lazy_read.coffee

fs = require('fs')

TYPES = 
	Int8:
		SIZE: 1, U: 1
	Int16:
		E: 1, SIZE: 2, U: 1
	Int32:
		E: 1, SIZE: 4, U: 1
	Float:
		E: 1, SIZE: 4
	Double:
		E: 1, SIZE: 8

_TYPES = {}

for key, type of TYPES
		_types = if type.E then [key + 'LE', key + 'BE'] else [key]

		_types.push('U' + _type) for _type in _types if type.U

		for k in _types
			_TYPES[k] = type.SIZE 

class Reader
	reader: (func, size) -> -> func.call(@buffer, @offset.read, @offset.read += size)

	constructor: (@buffer = new Buffer(4096), @offset = {read: 0, write: 0}, @data = {}) ->
		@['read' + type] = @reader(Buffer.prototype['read' + type], size) for type, size of _TYPES

	readLEM128: ->
		if(@readUInt8() == 11)
			len = @readUInt8()
			return @buffer.toString('utf8', @offset.read, @offset.read += len) 

db = fs.readFileSync('collection.db')

re = new Reader(db)

data = 
	version: re.readUInt32LE()
	amount: re.readUInt32LE()
	collections: []


for c in [0 ... data.amount]
	collection =  
		name: re.readLEM128()
		count: re.readUInt32LE()
		maps: []

	collection.maps.push(re.readLEM128()) for b in [0 ... collection.count]

	data.collections.push(collection)

console.log(JSON.stringify(data, null, '   '))