diff options
Diffstat (limited to 'src/main/java/com/lowagie/bc/asn1/BERInputStream.java')
| -rw-r--r-- | src/main/java/com/lowagie/bc/asn1/BERInputStream.java | 197 |
1 files changed, 197 insertions, 0 deletions
diff --git a/src/main/java/com/lowagie/bc/asn1/BERInputStream.java b/src/main/java/com/lowagie/bc/asn1/BERInputStream.java new file mode 100644 index 0000000..395c1e7 --- /dev/null +++ b/src/main/java/com/lowagie/bc/asn1/BERInputStream.java @@ -0,0 +1,197 @@ +package com.lowagie.bc.asn1;
+
+import java.io.ByteArrayOutputStream;
+import java.io.EOFException;
+import java.io.IOException;
+import java.io.InputStream;
+import java.util.Vector;
+
+public class BERInputStream
+ extends DERInputStream
+{
+ private DERObject END_OF_STREAM = new DERObject() {
+ void encode(
+ DEROutputStream out)
+ throws IOException
+ {
+ throw new IOException("Eeek!");
+ }
+
+ };
+ public BERInputStream(
+ InputStream is)
+ {
+ super(is);
+ }
+
+ /**
+ * read a string of bytes representing an indefinite length object.
+ */
+ private byte[] readIndefiniteLengthFully()
+ throws IOException
+ {
+ ByteArrayOutputStream bOut = new ByteArrayOutputStream();
+ int b, b1;
+
+ b1 = read();
+
+ while ((b = read()) >= 0)
+ {
+ if (b1 == 0 && b == 0)
+ {
+ break;
+ }
+
+ bOut.write(b1);
+ b1 = b;
+ }
+
+ return bOut.toByteArray();
+ }
+
+ private BERConstructedOctetString buildConstructedOctetString()
+ throws IOException
+ {
+ Vector octs = new Vector();
+
+ for (;;)
+ {
+ DERObject o = readObject();
+
+ if (o == END_OF_STREAM)
+ {
+ break;
+ }
+
+ octs.addElement(o);
+ }
+
+ return new BERConstructedOctetString(octs);
+ }
+
+ public DERObject readObject()
+ throws IOException
+ {
+ int tag = read();
+ if (tag == -1)
+ {
+ throw new EOFException();
+ }
+
+ int length = readLength();
+
+ if (length < 0) // indefinite length method
+ {
+ switch (tag)
+ {
+ case NULL:
+ return null;
+ case SEQUENCE | CONSTRUCTED:
+ BERConstructedSequence seq = new BERConstructedSequence();
+
+ for (;;)
+ {
+ DERObject obj = readObject();
+
+ if (obj == END_OF_STREAM)
+ {
+ break;
+ }
+
+ seq.addObject(obj);
+ }
+ return seq;
+ case OCTET_STRING | CONSTRUCTED:
+ return buildConstructedOctetString();
+ case SET | CONSTRUCTED:
+ ASN1EncodableVector v = new ASN1EncodableVector();
+
+ for (;;)
+ {
+ DERObject obj = readObject();
+
+ if (obj == END_OF_STREAM)
+ {
+ break;
+ }
+
+ v.add(obj);
+ }
+ return new BERSet(v);
+ default:
+ //
+ // with tagged object tag number is bottom 5 bits
+ //
+ if ((tag & TAGGED) != 0)
+ {
+ if ((tag & 0x1f) == 0x1f)
+ {
+ throw new IOException("unsupported high tag encountered");
+ }
+
+ //
+ // simple type - implicit... return an octet string
+ //
+ if ((tag & CONSTRUCTED) == 0)
+ {
+ byte[] bytes = readIndefiniteLengthFully();
+
+ return new BERTaggedObject(false, tag & 0x1f, new DEROctetString(bytes));
+ }
+
+ //
+ // either constructed or explicitly tagged
+ //
+ DERObject dObj = readObject();
+
+ if (dObj == END_OF_STREAM) // empty tag!
+ {
+ return new DERTaggedObject(tag & 0x1f);
+ }
+
+ DERObject next = readObject();
+
+ //
+ // explicitly tagged (probably!) - if it isn't we'd have to
+ // tell from the context
+ //
+ if (next == END_OF_STREAM)
+ {
+ return new BERTaggedObject(tag & 0x1f, dObj);
+ }
+
+ //
+ // another implicit object, we'll create a sequence...
+ //
+ seq = new BERConstructedSequence();
+
+ seq.addObject(dObj);
+
+ do
+ {
+ seq.addObject(next);
+ next = readObject();
+ }
+ while (next != END_OF_STREAM);
+
+ return new BERTaggedObject(false, tag & 0x1f, seq);
+ }
+
+ throw new IOException("unknown BER object encountered");
+ }
+ }
+ else
+ {
+ if (tag == 0 && length == 0) // end of contents marker.
+ {
+ return END_OF_STREAM;
+ }
+
+ byte[] bytes = new byte[length];
+
+ readFully(bytes);
+
+ return buildObject(tag, bytes);
+ }
+ }
+}
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