From ecd16bf6652c30c8eacbb2dabbc4e6dfd12236c7 Mon Sep 17 00:00:00 2001
From: Tom Tromey <tromey@redhat.com>
Date: Wed, 22 Sep 2004 20:16:17 +0000
Subject: re PR java/14446 (GZIPInputStream: corrupted gzip file - crc
 mismatch)

	PR libgcj/14446:
	* java/util/zip/GZIPInputStream.java (read): Avoid sign extension
	when comparing CRCs.
	* java/util/zip/InflaterInputStream.java (onebytebuffer): New
	field.
	(read()): New overload.

From-SVN: r87882
---
 libjava/java/util/zip/GZIPInputStream.java     |  4 +++-
 libjava/java/util/zip/InflaterInputStream.java | 16 ++++++++++++++++
 2 files changed, 19 insertions(+), 1 deletion(-)

(limited to 'libjava/java/util')

diff --git a/libjava/java/util/zip/GZIPInputStream.java b/libjava/java/util/zip/GZIPInputStream.java
index 9eef73e..5640163 100644
--- a/libjava/java/util/zip/GZIPInputStream.java
+++ b/libjava/java/util/zip/GZIPInputStream.java
@@ -230,7 +230,9 @@ public class GZIPInputStream
 	    tmp[i] = (byte) eof_read();
 	  }
 
-	int header_crc = read4(tmp, 0);
+	// Be careful to avoid sign extension here; CRC32.getValue()
+	// returns a long.
+	long header_crc = read4(tmp, 0) & 0xffffffffL;
 	if (crc.getValue() != header_crc)
 	  throw new ZipException("corrupted gzip file - crc mismatch");
 	int isize = read4(tmp, 4);
diff --git a/libjava/java/util/zip/InflaterInputStream.java b/libjava/java/util/zip/InflaterInputStream.java
index 27c29ff..3676a2c 100644
--- a/libjava/java/util/zip/InflaterInputStream.java
+++ b/libjava/java/util/zip/InflaterInputStream.java
@@ -70,6 +70,9 @@ public class InflaterInputStream extends FilterInputStream
    */
   protected int len;
 
+  // We just use this if we are decoding one byte at a time with the
+  // read() call.
+  private byte[] onebytebuffer = new byte[1];
 
   /**
    * Create an InflaterInputStream with the default decompresseor
@@ -156,6 +159,19 @@ public class InflaterInputStream extends FilterInputStream
   }
 
   /**
+   * Reads one byte of decompressed data.
+   *
+   * The byte is in the lower 8 bits of the int.
+   */
+  public int read() throws IOException
+  { 
+    int nread = read(onebytebuffer, 0, 1);
+    if (nread > 0)
+      return onebytebuffer[0] & 0xff;
+    return -1;
+  }
+
+  /**
    * Decompresses data into the byte array
    *
    * @param b the array to read and decompress data into
-- 
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