104 lines
4.2 KiB
Text
Executable file
104 lines
4.2 KiB
Text
Executable file
Interface to CD-ROM player.
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This module implements an interface to the built-in cd module. The
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intention is to provide a more user-friendly interface than the
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built-in module.
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The module defines a class Readcd with several methods. The
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initialization of the class will try to open the CD player. This
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means that initialization will fail if the CD player is already in
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use. A RuntimeError will be raised by the cd module in that case.
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The way to work with this module is as follows. The user specifies
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the parts of the CD that are to be read and he specifies callback
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functions which are to be called by the system. At some point he can
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tell the system to play. The specified parts of the CD will then be
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read and the callbacks will be called.
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Initialization.
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===============
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r = readcd.Readcd([cd-player [, mode]])
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The optional arguments are the name of the CD device and the mode.
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When "mode" is not specified, it defaults to 'r' (which is the only
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possible value); when "cd-player" also isn't specified, it defaults
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to "None" which indicates the default CD player.
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Methods.
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========
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eject() -- Eject the CD from the player.
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reset() -- Reset the list of data stretches to be played.
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appendtrack(track) -- Append the specified track to the list of music
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stretches.
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appendstretch(first, last) -- Append the stretch from "first" to "last"
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to the list of music stretches. Both "first" and "last" can be in one
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of four forms. "None": for "first", the beginning of the CD, for
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"last" the end of the CD; a single integer: a track number--playing
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starts at the beginning of the track or ends at the end of the
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specified track; a three-tuple: the absolute time from the start of
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the CD in minutes, seconds, frames; a four-tuple: track number and
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relative time within the track in minutes, seconds, frames.
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settracks(tracklist) -- The argument is a list of integers. The list
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of stretches is set to argument list. The old list is discarded.
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setcallback(type, func, arg) -- Set a callback function for "type".
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The function will be called as func(arg, type, data) where "arg" is
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the third argument of setcallback, "type" is the type of callback,
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"data" is type-dependent data. See the CDsetcallback(3) manual page
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for more information. The possible "type" arguments are defined in
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the CD module.
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removecallback(type) -- Remove the callback for "type".
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gettrackinfo([tracklist]) -- Return a list of tuples. Each tuple
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consists of start and length information of a track. The start and
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length information consist of three-tuples with minutes, seconds and
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frames. The optional tracklist argument gives a list of interesting
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track numbers. If no tracklist is specified, information about all
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tracks is returned.
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getstatus() -- Return the status information of the CD.
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play() -- Play the preprogrammed stretches of music from the CD. When
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nothing was programmed, the whole CD is played.
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Specifying stretches.
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=====================
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There are three methods available to specify a stretch of music to be
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played. The easiest way is to use "settracklist(tracklist)" with which
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a list of tracks can be specified. "settracklist(tracklist)" is
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equivalent to the sequence
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reset()
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for track in tracklist:
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appendtrack(track)
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The next method is "appendtrack(track)" with which a whole track can be
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added to the list of music to be played. "appendtrack(track)" is
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equivalent to "appendstretch(track, track)".
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The most complete method is "appendstretch(first, last)". Using this
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method, it is possible to specify any stretch of music.
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When two consecutive tracks are played, it is possible to choose
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whether the pause that may be between the tracks is played as well or
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whether the pause should be skipped. When the end of a stretch is
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specified using a track number and the next stretch starts at the
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beginning of the following track and that was also specified using the
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track number (that is, both were specified as integers, not as tuples),
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the pause is played. When either value was specified using absolute
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time or track-relative time (that is, as three-tuple or as
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four-tuple), the pause will not be played.
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Errors.
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=======
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When an error occurs, an exception will be raised. Depending on where
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the error occurs, the exception may either be "readcd.Error" or
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"RuntimeError".
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