From bfb3fd8776cb89b5ccb042cf28e791f42927dc8f Mon Sep 17 00:00:00 2001
From: David Adams <none>
Date: Fri, 9 May 2025 22:50:00 -0700
Subject: [PATCH 1/3] Samples from an AudioFile<double> are cast to float and a
 reference is taken *before* reinterpret_cat to int32_t& followed by cast to
 int32_t when an AudioFile<double> is saved to IEEE 32-bit float WAV.

---
 AudioFile.h | 11 ++++++++++-
 1 file changed, 10 insertions(+), 1 deletion(-)

diff --git a/AudioFile.h b/AudioFile.h
index bc71da8..2b2ec4a 100644
--- a/AudioFile.h
+++ b/AudioFile.h
@@ -995,7 +995,16 @@ bool AudioFile<T>::encodeWaveFile (std::vector<uint8_t>& fileData)
                 int32_t sampleAsInt;
                 
                 if (audioFormat == WavAudioFormat::IEEEFloat)
-                    sampleAsInt = (int32_t) reinterpret_cast<int32_t&> (samples[channel][i]);
+                {
+                    if constexpr (std::is_same_v<T, float>)
+                        sampleAsInt = (int32_t) reinterpret_cast<int32_t&> (samples[channel][i]);
+                    else if constexpr (std::is_same_v<T, double>)
+                    {
+                        auto sampleAsFloat = (float) samples[channel][i];
+                        float& referenceToSample = sampleAsFloat;
+                        sampleAsInt = (int32_t) reinterpret_cast<int32_t&> (referenceToSample);
+                    }
+                }
                 else // assume PCM
                     sampleAsInt = AudioSampleConverter<T>::sampleToThirtyTwoBitInt (samples[channel][i]);
                 

From 7c07038c9b58a46ee56de42ae92347bf79b740b9 Mon Sep 17 00:00:00 2001
From: Adam Stark <adamstark.uk@gmail.com>
Date: Fri, 30 May 2025 22:48:54 +0100
Subject: [PATCH 2/3] Ensure we are re-reading and testing 32-bit files and
 test double precision

---
 tests/FileWritingTests.cpp | 34 +++++++++++++++++++++++++++++-----
 1 file changed, 29 insertions(+), 5 deletions(-)

diff --git a/tests/FileWritingTests.cpp b/tests/FileWritingTests.cpp
index 434d397..33f92a1 100644
--- a/tests/FileWritingTests.cpp
+++ b/tests/FileWritingTests.cpp
@@ -85,10 +85,9 @@ void writeTestAudioFile (int numChannels, int sampleRate, int bitDepth, AudioFil
     REQUIRE (OK);
     
     //-----------------------------------------------------------------
-    // for some key bit depths and mono/stereo files, read in the audio file
-    // we just wrote and do a sample-by-sample comparison to confirm we are
-    // writing good files
-    if ((bitDepth == 8 || bitDepth == 16 || bitDepth == 24) &&  numChannels <= 2)
+    // read in the audio file we just wrote and do a sample-by-sample
+    // comparison to confirm we are writing good files
+    if (numChannels <= 2)
     {
         AudioFile<T> audioFileReader;
         audioFileReader.load (filePath);
@@ -136,13 +135,38 @@ TEST_SUITE ("Writing Tests")
                     for (auto& format : audioFormats)
                     {
                         auto fmt_str = format == AudioFileFormat::Wave ? "wav" : "aiff";
-                        std::cerr << sampleRate << "Hz " << bitDepth << "-bit " << channels << " " << fmt_str << " (floating point)" << std::endl;
+                        std::cerr << sampleRate << "Hz " << bitDepth << "-bit " << channels << " " << fmt_str << " (float)" << std::endl;
                         writeTestAudioFile<float> (channels, sampleRate, bitDepth, format);
                     }
                 }
             }
         }
     }
+    
+    //=============================================================
+    TEST_CASE ("WritingTest::WriteSineToneToManyFormats::DoublePrecision")
+    {
+        std::vector<int> sampleRates = {22050, 44100, 48000, 96000};
+        std::vector<int> bitDepths = {8, 16, 24, 32};
+        std::vector<int> numChannels = {1, 2, 8};
+        std::vector<AudioFileFormat> audioFormats = {AudioFileFormat::Wave, AudioFileFormat::Aiff};
+        
+        for (auto& sampleRate : sampleRates)
+        {
+            for (auto& bitDepth : bitDepths)
+            {
+                for (auto& channels : numChannels)
+                {
+                    for (auto& format : audioFormats)
+                    {
+                        auto fmt_str = format == AudioFileFormat::Wave ? "wav" : "aiff";
+                        std::cerr << sampleRate << "Hz " << bitDepth << "-bit " << channels << " " << fmt_str << " (double)" << std::endl;
+                        writeTestAudioFile<double> (channels, sampleRate, bitDepth, format);
+                    }
+                }
+            }
+        }
+    }
 
     //=============================================================
     TEST_CASE ("WritingTest::WriteSineToneToManyFormats::Integer")

From ee362897684e55935b0ee694a70dd48a46c28dce Mon Sep 17 00:00:00 2001
From: Adam Stark <adamstark.uk@gmail.com>
Date: Fri, 30 May 2025 22:49:09 +0100
Subject: [PATCH 3/3] style: add brackets for consistency

---
 AudioFile.h | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/AudioFile.h b/AudioFile.h
index 2b2ec4a..3897949 100644
--- a/AudioFile.h
+++ b/AudioFile.h
@@ -997,7 +997,9 @@ bool AudioFile<T>::encodeWaveFile (std::vector<uint8_t>& fileData)
                 if (audioFormat == WavAudioFormat::IEEEFloat)
                 {
                     if constexpr (std::is_same_v<T, float>)
+                    {
                         sampleAsInt = (int32_t) reinterpret_cast<int32_t&> (samples[channel][i]);
+                    }
                     else if constexpr (std::is_same_v<T, double>)
                     {
                         auto sampleAsFloat = (float) samples[channel][i];
@@ -1006,7 +1008,9 @@ bool AudioFile<T>::encodeWaveFile (std::vector<uint8_t>& fileData)
                     }
                 }
                 else // assume PCM
+                {
                     sampleAsInt = AudioSampleConverter<T>::sampleToThirtyTwoBitInt (samples[channel][i]);
+                }
                 
                 addInt32ToFileData (fileData, sampleAsInt, Endianness::LittleEndian);
             }