1 files changed, 154 insertions, 0 deletions
diff --git a/libjava/java/util/zip/GZIPInputStream.java b/libjava/java/util/zip/GZIPInputStream.java
new file mode 100644
index 00000000000..109ee82b1d2
--- /dev/null
+++ b/libjava/java/util/zip/GZIPInputStream.java
@@ -0,0 +1,154 @@
+// GZIPInputStream.java - Input tiler for reading gzip file.
+
+/* 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;
+
+import java.io.InputStream;
+import java.io.IOException;
+
+/**
+ * @author Tom Tromey
+ * @date May 17, 1999
+ */
+
+/* Written using on-line Java Platform 1.2 API Specification
+ * and JCL book.
+ * Believed complete and correct.
+ */
+
+public class GZIPInputStream extends InflaterInputStream
+{
+  public static final int GZIP_MAGIC = 0x8b1f;
+
+  public void close () throws IOException
+  {
+    // Nothing to do here.
+    super.close();
+  }
+
+  public GZIPInputStream (InputStream istream) throws IOException
+  {
+    this (istream, 512);
+  }
+
+  private final int eof_read () throws IOException
+  {
+    int r = in.read();
+    if (r == -1)
+      throw new ZipException ("gzip header corrupted");
+    return r & 0xff;
+  }
+
+  public GZIPInputStream (InputStream istream, int readsize)
+    throws IOException
+  {
+    super (istream, new Inflater (true), readsize);
+
+    // NOTE: header reading code taken from zlib's gzio.c.
+
+    // Read the magic number.
+    int magic = eof_read () | (eof_read () << 8);
+    if (magic != GZIP_MAGIC)
+      throw new ZipException ("gzip header corrupted");
+
+    int method = eof_read ();
+    int flags = eof_read ();
+    // Test from zlib.
+    if (method != Z_DEFLATED || (flags & RESERVED) != 0)
+      throw new ZipException ("gzip header corrupted");
+
+    // Discard time, xflags, OS code.
+    for (int i = 0; i < 6; ++i)
+      eof_read ();
+
+    // Skip the extra field.
+    if ((flags & EXTRA_FIELD) != 0)
+      {
+	int len = eof_read () | (eof_read () << 8);
+	while (len-- != 0)
+	  eof_read ();
+      }
+
+    if ((flags & ORIG_NAME) != 0)
+      {
+	while (true)
+	  {
+	    int c = eof_read ();
+	    if (c == 0)
+	      break;
+	  }
+      }
+
+    if ((flags & COMMENT) != 0)
+      {
+	while (true)
+	  {
+	    int c = eof_read ();
+	    if (c == 0)
+	      break;
+	  }
+      }
+
+    if ((flags & HEAD_CRC) != 0)
+      {
+	// FIXME: consider checking CRC of the header.
+	eof_read ();
+	eof_read ();
+      }
+
+    crc = new CRC32 ();
+  }
+
+  public int read (byte[] buf, int off, int len) throws IOException
+  {
+    if (eos)
+      return -1;
+    int r = super.read(buf, off, len);
+    if (r == -1)
+      {
+	eos = true;
+	int header_crc = read4 ();
+	if (crc.getValue() != header_crc)
+	  throw new ZipException ("corrupted gzip file");
+	// Read final `ISIZE' field.
+	// FIXME: should we check this length?
+	read4 ();
+	return -1;
+      }
+    crc.update(buf, off, r);
+    return r;
+  }
+
+  private final int read4 () throws IOException
+  {
+    int byte0 = in.read();
+    int byte1 = in.read();
+    int byte2 = in.read();
+    int byte3 = in.read();
+    if (byte3 < 0)
+      throw new ZipException (".zip archive ended prematurely");
+    return ((byte3 & 0xFF) << 24) + ((byte2 & 0xFF) << 16)
+      + ((byte1 & 0xFF) << 8) + (byte0 & 0xFF);
+  }
+
+  // Checksum used by this input stream.
+  protected CRC32 crc;
+
+  // Indicates whether end-of-stream has been reached.
+  protected boolean eos;
+
+  // Some constants from zlib.
+  static final int Z_DEFLATED = 8;
+  static final int HEAD_CRC    = 0x02;
+  static final int EXTRA_FIELD = 0x04;
+  static final int ORIG_NAME   = 0x08;
+  static final int COMMENT     = 0x10;
+  static final int RESERVED    = 0xe0;
+}