| /* |
| ******************************************************************************* |
| * Copyright (C) 1996-2011, International Business Machines Corporation and * |
| * others. All Rights Reserved. * |
| ******************************************************************************* |
| */ |
| package com.ibm.icu.text; |
| |
| import java.util.HashMap; |
| import java.util.Map; |
| |
| /** |
| * <code>RuleBasedTransliterator</code> is a transliterator |
| * that reads a set of rules in order to determine how to perform |
| * translations. Rule sets are stored in resource bundles indexed by |
| * name. Rules within a rule set are separated by semicolons (';'). |
| * To include a literal semicolon, prefix it with a backslash ('\'). |
| * Unicode Pattern_White_Space is ignored. |
| * If the first non-blank character on a line is '#', |
| * the entire line is ignored as a comment. </p> |
| * |
| * <p>Each set of rules consists of two groups, one forward, and one |
| * reverse. This is a convention that is not enforced; rules for one |
| * direction may be omitted, with the result that translations in |
| * that direction will not modify the source text. In addition, |
| * bidirectional forward-reverse rules may be specified for |
| * symmetrical transformations.</p> |
| * |
| * <p><b>Rule syntax</b> </p> |
| * |
| * <p>Rule statements take one of the following forms: </p> |
| * |
| * <dl> |
| * <dt><code>$alefmadda=\u0622;</code></dt> |
| * <dd><strong>Variable definition.</strong> The name on the |
| * left is assigned the text on the right. In this example, |
| * after this statement, instances of the left hand name, |
| * "<code>$alefmadda</code>", will be replaced by |
| * the Unicode character U+0622. Variable names must begin |
| * with a letter and consist only of letters, digits, and |
| * underscores. Case is significant. Duplicate names cause |
| * an exception to be thrown, that is, variables cannot be |
| * redefined. The right hand side may contain well-formed |
| * text of any length, including no text at all ("<code>$empty=;</code>"). |
| * The right hand side may contain embedded <code>UnicodeSet</code> |
| * patterns, for example, "<code>$softvowel=[eiyEIY]</code>".</dd> |
| * <dd> </dd> |
| * <dt><code>ai>$alefmadda;</code></dt> |
| * <dd><strong>Forward translation rule.</strong> This rule |
| * states that the string on the left will be changed to the |
| * string on the right when performing forward |
| * transliteration.</dd> |
| * <dt> </dt> |
| * <dt><code>ai<$alefmadda;</code></dt> |
| * <dd><strong>Reverse translation rule.</strong> This rule |
| * states that the string on the right will be changed to |
| * the string on the left when performing reverse |
| * transliteration.</dd> |
| * </dl> |
| * |
| * <dl> |
| * <dt><code>ai<>$alefmadda;</code></dt> |
| * <dd><strong>Bidirectional translation rule.</strong> This |
| * rule states that the string on the right will be changed |
| * to the string on the left when performing forward |
| * transliteration, and vice versa when performing reverse |
| * transliteration.</dd> |
| * </dl> |
| * |
| * <p>Translation rules consist of a <em>match pattern</em> and an <em>output |
| * string</em>. The match pattern consists of literal characters, |
| * optionally preceded by context, and optionally followed by |
| * context. Context characters, like literal pattern characters, |
| * must be matched in the text being transliterated. However, unlike |
| * literal pattern characters, they are not replaced by the output |
| * text. For example, the pattern "<code>abc{def}</code>" |
| * indicates the characters "<code>def</code>" must be |
| * preceded by "<code>abc</code>" for a successful match. |
| * If there is a successful match, "<code>def</code>" will |
| * be replaced, but not "<code>abc</code>". The final '<code>}</code>' |
| * is optional, so "<code>abc{def</code>" is equivalent to |
| * "<code>abc{def}</code>". Another example is "<code>{123}456</code>" |
| * (or "<code>123}456</code>") in which the literal |
| * pattern "<code>123</code>" must be followed by "<code>456</code>". |
| * </p> |
| * |
| * <p>The output string of a forward or reverse rule consists of |
| * characters to replace the literal pattern characters. If the |
| * output string contains the character '<code>|</code>', this is |
| * taken to indicate the location of the <em>cursor</em> after |
| * replacement. The cursor is the point in the text at which the |
| * next replacement, if any, will be applied. The cursor is usually |
| * placed within the replacement text; however, it can actually be |
| * placed into the precending or following context by using the |
| * special character '<code>@</code>'. Examples:</p> |
| * |
| * <blockquote> |
| * <p><code>a {foo} z > | @ bar; # foo -> bar, move cursor |
| * before a<br> |
| * {foo} xyz > bar @@|; # foo -> bar, cursor between |
| * y and z</code></p> |
| * </blockquote> |
| * |
| * <p><b>UnicodeSet</b></p> |
| * |
| * <p><code>UnicodeSet</code> patterns may appear anywhere that |
| * makes sense. They may appear in variable definitions. |
| * Contrariwise, <code>UnicodeSet</code> patterns may themselves |
| * contain variable references, such as "<code>$a=[a-z];$not_a=[^$a]</code>", |
| * or "<code>$range=a-z;$ll=[$range]</code>".</p> |
| * |
| * <p><code>UnicodeSet</code> patterns may also be embedded directly |
| * into rule strings. Thus, the following two rules are equivalent:</p> |
| * |
| * <blockquote> |
| * <p><code>$vowel=[aeiou]; $vowel>'*'; # One way to do this<br> |
| * [aeiou]>'*'; |
| * # |
| * Another way</code></p> |
| * </blockquote> |
| * |
| * <p>See {@link UnicodeSet} for more documentation and examples.</p> |
| * |
| * <p><b>Segments</b></p> |
| * |
| * <p>Segments of the input string can be matched and copied to the |
| * output string. This makes certain sets of rules simpler and more |
| * general, and makes reordering possible. For example:</p> |
| * |
| * <blockquote> |
| * <p><code>([a-z]) > $1 $1; |
| * # |
| * double lowercase letters<br> |
| * ([:Lu:]) ([:Ll:]) > $2 $1; # reverse order of Lu-Ll pairs</code></p> |
| * </blockquote> |
| * |
| * <p>The segment of the input string to be copied is delimited by |
| * "<code>(</code>" and "<code>)</code>". Up to |
| * nine segments may be defined. Segments may not overlap. In the |
| * output string, "<code>$1</code>" through "<code>$9</code>" |
| * represent the input string segments, in left-to-right order of |
| * definition.</p> |
| * |
| * <p><b>Anchors</b></p> |
| * |
| * <p>Patterns can be anchored to the beginning or the end of the text. This is done with the |
| * special characters '<code>^</code>' and '<code>$</code>'. For example:</p> |
| * |
| * <blockquote> |
| * <p><code>^ a > 'BEG_A'; # match 'a' at start of text<br> |
| * a > 'A'; # match other instances |
| * of 'a'<br> |
| * z $ > 'END_Z'; # match 'z' at end of text<br> |
| * z > 'Z'; # match other instances |
| * of 'z'</code></p> |
| * </blockquote> |
| * |
| * <p>It is also possible to match the beginning or the end of the text using a <code>UnicodeSet</code>. |
| * This is done by including a virtual anchor character '<code>$</code>' at the end of the |
| * set pattern. Although this is usually the match chafacter for the end anchor, the set will |
| * match either the beginning or the end of the text, depending on its placement. For |
| * example:</p> |
| * |
| * <blockquote> |
| * <p><code>$x = [a-z$]; # match 'a' through 'z' OR anchor<br> |
| * $x 1 > 2; # match '1' after a-z or at the start<br> |
| * 3 $x > 4; # match '3' before a-z or at the end</code></p> |
| * </blockquote> |
| * |
| * <p><b>Example</b> </p> |
| * |
| * <p>The following example rules illustrate many of the features of |
| * the rule language. </p> |
| * |
| * <table border="0" cellpadding="4"> |
| * <tr> |
| * <td valign="top">Rule 1.</td> |
| * <td valign="top" nowrap><code>abc{def}>x|y</code></td> |
| * </tr> |
| * <tr> |
| * <td valign="top">Rule 2.</td> |
| * <td valign="top" nowrap><code>xyz>r</code></td> |
| * </tr> |
| * <tr> |
| * <td valign="top">Rule 3.</td> |
| * <td valign="top" nowrap><code>yz>q</code></td> |
| * </tr> |
| * </table> |
| * |
| * <p>Applying these rules to the string "<code>adefabcdefz</code>" |
| * yields the following results: </p> |
| * |
| * <table border="0" cellpadding="4"> |
| * <tr> |
| * <td valign="top" nowrap><code>|adefabcdefz</code></td> |
| * <td valign="top">Initial state, no rules match. Advance |
| * cursor.</td> |
| * </tr> |
| * <tr> |
| * <td valign="top" nowrap><code>a|defabcdefz</code></td> |
| * <td valign="top">Still no match. Rule 1 does not match |
| * because the preceding context is not present.</td> |
| * </tr> |
| * <tr> |
| * <td valign="top" nowrap><code>ad|efabcdefz</code></td> |
| * <td valign="top">Still no match. Keep advancing until |
| * there is a match...</td> |
| * </tr> |
| * <tr> |
| * <td valign="top" nowrap><code>ade|fabcdefz</code></td> |
| * <td valign="top">...</td> |
| * </tr> |
| * <tr> |
| * <td valign="top" nowrap><code>adef|abcdefz</code></td> |
| * <td valign="top">...</td> |
| * </tr> |
| * <tr> |
| * <td valign="top" nowrap><code>adefa|bcdefz</code></td> |
| * <td valign="top">...</td> |
| * </tr> |
| * <tr> |
| * <td valign="top" nowrap><code>adefab|cdefz</code></td> |
| * <td valign="top">...</td> |
| * </tr> |
| * <tr> |
| * <td valign="top" nowrap><code>adefabc|defz</code></td> |
| * <td valign="top">Rule 1 matches; replace "<code>def</code>" |
| * with "<code>xy</code>" and back up the cursor |
| * to before the '<code>y</code>'.</td> |
| * </tr> |
| * <tr> |
| * <td valign="top" nowrap><code>adefabcx|yz</code></td> |
| * <td valign="top">Although "<code>xyz</code>" is |
| * present, rule 2 does not match because the cursor is |
| * before the '<code>y</code>', not before the '<code>x</code>'. |
| * Rule 3 does match. Replace "<code>yz</code>" |
| * with "<code>q</code>".</td> |
| * </tr> |
| * <tr> |
| * <td valign="top" nowrap><code>adefabcxq|</code></td> |
| * <td valign="top">The cursor is at the end; |
| * transliteration is complete.</td> |
| * </tr> |
| * </table> |
| * |
| * <p>The order of rules is significant. If multiple rules may match |
| * at some point, the first matching rule is applied. </p> |
| * |
| * <p>Forward and reverse rules may have an empty output string. |
| * Otherwise, an empty left or right hand side of any statement is a |
| * syntax error. </p> |
| * |
| * <p>Single quotes are used to quote any character other than a |
| * digit or letter. To specify a single quote itself, inside or |
| * outside of quotes, use two single quotes in a row. For example, |
| * the rule "<code>'>'>o''clock</code>" changes the |
| * string "<code>></code>" to the string "<code>o'clock</code>". |
| * </p> |
| * |
| * <p><b>Notes</b> </p> |
| * |
| * <p>While a RuleBasedTransliterator is being built, it checks that |
| * the rules are added in proper order. For example, if the rule |
| * "a>x" is followed by the rule "ab>y", |
| * then the second rule will throw an exception. The reason is that |
| * the second rule can never be triggered, since the first rule |
| * always matches anything it matches. In other words, the first |
| * rule <em>masks</em> the second rule. </p> |
| * |
| * <p>Copyright (c) IBM Corporation 1999-2000. All rights reserved.</p> |
| * |
| * @author Alan Liu |
| * @internal |
| * @deprecated This API is ICU internal only. |
| */ |
| public class RuleBasedTransliterator extends Transliterator { |
| |
| private Data data; |
| |
| /** |
| * Constructs a new transliterator from the given rules. |
| * @param rules rules, separated by ';' |
| * @param direction either FORWARD or REVERSE. |
| * @exception IllegalArgumentException if rules are malformed |
| * or direction is invalid. |
| * @internal |
| * @deprecated This API is ICU internal only. |
| */ |
| /*public RuleBasedTransliterator(String ID, String rules, int direction, |
| UnicodeFilter filter) { |
| super(ID, filter); |
| if (direction != FORWARD && direction != REVERSE) { |
| throw new IllegalArgumentException("Invalid direction"); |
| } |
| |
| TransliteratorParser parser = new TransliteratorParser(); |
| parser.parse(rules, direction); |
| if (parser.idBlockVector.size() != 0 || |
| parser.compoundFilter != null) { |
| throw new IllegalArgumentException("::ID blocks illegal in RuleBasedTransliterator constructor"); |
| } |
| |
| data = (Data)parser.dataVector.get(0); |
| setMaximumContextLength(data.ruleSet.getMaximumContextLength()); |
| }*/ |
| |
| /** |
| * Constructs a new transliterator from the given rules in the |
| * <code>FORWARD</code> direction. |
| * @param rules rules, separated by ';' |
| * @exception IllegalArgumentException if rules are malformed |
| * or direction is invalid. |
| * @internal |
| * @deprecated This API is ICU internal only. |
| */ |
| /*public RuleBasedTransliterator(String ID, String rules) { |
| this(ID, rules, FORWARD, null); |
| }*/ |
| |
| RuleBasedTransliterator(String ID, Data data, UnicodeFilter filter) { |
| super(ID, filter); |
| this.data = data; |
| setMaximumContextLength(data.ruleSet.getMaximumContextLength()); |
| } |
| |
| /** |
| * Implements {@link Transliterator#handleTransliterate}. |
| * @internal |
| * @deprecated This API is ICU internal only. |
| */ |
| protected void handleTransliterate(Replaceable text, |
| Position index, boolean incremental) { |
| /* We keep start and limit fixed the entire time, |
| * relative to the text -- limit may move numerically if text is |
| * inserted or removed. The cursor moves from start to limit, with |
| * replacements happening under it. |
| * |
| * Example: rules 1. ab>x|y |
| * 2. yc>z |
| * |
| * |eabcd start - no match, advance cursor |
| * e|abcd match rule 1 - change text & adjust cursor |
| * ex|ycd match rule 2 - change text & adjust cursor |
| * exz|d no match, advance cursor |
| * exzd| done |
| */ |
| |
| /* A rule like |
| * a>b|a |
| * creates an infinite loop. To prevent that, we put an arbitrary |
| * limit on the number of iterations that we take, one that is |
| * high enough that any reasonable rules are ok, but low enough to |
| * prevent a server from hanging. The limit is 16 times the |
| * number of characters n, unless n is so large that 16n exceeds a |
| * uint32_t. |
| */ |
| synchronized(data) { |
| int loopCount = 0; |
| int loopLimit = (index.limit - index.start) << 4; |
| if (loopLimit < 0) { |
| loopLimit = 0x7FFFFFFF; |
| } |
| |
| while (index.start < index.limit && |
| loopCount <= loopLimit && |
| data.ruleSet.transliterate(text, index, incremental)) { |
| ++loopCount; |
| } |
| } |
| } |
| |
| |
| static class Data { |
| public Data() { |
| variableNames = new HashMap<String, char[]>(); |
| ruleSet = new TransliterationRuleSet(); |
| } |
| |
| /** |
| * Rule table. May be empty. |
| */ |
| public TransliterationRuleSet ruleSet; |
| |
| /** |
| * Map variable name (String) to variable (char[]). A variable name |
| * corresponds to zero or more characters, stored in a char[] array in |
| * this hash. One or more of these chars may also correspond to a |
| * UnicodeSet, in which case the character in the char[] in this hash is |
| * a stand-in: it is an index for a secondary lookup in |
| * data.variables. The stand-in also represents the UnicodeSet in |
| * the stored rules. |
| */ |
| Map<String, char[]> variableNames; |
| |
| /** |
| * Map category variable (Character) to UnicodeMatcher or UnicodeReplacer. |
| * Variables that correspond to a set of characters are mapped |
| * from variable name to a stand-in character in data.variableNames. |
| * The stand-in then serves as a key in this hash to lookup the |
| * actual UnicodeSet object. In addition, the stand-in is |
| * stored in the rule text to represent the set of characters. |
| * variables[i] represents character (variablesBase + i). |
| */ |
| Object[] variables; |
| |
| /** |
| * The character that represents variables[0]. Characters |
| * variablesBase through variablesBase + |
| * variables.length - 1 represent UnicodeSet objects. |
| */ |
| char variablesBase; |
| |
| /** |
| * Return the UnicodeMatcher represented by the given character, or |
| * null if none. |
| */ |
| public UnicodeMatcher lookupMatcher(int standIn) { |
| int i = standIn - variablesBase; |
| return (i >= 0 && i < variables.length) |
| ? (UnicodeMatcher) variables[i] : null; |
| } |
| |
| /** |
| * Return the UnicodeReplacer represented by the given character, or |
| * null if none. |
| */ |
| public UnicodeReplacer lookupReplacer(int standIn) { |
| int i = standIn - variablesBase; |
| return (i >= 0 && i < variables.length) |
| ? (UnicodeReplacer) variables[i] : null; |
| } |
| } |
| |
| |
| /** |
| * Return a representation of this transliterator as source rules. |
| * These rules will produce an equivalent transliterator if used |
| * to construct a new transliterator. |
| * @param escapeUnprintable if TRUE then convert unprintable |
| * character to their hex escape representations, \\uxxxx or |
| * \\Uxxxxxxxx. Unprintable characters are those other than |
| * U+000A, U+0020..U+007E. |
| * @return rules string |
| * @internal |
| * @deprecated This API is ICU internal only. |
| */ |
| public String toRules(boolean escapeUnprintable) { |
| return data.ruleSet.toRules(escapeUnprintable); |
| } |
| |
| // /** |
| // * Return the set of all characters that may be modified by this |
| // * Transliterator, ignoring the effect of our filter. |
| // * @internal |
| // * @deprecated This API is ICU internal only. |
| // */ |
| // protected UnicodeSet handleGetSourceSet() { |
| // return data.ruleSet.getSourceTargetSet(false, unicodeFilter); |
| // } |
| // |
| // /** |
| // * Returns the set of all characters that may be generated as |
| // * replacement text by this transliterator. |
| // * @internal |
| // * @deprecated This API is ICU internal only. |
| // */ |
| // public UnicodeSet getTargetSet() { |
| // return data.ruleSet.getSourceTargetSet(true, unicodeFilter); |
| // } |
| |
| /** |
| * @internal |
| */ |
| @Override |
| public void addSourceTargetSet(UnicodeSet filter, UnicodeSet sourceSet, UnicodeSet targetSet) { |
| data.ruleSet.addSourceTargetSet(filter, sourceSet, targetSet); |
| } |
| |
| /** |
| * Temporary hack for registry problem. Needs to be replaced by better architecture. |
| * @internal |
| * @deprecated This API is ICU internal only. |
| */ |
| public Transliterator safeClone() { |
| UnicodeFilter filter = getFilter(); |
| if (filter != null && filter instanceof UnicodeSet) { |
| filter = new UnicodeSet((UnicodeSet)filter); |
| } |
| return new RuleBasedTransliterator(getID(), data, filter); |
| } |
| } |
| |
| |
