public class io.netty.handler.codec.compression.JZlibDecoder extends io.netty.handler.codec.compression.ZlibDecoder
  minor version: 0
  major version: 59
  flags: flags: (0x0021) ACC_PUBLIC, ACC_SUPER
  this_class: io.netty.handler.codec.compression.JZlibDecoder
  super_class: io.netty.handler.codec.compression.ZlibDecoder
{
  private final com.jcraft.jzlib.Inflater z;
    descriptor: Lcom/jcraft/jzlib/Inflater;
    flags: (0x0012) ACC_PRIVATE, ACC_FINAL

  private byte[] dictionary;
    descriptor: [B
    flags: (0x0002) ACC_PRIVATE

  private volatile boolean finished;
    descriptor: Z
    flags: (0x0042) ACC_PRIVATE, ACC_VOLATILE

  public void <init>();
    descriptor: ()V
    flags: (0x0001) ACC_PUBLIC
    Code:
      stack=2, locals=1, args_size=1
        start local 0 // io.netty.handler.codec.compression.JZlibDecoder this
         0: .line 37
            aload 0 /* this */
            getstatic io.netty.handler.codec.compression.ZlibWrapper.ZLIB:Lio/netty/handler/codec/compression/ZlibWrapper;
            invokespecial io.netty.handler.codec.compression.JZlibDecoder.<init>:(Lio/netty/handler/codec/compression/ZlibWrapper;)V
         1: .line 38
            return
        end local 0 // io.netty.handler.codec.compression.JZlibDecoder this
      LocalVariableTable:
        Start  End  Slot  Name  Signature
            0    2     0  this  Lio/netty/handler/codec/compression/JZlibDecoder;

  public void <init>(io.netty.handler.codec.compression.ZlibWrapper);
    descriptor: (Lio/netty/handler/codec/compression/ZlibWrapper;)V
    flags: (0x0001) ACC_PUBLIC
    Code:
      stack=3, locals=3, args_size=2
        start local 0 // io.netty.handler.codec.compression.JZlibDecoder this
        start local 1 // io.netty.handler.codec.compression.ZlibWrapper wrapper
         0: .line 45
            aload 0 /* this */
            invokespecial io.netty.handler.codec.compression.ZlibDecoder.<init>:()V
         1: .line 27
            aload 0 /* this */
            new com.jcraft.jzlib.Inflater
            dup
            invokespecial com.jcraft.jzlib.Inflater.<init>:()V
            putfield io.netty.handler.codec.compression.JZlibDecoder.z:Lcom/jcraft/jzlib/Inflater;
         2: .line 46
            aload 1 /* wrapper */
            ifnonnull 4
         3: .line 47
            new java.lang.NullPointerException
            dup
            ldc "wrapper"
            invokespecial java.lang.NullPointerException.<init>:(Ljava/lang/String;)V
            athrow
         4: .line 50
      StackMap locals: io.netty.handler.codec.compression.JZlibDecoder io.netty.handler.codec.compression.ZlibWrapper
      StackMap stack:
            aload 0 /* this */
            getfield io.netty.handler.codec.compression.JZlibDecoder.z:Lcom/jcraft/jzlib/Inflater;
            aload 1 /* wrapper */
            invokestatic io.netty.handler.codec.compression.ZlibUtil.convertWrapperType:(Lio/netty/handler/codec/compression/ZlibWrapper;)Lcom/jcraft/jzlib/JZlib$WrapperType;
            invokevirtual com.jcraft.jzlib.Inflater.init:(Lcom/jcraft/jzlib/JZlib$WrapperType;)I
            istore 2 /* resultCode */
        start local 2 // int resultCode
         5: .line 51
            iload 2 /* resultCode */
            ifeq 7
         6: .line 52
            aload 0 /* this */
            getfield io.netty.handler.codec.compression.JZlibDecoder.z:Lcom/jcraft/jzlib/Inflater;
            ldc "initialization failure"
            iload 2 /* resultCode */
            invokestatic io.netty.handler.codec.compression.ZlibUtil.fail:(Lcom/jcraft/jzlib/Inflater;Ljava/lang/String;I)V
         7: .line 54
      StackMap locals: int
      StackMap stack:
            return
        end local 2 // int resultCode
        end local 1 // io.netty.handler.codec.compression.ZlibWrapper wrapper
        end local 0 // io.netty.handler.codec.compression.JZlibDecoder this
      LocalVariableTable:
        Start  End  Slot        Name  Signature
            0    8     0        this  Lio/netty/handler/codec/compression/JZlibDecoder;
            0    8     1     wrapper  Lio/netty/handler/codec/compression/ZlibWrapper;
            5    8     2  resultCode  I
    MethodParameters:
         Name  Flags
      wrapper  

  public void <init>(byte[]);
    descriptor: ([B)V
    flags: (0x0001) ACC_PUBLIC
    Code:
      stack=3, locals=3, args_size=2
        start local 0 // io.netty.handler.codec.compression.JZlibDecoder this
        start local 1 // byte[] dictionary
         0: .line 63
            aload 0 /* this */
            invokespecial io.netty.handler.codec.compression.ZlibDecoder.<init>:()V
         1: .line 27
            aload 0 /* this */
            new com.jcraft.jzlib.Inflater
            dup
            invokespecial com.jcraft.jzlib.Inflater.<init>:()V
            putfield io.netty.handler.codec.compression.JZlibDecoder.z:Lcom/jcraft/jzlib/Inflater;
         2: .line 64
            aload 1 /* dictionary */
            ifnonnull 4
         3: .line 65
            new java.lang.NullPointerException
            dup
            ldc "dictionary"
            invokespecial java.lang.NullPointerException.<init>:(Ljava/lang/String;)V
            athrow
         4: .line 67
      StackMap locals: io.netty.handler.codec.compression.JZlibDecoder byte[]
      StackMap stack:
            aload 0 /* this */
            aload 1 /* dictionary */
            putfield io.netty.handler.codec.compression.JZlibDecoder.dictionary:[B
         5: .line 70
            aload 0 /* this */
            getfield io.netty.handler.codec.compression.JZlibDecoder.z:Lcom/jcraft/jzlib/Inflater;
            getstatic com.jcraft.jzlib.JZlib.W_ZLIB:Lcom/jcraft/jzlib/JZlib$WrapperType;
            invokevirtual com.jcraft.jzlib.Inflater.inflateInit:(Lcom/jcraft/jzlib/JZlib$WrapperType;)I
            istore 2 /* resultCode */
        start local 2 // int resultCode
         6: .line 71
            iload 2 /* resultCode */
            ifeq 8
         7: .line 72
            aload 0 /* this */
            getfield io.netty.handler.codec.compression.JZlibDecoder.z:Lcom/jcraft/jzlib/Inflater;
            ldc "initialization failure"
            iload 2 /* resultCode */
            invokestatic io.netty.handler.codec.compression.ZlibUtil.fail:(Lcom/jcraft/jzlib/Inflater;Ljava/lang/String;I)V
         8: .line 74
      StackMap locals: int
      StackMap stack:
            return
        end local 2 // int resultCode
        end local 1 // byte[] dictionary
        end local 0 // io.netty.handler.codec.compression.JZlibDecoder this
      LocalVariableTable:
        Start  End  Slot        Name  Signature
            0    9     0        this  Lio/netty/handler/codec/compression/JZlibDecoder;
            0    9     1  dictionary  [B
            6    9     2  resultCode  I
    MethodParameters:
            Name  Flags
      dictionary  

  public boolean isClosed();
    descriptor: ()Z
    flags: (0x0001) ACC_PUBLIC
    Code:
      stack=1, locals=1, args_size=1
        start local 0 // io.netty.handler.codec.compression.JZlibDecoder this
         0: .line 82
            aload 0 /* this */
            getfield io.netty.handler.codec.compression.JZlibDecoder.finished:Z
            ireturn
        end local 0 // io.netty.handler.codec.compression.JZlibDecoder this
      LocalVariableTable:
        Start  End  Slot  Name  Signature
            0    1     0  this  Lio/netty/handler/codec/compression/JZlibDecoder;

  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=3, locals=12, args_size=4
        start local 0 // io.netty.handler.codec.compression.JZlibDecoder 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 87
            aload 0 /* this */
            getfield io.netty.handler.codec.compression.JZlibDecoder.finished:Z
            ifeq 3
         1: .line 89
            aload 2 /* in */
            aload 2 /* in */
            invokevirtual io.netty.buffer.ByteBuf.readableBytes:()I
            invokevirtual io.netty.buffer.ByteBuf.skipBytes:(I)Lio/netty/buffer/ByteBuf;
            pop
         2: .line 90
            return
         3: .line 93
      StackMap locals:
      StackMap stack:
            aload 2 /* in */
            invokevirtual io.netty.buffer.ByteBuf.readableBytes:()I
            istore 4 /* inputLength */
        start local 4 // int inputLength
         4: .line 94
            iload 4 /* inputLength */
            ifne 6
         5: .line 95
            return
         6: .line 100
      StackMap locals: int
      StackMap stack:
            aload 0 /* this */
            getfield io.netty.handler.codec.compression.JZlibDecoder.z:Lcom/jcraft/jzlib/Inflater;
            iload 4 /* inputLength */
            putfield com.jcraft.jzlib.Inflater.avail_in:I
         7: .line 101
            aload 2 /* in */
            invokevirtual io.netty.buffer.ByteBuf.hasArray:()Z
            ifeq 11
         8: .line 102
            aload 0 /* this */
            getfield io.netty.handler.codec.compression.JZlibDecoder.z:Lcom/jcraft/jzlib/Inflater;
            aload 2 /* in */
            invokevirtual io.netty.buffer.ByteBuf.array:()[B
            putfield com.jcraft.jzlib.Inflater.next_in:[B
         9: .line 103
            aload 0 /* this */
            getfield io.netty.handler.codec.compression.JZlibDecoder.z:Lcom/jcraft/jzlib/Inflater;
            aload 2 /* in */
            invokevirtual io.netty.buffer.ByteBuf.arrayOffset:()I
            aload 2 /* in */
            invokevirtual io.netty.buffer.ByteBuf.readerIndex:()I
            iadd
            putfield com.jcraft.jzlib.Inflater.next_in_index:I
        10: .line 104
            goto 15
        11: .line 105
      StackMap locals:
      StackMap stack:
            iload 4 /* inputLength */
            newarray 8
            astore 5 /* array */
        start local 5 // byte[] array
        12: .line 106
            aload 2 /* in */
            aload 2 /* in */
            invokevirtual io.netty.buffer.ByteBuf.readerIndex:()I
            aload 5 /* array */
            invokevirtual io.netty.buffer.ByteBuf.getBytes:(I[B)Lio/netty/buffer/ByteBuf;
            pop
        13: .line 107
            aload 0 /* this */
            getfield io.netty.handler.codec.compression.JZlibDecoder.z:Lcom/jcraft/jzlib/Inflater;
            aload 5 /* array */
            putfield com.jcraft.jzlib.Inflater.next_in:[B
        14: .line 108
            aload 0 /* this */
            getfield io.netty.handler.codec.compression.JZlibDecoder.z:Lcom/jcraft/jzlib/Inflater;
            iconst_0
            putfield com.jcraft.jzlib.Inflater.next_in_index:I
        end local 5 // byte[] array
        15: .line 110
      StackMap locals:
      StackMap stack:
            aload 0 /* this */
            getfield io.netty.handler.codec.compression.JZlibDecoder.z:Lcom/jcraft/jzlib/Inflater;
            getfield com.jcraft.jzlib.Inflater.next_in_index:I
            istore 5 /* oldNextInIndex */
        start local 5 // int oldNextInIndex
        16: .line 113
            aload 1 /* ctx */
            invokeinterface io.netty.channel.ChannelHandlerContext.alloc:()Lio/netty/buffer/ByteBufAllocator;
            iload 4 /* inputLength */
            iconst_1
            ishl
            invokeinterface io.netty.buffer.ByteBufAllocator.heapBuffer:(I)Lio/netty/buffer/ByteBuf;
            astore 6 /* decompressed */
        start local 6 // io.netty.buffer.ByteBuf decompressed
        17: .line 117
      StackMap locals: int io.netty.buffer.ByteBuf
      StackMap stack:
            aload 6 /* decompressed */
            aload 0 /* this */
            getfield io.netty.handler.codec.compression.JZlibDecoder.z:Lcom/jcraft/jzlib/Inflater;
            getfield com.jcraft.jzlib.Inflater.avail_in:I
            iconst_1
            ishl
            invokevirtual io.netty.buffer.ByteBuf.ensureWritable:(I)Lio/netty/buffer/ByteBuf;
            pop
        18: .line 118
            aload 0 /* this */
            getfield io.netty.handler.codec.compression.JZlibDecoder.z:Lcom/jcraft/jzlib/Inflater;
            aload 6 /* decompressed */
            invokevirtual io.netty.buffer.ByteBuf.writableBytes:()I
            putfield com.jcraft.jzlib.Inflater.avail_out:I
        19: .line 119
            aload 0 /* this */
            getfield io.netty.handler.codec.compression.JZlibDecoder.z:Lcom/jcraft/jzlib/Inflater;
            aload 6 /* decompressed */
            invokevirtual io.netty.buffer.ByteBuf.array:()[B
            putfield com.jcraft.jzlib.Inflater.next_out:[B
        20: .line 120
            aload 0 /* this */
            getfield io.netty.handler.codec.compression.JZlibDecoder.z:Lcom/jcraft/jzlib/Inflater;
            aload 6 /* decompressed */
            invokevirtual io.netty.buffer.ByteBuf.arrayOffset:()I
            aload 6 /* decompressed */
            invokevirtual io.netty.buffer.ByteBuf.writerIndex:()I
            iadd
            putfield com.jcraft.jzlib.Inflater.next_out_index:I
        21: .line 121
            aload 0 /* this */
            getfield io.netty.handler.codec.compression.JZlibDecoder.z:Lcom/jcraft/jzlib/Inflater;
            getfield com.jcraft.jzlib.Inflater.next_out_index:I
            istore 7 /* oldNextOutIndex */
        start local 7 // int oldNextOutIndex
        22: .line 124
            aload 0 /* this */
            getfield io.netty.handler.codec.compression.JZlibDecoder.z:Lcom/jcraft/jzlib/Inflater;
            iconst_2
            invokevirtual com.jcraft.jzlib.Inflater.inflate:(I)I
            istore 8 /* resultCode */
        start local 8 // int resultCode
        23: .line 125
            aload 0 /* this */
            getfield io.netty.handler.codec.compression.JZlibDecoder.z:Lcom/jcraft/jzlib/Inflater;
            getfield com.jcraft.jzlib.Inflater.next_out_index:I
            iload 7 /* oldNextOutIndex */
            isub
            istore 9 /* outputLength */
        start local 9 // int outputLength
        24: .line 126
            iload 9 /* outputLength */
            ifle 26
        25: .line 127
            aload 6 /* decompressed */
            aload 6 /* decompressed */
            invokevirtual io.netty.buffer.ByteBuf.writerIndex:()I
            iload 9 /* outputLength */
            iadd
            invokevirtual io.netty.buffer.ByteBuf.writerIndex:(I)Lio/netty/buffer/ByteBuf;
            pop
        26: .line 130
      StackMap locals: int int int
      StackMap stack:
            iload 8 /* resultCode */
            tableswitch { // -5 - 2
                   -5: 38
                   -4: 40
                   -3: 40
                   -2: 40
                   -1: 40
                    0: 37
                    1: 34
                    2: 27
              default: 40
          }
        27: .line 132
      StackMap locals:
      StackMap stack:
            aload 0 /* this */
            getfield io.netty.handler.codec.compression.JZlibDecoder.dictionary:[B
            ifnonnull 30
        28: .line 133
            aload 0 /* this */
            getfield io.netty.handler.codec.compression.JZlibDecoder.z:Lcom/jcraft/jzlib/Inflater;
            ldc "decompression failure"
            iload 8 /* resultCode */
            invokestatic io.netty.handler.codec.compression.ZlibUtil.fail:(Lcom/jcraft/jzlib/Inflater;Ljava/lang/String;I)V
        29: .line 134
            goto 17
        30: .line 135
      StackMap locals:
      StackMap stack:
            aload 0 /* this */
            getfield io.netty.handler.codec.compression.JZlibDecoder.z:Lcom/jcraft/jzlib/Inflater;
            aload 0 /* this */
            getfield io.netty.handler.codec.compression.JZlibDecoder.dictionary:[B
            aload 0 /* this */
            getfield io.netty.handler.codec.compression.JZlibDecoder.dictionary:[B
            arraylength
            invokevirtual com.jcraft.jzlib.Inflater.inflateSetDictionary:([BI)I
            istore 8 /* resultCode */
        31: .line 136
            iload 8 /* resultCode */
            ifeq 17
        32: .line 137
            aload 0 /* this */
            getfield io.netty.handler.codec.compression.JZlibDecoder.z:Lcom/jcraft/jzlib/Inflater;
            ldc "failed to set the dictionary"
            iload 8 /* resultCode */
            invokestatic io.netty.handler.codec.compression.ZlibUtil.fail:(Lcom/jcraft/jzlib/Inflater;Ljava/lang/String;I)V
        33: .line 140
            goto 17
        34: .line 142
      StackMap locals:
      StackMap stack:
            aload 0 /* this */
            iconst_1
            putfield io.netty.handler.codec.compression.JZlibDecoder.finished:Z
        35: .line 143
            aload 0 /* this */
            getfield io.netty.handler.codec.compression.JZlibDecoder.z:Lcom/jcraft/jzlib/Inflater;
            invokevirtual com.jcraft.jzlib.Inflater.inflateEnd:()I
            pop
        36: .line 144
            goto 49
        37: .line 146
      StackMap locals:
      StackMap stack:
            goto 17
        38: .line 148
      StackMap locals:
      StackMap stack:
            aload 0 /* this */
            getfield io.netty.handler.codec.compression.JZlibDecoder.z:Lcom/jcraft/jzlib/Inflater;
            getfield com.jcraft.jzlib.Inflater.avail_in:I
            ifgt 17
        39: .line 149
            goto 49
        40: .line 153
      StackMap locals:
      StackMap stack:
            aload 0 /* this */
            getfield io.netty.handler.codec.compression.JZlibDecoder.z:Lcom/jcraft/jzlib/Inflater;
            ldc "decompression failure"
            iload 8 /* resultCode */
            invokestatic io.netty.handler.codec.compression.ZlibUtil.fail:(Lcom/jcraft/jzlib/Inflater;Ljava/lang/String;I)V
        end local 9 // int outputLength
        end local 8 // int resultCode
        end local 7 // int oldNextOutIndex
        41: .line 116
            goto 17
        42: .line 156
      StackMap locals: io.netty.handler.codec.compression.JZlibDecoder io.netty.channel.ChannelHandlerContext io.netty.buffer.ByteBuf java.util.List int int io.netty.buffer.ByteBuf
      StackMap stack: java.lang.Throwable
            astore 10
        43: .line 157
            aload 2 /* in */
            aload 0 /* this */
            getfield io.netty.handler.codec.compression.JZlibDecoder.z:Lcom/jcraft/jzlib/Inflater;
            getfield com.jcraft.jzlib.Inflater.next_in_index:I
            iload 5 /* oldNextInIndex */
            isub
            invokevirtual io.netty.buffer.ByteBuf.skipBytes:(I)Lio/netty/buffer/ByteBuf;
            pop
        44: .line 158
            aload 6 /* decompressed */
            invokevirtual io.netty.buffer.ByteBuf.isReadable:()Z
            ifeq 47
        45: .line 159
            aload 3 /* out */
            aload 6 /* decompressed */
            invokeinterface java.util.List.add:(Ljava/lang/Object;)Z
            pop
        46: .line 160
            goto 48
        47: .line 161
      StackMap locals: io.netty.handler.codec.compression.JZlibDecoder io.netty.channel.ChannelHandlerContext io.netty.buffer.ByteBuf java.util.List int int io.netty.buffer.ByteBuf top top top java.lang.Throwable
      StackMap stack:
            aload 6 /* decompressed */
            invokevirtual io.netty.buffer.ByteBuf.release:()Z
            pop
        48: .line 163
      StackMap locals:
      StackMap stack:
            aload 10
            athrow
        49: .line 157
      StackMap locals: io.netty.handler.codec.compression.JZlibDecoder io.netty.channel.ChannelHandlerContext io.netty.buffer.ByteBuf java.util.List int int io.netty.buffer.ByteBuf
      StackMap stack:
            aload 2 /* in */
            aload 0 /* this */
            getfield io.netty.handler.codec.compression.JZlibDecoder.z:Lcom/jcraft/jzlib/Inflater;
            getfield com.jcraft.jzlib.Inflater.next_in_index:I
            iload 5 /* oldNextInIndex */
            isub
            invokevirtual io.netty.buffer.ByteBuf.skipBytes:(I)Lio/netty/buffer/ByteBuf;
            pop
        50: .line 158
            aload 6 /* decompressed */
            invokevirtual io.netty.buffer.ByteBuf.isReadable:()Z
            ifeq 53
        51: .line 159
            aload 3 /* out */
            aload 6 /* decompressed */
            invokeinterface java.util.List.add:(Ljava/lang/Object;)Z
            pop
        52: .line 160
            goto 59
        53: .line 161
      StackMap locals:
      StackMap stack:
            aload 6 /* decompressed */
            invokevirtual io.netty.buffer.ByteBuf.release:()Z
            pop
        end local 6 // io.netty.buffer.ByteBuf decompressed
        end local 5 // int oldNextInIndex
        54: .line 164
            goto 59
      StackMap locals: io.netty.handler.codec.compression.JZlibDecoder io.netty.channel.ChannelHandlerContext io.netty.buffer.ByteBuf java.util.List int
      StackMap stack: java.lang.Throwable
        55: astore 11
        56: .line 169
            aload 0 /* this */
            getfield io.netty.handler.codec.compression.JZlibDecoder.z:Lcom/jcraft/jzlib/Inflater;
            aconst_null
            putfield com.jcraft.jzlib.Inflater.next_in:[B
        57: .line 170
            aload 0 /* this */
            getfield io.netty.handler.codec.compression.JZlibDecoder.z:Lcom/jcraft/jzlib/Inflater;
            aconst_null
            putfield com.jcraft.jzlib.Inflater.next_out:[B
        58: .line 171
            aload 11
            athrow
        59: .line 169
      StackMap locals:
      StackMap stack:
            aload 0 /* this */
            getfield io.netty.handler.codec.compression.JZlibDecoder.z:Lcom/jcraft/jzlib/Inflater;
            aconst_null
            putfield com.jcraft.jzlib.Inflater.next_in:[B
        60: .line 170
            aload 0 /* this */
            getfield io.netty.handler.codec.compression.JZlibDecoder.z:Lcom/jcraft/jzlib/Inflater;
            aconst_null
            putfield com.jcraft.jzlib.Inflater.next_out:[B
        61: .line 172
            return
        end local 4 // int inputLength
        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.compression.JZlibDecoder this
      LocalVariableTable:
        Start  End  Slot             Name  Signature
            0   62     0             this  Lio/netty/handler/codec/compression/JZlibDecoder;
            0   62     1              ctx  Lio/netty/channel/ChannelHandlerContext;
            0   62     2               in  Lio/netty/buffer/ByteBuf;
            0   62     3              out  Ljava/util/List<Ljava/lang/Object;>;
            4   62     4      inputLength  I
           12   15     5            array  [B
           16   54     5   oldNextInIndex  I
           17   54     6     decompressed  Lio/netty/buffer/ByteBuf;
           22   41     7  oldNextOutIndex  I
           23   41     8       resultCode  I
           24   41     9     outputLength  I
      Exception table:
        from    to  target  type
          17    42      42  any
           6    55      55  any
    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   
}
SourceFile: "JZlibDecoder.java"
InnerClasses:
  public final WrapperType = com.jcraft.jzlib.JZlib$WrapperType of com.jcraft.jzlib.JZlib