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A simple way to traverse a nodejs Buffer while keeping track of position

branch: master
README.md

BufferCursor

This is a simple module that allows you to traverse a Buffer iteratively. You can read and write different types and the cursor's position will update with the proper size, which you can see through .tell() you can also .seek()

var bc = new BufferCursor(buffer);
bc.readUInt16BE();
bc.readUInt8();
bc.readUInt32BE();
console.log(bc.tell());

Will output 7

Methods

For the most part BufferCursor and Buffer share the same methods, there's just a slight alteration in method signature, none of the methods take an offset.

So .readUInt16LE(10) in Buffer is equivalent to bs.seek(10); bs.readUInt16LE();

All read[U]Int and write[U]Int methods are reproduced, as are toString, write, fill, and slice. All of these methods will move the cursor through the stream and do not take an offset parameter, where an end parameter would normaly be used, here you supply a length.

The following are additional methods:

  • seek(value) -- Seek to an arbitrary position in the stream
  • tell() -- Return the current location in the stream
  • eof() -- Return true if at the end of the stream
  • toByteArray([method]) -- This is a special helper method which will return the entire stream (i.e. from the start) as an array of numbers.
    • By default it will use readUInt8 but you can pass in any read[U]Int[8,16,32][LE,BE] to change what the array is made of

Properties

  • .buffer -- Access to the raw buffer
  • .length -- The size of the buffer
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