Initial revision

From-SVN: r26263

1 files changed, 70 insertions, 0 deletions

diff --git a/libjava/java/util/zip/CRC32.java b/libjava/java/util/zip/CRC32.java
new file mode 100644
index 00000000000..ab19b58b1e9
--- /dev/null
+++ b/libjava/java/util/zip/CRC32.java
@@ -0,0 +1,70 @@
+/* Copyright (C) 1999  Cygnus Solutions
+
+   This file is part of libgcj.
+
+This software is copyrighted work licensed under the terms of the
+Libgcj License.  Please consult the file "LIBGCJ_LICENSE" for
+details.  */
+
+package java.util.zip;
+
+/**
+ * @author Per Bothner
+ * @date April 1, 1999.
+ */
+
+/*
+ * Written using on-line Java Platform 1.2 API Specification, as well
+ * as "The Java Class Libraries", 2nd edition (Addison-Wesley, 1998).
+ * The actual CRC32 algorithm is taken from RFC 1952.
+ * Status:  Believed complete and correct.
+ */
+
+public class CRC32 implements Checksum
+{
+  int crc = 0;
+
+  static int[] crc_table = make_crc_table();
+
+  /* Make the table for a fast CRC. */
+  static int[] make_crc_table ()
+  {
+    int[] crc_table = new int[256];
+    for (int n = 0; n < 256; n++)
+      {
+	int c = n;
+	for (int k = 8;  --k >= 0; )
+	  {
+	    if ((c & 1) != 0)
+	      c = 0xedb88320 ^ (c >>> 1);
+	    else
+	      c = c >>> 1;
+	  }
+	crc_table[n] = c;
+      }
+    return crc_table;
+  }
+
+  public long getValue ()
+  {
+    return (long) crc & 0xffffffffL;
+  }
+
+  public void reset () { crc = 0; }
+
+  public void update (int bval)
+  {
+    int c = ~crc;
+    c = crc_table[(c ^ bval) & 0xff] ^ (c >>> 8);
+    crc = ~c;
+  }
+
+  public void update (byte[] buf, int off, int len)
+  {
+    int c = ~crc;
+    while (--len >= 0)
+      c = crc_table[(c ^ buf[off++]) & 0xff] ^ (c >>> 8);
+    crc = ~c;
+  }
+  public void update (byte[] buf) { update(buf, 0, buf.length); }
+}