"""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 io
import os
import struct
import binascii

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

class Error(Exception):
 pass

# States (what have we written)
_DID_HEADER = 0
_DID_DATA = 1

# Various constants
REASONABLY_LARGE = 32768 # Minimal amount we pass the rle-coder
LINELEN = 64
RUNCHAR = b"\x90"

#
# This code is no longer byte-order dependent


class FInfo:
 def __init__(self):
 self.Type = '????'
 self.Creator = '????'
 self.Flags = 0

def getfileinfo(name):
 finfo = FInfo()
 with io.open(name, 'rb') as fp:
 # Quick check for textfile
 data = fp.read(512)
 if 0 not in data:
 finfo.Type = 'TEXT'
 fp.seek(0, 2)
 dsize = fp.tell()
 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 b''

 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 = b''
 self.hqxdata = b''
 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] + b'\r')
 self.linelen = LINELEN
 first = last
 self.hqxdata = self.hqxdata[first:]
 if force:
 self.ofp.write(self.hqxdata + b':\r')

 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 = b''

 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 = b''

 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):
 name, finfo, dlen, rlen = name_finfo_dlen_rlen
 close_on_error = False
 if isinstance(ofp, str):
 ofname = ofp
 ofp = io.open(ofname, 'wb')
 close_on_error = True
 try:
 ofp.write(b'(This file must be converted with BinHex 4.0)\r\r:')
 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
 except:
 if close_on_error:
 ofp.close()
 raise

 def _writeinfo(self, name, finfo):
 nl = len(name)
 if nl > 63:
 raise Error('Filename too long')
 d = bytes([nl]) + name.encode("latin-1") + b'0円'
 tp, cr = finfo.Type, finfo.Creator
 if isinstance(tp, str):
 tp = tp.encode("latin-1")
 if isinstance(cr, str):
 cr = cr.encode("latin-1")
 d2 = tp + cr

 # 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円0円', 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 is None:
 return
 try:
 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()
 finally:
 self.state = None
 ofp = self.ofp
 del self.ofp
 ofp.close()

def binhex(inp, out):
 """binhex(infilename, outfilename): create binhex-encoded copy of a file"""
 finfo = getfileinfo(inp)
 ofp = BinHex(finfo, out)

 with io.open(inp, 'rb') as ifp:
 # XXXX Do textfile translation on non-mac systems
 while True:
 d = ifp.read(128000)
 if not d: break
 ofp.write(d)
 ofp.close_data()

 ifp = openrsrc(inp, 'rb')
 while True:
 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 = b''
 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 True:
 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 = b''
 self.post_buffer = b''
 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 = b''
 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円0円220円' - Keep 3 bytes: repeated 220円 (escaped as 220円0円)
 # '?220円' - Keep 2 bytes: repeated something-else
 # '220円0円' - Escaped 220円: Keep 2 bytes.
 # '?220円?' - Complete repeat sequence: decode all
 # otherwise: keep 1 byte.
 #
 mark = len(self.pre_buffer)
 if self.pre_buffer[-3:] == RUNCHAR + b'0円' + RUNCHAR:
 mark = mark - 3
 elif self.pre_buffer[-1:] == RUNCHAR:
 mark = mark - 2
 elif self.pre_buffer[-2:] == RUNCHAR + b'0円':
 mark = mark - 2
 elif self.pre_buffer[-2:-1] == 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 isinstance(ifp, str):
 ifp = io.open(ifp, 'rb')
 #
 # Find initial colon.
 #
 while True:
 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 == b'\r':
 continue
 if ch == b':':
 break

 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円0円', 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 = b''
 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.state is None:
 return
 try:
 if self.rlen:
 dummy = self.read_rsrc(self.rlen)
 self._checkcrc()
 finally:
 self.state = None
 self.ifp.close()

def hexbin(inp, out):
 """hexbin(infilename, outfilename) - Decode binhexed file"""
 ifp = HexBin(inp)
 finfo = ifp.FInfo
 if not out:
 out = ifp.FName

 with io.open(out, 'wb') as ofp:
 # XXXX Do translation on non-mac systems
 while True:
 d = ifp.read(128000)
 if not d: break
 ofp.write(d)
 ifp.close_data()

 d = ifp.read_rsrc(128000)
 if d:
 ofp = openrsrc(out, 'wb')
 ofp.write(d)
 while True:
 d = ifp.read_rsrc(128000)
 if not d: break
 ofp.write(d)
 ofp.close()

 ifp.close()