From 960d41cb4f238e5383ef8bca5107095ef2e530c5 Mon Sep 17 00:00:00 2001
From: Saxon <saxon@ausocean.org>
Date: Sun, 8 Sep 2019 13:31:10 +0930
Subject: [PATCH] codec/h264/h264dec/cavlc.go: removed redundant if checks in
 parseLevelInformation

---
 codec/h264/h264dec/cavlc.go | 130 +++++++++++++++++-------------------
 1 file changed, 63 insertions(+), 67 deletions(-)

diff --git a/codec/h264/h264dec/cavlc.go b/codec/h264/h264dec/cavlc.go
index 0dcbc64b..820ec67c 100644
--- a/codec/h264/h264dec/cavlc.go
+++ b/codec/h264/h264dec/cavlc.go
@@ -51,18 +51,16 @@ func parseLevelPrefix(br *bits.BitReader) (int, error) {
 func parseLevelInformation(br *bits.BitReader, totalCoeff, trailingOnes int) ([]int, error) {
 	var levelVal []int
 	var i int
-	if trailingOnes != 0 {
-		for ; i < trailingOnes; i++ {
-			b, err := br.ReadBits(1)
-			if err != nil {
-				return nil, fmt.Errorf("could not read trailing_ones_sign_flag, failed with error: %v", err)
-			}
-			if b == 0 {
-				levelVal = append(levelVal, 1)
-				continue
-			}
-			levelVal = append(levelVal, -1)
+	for ; i < trailingOnes; i++ {
+		b, err := br.ReadBits(1)
+		if err != nil {
+			return nil, fmt.Errorf("could not read trailing_ones_sign_flag, failed with error: %v", err)
 		}
+		if b == 0 {
+			levelVal = append(levelVal, 1)
+			continue
+		}
+		levelVal = append(levelVal, -1)
 	}
 
 	var suffixLen int
@@ -75,63 +73,61 @@ func parseLevelInformation(br *bits.BitReader, totalCoeff, trailingOnes int) ([]
 		return nil, errors.New("invalid TotalCoeff and TrailingOnes combination")
 	}
 
-	if totalCoeff-trailingOnes != 0 {
-		for j := 0; j < totalCoeff-trailingOnes; j++ {
-			levelPrefix, err := parseLevelPrefix(br)
-			if err != nil {
-				return nil, fmt.Errorf("could not parse level prefix, failed with error: %v", err)
-			}
-
-			var levelSuffixSize int
-			switch {
-			case levelPrefix == 14 && suffixLen == 0:
-				levelSuffixSize = 4
-			case levelPrefix >= 15:
-				levelSuffixSize = levelPrefix - 3
-			default:
-				levelSuffixSize = suffixLen
-			}
-
-			var levelSuffix int
-			if levelSuffixSize > 0 {
-				b, err := br.ReadBits(levelSuffixSize)
-				if err != nil {
-					return nil, fmt.Errorf("could not parse levelSuffix, failed with error: %v", err)
-				}
-				levelSuffix = int(b)
-			} else {
-				levelSuffix = 0
-			}
-
-			levelCode := (mini(15, levelPrefix) << uint(suffixLen)) + levelSuffix
-
-			if levelPrefix >= 15 && suffixLen == 0 {
-				levelCode += 15
-			}
-
-			if levelPrefix >= 16 {
-				levelCode += (1 << uint(levelPrefix-3)) - 4096
-			}
-
-			if i == trailingOnes && trailingOnes < 3 {
-				levelCode += 2
-			}
-
-			if levelCode%2 == 0 {
-				levelVal = append(levelVal, (levelCode+2)>>1)
-			} else {
-				levelVal = append(levelVal, (-levelCode-1)>>1)
-			}
-
-			if suffixLen == 0 {
-				suffixLen = 1
-			}
-
-			if absi(levelVal[i]) > (3<<uint(suffixLen-1)) && suffixLen < 6 {
-				suffixLen++
-			}
-			i++
+	for j := 0; j < totalCoeff-trailingOnes; j++ {
+		levelPrefix, err := parseLevelPrefix(br)
+		if err != nil {
+			return nil, fmt.Errorf("could not parse level prefix, failed with error: %v", err)
 		}
+
+		var levelSuffixSize int
+		switch {
+		case levelPrefix == 14 && suffixLen == 0:
+			levelSuffixSize = 4
+		case levelPrefix >= 15:
+			levelSuffixSize = levelPrefix - 3
+		default:
+			levelSuffixSize = suffixLen
+		}
+
+		var levelSuffix int
+		if levelSuffixSize > 0 {
+			b, err := br.ReadBits(levelSuffixSize)
+			if err != nil {
+				return nil, fmt.Errorf("could not parse levelSuffix, failed with error: %v", err)
+			}
+			levelSuffix = int(b)
+		} else {
+			levelSuffix = 0
+		}
+
+		levelCode := (mini(15, levelPrefix) << uint(suffixLen)) + levelSuffix
+
+		if levelPrefix >= 15 && suffixLen == 0 {
+			levelCode += 15
+		}
+
+		if levelPrefix >= 16 {
+			levelCode += (1 << uint(levelPrefix-3)) - 4096
+		}
+
+		if i == trailingOnes && trailingOnes < 3 {
+			levelCode += 2
+		}
+
+		if levelCode%2 == 0 {
+			levelVal = append(levelVal, (levelCode+2)>>1)
+		} else {
+			levelVal = append(levelVal, (-levelCode-1)>>1)
+		}
+
+		if suffixLen == 0 {
+			suffixLen = 1
+		}
+
+		if absi(levelVal[i]) > (3<<uint(suffixLen-1)) && suffixLen < 6 {
+			suffixLen++
+		}
+		i++
 	}
 	return levelVal, nil
 }