Driver for file-based audio input device

meson.build

@@ -285,6 +285,7 @@ linux_platform_src = ['platform/targets/linux/emulator/emulator.c',
                       'platform/mcu/x86_64/drivers/rng.cpp',
                       'platform/drivers/baseband/radio_linux.cpp',
                       'platform/drivers/audio/audio_linux.c',
+                      'platform/drivers/audio/file_source.c',
                       'platform/targets/linux/platform.c',
                       'platform/drivers/CPS/cps_io_libc.c']
 

platform/drivers/audio/file_source.c

@@ -0,0 +1,120 @@
+/***************************************************************************
+ *   Copyright (C) 2023 by Federico Amedeo Izzo IU2NUO,                    *
+ *                         Niccolò Izzo IU2KIN                             *
+ *                         Frederik Saraci IU2NRO                          *
+ *                         Silvano Seva IU2KWO                             *
+ *                                                                         *
+ *   This program is free software; you can redistribute it and/or modify  *
+ *   it under the terms of the GNU General Public License as published by  *
+ *   the Free Software Foundation; either version 3 of the License, or     *
+ *   (at your option) any later version.                                   *
+ *                                                                         *
+ *   This program is distributed in the hope that it will be useful,       *
+ *   but WITHOUT ANY WARRANTY; without even the implied warranty of        *
+ *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the         *
+ *   GNU General Public License for more details.                          *
+ *                                                                         *
+ *   You should have received a copy of the GNU General Public License     *
+ *   along with this program; if not, see <http://www.gnu.org/licenses/>   *
+ ***************************************************************************/
+
+#include <stdlib.h>
+#include <unistd.h>
+#include <stdio.h>
+#include <errno.h>
+#include "file_source.h"
+
+static int fileSource_start(const uint8_t instance, const void *config, struct streamCtx *ctx)
+{
+    (void) instance;
+
+    if(ctx == NULL)
+        return -EINVAL;
+
+    if(ctx->running != 0)
+        return -EBUSY;
+
+    ctx->running = 1;
+
+    FILE *fp = fopen(config, "rb");
+    if(fp == NULL)
+    {
+        ctx->running = 0;
+        return -EINVAL;
+    }
+
+    ctx->priv = fp;
+
+    return 0;
+}
+
+static int fileSource_data(struct streamCtx *ctx, stream_sample_t **buf)
+{
+    if(ctx->running == 0)
+        return -1;
+
+    FILE *fp  = (FILE *) ctx->priv;
+    stream_sample_t *dest = *buf;
+    size_t size = ctx->bufSize;
+    size_t i;
+
+    if(ctx->bufMode == BUF_CIRC_DOUBLE)
+        size /= 2;
+
+    // Read data from the file, rollover when end is reached
+    while (i < size)
+    {
+        size_t n = fread(dest + i, sizeof(stream_sample_t), size - i, fp);
+        if (n < (size - i))
+            fseek(fp, 0, SEEK_SET);
+
+        i += n;
+    }
+
+    return size;
+}
+
+static int fileSource_sync(struct streamCtx *ctx, uint8_t dirty)
+{
+    (void) dirty;
+
+    size_t size = ctx->bufSize;
+    if(ctx->bufMode == BUF_CIRC_DOUBLE)
+        size /= 2;
+
+    // Simulate the time needed to get a new chunck of data from an equivalent
+    // hardware peripheral.
+    uint32_t waitTime = (1000000 * size) / ctx->sampleRate;
+    usleep(waitTime);
+
+    return 0;
+}
+
+static void fileSource_stop(struct streamCtx *ctx)
+{
+    if(ctx->running == 0)
+        return;
+
+    FILE *fp = (FILE *) ctx->priv;
+    fclose(fp);
+}
+
+static void fileSource_halt(struct streamCtx *ctx)
+{
+    if(ctx->running == 0)
+        return;
+
+    FILE *fp = (FILE *) ctx->priv;
+    fclose(fp);
+}
+
+#pragma GCC diagnostic ignored "-Wpedantic"
+const struct audioDriver file_source_audio_driver =
+{
+    .start     = fileSource_start,
+    .data      = fileSource_data,
+    .sync      = fileSource_sync,
+    .stop      = fileSource_stop,
+    .terminate = fileSource_halt
+};
+#pragma GCC diagnostic pop

platform/drivers/audio/file_source.h

@@ -0,0 +1,43 @@
+/***************************************************************************
+ *   Copyright (C) 2023 by Federico Amedeo Izzo IU2NUO,                    *
+ *                         Niccolò Izzo IU2KIN                             *
+ *                         Frederik Saraci IU2NRO                          *
+ *                         Silvano Seva IU2KWO                             *
+ *                                                                         *
+ *   This program is free software; you can redistribute it and/or modify  *
+ *   it under the terms of the GNU General Public License as published by  *
+ *   the Free Software Foundation; either version 3 of the License, or     *
+ *   (at your option) any later version.                                   *
+ *                                                                         *
+ *   This program is distributed in the hope that it will be useful,       *
+ *   but WITHOUT ANY WARRANTY; without even the implied warranty of        *
+ *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the         *
+ *   GNU General Public License for more details.                          *
+ *                                                                         *
+ *   You should have received a copy of the GNU General Public License     *
+ *   along with this program; if not, see <http://www.gnu.org/licenses/>   *
+ ***************************************************************************/
+
+#ifndef FILE_SOURCE_H
+#define FILE_SOURCE_H
+
+#include <interfaces/audio.h>
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/**
+ * Driver providing an audio input stream from a file. File format should be
+ * raw, 16 bit, little endian. The configuration parameter is the file name with
+ * the full path.
+ */
+
+extern const struct audioDriver file_source_audio_driver;
+
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* STM32_DAC_H */