Add basic WAV file reader for use in examples.

Signed-off-by: iabdalkader <[email protected]>

Author: iabdalkader

src/Arduino_AdvancedAnalog.h

@@ -26,5 +26,6 @@
 
 #include "AdvancedADC.h"
 #include "AdvancedDAC.h"
+#include "WavReader.h"
 
 #endif /* ADVANCEDANALOGREDUX_ARDUINO_ADVANCEDANALOG_H */

src/WavReader.cpp

@@ -0,0 +1,108 @@
+/*
+  This file is part of the Arduino_AdvancedAnalog library.
+  Copyright (c) 2024 Arduino SA. All rights reserved.
+
+  This library is free software; you can redistribute it and/or
+  modify it under the terms of the GNU Lesser General Public
+  License as published by the Free Software Foundation; either
+  version 2.1 of the License, or (at your option) any later version.
+
+  This library 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
+  Lesser General Public License for more details.
+
+  You should have received a copy of the GNU Lesser General Public
+  License along with this library; if not, write to the Free Software
+  Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
+*/
+
+#include "Arduino.h"
+#include "WavReader.h"
+
+WavReader::~WavReader() {
+    stop();
+}
+
+int WavReader::begin(const char *path, size_t n_samples, size_t n_buffers, bool loop) {
+    this->loop = loop;
+
+    if ((file = fopen(path, "rb")) == nullptr) {
+        return 0;
+    }
+
+    // Read file header
+    fread(&header, sizeof(header), 1, file);
+
+    // Add more sanity checks if needed.
+    if (memcmp(header.chunk_id, "RIFF", 4) != 0 ||
+        memcmp(header.format, "WAVEfmt", 7) != 0 ||
+        (n_samples * header.num_channels) > sample_count()) {
+        stop();
+        return 0;
+    }
+
+    // Allocate the DMA buffer pool.
+    pool = new DMABufferPool<Sample>(n_samples, header.num_channels, n_buffers);
+    if (pool == nullptr) {
+        stop();
+        return 0;
+    }
+    return 1;
+}
+
+void WavReader::stop() {
+    if (file) {
+        fclose(file);
+    }
+    if (pool) {
+        delete pool;
+    }
+    pool = nullptr;
+    file = nullptr;
+}
+
+bool WavReader::available() {
+    if (file != nullptr && pool != nullptr) {
+        return pool->writable();
+    }
+    return false;
+}
+
+DMABuffer<Sample> &WavReader::read() {
+    while (!available()) {
+        __WFI();
+    }
+
+    DMABuffer<Sample> *buf = pool->allocate();
+    size_t offset = 0;
+    Sample *rawbuf = buf->data();
+    size_t n_samples = buf->size();
+
+    while (offset < n_samples) {
+        offset += fread(&rawbuf[offset], sizeof(Sample), n_samples - offset, file);
+        if (offset < n_samples) {
+            if (loop) {
+                rewind();
+            } else {
+                for (size_t i=offset; i<n_samples; i++) {
+                    rawbuf[i] = 0;
+                }
+                fclose(file);
+                file = nullptr;
+                break;
+            }
+        }
+    }
+    return *buf;
+}
+
+int WavReader::rewind() {
+    if (file == nullptr) {
+        return 0;
+    }
+    if (fseek(file, sizeof(WavHeader), SEEK_SET) == -1) {
+        return 0;
+    }
+    return 1;
+}

src/WavReader.h

@@ -0,0 +1,74 @@
+/*
+  This file is part of the Arduino_AdvancedAnalog library.
+  Copyright (c) 2024 Arduino SA. All rights reserved.
+
+  This library is free software; you can redistribute it and/or
+  modify it under the terms of the GNU Lesser General Public
+  License as published by the Free Software Foundation; either
+  version 2.1 of the License, or (at your option) any later version.
+
+  This library 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
+  Lesser General Public License for more details.
+
+  You should have received a copy of the GNU Lesser General Public
+  License along with this library; if not, write to the Free Software
+  Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
+*/
+
+#include "AdvancedAnalog.h"
+
+#ifndef ARDUINO_WAV_READER_H_
+#define ARDUINO_WAV_READER_H_
+
+class WavReader {
+    typedef struct {
+        char chunk_id[4];
+        unsigned int chunk_size;
+        char format[4];
+        char subchunk1_id[4];
+        unsigned int subchunk1_size;
+        unsigned short audio_format;
+        unsigned short num_channels;
+        unsigned int sample_rate;
+        unsigned int byte_rate;
+        unsigned short block_align;
+        unsigned short bits_per_sample;
+        char subchunk2_id[4];
+        unsigned int subchunk2_size;
+    } WavHeader;
+
+    private:
+        FILE *file;
+        bool loop;
+        WavHeader header;
+        DMABufferPool<Sample> *pool;
+
+    public:
+        WavReader(): file(nullptr), loop(false), pool(nullptr) {
+        }
+        ~WavReader();
+        size_t channels() {
+            return header.num_channels;
+        }
+
+        size_t resolution() {
+            return header.bits_per_sample;
+        }
+
+        size_t sample_rate() {
+            return header.sample_rate;
+        }
+
+        size_t sample_count() {
+            return (header.subchunk2_size * 8) / header.bits_per_sample;
+        }
+
+        int begin(const char *path, size_t n_samples, size_t n_buffers, bool loop=false);
+        void stop();
+        bool available();
+        SampleBuffer read();
+        int rewind();
+};
+#endif /* ARDUINO_WAV_READER_H_ */