src/jlibrtp/StaticProcs.java
changeset 13 e684f11070d5
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/jlibrtp/StaticProcs.java	Sat Mar 14 22:15:41 2009 +0100
@@ -0,0 +1,270 @@
+/**
+ * Java RTP Library (jlibrtp)
+ * Copyright (C) 2006 Arne Kepp
+ * 
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ * 
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
+ */
+package jlibrtp;
+
+/** 
+ * Generic functions for converting between unsigned integers and byte[]s.
+ *
+ * @author Arne Kepp
+ */
+public class StaticProcs {
+
+	/** 
+	 * Converts an integer into an array of bytes. 
+	 * Primarily used for 16 bit unsigned integers, ignore the first two octets.
+	 * 
+	 * @param i a 16 bit unsigned integer in an int
+	 * @return byte[2] representing the integer as unsigned, most significant bit first. 
+	 */
+	public static byte[] uIntIntToByteWord(int i) {		
+		byte[] byteWord = new byte[2];
+		byteWord[0] = (byte) ((i >> 8) & 0x000000FF);
+		byteWord[1] = (byte) (i & 0x00FF);
+		return byteWord;
+	}
+	
+	/** 
+	 * Converts an unsigned 32 bit integer, stored in a long, into an array of bytes.
+	 * 
+	 * @param j a long
+	 * @return byte[4] representing the unsigned integer, most significant bit first. 
+	 */
+	public static byte[] uIntLongToByteWord(long j) {
+		int i = (int) j;
+		byte[] byteWord = new byte[4];
+		byteWord[0] = (byte) ((i >>> 24) & 0x000000FF);
+		byteWord[1] = (byte) ((i >> 16) & 0x000000FF);
+		byteWord[2] = (byte) ((i >> 8) & 0x000000FF);
+		byteWord[3] = (byte) (i & 0x00FF);
+		return byteWord;
+	}
+	
+	/** 
+	 * Combines two bytes (most significant bit first) into a 16 bit unsigned integer.
+	 * 
+	 * @param index of most significant byte
+	 * @return int with the 16 bit unsigned integer
+	 */
+	public static int bytesToUIntInt(byte[] bytes, int index) {
+		int accum = 0;
+		int i = 1;
+		for (int shiftBy = 0; shiftBy < 16; shiftBy += 8 ) {
+			accum |= ( (long)( bytes[index + i] & 0xff ) ) << shiftBy;
+			i--;
+		}
+		return accum;
+	}
+	
+	/** 
+	 * Combines four bytes (most significant bit first) into a 32 bit unsigned integer.
+	 * 
+	 * @param bytes
+	 * @param index of most significant byte
+	 * @return long with the 32 bit unsigned integer
+	 */
+	public static long bytesToUIntLong(byte[] bytes, int index) {
+		long accum = 0;
+		int i = 3;
+		for (int shiftBy = 0; shiftBy < 32; shiftBy += 8 ) {
+			accum |= ( (long)( bytes[index + i] & 0xff ) ) << shiftBy;
+			i--;
+		}
+		return accum;
+	}
+	
+	/**
+	 * Converts an arbitrary number of bytes, assumed to represent an unsigned integer,
+	 * to a Java long
+	 */
+	/*public static long bytesToUintLong(byte[] bytes, int firstByte, int lastByte) {
+		long accum = 0;
+		int i = lastByte - firstByte;
+		if(i > 7) {
+			System.out.println("!!!! StaticProcs.bytesToUintLong() Can't convert more than 63 bits!");
+			return -1;
+		}
+		int stop = (i+1)*8;
+		
+		for (int shiftBy = 0; shiftBy < stop; shiftBy += 8 ) {
+			accum |= ( (long)( bytes[firstByte + i] & 0xff ) ) << shiftBy;
+			i--;
+		}
+		return accum;
+	}*/
+	
+	/**
+	 * Converts an arbitrary number of bytes, assumed to represent an unsigned integer,
+	 * to a Java int
+	 */
+	/*	public static int bytesToUintInt(byte[] bytes, int firstByte, int lastByte) {
+		int accum = 0;
+		int i = lastByte - firstByte;
+		if(i > 3) {
+			System.out.println("!!!! StaticProcs.bytesToUintLong() Can't convert more than 31 bits!");
+			return -1;
+		}
+		int stop = (i+1)*8;
+		
+		for (int shiftBy = 0; shiftBy < stop; shiftBy += 8 ) {
+			accum |= ( (long)( bytes[firstByte + i] & 0xff ) ) << shiftBy;
+			i--;
+		}
+		return accum;
+	}*/
+	
+	/**
+	 * Recreates a UNIX timestamp based on the NTP representation used
+	 * in RTCP SR packets
+	 * 
+	 * @param ntpTs1 from RTCP SR packet
+	 * @param ntpTs2 from RTCP SR packet
+	 * @return the UNIX timestamp
+	 */
+	public static long undoNtpMess(long ntpTs1, long ntpTs2) {		
+		long timeVal = (ntpTs1 - 2208988800L)*1000;
+			
+		double tmp = (1000.0*(double)ntpTs2)/((double)4294967295L);
+		long ms = (long) tmp;
+		//System.out.println(" timeVal: " +Long.toString(timeVal)+ " ms " + Long.toString(ms));
+		timeVal += ms;
+		
+		return timeVal;
+	}
+	
+
+	
+	/** 
+	 * Get the bits of a byte
+	 * 
+	 * @param aByte the byte you wish to convert
+	 * @return a String of 1's and 0's
+	 */
+	public static String bitsOfByte(byte aByte) {
+		int temp;
+		String out = "";
+		for(int i=7; i>=0; i--) {
+			temp = (aByte >>> i);
+			temp &= 0x0001;
+			out += (""+temp);
+		}
+		return out;
+	}
+	
+	/** 
+	 * Get the hex representation of a byte
+	 * 
+	 * @param aByte the byte you wish to convert
+	 * @return a String of two chars 0-1,A-F
+	 */
+	public static String hexOfByte(byte aByte) {
+		String out = "";
+
+		for(int i=0; i<2; i++) {
+			int temp = (int) aByte;
+			if(temp < 0) {
+				temp +=256;
+			}
+			if(i == 0) {
+				temp = temp/16;
+			} else {
+				temp = temp%16;
+			}
+			
+			if( temp > 9) {
+				switch(temp) {
+				case 10: out += "A"; break;
+				case 11: out += "B"; break;
+				case 12: out += "C"; break;
+				case 13: out += "D"; break;
+				case 14: out += "E"; break;
+				case 15: out += "F"; break;
+				}
+			} else {
+				out += Integer.toString(temp);
+			}
+		}
+		return out;
+	}
+	
+	/** 
+	 * Get the hex representation of a byte
+	 * 
+	 * @param hex 4 bytes  the byte you wish to convert
+	 * @return a String of two chars 0-1,A-F
+	 */
+	public static byte byteOfHex(byte[] hex) {
+		byte retByte = 0;
+		Byte tmp;
+		int val = 0;
+		
+		// First 4 bits
+		tmp = hex[0];
+		val = tmp.intValue();
+		if(val > 64) {
+			// Letter
+			val -= 55;
+		} else {
+			// Number
+			val -= 48;
+		}
+		retByte = ((byte) (val << 4));
+		
+		// Last 4 bits
+		tmp = hex[1];
+		val = tmp.intValue();
+		if(val > 64) {
+			// Letter
+			val -= 55;
+		} else {
+			// Number
+			val -= 48;
+		}
+		retByte |= ((byte) val);
+		
+		return retByte;
+	}
+	
+	
+	/** 
+	 * Print the bits of a byte to standard out. For debugging.
+	 * 
+	 * @param aByte the byte you wish to print out.
+	 */
+	public static void printBits(byte aByte) {
+		int temp;
+		for(int i=7; i>=0; i--) {
+			temp = (aByte >>> i);
+			temp &= 0x0001;
+			System.out.print(""+temp);
+		}
+		System.out.println();
+	}
+	
+	public static String bitsOfBytes(byte[] bytes) {
+		String str = "";
+		//Expensive, but who cares
+		for(int i=0; i<bytes.length; i++ ) {
+			str += bitsOfByte(bytes[i]) + " ";
+			if((i + 1) % 4 == 0)
+				str += "\n";
+		}
+		
+		return str;
+	}
+}
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