Bits🔗ℹ

package: bits

1 Overview🔗ℹ

This library provides utilities for treating Racket byte string as a bit matrix with a width of 8, allowing for direct, two-dimensional access or modification of individual bits.

2 Bit Type🔗ℹ

type
Bit

A type representing a single bit, defined as (∪ Zero One).

procedure
(bit? v) → Boolean
v : Any

Returns #t if v is 0 or 1, #f otherwise.

Example:

> (:print-type bit?)
(-> Any Boolean : Bit)

procedure
(one? v) → Boolean
v : Any

Returns #t if v is 1, #f otherwise.

Example:

> (:print-type one?)
(-> Any Boolean : One)

3 Bit Matrix Operations🔗ℹ

procedure
(bits-ref bs i j) → Bit
  bs : Bytes
  i : Integer
  j : Integer

Gets the bit at row i and column j from bs.

Examples:

> (define bs #"U")
> (bits-ref bs 0 0)
- : Integer [more precisely: Bit]
1
> (bits-ref bs 0 1)
- : Integer [more precisely: Bit]
0

procedure
(bits-set! bs i j bit) → Void
  bs : Bytes
  i : Integer
  j : Integer
  bit : Bit

Sets the bit at row i and column j in bs to bit.

Examples:

> (define bs (bytes 0))
> (bits-set! bs 0 7 1)
> bs
- : Bytes
#"\200"
> (bits-set! bs 0 7 0)
> bs
- : Bytes
#"\0"

4 Type Conversions🔗ℹ

procedure
(bit->boolean bit) → Boolean
bit : Bit

Convert a bit to a boolean.

procedure
(boolean->bit bool) → Bit
bool : Boolean

Convert a boolean to a bit.