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Diffstat (limited to 'plugins/eg-amp.lv2/amp.c')
| -rw-r--r-- | plugins/eg-amp.lv2/amp.c | 230 |
1 files changed, 230 insertions, 0 deletions
diff --git a/plugins/eg-amp.lv2/amp.c b/plugins/eg-amp.lv2/amp.c new file mode 100644 index 0000000..c3ba279 --- /dev/null +++ b/plugins/eg-amp.lv2/amp.c @@ -0,0 +1,230 @@ +/* + Copyright 2006-2016 David Robillard <d@drobilla.net> + Copyright 2006 Steve Harris <steve@plugin.org.uk> + + Permission to use, copy, modify, and/or distribute this software for any + purpose with or without fee is hereby granted, provided that the above + copyright notice and this permission notice appear in all copies. + + THIS SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES + WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF + MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR + ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES + WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN + ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF + OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. +*/ + +/** + LV2 headers are based on the URI of the specification they come from, so a + consistent convention can be used even for unofficial extensions. The URI + of the core LV2 specification is <http://lv2plug.in/ns/lv2core>, by + replacing `http:/` with `lv2` any header in the specification bundle can be + included, in this case `lv2.h`. +*/ +#include "lv2/core/lv2.h" + +/** Include standard C headers */ +#include <math.h> +#include <stdint.h> +#include <stdlib.h> + +/** + The URI is the identifier for a plugin, and how the host associates this + implementation in code with its description in data. In this plugin it is + only used once in the code, but defining the plugin URI at the top of the + file is a good convention to follow. If this URI does not match that used + in the data files, the host will fail to load the plugin. +*/ +#define AMP_URI "http://lv2plug.in/plugins/eg-amp" + +/** + In code, ports are referred to by index. An enumeration of port indices + should be defined for readability. +*/ +typedef enum { + AMP_GAIN = 0, + AMP_INPUT = 1, + AMP_OUTPUT = 2 +} PortIndex; + +/** + Every plugin defines a private structure for the plugin instance. All data + associated with a plugin instance is stored here, and is available to + every instance method. In this simple plugin, only port buffers need to be + stored, since there is no additional instance data. +*/ +typedef struct { + // Port buffers + const float* gain; + const float* input; + float* output; +} Amp; + +/** + The `instantiate()` function is called by the host to create a new plugin + instance. The host passes the plugin descriptor, sample rate, and bundle + path for plugins that need to load additional resources (e.g. waveforms). + The features parameter contains host-provided features defined in LV2 + extensions, but this simple plugin does not use any. + + This function is in the ``instantiation'' threading class, so no other + methods on this instance will be called concurrently with it. +*/ +static LV2_Handle +instantiate(const LV2_Descriptor* descriptor, + double rate, + const char* bundle_path, + const LV2_Feature* const* features) +{ + Amp* amp = (Amp*)calloc(1, sizeof(Amp)); + + return (LV2_Handle)amp; +} + +/** + The `connect_port()` method is called by the host to connect a particular + port to a buffer. The plugin must store the data location, but data may not + be accessed except in run(). + + This method is in the ``audio'' threading class, and is called in the same + context as run(). +*/ +static void +connect_port(LV2_Handle instance, + uint32_t port, + void* data) +{ + Amp* amp = (Amp*)instance; + + switch ((PortIndex)port) { + case AMP_GAIN: + amp->gain = (const float*)data; + break; + case AMP_INPUT: + amp->input = (const float*)data; + break; + case AMP_OUTPUT: + amp->output = (float*)data; + break; + } +} + +/** + The `activate()` method is called by the host to initialise and prepare the + plugin instance for running. The plugin must reset all internal state + except for buffer locations set by `connect_port()`. Since this plugin has + no other internal state, this method does nothing. + + This method is in the ``instantiation'' threading class, so no other + methods on this instance will be called concurrently with it. +*/ +static void +activate(LV2_Handle instance) +{ +} + +/** Define a macro for converting a gain in dB to a coefficient. */ +#define DB_CO(g) ((g) > -90.0f ? powf(10.0f, (g) * 0.05f) : 0.0f) + +/** + The `run()` method is the main process function of the plugin. It processes + a block of audio in the audio context. Since this plugin is + `lv2:hardRTCapable`, `run()` must be real-time safe, so blocking (e.g. with + a mutex) or memory allocation are not allowed. +*/ +static void +run(LV2_Handle instance, uint32_t n_samples) +{ + const Amp* amp = (const Amp*)instance; + + const float gain = *(amp->gain); + const float* const input = amp->input; + float* const output = amp->output; + + const float coef = DB_CO(gain); + + for (uint32_t pos = 0; pos < n_samples; pos++) { + output[pos] = input[pos] * coef; + } +} + +/** + The `deactivate()` method is the counterpart to `activate()`, and is called by + the host after running the plugin. It indicates that the host will not call + `run()` again until another call to `activate()` and is mainly useful for more + advanced plugins with ``live'' characteristics such as those with auxiliary + processing threads. As with `activate()`, this plugin has no use for this + information so this method does nothing. + + This method is in the ``instantiation'' threading class, so no other + methods on this instance will be called concurrently with it. +*/ +static void +deactivate(LV2_Handle instance) +{ +} + +/** + Destroy a plugin instance (counterpart to `instantiate()`). + + This method is in the ``instantiation'' threading class, so no other + methods on this instance will be called concurrently with it. +*/ +static void +cleanup(LV2_Handle instance) +{ + free(instance); +} + +/** + The `extension_data()` function returns any extension data supported by the + plugin. Note that this is not an instance method, but a function on the + plugin descriptor. It is usually used by plugins to implement additional + interfaces. This plugin does not have any extension data, so this function + returns NULL. + + This method is in the ``discovery'' threading class, so no other functions + or methods in this plugin library will be called concurrently with it. +*/ +static const void* +extension_data(const char* uri) +{ + return NULL; +} + +/** + Every plugin must define an `LV2_Descriptor`. It is best to define + descriptors statically to avoid leaking memory and non-portable shared + library constructors and destructors to clean up properly. +*/ +static const LV2_Descriptor descriptor = { + AMP_URI, + instantiate, + connect_port, + activate, + run, + deactivate, + cleanup, + extension_data +}; + +/** + The `lv2_descriptor()` function is the entry point to the plugin library. The + host will load the library and call this function repeatedly with increasing + indices to find all the plugins defined in the library. The index is not an + indentifier, the URI of the returned descriptor is used to determine the + identify of the plugin. + + This method is in the ``discovery'' threading class, so no other functions + or methods in this plugin library will be called concurrently with it. +*/ +LV2_SYMBOL_EXPORT +const LV2_Descriptor* +lv2_descriptor(uint32_t index) +{ + switch (index) { + case 0: return &descriptor; + default: return NULL; + } +} |