Super simple standalone script to parse a bmap file (works on Python2 or Python3)

bmap_write.py

#!/usr/bin/python

# A super-simple standalone script (which makes various assumptions, and does no
# verification) to show how easily .bmap files can be parsed.
# It only supports uncompressed images, and if the image is named mydata.img it
# assumes the bmap is named mydata.bmap

# MIT License
#
# Copyright (c) 2018 Andrew Scheller
#
# Permission is hereby granted, free of charge, to any person obtaining a copy
# of this software and associated documentation files (the "Software"), to deal
# in the Software without restriction, including without limitation the rights
# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
# copies of the Software, and to permit persons to whom the Software is
# furnished to do so, subject to the following conditions:
#
# The above copyright notice and this permission notice shall be included in all
# copies or substantial portions of the Software.
#
# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
# SOFTWARE.

import sys
import xml.etree.ElementTree as ET
import re
import os

if len(sys.argv) != 3:
    print("Usage: %s <raw-file> <output-file>" % os.path.basename(sys.argv[0]))
    sys.exit(1)
raw_file = sys.argv[1]
output_file = sys.argv[2]
if not os.path.isfile(raw_file):
    print("raw-file '%s' doesn't exist" % raw_file)
    sys.exit(1)
file_root, file_ext = os.path.splitext(raw_file)
bmap_file = file_root + '.bmap'
if not os.path.isfile(bmap_file):
    print("bmap-file '%s' doesn't exist" % bmap_file)
    sys.exit(1)

bmap_root = ET.parse(bmap_file).getroot()
blocksize = int(bmap_root.find('BlockSize').text)
with open(raw_file, 'rb') as filedata:
    with open(output_file, 'wb') as outdata:
        try:
            outdata.truncate(int(bmap_root.find('ImageSize').text))
        except:
            pass
        for bmap_range in bmap_root.find('BlockMap').findall('Range'):
            blockrange = bmap_range.text
            m = re.match('^\s*(\d+)\s*-\s*(\d+)\s*$', blockrange)
            if m:
                start = int(m.group(1))
                end = int(m.group(2))
            else:
                start = int(blockrange)
                end = start
            start_offset = start * blocksize
            filedata.seek(start_offset, 0)
            outdata.seek(start_offset, 0)
            for i in range(end - start + 1):
                outdata.write(filedata.read(blocksize))
        outdata.flush()
        os.fsync(outdata.fileno())