#!/usr/bin/env python3

from modules.logger import logger
import struct

# Declare a class that can automatically convert virtual executable addresses
# to file addresses
class Bin:
  file = None

  def __init__(self, filename):
    logger.debug('Parsing headers of "%s"... ', filename)
    self.file = open(filename, 'rb')

    #HACK: Strictly, we should be parsing the header, but we know where
    #      everything is in these two files so we just jump straight there

    # Read ImageBase
    self.file.seek(0xB4)
    self.imagebase, = struct.unpack('<i', self.file.read(4))

    # Read .text VirtualAddress
    self.file.seek(0x184)
    self.textvirt, = struct.unpack('<i', self.file.read(4))

    # Read .text PointerToRawData
    self.file.seek(0x18C)
    self.textraw, = struct.unpack('<i', self.file.read(4))
    logger.debug('... Parsing finished')

  def __del__(self):
    if self.file:
      self.file.close()

  def get_addr(self, virt):
    return virt - self.imagebase - self.textvirt + self.textraw

  def read(self, offset, size):
    self.file.seek(self.get_addr(offset))
    return self.file.read(size)