https://commons.apache.org/proper/commons-compress/: Apache Commons Compress software defines an API for working with compression and archive formats. These include: bzip2, gzip, pack200, lzma, xz, Snappy, traditional Unix Compress, DEFLATE, DEFLATE64, LZ4, Brotli, Zstandard and ar, cpio, jar, tar, zip, dump, 7z, arj. (The Apache Software Foundation)
  • Wolfgang Glas
  • Christian Kohlschütte
  • Bear Giles
  • Michael Kuss
  • Lasse Collin
  • John Kodis
  • BELUGA BEHR
  • Simon Spero
  • Michael Hausegger
  • Torsten Curdt
  • Stefan Bodewig
  • Sebastian Bazley
  • Christian Grobmeier
  • Julius Davies
  • Damjan Jovanovic
  • Emmanuel Bourg
  • Gary Gregory
  • Rob Tompkins 
public class org.apache.commons.compress.compressors.zstandard.ZstdUtils
  minor version: 0
  major version: 59
  flags: flags: (0x0021) ACC_PUBLIC, ACC_SUPER
  this_class: org.apache.commons.compress.compressors.zstandard.ZstdUtils
  super_class: java.lang.Object
{
  private static final byte[] ZSTANDARD_FRAME_MAGIC;
    descriptor: [B
    flags: (0x001a) ACC_PRIVATE, ACC_STATIC, ACC_FINAL

  private static final byte[] SKIPPABLE_FRAME_MAGIC;
    descriptor: [B
    flags: (0x001a) ACC_PRIVATE, ACC_STATIC, ACC_FINAL

  private static volatile org.apache.commons.compress.compressors.zstandard.ZstdUtils$CachedAvailability cachedZstdAvailability;
    descriptor: Lorg/apache/commons/compress/compressors/zstandard/ZstdUtils$CachedAvailability;
    flags: (0x004a) ACC_PRIVATE, ACC_STATIC, ACC_VOLATILE

  static void <clinit>();
    descriptor: ()V
    flags: (0x0008) ACC_STATIC
    Code:
      stack=4, locals=0, args_size=0
         0: .line 35
            iconst_4
            newarray 8
            dup
            iconst_0
         1: .line 36
            bipush 40
            bastore
            dup
            iconst_1
            bipush -75
            bastore
            dup
            iconst_2
            bipush 47
            bastore
            dup
            iconst_3
            bipush -3
            bastore
         2: .line 35
            putstatic org.apache.commons.compress.compressors.zstandard.ZstdUtils.ZSTANDARD_FRAME_MAGIC:[B
         3: .line 42
            iconst_3
            newarray 8
            dup
            iconst_0
         4: .line 43
            bipush 42
            bastore
            dup
            iconst_1
            bipush 77
            bastore
            dup
            iconst_2
            bipush 24
            bastore
         5: .line 42
            putstatic org.apache.commons.compress.compressors.zstandard.ZstdUtils.SKIPPABLE_FRAME_MAGIC:[B
         6: .line 49
            getstatic org.apache.commons.compress.compressors.zstandard.ZstdUtils$CachedAvailability.DONT_CACHE:Lorg/apache/commons/compress/compressors/zstandard/ZstdUtils$CachedAvailability;
            putstatic org.apache.commons.compress.compressors.zstandard.ZstdUtils.cachedZstdAvailability:Lorg/apache/commons/compress/compressors/zstandard/ZstdUtils$CachedAvailability;
         7: .line 51
            ldc "org.osgi.framework.BundleEvent"
            invokestatic java.lang.Class.forName:(Ljava/lang/String;)Ljava/lang/Class;
            pop
         8: .line 52
            goto 11
      StackMap locals:
      StackMap stack: java.lang.Exception
         9: pop
        10: .line 53
            iconst_1
            invokestatic org.apache.commons.compress.compressors.zstandard.ZstdUtils.setCacheZstdAvailablity:(Z)V
        11: .line 55
      StackMap locals:
      StackMap stack:
            return
      LocalVariableTable:
        Start  End  Slot  Name  Signature
      Exception table:
        from    to  target  type
           7     8       9  Class java.lang.Exception

  private void <init>();
    descriptor: ()V
    flags: (0x0002) ACC_PRIVATE
    Code:
      stack=1, locals=1, args_size=1
        start local 0 // org.apache.commons.compress.compressors.zstandard.ZstdUtils this
         0: .line 58
            aload 0 /* this */
            invokespecial java.lang.Object.<init>:()V
         1: .line 59
            return
        end local 0 // org.apache.commons.compress.compressors.zstandard.ZstdUtils this
      LocalVariableTable:
        Start  End  Slot  Name  Signature
            0    2     0  this  Lorg/apache/commons/compress/compressors/zstandard/ZstdUtils;

  public static boolean isZstdCompressionAvailable();
    descriptor: ()Z
    flags: (0x0009) ACC_PUBLIC, ACC_STATIC
    Code:
      stack=2, locals=1, args_size=0
         0: .line 66
            getstatic org.apache.commons.compress.compressors.zstandard.ZstdUtils.cachedZstdAvailability:Lorg/apache/commons/compress/compressors/zstandard/ZstdUtils$CachedAvailability;
            astore 0 /* cachedResult */
        start local 0 // org.apache.commons.compress.compressors.zstandard.ZstdUtils$CachedAvailability cachedResult
         1: .line 67
            aload 0 /* cachedResult */
            getstatic org.apache.commons.compress.compressors.zstandard.ZstdUtils$CachedAvailability.DONT_CACHE:Lorg/apache/commons/compress/compressors/zstandard/ZstdUtils$CachedAvailability;
            if_acmpeq 4
         2: .line 68
            aload 0 /* cachedResult */
            getstatic org.apache.commons.compress.compressors.zstandard.ZstdUtils$CachedAvailability.CACHED_AVAILABLE:Lorg/apache/commons/compress/compressors/zstandard/ZstdUtils$CachedAvailability;
            if_acmpne 3
            iconst_1
            ireturn
      StackMap locals: org.apache.commons.compress.compressors.zstandard.ZstdUtils$CachedAvailability
      StackMap stack:
         3: iconst_0
            ireturn
         4: .line 70
      StackMap locals:
      StackMap stack:
            invokestatic org.apache.commons.compress.compressors.zstandard.ZstdUtils.internalIsZstdCompressionAvailable:()Z
            ireturn
        end local 0 // org.apache.commons.compress.compressors.zstandard.ZstdUtils$CachedAvailability cachedResult
      LocalVariableTable:
        Start  End  Slot          Name  Signature
            1    5     0  cachedResult  Lorg/apache/commons/compress/compressors/zstandard/ZstdUtils$CachedAvailability;

  private static boolean internalIsZstdCompressionAvailable();
    descriptor: ()Z
    flags: (0x000a) ACC_PRIVATE, ACC_STATIC
    Code:
      stack=1, locals=0, args_size=0
         0: .line 75
            ldc "com.github.luben.zstd.ZstdInputStream"
            invokestatic java.lang.Class.forName:(Ljava/lang/String;)Ljava/lang/Class;
            pop
         1: .line 76
            iconst_1
            ireturn
         2: .line 77
      StackMap locals:
      StackMap stack: java.lang.Throwable
            pop
         3: .line 78
            iconst_0
            ireturn
      LocalVariableTable:
        Start  End  Slot  Name  Signature
      Exception table:
        from    to  target  type
           0     1       2  Class java.lang.NoClassDefFoundError
           0     1       2  Class java.lang.Exception

  public static void setCacheZstdAvailablity(boolean);
    descriptor: (Z)V
    flags: (0x0009) ACC_PUBLIC, ACC_STATIC
    Code:
      stack=2, locals=2, args_size=1
        start local 0 // boolean doCache
         0: .line 89
            iload 0 /* doCache */
            ifne 3
         1: .line 90
            getstatic org.apache.commons.compress.compressors.zstandard.ZstdUtils$CachedAvailability.DONT_CACHE:Lorg/apache/commons/compress/compressors/zstandard/ZstdUtils$CachedAvailability;
            putstatic org.apache.commons.compress.compressors.zstandard.ZstdUtils.cachedZstdAvailability:Lorg/apache/commons/compress/compressors/zstandard/ZstdUtils$CachedAvailability;
         2: .line 91
            goto 8
      StackMap locals:
      StackMap stack:
         3: getstatic org.apache.commons.compress.compressors.zstandard.ZstdUtils.cachedZstdAvailability:Lorg/apache/commons/compress/compressors/zstandard/ZstdUtils$CachedAvailability;
            getstatic org.apache.commons.compress.compressors.zstandard.ZstdUtils$CachedAvailability.DONT_CACHE:Lorg/apache/commons/compress/compressors/zstandard/ZstdUtils$CachedAvailability;
            if_acmpne 8
         4: .line 92
            invokestatic org.apache.commons.compress.compressors.zstandard.ZstdUtils.internalIsZstdCompressionAvailable:()Z
            istore 1 /* hasZstd */
        start local 1 // boolean hasZstd
         5: .line 93
            iload 1 /* hasZstd */
            ifeq 6
            getstatic org.apache.commons.compress.compressors.zstandard.ZstdUtils$CachedAvailability.CACHED_AVAILABLE:Lorg/apache/commons/compress/compressors/zstandard/ZstdUtils$CachedAvailability;
            goto 7
         6: .line 94
      StackMap locals: int
      StackMap stack:
            getstatic org.apache.commons.compress.compressors.zstandard.ZstdUtils$CachedAvailability.CACHED_UNAVAILABLE:Lorg/apache/commons/compress/compressors/zstandard/ZstdUtils$CachedAvailability;
         7: .line 93
      StackMap locals:
      StackMap stack: org.apache.commons.compress.compressors.zstandard.ZstdUtils$CachedAvailability
            putstatic org.apache.commons.compress.compressors.zstandard.ZstdUtils.cachedZstdAvailability:Lorg/apache/commons/compress/compressors/zstandard/ZstdUtils$CachedAvailability;
        end local 1 // boolean hasZstd
         8: .line 96
      StackMap locals:
      StackMap stack:
            return
        end local 0 // boolean doCache
      LocalVariableTable:
        Start  End  Slot     Name  Signature
            0    9     0  doCache  Z
            5    8     1  hasZstd  Z
    MethodParameters:
         Name  Flags
      doCache  final

  public static boolean matches(byte[], int);
    descriptor: ([BI)Z
    flags: (0x0009) ACC_PUBLIC, ACC_STATIC
    Code:
      stack=3, locals=4, args_size=2
        start local 0 // byte[] signature
        start local 1 // int length
         0: .line 107
            iload 1 /* length */
            getstatic org.apache.commons.compress.compressors.zstandard.ZstdUtils.ZSTANDARD_FRAME_MAGIC:[B
            arraylength
            if_icmpge 2
         1: .line 108
            iconst_0
            ireturn
         2: .line 111
      StackMap locals:
      StackMap stack:
            iconst_1
            istore 2 /* isZstandard */
        start local 2 // boolean isZstandard
         3: .line 112
            iconst_0
            istore 3 /* i */
        start local 3 // int i
         4: goto 9
         5: .line 113
      StackMap locals: int int
      StackMap stack:
            aload 0 /* signature */
            iload 3 /* i */
            baload
            getstatic org.apache.commons.compress.compressors.zstandard.ZstdUtils.ZSTANDARD_FRAME_MAGIC:[B
            iload 3 /* i */
            baload
            if_icmpeq 8
         6: .line 114
            iconst_0
            istore 2 /* isZstandard */
         7: .line 115
            goto 10
         8: .line 112
      StackMap locals:
      StackMap stack:
            iinc 3 /* i */ 1
      StackMap locals:
      StackMap stack:
         9: iload 3 /* i */
            getstatic org.apache.commons.compress.compressors.zstandard.ZstdUtils.ZSTANDARD_FRAME_MAGIC:[B
            arraylength
            if_icmplt 5
        end local 3 // int i
        10: .line 118
      StackMap locals:
      StackMap stack:
            iload 2 /* isZstandard */
            ifeq 12
        11: .line 119
            iconst_1
            ireturn
        12: .line 122
      StackMap locals:
      StackMap stack:
            bipush 80
            aload 0 /* signature */
            iconst_0
            baload
            sipush 240
            iand
            if_icmpne 20
        13: .line 124
            iconst_0
            istore 3 /* i */
        start local 3 // int i
        14: goto 18
        15: .line 125
      StackMap locals: int
      StackMap stack:
            aload 0 /* signature */
            iload 3 /* i */
            iconst_1
            iadd
            baload
            getstatic org.apache.commons.compress.compressors.zstandard.ZstdUtils.SKIPPABLE_FRAME_MAGIC:[B
            iload 3 /* i */
            baload
            if_icmpeq 17
        16: .line 126
            iconst_0
            ireturn
        17: .line 124
      StackMap locals:
      StackMap stack:
            iinc 3 /* i */ 1
      StackMap locals:
      StackMap stack:
        18: iload 3 /* i */
            getstatic org.apache.commons.compress.compressors.zstandard.ZstdUtils.SKIPPABLE_FRAME_MAGIC:[B
            arraylength
            if_icmplt 15
        end local 3 // int i
        19: .line 130
            iconst_1
            ireturn
        20: .line 133
      StackMap locals:
      StackMap stack:
            iconst_0
            ireturn
        end local 2 // boolean isZstandard
        end local 1 // int length
        end local 0 // byte[] signature
      LocalVariableTable:
        Start  End  Slot         Name  Signature
            0   21     0    signature  [B
            0   21     1       length  I
            3   21     2  isZstandard  Z
            4   10     3            i  I
           14   19     3            i  I
    MethodParameters:
           Name  Flags
      signature  final
      length     final

  static org.apache.commons.compress.compressors.zstandard.ZstdUtils$CachedAvailability getCachedZstdAvailability();
    descriptor: ()Lorg/apache/commons/compress/compressors/zstandard/ZstdUtils$CachedAvailability;
    flags: (0x0008) ACC_STATIC
    Code:
      stack=1, locals=0, args_size=0
         0: .line 138
            getstatic org.apache.commons.compress.compressors.zstandard.ZstdUtils.cachedZstdAvailability:Lorg/apache/commons/compress/compressors/zstandard/ZstdUtils$CachedAvailability;
            areturn
      LocalVariableTable:
        Start  End  Slot  Name  Signature
}
SourceFile: "ZstdUtils.java"
NestMembers:
  org.apache.commons.compress.compressors.zstandard.ZstdUtils$CachedAvailability
InnerClasses:
  final CachedAvailability = org.apache.commons.compress.compressors.zstandard.ZstdUtils$CachedAvailability of org.apache.commons.compress.compressors.zstandard.ZstdUtils