http://www.bouncycastle.org/java.html: The Bouncy Castle Crypto package is a Java implementation of cryptographic algorithms. This jar contains JCE provider and lightweight API for the Bouncy Castle Cryptography APIs for JDK 1.5. 
public abstract class org.bouncycastle.crypto.digests.GeneralDigest implements org.bouncycastle.crypto.ExtendedDigest
  minor version: 0
  major version: 59
  flags: flags: (0x0421) ACC_PUBLIC, ACC_SUPER, ACC_ABSTRACT
  this_class: org.bouncycastle.crypto.digests.GeneralDigest
  super_class: java.lang.Object
{
  private static final int BYTE_LENGTH;
    descriptor: I
    flags: (0x001a) ACC_PRIVATE, ACC_STATIC, ACC_FINAL
    ConstantValue: 64

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

  private int xBufOff;
    descriptor: I
    flags: (0x0002) ACC_PRIVATE

  private long byteCount;
    descriptor: J
    flags: (0x0002) ACC_PRIVATE

  protected void <init>();
    descriptor: ()V
    flags: (0x0004) ACC_PROTECTED
    Code:
      stack=2, locals=1, args_size=1
        start local 0 // org.bouncycastle.crypto.digests.GeneralDigest this
         0: .line 21
            aload 0 /* this */
            invokespecial java.lang.Object.<init>:()V
         1: .line 23
            aload 0 /* this */
            iconst_4
            newarray 8
            putfield org.bouncycastle.crypto.digests.GeneralDigest.xBuf:[B
         2: .line 24
            aload 0 /* this */
            iconst_0
            putfield org.bouncycastle.crypto.digests.GeneralDigest.xBufOff:I
         3: .line 25
            return
        end local 0 // org.bouncycastle.crypto.digests.GeneralDigest this
      LocalVariableTable:
        Start  End  Slot  Name  Signature
            0    4     0  this  Lorg/bouncycastle/crypto/digests/GeneralDigest;

  protected void <init>(org.bouncycastle.crypto.digests.GeneralDigest);
    descriptor: (Lorg/bouncycastle/crypto/digests/GeneralDigest;)V
    flags: (0x0004) ACC_PROTECTED
    Code:
      stack=5, locals=2, args_size=2
        start local 0 // org.bouncycastle.crypto.digests.GeneralDigest this
        start local 1 // org.bouncycastle.crypto.digests.GeneralDigest t
         0: .line 32
            aload 0 /* this */
            invokespecial java.lang.Object.<init>:()V
         1: .line 34
            aload 0 /* this */
            aload 1 /* t */
            getfield org.bouncycastle.crypto.digests.GeneralDigest.xBuf:[B
            arraylength
            newarray 8
            putfield org.bouncycastle.crypto.digests.GeneralDigest.xBuf:[B
         2: .line 35
            aload 1 /* t */
            getfield org.bouncycastle.crypto.digests.GeneralDigest.xBuf:[B
            iconst_0
            aload 0 /* this */
            getfield org.bouncycastle.crypto.digests.GeneralDigest.xBuf:[B
            iconst_0
            aload 1 /* t */
            getfield org.bouncycastle.crypto.digests.GeneralDigest.xBuf:[B
            arraylength
            invokestatic java.lang.System.arraycopy:(Ljava/lang/Object;ILjava/lang/Object;II)V
         3: .line 37
            aload 0 /* this */
            aload 1 /* t */
            getfield org.bouncycastle.crypto.digests.GeneralDigest.xBufOff:I
            putfield org.bouncycastle.crypto.digests.GeneralDigest.xBufOff:I
         4: .line 38
            aload 0 /* this */
            aload 1 /* t */
            getfield org.bouncycastle.crypto.digests.GeneralDigest.byteCount:J
            putfield org.bouncycastle.crypto.digests.GeneralDigest.byteCount:J
         5: .line 39
            return
        end local 1 // org.bouncycastle.crypto.digests.GeneralDigest t
        end local 0 // org.bouncycastle.crypto.digests.GeneralDigest this
      LocalVariableTable:
        Start  End  Slot  Name  Signature
            0    6     0  this  Lorg/bouncycastle/crypto/digests/GeneralDigest;
            0    6     1     t  Lorg/bouncycastle/crypto/digests/GeneralDigest;
    MethodParameters:
      Name  Flags
      t     

  public void update(byte);
    descriptor: (B)V
    flags: (0x0001) ACC_PUBLIC
    Code:
      stack=5, locals=2, args_size=2
        start local 0 // org.bouncycastle.crypto.digests.GeneralDigest this
        start local 1 // byte in
         0: .line 44
            aload 0 /* this */
            getfield org.bouncycastle.crypto.digests.GeneralDigest.xBuf:[B
            aload 0 /* this */
            dup
            getfield org.bouncycastle.crypto.digests.GeneralDigest.xBufOff:I
            dup_x1
            iconst_1
            iadd
            putfield org.bouncycastle.crypto.digests.GeneralDigest.xBufOff:I
            iload 1 /* in */
            bastore
         1: .line 46
            aload 0 /* this */
            getfield org.bouncycastle.crypto.digests.GeneralDigest.xBufOff:I
            aload 0 /* this */
            getfield org.bouncycastle.crypto.digests.GeneralDigest.xBuf:[B
            arraylength
            if_icmpne 4
         2: .line 48
            aload 0 /* this */
            aload 0 /* this */
            getfield org.bouncycastle.crypto.digests.GeneralDigest.xBuf:[B
            iconst_0
            invokevirtual org.bouncycastle.crypto.digests.GeneralDigest.processWord:([BI)V
         3: .line 49
            aload 0 /* this */
            iconst_0
            putfield org.bouncycastle.crypto.digests.GeneralDigest.xBufOff:I
         4: .line 52
      StackMap locals:
      StackMap stack:
            aload 0 /* this */
            dup
            getfield org.bouncycastle.crypto.digests.GeneralDigest.byteCount:J
            lconst_1
            ladd
            putfield org.bouncycastle.crypto.digests.GeneralDigest.byteCount:J
         5: .line 53
            return
        end local 1 // byte in
        end local 0 // org.bouncycastle.crypto.digests.GeneralDigest this
      LocalVariableTable:
        Start  End  Slot  Name  Signature
            0    6     0  this  Lorg/bouncycastle/crypto/digests/GeneralDigest;
            0    6     1    in  B
    MethodParameters:
      Name  Flags
      in    

  public void update(byte[], int, int);
    descriptor: ([BII)V
    flags: (0x0001) ACC_PUBLIC
    Code:
      stack=5, locals=4, args_size=4
        start local 0 // org.bouncycastle.crypto.digests.GeneralDigest this
        start local 1 // byte[] in
        start local 2 // int inOff
        start local 3 // int len
         0: .line 63
            goto 4
         1: .line 65
      StackMap locals:
      StackMap stack:
            aload 0 /* this */
            aload 1 /* in */
            iload 2 /* inOff */
            baload
            invokevirtual org.bouncycastle.crypto.digests.GeneralDigest.update:(B)V
         2: .line 67
            iinc 2 /* inOff */ 1
         3: .line 68
            iinc 3 /* len */ -1
         4: .line 63
      StackMap locals:
      StackMap stack:
            aload 0 /* this */
            getfield org.bouncycastle.crypto.digests.GeneralDigest.xBufOff:I
            ifeq 10
            iload 3 /* len */
            ifgt 1
         5: .line 74
            goto 10
         6: .line 76
      StackMap locals:
      StackMap stack:
            aload 0 /* this */
            aload 1 /* in */
            iload 2 /* inOff */
            invokevirtual org.bouncycastle.crypto.digests.GeneralDigest.processWord:([BI)V
         7: .line 78
            iload 2 /* inOff */
            aload 0 /* this */
            getfield org.bouncycastle.crypto.digests.GeneralDigest.xBuf:[B
            arraylength
            iadd
            istore 2 /* inOff */
         8: .line 79
            iload 3 /* len */
            aload 0 /* this */
            getfield org.bouncycastle.crypto.digests.GeneralDigest.xBuf:[B
            arraylength
            isub
            istore 3 /* len */
         9: .line 80
            aload 0 /* this */
            dup
            getfield org.bouncycastle.crypto.digests.GeneralDigest.byteCount:J
            aload 0 /* this */
            getfield org.bouncycastle.crypto.digests.GeneralDigest.xBuf:[B
            arraylength
            i2l
            ladd
            putfield org.bouncycastle.crypto.digests.GeneralDigest.byteCount:J
        10: .line 74
      StackMap locals:
      StackMap stack:
            iload 3 /* len */
            aload 0 /* this */
            getfield org.bouncycastle.crypto.digests.GeneralDigest.xBuf:[B
            arraylength
            if_icmpgt 6
        11: .line 86
            goto 15
        12: .line 88
      StackMap locals:
      StackMap stack:
            aload 0 /* this */
            aload 1 /* in */
            iload 2 /* inOff */
            baload
            invokevirtual org.bouncycastle.crypto.digests.GeneralDigest.update:(B)V
        13: .line 90
            iinc 2 /* inOff */ 1
        14: .line 91
            iinc 3 /* len */ -1
        15: .line 86
      StackMap locals:
      StackMap stack:
            iload 3 /* len */
            ifgt 12
        16: .line 93
            return
        end local 3 // int len
        end local 2 // int inOff
        end local 1 // byte[] in
        end local 0 // org.bouncycastle.crypto.digests.GeneralDigest this
      LocalVariableTable:
        Start  End  Slot   Name  Signature
            0   17     0   this  Lorg/bouncycastle/crypto/digests/GeneralDigest;
            0   17     1     in  [B
            0   17     2  inOff  I
            0   17     3    len  I
    MethodParameters:
       Name  Flags
      in     
      inOff  
      len    

  public void finish();
    descriptor: ()V
    flags: (0x0001) ACC_PUBLIC
    Code:
      stack=3, locals=3, args_size=1
        start local 0 // org.bouncycastle.crypto.digests.GeneralDigest this
         0: .line 97
            aload 0 /* this */
            getfield org.bouncycastle.crypto.digests.GeneralDigest.byteCount:J
            iconst_3
            lshl
            lstore 1 /* bitLength */
        start local 1 // long bitLength
         1: .line 102
            aload 0 /* this */
            bipush -128
            invokevirtual org.bouncycastle.crypto.digests.GeneralDigest.update:(B)V
         2: .line 104
            goto 4
         3: .line 106
      StackMap locals: long
      StackMap stack:
            aload 0 /* this */
            iconst_0
            invokevirtual org.bouncycastle.crypto.digests.GeneralDigest.update:(B)V
         4: .line 104
      StackMap locals:
      StackMap stack:
            aload 0 /* this */
            getfield org.bouncycastle.crypto.digests.GeneralDigest.xBufOff:I
            ifne 3
         5: .line 109
            aload 0 /* this */
            lload 1 /* bitLength */
            invokevirtual org.bouncycastle.crypto.digests.GeneralDigest.processLength:(J)V
         6: .line 111
            aload 0 /* this */
            invokevirtual org.bouncycastle.crypto.digests.GeneralDigest.processBlock:()V
         7: .line 112
            return
        end local 1 // long bitLength
        end local 0 // org.bouncycastle.crypto.digests.GeneralDigest this
      LocalVariableTable:
        Start  End  Slot       Name  Signature
            0    8     0       this  Lorg/bouncycastle/crypto/digests/GeneralDigest;
            1    8     1  bitLength  J

  public void reset();
    descriptor: ()V
    flags: (0x0001) ACC_PUBLIC
    Code:
      stack=3, locals=2, args_size=1
        start local 0 // org.bouncycastle.crypto.digests.GeneralDigest this
         0: .line 116
            aload 0 /* this */
            lconst_0
            putfield org.bouncycastle.crypto.digests.GeneralDigest.byteCount:J
         1: .line 118
            aload 0 /* this */
            iconst_0
            putfield org.bouncycastle.crypto.digests.GeneralDigest.xBufOff:I
         2: .line 119
            iconst_0
            istore 1 /* i */
        start local 1 // int i
         3: goto 6
         4: .line 121
      StackMap locals: int
      StackMap stack:
            aload 0 /* this */
            getfield org.bouncycastle.crypto.digests.GeneralDigest.xBuf:[B
            iload 1 /* i */
            iconst_0
            bastore
         5: .line 119
            iinc 1 /* i */ 1
      StackMap locals:
      StackMap stack:
         6: iload 1 /* i */
            aload 0 /* this */
            getfield org.bouncycastle.crypto.digests.GeneralDigest.xBuf:[B
            arraylength
            if_icmplt 4
        end local 1 // int i
         7: .line 123
            return
        end local 0 // org.bouncycastle.crypto.digests.GeneralDigest this
      LocalVariableTable:
        Start  End  Slot  Name  Signature
            0    8     0  this  Lorg/bouncycastle/crypto/digests/GeneralDigest;
            3    7     1     i  I

  public int getByteLength();
    descriptor: ()I
    flags: (0x0001) ACC_PUBLIC
    Code:
      stack=1, locals=1, args_size=1
        start local 0 // org.bouncycastle.crypto.digests.GeneralDigest this
         0: .line 127
            bipush 64
            ireturn
        end local 0 // org.bouncycastle.crypto.digests.GeneralDigest this
      LocalVariableTable:
        Start  End  Slot  Name  Signature
            0    1     0  this  Lorg/bouncycastle/crypto/digests/GeneralDigest;

  protected abstract void processWord(byte[], int);
    descriptor: ([BI)V
    flags: (0x0404) ACC_PROTECTED, ACC_ABSTRACT
    MethodParameters:
       Name  Flags
      in     
      inOff  

  protected abstract void processLength(long);
    descriptor: (J)V
    flags: (0x0404) ACC_PROTECTED, ACC_ABSTRACT
    MethodParameters:
           Name  Flags
      bitLength  

  protected abstract void processBlock();
    descriptor: ()V
    flags: (0x0404) ACC_PROTECTED, ACC_ABSTRACT
}
SourceFile: "GeneralDigest.java"