1 files changed, 111 insertions, 0 deletions
diff --git a/libraries/spongycastle/core/src/main/java/org/spongycastle/asn1/IndefiniteLengthInputStream.java b/libraries/spongycastle/core/src/main/java/org/spongycastle/asn1/IndefiniteLengthInputStream.java
new file mode 100644
index 000000000..39e003a41
--- /dev/null
+++ b/libraries/spongycastle/core/src/main/java/org/spongycastle/asn1/IndefiniteLengthInputStream.java
@@ -0,0 +1,111 @@
+package org.spongycastle.asn1;
+
+import java.io.EOFException;
+import java.io.IOException;
+import java.io.InputStream;
+
+class IndefiniteLengthInputStream
+    extends LimitedInputStream
+{
+    private int _b1;
+    private int _b2;
+    private boolean _eofReached = false;
+    private boolean _eofOn00 = true;
+
+    IndefiniteLengthInputStream(
+        InputStream in,
+        int         limit)
+        throws IOException
+    {
+        super(in, limit);
+
+        _b1 = in.read();
+        _b2 = in.read();
+
+        if (_b2 < 0)
+        {
+            // Corrupted stream
+            throw new EOFException();
+        }
+
+        checkForEof();
+    }
+
+    void setEofOn00(
+        boolean eofOn00)
+    {
+        _eofOn00 = eofOn00;
+        checkForEof();
+    }
+
+    private boolean checkForEof()
+    {
+        if (!_eofReached && _eofOn00 && (_b1 == 0x00 && _b2 == 0x00))
+        {
+            _eofReached = true;
+            setParentEofDetect(true);
+        }
+        return _eofReached;
+    }
+
+    public int read(byte[] b, int off, int len)
+        throws IOException
+    {
+        // Only use this optimisation if we aren't checking for 00
+        if (_eofOn00 || len < 3)
+        {
+            return super.read(b, off, len);
+        }
+
+        if (_eofReached)
+        {
+            return -1;
+        }
+
+        int numRead = _in.read(b, off + 2, len - 2);
+
+        if (numRead < 0)
+        {
+            // Corrupted stream
+            throw new EOFException();
+        }
+
+        b[off] = (byte)_b1;
+        b[off + 1] = (byte)_b2;
+
+        _b1 = _in.read();
+        _b2 = _in.read();
+
+        if (_b2 < 0)
+        {
+            // Corrupted stream
+            throw new EOFException();
+        }
+
+        return numRead + 2;
+    }
+
+    public int read()
+        throws IOException
+    {
+        if (checkForEof())
+        {
+            return -1;
+        }
+
+        int b = _in.read();
+
+        if (b < 0)
+        {
+            // Corrupted stream
+            throw new EOFException();
+        }
+
+        int v = _b1;
+
+        _b1 = _b2;
+        _b2 = b;
+
+        return v;
+    }
+}