1 files changed, 105 insertions, 0 deletions
diff --git a/libraries/spongycastle/core/src/main/java/org/spongycastle/asn1/DefiniteLengthInputStream.java b/libraries/spongycastle/core/src/main/java/org/spongycastle/asn1/DefiniteLengthInputStream.java
new file mode 100644
index 000000000..711f173df
--- /dev/null
+++ b/libraries/spongycastle/core/src/main/java/org/spongycastle/asn1/DefiniteLengthInputStream.java
@@ -0,0 +1,105 @@
+package org.spongycastle.asn1;
+
+import java.io.EOFException;
+import java.io.IOException;
+import java.io.InputStream;
+
+import org.spongycastle.util.io.Streams;
+
+class DefiniteLengthInputStream
+        extends LimitedInputStream
+{
+    private static final byte[] EMPTY_BYTES = new byte[0];
+
+    private final int _originalLength;
+    private int _remaining;
+
+    DefiniteLengthInputStream(
+        InputStream in,
+        int         length)
+    {
+        super(in, length);
+
+        if (length < 0)
+        {
+            throw new IllegalArgumentException("negative lengths not allowed");
+        }
+
+        this._originalLength = length;
+        this._remaining = length;
+
+        if (length == 0)
+        {
+            setParentEofDetect(true);
+        }
+    }
+
+    int getRemaining()
+    {
+        return _remaining;
+    }
+
+    public int read()
+        throws IOException
+    {
+        if (_remaining == 0)
+        {
+            return -1;
+        }
+
+        int b = _in.read();
+
+        if (b < 0)
+        {
+            throw new EOFException("DEF length " + _originalLength + " object truncated by " + _remaining);
+        }
+
+        if (--_remaining == 0)
+        {
+            setParentEofDetect(true);
+        }
+
+        return b;
+    }
+
+    public int read(byte[] buf, int off, int len)
+        throws IOException
+    {
+        if (_remaining == 0)
+        {
+            return -1;
+        }
+
+        int toRead = Math.min(len, _remaining);
+        int numRead = _in.read(buf, off, toRead);
+
+        if (numRead < 0)
+        {
+            throw new EOFException("DEF length " + _originalLength + " object truncated by " + _remaining);
+        }
+
+        if ((_remaining -= numRead) == 0)
+        {
+            setParentEofDetect(true);
+        }
+
+        return numRead;
+    }
+
+    byte[] toByteArray()
+        throws IOException
+    {
+        if (_remaining == 0)
+        {
+            return EMPTY_BYTES;
+        }
+
+        byte[] bytes = new byte[_remaining];
+        if ((_remaining -= Streams.readFully(_in, bytes)) != 0)
+        {
+            throw new EOFException("DEF length " + _originalLength + " object truncated by " + _remaining);
+        }
+        setParentEofDetect(true);
+        return bytes;
+    }
+}