LibAudio: Move Audio::Buffer implementation into its own file

Author: https://github.com/janso3
Commit: https://github.com/SerenityOS/serenity/commit/dff59837068
Pull-request: https://github.com/SerenityOS/serenity/pull/4295
Reviewed-by: https://github.com/awesomekling

Libraries/LibAudio/Buffer.cpp

@@ -0,0 +1,134 @@
+/*
+ * Copyright (c) 2018-2020, Andreas Kling <kling@serenityos.org>
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice, this
+ *    list of conditions and the following disclaimer.
+ *
+ * 2. Redistributions in binary form must reproduce the above copyright notice,
+ *    this list of conditions and the following disclaimer in the documentation
+ *    and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+ * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+ * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
+ * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+ * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include <LibAudio/Buffer.h>
+
+namespace Audio {
+
+template<typename SampleReader>
+static void read_samples_from_stream(InputMemoryStream& stream, SampleReader read_sample, Vector<Sample>& samples, ResampleHelper& resampler, int num_channels)
+{
+    double norm_l = 0;
+    double norm_r = 0;
+
+    switch (num_channels) {
+    case 1:
+        for (;;) {
+            while (resampler.read_sample(norm_l, norm_r)) {
+                samples.append(Sample(norm_l));
+            }
+            norm_l = read_sample(stream);
+
+            if (stream.handle_any_error()) {
+                break;
+            }
+            resampler.process_sample(norm_l, norm_r);
+        }
+        break;
+    case 2:
+        for (;;) {
+            while (resampler.read_sample(norm_l, norm_r)) {
+                samples.append(Sample(norm_l, norm_r));
+            }
+            norm_l = read_sample(stream);
+            norm_r = read_sample(stream);
+
+            if (stream.handle_any_error()) {
+                break;
+            }
+            resampler.process_sample(norm_l, norm_r);
+        }
+        break;
+    default:
+        ASSERT_NOT_REACHED();
+    }
+}
+
+static double read_norm_sample_24(InputMemoryStream& stream)
+{
+    u8 byte = 0;
+    stream >> byte;
+    u32 sample1 = byte;
+    stream >> byte;
+    u32 sample2 = byte;
+    stream >> byte;
+    u32 sample3 = byte;
+
+    i32 value = 0;
+    value = sample1 << 8;
+    value |= (sample2 << 16);
+    value |= (sample3 << 24);
+    return double(value) / NumericLimits<i32>::max();
+}
+
+static double read_norm_sample_16(InputMemoryStream& stream)
+{
+    LittleEndian<i16> sample;
+    stream >> sample;
+    return double(sample) / NumericLimits<i16>::max();
+}
+
+static double read_norm_sample_8(InputMemoryStream& stream)
+{
+    u8 sample = 0;
+    stream >> sample;
+    return double(sample) / NumericLimits<u8>::max();
+}
+    
+RefPtr<Buffer> Buffer::from_pcm_data(ReadonlyBytes data, ResampleHelper& resampler, int num_channels, int bits_per_sample)
+{
+    InputMemoryStream stream { data };
+    return from_pcm_stream(stream, resampler, num_channels, bits_per_sample, data.size() / (bits_per_sample / 8));
+}
+
+RefPtr<Buffer> Buffer::from_pcm_stream(InputMemoryStream &stream, ResampleHelper& resampler, int num_channels, int bits_per_sample, int num_samples)
+{
+    Vector<Sample> fdata;
+    fdata.ensure_capacity(num_samples);
+
+    switch (bits_per_sample) {
+    case 8:
+        read_samples_from_stream(stream, read_norm_sample_8, fdata, resampler, num_channels);
+        break;
+    case 16:
+        read_samples_from_stream(stream, read_norm_sample_16, fdata, resampler, num_channels);
+        break;
+    case 24:
+        read_samples_from_stream(stream, read_norm_sample_24, fdata, resampler, num_channels);
+        break;
+    default:
+        ASSERT_NOT_REACHED();
+    }
+
+    // We should handle this in a better way above, but for now --
+    // just make sure we're good. Worst case we just write some 0s where they
+    // don't belong.
+    ASSERT(!stream.handle_any_error());
+
+    return Buffer::create_with_samples(move(fdata));
+}
+
+}

Libraries/LibAudio/Buffer.h

@@ -27,6 +27,7 @@
 #pragma once
 
 #include <AK/ByteBuffer.h>
+#include <AK/MemoryStream.h>
 #include <AK/SharedBuffer.h>
 #include <AK/Types.h>
 #include <AK/Vector.h>
@@ -108,7 +109,8 @@ private:
 // A buffer of audio samples, normalized to 44100hz.
 class Buffer : public RefCounted<Buffer> {
 public:
-    static RefPtr<Buffer> from_pcm_data(ReadonlyBytes, ResampleHelper& resampler, int num_channels, int bits_per_sample);
+    static RefPtr<Buffer> from_pcm_data(ReadonlyBytes data, ResampleHelper& resampler, int num_channels, int bits_per_sample);
+    static RefPtr<Buffer> from_pcm_stream(InputMemoryStream& stream, ResampleHelper& resampler, int num_channels, int bits_per_sample, int num_samples);
     static NonnullRefPtr<Buffer> create_with_samples(Vector<Sample>&& samples)
     {
         return adopt(*new Buffer(move(samples)));

Libraries/LibAudio/CMakeLists.txt

@@ -1,4 +1,5 @@
 set(SOURCES
+    Buffer.cpp
     ClientConnection.cpp
     Loader.cpp
     WavLoader.cpp