Fix FileSize for saving .wav

go.mod

@@ -8,19 +8,24 @@ require (
 	github.com/hajimehoshi/oto v0.7.1
 	github.com/jfreymuth/oggvorbis v1.0.1
 	github.com/mewkiz/flac v1.0.7
+	github.com/orcaman/writerseeker v0.0.0-20200621085525-1d3f536ff85e
 	github.com/pkg/errors v0.9.1
+	github.com/stretchr/testify v1.8.4
 )
 
 require (
+	github.com/davecgh/go-spew v1.1.1 // indirect
 	github.com/gdamore/encoding v1.0.0 // indirect
 	github.com/icza/bitio v1.0.0 // indirect
 	github.com/jfreymuth/vorbis v1.0.0 // indirect
 	github.com/lucasb-eyer/go-colorful v1.0.2 // indirect
 	github.com/mattn/go-runewidth v0.0.4 // indirect
 	github.com/mewkiz/pkg v0.0.0-20190919212034-518ade7978e2 // indirect
+	github.com/pmezard/go-difflib v1.0.0 // indirect
 	golang.org/x/exp v0.0.0-20190306152737-a1d7652674e8 // indirect
 	golang.org/x/image v0.0.0-20190227222117-0694c2d4d067 // indirect
 	golang.org/x/mobile v0.0.0-20190415191353-3e0bab5405d6 // indirect
 	golang.org/x/sys v0.0.0-20190626150813-e07cf5db2756 // indirect
 	golang.org/x/text v0.3.0 // indirect
+	gopkg.in/yaml.v3 v3.0.1 // indirect
 )

go.sum

@@ -1,6 +1,8 @@
 github.com/DATA-DOG/go-sqlmock v1.3.3 h1:CWUqKXe0s8A2z6qCgkP4Kru7wC11YoAnoupUKFDnH08=
 github.com/DATA-DOG/go-sqlmock v1.3.3/go.mod h1:f/Ixk793poVmq4qj/V1dPUg2JEAKC73Q5eFN3EC/SaM=
 github.com/d4l3k/messagediff v1.2.2-0.20190829033028-7e0a312ae40b/go.mod h1:Oozbb1TVXFac9FtSIxHBMnBCq2qeH/2KkEQxENCrlLo=
+github.com/davecgh/go-spew v1.1.1 h1:vj9j/u1bqnvCEfJOwUhtlOARqs3+rkHYY13jYWTU97c=
+github.com/davecgh/go-spew v1.1.1/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
 github.com/gdamore/encoding v1.0.0 h1:+7OoQ1Bc6eTm5niUzBa0Ctsh6JbMW6Ra+YNuAtDBdko=
 github.com/gdamore/encoding v1.0.0/go.mod h1:alR0ol34c49FCSBLjhosxzcPHQbf2trDkoo5dl+VrEg=
 github.com/gdamore/tcell v1.3.0 h1:r35w0JBADPZCVQijYebl6YMWWtHRqVEGt7kL2eBADRM=
@@ -29,9 +31,15 @@ github.com/mewkiz/flac v1.0.7 h1:uIXEjnuXqdRaZttmSFM5v5Ukp4U6orrZsnYGGR3yow8=
 github.com/mewkiz/flac v1.0.7/go.mod h1:yU74UH277dBUpqxPouHSQIar3G1X/QIclVbFahSd1pU=
 github.com/mewkiz/pkg v0.0.0-20190919212034-518ade7978e2 h1:EyTNMdePWaoWsRSGQnXiSoQu0r6RS1eA557AwJhlzHU=
 github.com/mewkiz/pkg v0.0.0-20190919212034-518ade7978e2/go.mod h1:3E2FUC/qYUfM8+r9zAwpeHJzqRVVMIYnpzD/clwWxyA=
+github.com/orcaman/writerseeker v0.0.0-20200621085525-1d3f536ff85e h1:s2RNOM/IGdY0Y6qfTeUKhDawdHDpK9RGBdx80qN4Ttw=
+github.com/orcaman/writerseeker v0.0.0-20200621085525-1d3f536ff85e/go.mod h1:nBdnFKj15wFbf94Rwfq4m30eAcyY9V/IyKAGQFtqkW0=
 github.com/pkg/errors v0.8.1/go.mod h1:bwawxfHBFNV+L2hUp1rHADufV3IMtnDRdf1r5NINEl0=
 github.com/pkg/errors v0.9.1 h1:FEBLx1zS214owpjy7qsBeixbURkuhQAwrK5UwLGTwt4=
 github.com/pkg/errors v0.9.1/go.mod h1:bwawxfHBFNV+L2hUp1rHADufV3IMtnDRdf1r5NINEl0=
+github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZbAQM=
+github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
+github.com/stretchr/testify v1.8.4 h1:CcVxjf3Q8PM0mHUKJCdn+eZZtm5yQwehR5yeSVQQcUk=
+github.com/stretchr/testify v1.8.4/go.mod h1:sz/lmYIOXD/1dqDmKjjqLyZ2RngseejIcXlSw2iwfAo=
 golang.org/x/exp v0.0.0-20190306152737-a1d7652674e8 h1:idBdZTd9UioThJp8KpM/rTSinK/ChZFBE43/WtIy8zg=
 golang.org/x/exp v0.0.0-20190306152737-a1d7652674e8/go.mod h1:CJ0aWSM057203Lf6IL+f9T1iT9GByDxfZKAQTCR3kQA=
 golang.org/x/image v0.0.0-20190220214146-31aff87c08e9/go.mod h1:kZ7UVZpmo3dzQBMxlp+ypCbDeSB+sBbTgSJuh5dn5js=
@@ -46,3 +54,7 @@ golang.org/x/sys v0.0.0-20190626150813-e07cf5db2756 h1:9nuHUbU8dRnRRfj9KjWUVrJeo
 golang.org/x/sys v0.0.0-20190626150813-e07cf5db2756/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
 golang.org/x/text v0.3.0 h1:g61tztE5qeGQ89tm6NTjjM9VPIm088od1l6aSorWRWg=
 golang.org/x/text v0.3.0/go.mod h1:NqM8EUOU14njkJ3fqMW+pc6Ldnwhi/IjpwHt7yyuwOQ=
+gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405 h1:yhCVgyC4o1eVCa2tZl7eS0r+SDo693bJlVdllGtEeKM=
+gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
+gopkg.in/yaml.v3 v3.0.1 h1:fxVm/GzAzEWqLHuvctI91KS9hhNmmWOoWu0XTYJS7CA=
+gopkg.in/yaml.v3 v3.0.1/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=

wav/decode_test.go

@@ -0,0 +1,105 @@
+package wav
+
+import (
+	"bytes"
+	"github.com/gopxl/beep"
+	"github.com/stretchr/testify/assert"
+	"testing"
+)
+
+func TestDecode(t *testing.T) {
+	wav := []byte{
+		// Riff mark
+		'R', 'I', 'F', 'F',
+		// File size without riff mark and file size
+		0x38, 0x00, 0x00, 0x00, // 56 bytes
+		// Wave mark
+		'W', 'A', 'V', 'E',
+
+		// Fmt mark
+		'f', 'm', 't', ' ',
+		// Format chunk size
+		0x10, 0x00, 0x00, 0x00, // 16 bytes
+		// Format type
+		0x01, 0x00, // 1 = PCM
+		// Number of channels,
+		0x02, 0x00,
+		// Sample rate
+		0x44, 0xAC, 0x00, 0x00, // 44100 samples/sec
+		// Byte rate
+		0x10, 0xB1, 0x02, 0x00, // 44100 * 2 bytes/sample precision * 2 channels = 176400 bytes/sec
+		// Bytes per frame
+		0x04, 0x00, // 2 bytes/sample precision * 2 channels = 4 bytes/frame
+		// Bits per sample
+		0x10, 0x00, // 2 bytes/sample precision = 16 bits/sample
+
+		// Data mark
+		'd', 'a', 't', 'a',
+		// Data size
+		0x14, 0x00, 0x00, 0x00, // 5 samples * 2 bytes/sample precision * 2 channels = 20 bytes
+		// Data
+		0x00, 0x00, 0x00, 0x00,
+		0x00, 0x00, 0x00, 0x00,
+		0x00, 0x00, 0x00, 0x00,
+		0x00, 0x00, 0x00, 0x00,
+		0x00, 0x00, 0x00, 0x00,
+	}
+
+	r := bytes.NewReader(wav)
+
+	s, f, err := Decode(r)
+	if err != nil {
+		t.Fatalf("failed to decode the WAV file: %v", err)
+	}
+
+	assert.Equal(t, beep.Format{
+		SampleRate:  44100,
+		NumChannels: 2,
+		Precision:   2,
+	}, f)
+
+	assert.NoError(t, s.Err())
+	assert.Equal(t, 5, s.Len())
+	assert.Equal(t, 0, s.Position())
+
+	samples := make([][2]float64, 3)
+	// Stream first few bytes
+	n, ok := s.Stream(samples)
+	assert.Equal(t, 3, n)
+	assert.Truef(t, ok, "the decoder failed to stream the samples")
+	assert.Equal(t, 3, s.Position())
+	assert.NoError(t, s.Err())
+	// Drain the streamer
+	n, ok = s.Stream(samples)
+	assert.Equal(t, 2, n)
+	assert.Truef(t, ok, "the decoder failed to stream the samples")
+	assert.Equal(t, 5, s.Position())
+	assert.NoError(t, s.Err())
+	// Drain the streamer some more
+	n, ok = s.Stream(samples)
+	assert.Equal(t, 0, n)
+	assert.Equal(t, 5, s.Position())
+	assert.Falsef(t, ok, "expected the decoder to return false after it was fully drained")
+	assert.NoError(t, s.Err())
+
+	d, ok := s.(*decoder)
+	if !ok {
+		t.Fatal("Streamer is not a decoder")
+	}
+
+	assert.Equal(t, header{
+		RiffMark:      [4]byte{'R', 'I', 'F', 'F'},
+		FileSize:      56, // without the riff mark and file size
+		WaveMark:      [4]byte{'W', 'A', 'V', 'E'},
+		FmtMark:       [4]byte{'f', 'm', 't', ' '},
+		FormatSize:    16,
+		FormatType:    1, // 1 = PCM
+		NumChans:      2,
+		SampleRate:    44100,
+		ByteRate:      176400, // 44100 * 2 bytes/sample precision * 2 channels = 176400 bytes/sec
+		BytesPerFrame: 4,      // 2 bytes/sample precision * 2 channels = 4 bytes/frame
+		BitsPerSample: 16,     // 2 bytes/sample precision = 16 bits/sample
+		DataMark:      [4]byte{'d', 'a', 't', 'a'},
+		DataSize:      20, // 5 samples * 2 bytes/sample precision * 2 channels = 20 bytes
+	}, d.h)
+}

wav/encode.go

@@ -81,7 +81,7 @@ func Encode(w io.WriteSeeker, s beep.Streamer, format beep.Format) (err error) {
 	}
 
 	// finalize header
-	h.FileSize = int32(44 + written) // 44 is the size of the header
+	h.FileSize = int32(44 - 8 + written) // 44-8 is the size of the header without RIFF signature and the length of the RIFF chunk
 	h.DataSize = int32(written)
 	if _, err := w.Seek(0, io.SeekStart); err != nil {
 		return err

wav/encode_test.go

@@ -0,0 +1,71 @@
+package wav
+
+import (
+	"github.com/gopxl/beep"
+	"github.com/orcaman/writerseeker"
+	"github.com/stretchr/testify/assert"
+	"testing"
+)
+
+func TestEncode(t *testing.T) {
+	var f = beep.Format{
+		SampleRate:  44100,
+		NumChannels: 2,
+		Precision:   2,
+	}
+	var w writerseeker.WriterSeeker
+	var s = beep.Silence(5)
+
+	err := Encode(&w, s, f)
+	if err != nil {
+		t.Fatalf("encoding failed with error: %v", err)
+	}
+
+	r := w.BytesReader()
+	expectedWrittenSize := 44 /* header length */ + 5*f.Precision*f.NumChannels /* number of samples * bytes per sample * number of channels */
+	assert.Equal(t, expectedWrittenSize, r.Len(), "the encoded file doesn't have the right size")
+
+	encoded := make([]byte, r.Len())
+	_, err = w.Reader().Read(encoded)
+	if err != nil {
+		t.Fatalf("failed reading the buffer: %v", err)
+	}
+
+	// Everything is encoded using little endian.
+	assert.Equal(t, []byte{
+		// Riff mark
+		'R', 'I', 'F', 'F',
+		// File size without riff mark and file size
+		0x38, 0x00, 0x00, 0x00, // 56 bytes
+		// Wave mark
+		'W', 'A', 'V', 'E',
+
+		// Fmt mark
+		'f', 'm', 't', ' ',
+		// Format chunk size
+		0x10, 0x00, 0x00, 0x00, // 16 bytes
+		// Format type
+		0x01, 0x00, // 1 = PCM
+		// Number of channels,
+		0x02, 0x00,
+		// Sample rate
+		0x44, 0xAC, 0x00, 0x00, // 44100 samples/sec
+		// Byte rate
+		0x10, 0xB1, 0x02, 0x00, // 44100 * 2 bytes/sample precision * 2 channels = 176400 bytes/sec
+		// Bytes per frame
+		0x04, 0x00, // 2 bytes/sample precision * 2 channels = 4 bytes/frame
+		// Bits per sample
+		0x10, 0x00, // 2 bytes/sample precision = 16 bits/sample
+
+		// Data mark
+		'd', 'a', 't', 'a',
+		// Data size
+		0x14, 0x00, 0x00, 0x00, // 5 samples * 2 bytes/sample precision * 2 channels = 20 bytes
+		// Data
+		0x00, 0x00, 0x00, 0x00,
+		0x00, 0x00, 0x00, 0x00,
+		0x00, 0x00, 0x00, 0x00,
+		0x00, 0x00, 0x00, 0x00,
+		0x00, 0x00, 0x00, 0x00,
+	}, encoded, "the encoded file isn't formatted as expected")
+}