a simple MCR chunk extractor

mcrtool.py

#!/usr/bin/python

usage = "python contrib/%prog [-v] [-f file] [-o output/]"

description = """
Extracts the given MCR file into output/. If -o is not provided, it
will be derived from the input file name.
"""

from optparse import OptionParser
import sys
import os.path

# sys.path wrangling, so we can access Overviewer code
overviewer_dir = os.path.split(os.path.split(os.path.abspath(__file__))[0])[0]
sys.path.insert(0, overviewer_dir)

import c_overviewer
import nbt
from world import base36encode

def main():
    parser = OptionParser(usage=usage, description=description)
    parser.add_option("-v", "--verbose", dest="verbose", action="store_true",
                      help="list every file extracted.")
    parser.add_option("-f", "--file", dest="file", default=None, metavar="FILE",
                      help="the MCR file to extract")
    parser.add_option("-o", "--output", dest="output", default=None, metavar="OUT",
                      help="the output directory")
    
    opt, args = parser.parse_args()
    
    if not len(args) == 0:
        parser.print_help()
        sys.exit(1)
        
    if opt.file is None: # and opt.output is None:
        parser.print_help()
        print >>sys.stderr, "you must provide -f"
        sys.exit(1)
    
    filename = opt.file
    if filename:
        if not filename.lower().endswith('.mcr'):
            print >>sys.stderr, "error: not a MCR file"
            sys.exit(1)
        if not os.path.exists(filename):
            print >>sys.stderr, "error: cannot open '%s'" % (filename,)
            sys.exit(1)
    
    outdir = opt.output
    if outdir is None:
        assert filename
        outdir = os.path.splitext(filename)[0]
        outdir = os.path.split(outdir)[1]
    
    if not (os.path.exists(outdir) and os.path.isdir(outdir)):
        try:
            os.makedirs(outdir)
        except:
            print >>sys.stderr, "error: cannot create directory '%s'" % (outdir,)
            sys.exit(1)
    
    ## start extraction
    
    mcr = nbt.MCRFileReader(filename)
    for x, y in mcr.get_chunks():
        chunk = mcr.load_chunk(x, y)
        
        outfile = "chunk.%s.%s.nbt" % (base36encode(x), base36encode(y))
        outfile = os.path.join(outdir, outfile)
        
        if opt.verbose:
            print outfile
        
        fout = open(outfile, 'wb')
        fout.write(chunk._file.read())
        fout.close()

if __name__ == "__main__":
    main()