From c496d94047970e74bbcf5fd0a33935ca533fa343 Mon Sep 17 00:00:00 2001
From: Hajime Hoshi <hajimehoshi@gmail.com>
Date: Sat, 17 Jun 2017 19:33:49 +0900
Subject: [PATCH] audio/mp3: Remove isEOF

---
 audio/mp3/decode_notjs.go | 14 +++++---------
 audio/mp3/l3.go           | 17 +++++++++--------
 audio/mp3/read.go         |  3 +++
 3 files changed, 17 insertions(+), 17 deletions(-)

diff --git a/audio/mp3/decode_notjs.go b/audio/mp3/decode_notjs.go
index a6dd1eeb0..3c272708f 100644
--- a/audio/mp3/decode_notjs.go
+++ b/audio/mp3/decode_notjs.go
@@ -17,6 +17,7 @@
 package mp3
 
 import (
+	"errors"
 	"io"
 )
 
@@ -113,22 +114,17 @@ func getBytes(buf []int) (int, error) {
 	return len(buf), nil
 }
 
-func isEOF() bool {
-	if len(readerCache) == 0 && readerEOF {
-		return true
-	}
-	return false
-}
-
 func getFilepos() int {
 	return readerPos
 }
 
+var eof = errors.New("mp3: expected EOF")
+
 func decode(r io.Reader, w io.Writer) error {
 	// TODO: Decoder should know number of channels
 	reader = r
 	writer = w
-	for !isEOF() {
+	for {
 		f, err := readFrame()
 		if err == nil {
 			if err := f.decodeL3(); err != nil {
@@ -136,7 +132,7 @@ func decode(r io.Reader, w io.Writer) error {
 			}
 			continue
 		}
-		if isEOF() {
+		if err == eof {
 			break
 		}
 		return err
diff --git a/audio/mp3/l3.go b/audio/mp3/l3.go
index 378f019d7..51ecfdf85 100644
--- a/audio/mp3/l3.go
+++ b/audio/mp3/l3.go
@@ -378,20 +378,22 @@ func (f *frame) l3Antialias(gr int, ch int) {
 var store = [2][32][18]float32{}
 
 func (f *frame) l3HybridSynthesis(gr int, ch int) {
-	for sb := 0; sb < 32; sb++ { /* Loop through all 32 subbands */
-		/* Determine blocktype for this subband */
+	// Loop through all 32 subbands
+	for sb := 0; sb < 32; sb++ {
+		// Determine blocktype for this subband
 		bt := int(f.sideInfo.block_type[gr][ch])
 		if (f.sideInfo.win_switch_flag[gr][ch] == 1) &&
 			(f.sideInfo.mixed_block_flag[gr][ch] == 1) && (sb < 2) {
 			bt = 0
 		}
-		/* Do the inverse modified DCT and windowing */
+		// Do the inverse modified DCT and windowing
 		in := make([]float32, 18)
 		for i := range in {
 			in[i] = f.mainData.is[gr][ch][sb*18+i]
 		}
 		rawout := imdctWin(in, bt)
-		for i := 0; i < 18; i++ { /* Overlapp add with stored vector into main_data vector */
+		// Overlapp add with stored vector into main_data vector
+		for i := 0; i < 18; i++ {
 			f.mainData.is[gr][ch][sb*18+i] = rawout[i] + store[ch][sb][i]
 			store[ch][sb][i] = rawout[i+18]
 		}
@@ -406,10 +408,7 @@ func (f *frame) l3FrequencyInversion(gr int, ch int) {
 	}
 }
 
-var (
-	g_synth_n_win = [64][32]float32{}
-	v_vec         = [2][1024]float32{}
-)
+var g_synth_n_win = [64][32]float32{}
 
 func init() {
 	for i := 0; i < 64; i++ {
@@ -551,6 +550,8 @@ var g_synth_dtbl = [512]float32{
 	0.000015259, 0.000015259, 0.000015259, 0.000015259,
 }
 
+var v_vec = [2][1024]float32{}
+
 func (f *frame) l3SubbandSynthesis(gr int, ch int, out []uint32) {
 	u_vec := make([]float32, 512)
 	s_vec := make([]float32, 32)
diff --git a/audio/mp3/read.go b/audio/mp3/read.go
index 3b6e0ebc5..5fb4a9c90 100644
--- a/audio/mp3/read.go
+++ b/audio/mp3/read.go
@@ -97,6 +97,9 @@ func (f *frame) readHeader() error {
 	}
 	if n < 4 {
 		if err == io.EOF {
+			if n == 0 {
+				return eof
+			}
 			return fmt.Errorf("mp3: unexpected EOF at readHeader")
 		}
 		return err