/*
 * Copyright (c) 2005, 2020, 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
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/*
/*
 *******************************************************************************
 * Copyright (C) 2003-2004, International Business Machines Corporation and         *
 * others. All Rights Reserved.                                                *
 *******************************************************************************
 */
//
// CHANGELOG
//      2005-05-19 Edward Wang
//          - copy this file from icu4jsrc_3_2/src/com/ibm/icu/text/StringPrep.java
//          - move from package com.ibm.icu.text to package sun.net.idn
//          - use ParseException instead of StringPrepParseException
//          - change 'Normalizer.getUnicodeVersion()' to 'NormalizerImpl.getUnicodeVersion()'
//          - remove all @deprecated tag to make compiler happy
//      2007-08-14 Martin Buchholz
//          - remove redundant casts
//
package jdk_internal.icu.text;

import java.io.BufferedInputStream;
import java.io.ByteArrayInputStream;
import java.io.IOException;
import java.io.InputStream;

import jdk_internal.bidi.Normalizer;
import jdk_internal.bidi.ParseException;
import jdk_internal.bidi.SunNormalizer;
import jdk_internal.icu.impl.CharTrie;
import jdk_internal.icu.impl.StringPrepDataReader;
import jdk_internal.icu.impl.Trie;
import jdk_internal.icu.lang.UCharacter;
import jdk_internal.icu.lang.UCharacterDirection;
import jdk_internal.icu.util.VersionInfo;

/**
 * StringPrep API implements the StingPrep framework as described by
 * <a href="http://www.ietf.org/rfc/rfc3454.txt">RFC 3454</a>. StringPrep
 * prepares Unicode strings for use in network protocols. Profiles of StingPrep
 * are set of rules and data according to which the Unicode Strings are
 * prepared. Each profiles contains tables which describe how a code point
 * should be treated. The tables are broadly classied into
 * <ul>
 * <li>Unassigned Table: Contains code points that are unassigned in the Unicode
 * Version supported by StringPrep. Currently RFC 3454 supports Unicode 3.2.
 * </li>
 * <li>Prohibited Table: Contains code points that are prohibted from the output
 * of the StringPrep processing function.</li>
 * <li>Mapping Table: Contains code ponts that are deleted from the output or
 * case mapped.</li>
 * </ul>
 *
 * The procedure for preparing Unicode strings:
 * <ol>
 * <li>Map: For each character in the input, check if it has a mapping and, if
 * so, replace it with its mapping.</li>
 * <li>Normalize: Possibly normalize the result of step 1 using Unicode
 * normalization.</li>
 * <li>Prohibit: Check for any characters that are not allowed in the output. If
 * any are found, return an error.</li>
 * <li>Check bidi: Possibly check for right-to-left characters, and if any are
 * found, make sure that the whole string satisfies the requirements for
 * bidirectional strings. If the string does not satisfy the requirements for
 * bidirectional strings, return an error.</li>
 * </ol>
 * 
 * @author Ram Viswanadha
 * @draft ICU 2.8
 */
public final class StringPrep {
	/**
	 * Option to prohibit processing of unassigned code points in the input
	 *
	 * @see #prepare
	 * @draft ICU 2.8
	 */
	public static final int DEFAULT = 0x0000;

	/**
	 * Option to allow processing of unassigned code points in the input
	 *
	 * @see #prepare
	 * @draft ICU 2.8
	 */
	public static final int ALLOW_UNASSIGNED = 0x0001;

	private static final int UNASSIGNED = 0x0000;
	private static final int MAP = 0x0001;
	private static final int PROHIBITED = 0x0002;
	private static final int DELETE = 0x0003;
	private static final int TYPE_LIMIT = 0x0004;

	private static final int NORMALIZATION_ON = 0x0001;
	private static final int CHECK_BIDI_ON = 0x0002;

	private static final int TYPE_THRESHOLD = 0xFFF0;
	private static final int MAX_INDEX_VALUE = 0x3FBF; /* 16139 */
	private static final int MAX_INDEX_TOP_LENGTH = 0x0003;

	/* indexes[] value names */
	private static final int INDEX_TRIE_SIZE = 0; /* number of bytes in normalization trie */
	private static final int INDEX_MAPPING_DATA_SIZE = 1; /* The array that contains the mapping */
	private static final int NORM_CORRECTNS_LAST_UNI_VERSION = 2; /*
																	 * The index of Unicode version of last entry in
																	 * NormalizationCorrections.txt
																	 */
	private static final int ONE_UCHAR_MAPPING_INDEX_START = 3; /*
																 * The starting index of 1 UChar mapping index in the
																 * mapping data array
																 */
	private static final int TWO_UCHARS_MAPPING_INDEX_START = 4; /*
																	 * The starting index of 2 UChars mapping index in
																	 * the mapping data array
																	 */
	private static final int THREE_UCHARS_MAPPING_INDEX_START = 5;
	private static final int FOUR_UCHARS_MAPPING_INDEX_START = 6;
	private static final int OPTIONS = 7; /* Bit set of options to turn on in the profile */
	private static final int INDEX_TOP = 16; /* changing this requires a new formatVersion */

	/**
	 * Default buffer size of datafile
	 */
	private static final int DATA_BUFFER_SIZE = 25000;

	/* Wrappers for Trie implementations */
	private static final class StringPrepTrieImpl implements Trie.DataManipulate {
		private CharTrie sprepTrie = null;

		/**
		 * Called by com.ibm.icu.util.Trie to extract from a lead surrogate's data the
		 * index array offset of the indexes for that lead surrogate.
		 * 
		 * @param property data value for a surrogate from the trie, including the
		 *                 folding offset
		 * @return data offset or 0 if there is no data for the lead surrogate
		 */
		public int getFoldingOffset(int value) {
			return value;
		}
	}

	// CharTrie implementation for reading the trie data
	private StringPrepTrieImpl sprepTrieImpl;
	// Indexes read from the data file
	private int[] indexes;
	// mapping data read from the data file
	private char[] mappingData;
	// format version of the data file
	private byte[] formatVersion;
	// the version of Unicode supported by the data file
	private VersionInfo sprepUniVer;
	// the Unicode version of last entry in the
	// NormalizationCorrections.txt file if normalization
	// is turned on
	private VersionInfo normCorrVer;
	// Option to turn on Normalization
	private boolean doNFKC;
	// Option to turn on checking for BiDi rules
	private boolean checkBiDi;

	private char getCodePointValue(int ch) {
		return sprepTrieImpl.sprepTrie.getCodePointValue(ch);
	}

	private static VersionInfo getVersionInfo(int comp) {
		int micro = comp & 0xFF;
		int milli = (comp >> 8) & 0xFF;
		int minor = (comp >> 16) & 0xFF;
		int major = (comp >> 24) & 0xFF;
		return VersionInfo.getInstance(major, minor, milli, micro);
	}

	private static VersionInfo getVersionInfo(byte[] version) {
		if (version.length != 4) {
			return null;
		}
		return VersionInfo.getInstance((int) version[0], (int) version[1], (int) version[2], (int) version[3]);
	}

	/**
	 * Creates an StringPrep object after reading the input stream. The object does
	 * not hold a reference to the input steam, so the stream can be closed after
	 * the method returns.
	 *
	 * @param inputStream The stream for reading the StringPrep profile binarySun
	 * @throws IOException
	 * @draft ICU 2.8
	 */
	public StringPrep(InputStream inputStream) throws IOException {

		BufferedInputStream b = new BufferedInputStream(inputStream, DATA_BUFFER_SIZE);

		StringPrepDataReader reader = new StringPrepDataReader(b);

		// read the indexes
		indexes = reader.readIndexes(INDEX_TOP);

		byte[] sprepBytes = new byte[indexes[INDEX_TRIE_SIZE]];

		// indexes[INDEX_MAPPING_DATA_SIZE] store the size of mappingData in bytes
		mappingData = new char[indexes[INDEX_MAPPING_DATA_SIZE] / 2];
		// load the rest of the data and initialize the data members
		reader.read(sprepBytes, mappingData);

		sprepTrieImpl = new StringPrepTrieImpl();
		sprepTrieImpl.sprepTrie = new CharTrie(new ByteArrayInputStream(sprepBytes), sprepTrieImpl);

		// get the data format version
		formatVersion = reader.getDataFormatVersion();

		// get the options
		doNFKC = ((indexes[OPTIONS] & NORMALIZATION_ON) > 0);
		checkBiDi = ((indexes[OPTIONS] & CHECK_BIDI_ON) > 0);
		sprepUniVer = getVersionInfo(reader.getUnicodeVersion());
		normCorrVer = getVersionInfo(indexes[NORM_CORRECTNS_LAST_UNI_VERSION]);
		VersionInfo normUniVer = UCharacter.getUnicodeVersion();
		if (normUniVer.compareTo(sprepUniVer) < 0 && /*
														 * the Unicode version of SPREP file must be less than the
														 * Unicode Vesion of the normalization data
														 */
				normUniVer.compareTo(normCorrVer) < 0
				&& /*
					 * the Unicode version of the NormalizationCorrections.txt file should be less
					 * than the Unicode Vesion of the normalization data
					 */
				((indexes[OPTIONS] & NORMALIZATION_ON) > 0) /* normalization turned on */
		) {
			throw new IOException("Normalization Correction version not supported");
		}
		b.close();
	}

	private static final class Values {
		boolean isIndex;
		int value;
		int type;

		public void reset() {
			isIndex = false;
			value = 0;
			type = -1;
		}
	}

	private static final void getValues(char trieWord, Values values) {
		values.reset();
		if (trieWord == 0) {
			/*
			 * Initial value stored in the mapping table just return TYPE_LIMIT .. so that
			 * the source codepoint is copied to the destination
			 */
			values.type = TYPE_LIMIT;
		} else if (trieWord >= TYPE_THRESHOLD) {
			values.type = (trieWord - TYPE_THRESHOLD);
		} else {
			/* get the type */
			values.type = MAP;
			/* ascertain if the value is index or delta */
			if ((trieWord & 0x02) > 0) {
				values.isIndex = true;
				values.value = trieWord >> 2; // mask off the lower 2 bits and shift

			} else {
				values.isIndex = false;
				values.value = (trieWord << 16) >> 16;
				values.value = (values.value >> 2);

			}

			if ((trieWord >> 2) == MAX_INDEX_VALUE) {
				values.type = DELETE;
				values.isIndex = false;
				values.value = 0;
			}
		}
	}

	private StringBuffer map(UCharacterIterator iter, int options) throws ParseException {

		Values val = new Values();
		char result = 0;
		int ch = UCharacterIterator.DONE;
		StringBuffer dest = new StringBuffer();
		boolean allowUnassigned = ((options & ALLOW_UNASSIGNED) > 0);

		while ((ch = iter.nextCodePoint()) != UCharacterIterator.DONE) {

			result = getCodePointValue(ch);
			getValues(result, val);

			// check if the source codepoint is unassigned
			if (val.type == UNASSIGNED && allowUnassigned == false) {
				throw new ParseException("An unassigned code point was found in the input " + iter.getText(),
						iter.getIndex());
			} else if ((val.type == MAP)) {
				int index, length;

				if (val.isIndex) {
					index = val.value;
					if (index >= indexes[ONE_UCHAR_MAPPING_INDEX_START]
							&& index < indexes[TWO_UCHARS_MAPPING_INDEX_START]) {
						length = 1;
					} else if (index >= indexes[TWO_UCHARS_MAPPING_INDEX_START]
							&& index < indexes[THREE_UCHARS_MAPPING_INDEX_START]) {
						length = 2;
					} else if (index >= indexes[THREE_UCHARS_MAPPING_INDEX_START]
							&& index < indexes[FOUR_UCHARS_MAPPING_INDEX_START]) {
						length = 3;
					} else {
						length = mappingData[index++];
					}
					/* copy mapping to destination */
					dest.append(mappingData, index, length);
					continue;

				} else {
					ch -= val.value;
				}
			} else if (val.type == DELETE) {
				// just consume the codepoint and contine
				continue;
			}
			// copy the source into destination
			UTF16.append(dest, ch);
		}

		return dest;
	}

	private StringBuffer normalize(StringBuffer src) {
		/*
		 * Option UNORM_BEFORE_PRI_29:
		 *
		 * IDNA as interpreted by IETF members (see unicode mailing list 2004H1)
		 * requires strict adherence to Unicode 3.2 normalization, including buggy
		 * composition from before fixing Public Review Issue #29. Note that this
		 * results in some valid but nonsensical text to be either corrupted or
		 * rejected, depending on the text. See
		 * http://www.unicode.org/review/resolved-pri.html#pri29 See unorm.cpp and
		 * cnormtst.c
		 */
		return new StringBuffer(
				SunNormalizer.normalize(src.toString(), Normalizer.Form.NFKC, SunNormalizer.UNICODE_3_2));
	}

	/*
	 * boolean isLabelSeparator(int ch){ int result = getCodePointValue(ch); if(
	 * (result & 0x07) == LABEL_SEPARATOR){ return true; } return false; }
	 */
	/*
	 * 1) Map -- For each character in the input, check if it has a mapping and, if
	 * so, replace it with its mapping.
	 * 
	 * 2) Normalize -- Possibly normalize the result of step 1 using Unicode
	 * normalization.
	 * 
	 * 3) Prohibit -- Check for any characters that are not allowed in the output.
	 * If any are found, return an error.
	 * 
	 * 4) Check bidi -- Possibly check for right-to-left characters, and if any are
	 * found, make sure that the whole string satisfies the requirements for
	 * bidirectional strings. If the string does not satisfy the requirements for
	 * bidirectional strings, return an error. [Unicode3.2] defines several
	 * bidirectional categories; each character has one bidirectional category
	 * assigned to it. For the purposes of the requirements below, an
	 * "RandALCat character" is a character that has Unicode bidirectional
	 * categories "R" or "AL"; an "LCat character" is a character that has Unicode
	 * bidirectional category "L". Note
	 * 
	 * 
	 * that there are many characters which fall in neither of the above
	 * definitions; Latin digits (<U+0030> through <U+0039>) are examples of this
	 * because they have bidirectional category "EN".
	 * 
	 * In any profile that specifies bidirectional character handling, all three of
	 * the following requirements MUST be met:
	 * 
	 * 1) The characters in section 5.8 MUST be prohibited.
	 * 
	 * 2) If a string contains any RandALCat character, the string MUST NOT contain
	 * any LCat character.
	 * 
	 * 3) If a string contains any RandALCat character, a RandALCat character MUST
	 * be the first character of the string, and a RandALCat character MUST be the
	 * last character of the string.
	 */
	/**
	 * Prepare the input buffer for use in applications with the given profile. This
	 * operation maps, normalizes(NFKC), checks for prohited and BiDi characters in
	 * the order defined by RFC 3454 depending on the options specified in the
	 * profile.
	 *
	 * @param src     A UCharacterIterator object containing the source string
	 * @param options A bit set of options:
	 *
	 *                - StringPrep.NONE Prohibit processing of unassigned code
	 *                points in the input
	 *
	 *                - StringPrep.ALLOW_UNASSIGNED Treat the unassigned code points
	 *                are in the input as normal Unicode code points.
	 *
	 * @return StringBuffer A StringBuffer containing the output
	 * @throws ParseException
	 * @draft ICU 2.8
	 */
	public StringBuffer prepare(UCharacterIterator src, int options) throws ParseException {

		// map
		StringBuffer mapOut = map(src, options);
		StringBuffer normOut = mapOut;// initialize

		if (doNFKC) {
			// normalize
			normOut = normalize(mapOut);
		}

		int ch;
		char result;
		UCharacterIterator iter = UCharacterIterator.getInstance(normOut);
		Values val = new Values();
		int direction = UCharacterDirection.CHAR_DIRECTION_COUNT,
				firstCharDir = UCharacterDirection.CHAR_DIRECTION_COUNT;
		int rtlPos = -1, ltrPos = -1;
		boolean rightToLeft = false, leftToRight = false;

		while ((ch = iter.nextCodePoint()) != UCharacterIterator.DONE) {
			result = getCodePointValue(ch);
			getValues(result, val);

			if (val.type == PROHIBITED) {
				throw new ParseException("A prohibited code point was found in the input" + iter.getText(), val.value);
			}

			direction = UCharacter.getDirection(ch);
			if (firstCharDir == UCharacterDirection.CHAR_DIRECTION_COUNT) {
				firstCharDir = direction;
			}
			if (direction == UCharacterDirection.LEFT_TO_RIGHT) {
				leftToRight = true;
				ltrPos = iter.getIndex() - 1;
			}
			if (direction == UCharacterDirection.RIGHT_TO_LEFT
					|| direction == UCharacterDirection.RIGHT_TO_LEFT_ARABIC) {
				rightToLeft = true;
				rtlPos = iter.getIndex() - 1;
			}
		}
		if (checkBiDi == true) {
			// satisfy 2
			if (leftToRight == true && rightToLeft == true) {
				throw new ParseException(
						"The input does not conform to the rules for BiDi code points." + iter.getText(),
						(rtlPos > ltrPos) ? rtlPos : ltrPos);
			}

			// satisfy 3
			if (rightToLeft == true && !((firstCharDir == UCharacterDirection.RIGHT_TO_LEFT
					|| firstCharDir == UCharacterDirection.RIGHT_TO_LEFT_ARABIC)
					&& (direction == UCharacterDirection.RIGHT_TO_LEFT
							|| direction == UCharacterDirection.RIGHT_TO_LEFT_ARABIC))) {
				throw new ParseException(
						"The input does not conform to the rules for BiDi code points." + iter.getText(),
						(rtlPos > ltrPos) ? rtlPos : ltrPos);
			}
		}
		return normOut;

	}
}