Initial commit

tests/clap/ext/thread-pool.h

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+#pragma once
+
+#include "../plugin.h"
+
+/// @page
+///
+/// This extension lets the plugin use the host's thread pool.
+///
+/// The plugin must provide @ref clap_plugin_thread_pool, and the host may provide @ref
+/// clap_host_thread_pool. If it doesn't, the plugin should process its data by its own means. In
+/// the worst case, a single threaded for-loop.
+///
+/// Simple example with N voices to process
+///
+/// @code
+/// void myplug_thread_pool_exec(const clap_plugin *plugin, uint32_t voice_index)
+/// {
+///    compute_voice(plugin, voice_index);
+/// }
+///
+/// void myplug_process(const clap_plugin *plugin, const clap_process *process)
+/// {
+///    ...
+///    bool didComputeVoices = false;
+///    if (host_thread_pool && host_thread_pool.exec)
+///       didComputeVoices = host_thread_pool.request_exec(host, plugin, N);
+///
+///    if (!didComputeVoices)
+///       for (uint32_t i = 0; i < N; ++i)
+///          myplug_thread_pool_exec(plugin, i);
+///    ...
+/// }
+/// @endcode
+///
+/// Be aware that using a thread pool may break hard real-time rules due to the thread
+/// synchronization involved.
+///
+/// If the host knows that it is running under hard real-time pressure it may decide to not
+/// provide this interface.
+
+static CLAP_CONSTEXPR const char CLAP_EXT_THREAD_POOL[] = "clap.thread-pool";
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+typedef struct clap_plugin_thread_pool {
+   // Called by the thread pool
+   void(CLAP_ABI *exec)(const clap_plugin_t *plugin, uint32_t task_index);
+} clap_plugin_thread_pool_t;
+
+typedef struct clap_host_thread_pool {
+   // Schedule num_tasks jobs in the host thread pool.
+   // It can't be called concurrently or from the thread pool.
+   // Will block until all the tasks are processed.
+   // This must be used exclusively for realtime processing within the process call.
+   // Returns true if the host did execute all the tasks, false if it rejected the request.
+   // The host should check that the plugin is within the process call, and if not, reject the exec
+   // request.
+   // [audio-thread]
+   bool(CLAP_ABI *request_exec)(const clap_host_t *host, uint32_t num_tasks);
+} clap_host_thread_pool_t;
+
+#ifdef __cplusplus
+}
+#endif