# Crate bit_reverse [−] [src]

## Library Objective

This library provides a number of ways to compute the bit reversal of all primitive integers. There are currently 3 different algorithms implemented: Bitwise, Parallel, and Lookup reversal.

## Example

use bit_reverse::ParallelReverse; assert_eq!(0xA0u8.swap_bits(), 0x05u8);Run

This library is very simple to uses just import the crate and the algorithm you want to use. Then you can call swap_bits() on any primitive integer. If you want to try a different algorithm just change the use statement and now your program will use the algorithm instead.

## YMMV Performance Comparison

I wouldn't use BitwiseReverse as it is mainly there for completeness and is strictly inferior to ParallelReverse, which is a Bitwise Parallel Reverse and thus an order of magnitude faster. I would recommend you use the ParallelReverse as it performs equal to or better than LookupReverse for all types. Plus as an added bonus doesn't eat your cache with a lookup table.

## Memory Consumption

Bitwise uses the least amount of memory only using three integers to compute the reversal. Parallel allocates 3 constants of the same size of the type being reversed. Lookup allocates 256 u8s or 256 bytes to do its byte lookup reversal.

## no_std Compatible

To link to core instead of STD, disable default features for this library in your Cargo.toml. Cargo choosing features

## Traits

BitwiseReverse |
Computes bit reversal by going bit by bit and setting the reverse position bit for the output. |

LookupReverse |
Computes bit reversal by using lookup table to translate a single byte into its reverse. For multi-byte types, the byte order is swapped to complete the reversal. |

ParallelReverse |
Computes bit reversal by using a divide and conquer approach. Pairs of bits are swapped. Then neighboring bit pairs are swapped. Each time swapping the next largest group of bits. This is done until the entire data has been bit reversed. |