379 lines
16 KiB
C++
379 lines
16 KiB
C++
/*
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* Copyright © {1999}, International Business Machines Corporation and others. All Rights Reserved.
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**********************************************************************
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* Date Name Description
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* 11/17/99 aliu Creation.
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**********************************************************************
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*/
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#ifndef RBT_RULE_H
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#define RBT_RULE_H
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#include "unicode/unistr.h"
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class Replaceable;
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class TransliterationRuleData;
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class UnicodeFilter;
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/**
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* A transliteration rule used by
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* <code>RuleBasedTransliterator</code>.
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* <code>TransliterationRule</code> is an immutable object.
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*
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* <p>A rule consists of an input pattern and an output string. When
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* the input pattern is matched, the output string is emitted. The
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* input pattern consists of zero or more characters which are matched
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* exactly (the key) and optional context. Context must match if it
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* is specified. Context may be specified before the key, after the
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* key, or both. The key, preceding context, and following context
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* may contain variables. Variables represent a set of Unicode
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* characters, such as the letters <i>a</i> through <i>z</i>.
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* Variables are detected by looking up each character in a supplied
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* variable list to see if it has been so defined.
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*
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* @author Alan Liu
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*/
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class TransliterationRule {
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public:
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/**
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* Constants returned by <code>getMatchDegree()</code> indicating
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* the degree of match between the text and this rule.
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* @see #getMatchDegree
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*/
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enum {
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/**
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* Constant returned by <code>getMatchDegree()</code>
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* indicating a mismatch between the text and this rule. One
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* or more characters of the context or key do not match the
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* text.
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*/
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MISMATCH,
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/**
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* Constant returned by <code>getMatchDegree()</code>
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* indicating a partial match between the text and this rule.
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* All characters of the text match the corresponding context
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* or key, but more characters are required for a complete
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* match. There are some key or context characters at the end
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* of the pattern that remain unmatched because the text isn't
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* long enough.
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*/
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PARTIAL_MATCH,
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/**
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* Constant returned by <code>getMatchDegree()</code>
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* indicating a complete match between the text and this rule.
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* The text matches all context and key characters.
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*/
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FULL_MATCH
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};
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private:
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/**
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* The string that must be matched.
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*/
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UnicodeString key;
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/**
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* The string that is emitted if the key, anteContext, and postContext
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* are matched.
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*/
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UnicodeString output;
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/**
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* The string that must match before the key. If empty, then
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* there is no matching requirement before the key.
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*/
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UnicodeString anteContext;
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/**
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* The string that must match after the key. If empty, then there
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* is no matching requirement after the key.
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*/
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UnicodeString postContext;
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/**
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* The position of the cursor after emitting the output string, from 0 to
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* output.length(). For most rules with no special cursor specification,
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* the cursorPos is output.length().
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*/
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int32_t cursorPos;
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/**
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* A string used to implement masks().
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* @see #freeze
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*/
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UnicodeString* maskKey;
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public:
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/**
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* Construct a new rule with the given key, output text, and other
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* attributes. Zero, one, or two context strings may be specified. A
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* cursor position may be specified for the output text.
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* @param key the string to match
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* @param output the string to produce when the <code>key</code> is seen
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* @param anteContext if not null and not empty, then it must be matched
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* before the <code>key</code>
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* @param postContext if not null and not empty, then it must be matched
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* after the <code>key</code>
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* @param cursorPos a position for the cursor after the <code>output</code>
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* is emitted. If less than zero, then the cursor is placed after the
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* <code>output</code>; that is, -1 is equivalent to
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* <code>output.length()</code>. If greater than
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* <code>output.length()</code> then an exception is thrown.
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* @exception IllegalArgumentException if the cursor position is out of
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* range.
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*/
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TransliterationRule(const UnicodeString& theKey,
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const UnicodeString& theOutput,
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const UnicodeString& theAnteContext,
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const UnicodeString& thePostContext,
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int32_t theCursorPos,
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UErrorCode &status);
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/**
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* Destructor.
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*/
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virtual ~TransliterationRule();
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/**
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* Return the length of the key. Equivalent to <code>getKey().length()</code>.
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* @return the length of the match key.
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*/
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virtual int32_t getKeyLength(void) const;
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/**
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* Return the key.
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* @return the match key.
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*/
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virtual const UnicodeString& getKey(void) const;
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/**
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* Return the output string.
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* @return the output string.
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*/
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virtual const UnicodeString& getOutput(void) const;
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/**
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* Return the position of the cursor within the output string.
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* @return a value from 0 to <code>getOutput().length()</code>, inclusive.
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*/
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virtual int32_t getCursorPos(void) const;
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/**
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* Return the preceding context length. This method is needed to
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* support the <code>Transliterator</code> method
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* <code>getMaximumContextLength()</code>.
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*/
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virtual int32_t getAnteContextLength(void) const;
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/**
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* Return true if this rule masks another rule. If r1 masks r2 then
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* r1 matches any input string that r2 matches. If r1 masks r2 and r2 masks
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* r1 then r1 == r2. Examples: "a>x" masks "ab>y". "a>x" masks "a[b]>y".
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* "[c]a>x" masks "[dc]a>y".
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*
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* <p>This method must not be called after freeze() is called.
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*/
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virtual bool_t masks(const TransliterationRule& r2) const;
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/**
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* Free up space. Once this method is called, masks() must NOT be called.
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* If it is called, an exception will be thrown.
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*/
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virtual void freeze(void);
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/**
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* Return true if this rule matches the given text. The text being matched
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* occupies a virtual buffer consisting of the contents of
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* <code>result</code> concatenated to a substring of <code>text</code>.
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* The substring is specified by <code>start</code> and <code>limit</code>.
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* The value of <code>cursor</code> is an index into this virtual buffer,
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* from 0 to the length of the buffer. In terms of the parameters,
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* <code>cursor</code> must be between 0 and <code>result.length() + limit -
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* start</code>.
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* @param text the untranslated text
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* @param start the beginning index, inclusive; <code>0 <= start
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* <= limit</code>.
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* @param limit the ending index, exclusive; <code>start <= limit
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* <= text.length()</code>.
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* @param result translated text so far
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* @param cursor position at which to translate next, an offset into result.
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* If greater than or equal to result.length(), represents offset start +
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* cursor - result.length() into text.
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* @param filter the filter. Any character for which
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* <tt>filter.isIn()</tt> returns <tt>false</tt> will not be
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* altered by this transliterator. If <tt>filter</tt> is
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* <tt>null</tt> then no filtering is applied.
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*/
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virtual bool_t matches(const UnicodeString& text,
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int32_t start, int32_t limit,
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const UnicodeString& result,
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int32_t cursor,
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const TransliterationRuleData& data,
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const UnicodeFilter* filter) const;
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/**
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* Return true if this rule matches the given text.
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* @param text the text, both translated and untranslated
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* @param start the beginning index, inclusive; <code>0 <= start
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* <= limit</code>.
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* @param limit the ending index, exclusive; <code>start <= limit
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* <= text.length()</code>.
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* @param cursor position at which to translate next, representing offset
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* into text. This value must be between <code>start</code> and
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* <code>limit</code>.
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* @param filter the filter. Any character for which
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* <tt>filter.isIn()</tt> returns <tt>false</tt> will not be
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* altered by this transliterator. If <tt>filter</tt> is
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* <tt>null</tt> then no filtering is applied.
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*/
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virtual bool_t matches(const Replaceable& text,
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int32_t start, int32_t limit,
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int32_t cursor,
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const TransliterationRuleData& data,
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const UnicodeFilter* filter) const;
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/**
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* Return the degree of match between this rule and the given text. The
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* degree of match may be mismatch, a partial match, or a full match. A
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* mismatch means at least one character of the text does not match the
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* context or key. A partial match means some context and key characters
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* match, but the text is not long enough to match all of them. A full
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* match means all context and key characters match.
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* @param text the text, both translated and untranslated
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* @param start the beginning index, inclusive; <code>0 <= start
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* <= limit</code>.
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* @param limit the ending index, exclusive; <code>start <= limit
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* <= text.length()</code>.
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* @param cursor position at which to translate next, representing offset
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* into text. This value must be between <code>start</code> and
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* <code>limit</code>.
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* @param filter the filter. Any character for which
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* <tt>filter.isIn()</tt> returns <tt>false</tt> will not be
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* altered by this transliterator. If <tt>filter</tt> is
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* <tt>null</tt> then no filtering is applied.
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* @return one of <code>MISMATCH</code>, <code>PARTIAL_MATCH</code>, or
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* <code>FULL_MATCH</code>.
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* @see #MISMATCH
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* @see #PARTIAL_MATCH
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* @see #FULL_MATCH
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*/
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virtual int32_t getMatchDegree(const Replaceable& text,
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int32_t start, int32_t limit,
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int32_t cursor,
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const TransliterationRuleData& data,
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const UnicodeFilter* filter) const;
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/**
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* Return true if a template matches the text. The entire length of the
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* template is compared to the text at the cursor. As in
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* <code>matches()</code>, the text being matched occupies a virtual buffer
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* consisting of the contents of <code>result</code> concatenated to a
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* substring of <code>text</code>. See <code>matches()</code> for details.
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* @param text the untranslated text
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* @param start the beginning index, inclusive; <code>0 <= start
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* <= limit</code>.
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* @param limit the ending index, exclusive; <code>start <= limit
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* <= text.length()</code>.
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* @param result translated text so far
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* @param cursor position at which to translate next, an offset into result.
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* If greater than or equal to result.length(), represents offset start +
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* cursor - result.length() into text.
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* @param templ the text to match against. All characters must match.
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* @param data a dictionary of variables mapping <code>Character</code>
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* to <code>UnicodeSet</code>
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* @param filter the filter. Any character for which
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* <tt>filter.isIn()</tt> returns <tt>false</tt> will not be
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* altered by this transliterator. If <tt>filter</tt> is
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* <tt>null</tt> then no filtering is applied.
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* @return true if there is a match
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*/
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virtual bool_t regionMatches(const UnicodeString& text,
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int32_t start, int32_t limit,
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const UnicodeString& result,
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int32_t cursor,
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const UnicodeString& templ,
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const TransliterationRuleData& data,
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const UnicodeFilter* filter) const;
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/**
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* Return true if a template matches the text. The entire length of the
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* template is compared to the text at the cursor.
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* @param text the text, both translated and untranslated
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* @param start the beginning index, inclusive; <code>0 <= start
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* <= limit</code>.
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* @param limit the ending index, exclusive; <code>start <= limit
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* <= text.length()</code>.
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* @param cursor position at which to translate next, representing offset
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* into text. This value must be between <code>start</code> and
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* <code>limit</code>.
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* @param templ the text to match against. All characters must match.
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* @param data a dictionary of variables mapping <code>Character</code>
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* to <code>UnicodeSet</code>
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* @param filter the filter. Any character for which
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* <tt>filter.isIn()</tt> returns <tt>false</tt> will not be
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* altered by this transliterator. If <tt>filter</tt> is
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* <tt>null</tt> then no filtering is applied.
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* @return true if there is a match
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*/
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virtual bool_t regionMatches(const Replaceable& text,
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int32_t start, int32_t limit,
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int32_t cursor,
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const UnicodeString& templ,
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const TransliterationRuleData& data,
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const UnicodeFilter* filter) const;
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/**
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* Return the number of characters of the text that match this rule. If
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* there is a mismatch, return -1. If the text is not long enough to match
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* any characters, return 0.
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* @param text the text, both translated and untranslated
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* @param start the beginning index, inclusive; <code>0 <= start
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* <= limit</code>.
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* @param limit the ending index, exclusive; <code>start <= limit
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* <= text.length()</code>.
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* @param cursor position at which to translate next, representing offset
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* into text. This value must be between <code>start</code> and
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* <code>limit</code>.
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* @param templ the text to match against. All characters must match.
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* @param data a dictionary of variables mapping <code>Character</code>
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* to <code>UnicodeSet</code>
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* @param filter the filter. Any character for which
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* <tt>filter.isIn()</tt> returns <tt>false</tt> will not be
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* altered by this transliterator. If <tt>filter</tt> is
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* <tt>null</tt> then no filtering is applied.
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* @return -1 if there is a mismatch, 0 if the text is not long enough to
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* match any characters, otherwise the number of characters of text that
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* match this rule.
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*/
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virtual int32_t getRegionMatchLength(const Replaceable& text, int32_t start,
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int32_t limit, int32_t cursor,
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const UnicodeString& templ,
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const TransliterationRuleData& data,
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const UnicodeFilter* filter) const;
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/**
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* Return true if the given key matches the given text. This method
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* accounts for the fact that the key character may represent a character
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* set. Note that the key and text characters may not be interchanged
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* without altering the results.
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* @param keyChar a character in the match key
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* @param textChar a character in the text being transliterated
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* @param data a dictionary of variables mapping <code>Character</code>
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* to <code>UnicodeSet</code>
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* @param filter the filter. Any character for which
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* <tt>filter.isIn()</tt> returns <tt>false</tt> will not be
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* altered by this transliterator. If <tt>filter</tt> is
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* <tt>null</tt> then no filtering is applied.
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*/
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virtual bool_t charMatches(UChar keyChar, UChar textChar,
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const TransliterationRuleData& data,
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const UnicodeFilter* filter) const;
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};
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#endif
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