Copyright | (c) The University of Glasgow 2001 |
---|---|

License | BSD-style (see the file libraries/base/LICENSE) |

Maintainer | libraries@haskell.org |

Stability | experimental |

Portability | portable |

Safe Haskell | Safe |

Language | Haskell2010 |

Unsigned integer types.

- data Word :: *
- data Word8
- data Word16
- data Word32
- data Word64
- byteSwap16 :: Word16 -> Word16
- byteSwap32 :: Word32 -> Word32
- byteSwap64 :: Word64 -> Word64

# Unsigned integral types

data Word :: *

8-bit unsigned integer type

16-bit unsigned integer type

32-bit unsigned integer type

64-bit unsigned integer type

# byte swapping

byteSwap16 :: Word16 -> Word16 Source

Swap bytes in `Word16`

.

*Since: 4.7.0.0*

byteSwap32 :: Word32 -> Word32 Source

Reverse order of bytes in `Word32`

.

*Since: 4.7.0.0*

byteSwap64 :: Word64 -> Word64 Source

Reverse order of bytes in `Word64`

.

*Since: 4.7.0.0*

# Notes

- All arithmetic is performed modulo 2^n, where n is the number of
bits in the type. One non-obvious consequence of this is that
`negate`

should*not*raise an error on negative arguments. - For coercing between any two integer types, use
`fromIntegral`

, which is specialized for all the common cases so should be fast enough. Coercing word types to and from integer types preserves representation, not sign. - It would be very natural to add a type
`Natural`

providing an unbounded size unsigned integer, just as`Integer`

provides unbounded size signed integers. We do not do that yet since there is no demand for it. - The rules that hold for
`Enum`

instances over a bounded type such as`Int`

(see the section of the Haskell report dealing with arithmetic sequences) also hold for the`Enum`

instances over the various`Word`

types defined here. - Right and left shifts by amounts greater than or equal to the width
of the type result in a zero result. This is contrary to the
behaviour in C, which is undefined; a common interpretation is to
truncate the shift count to the width of the type, for example
`1 << 32 == 1`

in some C implementations.