Alsa Sequencer tests.

2025-06-27 04:49:52 -04:00
parent 07af383211
commit 96af9287ba
5 changed files with 547 additions and 9 deletions
@@ -0,0 +1,126 @@
+/*
+ *   Copyright (c) 2025 Robin E. R. Davies
+ *   All rights reserved.
+
+ *   Permission is hereby granted, free of charge, to any person obtaining a copy
+ *   of this software and associated documentation files (the "Software"), to deal
+ *   in the Software without restriction, including without limitation the rights
+ *   to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ *   copies of the Software, and to permit persons to whom the Software is
+ *   furnished to do so, subject to the following conditions:
+
+ *   The above copyright notice and this permission notice shall be included in all
+ *   copies or substantial portions of the Software.
+
+ *   THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ *   IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ *   FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ *   AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ *   LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ *   OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ *   SOFTWARE.
+ */
+
+#pragma once
+
+#include <vector>
+#include <string>
+#include <alsa/asoundlib.h>
+#include <alsa/seq.h>
+#include <stdexcept>
+
+namespace pipedal
+{
+    struct AlsaSequencerPort
+    {
+        std::string id;
+        int client;
+        int port;
+        std::string name;
+        std::string clientName;
+        bool canRead = false;
+        bool canWrite = false;
+        bool canReadSubscribe = false;
+        bool canWriteSubscribe = false;
+
+        bool isKernelDevice = false;
+        bool isSystemAnnounce = false;
+        bool isUmp = false;
+        bool isMidi = false;
+        bool isApplication = false;
+        bool isMidiSynth = false;
+        bool isSynth = false;
+        bool isSpecific;
+        bool isHardware = false;
+        bool isSoftware = false;
+        int cardNumber = -1;
+        std::string rawMidiDevice; // e.g. "hw:0,0,0" for kernel devices
+    };
+
+    struct AlsaMidiMessage
+    {
+        uint32_t timestamp; // in microseconds (tick time if using queue)
+        uint64_t realtime_sec;  // real-time timestamp seconds
+        uint32_t realtime_nsec; // real-time timestamp nanoseconds
+        uint8_t cc0;
+        uint8_t cc1;
+        uint8_t cc2;
+    };
+
+    /*
+     * AlsaSequencer - ALSA MIDI sequencer interface with real-time timestamp support
+     * 
+     * Example usage with real-time timestamps:
+     * 
+     *   AlsaSequencer sequencer;
+     *   sequencer.connect(clientId, portId);
+     *   
+     *   AlsaMidiMessage message;
+     *   while (sequencer.ReadMessage(&message)) {
+     *       // message.realtime_sec and message.realtime_nsec contain precise real-time timestamps
+     *       // message.timestamp contains the queue tick time
+     *       printf("MIDI event at %lu.%09u seconds\n", message.realtime_sec, message.realtime_nsec);
+     *   }
+     */
+    class AlsaSequencer
+    {
+    public:
+        static std::vector<AlsaSequencerPort> EnumeratePorts();
+
+        AlsaSequencer();
+        ~AlsaSequencer();
+
+        void ConnectPort(int clientId, int portId);
+        void ConnectPort(const std::string&name);
+
+        // Read a single MIDI message from the sequencer input port
+        bool ReadMessage(AlsaMidiMessage &message);
+
+
+        // Get current real-time from the queue (useful for calculating precise timing)
+        bool GetQueueRealtime(uint64_t* sec, uint32_t* nsec);
+
+        // Get the current queue ID (returns -1 if no queue is active)
+        int GetQueueId() const { return queueId; }
+
+    private:
+        // Create an ALSA input queue with real-time timestamps for the given client/port
+        int CreateRealtimeInputQueue();
+
+        struct Connection
+        {
+            int clientId;
+            int portId;
+        };
+
+        std::vector<Connection> connections;
+
+        snd_seq_t *seqHandle = nullptr;
+        int inPort = -1;
+        int queueId = -1;  // Queue for real-time timestamps
+
+        // Example: open an ALSA sequencer input port and read MIDI events continuously
+        void ReadMidiFromPort(int clientId, int portId);
+    };
+
+}