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- Committer: Bazaar Package Importer
- Author(s): Miriam Ruiz, Miriam Ruiz, Mario Bonino, Jon Dowland, Ansgar Burchardt
- Date: 2008-06-07 16:43:18 UTC
- mfrom: (1.1.2 upstream)
- mto: This revision was merged to the branch mainline in revision 6.
- Revision ID: james.westby@ubuntu.com-20080607164318-spq0cnpt8mjhg1pj
[ Miriam Ruiz ]
* New Upstream Release (Closes: #453132)
* Removed unneeded patches
* Added packages to build deps:
+ libtool
+ portaudio19-dev | portaudio-dev
+ libboost-dev, libboost-thread-dev, libboost-serialization-dev
+ libboost-program-options-dev, libboost-regex-dev
* Moved shared objects to private directory: /usr/lib/ultraster-ng
* Added rpath to binaries to search for shared objects in the private dir
* Uses ultrastar-ng-gstreamer as default, instead of ultrastar-ng-xine,
since there are significantly less issues with GStreamer.
* Added patch to fix upstream desktop file
* Added -Wl,-as-needed to LDFLAGS
* Replaced fftw3-dev by libfftw3-dev in build dependencies.
* Standards-Version upgraded to 3.7.3
[ Mario Bonino ]
* Fixed data/Makefile.am to install .desktop file and icon
[ Jon Dowland ]
* add Homepage: control field to source stanza
* fix a bashism in debian/rules (Closes: #478634)
[ Ansgar Burchardt ]
* debian/control: Change XS-Vcs-* to Vcs-*
* Remove Homepage semi-field from description
* New Upstream Release (Closes: #453132)
* Removed unneeded patches
* Added packages to build deps:
+ libtool
+ portaudio19-dev | portaudio-dev
+ libboost-dev, libboost-thread-dev, libboost-serialization-dev
+ libboost-program-options-dev, libboost-regex-dev
* Moved shared objects to private directory: /usr/lib/ultraster-ng
* Added rpath to binaries to search for shared objects in the private dir
* Uses ultrastar-ng-gstreamer as default, instead of ultrastar-ng-xine,
since there are significantly less issues with GStreamer.
* Added patch to fix upstream desktop file
* Added -Wl,-as-needed to LDFLAGS
* Replaced fftw3-dev by libfftw3-dev in build dependencies.
* Standards-Version upgraded to 3.7.3
[ Mario Bonino ]
* Fixed data/Makefile.am to install .desktop file and icon
[ Jon Dowland ]
* add Homepage: control field to source stanza
* fix a bashism in debian/rules (Closes: #478634)
[ Ansgar Burchardt ]
* debian/control: Change XS-Vcs-* to Vcs-*
* Remove Homepage semi-field from description
- files added:
- audio
- audio/alsa
- files removed:
- debian/patches/check_sdl_init.patch
- files modified:
- AUTHORS
added
removed
audio/alsa/alsa.hpp
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#ifndef ALSA_HPP_INCLUDED
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#define ALSA_HPP_INCLUDED
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/**
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@file alsa.hpp
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@brief An experimental low-level C++ API to ALSA.
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@version 0.4
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@author Lasse Kärkkäinen <tronic>
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@license GNU LGPL 2.1 or later
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This is a header-only C++ wrapper for the ALSA library. This means that you do
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not need to add any new binary files to your build and you will only need to
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link with -lasound, as if you were using the C API directly. GCC will probably
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optimize all of the wrapper overhead away in any case, leaving you with a safer
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and easier API to ALSA, but leaving your binaries just as if you had used C.
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The library is designed to be very closely related to the C API, so that you
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can still see what is going on under the hood, and also so that porting existing
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applications to it is trivial. The interoperatibility between C and C++ APIs is
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is a major design goal. What this means is that you can freely mix C and C++ API
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calls with no problems.
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Usage example:
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alsa::pcm alsa_pcm; // Create a PCM object (defaults to playback and mode = 0)
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The above creates an equivalent for the snd_pcm_t*, which is what you need to
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play or record anything. Make sure that the alsa_pcm object stays alive as long
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as you need it (and preferrably not longer) by putting it inside a suitable
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class or even inside the main() function. The object cannot be copied, but you
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can pass references to it to other objects or functions.
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The alsa_pcm also automatically converts into snd_pcm_t* as required, so you can
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use it as an argument for the C API functions.
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Next you'll need to configure it:
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unsigned int rate = 44100;
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unsigned int period;
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alsa::hw_config(alsa_pcm) // Create a new config space
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.set(SND_PCM_ACCESS_RW_INTERLEAVED)
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.set(SND_PCM_FORMAT_S16_LE)
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.rate_near(rate)
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.channels(1)
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.period_size_first(period) // Get the smallest available period size
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.commit(); // Apply the config to the PCM
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alsa::hw_config(pcm) constructs a new config space, using the current settings
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from the PCM, if available, or the "any" space, if not set yet. The any space
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contains all available hardware configurations and you have to narrow it down
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to exactly one option by setting some parameters. Trying to narrow it too much
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(by asking an amount of channels that is not available, for example) causes a
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failure.
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In case of failure, an alsa::error is thrown. When this happens, the commit part
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never gets executed and thus the result is not stored to alsa_pcm and the
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failed operation will have no effect (even to the temporary hw_config object,
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which gets destroyed when the exception flies). However, all the operations
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already performed successfully remain in effect.
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The rate_near functions behaves like the C API *_near functions
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do: they take the preferred value as an argument and then they modify the
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argument, returning the actual rate. For example, if your sound card only
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supports 48000 Hz, rate will be set to that on that call, even if some later
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part, such as setting the number of channels, fails.
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In the example above, a temporary object of type alsa::hw_config was used, but
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you can also create a variable of it, should you need to test something in
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between, or if you want to call the C API functions directly (hw_config
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converts automatically into hw_params, which converts into snd_hw_params_t*).
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For this, you may use a block like this:
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{
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alsa::hw_config hw(alsa_pcm);
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hw.set(SND_ACCESS_(SND_PCM_ACCESS_MMAP_INTERLEAVED);
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hw.set(SND_PCM_FORMAT_FLOAT_BE);
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if (!snd_pcm_hw_params_is_full_duplex(hw)) hw.channels(2);
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hw.commit();
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}
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(anyone got a better example?)
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Software configuration works in the same way, using alsa::sw_config, just the
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parameters to be adjusted are different.
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When constructed, both sw_config and hw_config try to load config from the given
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PCM. If that fails, sw_config throws, but hw_config still tries loading the any
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space. Alternatively, you may supply a snd_pcm_hw/sw_params_t const* as a second
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argument for the constructor to get a copy of the contents of that that instead.
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The contents may be loaded (overwrites the old contents) with these functions:
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.any() Get the "any" configuration (hw_config only)
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.current() Get the currently active configuration from PCM
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Once finished with the changes, you should call:
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.commit() Store current config space to the PCM
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For enum values SND_PCM_*, you may use the following functions:
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.get(var) Get the current setting into the given variable
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.set(val) Set the value requested (also supports masks)
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.enum_test(val) The same as .set, except that it does not set anything
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.enum_first(var) Set the first available option, store the selection in var
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.enum_last(var) Set the last available option, store the selection in var
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The parameter to manipulate is chosen based on the argument type. The enum_*
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functions and masks are only available for hardware parameters, not for
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sw_param.
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For integer values (times, sizes, counts), these functions are available:
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.get_X(var) Get the current setting into the given variable
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.X(val) Set the value requested
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For ranges, the following can also be used:
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.get_X_min(var) Get the smallest available value into var
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.get_X_max(var) Get the largest available value into var
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.X_min(var) Remove all values smaller than var and store the new
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smallest value into var.
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.X_max(var) Remove all values larger than var, store new max in var.
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.X_minmax(v1, v2) Limit to [v1, v2], store new range in v1, v2.
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.X_near(var) Set the closest available value and store it in var
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.X_first(var) Set the first available option, store the selection in var
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.X_last(var) Set the last available option, store the selection in var
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For booleans, these functions are available:
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.get_X(var) Get the current setting (var must be unsigned int or bool)
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.set_X(val) Set the value (val can be anything that converts into bool)
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Replace X with the name of the parameter that you want to set. Consult the ALSA
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C library reference for available options. All functions that modify their
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arguments require the same type as is used in the C API (often unsigned int or
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snd_pcm_uframes_t). The only exception is with bool types, where both bool and
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unsigned int are accepted.
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For those ranged parameters that support the dir argument (see ALSA docs), the
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default value is always 0 when writing and NULL (none) when reading. You may
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supply the preferred dir value or variable as the second argument and then the
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value will be used or the result will be stored in the variable supplied.
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For example, the following calls are equivalent:
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snd_pcm_hw_params_set_format(pcm, hw, SND_PCM_FORMAT_FLOAT_LE)
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<=> hw.set(SND_PCM_FORMAT_FLOAT_LE)
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snd_pcm_hw_params_set_rate_resample(pcm, hw, 1) <=> hw.rate_resample(true)
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snd_pcm_hw_params_set_channels_near(pcm, hw, &num) <=> hw.channels_near(num)
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snd_pcm_hw_params_get_rate(hw, &rate, NULL) <=> hw.get_rate(rate)
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snd_pcm_hw_params_get_rate(hw, &rate, &dir) <=> hw.get_rate(rate, dir)
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... except for the fact that the C++ versions also check the return values and
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throw alsa::error if anything goes wrong. alsa::error inherits from
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std::runtime_error and thus eventually from std::exception, so you can catch
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pretty much everything by catching that somewhere in your code:
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try {
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// do everything here
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} catch (std::exception& e) {
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std::cerr << "FATAL ERROR: " << e.what() << std::endl;
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}
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However, recent versions of glibc seem to be handling uncaught exceptions quite
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nicely, so even without a try-catch you may get a nice printout in your console:
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terminate called after throwing an instance of 'alsa::error'
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what(): ALSA snd_pcm_hw_params_set_channels failed: Invalid argument
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Aborted
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If you need to know the error code, you may call e.code() after catching
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alsa::error& e.
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When you call the C API functions directly, the ALSA_CHECKED macro may prove to
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be useful. It is used internally by the library for testing errors and throwing
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exceptions when calling the C functions. It will throw alsa::error with a
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description of the error if the function returns a negative value.
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The macro is well-behaving, as it only calls an internal helper function,
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evaluating the arguments given exactly once.
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Usage: ALSA_CHECKED(snd_pcm_whatever, (arg1, arg2, arg2));
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Note: a comma between function name and arguments.
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The return value can also still be used (will return only >= 0):
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For MMAP transfers, another RAII wrapper, alsa::mmap, is provided.
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Usage:
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// First we need to call avail_update (storing the return value is optional)
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snd_pcm_uframes_t count = ALSA_CHECKED(snd_pcm_avail_update, (pcm));
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alsa::mmap mmap(pcm, 256) // Begin MMAP transfer, request 256 frames
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// Process the audio (mmap.frames frames of it, accessible via mmap.areas,
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// starting at offset mmap.offset) and then let mmap go out of scope, which will
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// end the transfer. If you didn't process all available frames, set the number
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// of frames processed to mmap.frames before the object goes out of scope.
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As usual, the constructor will throw alsa::error in case of error.
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In case you really want to get low-level, alsa::hw_params and alsa::sw_params
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are offered. These only contain the corresponding snd_pcm_*_params_t, but they
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allocate and free memory automatically and they can also properly copy the
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struct contents when they get copied. Be aware that the structure contents are
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not initialized during construction, so you have to initialize it yourself (just
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like with the C API). They are used internally by hw_config and sw_config and
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normally it should be better to use these instead of dealing directly with the
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params.
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**/
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#include <alsa/asoundlib.h>
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#include <stdexcept>
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#include <string>
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/**
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* A macro that executes func with the given args and tests for errors.
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* Examples of use:
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* ALSA_CHECKED(snd_pcm_recover, (pcm, e.code(), 0));
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* snd_pcm_uframes_t count = ALSA_CHECKED(snd_pcm_avail_update, (pcm));
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* @param func the function name
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* @param args arguments in parenthesis
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* @return the return value of the function
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* @throws alsa::error if the return value is smaller than zero.
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**/
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#define ALSA_CHECKED(func, args) alsa::internal::check(func args, #func)
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namespace alsa {
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/** @short Exception class **/
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class error: public std::runtime_error {
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int err;
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public:
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error(std::string const& function, int err): std::runtime_error("ALSA " + function + " failed: " + std::string(snd_strerror(err))), err(err) {}
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int code() const { return err; }
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};
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namespace internal {
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/** For internal use only: a function used by the macro ALSA_CHECKED **/
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template<typename T> T check(T ret, char const* funcname) {
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if (ret < 0) throw error(funcname, ret);
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return ret;
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}
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/**
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* @short FOR INTERNAL USE ONLY. A utility class similar to
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* boost::noncopyable, duplicated here in order to avoid
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* a dependency on the Boost library.
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**/
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class noncopyable {
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protected:
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noncopyable() {}
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~noncopyable() {}
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private:
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noncopyable(noncopyable const&);
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noncopyable const& operator=(noncopyable const&);
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};
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}
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/**
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* @short A minimal RAII wrapper for ALSA PCM.
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* Automatically converts into snd_pcm_t* as needed, so the ALSA C API
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* can be used directly with this.
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**/
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class pcm: internal::noncopyable {
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snd_pcm_t* handle;
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public:
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pcm(char const* device = "default", snd_pcm_stream_t stream = SND_PCM_STREAM_PLAYBACK, int mode = 0) {
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ALSA_CHECKED(snd_pcm_open, (&handle, device, stream, mode));
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}
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~pcm() { snd_pcm_close(handle); }
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operator snd_pcm_t*() { return handle; }
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operator snd_pcm_t const*() const { return handle; }
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};
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// RAII wrapper for snd_pcm_hw/sw_params_t types.
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#define ALSA_HPP_PARAMWRAPPER(type) \
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class type##_params {\
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snd_pcm_##type##_params_t* handle;\
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void init() { ALSA_CHECKED(snd_pcm_##type##_params_malloc, (&handle)); }\
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public:\
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type##_params() { init(); }\
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~type##_params() { snd_pcm_##type##_params_free(handle); }\
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type##_params(type##_params const& orig) { init(); *this = orig; }\
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type##_params(snd_pcm_##type##_params_t const* orig) { init(); *this = orig; }\
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type##_params& operator=(snd_pcm_##type##_params_t const* params) {\
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if (handle != params) snd_pcm_##type##_params_copy(handle, params);\
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return *this;\
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}\
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operator snd_pcm_##type##_params_t*() { return handle; }\
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operator snd_pcm_##type##_params_t const*() const { return handle; }\
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};
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ALSA_HPP_PARAMWRAPPER(hw)
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ALSA_HPP_PARAMWRAPPER(sw)
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#undef ALSA_HPP_PARAMWRAPPER
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// Various helper macros used for generating code for hw_config and sw_config
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#define ALSA_HPP_FUNC(name, suffix) ALSA_HPP_TEMPLATE(& name(), suffix, (pcm, params))
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#define ALSA_HPP_VARGET(name, type) \
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ALSA_HPP_TEMPLATE(& get_##name(type& val), _get_##name, (params, &val))\
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ALSA_HPP_TEMPLATE(const& get_##name(type& val) const, _get_##name, (params, &val))
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#define ALSA_HPP_VAR(name, type) ALSA_HPP_VARGET(name, type)\
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ALSA_HPP_TEMPLATE(& name(type val), _set_##name, (pcm, params, val))
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#define ALSA_HPP_ENUMVARMINIMAL(name) \
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ALSA_HPP_TEMPLATE(& get(snd_pcm_##name##_t& name), _get_##name, (params, &name))\
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ALSA_HPP_TEMPLATE(const& get(snd_pcm_##name##_t& name) const, _get_##name, (params, &name))\
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ALSA_HPP_TEMPLATE(& set(snd_pcm_##name##_t name), _set_##name, (pcm, params, name))
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#define ALSA_HPP_ENUMVAR(name) ALSA_HPP_ENUMVARMINIMAL(name)\
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ALSA_HPP_TEMPLATE(& enum_test(snd_pcm_##name##_t name), _test_##name, (pcm, params, name))\
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ALSA_HPP_TEMPLATE(& enum_first(snd_pcm_##name##_t& name), _set_##name##_first, (pcm, params, &name))\
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ALSA_HPP_TEMPLATE(& enum_last(snd_pcm_##name##_t& name), _set_##name##_last, (pcm, params, &name))\
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ALSA_HPP_TEMPLATE(& set(snd_pcm_##name##_mask_t* mask), _set_##name##_mask, (pcm, params, mask))
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#define ALSA_HPP_BOOLVAR(name) \
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ALSA_HPP_CLASS& get_##name(bool& val) { unsigned int tmp; get_##name(tmp); val = tmp; return *this; }\
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/*ALSA_HPP_CLASS const& get_##name(bool& val) const { unsigned int tmp; get_##name(tmp); val = tmp; return *this; }*/\
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ALSA_HPP_TEMPLATE(& get_##name(unsigned int& val), _get_##name, (pcm, params, &val))\
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/*ALSA_HPP_TEMPLATE(const& get_##name(unsigned int& val) const, _get_##name, (pcm, params, &val))*/\
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ALSA_HPP_TEMPLATE(& name(bool val = true), _set_##name, (pcm, params, val))
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#define ALSA_HPP_RANGEVAR(name, type) ALSA_HPP_VAR(name, type)\
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ALSA_HPP_TEMPLATE(& get_##name##_min(type& min), _get_##name##_min, (params, &min))\
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ALSA_HPP_TEMPLATE(const& get_##name##_min(type& min) const, _get_##name##_min, (params, &min))\
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ALSA_HPP_TEMPLATE(& get_##name##_max(type& max), _get_##name##_max, (params, &max))\
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ALSA_HPP_TEMPLATE(const& get_##name##_max(type& max) const, _get_##name##_max, (params, &max))\
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ALSA_HPP_TEMPLATE(& name##_min(type& min), _set_##name##_min, (pcm, params, &min))\
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ALSA_HPP_TEMPLATE(& name##_max(type& max), _set_##name##_max, (pcm, params, &max))\
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ALSA_HPP_TEMPLATE(& name##_minmax(type& min, type& max), _set_##name##_minmax, (pcm, params, &min, &max))\
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ALSA_HPP_TEMPLATE(& name##_near(type& val), _set_##name##_near, (pcm, params, &val))\
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ALSA_HPP_TEMPLATE(& name##_first(type& val), _set_##name##_first, (pcm, params, &val))\
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ALSA_HPP_TEMPLATE(& name##_last(type& val), _set_##name##_last, (pcm, params, &val))
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#define ALSA_HPP_RANGEVARDIR(name, type) \
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ALSA_HPP_TEMPLATE(& get_##name(type& val), _get_##name, (params, &val, NULL))\
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ALSA_HPP_TEMPLATE(const& get_##name(type& val) const, _get_##name, (params, &val, NULL))\
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ALSA_HPP_TEMPLATE(& get_##name(type& val, int& dir), _get_##name, (params, &val, &dir))\
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ALSA_HPP_TEMPLATE(const& get_##name(type& val, int& dir) const, _get_##name, (params, &val, &dir))\
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ALSA_HPP_TEMPLATE(& get_##name##_min(type& min), _get_##name##_min, (params, &min, NULL))\
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ALSA_HPP_TEMPLATE(const& get_##name##_min(type& min) const, _get_##name##_min, (params, &min, NULL))\
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ALSA_HPP_TEMPLATE(& get_##name##_min(type& min, int& dir), _get_##name##_min, (params, &min, &dir))\
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ALSA_HPP_TEMPLATE(const& get_##name##_min(type& min, int& dir) const, _get_##name##_min, (params, &min, &dir))\
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ALSA_HPP_TEMPLATE(& get_##name##_max(type& max), _get_##name##_max, (params, &max, NULL))\
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ALSA_HPP_TEMPLATE(const& get_##name##_max(type& max) const, _get_##name##_max, (params, &max, NULL))\
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ALSA_HPP_TEMPLATE(& get_##name##_max(type& max, int& dir), _get_##name##_max, (params, &max, &dir))\
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ALSA_HPP_TEMPLATE(const& get_##name##_max(type& max, int& dir) const, _get_##name##_max, (params, &max, &dir))\
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ALSA_HPP_TEMPLATE(& name(type val, int dir = 0), _set_##name, (pcm, params, val, dir))\
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ALSA_HPP_TEMPLATE(& name##_min(type& min), _set_##name##_min, (pcm, params, &min, NULL))\
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ALSA_HPP_TEMPLATE(& name##_min(type& min, int& dir), _set_##name##_min, (pcm, params, &min, &dir))\
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ALSA_HPP_TEMPLATE(& name##_max(type& max), _set_##name##_max, (pcm, params, &max, NULL))\
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ALSA_HPP_TEMPLATE(& name##_max(type& max, int& dir), _set_##name##_max, (pcm, params, &max, &dir))\
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ALSA_HPP_TEMPLATE(& name##_minmax(type& min, type& max), _set_##name##_minmax, (pcm, params, &min, NULL, &max, NULL))\
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ALSA_HPP_TEMPLATE(& name##_minmax(type& min, int& mindir, type& max, int& maxdir), _set_##name##_minmax, (pcm, params, &min, &mindir, &max, &maxdir))\
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ALSA_HPP_TEMPLATE(& name##_near(type& val), _set_##name##_near, (pcm, params, &val, NULL))\
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ALSA_HPP_TEMPLATE(& name##_near(type& val, int& dir), _set_##name##_near, (pcm, params, &val, &dir))\
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ALSA_HPP_TEMPLATE(& name##_first(type& val), _set_##name##_first, (pcm, params, &val, NULL))\
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ALSA_HPP_TEMPLATE(& name##_first(type& val, int& dir), _set_##name##_first, (pcm, params, &val, &dir))\
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ALSA_HPP_TEMPLATE(& name##_last(type& val), _set_##name##_last, (pcm, params, &val, NULL))\
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ALSA_HPP_TEMPLATE(& name##_last(type& val, int& dir), _set_##name##_last, (pcm, params, &val, &dir))
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/** @short A helper object for modifying hw_params of a PCM. **/
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class hw_config: internal::noncopyable {
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snd_pcm_t* pcm;
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hw_params params;
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public:
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/**
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* Construct a new config object, initialized with the current settings
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* of the PCM or with the "any" configuration space, if there are none.
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**/
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hw_config(snd_pcm_t* pcm): pcm(pcm) {
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try { current(); } catch (std::runtime_error&) { any(); }
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}
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/** Construct a new config object, initialized with a copy from given parameters **/
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hw_config(snd_pcm_t* pcm, snd_pcm_hw_params_t const* params): pcm(pcm), params(params) {}
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operator hw_params&() { return params; }
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operator hw_params const&() const { return params; }
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#define ALSA_HPP_CLASS hw_config
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#define ALSA_HPP_TEMPLATE(proto, suffix, params) ALSA_HPP_CLASS proto { ALSA_CHECKED(snd_pcm_hw_params##suffix, params); return *this; }
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// Load / store functions
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ALSA_HPP_FUNC(commit,)
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ALSA_HPP_FUNC(any, _any)
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ALSA_HPP_FUNC(current, _current)
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// Enum functions
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ALSA_HPP_ENUMVAR(access)
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ALSA_HPP_ENUMVAR(format)
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ALSA_HPP_ENUMVAR(subformat)
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// Bool functions
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ALSA_HPP_BOOLVAR(rate_resample)
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ALSA_HPP_BOOLVAR(export_buffer)
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// Range functions
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ALSA_HPP_RANGEVAR(channels, unsigned int)
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ALSA_HPP_RANGEVAR(buffer_size, snd_pcm_uframes_t)
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// Range functions with direction argument
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ALSA_HPP_RANGEVARDIR(rate, unsigned int)
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ALSA_HPP_RANGEVARDIR(period_time, unsigned int)
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ALSA_HPP_RANGEVARDIR(period_size, snd_pcm_uframes_t)
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ALSA_HPP_RANGEVARDIR(periods, unsigned int)
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ALSA_HPP_RANGEVARDIR(buffer_time, unsigned int)
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ALSA_HPP_RANGEVARDIR(tick_time, unsigned int)
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#undef ALSA_HPP_TEMPLATE
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#undef ALSA_HPP_CLASS
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};
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class sw_config: internal::noncopyable {
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snd_pcm_t* pcm;
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sw_params params;
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public:
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sw_config(snd_pcm_t* pcm): pcm(pcm) { current(); }
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/** Construct a new config object, initialized with a copy from given parameters **/
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sw_config(snd_pcm_t* pcm, snd_pcm_sw_params_t const* params): pcm(pcm), params(params) {}
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operator sw_params&() { return params; }
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operator sw_params const&() const { return params; }
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#define ALSA_HPP_CLASS sw_config
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#define ALSA_HPP_TEMPLATE(proto, suffix, params) ALSA_HPP_CLASS proto { ALSA_CHECKED(snd_pcm_sw_params##suffix, params); return *this; }
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// Load / store functions
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ALSA_HPP_FUNC(commit,)
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ALSA_HPP_FUNC(current, _current)
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// Enum functions
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typedef snd_pcm_tstamp_t snd_pcm_tstamp_mode_t; // Workaround for inconsistent naming in asound
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ALSA_HPP_ENUMVARMINIMAL(tstamp_mode)
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// Simple variable functions
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ALSA_HPP_VAR(sleep_min, unsigned int)
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ALSA_HPP_VAR(avail_min, snd_pcm_uframes_t)
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ALSA_HPP_VAR(xfer_align, snd_pcm_uframes_t)
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ALSA_HPP_VAR(start_threshold, snd_pcm_uframes_t)
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ALSA_HPP_VAR(stop_threshold, snd_pcm_uframes_t)
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ALSA_HPP_VAR(silence_threshold, snd_pcm_uframes_t)
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ALSA_HPP_VAR(silence_size, snd_pcm_uframes_t)
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// Get-only variable
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ALSA_HPP_VARGET(boundary, snd_pcm_uframes_t)
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#undef ALSA_HPP_TEMPLATE
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#undef ALSA_HPP_CLASS
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};
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#undef ALSA_HPP_FUNC
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#undef ALSA_HPP_VAR
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#undef ALSA_HPP_VARGET
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#undef ALSA_HPP_ENUMVAR
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#undef ALSA_HPP_ENUMVARMINIMAL
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#undef ALSA_HPP_BOOLVAR
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#undef ALSA_HPP_RANGEVAR
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#undef ALSA_HPP_RANGEVARDIR
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/** @short A RAII wrapper for snd_pcm_mmap_begin/end block. **/
452
class mmap {
453
snd_pcm_t* pcm;
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public:
455
snd_pcm_channel_area_t const* areas;
456
snd_pcm_uframes_t const offset; // Const for external API
457
snd_pcm_uframes_t frames;
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/**
459
* Initiate MMAP transfer. Returns a buffer via .areas member variable.
460
* snd_pcm_avail_update must be called directly before constructing the
461
* alsa::mmap object, otherwise snd_pcm_mmap_begin may return a wrong
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* count of available frames.
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* @param pcm PCM handle
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* @param fr number of frames to request (check .frames for actual count)
465
**/
466
mmap(snd_pcm_t* pcm, snd_pcm_uframes_t fr): pcm(pcm), areas(), offset(), frames(fr) {
467
ALSA_CHECKED(snd_pcm_mmap_begin, (pcm, &areas, const_cast<snd_pcm_uframes_t*>(&offset), &frames));
468
}
469
/**
470
* End MMAP transfer. If not all frames were used, the count of frames
471
* used be set in .frames member variable before alsa::mmap destruction.
472
**/
473
~mmap() {
474
// We just assume that this works (can't do anything sensible if it fails).
475
snd_pcm_mmap_commit(pcm, offset, frames);
476
}
477
};
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479
}
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#endif
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