nativeaudio

commit b99d4924dc35ce789e97cfb932a4f146377061ce
parent 578749db237b7d4e186be0d9267ffde33a46e080
Author: Jack Mordaunt <jackmordaunt.dev@gmail.com>
Date:   Fri,  3 May 2024 16:51:50 +0800

nativeaudio: [macos] allow requested bytes to exceed audio data

A lovely undocumented feature of this api. It seems like we need to
handle the caller asking for more than we have.

Signed-off-by: Jack Mordaunt <jackmordaunt.dev@gmail.com>

Diffstat:
M
audio_macos.go
 | 
18
+++++++++++++++---

1 file changed, 15 insertions(+), 3 deletions(-)
diff --git a/audio_macos.go b/audio_macos.go
@@ -535,14 +535,26 @@ func AudioFileReadProcImpl(
 	buffer unsafe.Pointer,
 	actualCount *C.UInt32,
 ) C.OSStatus {
+	pos := int(inPosition)
+	req := int(requestCount)
+	end := pos + req
+
 	inBuf := *(*[]byte)(inClientData)
 
 	// Assuming the the out buffer is sized to contain the requested number of bytes.
 	// This is not memory we control.
-	outBuf := unsafe.Slice((*byte)(buffer), requestCount)
+	outBuf := unsafe.Slice((*byte)(buffer), req)
+
+	dst := outBuf[:req]
+
+	// It seems like the requested amount is allowed to exceed the
+	// actual size of the audio data. In that case we need to bound
+	// it by the length of the audio data.
+	if end > len(inBuf) {
+		end = len(inBuf)
+	}
 
-	dst := outBuf[:int(requestCount)]
-	src := inBuf[int(inPosition) : int(inPosition)+int(requestCount)]
+	src := inBuf[pos:end]
 
 	n := copy(dst, src)