http://netty.io/netty-all/: Netty is an asynchronous event-driven network application framework for rapid development of maintainable high performance protocol servers and clients. (The Netty Project) 
public class io.netty.handler.codec.protobuf.ProtobufVarint32FrameDecoder extends io.netty.handler.codec.ByteToMessageDecoder
  minor version: 0
  major version: 59
  flags: flags: (0x0021) ACC_PUBLIC, ACC_SUPER
  this_class: io.netty.handler.codec.protobuf.ProtobufVarint32FrameDecoder
  super_class: io.netty.handler.codec.ByteToMessageDecoder
{
  public void <init>();
    descriptor: ()V
    flags: (0x0001) ACC_PUBLIC
    Code:
      stack=1, locals=1, args_size=1
        start local 0 // io.netty.handler.codec.protobuf.ProtobufVarint32FrameDecoder this
         0: .line 43
            aload 0 /* this */
            invokespecial io.netty.handler.codec.ByteToMessageDecoder.<init>:()V
            return
        end local 0 // io.netty.handler.codec.protobuf.ProtobufVarint32FrameDecoder this
      LocalVariableTable:
        Start  End  Slot  Name  Signature
            0    1     0  this  Lio/netty/handler/codec/protobuf/ProtobufVarint32FrameDecoder;

  protected void decode(io.netty.channel.ChannelHandlerContext, io.netty.buffer.ByteBuf, java.util.List<java.lang.Object>);
    descriptor: (Lio/netty/channel/ChannelHandlerContext;Lio/netty/buffer/ByteBuf;Ljava/util/List;)V
    flags: (0x0004) ACC_PROTECTED
    Code:
      stack=5, locals=6, args_size=4
        start local 0 // io.netty.handler.codec.protobuf.ProtobufVarint32FrameDecoder this
        start local 1 // io.netty.channel.ChannelHandlerContext ctx
        start local 2 // io.netty.buffer.ByteBuf in
        start local 3 // java.util.List out
         0: .line 51
            aload 2 /* in */
            invokevirtual io.netty.buffer.ByteBuf.markReaderIndex:()Lio/netty/buffer/ByteBuf;
            pop
         1: .line 52
            aload 2 /* in */
            invokevirtual io.netty.buffer.ByteBuf.readerIndex:()I
            istore 4 /* preIndex */
        start local 4 // int preIndex
         2: .line 53
            aload 2 /* in */
            invokestatic io.netty.handler.codec.protobuf.ProtobufVarint32FrameDecoder.readRawVarint32:(Lio/netty/buffer/ByteBuf;)I
            istore 5 /* length */
        start local 5 // int length
         3: .line 54
            iload 4 /* preIndex */
            aload 2 /* in */
            invokevirtual io.netty.buffer.ByteBuf.readerIndex:()I
            if_icmpne 5
         4: .line 55
            return
         5: .line 57
      StackMap locals: int int
      StackMap stack:
            iload 5 /* length */
            ifge 7
         6: .line 58
            new io.netty.handler.codec.CorruptedFrameException
            dup
            new java.lang.StringBuilder
            dup
            ldc "negative length: "
            invokespecial java.lang.StringBuilder.<init>:(Ljava/lang/String;)V
            iload 5 /* length */
            invokevirtual java.lang.StringBuilder.append:(I)Ljava/lang/StringBuilder;
            invokevirtual java.lang.StringBuilder.toString:()Ljava/lang/String;
            invokespecial io.netty.handler.codec.CorruptedFrameException.<init>:(Ljava/lang/String;)V
            athrow
         7: .line 61
      StackMap locals:
      StackMap stack:
            aload 2 /* in */
            invokevirtual io.netty.buffer.ByteBuf.readableBytes:()I
            iload 5 /* length */
            if_icmpge 10
         8: .line 62
            aload 2 /* in */
            invokevirtual io.netty.buffer.ByteBuf.resetReaderIndex:()Lio/netty/buffer/ByteBuf;
            pop
         9: .line 63
            goto 11
        10: .line 64
      StackMap locals:
      StackMap stack:
            aload 3 /* out */
            aload 2 /* in */
            iload 5 /* length */
            invokevirtual io.netty.buffer.ByteBuf.readRetainedSlice:(I)Lio/netty/buffer/ByteBuf;
            invokeinterface java.util.List.add:(Ljava/lang/Object;)Z
            pop
        11: .line 66
      StackMap locals:
      StackMap stack:
            return
        end local 5 // int length
        end local 4 // int preIndex
        end local 3 // java.util.List out
        end local 2 // io.netty.buffer.ByteBuf in
        end local 1 // io.netty.channel.ChannelHandlerContext ctx
        end local 0 // io.netty.handler.codec.protobuf.ProtobufVarint32FrameDecoder this
      LocalVariableTable:
        Start  End  Slot      Name  Signature
            0   12     0      this  Lio/netty/handler/codec/protobuf/ProtobufVarint32FrameDecoder;
            0   12     1       ctx  Lio/netty/channel/ChannelHandlerContext;
            0   12     2        in  Lio/netty/buffer/ByteBuf;
            0   12     3       out  Ljava/util/List<Ljava/lang/Object;>;
            2   12     4  preIndex  I
            3   12     5    length  I
    Exceptions:
      throws java.lang.Exception
    Signature: (Lio/netty/channel/ChannelHandlerContext;Lio/netty/buffer/ByteBuf;Ljava/util/List<Ljava/lang/Object;>;)V
    MethodParameters:
      Name  Flags
      ctx   
      in    
      out   

  private static int readRawVarint32(io.netty.buffer.ByteBuf);
    descriptor: (Lio/netty/buffer/ByteBuf;)I
    flags: (0x000a) ACC_PRIVATE, ACC_STATIC
    Code:
      stack=3, locals=3, args_size=1
        start local 0 // io.netty.buffer.ByteBuf buffer
         0: .line 74
            aload 0 /* buffer */
            invokevirtual io.netty.buffer.ByteBuf.isReadable:()Z
            ifne 2
         1: .line 75
            iconst_0
            ireturn
         2: .line 77
      StackMap locals:
      StackMap stack:
            aload 0 /* buffer */
            invokevirtual io.netty.buffer.ByteBuf.markReaderIndex:()Lio/netty/buffer/ByteBuf;
            pop
         3: .line 78
            aload 0 /* buffer */
            invokevirtual io.netty.buffer.ByteBuf.readByte:()B
            istore 1 /* tmp */
        start local 1 // byte tmp
         4: .line 79
            iload 1 /* tmp */
            iflt 6
         5: .line 80
            iload 1 /* tmp */
            ireturn
         6: .line 82
      StackMap locals: int
      StackMap stack:
            iload 1 /* tmp */
            bipush 127
            iand
            istore 2 /* result */
        start local 2 // int result
         7: .line 83
            aload 0 /* buffer */
            invokevirtual io.netty.buffer.ByteBuf.isReadable:()Z
            ifne 10
         8: .line 84
            aload 0 /* buffer */
            invokevirtual io.netty.buffer.ByteBuf.resetReaderIndex:()Lio/netty/buffer/ByteBuf;
            pop
         9: .line 85
            iconst_0
            ireturn
        10: .line 87
      StackMap locals: int
      StackMap stack:
            aload 0 /* buffer */
            invokevirtual io.netty.buffer.ByteBuf.readByte:()B
            dup
            istore 1 /* tmp */
            iflt 13
        11: .line 88
            iload 2 /* result */
            iload 1 /* tmp */
            bipush 7
            ishl
            ior
            istore 2 /* result */
        12: .line 89
            goto 34
        13: .line 90
      StackMap locals:
      StackMap stack:
            iload 2 /* result */
            iload 1 /* tmp */
            bipush 127
            iand
            bipush 7
            ishl
            ior
            istore 2 /* result */
        14: .line 91
            aload 0 /* buffer */
            invokevirtual io.netty.buffer.ByteBuf.isReadable:()Z
            ifne 17
        15: .line 92
            aload 0 /* buffer */
            invokevirtual io.netty.buffer.ByteBuf.resetReaderIndex:()Lio/netty/buffer/ByteBuf;
            pop
        16: .line 93
            iconst_0
            ireturn
        17: .line 95
      StackMap locals:
      StackMap stack:
            aload 0 /* buffer */
            invokevirtual io.netty.buffer.ByteBuf.readByte:()B
            dup
            istore 1 /* tmp */
            iflt 20
        18: .line 96
            iload 2 /* result */
            iload 1 /* tmp */
            bipush 14
            ishl
            ior
            istore 2 /* result */
        19: .line 97
            goto 34
        20: .line 98
      StackMap locals:
      StackMap stack:
            iload 2 /* result */
            iload 1 /* tmp */
            bipush 127
            iand
            bipush 14
            ishl
            ior
            istore 2 /* result */
        21: .line 99
            aload 0 /* buffer */
            invokevirtual io.netty.buffer.ByteBuf.isReadable:()Z
            ifne 24
        22: .line 100
            aload 0 /* buffer */
            invokevirtual io.netty.buffer.ByteBuf.resetReaderIndex:()Lio/netty/buffer/ByteBuf;
            pop
        23: .line 101
            iconst_0
            ireturn
        24: .line 103
      StackMap locals:
      StackMap stack:
            aload 0 /* buffer */
            invokevirtual io.netty.buffer.ByteBuf.readByte:()B
            dup
            istore 1 /* tmp */
            iflt 27
        25: .line 104
            iload 2 /* result */
            iload 1 /* tmp */
            bipush 21
            ishl
            ior
            istore 2 /* result */
        26: .line 105
            goto 34
        27: .line 106
      StackMap locals:
      StackMap stack:
            iload 2 /* result */
            iload 1 /* tmp */
            bipush 127
            iand
            bipush 21
            ishl
            ior
            istore 2 /* result */
        28: .line 107
            aload 0 /* buffer */
            invokevirtual io.netty.buffer.ByteBuf.isReadable:()Z
            ifne 31
        29: .line 108
            aload 0 /* buffer */
            invokevirtual io.netty.buffer.ByteBuf.resetReaderIndex:()Lio/netty/buffer/ByteBuf;
            pop
        30: .line 109
            iconst_0
            ireturn
        31: .line 111
      StackMap locals:
      StackMap stack:
            iload 2 /* result */
            aload 0 /* buffer */
            invokevirtual io.netty.buffer.ByteBuf.readByte:()B
            dup
            istore 1 /* tmp */
            bipush 28
            ishl
            ior
            istore 2 /* result */
        32: .line 112
            iload 1 /* tmp */
            ifge 34
        33: .line 113
            new io.netty.handler.codec.CorruptedFrameException
            dup
            ldc "malformed varint."
            invokespecial io.netty.handler.codec.CorruptedFrameException.<init>:(Ljava/lang/String;)V
            athrow
        34: .line 118
      StackMap locals:
      StackMap stack:
            iload 2 /* result */
            ireturn
        end local 2 // int result
        end local 1 // byte tmp
        end local 0 // io.netty.buffer.ByteBuf buffer
      LocalVariableTable:
        Start  End  Slot    Name  Signature
            0   35     0  buffer  Lio/netty/buffer/ByteBuf;
            4   35     1     tmp  B
            7   35     2  result  I
    MethodParameters:
        Name  Flags
      buffer  
}
SourceFile: "ProtobufVarint32FrameDecoder.java"