circular-buffer

NodeJS Circular Buffer

This is a simple circular buffer implementation for NodeJS.

Usage

Below is a sample session with a circular buffer with this package. It should answer most questions.

var CircularBuffer = require("circular-buffer");

var buf = new CircularBuffer(3);
console.log(buf.capacity()); // -> 3
buf.enq(1);
buf.enq(2);
console.log(buf.size()); // -> 2
buf.enq(3);
buf.enq(4);
console.log(buf.size()); // -> 3  (despite having added a fourth item!)
buf.get(0); // -> 4  (last added item is at start of buffer)
buf.get(0,2); // -> [4,3,2]  (2-parameter get takes start and end)
buf.toarray(); // -> [4,3,2]  (equivalent to buf.get(0,buf.size() - 1) )
console.log(buf.deq()); // -> 4
buf.toarray(); // -> [3,2]
buf.deq(); // -> 3
buf.deq(); // -> 2
buf.toarray(); // -> []
buf.deq(); // -> throws RangeError("CircularBuffer dequeue on empty buffer")

Functions

• size() -> integer
  • Returns the current number of items in the buffer.
• capacity() -> integer
  • Returns the maximum number of items in the buffer (specified when creating it).
• enq(value)
  • Enqueue value at the start of the buffer
• deq() -> value
  • Dequeue an item from the start of the buffer; returns that item. Throws RangeError when the buffer is empty on invocation.
• get(idx) -> value
  • Get the value at index idx. 0 is the start of the buffer (last-enqueued item), buf.size()-1 is the oldest item in the buffer.
• get(start,end) -> [value]
  • Gets the values from index start up to and including index end; returns an array. The newest item is first in the array, and it is the same as buf.get(start).
• toarray() -> [value]
  • Equivalent to buf.get(0,buf.size() - 1): exports all items in the buffer in order.

Testing

To test the package simply run npm update && npm test in the package's root folder.