Bit-Masking Ring Buffer

A fast ring buffer implementation with cheap and safe indexing written in Rust. It works by bit-masking an integer index to get the corresponding index in an array/vec whose length is a power of 2. This is best used when indexing the buffer with an isize value. Copies/reads with slices are implemented with memcpy. This is most useful for high performance algorithms such as audio DSP.

This crate has no consumer/producer logic, and is meant to be used as a raw data structure or a base for other data structures.

Example

use bit_mask_ring_buf::{BMRingBuf, BMRingBufRef};

// Create a ring buffer with type u32. The data will be
// initialized with the default value (0 in this case).
// The actual capacity will be set to the next highest
// power of 2 if the given capacity is not already
// a power of 2.
let mut rb = BMRingBuf::<u32>::from_capacity(3);
assert_eq!(rb.capacity(), 4);

// Read/write to buffer by indexing
rb[0] = 0;
rb[1] = 1;
rb[2] = 2;
rb[3] = 3;

// Cheaply wrap when reading/writing outside of bounds
assert_eq!(rb[-1], 3);
assert_eq!(rb[10], 2);

// Memcpy into slices at arbitrary points and length
let mut read_buffer = [0u32; 7];
rb.read_into(&mut read_buffer, 2);
assert_eq!(read_buffer, [2, 3, 0, 1, 2, 3, 0]);

// Memcpy data from a slice into the ring buffer. Only
// the latest data will be copied.
rb.write_latest(&[0, 2, 3, 4, 1], 0);
assert_eq!(rb[0], 1);
assert_eq!(rb[1], 2);
assert_eq!(rb[2], 3);
assert_eq!(rb[3], 4);

// Read/write by retrieving slices directly
let (s1, s2) = rb.as_slices_len(1, 4);
assert_eq!(s1, &[2, 3, 4]);
assert_eq!(s2, &[1]);

// Aligned/stack data may also be used
let mut stack_data = [0u32, 1, 2, 3];
let mut rb_ref = BMRingBufRef::new(&mut stack_data);
rb_ref[-4] = 5;
assert_eq!(rb_ref[0], 5);
assert_eq!(rb_ref[1], 1);
assert_eq!(rb_ref[2], 2);
assert_eq!(rb_ref[3], 3);