charleslxh / buffer-iterator

buffer iterator, to read byte one by one

Buffer Iterator

Let Buffer iterable.

Install

$ npm install buffer-iterator --save

Static Methods

1. from(): BufferIterator: Create a BufferIterator, arguments is Buffer.from's arguments.

   const bi = BufferIterator.from([0x01, 0x02]);
   // same as 
   const bi = new BufferIterator(Buffer.from([0x01, 0x02]));

Instance Methods

1. next(needMovePointer = true): Number|Null: Read a byte from buffer, and move pointer to the next byte when needMovePointer is true(default), if it has not next byte, return null.

   const assert = require('assert');
   const BufferIterator = require('buffer-iterator');
   
   const bi = BufferIterator.from([0x01, 0x02]);
   assert.equal(bi.next(), 0x01);

2. prev(needMovePointer = false): Number|Null: Read a previous byte from buffer, and move pointer to previous byte when needMovePointer is true(default false). Returns previous byte if it exists, otherwise it returns null.

   const assert = require('assert');
   const BufferIterator = require('buffer-iterator');
   
   const bi = BufferIterator.from([0x01, 0x02]);
   bi.next();
   bi.next();
   assert.equal(bi.prev(), 0x01);

3. current(): Number: Returns current byte if it exists, otherwise it returns null.

   const assert = require('assert');
   const BufferIterator = require('buffer-iterator');
   
   const bi = BufferIterator.from([0x01, 0x02]);
   bi.next();
   assert.equal(bi.current(), 0x01);

4. hasNext(): Boolean: Returns true if and only if the iterator has other bytes to read.

   const assert = require('assert');
   const BufferIterator = require('buffer-iterator');
   
   const bi = BufferIterator.from([0x01, 0x02]);
   bi.next();
   assert.equal(bi.hasNext(), true);

5. remainLength(): Number: Counts bytes which have not been read yet.

   const assert = require('assert');
   const BufferIterator = require('buffer-iterator');
   
   const bi = BufferIterator.from([0x01, 0x02]);
   bi.next();
   assert.equal(bi.remainLength(), 1);

6. readBytes(number = 1): Buffer|Null: Read multi bytes.

   const assert = require('assert');
   const BufferIterator = require('buffer-iterator');
   
   const bi = BufferIterator.from([0x01, 0x02]);
   assert.equal(bi.readBytes(10).equals(Buffer.from([0x01, 0x02])), true);

7. append(buf): Null: Append buffer.

   const assert = require('assert');
   const BufferIterator = require('buffer-iterator');
   
   const bi = BufferIterator.from([0x01, 0x02]);
   bi.append(Buffer.from([0x03]));
   assert.equal(bi.buffer.equals(Buffer.from([0x01, 0x02, 0x03])), true);

8. use for...of.

   const assert = require('assert');
   const BufferIterator = require('buffer-iterator');
   
   const bi = BufferIterator.from([0x01, 0x02]);
   for (let byte of bi) {
     console.log(byte);
   }
   
   // 1
   // 2

Contribute

1. fork.

2. install dependencies.

   $ npm install

3. run command.

   $ gulp