers ===
		+
		+	Next we override '''___tostring''' and '''__concat''' to make debuging easier:
		+
		+	<pre>
		+	--[[ For output as a string, just output hex value
		+	--]]
		+	function Address:__tostring()
		+	return self.hex
		+	end
		+
		+	--[[ For concatenation, mostly for debug purposes use hex value
		+	--]]
		+	function Address:__concat(a)
		+	return tostring(self)..tostring(a)
		+	end
		+	</pre>
		+
		+	So you can do this:
		+
		+	local player = Address('[playerptr]')
		+	print('player is address '..player)
		+	-- output something like 'player is address 74821030'
		+
		+	=== Offsets ===
		+
		+	Next I create an '''offset''' function and override '''__add''' to do the same thing. These
		+	work with strings (converted to Address instances), Addresse instances, or just numbers.
		+
		+	<pre>
		+	--[[ Add an offset (number, Address, or string evaluated by CE) to the address
		+	and return a new instance.
		+	--]]
		+	function Address:offset(value)
		+	if type(value) == 'string' then value = Address(value) end
		+	if type(value) == 'table' and value.address ~= nil then value = value.address end
		+	if type(value) ~= 'number' then return nil end
		+	return Address(self.address + value)
		+	end
		+
		+	--[[ __add is an operator so you can do the following:
		+	local address = Address('modifiers_ptr')
		+	address = address + 0x1c
		+	--]]
		+	function Address:__add(value)
		+	-- handle if we are the second operand, i.e. '0x18 + address'
		+	if getmetatable(value) == Address then return value:offset(self) end
		+	return self:offset(value)
		+	end
		+	</pre>
		+
		+	Sample usage:
		+
		+	local a1 = Address.new('[playerptr]')
		+	print('health is at '..(a1 + 0x48))

@@ Line 221: / Line 221: @@
 === other operators ===
-* ``__add`` - Changes the behavior of the '+' operator, i.e. 'rect1 + rect2'
+* '''__add''' - Changes the behavior of the '+' operator, i.e. 'rect1 + rect2'
-* ``__sub`` - Changes the behavior of the '-' operator, i.e. 'rect1 - rect2'
+* '''__sub''' - Changes the behavior of the '-' operator, i.e. 'rect1 - rect2'
-* ``__mul`` - Changes the behavior of the '*' operator, i.e. 'rect1 * rect2'
+* '''__mul''' - Changes the behavior of the '*' operator, i.e. 'rect1 * rect2'
-* ``__div`` - Changes the behavior of the '/' operator, i.e. 'rect1 / rect2'
+* '''__div''' - Changes the behavior of the '/' operator, i.e. 'rect1 / rect2'
-* ``__mod`` - Changes the behavior of the '%' operator, i.e. 'rect1 % rect2'
+* '''__mod''' - Changes the behavior of the '%' operator, i.e. 'rect1 % rect2'
-* ``__unm`` - Changes the behavior of the unary minus '-' operator, i.e. '-rect2'
+* '''__unm''' - Changes the behavior of the unary minus '-' operator, i.e. '-rect2'
-* ``__le`` - Changes the behavior of the '<=' operator (and '>=' by reversing args)
+* '''__le''' - Changes the behavior of the '<=' operator (and '>=' by reversing args)
-* ``__concat`` - Changes the behavior of the '..' operator, i.e. 'rect1..rect2' or 'rect1..string'
+* '''__concat''' - Changes the behavior of the '..' operator, i.e. 'rect1..rect2' or 'rect1..string'
-* ``__eq`` - Changes the behavior of the '==' operator (and '~='), i.e. 'rect1 == rect2'
+* '''__eq''' - Changes the behavior of the '==' operator (and '~='), i.e. 'rect1 == rect2'
-* ``__tostring` - Not an operator, but can change the results when using print() or tostring(), i.e. 'print(rect1)'
+* '''__tostring''' - Not an operator, but can change the results when using print() or tostring(), i.e. 'print(rect1)'
-For example you may want to override ``__add`` and return a new Rectangle object with the length and width of
+For example you may want to override '''__add''' and return a new Rectangle object with the length and width of
 two rectangles added together, or to expand both the length and width when you add a number to it.
-You may want to override `__tostring` and the concat operator `..` so that you can easily print out your
+You may want to override '''__tostring''' and the concat operator '''..''' so that you can easily print out your
 objects:

@@ Line 186: / Line 186: @@
 === __lt ===
-``__lt`` is a function used for less than comparison, and for greater than comparison by
+'''__lt''' is a function used for less than comparison, and for greater than comparison by
 reversing the arguments.  It is really useful for sorting arrays.  Here we sort the
 rectangles array based on their area:

@@ Line 182: / Line 182: @@
 print('rect1: '..tostring(rect1:calculateArea()))
 print('rect2: '..tostring(rect2:calculateArea()))
 </pre>

@@ Line 77: / Line 77: @@
 Here are some useful links for reference:
-* [[http://lua-users.org/wiki/MetamethodsTutorial|MetamethodsTutorial]]
+* [http://lua-users.org/wiki/MetamethodsTutorial MetamethodsTutorial]
-* [[http://nova-fusion.com/2011/06/30/lua-metatables-tutorial/|metatables tutorial]]
+* [http://nova-fusion.com/2011/06/30/lua-metatables-tutorial/ metatables tutorial]

Tutorials:Lua:ObjectOriented - Revision history

Ajanuw: /* Calling Notation */

Dark Byte: Reverted edits by This content is not available (Talk) to last revision by Jgoemat

This content is not available: Replaced content with 'Sorry! Content not available.'

Jgoemat: /* Offsets */

Jgoemat: /* other operators */

Jgoemat: /* other operators */

Jgoemat: /* __lt */

Jgoemat: /* __lt */

Jgoemat: /* __lt */ Added __lt metamethod

Jgoemat: /* Metatables */ Adding information for LUA object oriented tutorial

Jgoemat: /* lt */ Added lt metamethod