Fix #1247. Add two additional audio format libraries.

Lib/aifc.py

@@ -0,0 +1,951 @@
+"""Stuff to parse AIFF-C and AIFF files.
+
+Unless explicitly stated otherwise, the description below is true
+both for AIFF-C files and AIFF files.
+
+An AIFF-C file has the following structure.
+
+  +-----------------+
+  | FORM            |
+  +-----------------+
+  | <size>          |
+  +----+------------+
+  |    | AIFC       |
+  |    +------------+
+  |    | <chunks>   |
+  |    |    .       |
+  |    |    .       |
+  |    |    .       |
+  +----+------------+
+
+An AIFF file has the string "AIFF" instead of "AIFC".
+
+A chunk consists of an identifier (4 bytes) followed by a size (4 bytes,
+big endian order), followed by the data.  The size field does not include
+the size of the 8 byte header.
+
+The following chunk types are recognized.
+
+  FVER
+      <version number of AIFF-C defining document> (AIFF-C only).
+  MARK
+      <# of markers> (2 bytes)
+      list of markers:
+          <marker ID> (2 bytes, must be > 0)
+          <position> (4 bytes)
+          <marker name> ("pstring")
+  COMM
+      <# of channels> (2 bytes)
+      <# of sound frames> (4 bytes)
+      <size of the samples> (2 bytes)
+      <sampling frequency> (10 bytes, IEEE 80-bit extended
+          floating point)
+      in AIFF-C files only:
+      <compression type> (4 bytes)
+      <human-readable version of compression type> ("pstring")
+  SSND
+      <offset> (4 bytes, not used by this program)
+      <blocksize> (4 bytes, not used by this program)
+      <sound data>
+
+A pstring consists of 1 byte length, a string of characters, and 0 or 1
+byte pad to make the total length even.
+
+Usage.
+
+Reading AIFF files:
+  f = aifc.open(file, 'r')
+where file is either the name of a file or an open file pointer.
+The open file pointer must have methods read(), seek(), and close().
+In some types of audio files, if the setpos() method is not used,
+the seek() method is not necessary.
+
+This returns an instance of a class with the following public methods:
+  getnchannels()  -- returns number of audio channels (1 for
+             mono, 2 for stereo)
+  getsampwidth()  -- returns sample width in bytes
+  getframerate()  -- returns sampling frequency
+  getnframes()    -- returns number of audio frames
+  getcomptype()   -- returns compression type ('NONE' for AIFF files)
+  getcompname()   -- returns human-readable version of
+             compression type ('not compressed' for AIFF files)
+  getparams() -- returns a namedtuple consisting of all of the
+             above in the above order
+  getmarkers()    -- get the list of marks in the audio file or None
+             if there are no marks
+  getmark(id) -- get mark with the specified id (raises an error
+             if the mark does not exist)
+  readframes(n)   -- returns at most n frames of audio
+  rewind()    -- rewind to the beginning of the audio stream
+  setpos(pos) -- seek to the specified position
+  tell()      -- return the current position
+  close()     -- close the instance (make it unusable)
+The position returned by tell(), the position given to setpos() and
+the position of marks are all compatible and have nothing to do with
+the actual position in the file.
+The close() method is called automatically when the class instance
+is destroyed.
+
+Writing AIFF files:
+  f = aifc.open(file, 'w')
+where file is either the name of a file or an open file pointer.
+The open file pointer must have methods write(), tell(), seek(), and
+close().
+
+This returns an instance of a class with the following public methods:
+  aiff()      -- create an AIFF file (AIFF-C default)
+  aifc()      -- create an AIFF-C file
+  setnchannels(n) -- set the number of channels
+  setsampwidth(n) -- set the sample width
+  setframerate(n) -- set the frame rate
+  setnframes(n)   -- set the number of frames
+  setcomptype(type, name)
+          -- set the compression type and the
+             human-readable compression type
+  setparams(tuple)
+          -- set all parameters at once
+  setmark(id, pos, name)
+          -- add specified mark to the list of marks
+  tell()      -- return current position in output file (useful
+             in combination with setmark())
+  writeframesraw(data)
+          -- write audio frames without pathing up the
+             file header
+  writeframes(data)
+          -- write audio frames and patch up the file header
+  close()     -- patch up the file header and close the
+             output file
+You should set the parameters before the first writeframesraw or
+writeframes.  The total number of frames does not need to be set,
+but when it is set to the correct value, the header does not have to
+be patched up.
+It is best to first set all parameters, perhaps possibly the
+compression type, and then write audio frames using writeframesraw.
+When all frames have been written, either call writeframes(b'') or
+close() to patch up the sizes in the header.
+Marks can be added anytime.  If there are any marks, you must call
+close() after all frames have been written.
+The close() method is called automatically when the class instance
+is destroyed.
+
+When a file is opened with the extension '.aiff', an AIFF file is
+written, otherwise an AIFF-C file is written.  This default can be
+changed by calling aiff() or aifc() before the first writeframes or
+writeframesraw.
+"""
+
+import struct
+import builtins
+import warnings
+
+__all__ = ["Error", "open", "openfp"]
+
+class Error(Exception):
+    pass
+
+_AIFC_version = 0xA2805140     # Version 1 of AIFF-C
+
+def _read_long(file):
+    try:
+        return struct.unpack('>l', file.read(4))[0]
+    except struct.error:
+        raise EOFError from None
+
+def _read_ulong(file):
+    try:
+        return struct.unpack('>L', file.read(4))[0]
+    except struct.error:
+        raise EOFError from None
+
+def _read_short(file):
+    try:
+        return struct.unpack('>h', file.read(2))[0]
+    except struct.error:
+        raise EOFError from None
+
+def _read_ushort(file):
+    try:
+        return struct.unpack('>H', file.read(2))[0]
+    except struct.error:
+        raise EOFError from None
+
+def _read_string(file):
+    length = ord(file.read(1))
+    if length == 0:
+        data = b''
+    else:
+        data = file.read(length)
+    if length & 1 == 0:
+        dummy = file.read(1)
+    return data
+
+_HUGE_VAL = 1.79769313486231e+308 # See <limits.h>
+
+def _read_float(f): # 10 bytes
+    expon = _read_short(f) # 2 bytes
+    sign = 1
+    if expon < 0:
+        sign = -1
+        expon = expon + 0x8000
+    himant = _read_ulong(f) # 4 bytes
+    lomant = _read_ulong(f) # 4 bytes
+    if expon == himant == lomant == 0:
+        f = 0.0
+    elif expon == 0x7FFF:
+        f = _HUGE_VAL
+    else:
+        expon = expon - 16383
+        f = (himant * 0x100000000 + lomant) * pow(2.0, expon - 63)
+    return sign * f
+
+def _write_short(f, x):
+    f.write(struct.pack('>h', x))
+
+def _write_ushort(f, x):
+    f.write(struct.pack('>H', x))
+
+def _write_long(f, x):
+    f.write(struct.pack('>l', x))
+
+def _write_ulong(f, x):
+    f.write(struct.pack('>L', x))
+
+def _write_string(f, s):
+    if len(s) > 255:
+        raise ValueError("string exceeds maximum pstring length")
+    f.write(struct.pack('B', len(s)))
+    f.write(s)
+    if len(s) & 1 == 0:
+        f.write(b'\x00')
+
+def _write_float(f, x):
+    import math
+    if x < 0:
+        sign = 0x8000
+        x = x * -1
+    else:
+        sign = 0
+    if x == 0:
+        expon = 0
+        himant = 0
+        lomant = 0
+    else:
+        fmant, expon = math.frexp(x)
+        if expon > 16384 or fmant >= 1 or fmant != fmant: # Infinity or NaN
+            expon = sign|0x7FFF
+            himant = 0
+            lomant = 0
+        else:                   # Finite
+            expon = expon + 16382
+            if expon < 0:           # denormalized
+                fmant = math.ldexp(fmant, expon)
+                expon = 0
+            expon = expon | sign
+            fmant = math.ldexp(fmant, 32)
+            fsmant = math.floor(fmant)
+            himant = int(fsmant)
+            fmant = math.ldexp(fmant - fsmant, 32)
+            fsmant = math.floor(fmant)
+            lomant = int(fsmant)
+    _write_ushort(f, expon)
+    _write_ulong(f, himant)
+    _write_ulong(f, lomant)
+
+from chunk import Chunk
+from collections import namedtuple
+
+_aifc_params = namedtuple('_aifc_params',
+                          'nchannels sampwidth framerate nframes comptype compname')
+
+_aifc_params.nchannels.__doc__ = 'Number of audio channels (1 for mono, 2 for stereo)'
+_aifc_params.sampwidth.__doc__ = 'Sample width in bytes'
+_aifc_params.framerate.__doc__ = 'Sampling frequency'
+_aifc_params.nframes.__doc__ = 'Number of audio frames'
+_aifc_params.comptype.__doc__ = 'Compression type ("NONE" for AIFF files)'
+_aifc_params.compname.__doc__ = ("""\
+A human-readable version of the compression type
+('not compressed' for AIFF files)""")
+
+
+class Aifc_read:
+    # Variables used in this class:
+    #
+    # These variables are available to the user though appropriate
+    # methods of this class:
+    # _file -- the open file with methods read(), close(), and seek()
+    #       set through the __init__() method
+    # _nchannels -- the number of audio channels
+    #       available through the getnchannels() method
+    # _nframes -- the number of audio frames
+    #       available through the getnframes() method
+    # _sampwidth -- the number of bytes per audio sample
+    #       available through the getsampwidth() method
+    # _framerate -- the sampling frequency
+    #       available through the getframerate() method
+    # _comptype -- the AIFF-C compression type ('NONE' if AIFF)
+    #       available through the getcomptype() method
+    # _compname -- the human-readable AIFF-C compression type
+    #       available through the getcomptype() method
+    # _markers -- the marks in the audio file
+    #       available through the getmarkers() and getmark()
+    #       methods
+    # _soundpos -- the position in the audio stream
+    #       available through the tell() method, set through the
+    #       setpos() method
+    #
+    # These variables are used internally only:
+    # _version -- the AIFF-C version number
+    # _decomp -- the decompressor from builtin module cl
+    # _comm_chunk_read -- 1 iff the COMM chunk has been read
+    # _aifc -- 1 iff reading an AIFF-C file
+    # _ssnd_seek_needed -- 1 iff positioned correctly in audio
+    #       file for readframes()
+    # _ssnd_chunk -- instantiation of a chunk class for the SSND chunk
+    # _framesize -- size of one frame in the file
+
+    _file = None  # Set here since __del__ checks it
+
+    def initfp(self, file):
+        self._version = 0
+        self._convert = None
+        self._markers = []
+        self._soundpos = 0
+        self._file = file
+        chunk = Chunk(file)
+        if chunk.getname() != b'FORM':
+            raise Error('file does not start with FORM id')
+        formdata = chunk.read(4)
+        if formdata == b'AIFF':
+            self._aifc = 0
+        elif formdata == b'AIFC':
+            self._aifc = 1
+        else:
+            raise Error('not an AIFF or AIFF-C file')
+        self._comm_chunk_read = 0
+        self._ssnd_chunk = None
+        while 1:
+            self._ssnd_seek_needed = 1
+            try:
+                chunk = Chunk(self._file)
+            except EOFError:
+                break
+            chunkname = chunk.getname()
+            if chunkname == b'COMM':
+                self._read_comm_chunk(chunk)
+                self._comm_chunk_read = 1
+            elif chunkname == b'SSND':
+                self._ssnd_chunk = chunk
+                dummy = chunk.read(8)
+                self._ssnd_seek_needed = 0
+            elif chunkname == b'FVER':
+                self._version = _read_ulong(chunk)
+            elif chunkname == b'MARK':
+                self._readmark(chunk)
+            chunk.skip()
+        if not self._comm_chunk_read or not self._ssnd_chunk:
+            raise Error('COMM chunk and/or SSND chunk missing')
+
+    def __init__(self, f):
+        if isinstance(f, str):
+            file_object = builtins.open(f, 'rb')
+            try:
+                self.initfp(file_object)
+            except:
+                file_object.close()
+                raise
+        else:
+            # assume it is an open file object already
+            self.initfp(f)
+
+    def __enter__(self):
+        return self
+
+    def __exit__(self, *args):
+        self.close()
+
+    #
+    # User visible methods.
+    #
+    def getfp(self):
+        return self._file
+
+    def rewind(self):
+        self._ssnd_seek_needed = 1
+        self._soundpos = 0
+
+    def close(self):
+        file = self._file
+        if file is not None:
+            self._file = None
+            file.close()
+
+    def tell(self):
+        return self._soundpos
+
+    def getnchannels(self):
+        return self._nchannels
+
+    def getnframes(self):
+        return self._nframes
+
+    def getsampwidth(self):
+        return self._sampwidth
+
+    def getframerate(self):
+        return self._framerate
+
+    def getcomptype(self):
+        return self._comptype
+
+    def getcompname(self):
+        return self._compname
+
+##  def getversion(self):
+##      return self._version
+
+    def getparams(self):
+        return _aifc_params(self.getnchannels(), self.getsampwidth(),
+                            self.getframerate(), self.getnframes(),
+                            self.getcomptype(), self.getcompname())
+
+    def getmarkers(self):
+        if len(self._markers) == 0:
+            return None
+        return self._markers
+
+    def getmark(self, id):
+        for marker in self._markers:
+            if id == marker[0]:
+                return marker
+        raise Error('marker {0!r} does not exist'.format(id))
+
+    def setpos(self, pos):
+        if pos < 0 or pos > self._nframes:
+            raise Error('position not in range')
+        self._soundpos = pos
+        self._ssnd_seek_needed = 1
+
+    def readframes(self, nframes):
+        if self._ssnd_seek_needed:
+            self._ssnd_chunk.seek(0)
+            dummy = self._ssnd_chunk.read(8)
+            pos = self._soundpos * self._framesize
+            if pos:
+                self._ssnd_chunk.seek(pos + 8)
+            self._ssnd_seek_needed = 0
+        if nframes == 0:
+            return b''
+        data = self._ssnd_chunk.read(nframes * self._framesize)
+        if self._convert and data:
+            data = self._convert(data)
+        self._soundpos = self._soundpos + len(data) // (self._nchannels
+                                                        * self._sampwidth)
+        return data
+
+    #
+    # Internal methods.
+    #
+
+    def _alaw2lin(self, data):
+        import audioop
+        return audioop.alaw2lin(data, 2)
+
+    def _ulaw2lin(self, data):
+        import audioop
+        return audioop.ulaw2lin(data, 2)
+
+    def _adpcm2lin(self, data):
+        import audioop
+        if not hasattr(self, '_adpcmstate'):
+            # first time
+            self._adpcmstate = None
+        data, self._adpcmstate = audioop.adpcm2lin(data, 2, self._adpcmstate)
+        return data
+
+    def _read_comm_chunk(self, chunk):
+        self._nchannels = _read_short(chunk)
+        self._nframes = _read_long(chunk)
+        self._sampwidth = (_read_short(chunk) + 7) // 8
+        self._framerate = int(_read_float(chunk))
+        if self._sampwidth <= 0:
+            raise Error('bad sample width')
+        if self._nchannels <= 0:
+            raise Error('bad # of channels')
+        self._framesize = self._nchannels * self._sampwidth
+        if self._aifc:
+            #DEBUG: SGI's soundeditor produces a bad size :-(
+            kludge = 0
+            if chunk.chunksize == 18:
+                kludge = 1
+                warnings.warn('Warning: bad COMM chunk size')
+                chunk.chunksize = 23
+            #DEBUG end
+            self._comptype = chunk.read(4)
+            #DEBUG start
+            if kludge:
+                length = ord(chunk.file.read(1))
+                if length & 1 == 0:
+                    length = length + 1
+                chunk.chunksize = chunk.chunksize + length
+                chunk.file.seek(-1, 1)
+            #DEBUG end
+            self._compname = _read_string(chunk)
+            if self._comptype != b'NONE':
+                if self._comptype == b'G722':
+                    self._convert = self._adpcm2lin
+                elif self._comptype in (b'ulaw', b'ULAW'):
+                    self._convert = self._ulaw2lin
+                elif self._comptype in (b'alaw', b'ALAW'):
+                    self._convert = self._alaw2lin
+                else:
+                    raise Error('unsupported compression type')
+                self._sampwidth = 2
+        else:
+            self._comptype = b'NONE'
+            self._compname = b'not compressed'
+
+    def _readmark(self, chunk):
+        nmarkers = _read_short(chunk)
+        # Some files appear to contain invalid counts.
+        # Cope with this by testing for EOF.
+        try:
+            for i in range(nmarkers):
+                id = _read_short(chunk)
+                pos = _read_long(chunk)
+                name = _read_string(chunk)
+                if pos or name:
+                    # some files appear to have
+                    # dummy markers consisting of
+                    # a position 0 and name ''
+                    self._markers.append((id, pos, name))
+        except EOFError:
+            w = ('Warning: MARK chunk contains only %s marker%s instead of %s' %
+                 (len(self._markers), '' if len(self._markers) == 1 else 's',
+                  nmarkers))
+            warnings.warn(w)
+
+class Aifc_write:
+    # Variables used in this class:
+    #
+    # These variables are user settable through appropriate methods
+    # of this class:
+    # _file -- the open file with methods write(), close(), tell(), seek()
+    #       set through the __init__() method
+    # _comptype -- the AIFF-C compression type ('NONE' in AIFF)
+    #       set through the setcomptype() or setparams() method
+    # _compname -- the human-readable AIFF-C compression type
+    #       set through the setcomptype() or setparams() method
+    # _nchannels -- the number of audio channels
+    #       set through the setnchannels() or setparams() method
+    # _sampwidth -- the number of bytes per audio sample
+    #       set through the setsampwidth() or setparams() method
+    # _framerate -- the sampling frequency
+    #       set through the setframerate() or setparams() method
+    # _nframes -- the number of audio frames written to the header
+    #       set through the setnframes() or setparams() method
+    # _aifc -- whether we're writing an AIFF-C file or an AIFF file
+    #       set through the aifc() method, reset through the
+    #       aiff() method
+    #
+    # These variables are used internally only:
+    # _version -- the AIFF-C version number
+    # _comp -- the compressor from builtin module cl
+    # _nframeswritten -- the number of audio frames actually written
+    # _datalength -- the size of the audio samples written to the header
+    # _datawritten -- the size of the audio samples actually written
+
+    _file = None  # Set here since __del__ checks it
+
+    def __init__(self, f):
+        if isinstance(f, str):
+            file_object = builtins.open(f, 'wb')
+            try:
+                self.initfp(file_object)
+            except:
+                file_object.close()
+                raise
+
+            # treat .aiff file extensions as non-compressed audio
+            if f.endswith('.aiff'):
+                self._aifc = 0
+        else:
+            # assume it is an open file object already
+            self.initfp(f)
+
+    def initfp(self, file):
+        self._file = file
+        self._version = _AIFC_version
+        self._comptype = b'NONE'
+        self._compname = b'not compressed'
+        self._convert = None
+        self._nchannels = 0
+        self._sampwidth = 0
+        self._framerate = 0
+        self._nframes = 0
+        self._nframeswritten = 0
+        self._datawritten = 0
+        self._datalength = 0
+        self._markers = []
+        self._marklength = 0
+        self._aifc = 1      # AIFF-C is default
+
+    def __del__(self):
+        self.close()
+
+    def __enter__(self):
+        return self
+
+    def __exit__(self, *args):
+        self.close()
+
+    #
+    # User visible methods.
+    #
+    def aiff(self):
+        if self._nframeswritten:
+            raise Error('cannot change parameters after starting to write')
+        self._aifc = 0
+
+    def aifc(self):
+        if self._nframeswritten:
+            raise Error('cannot change parameters after starting to write')
+        self._aifc = 1
+
+    def setnchannels(self, nchannels):
+        if self._nframeswritten:
+            raise Error('cannot change parameters after starting to write')
+        if nchannels < 1:
+            raise Error('bad # of channels')
+        self._nchannels = nchannels
+
+    def getnchannels(self):
+        if not self._nchannels:
+            raise Error('number of channels not set')
+        return self._nchannels
+
+    def setsampwidth(self, sampwidth):
+        if self._nframeswritten:
+            raise Error('cannot change parameters after starting to write')
+        if sampwidth < 1 or sampwidth > 4:
+            raise Error('bad sample width')
+        self._sampwidth = sampwidth
+
+    def getsampwidth(self):
+        if not self._sampwidth:
+            raise Error('sample width not set')
+        return self._sampwidth
+
+    def setframerate(self, framerate):
+        if self._nframeswritten:
+            raise Error('cannot change parameters after starting to write')
+        if framerate <= 0:
+            raise Error('bad frame rate')
+        self._framerate = framerate
+
+    def getframerate(self):
+        if not self._framerate:
+            raise Error('frame rate not set')
+        return self._framerate
+
+    def setnframes(self, nframes):
+        if self._nframeswritten:
+            raise Error('cannot change parameters after starting to write')
+        self._nframes = nframes
+
+    def getnframes(self):
+        return self._nframeswritten
+
+    def setcomptype(self, comptype, compname):
+        if self._nframeswritten:
+            raise Error('cannot change parameters after starting to write')
+        if comptype not in (b'NONE', b'ulaw', b'ULAW',
+                            b'alaw', b'ALAW', b'G722'):
+            raise Error('unsupported compression type')
+        self._comptype = comptype
+        self._compname = compname
+
+    def getcomptype(self):
+        return self._comptype
+
+    def getcompname(self):
+        return self._compname
+
+##  def setversion(self, version):
+##      if self._nframeswritten:
+##          raise Error, 'cannot change parameters after starting to write'
+##      self._version = version
+
+    def setparams(self, params):
+        nchannels, sampwidth, framerate, nframes, comptype, compname = params
+        if self._nframeswritten:
+            raise Error('cannot change parameters after starting to write')
+        if comptype not in (b'NONE', b'ulaw', b'ULAW',
+                            b'alaw', b'ALAW', b'G722'):
+            raise Error('unsupported compression type')
+        self.setnchannels(nchannels)
+        self.setsampwidth(sampwidth)
+        self.setframerate(framerate)
+        self.setnframes(nframes)
+        self.setcomptype(comptype, compname)
+
+    def getparams(self):
+        if not self._nchannels or not self._sampwidth or not self._framerate:
+            raise Error('not all parameters set')
+        return _aifc_params(self._nchannels, self._sampwidth, self._framerate,
+                            self._nframes, self._comptype, self._compname)
+
+    def setmark(self, id, pos, name):
+        if id <= 0:
+            raise Error('marker ID must be > 0')
+        if pos < 0:
+            raise Error('marker position must be >= 0')
+        if not isinstance(name, bytes):
+            raise Error('marker name must be bytes')
+        for i in range(len(self._markers)):
+            if id == self._markers[i][0]:
+                self._markers[i] = id, pos, name
+                return
+        self._markers.append((id, pos, name))
+
+    def getmark(self, id):
+        for marker in self._markers:
+            if id == marker[0]:
+                return marker
+        raise Error('marker {0!r} does not exist'.format(id))
+
+    def getmarkers(self):
+        if len(self._markers) == 0:
+            return None
+        return self._markers
+
+    def tell(self):
+        return self._nframeswritten
+
+    def writeframesraw(self, data):
+        if not isinstance(data, (bytes, bytearray)):
+            data = memoryview(data).cast('B')
+        self._ensure_header_written(len(data))
+        nframes = len(data) // (self._sampwidth * self._nchannels)
+        if self._convert:
+            data = self._convert(data)
+        self._file.write(data)
+        self._nframeswritten = self._nframeswritten + nframes
+        self._datawritten = self._datawritten + len(data)
+
+    def writeframes(self, data):
+        self.writeframesraw(data)
+        if self._nframeswritten != self._nframes or \
+              self._datalength != self._datawritten:
+            self._patchheader()
+
+    def close(self):
+        if self._file is None:
+            return
+        try:
+            self._ensure_header_written(0)
+            if self._datawritten & 1:
+                # quick pad to even size
+                self._file.write(b'\x00')
+                self._datawritten = self._datawritten + 1
+            self._writemarkers()
+            if self._nframeswritten != self._nframes or \
+                  self._datalength != self._datawritten or \
+                  self._marklength:
+                self._patchheader()
+        finally:
+            # Prevent ref cycles
+            self._convert = None
+            f = self._file
+            self._file = None
+            f.close()
+
+    #
+    # Internal methods.
+    #
+
+    def _lin2alaw(self, data):
+        import audioop
+        return audioop.lin2alaw(data, 2)
+
+    def _lin2ulaw(self, data):
+        import audioop
+        return audioop.lin2ulaw(data, 2)
+
+    def _lin2adpcm(self, data):
+        import audioop
+        if not hasattr(self, '_adpcmstate'):
+            self._adpcmstate = None
+        data, self._adpcmstate = audioop.lin2adpcm(data, 2, self._adpcmstate)
+        return data
+
+    def _ensure_header_written(self, datasize):
+        if not self._nframeswritten:
+            if self._comptype in (b'ULAW', b'ulaw', b'ALAW', b'alaw', b'G722'):
+                if not self._sampwidth:
+                    self._sampwidth = 2
+                if self._sampwidth != 2:
+                    raise Error('sample width must be 2 when compressing '
+                                'with ulaw/ULAW, alaw/ALAW or G7.22 (ADPCM)')
+            if not self._nchannels:
+                raise Error('# channels not specified')
+            if not self._sampwidth:
+                raise Error('sample width not specified')
+            if not self._framerate:
+                raise Error('sampling rate not specified')
+            self._write_header(datasize)
+
+    def _init_compression(self):
+        if self._comptype == b'G722':
+            self._convert = self._lin2adpcm
+        elif self._comptype in (b'ulaw', b'ULAW'):
+            self._convert = self._lin2ulaw
+        elif self._comptype in (b'alaw', b'ALAW'):
+            self._convert = self._lin2alaw
+
+    def _write_header(self, initlength):
+        if self._aifc and self._comptype != b'NONE':
+            self._init_compression()
+        self._file.write(b'FORM')
+        if not self._nframes:
+            self._nframes = initlength // (self._nchannels * self._sampwidth)
+        self._datalength = self._nframes * self._nchannels * self._sampwidth
+        if self._datalength & 1:
+            self._datalength = self._datalength + 1
+        if self._aifc:
+            if self._comptype in (b'ulaw', b'ULAW', b'alaw', b'ALAW'):
+                self._datalength = self._datalength // 2
+                if self._datalength & 1:
+                    self._datalength = self._datalength + 1
+            elif self._comptype == b'G722':
+                self._datalength = (self._datalength + 3) // 4
+                if self._datalength & 1:
+                    self._datalength = self._datalength + 1
+        try:
+            self._form_length_pos = self._file.tell()
+        except (AttributeError, OSError):
+            self._form_length_pos = None
+        commlength = self._write_form_length(self._datalength)
+        if self._aifc:
+            self._file.write(b'AIFC')
+            self._file.write(b'FVER')
+            _write_ulong(self._file, 4)
+            _write_ulong(self._file, self._version)
+        else:
+            self._file.write(b'AIFF')
+        self._file.write(b'COMM')
+        _write_ulong(self._file, commlength)
+        _write_short(self._file, self._nchannels)
+        if self._form_length_pos is not None:
+            self._nframes_pos = self._file.tell()
+        _write_ulong(self._file, self._nframes)
+        if self._comptype in (b'ULAW', b'ulaw', b'ALAW', b'alaw', b'G722'):
+            _write_short(self._file, 8)
+        else:
+            _write_short(self._file, self._sampwidth * 8)
+        _write_float(self._file, self._framerate)
+        if self._aifc:
+            self._file.write(self._comptype)
+            _write_string(self._file, self._compname)
+        self._file.write(b'SSND')
+        if self._form_length_pos is not None:
+            self._ssnd_length_pos = self._file.tell()
+        _write_ulong(self._file, self._datalength + 8)
+        _write_ulong(self._file, 0)
+        _write_ulong(self._file, 0)
+
+    def _write_form_length(self, datalength):
+        if self._aifc:
+            commlength = 18 + 5 + len(self._compname)
+            if commlength & 1:
+                commlength = commlength + 1
+            verslength = 12
+        else:
+            commlength = 18
+            verslength = 0
+        _write_ulong(self._file, 4 + verslength + self._marklength + \
+                     8 + commlength + 16 + datalength)
+        return commlength
+
+    def _patchheader(self):
+        curpos = self._file.tell()
+        if self._datawritten & 1:
+            datalength = self._datawritten + 1
+            self._file.write(b'\x00')
+        else:
+            datalength = self._datawritten
+        if datalength == self._datalength and \
+              self._nframes == self._nframeswritten and \
+              self._marklength == 0:
+            self._file.seek(curpos, 0)
+            return
+        self._file.seek(self._form_length_pos, 0)
+        dummy = self._write_form_length(datalength)
+        self._file.seek(self._nframes_pos, 0)
+        _write_ulong(self._file, self._nframeswritten)
+        self._file.seek(self._ssnd_length_pos, 0)
+        _write_ulong(self._file, datalength + 8)
+        self._file.seek(curpos, 0)
+        self._nframes = self._nframeswritten
+        self._datalength = datalength
+
+    def _writemarkers(self):
+        if len(self._markers) == 0:
+            return
+        self._file.write(b'MARK')
+        length = 2
+        for marker in self._markers:
+            id, pos, name = marker
+            length = length + len(name) + 1 + 6
+            if len(name) & 1 == 0:
+                length = length + 1
+        _write_ulong(self._file, length)
+        self._marklength = length + 8
+        _write_short(self._file, len(self._markers))
+        for marker in self._markers:
+            id, pos, name = marker
+            _write_short(self._file, id)
+            _write_ulong(self._file, pos)
+            _write_string(self._file, name)
+
+def open(f, mode=None):
+    if mode is None:
+        if hasattr(f, 'mode'):
+            mode = f.mode
+        else:
+            mode = 'rb'
+    if mode in ('r', 'rb'):
+        return Aifc_read(f)
+    elif mode in ('w', 'wb'):
+        return Aifc_write(f)
+    else:
+        raise Error("mode must be 'r', 'rb', 'w', or 'wb'")
+
+def openfp(f, mode=None):
+    warnings.warn("aifc.openfp is deprecated since Python 3.7. "
+                  "Use aifc.open instead.", DeprecationWarning, stacklevel=2)
+    return open(f, mode=mode)
+
+if __name__ == '__main__':
+    import sys
+    if not sys.argv[1:]:
+        sys.argv.append('/usr/demos/data/audio/bach.aiff')
+    fn = sys.argv[1]
+    with open(fn, 'r') as f:
+        print("Reading", fn)
+        print("nchannels =", f.getnchannels())
+        print("nframes   =", f.getnframes())
+        print("sampwidth =", f.getsampwidth())
+        print("framerate =", f.getframerate())
+        print("comptype  =", f.getcomptype())
+        print("compname  =", f.getcompname())
+        if sys.argv[2:]:
+            gn = sys.argv[2]
+            print("Writing", gn)
+            with open(gn, 'w') as g:
+                g.setparams(f.getparams())
+                while 1:
+                    data = f.readframes(1024)
+                    if not data:
+                        break
+                    g.writeframes(data)
+            print("Done.")

Lib/sndhdr.py

@@ -0,0 +1,257 @@
+"""Routines to help recognizing sound files.
+
+Function whathdr() recognizes various types of sound file headers.
+It understands almost all headers that SOX can decode.
+
+The return tuple contains the following items, in this order:
+- file type (as SOX understands it)
+- sampling rate (0 if unknown or hard to decode)
+- number of channels (0 if unknown or hard to decode)
+- number of frames in the file (-1 if unknown or hard to decode)
+- number of bits/sample, or 'U' for U-LAW, or 'A' for A-LAW
+
+If the file doesn't have a recognizable type, it returns None.
+If the file can't be opened, OSError is raised.
+
+To compute the total time, divide the number of frames by the
+sampling rate (a frame contains a sample for each channel).
+
+Function what() calls whathdr().  (It used to also use some
+heuristics for raw data, but this doesn't work very well.)
+
+Finally, the function test() is a simple main program that calls
+what() for all files mentioned on the argument list.  For directory
+arguments it calls what() for all files in that directory.  Default
+argument is "." (testing all files in the current directory).  The
+option -r tells it to recurse down directories found inside
+explicitly given directories.
+"""
+
+# The file structure is top-down except that the test program and its
+# subroutine come last.
+
+__all__ = ['what', 'whathdr']
+
+from collections import namedtuple
+
+SndHeaders = namedtuple('SndHeaders',
+                        'filetype framerate nchannels nframes sampwidth')
+
+SndHeaders.filetype.__doc__ = ("""The value for type indicates the data type
+and will be one of the strings 'aifc', 'aiff', 'au','hcom',
+'sndr', 'sndt', 'voc', 'wav', '8svx', 'sb', 'ub', or 'ul'.""")
+SndHeaders.framerate.__doc__ = ("""The sampling_rate will be either the actual
+value or 0 if unknown or difficult to decode.""")
+SndHeaders.nchannels.__doc__ = ("""The number of channels or 0 if it cannot be
+determined or if the value is difficult to decode.""")
+SndHeaders.nframes.__doc__ = ("""The value for frames will be either the number
+of frames or -1.""")
+SndHeaders.sampwidth.__doc__ = ("""Either the sample size in bits or
+'A' for A-LAW or 'U' for u-LAW.""")
+
+def what(filename):
+    """Guess the type of a sound file."""
+    res = whathdr(filename)
+    return res
+
+
+def whathdr(filename):
+    """Recognize sound headers."""
+    with open(filename, 'rb') as f:
+        h = f.read(512)
+        for tf in tests:
+            res = tf(h, f)
+            if res:
+                return SndHeaders(*res)
+        return None
+
+
+#-----------------------------------#
+# Subroutines per sound header type #
+#-----------------------------------#
+
+tests = []
+
+def test_aifc(h, f):
+    import aifc
+    if not h.startswith(b'FORM'):
+        return None
+    if h[8:12] == b'AIFC':
+        fmt = 'aifc'
+    elif h[8:12] == b'AIFF':
+        fmt = 'aiff'
+    else:
+        return None
+    f.seek(0)
+    try:
+        a = aifc.open(f, 'r')
+    except (EOFError, aifc.Error):
+        return None
+    return (fmt, a.getframerate(), a.getnchannels(),
+            a.getnframes(), 8 * a.getsampwidth())
+
+tests.append(test_aifc)
+
+
+def test_au(h, f):
+    if h.startswith(b'.snd'):
+        func = get_long_be
+    elif h[:4] in (b'\0ds.', b'dns.'):
+        func = get_long_le
+    else:
+        return None
+    filetype = 'au'
+    hdr_size = func(h[4:8])
+    data_size = func(h[8:12])
+    encoding = func(h[12:16])
+    rate = func(h[16:20])
+    nchannels = func(h[20:24])
+    sample_size = 1 # default
+    if encoding == 1:
+        sample_bits = 'U'
+    elif encoding == 2:
+        sample_bits = 8
+    elif encoding == 3:
+        sample_bits = 16
+        sample_size = 2
+    else:
+        sample_bits = '?'
+    frame_size = sample_size * nchannels
+    if frame_size:
+        nframe = data_size / frame_size
+    else:
+        nframe = -1
+    return filetype, rate, nchannels, nframe, sample_bits
+
+tests.append(test_au)
+
+
+def test_hcom(h, f):
+    if h[65:69] != b'FSSD' or h[128:132] != b'HCOM':
+        return None
+    divisor = get_long_be(h[144:148])
+    if divisor:
+        rate = 22050 / divisor
+    else:
+        rate = 0
+    return 'hcom', rate, 1, -1, 8
+
+tests.append(test_hcom)
+
+
+def test_voc(h, f):
+    if not h.startswith(b'Creative Voice File\032'):
+        return None
+    sbseek = get_short_le(h[20:22])
+    rate = 0
+    if 0 <= sbseek < 500 and h[sbseek] == 1:
+        ratecode = 256 - h[sbseek+4]
+        if ratecode:
+            rate = int(1000000.0 / ratecode)
+    return 'voc', rate, 1, -1, 8
+
+tests.append(test_voc)
+
+
+def test_wav(h, f):
+    import wave
+    # 'RIFF' <len> 'WAVE' 'fmt ' <len>
+    if not h.startswith(b'RIFF') or h[8:12] != b'WAVE' or h[12:16] != b'fmt ':
+        return None
+    f.seek(0)
+    try:
+        w = wave.open(f, 'r')
+    except (EOFError, wave.Error):
+        return None
+    return ('wav', w.getframerate(), w.getnchannels(),
+                   w.getnframes(), 8*w.getsampwidth())
+
+tests.append(test_wav)
+
+
+def test_8svx(h, f):
+    if not h.startswith(b'FORM') or h[8:12] != b'8SVX':
+        return None
+    # Should decode it to get #channels -- assume always 1
+    return '8svx', 0, 1, 0, 8
+
+tests.append(test_8svx)
+
+
+def test_sndt(h, f):
+    if h.startswith(b'SOUND'):
+        nsamples = get_long_le(h[8:12])
+        rate = get_short_le(h[20:22])
+        return 'sndt', rate, 1, nsamples, 8
+
+tests.append(test_sndt)
+
+
+def test_sndr(h, f):
+    if h.startswith(b'\0\0'):
+        rate = get_short_le(h[2:4])
+        if 4000 <= rate <= 25000:
+            return 'sndr', rate, 1, -1, 8
+
+tests.append(test_sndr)
+
+
+#-------------------------------------------#
+# Subroutines to extract numbers from bytes #
+#-------------------------------------------#
+
+def get_long_be(b):
+    return (b[0] << 24) | (b[1] << 16) | (b[2] << 8) | b[3]
+
+def get_long_le(b):
+    return (b[3] << 24) | (b[2] << 16) | (b[1] << 8) | b[0]
+
+def get_short_be(b):
+    return (b[0] << 8) | b[1]
+
+def get_short_le(b):
+    return (b[1] << 8) | b[0]
+
+
+#--------------------#
+# Small test program #
+#--------------------#
+
+def test():
+    import sys
+    recursive = 0
+    if sys.argv[1:] and sys.argv[1] == '-r':
+        del sys.argv[1:2]
+        recursive = 1
+    try:
+        if sys.argv[1:]:
+            testall(sys.argv[1:], recursive, 1)
+        else:
+            testall(['.'], recursive, 1)
+    except KeyboardInterrupt:
+        sys.stderr.write('\n[Interrupted]\n')
+        sys.exit(1)
+
+def testall(list, recursive, toplevel):
+    import sys
+    import os
+    for filename in list:
+        if os.path.isdir(filename):
+            print(filename + '/:', end=' ')
+            if recursive or toplevel:
+                print('recursing down:')
+                import glob
+                names = glob.glob(os.path.join(filename, '*'))
+                testall(names, recursive, 0)
+            else:
+                print('*** directory (use -r) ***')
+        else:
+            print(filename + ':', end=' ')
+            sys.stdout.flush()
+            try:
+                print(what(filename))
+            except OSError:
+                print('*** not found ***')
+
+if __name__ == '__main__':
+    test()

tests/snippets/property.py

@@ -59,7 +59,11 @@ with assertRaises(AttributeError):
 with assertRaises(TypeError):
     property.__new__(object)
 
-# assert p.__doc__ is None
+assert p.__doc__ is None
+
+# Test property instance __doc__ attribute:
+p.__doc__ = '222'
+assert p.__doc__ == '222'
 
 
 p1 = property("a", "b", "c")

vm/src/obj/objproperty.rs

@@ -1,7 +1,6 @@
 /*! Python `property` descriptor class.
 
 */
-
 use crate::function::{IntoPyNativeFunc, OptionalArg, PyFuncArgs};
 use crate::obj::objtype::PyClassRef;
 use crate::pyobject::{
@@ -9,6 +8,7 @@ use crate::pyobject::{
     TypeProtocol,
 };
 use crate::vm::VirtualMachine;
+use std::cell::RefCell;
 
 // Read-only property, doesn't have __set__ or __delete__
 #[pyclass]
@@ -80,7 +80,7 @@ pub struct PyProperty {
     getter: Option<PyObjectRef>,
     setter: Option<PyObjectRef>,
     deleter: Option<PyObjectRef>,
-    doc: Option<PyObjectRef>,
+    doc: RefCell<Option<PyObjectRef>>,
 }
 
 impl PyValue for PyProperty {
@@ -107,20 +107,14 @@ impl PyProperty {
         );
 
         fn into_option(vm: &VirtualMachine, arg: Option<&PyObjectRef>) -> Option<PyObjectRef> {
-            arg.and_then(|arg| {
-                if vm.ctx.none().is(arg) {
-                    None
-                } else {
-                    Some(arg.clone())
-                }
-            })
+            arg.and_then(|arg| py_none_to_option(vm, arg))
         }
 
         PyProperty {
             getter: into_option(vm, fget),
             setter: into_option(vm, fset),
             deleter: into_option(vm, fdel),
-            doc: into_option(vm, doc),
+            doc: RefCell::new(into_option(vm, doc)),
         }
         .into_ref_with_type(vm, cls)
     }
@@ -189,6 +183,15 @@ impl PyProperty {
         self.deleter.clone()
     }
 
+    fn doc_getter(&self, _vm: &VirtualMachine) -> Option<PyObjectRef> {
+        self.doc.borrow().clone()
+    }
+
+    fn doc_setter(&self, value: PyObjectRef, vm: &VirtualMachine) -> PyResult {
+        self.doc.replace(py_none_to_option(vm, &value));
+        Ok(vm.get_none())
+    }
+
     // Python builder functions
 
     #[pymethod]
@@ -201,7 +204,7 @@ impl PyProperty {
             getter: getter.or_else(|| zelf.getter.clone()),
             setter: zelf.setter.clone(),
             deleter: zelf.deleter.clone(),
-            doc: None,
+            doc: RefCell::new(None),
         }
         .into_ref_with_type(vm, TypeProtocol::class(&zelf))
     }
@@ -216,7 +219,7 @@ impl PyProperty {
             getter: zelf.getter.clone(),
             setter: setter.or_else(|| zelf.setter.clone()),
             deleter: zelf.deleter.clone(),
-            doc: None,
+            doc: RefCell::new(None),
         }
         .into_ref_with_type(vm, TypeProtocol::class(&zelf))
     }
@@ -231,12 +234,21 @@ impl PyProperty {
             getter: zelf.getter.clone(),
             setter: zelf.setter.clone(),
             deleter: deleter.or_else(|| zelf.deleter.clone()),
-            doc: None,
+            doc: RefCell::new(None),
         }
         .into_ref_with_type(vm, TypeProtocol::class(&zelf))
     }
 }
 
+/// Take a python object and turn it into an option object, where python None maps to rust None.
+fn py_none_to_option(vm: &VirtualMachine, value: &PyObjectRef) -> Option<PyObjectRef> {
+    if vm.ctx.none().is(value) {
+        None
+    } else {
+        Some(value.clone())
+    }
+}
+
 pub struct PropertyBuilder<'a> {
     ctx: &'a PyContext,
     getter: Option<PyObjectRef>,
@@ -276,7 +288,7 @@ impl<'a> PropertyBuilder<'a> {
                 getter: self.getter.clone(),
                 setter: self.setter.clone(),
                 deleter: None,
-                doc: None,
+                doc: RefCell::new(None),
             };
 
             PyObject::new(payload, self.ctx.property_type(), None)
@@ -295,4 +307,14 @@ impl<'a> PropertyBuilder<'a> {
 pub fn init(context: &PyContext) {
     PyReadOnlyProperty::extend_class(context, &context.readonly_property_type);
     PyProperty::extend_class(context, &context.property_type);
+
+    // This is a bit unfortunate, but this instance attribute overlaps with the
+    // class __doc__ string..
+    extend_class!(context, &context.property_type, {
+        "__doc__" =>
+        PropertyBuilder::new(context)
+            .add_getter(PyProperty::doc_getter)
+            .add_setter(PyProperty::doc_setter)
+            .create(),
+    });
 }