binary_reader.py

#!/usr/bin/env python
# -*- coding: utf-8 -*-

import struct

class BinaryReader:
    # based: http://code.activestate.com/recipes/577610-decoding-binary-files/
    # http://www.python.jp/doc/nightly/library/struct.html

    _TYPES = {
        'int8' : struct.Struct('<b'),
        'uint8' : struct.Struct('<B'),
        'int16' : struct.Struct('<h'),
        'uint16' : struct.Struct('<H'),
        'int32' : struct.Struct('<i'),
        'uint32' : struct.Struct('<I'),
        'int64' : struct.Struct('<q'),
        'uint64' : struct.Struct('<Q'),
        'float' : struct.Struct('<f'),
        'float32' : struct.Struct('<f'),
        'single' : struct.Struct('<f'),
        'float64' : struct.Struct('<d'),
        'double' : struct.Struct('<d'),
        'char' : struct.Struct('<c'),
        'char[]' : struct.Struct('<s'),
        'pad' : struct.Struct('<x'),
        'bool' : struct.Struct('<?'),
    }

    _FORMATS = {
        'int8' : 'b',
        'uint8' : 'B',
        'int16' : 'h',
        'uint16' : 'H',
        'int32' : 'i',
        'uint32' : 'I',
        'int64' : 'q',
        'uint64' : 'Q',
        'float' : 'f',
        'float32' : 'f',
        'single' : 'f',
        'float64' : 'd',
        'double' : 'd',
        'char' : 'c',
        'char[]' : 's',
        'pad' : 'x',
        'bool' : '?',
    }

    def __init__(self, fp):
        self.stream = fp.read()
        self.index = 0

    def read(self,type, next=False):
        t = self._TYPES[type]
        value = t.unpack_from(self.stream,self.index)[0]
        self.index += t.size
        if next:
            self.next(t.size)
        return value

    def reads(self,type, next=False):
        # return multiple-values
        t = self._TYPES[type]
        values = t.unpack_from(self.stream,self.index)
        self.index += t.size
        if next:
            self.next(t.size)
        return values

    def next(self, count):
        return self.stream[self.index:self.index+count]