Fix integer overflow during unfolding of the rice residual

mewkiz · Oct 24, 2023 · c51ad5c · c51ad5c
1 parent 0b08a2f
commit c51ad5c
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Showing 2 changed files with 4 additions and 4 deletions.
diff --git a/frame/subframe.go b/frame/subframe.go
@@ -443,10 +443,10 @@ func (subframe *Subframe) decodeRiceResidual(br *bits.Reader, k uint) error {
 	if err != nil {
 		return unexpected(err)
 	}
-	residual := int32(high<<k | low)
+	folded := uint32(high<<k | low)
 
 	// ZigZag decode.
-	residual = bits.ZigZag(residual)
+	residual := bits.ZigZag(folded)
 	subframe.Samples = append(subframe.Samples, residual)
 
 	return nil

diff --git a/internal/bits/zigzag.go b/internal/bits/zigzag.go
@@ -14,6 +14,6 @@ package bits
 //	6 =>  3
 //
 // ref: https://developers.google.com/protocol-buffers/docs/encoding
-func ZigZag(x int32) int32 {
-	return x>>1 ^ -(x & 1)
+func ZigZag(x uint32) int32 {
+	return int32(x>>1) ^ -int32(x&1)
 }