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	/*
	* Copyright (c) 2004, 2015, Oracle and/or its affiliates. All rights reserved.
	* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
	*
	* This code is free software; you can redistribute it and/or modify it
	* under the terms of the GNU General Public License version 2 only, as
	* published by the Free Software Foundation. Oracle designates this
	* particular file as subject to the "Classpath" exception as provided
	* by Oracle in the LICENSE file that accompanied this code.
	*
	* This code 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 General Public License
	* version 2 for more details (a copy is included in the LICENSE file that
	* accompanied this code).
	*
	* You should have received a copy of the GNU General Public License version
	* 2 along with this work; if not, write to the Free Software Foundation,
	* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
	*
	* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
	* or visit www.oracle.com if you need additional information or have any
	* questions.
	*/

	package sun.net.util;

	public class IPAddressUtil {
	private static final int INADDR4SZ = 4;
	private static final int INADDR16SZ = 16;
	private static final int INT16SZ = 2;

	/*
	* Converts IPv4 address in its textual presentation form
	* into its numeric binary form.
	*
	* @param src a String representing an IPv4 address in standard format
	* @return a byte array representing the IPv4 numeric address
	*/
	@SuppressWarnings("fallthrough")
	public static byte[] textToNumericFormatV4(String src)
	{
	byte[] res = new byte[INADDR4SZ];

	long tmpValue = 0;
	int currByte = 0;
	boolean newOctet = true;

	int len = src.length();
	if (len == 0 \|\| len > 15) {
	return null;
	}
	/*
	* When only one part is given, the value is stored directly in
	* the network address without any byte rearrangement.
	*
	* When a two part address is supplied, the last part is
	* interpreted as a 24-bit quantity and placed in the right
	* most three bytes of the network address. This makes the
	* two part address format convenient for specifying Class A
	* network addresses as net.host.
	*
	* When a three part address is specified, the last part is
	* interpreted as a 16-bit quantity and placed in the right
	* most two bytes of the network address. This makes the
	* three part address format convenient for specifying
	* Class B net- work addresses as 128.net.host.
	*
	* When four parts are specified, each is interpreted as a
	* byte of data and assigned, from left to right, to the
	* four bytes of an IPv4 address.
	*
	* We determine and parse the leading parts, if any, as single
	* byte values in one pass directly into the resulting byte[],
	* then the remainder is treated as a 8-to-32-bit entity and
	* translated into the remaining bytes in the array.
	*/
	for (int i = 0; i < len; i++) {
	char c = src.charAt(i);
	if (c == '.') {
	if (newOctet \|\| tmpValue < 0 \|\| tmpValue > 0xff \|\| currByte == 3) {
	return null;
	}
	res[currByte++] = (byte) (tmpValue & 0xff);
	tmpValue = 0;
	newOctet = true;
	} else {
	int digit = Character.digit(c, 10);
	if (digit < 0) {
	return null;
	}
	tmpValue *= 10;
	tmpValue += digit;
	newOctet = false;
	}
	}
	if (newOctet \|\| tmpValue < 0 \|\| tmpValue >= (1L << ((4 - currByte) * 8))) {
	return null;
	}
	switch (currByte) {
	case 0:
	res[0] = (byte) ((tmpValue >> 24) & 0xff);
	case 1:
	res[1] = (byte) ((tmpValue >> 16) & 0xff);
	case 2:
	res[2] = (byte) ((tmpValue >> 8) & 0xff);
	case 3:
	res[3] = (byte) ((tmpValue >> 0) & 0xff);
	}
	return res;
	}

	/*
	* Convert IPv6 presentation level address to network order binary form.
	* credit:
	* Converted from C code from Solaris 8 (inet_pton)
	*
	* Any component of the string following a per-cent % is ignored.
	*
	* @param src a String representing an IPv6 address in textual format
	* @return a byte array representing the IPv6 numeric address
	*/
	public static byte[] textToNumericFormatV6(String src)
	{
	// Shortest valid string is "::", hence at least 2 chars
	if (src.length() < 2) {
	return null;
	}

	int colonp;
	char ch;
	boolean saw_xdigit;
	int val;
	char[] srcb = src.toCharArray();
	byte[] dst = new byte[INADDR16SZ];

	int srcb_length = srcb.length;
	int pc = src.indexOf ('%');
	if (pc == srcb_length -1) {
	return null;
	}

	if (pc != -1) {
	srcb_length = pc;
	}

	colonp = -1;
	int i = 0, j = 0;
	/* Leading :: requires some special handling. */
	if (srcb[i] == ':')
	if (srcb[++i] != ':')
	return null;
	int curtok = i;
	saw_xdigit = false;
	val = 0;
	while (i < srcb_length) {
	ch = srcb[i++];
	int chval = Character.digit(ch, 16);
	if (chval != -1) {
	val <<= 4;
	val \|= chval;
	if (val > 0xffff)
	return null;
	saw_xdigit = true;
	continue;
	}
	if (ch == ':') {
	curtok = i;
	if (!saw_xdigit) {
	if (colonp != -1)
	return null;
	colonp = j;
	continue;
	} else if (i == srcb_length) {
	return null;
	}
	if (j + INT16SZ > INADDR16SZ)
	return null;
	dst[j++] = (byte) ((val >> 8) & 0xff);
	dst[j++] = (byte) (val & 0xff);
	saw_xdigit = false;
	val = 0;
	continue;
	}
	if (ch == '.' && ((j + INADDR4SZ) <= INADDR16SZ)) {
	String ia4 = src.substring(curtok, srcb_length);
	/* check this IPv4 address has 3 dots, ie. A.B.C.D */
	int dot_count = 0, index=0;
	while ((index = ia4.indexOf ('.', index)) != -1) {
	dot_count ++;
	index ++;
	}
	if (dot_count != 3) {
	return null;
	}
	byte[] v4addr = textToNumericFormatV4(ia4);
	if (v4addr == null) {
	return null;
	}
	for (int k = 0; k < INADDR4SZ; k++) {
	dst[j++] = v4addr[k];
	}
	saw_xdigit = false;
	break; /* '\0' was seen by inet_pton4(). */
	}
	return null;
	}
	if (saw_xdigit) {
	if (j + INT16SZ > INADDR16SZ)
	return null;
	dst[j++] = (byte) ((val >> 8) & 0xff);
	dst[j++] = (byte) (val & 0xff);
	}

	if (colonp != -1) {
	int n = j - colonp;

	if (j == INADDR16SZ)
	return null;
	for (i = 1; i <= n; i++) {
	dst[INADDR16SZ - i] = dst[colonp + n - i];
	dst[colonp + n - i] = 0;
	}
	j = INADDR16SZ;
	}
	if (j != INADDR16SZ)
	return null;
	byte[] newdst = convertFromIPv4MappedAddress(dst);
	if (newdst != null) {
	return newdst;
	} else {
	return dst;
	}
	}

	/**
	* @param src a String representing an IPv4 address in textual format
	* @return a boolean indicating whether src is an IPv4 literal address
	*/
	public static boolean isIPv4LiteralAddress(String src) {
	return textToNumericFormatV4(src) != null;
	}

	/**
	* @param src a String representing an IPv6 address in textual format
	* @return a boolean indicating whether src is an IPv6 literal address
	*/
	public static boolean isIPv6LiteralAddress(String src) {
	return textToNumericFormatV6(src) != null;
	}

	/*
	* Convert IPv4-Mapped address to IPv4 address. Both input and
	* returned value are in network order binary form.
	*
	* @param src a String representing an IPv4-Mapped address in textual format
	* @return a byte array representing the IPv4 numeric address
	*/
	public static byte[] convertFromIPv4MappedAddress(byte[] addr) {
	if (isIPv4MappedAddress(addr)) {
	byte[] newAddr = new byte[INADDR4SZ];
	System.arraycopy(addr, 12, newAddr, 0, INADDR4SZ);
	return newAddr;
	}
	return null;
	}

	/**
	* Utility routine to check if the InetAddress is an
	* IPv4 mapped IPv6 address.
	*
	* @return a <code>boolean</code> indicating if the InetAddress is
	* an IPv4 mapped IPv6 address; or false if address is IPv4 address.
	*/
	private static boolean isIPv4MappedAddress(byte[] addr) {
	if (addr.length < INADDR16SZ) {
	return false;
	}
	if ((addr[0] == 0x00) && (addr[1] == 0x00) &&
	(addr[2] == 0x00) && (addr[3] == 0x00) &&
	(addr[4] == 0x00) && (addr[5] == 0x00) &&
	(addr[6] == 0x00) && (addr[7] == 0x00) &&
	(addr[8] == 0x00) && (addr[9] == 0x00) &&
	(addr[10] == (byte)0xff) &&
	(addr[11] == (byte)0xff)) {
	return true;
	}
	return false;
	}
	}

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