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bit
Types for this namespace are provided by the lua-types dependency and are not generated by @defold-typescript/types.
Lua BitOp is a C extension module for Lua 5.1/5.2 which adds bitwise operations on numbers.
Lua BitOp is Copyright © 2008-2012 Mike Pall. Lua BitOp is free software, released under the MIT license (same license as the Lua core).
Lua BitOp is compatible with the built-in bitwise operations in LuaJIT 2.0 and is used on platforms where Defold runs without LuaJIT.
For clarity the examples assume the definition of a helper function printx().
This prints its argument as an unsigned 32 bit hexadecimal number on all platforms:
function printx(x)
print("0x"..bit.tohex(x))
endFunctions
bit.tobit(x: number): numberbit.tohex(x: number, n?: number): stringbit.bnot(x: number): numberbit.bor(x: number, ...rest: number[]): numberbit.band(x: number, ...rest: number[]): numberbit.bxor(x: number, ...rest: number[]): numberbit.lshift(x: number, n: number): numberbit.rshift(x: number, n: number): numberbit.arshift(x: number, n: number): numberbit.rol(x: number, n: number): numberbit.ror(x: number, n: number): numberbit.bswap(x: number): number
bit.tobit(x: number): number
Normalizes a number to the numeric range for bit operations and returns it. This function is usually not needed since all bit operations already normalize all of their input arguments.
print(0xffffffff) --> 4294967295 (*)
print(bit.tobit(0xffffffff)) --> -1
printx(bit.tobit(0xffffffff)) --> 0xffffffff
print(bit.tobit(0xffffffff + 1)) --> 0
print(bit.tobit(2^40 + 1234)) --> 1234(*) See the treatment of hex literals for an explanation why the printed numbers in the first two lines differ (if your Lua installation uses a double number type).
Parameters
x:number— number to normalize
Returns
y:number— normalized number
bit.tohex(x: number, n?: number): string
Converts its first argument to a hex string. The number of hex digits is given by the absolute value of the optional second argument. Positive numbers between 1 and 8 generate lowercase hex digits. Negative numbers generate uppercase hex digits. Only the least-significant 4*|n| bits are used. The default is to generate 8 lowercase hex digits.
print(bit.tohex(1)) --> 00000001
print(bit.tohex(-1)) --> ffffffff
print(bit.tohex(0xffffffff)) --> ffffffff
print(bit.tohex(-1, -8)) --> FFFFFFFF
print(bit.tohex(0x21, 4)) --> 0021
print(bit.tohex(0x87654321, 4)) --> 4321Parameters
x:number— number to convertn:number— number of hex digits to return
Returns
s:string— hexadecimal string
bit.bnot(x: number): number
Returns the bitwise not of its argument.
print(bit.bnot(0)) --> -1
printx(bit.bnot(0)) --> 0xffffffff
print(bit.bnot(-1)) --> 0
print(bit.bnot(0xffffffff)) --> 0
printx(bit.bnot(0x12345678)) --> 0xedcba987Parameters
x:number— number
Returns
y:number— bitwise not of number x
bit.bor(x: number, ...rest: number[]): number
Returns the bitwise or of all of its arguments. Note that more than two arguments are allowed.
print(bit.bor(1, 2, 4, 8)) --> 15Parameters
x1:number— numberx2...?:number— number(s)
Returns
y:number— bitwise or of the provided arguments
bit.band(x: number, ...rest: number[]): number
Returns the bitwise and of all of its arguments. Note that more than two arguments are allowed.
printx(bit.band(0x12345678, 0xff)) --> 0x00000078Parameters
x1:number— numberx2...?:number— number(s)
Returns
y:number— bitwise and of the provided arguments
bit.bxor(x: number, ...rest: number[]): number
Returns the bitwise xor of all of its arguments. Note that more than two arguments are allowed.
printx(bit.bxor(0xa5a5f0f0, 0xaa55ff00)) --> 0x0ff00ff0Parameters
x1:number— numberx2...?:number— number(s)
Returns
y:number— bitwise xor of the provided arguments
bit.lshift(x: number, n: number): number
Returns the bitwise logical left-shift of its first argument by the number of bits given by the second argument. Logical shifts treat the first argument as an unsigned number and shift in 0-bits. Only the lower 5 bits of the shift count are used (reduces to the range [0..31]).
print(bit.lshift(1, 0)) --> 1
print(bit.lshift(1, 8)) --> 256
print(bit.lshift(1, 40)) --> 256
printx(bit.lshift(0x87654321, 12)) --> 0x54321000Parameters
x:number— numbern:number— number of bits
Returns
y:number— bitwise logical left-shifted number
bit.rshift(x: number, n: number): number
Returns the bitwise logical right-shift of its first argument by the number of bits given by the second argument. Logical shifts treat the first argument as an unsigned number and shift in 0-bits. Only the lower 5 bits of the shift count are used (reduces to the range [0..31]).
print(bit.rshift(256, 8)) --> 1
print(bit.rshift(-256, 8)) --> 16777215
printx(bit.rshift(0x87654321, 12)) --> 0x00087654Parameters
x:number— numbern:number— number of bits
Returns
y:number— bitwise logical right-shifted number
bit.arshift(x: number, n: number): number
Returns the bitwise arithmetic right-shift of its first argument by the number of bits given by the second argument. Arithmetic right-shift treats the most-significant bit as a sign bit and replicates it. Only the lower 5 bits of the shift count are used (reduces to the range [0..31]).
print(bit.arshift(256, 8)) --> 1
print(bit.arshift(-256, 8)) --> -1
printx(bit.arshift(0x87654321, 12)) --> 0xfff87654Parameters
x:number— numbern:number— number of bits
Returns
y:number— bitwise arithmetic right-shifted number
bit.rol(x: number, n: number): number
Returns the bitwise left rotation of its first argument by the number of bits given by the second argument. Bits shifted out on one side are shifted back in on the other side. Only the lower 5 bits of the rotate count are used (reduces to the range [0..31]).
printx(bit.rol(0x12345678, 12)) --> 0x45678123Parameters
x:number— numbern:number— number of bits
Returns
y:number— bitwise left-rotated number
bit.ror(x: number, n: number): number
Returns the bitwise right rotation of its first argument by the number of bits given by the second argument. Bits shifted out on one side are shifted back in on the other side. Only the lower 5 bits of the rotate count are used (reduces to the range [0..31]).
printx(bit.ror(0x12345678, 12)) --> 0x67812345Parameters
x:number— numbern:number— number of bits
Returns
y:number— bitwise right-rotated number
bit.bswap(x: number): number
Swaps the bytes of its argument and returns it. This can be used to convert little-endian 32 bit numbers to big-endian 32 bit numbers or vice versa.
printx(bit.bswap(0x12345678)) --> 0x78563412
printx(bit.bswap(0x78563412)) --> 0x12345678Parameters
x:number— number
Returns
y:number— bitwise swapped number