From e5fbcd50de6ca3024db587b80e2d33c424e80e02 Mon Sep 17 00:00:00 2001
From: Hajime Hoshi <hajimehoshi@gmail.com>
Date: Sat, 17 Jun 2017 00:34:54 +0900
Subject: [PATCH] audio/mp3: Refactoring getByte(s)

---
 audio/mp3/decode_notjs.go | 13 ++++++-------
 audio/mp3/maindata.go     | 15 +++++++++------
 audio/mp3/sideinfo.go     |  8 +++++---
 3 files changed, 20 insertions(+), 16 deletions(-)

diff --git a/audio/mp3/decode_notjs.go b/audio/mp3/decode_notjs.go
index 76f0a0e50..6ee24768c 100644
--- a/audio/mp3/decode_notjs.go
+++ b/audio/mp3/decode_notjs.go
@@ -59,7 +59,7 @@ func Get_Byte() C.unsigned {
 		}
 		readerCache = buf[:n]
 	}
-	if readerEOF {
+	if len(readerCache) == 0 {
 		return eof
 	}
 	b := readerCache[0]
@@ -68,16 +68,15 @@ func Get_Byte() C.unsigned {
 	return C.unsigned(b)
 }
 
-func getBytes(num int) ([]int, error) {
-	r := make([]int, num)
-	for i := 0; i < num; i++ {
+func getBytes(buf []int) (int, error) {
+	for i := range buf {
 		v := Get_Byte()
 		if v == eof {
-			return r, io.EOF
+			return i, io.EOF
 		}
-		r[i] = int(v)
+		buf[i] = int(v)
 	}
-	return r, nil
+	return len(buf), nil
 }
 
 //export Get_Filepos
diff --git a/audio/mp3/maindata.go b/audio/mp3/maindata.go
index 451994a4e..553bdc212 100644
--- a/audio/mp3/maindata.go
+++ b/audio/mp3/maindata.go
@@ -25,6 +25,7 @@ import "C"
 
 import (
 	"fmt"
+	"io"
 )
 
 var mpeg1_scalefac_sizes = [16][2]int{
@@ -183,12 +184,13 @@ func getMainData(size int, begin int) int {
 		// No,there is not,so we skip decoding this frame,but we have to
 		// read the main_data bits from the bitstream in case they are needed
 		// for decoding the next frame.
-		b, err := getBytes(size)
-		if err != nil {
+		buf := make([]int, size)
+		n, err := getBytes(buf)
+		if err != nil && err != io.EOF {
 			g_error = err
 			return C.ERROR
 		}
-		copy(theMainDataBytes.vec[theMainDataBytes.top:], b)
+		copy(theMainDataBytes.vec[theMainDataBytes.top:], buf[:n])
 		/* Set up pointers */
 		theMainDataBytes.ptr = theMainDataBytes.vec[0:]
 		theMainDataBytes.pos = 0
@@ -201,12 +203,13 @@ func getMainData(size int, begin int) int {
 		theMainDataBytes.vec[i] = theMainDataBytes.vec[theMainDataBytes.top-begin+i]
 	}
 	/* Read the main_data from file */
-	b, err := getBytes(int(size))
-	if err != nil {
+	buf := make([]int, size)
+	n, err := getBytes(buf)
+	if err != nil && err != io.EOF {
 		g_error = err
 		return C.ERROR
 	}
-	copy(theMainDataBytes.vec[begin:], b)
+	copy(theMainDataBytes.vec[begin:], buf[:n])
 	/* Set up pointers */
 	theMainDataBytes.ptr = theMainDataBytes.vec[0:]
 	theMainDataBytes.pos = 0
diff --git a/audio/mp3/sideinfo.go b/audio/mp3/sideinfo.go
index dab63c221..7ed3fafad 100644
--- a/audio/mp3/sideinfo.go
+++ b/audio/mp3/sideinfo.go
@@ -24,6 +24,7 @@ import "C"
 
 import (
 	"fmt"
+	"io"
 )
 
 var g_mpeg1_bitrates = [3][15]int{
@@ -138,13 +139,14 @@ type sideInfo struct {
 var theSideInfo sideInfo
 
 func getSideinfo(size int) {
-	var err error
-	theSideInfo.vec, err = getBytes(int(size))
-	if err != nil {
+	buf := make([]int, size)
+	n, err := getBytes(buf)
+	if err != nil && err != io.EOF {
 		g_error = fmt.Errorf("mp3: couldn't read sideinfo %d bytes at pos %d: %v",
 			size, Get_Filepos(), err)
 		return
 	}
+	theSideInfo.vec = buf[:n]
 	theSideInfo.idx = 0
 }