ADPCM: removed capAdd16 no longer used

stream/adpcm/adpcm.go

@@ -36,7 +36,6 @@ import (
 	"bytes"
 	"encoding/binary"
 	"fmt"
-	"math"
 )
 
 // Encoder is used to encode to ADPCM from PCM data.
@@ -182,19 +181,6 @@ func (d *Decoder) decodeSample(nibble byte) int16 {
 	return d.pred
 }
 
-// capAdd16 adds two int16s together and caps at max/min int16 instead of overflowing
-func capAdd16(a, b int16) int16 {
-	c := int32(a) + int32(b)
-	switch {
-	case c < math.MinInt16:
-		return math.MinInt16
-	case c > math.MaxInt16:
-		return math.MaxInt16
-	default:
-		return int16(c)
-	}
-}
-
 // calcHead sets the state for the encoder by running the first sample through
 // the encoder, and writing the first sample
 func (e *Encoder) calcHead(sample []byte) error {