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DSS Model contains the data model representation for DSS

There is a newer version: 6.0.d4j.2

package port.org.bouncycastle.asn1;

import java.io.ByteArrayInputStream;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.nio.channels.FileChannel;

class StreamUtil {
	private static final long MAX_MEMORY = Runtime.getRuntime().maxMemory();

	/**
	 * Find out possible longest length...
	 *
	 * @param in
	 *            input stream of interest
	 * @return length calculation or MAX_VALUE.
	 */
	static int findLimit(InputStream in) {
		if (in instanceof LimitedInputStream) {
			return ((LimitedInputStream) in).getRemaining();
		} else if (in instanceof ASN1InputStream) {
			return ((ASN1InputStream) in).getLimit();
		} else if (in instanceof ByteArrayInputStream) {
			return ((ByteArrayInputStream) in).available();
		} else if (in instanceof FileInputStream) {
			try {
				FileChannel channel = ((FileInputStream) in).getChannel();
				long size = (channel != null) ? channel.size() : Integer.MAX_VALUE;

				if (size < Integer.MAX_VALUE) {
					return (int) size;
				}
			} catch (IOException e) {
				// ignore - they'll find out soon enough!
			}
		}

		if (MAX_MEMORY > Integer.MAX_VALUE) {
			return Integer.MAX_VALUE;
		}

		return (int) MAX_MEMORY;
	}

	static int calculateBodyLength(int length) {
		int count = 1;

		if (length > 127) {
			int size = 1;
			int val = length;

			while ((val >>>= 8) != 0) {
				size++;
			}

			for (int i = (size - 1) * 8; i >= 0; i -= 8) {
				count++;
			}
		}

		return count;
	}

	static int calculateTagLength(int tagNo) throws IOException {
		int length = 1;

		if (tagNo >= 31) {
			if (tagNo < 128) {
				length++;
			} else {
				byte[] stack = new byte[5];
				int pos = stack.length;

				stack[--pos] = (byte) (tagNo & 0x7F);

				do {
					tagNo >>= 7;
			stack[--pos] = (byte) ((tagNo & 0x7F) | 0x80);
				} while (tagNo > 127);

				length += stack.length - pos;
			}
		}

		return length;
	}
}