Personal Computer World 2009 February/PCWFEB09.iso/Software/Linux/Kubuntu 8.10/kubuntu-8.10-desktop-i386.iso/casper/filesystem.squashfs/usr/lib/python2.5/wave.pyc

Python Compiled Bytecode | 2008-10-29 | 19KB | 569 lines

# Source Generated with Decompyle++
# File: in.pyc (Python 2.5)

"""Stuff to parse WAVE files.

Usage.

Reading WAVE files:
      f = wave.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().
When the setpos() and rewind() methods are 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 linear samples)
      getcompname()   -- returns human-readable version of
                         compression type ('not compressed' linear samples)
      getparams()     -- returns a tuple consisting of all of the
                         above in the above order
      getmarkers()    -- returns None (for compatibility with the
                         aifc module)
      getmark(id)     -- raises an error since the mark does not
                         exist (for compatibility with the aifc module)
      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() and the position given to setpos()
are 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 WAVE files:
      f = wave.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:
      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
      tell()          -- return current position in output file
      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('') or
close() to patch up the sizes in the header.
The close() method is called automatically when the class instance
is destroyed.
"""
import __builtin__
__all__ = [
    'open',
    'openfp',
    'Error']

class Error(Exception):
    pass

WAVE_FORMAT_PCM = 1
_array_fmts = (None, 'b', 'h', None, 'l')
import struct
if struct.pack('h', 1) == '\x00\x01':
    big_endian = 1
else:
    big_endian = 0
from chunk import Chunk

class Wave_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
    _soundpos -- the position in the audio stream
              available through the tell() method, set through the
              setpos() method

    These variables are used internally only:
    _fmt_chunk_read -- 1 iff the FMT chunk has been read
    _data_seek_needed -- 1 iff positioned correctly in audio
              file for readframes()
    _data_chunk -- instantiation of a chunk class for the DATA chunk
    _framesize -- size of one frame in the file
    """

    def initfp(self, file):
        self._convert = None
        self._soundpos = 0
        self._file = Chunk(file, bigendian = 0)
        if self._file.getname() != 'RIFF':
            raise Error, 'file does not start with RIFF id'

        if self._file.read(4) != 'WAVE':
            raise Error, 'not a WAVE file'

        self._fmt_chunk_read = 0
        self._data_chunk = None
        while None:
            self._data_seek_needed = 1

            try:
                chunk = Chunk(self._file, bigendian = 0)
            except EOFError:
                break

            chunkname = chunk.getname()
            if chunkname == 'fmt ':
                self._read_fmt_chunk(chunk)
                self._fmt_chunk_read = 1
            elif chunkname == 'data':
                if not self._fmt_chunk_read:
                    raise Error, 'data chunk before fmt chunk'

                self._data_chunk = chunk
                self._nframes = chunk.chunksize // self._framesize
                self._data_seek_needed = 0
                break

            continue
            if not (self._fmt_chunk_read) or not (self._data_chunk):
                raise Error, 'fmt chunk and/or data chunk missing'



    def __init__(self, f):
        self._i_opened_the_file = None
        if isinstance(f, basestring):
            f = __builtin__.open(f, 'rb')
            self._i_opened_the_file = f


        try:
            self.initfp(f)
        except:
            if self._i_opened_the_file:
                f.close()

            raise



    def __del__(self):
        self.close()


    def getfp(self):
        return self._file


    def rewind(self):
        self._data_seek_needed = 1
        self._soundpos = 0


    def close(self):
        if self._i_opened_the_file:
            self._i_opened_the_file.close()
            self._i_opened_the_file = None

        self._file = None


    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 getparams(self):
        return (self.getnchannels(), self.getsampwidth(), self.getframerate(), self.getnframes(), self.getcomptype(), self.getcompname())


    def getmarkers(self):
        pass


    def getmark(self, id):
        raise Error, 'no marks'


    def setpos(self, pos):
        if pos < 0 or pos > self._nframes:
            raise Error, 'position not in range'

        self._soundpos = pos
        self._data_seek_needed = 1


    def readframes(self, nframes):
        if self._data_seek_needed:
            self._data_chunk.seek(0, 0)
            pos = self._soundpos * self._framesize
            if pos:
                self._data_chunk.seek(pos, 0)

            self._data_seek_needed = 0

        if nframes == 0:
            return ''

        if self._sampwidth > 1 and big_endian:
            import array as array
            chunk = self._data_chunk
            data = array.array(_array_fmts[self._sampwidth])
            nitems = nframes * self._nchannels
            if nitems * self._sampwidth > chunk.chunksize - chunk.size_read:
                nitems = (chunk.chunksize - chunk.size_read) / self._sampwidth

            data.fromfile(chunk.file.file, nitems)
            chunk.size_read = chunk.size_read + nitems * self._sampwidth
            chunk = chunk.file
            chunk.size_read = chunk.size_read + nitems * self._sampwidth
            data.byteswap()
            data = data.tostring()
        else:
            data = self._data_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


    def _read_fmt_chunk(self, chunk):
        (wFormatTag, self._nchannels, self._framerate, dwAvgBytesPerSec, wBlockAlign) = struct.unpack('<hhllh', chunk.read(14))
        if wFormatTag == WAVE_FORMAT_PCM:
            sampwidth = struct.unpack('<h', chunk.read(2))[0]
            self._sampwidth = (sampwidth + 7) // 8
        else:
            raise Error, 'unknown format: %r' % (wFormatTag,)
        self._framesize = self._nchannels * self._sampwidth
        self._comptype = 'NONE'
        self._compname = 'not compressed'



class Wave_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

    These variables are used internally only:
    _datalength -- the size of the audio samples written to the header
    _nframeswritten -- the number of frames actually written
    _datawritten -- the size of the audio samples actually written
    """

    def __init__(self, f):
        self._i_opened_the_file = None
        if isinstance(f, basestring):
            f = __builtin__.open(f, 'wb')
            self._i_opened_the_file = f


        try:
            self.initfp(f)
        except:
            if self._i_opened_the_file:
                f.close()

            raise



    def initfp(self, file):
        self._file = file
        self._convert = None
        self._nchannels = 0
        self._sampwidth = 0
        self._framerate = 0
        self._nframes = 0
        self._nframeswritten = 0
        self._datawritten = 0
        self._datalength = 0


    def __del__(self):
        self.close()


    def setnchannels(self, nchannels):
        if self._datawritten:
            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._datawritten:
            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._datawritten:
            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._datawritten:
            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._datawritten:
            raise Error, 'cannot change parameters after starting to write'

        if comptype not in ('NONE',):
            raise Error, 'unsupported compression type'

        self._comptype = comptype
        self._compname = compname


    def getcomptype(self):
        return self._comptype


    def getcompname(self):
        return self._compname


    def setparams(self, .1):
        (nchannels, sampwidth, framerate, nframes, comptype, compname) = .1
        if self._datawritten:
            raise Error, 'cannot change parameters after starting to write'

        self.setnchannels(nchannels)
        self.setsampwidth(sampwidth)
        self.setframerate(framerate)
        self.setnframes(nframes)
        self.setcomptype(comptype, compname)


    def getparams(self):
        if not (self._nchannels) and not (self._sampwidth) or not (self._framerate):
            raise Error, 'not all parameters set'

        return (self._nchannels, self._sampwidth, self._framerate, self._nframes, self._comptype, self._compname)


    def setmark(self, id, pos, name):
        raise Error, 'setmark() not supported'


    def getmark(self, id):
        raise Error, 'no marks'


    def getmarkers(self):
        pass


    def tell(self):
        return self._nframeswritten


    def writeframesraw(self, data):
        self._ensure_header_written(len(data))
        nframes = len(data) // self._sampwidth * self._nchannels
        if self._convert:
            data = self._convert(data)

        if self._sampwidth > 1 and big_endian:
            import array
            data = array.array(_array_fmts[self._sampwidth], data)
            data.byteswap()
            data.tofile(self._file)
            self._datawritten = self._datawritten + len(data) * self._sampwidth
        else:
            self._file.write(data)
            self._datawritten = self._datawritten + len(data)
        self._nframeswritten = self._nframeswritten + nframes


    def writeframes(self, data):
        self.writeframesraw(data)
        if self._datalength != self._datawritten:
            self._patchheader()



    def close(self):
        if self._file:
            self._ensure_header_written(0)
            if self._datalength != self._datawritten:
                self._patchheader()

            self._file.flush()
            self._file = None

        if self._i_opened_the_file:
            self._i_opened_the_file.close()
            self._i_opened_the_file = None



    def _ensure_header_written(self, datasize):
        if not self._datawritten:
            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 _write_header(self, initlength):
        self._file.write('RIFF')
        if not self._nframes:
            self._nframes = initlength / self._nchannels * self._sampwidth

        self._datalength = self._nframes * self._nchannels * self._sampwidth
        self._form_length_pos = self._file.tell()
        self._file.write(struct.pack('<l4s4slhhllhh4s', 36 + self._datalength, 'WAVE', 'fmt ', 16, WAVE_FORMAT_PCM, self._nchannels, self._framerate, self._nchannels * self._framerate * self._sampwidth, self._nchannels * self._sampwidth, self._sampwidth * 8, 'data'))
        self._data_length_pos = self._file.tell()
        self._file.write(struct.pack('<l', self._datalength))


    def _patchheader(self):
        if self._datawritten == self._datalength:
            return None

        curpos = self._file.tell()
        self._file.seek(self._form_length_pos, 0)
        self._file.write(struct.pack('<l', 36 + self._datawritten))
        self._file.seek(self._data_length_pos, 0)
        self._file.write(struct.pack('<l', self._datawritten))
        self._file.seek(curpos, 0)
        self._datalength = self._datawritten



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 Wave_read(f)
    elif mode in ('w', 'wb'):
        return Wave_write(f)
    else:
        raise Error, "mode must be 'r', 'rb', 'w', or 'wb'"

openfp = open