diff options
Diffstat (limited to 'src/main/java/com/lowagie/bc/asn1/ASN1InputStream.java')
| -rw-r--r-- | src/main/java/com/lowagie/bc/asn1/ASN1InputStream.java | 450 |
1 files changed, 450 insertions, 0 deletions
diff --git a/src/main/java/com/lowagie/bc/asn1/ASN1InputStream.java b/src/main/java/com/lowagie/bc/asn1/ASN1InputStream.java new file mode 100644 index 0000000..1980af3 --- /dev/null +++ b/src/main/java/com/lowagie/bc/asn1/ASN1InputStream.java @@ -0,0 +1,450 @@ +package com.lowagie.bc.asn1;
+
+import java.io.ByteArrayInputStream;
+import java.io.ByteArrayOutputStream;
+import java.io.EOFException;
+import java.io.IOException;
+import java.io.InputStream;
+import java.util.Vector;
+
+/**
+ * a general purpose ASN.1 decoder - note: this class differs from the
+ * others in that it returns null after it has read the last object in
+ * the stream. If an ASN.1 NULL is encountered a DER/BER Null object is
+ * returned.
+ */
+public class ASN1InputStream
+ extends DERInputStream
+{
+ private DERObject END_OF_STREAM = new DERObject() {
+ void encode(
+ DEROutputStream out)
+ throws IOException
+ {
+ throw new IOException("Eeek!");
+ }
+
+ };
+ boolean eofFound = false;
+
+ public ASN1InputStream(
+ InputStream is)
+ {
+ super(is);
+ }
+
+ protected int readLength()
+ throws IOException
+ {
+ int length = read();
+ if (length < 0)
+ {
+ throw new IOException("EOF found when length expected");
+ }
+
+ if (length == 0x80)
+ {
+ return -1; // indefinite-length encoding
+ }
+
+ if (length > 127)
+ {
+ int size = length & 0x7f;
+
+ length = 0;
+ for (int i = 0; i < size; i++)
+ {
+ int next = read();
+
+ if (next < 0)
+ {
+ throw new IOException("EOF found reading length");
+ }
+
+ length = (length << 8) + next;
+ }
+ }
+
+ return length;
+ }
+
+ protected void readFully(
+ byte[] bytes)
+ throws IOException
+ {
+ int left = bytes.length;
+ int len;
+
+ if (left == 0)
+ {
+ return;
+ }
+
+ while ((len = read(bytes, bytes.length - left, left)) > 0)
+ {
+ if ((left -= len) == 0)
+ {
+ return;
+ }
+ }
+
+ if (left != 0)
+ {
+ throw new EOFException("EOF encountered in middle of object");
+ }
+ }
+
+ /**
+ * build an object given its tag and a byte stream to construct it
+ * from.
+ */
+ protected DERObject buildObject(
+ int tag,
+ byte[] bytes)
+ throws IOException
+ {
+ if ((tag & APPLICATION) != 0)
+ {
+ return new DERApplicationSpecific(tag, bytes);
+ }
+
+ switch (tag)
+ {
+ case NULL:
+ return new DERNull();
+ case SEQUENCE | CONSTRUCTED:
+ ByteArrayInputStream bIn = new ByteArrayInputStream(bytes);
+ ASN1InputStream aIn = new ASN1InputStream(bIn);
+ ASN1EncodableVector v = new ASN1EncodableVector();
+
+ DERObject obj = aIn.readObject();
+
+ while (obj != null)
+ {
+ v.add(obj);
+ obj = aIn.readObject();
+ }
+
+ return new DERSequence(v);
+ case SET | CONSTRUCTED:
+ bIn = new ByteArrayInputStream(bytes);
+ aIn = new ASN1InputStream(bIn);
+ v = new ASN1EncodableVector();
+
+ obj = aIn.readObject();
+
+ while (obj != null)
+ {
+ v.add(obj);
+ obj = aIn.readObject();
+ }
+
+ return new DERSet(v);
+ case BOOLEAN:
+ return new DERBoolean(bytes);
+ case INTEGER:
+ return new DERInteger(bytes);
+ case ENUMERATED:
+ return new DEREnumerated(bytes);
+ case OBJECT_IDENTIFIER:
+ return new DERObjectIdentifier(bytes);
+ case BIT_STRING:
+ int padBits = bytes[0];
+ byte[] data = new byte[bytes.length - 1];
+
+ System.arraycopy(bytes, 1, data, 0, bytes.length - 1);
+
+ return new DERBitString(data, padBits);
+ case UTF8_STRING:
+ return new DERUTF8String(bytes);
+ case PRINTABLE_STRING:
+ return new DERPrintableString(bytes);
+ case IA5_STRING:
+ return new DERIA5String(bytes);
+ case T61_STRING:
+ return new DERT61String(bytes);
+ case VISIBLE_STRING:
+ return new DERVisibleString(bytes);
+ case GENERAL_STRING:
+ return new DERGeneralString(bytes);
+ case UNIVERSAL_STRING:
+ return new DERUniversalString(bytes);
+ case BMP_STRING:
+ return new DERBMPString(bytes);
+ case OCTET_STRING:
+ return new DEROctetString(bytes);
+ case UTC_TIME:
+ return new DERUTCTime(bytes);
+ case GENERALIZED_TIME:
+ return new DERGeneralizedTime(bytes);
+ default:
+ //
+ // with tagged object tag number is bottom 5 bits
+ //
+ if ((tag & TAGGED) != 0)
+ {
+ int tagNo = tag & 0x1f;
+
+ if (tagNo == 0x1f)
+ {
+ int idx = 0;
+
+ tagNo = 0;
+
+ while ((bytes[idx] & 0x80) != 0)
+ {
+ tagNo |= (bytes[idx++] & 0x7f);
+ tagNo <<= 7;
+ }
+
+ tagNo |= (bytes[idx] & 0x7f);
+
+ byte[] tmp = bytes;
+
+ bytes = new byte[tmp.length - (idx + 1)];
+ System.arraycopy(tmp, idx + 1, bytes, 0, bytes.length);
+ }
+
+ if (bytes.length == 0) // empty tag!
+ {
+ if ((tag & CONSTRUCTED) == 0)
+ {
+ return new DERTaggedObject(false, tagNo, new DERNull());
+ }
+ else
+ {
+ return new DERTaggedObject(false, tagNo, new DERSequence());
+ }
+ }
+
+ //
+ // simple type - implicit... return an octet string
+ //
+ if ((tag & CONSTRUCTED) == 0)
+ {
+ return new DERTaggedObject(false, tagNo, new DEROctetString(bytes));
+ }
+
+ bIn = new ByteArrayInputStream(bytes);
+ aIn = new ASN1InputStream(bIn);
+
+ DEREncodable dObj = aIn.readObject();
+
+ //
+ // explicitly tagged (probably!) - if it isn't we'd have to
+ // tell from the context
+ //
+ if (aIn.available() == 0)
+ {
+ return new DERTaggedObject(tagNo, dObj);
+ }
+
+ //
+ // another implicit object, we'll create a sequence...
+ //
+ v = new ASN1EncodableVector();
+
+ while (dObj != null)
+ {
+ v.add(dObj);
+ dObj = aIn.readObject();
+ }
+
+ return new DERTaggedObject(false, tagNo, new DERSequence(v));
+ }
+
+ return new DERUnknownTag(tag, bytes);
+ }
+ }
+
+ /**
+ * 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)
+ {
+ if (eofFound)
+ {
+ throw new EOFException("attempt to read past end of file.");
+ }
+
+ eofFound = true;
+
+ return null;
+ }
+
+ int length = readLength();
+
+ if (length < 0) // indefinite length method
+ {
+ switch (tag)
+ {
+ case NULL:
+ return new BERNull();
+ case SEQUENCE | CONSTRUCTED:
+ ASN1EncodableVector v = new ASN1EncodableVector();
+
+ for (;;)
+ {
+ DERObject obj = readObject();
+
+ if (obj == END_OF_STREAM)
+ {
+ break;
+ }
+
+ v.add(obj);
+ }
+ return new BERSequence(v);
+ case SET | CONSTRUCTED:
+ v = new ASN1EncodableVector();
+
+ for (;;)
+ {
+ DERObject obj = readObject();
+
+ if (obj == END_OF_STREAM)
+ {
+ break;
+ }
+
+ v.add(obj);
+ }
+ return new BERSet(v);
+ case OCTET_STRING | CONSTRUCTED:
+ return buildConstructedOctetString();
+ default:
+ //
+ // with tagged object tag number is bottom 5 bits
+ //
+ if ((tag & TAGGED) != 0)
+ {
+ int tagNo = tag & 0x1f;
+
+ if (tagNo == 0x1f)
+ {
+ int b = read();
+
+ tagNo = 0;
+
+ while ((b >= 0) && ((b & 0x80) != 0))
+ {
+ tagNo |= (b & 0x7f);
+ tagNo <<= 7;
+ b = read();
+ }
+
+ tagNo |= (b & 0x7f);
+ }
+
+ //
+ // simple type - implicit... return an octet string
+ //
+ if ((tag & CONSTRUCTED) == 0)
+ {
+ byte[] bytes = readIndefiniteLengthFully();
+
+ return new BERTaggedObject(false, tagNo, new DEROctetString(bytes));
+ }
+
+ //
+ // either constructed or explicitly tagged
+ //
+ DERObject dObj = readObject();
+
+ if (dObj == END_OF_STREAM) // empty tag!
+ {
+ return new DERTaggedObject(tagNo);
+ }
+
+ 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(tagNo, dObj);
+ }
+
+ //
+ // another implicit object, we'll create a sequence...
+ //
+ v = new ASN1EncodableVector();
+
+ v.add(dObj);
+
+ do
+ {
+ v.add(next);
+ next = readObject();
+ }
+ while (next != END_OF_STREAM);
+
+ return new BERTaggedObject(false, tagNo, new BERSequence(v));
+ }
+
+ 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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