"""Macintosh binhex compression/decompression.

easy interface:

binhex(inputfilename, outputfilename)

hexbin(inputfilename, outputfilename)

"""

#

# Jack Jansen, CWI, August 1995.

#

# The module is supposed to be as compatible as possible. Especially the

# easy interface should work "as expected" on any platform.

# XXXX Note: currently, textfiles appear in mac-form on all platforms.

# We seem to lack a simple character-translate in python.

# (we should probably use ISO-Latin-1 on all but the mac platform).

# XXXX The simple routines are too simple: they expect to hold the complete

# files in-core. Should be fixed.

# XXXX It would be nice to handle AppleDouble format on unix

# (for servers serving macs).

# XXXX I don't understand what happens when you get 0x90 times the same byte on

# input. The resulting code (xx 90 90) would appear to be interpreted as an

# escaped *value* of 0x90. All coders I've seen appear to ignore this nicety...

#

import sys

import os

import struct

import binascii

__all__ = ["binhex","hexbin","Error"]

class Error(Exception):

    pass

# States (what have we written)

[_DID_HEADER, _DID_DATA, _DID_RSRC] = range(3)

# Various constants

REASONABLY_LARGE=32768  # Minimal amount we pass the rle-coder

LINELEN=64

RUNCHAR=chr(0x90)   # run-length introducer

#

# This code is no longer byte-order dependent

#

# Workarounds for non-mac machines.

try:

    from Carbon.File import FSSpec, FInfo

    from MacOS import openrf

    def getfileinfo(name):

        finfo = FSSpec(name).FSpGetFInfo()

        dir, file = os.path.split(name)

        # XXX Get resource/data sizes

        fp = open(name, 'rb')

        fp.seek(0, 2)

        dlen = fp.tell()

        fp = openrf(name, '*rb')

        fp.seek(0, 2)

        rlen = fp.tell()

        return file, finfo, dlen, rlen

    def openrsrc(name, *mode):

        if not mode:

            mode = '*rb'

        else:

            mode = '*' + mode[0]

        return openrf(name, mode)

except ImportError:

    #

    # Glue code for non-macintosh usage

    #

    class FInfo:

        def __init__(self):

            self.Type = '????'

            self.Creator = '????'

            self.Flags = 0

    def getfileinfo(name):

        finfo = FInfo()

        # Quick check for textfile

        fp = open(name)

        data = open(name).read(256)

        for c in data:

            if not c.isspace() and (c<' ' or ord(c) > 0x7f):

                break

        else:

            finfo.Type = 'TEXT'

        fp.seek(0, 2)

        dsize = fp.tell()

        fp.close()

        dir, file = os.path.split(name)

        file = file.replace(':', '-', 1)

        return file, finfo, dsize, 0

    class openrsrc:

        def __init__(self, *args):

            pass

        def read(self, *args):

            return ''

        def write(self, *args):

            pass

        def close(self):

            pass

class _Hqxcoderengine:

    """Write data to the coder in 3-byte chunks"""

    def __init__(self, ofp):

        self.ofp = ofp

        self.data = ''

        self.hqxdata = ''

        self.linelen = LINELEN-1

    def write(self, data):

        self.data = self.data + data

        datalen = len(self.data)

        todo = (datalen//3)*3

        data = self.data[:todo]

        self.data = self.data[todo:]

        if not data:

            return

        self.hqxdata = self.hqxdata + binascii.b2a_hqx(data)

        self._flush(0)

    def _flush(self, force):

        first = 0

        while first <= len(self.hqxdata)-self.linelen:

            last = first + self.linelen

            self.ofp.write(self.hqxdata[first:last]+'\n')

            self.linelen = LINELEN

            first = last

        self.hqxdata = self.hqxdata[first:]

        if force:

            self.ofp.write(self.hqxdata + ':\n')

    def close(self):

        if self.data:

            self.hqxdata = \

                 self.hqxdata + binascii.b2a_hqx(self.data)

        self._flush(1)

        self.ofp.close()

        del self.ofp

class _Rlecoderengine:

    """Write data to the RLE-coder in suitably large chunks"""

    def __init__(self, ofp):

        self.ofp = ofp

        self.data = ''

    def write(self, data):

        self.data = self.data + data

        if len(self.data) < REASONABLY_LARGE:

            return

        rledata = binascii.rlecode_hqx(self.data)

        self.ofp.write(rledata)

        self.data = ''

    def close(self):

        if self.data:

            rledata = binascii.rlecode_hqx(self.data)

            self.ofp.write(rledata)

        self.ofp.close()

        del self.ofp

class BinHex:

    def __init__(self, (name, finfo, dlen, rlen), ofp):

        if type(ofp) == type(''):

            ofname = ofp

            ofp = open(ofname, 'w')

            if os.name == 'mac':

                fss = FSSpec(ofname)

                fss.SetCreatorType('BnHq', 'TEXT')

        ofp.write('(This file must be converted with BinHex 4.0)\n\n:')

        hqxer = _Hqxcoderengine(ofp)

        self.ofp = _Rlecoderengine(hqxer)

        self.crc = 0

        if finfo is None:

            finfo = FInfo()

        self.dlen = dlen

        self.rlen = rlen

        self._writeinfo(name, finfo)

        self.state = _DID_HEADER

    def _writeinfo(self, name, finfo):

        nl = len(name)

        if nl > 63:

            raise Error, 'Filename too long'

        d = chr(nl) + name + '\0'

        d2 = finfo.Type + finfo.Creator

        # Force all structs to be packed with big-endian

        d3 = struct.pack('>h', finfo.Flags)

        d4 = struct.pack('>ii', self.dlen, self.rlen)

        info = d + d2 + d3 + d4

        self._write(info)

        self._writecrc()

    def _write(self, data):

        self.crc = binascii.crc_hqx(data, self.crc)

        self.ofp.write(data)

    def _writecrc(self):

        # XXXX Should this be here??

        # self.crc = binascii.crc_hqx('\0\0', self.crc)

        if self.crc < 0:

            fmt = '>h'

        else:

            fmt = '>H'

        self.ofp.write(struct.pack(fmt, self.crc))

        self.crc = 0

    def write(self, data):

        if self.state != _DID_HEADER:

            raise Error, 'Writing data at the wrong time'

        self.dlen = self.dlen - len(data)

        self._write(data)

    def close_data(self):

        if self.dlen != 0:

            raise Error, 'Incorrect data size, diff=%r' % (self.rlen,)

        self._writecrc()

        self.state = _DID_DATA

    def write_rsrc(self, data):

        if self.state < _DID_DATA:

            self.close_data()

        if self.state != _DID_DATA:

            raise Error, 'Writing resource data at the wrong time'

        self.rlen = self.rlen - len(data)

        self._write(data)

    def close(self):

        if self.state < _DID_DATA:

            self.close_data()

        if self.state != _DID_DATA:

            raise Error, 'Close at the wrong time'

        if self.rlen != 0:

            raise Error, \

                  "Incorrect resource-datasize, diff=%r" % (self.rlen,)

        self._writecrc()

        self.ofp.close()

        self.state = None

        del self.ofp

def binhex(inp, out):

    """(infilename, outfilename) - Create binhex-encoded copy of a file"""

    finfo = getfileinfo(inp)

    ofp = BinHex(finfo, out)

    ifp = open(inp, 'rb')

    # XXXX Do textfile translation on non-mac systems

    while 1:

        d = ifp.read(128000)

        if not d: break

        ofp.write(d)

    ofp.close_data()

    ifp.close()

    ifp = openrsrc(inp, 'rb')

    while 1:

        d = ifp.read(128000)

        if not d: break

        ofp.write_rsrc(d)

    ofp.close()

    ifp.close()

class _Hqxdecoderengine:

    """Read data via the decoder in 4-byte chunks"""

    def __init__(self, ifp):

        self.ifp = ifp

        self.eof = 0

    def read(self, totalwtd):

        """Read at least wtd bytes (or until EOF)"""

        decdata = ''

        wtd = totalwtd

        #

        # The loop here is convoluted, since we don't really now how

        # much to decode: there may be newlines in the incoming data.

        while wtd > 0:

            if self.eof: return decdata

            wtd = ((wtd+2)//3)*4

            data = self.ifp.read(wtd)

            #

            # Next problem: there may not be a complete number of

            # bytes in what we pass to a2b. Solve by yet another

            # loop.

            #

            while 1:

                try:

                    decdatacur, self.eof = \

                            binascii.a2b_hqx(data)

                    break

                except binascii.Incomplete:

                    pass

                newdata = self.ifp.read(1)

                if not newdata:

                    raise Error, \

                          'Premature EOF on binhex file'

                data = data + newdata

            decdata = decdata + decdatacur

            wtd = totalwtd - len(decdata)

            if not decdata and not self.eof:

                raise Error, 'Premature EOF on binhex file'

        return decdata

    def close(self):

        self.ifp.close()

class _Rledecoderengine:

    """Read data via the RLE-coder"""

    def __init__(self, ifp):

        self.ifp = ifp

        self.pre_buffer = ''

        self.post_buffer = ''

        self.eof = 0

    def read(self, wtd):

        if wtd > len(self.post_buffer):

            self._fill(wtd-len(self.post_buffer))

        rv = self.post_buffer[:wtd]

        self.post_buffer = self.post_buffer[wtd:]

        return rv

    def _fill(self, wtd):

        self.pre_buffer = self.pre_buffer + self.ifp.read(wtd+4)

        if self.ifp.eof:

            self.post_buffer = self.post_buffer + \

                binascii.rledecode_hqx(self.pre_buffer)

            self.pre_buffer = ''

            return

        #

        # Obfuscated code ahead. We have to take care that we don't

        # end up with an orphaned RUNCHAR later on. So, we keep a couple

        # of bytes in the buffer, depending on what the end of

        # the buffer looks like:

        # '\220\0\220' - Keep 3 bytes: repeated \220 (escaped as \220\0)

        # '?\220' - Keep 2 bytes: repeated something-else

        # '\220\0' - Escaped \220: Keep 2 bytes.

        # '?\220?' - Complete repeat sequence: decode all

        # otherwise: keep 1 byte.

        #

        mark = len(self.pre_buffer)

        if self.pre_buffer[-3:] == RUNCHAR + '\0' + RUNCHAR:

            mark = mark - 3

        elif self.pre_buffer[-1] == RUNCHAR:

            mark = mark - 2

        elif self.pre_buffer[-2:] == RUNCHAR + '\0':

            mark = mark - 2

        elif self.pre_buffer[-2] == RUNCHAR:

            pass # Decode all

        else:

            mark = mark - 1

        self.post_buffer = self.post_buffer + \

            binascii.rledecode_hqx(self.pre_buffer[:mark])

        self.pre_buffer = self.pre_buffer[mark:]

    def close(self):

        self.ifp.close()

class HexBin:

    def __init__(self, ifp):

        if type(ifp) == type(''):

            ifp = open(ifp)

        #

        # Find initial colon.

        #

        while 1:

            ch = ifp.read(1)

            if not ch:

                raise Error, "No binhex data found"

            # Cater for \r\n terminated lines (which show up as \n\r, hence

            # all lines start with \r)

            if ch == '\r':

                continue

            if ch == ':':

                break

            if ch != '\n':

                dummy = ifp.readline()

        hqxifp = _Hqxdecoderengine(ifp)

        self.ifp = _Rledecoderengine(hqxifp)

        self.crc = 0

        self._readheader()

    def _read(self, len):

        data = self.ifp.read(len)

        self.crc = binascii.crc_hqx(data, self.crc)

        return data

    def _checkcrc(self):

        filecrc = struct.unpack('>h', self.ifp.read(2))[0] & 0xffff

        #self.crc = binascii.crc_hqx('\0\0', self.crc)

        # XXXX Is this needed??

        self.crc = self.crc & 0xffff

        if filecrc != self.crc:

            raise Error, 'CRC error, computed %x, read %x' \

                  %(self.crc, filecrc)

        self.crc = 0

    def _readheader(self):

        len = self._read(1)

        fname = self._read(ord(len))

        rest = self._read(1+4+4+2+4+4)

        self._checkcrc()

        type = rest[1:5]

        creator = rest[5:9]

        flags = struct.unpack('>h', rest[9:11])[0]

        self.dlen = struct.unpack('>l', rest[11:15])[0]

        self.rlen = struct.unpack('>l', rest[15:19])[0]

        self.FName = fname

        self.FInfo = FInfo()

        self.FInfo.Creator = creator

        self.FInfo.Type = type

        self.FInfo.Flags = flags

        self.state = _DID_HEADER

    def read(self, *n):

        if self.state != _DID_HEADER:

            raise Error, 'Read data at wrong time'

        if n:

            n = n[0]

            n = min(n, self.dlen)

        else:

            n = self.dlen

        rv = ''

        while len(rv) < n:

            rv = rv + self._read(n-len(rv))

        self.dlen = self.dlen - n

        return rv

    def close_data(self):

        if self.state != _DID_HEADER:

            raise Error, 'close_data at wrong time'

        if self.dlen:

            dummy = self._read(self.dlen)

        self._checkcrc()

        self.state = _DID_DATA

    def read_rsrc(self, *n):

        if self.state == _DID_HEADER:

            self.close_data()

        if self.state != _DID_DATA:

            raise Error, 'Read resource data at wrong time'

        if n:

            n = n[0]

            n = min(n, self.rlen)

        else:

            n = self.rlen

        self.rlen = self.rlen - n

        return self._read(n)

    def close(self):

        if self.rlen:

            dummy = self.read_rsrc(self.rlen)

        self._checkcrc()

        self.state = _DID_RSRC

        self.ifp.close()

def hexbin(inp, out):

    """(infilename, outfilename) - Decode binhexed file"""

    ifp = HexBin(inp)

    finfo = ifp.FInfo

    if not out:

        out = ifp.FName

    if os.name == 'mac':

        ofss = FSSpec(out)

        out = ofss.as_pathname()

    ofp = open(out, 'wb')

    # XXXX Do translation on non-mac systems

    while 1:

        d = ifp.read(128000)

        if not d: break

        ofp.write(d)

    ofp.close()

    ifp.close_data()

    d = ifp.read_rsrc(128000)

    if d:

        ofp = openrsrc(out, 'wb')

        ofp.write(d)

        while 1:

            d = ifp.read_rsrc(128000)

            if not d: break

            ofp.write(d)

        ofp.close()

    if os.name == 'mac':

        nfinfo = ofss.GetFInfo()

        nfinfo.Creator = finfo.Creator

        nfinfo.Type = finfo.Type

        nfinfo.Flags = finfo.Flags

        ofss.SetFInfo(nfinfo)

    ifp.close()

def _test():

    fname = sys.argv[1]

    binhex(fname, fname+'.hqx')

    hexbin(fname+'.hqx', fname+'.viahqx')

    #hexbin(fname, fname+'.unpacked')

    sys.exit(1)

if __name__ == '__main__':

    _test()