# sapdbUnpack.py

import sys
import string
import re
import os

def outfileName (options, fname):
    if options.outfile:
        return options.outfile
    base = os.path.basename (fname)
    if base [-1] == 'c':
        result = base + '.c'
    elif base [-1] == 'a':
        if os.name == 'unix':
            result = base + '.s'
        else:
            result = base + '.asm'
    else:
        result = base + '.pas'
    return os.path.join (options.outdir, result)

startBlock = '\n' + r'\s*%s\s*:'
endBlock = '[.]CM [*]-END-[*] %s -------'
defineStartRE = re.compile (startBlock % 'define', re.I)
defineEndRE = re.compile (endBlock % 'define', re.I)
codeStartRE = re.compile (startBlock % 'code', re.I)
codeEndRE = re.compile (endBlock % 'code', re.I)

def extractBlock (source, startRE, endRE):
    match = startRE.search (source)
    if not match:
        return ''
    blockStart = match.end ()
    match = endRE.search (source, blockStart)
    assert match
    blockEnd = match.start ()
    return source [blockStart:blockEnd]

def sapdbUnpack (options, fname):
    outfile = outfileName (options, fname)
    data = open (fname, 'rt').read ()
    definition = extractBlock (data, defineStartRE, defineEndRE)
    code = extractBlock (data, codeStartRE, codeEndRE)
    print fname, '=>', outfile
    open (outfile, 'wt').write (definition + code)

def patchOptions (options):
    if os.path.isdir (options.output):
        options.outdir = options.output
        options.outfile = None
    else:
        options.outdir = '.'
        options.outfile = options.output

def main (options, args):
    """extract source from module frame

    Unless specified with -o, the name of the output file
    is given the proper extension
    """
    patchOptions (options)
    rc = 0
    for arg in args:
        if not os.path.exists (arg):
            sys.stderr.write (arg + ' does not exist\n')
            rc = 1
            continue
        ext = os.path.splitext (arg) [1]
        if ext:
            sys.stderr.write (arg + ' skipped\n')
            continue
        sapdbUnpack (options, arg)
    sys.exit (rc)


def _options ():
    return [
        # (optstring, varname, typechar, default, help)
        ('o', 'output', ':', '.', 'output file or output dir'),
        ]

if __name__ == '__main__':
    import optlib
    optlib.optMain2 (main, _options ())