213 lines
7.5 KiB
C++
213 lines
7.5 KiB
C++
/*
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* Copyright (C) {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_PARS_H
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#define RBT_PARS_H
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#include "unicode/rbt.h"
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#include "uvector.h"
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#include "unicode/parseerr.h"
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class TransliterationRuleData;
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class UnicodeSet;
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class ParseData;
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class RuleHalf;
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class ParsePosition;
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class TransliteratorParser {
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/**
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* This is a reference to external data we don't own. This works because
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* we only hold this for the duration of the call to parse().
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*/
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const UnicodeString& rules;
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UTransDirection direction;
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TransliterationRuleData* data;
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/**
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* We use a single error code during parsing. Rather than pass it
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* through each API, we keep it here.
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*/
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UErrorCode status;
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/**
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* Pointer to user structure in which to return parse error information.
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* May be NULL.
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*/
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UParseError* parseError;
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/**
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* Temporary symbol table used during parsing.
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*/
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ParseData* parseData;
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/**
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* Temporary vector of set variables. When parsing is complete, this
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* is copied into the array data.setVariables. As with data.setVariables,
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* element 0 corresponds to character data.setVariablesBase.
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*/
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UVector setVariablesVector;
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/**
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* The next available stand-in for variables. This starts at some point in
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* the private use area (discovered dynamically) and increments up toward
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* <code>variableLimit</code>. At any point during parsing, available
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* variables are <code>variableNext..variableLimit-1</code>.
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*/
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UChar variableNext;
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/**
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* The last available stand-in for variables. This is discovered
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* dynamically. At any point during parsing, available variables are
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* <code>variableNext..variableLimit-1</code>.
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*/
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UChar variableLimit;
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/**
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* When we encounter an undefined variable, we do not immediately signal
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* an error, in case we are defining this variable, e.g., "$a = [a-z];".
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* Instead, we save the name of the undefined variable, and substitute
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* in the placeholder char variableLimit - 1, and decrement
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* variableLimit.
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*/
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UnicodeString undefinedVariableName;
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static const UnicodeString gOPERATORS;
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public:
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static TransliterationRuleData*
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parse(const UnicodeString& rules,
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UTransDirection direction,
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UParseError* parseError = 0);
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/**
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* Parse a given set of rules. Return up to three pieces of
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* parsed data. These are the header ::id block, the rule block,
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* and the footer ::id block. Any or all of these may be empty.
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* If the ::id blocks are empty, their corresponding parameters
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* are returned as the empty string. If there are no rules, the
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* TransliterationRuleData result is 0.
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* @param ruleDataResult caller owns the pointer stored here.
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* May be NULL.
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* @param headerRule string including semicolons for the header
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* ::id block. May be empty.
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* @param footerRule string including semicolons for the footer
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* ::id block. May be empty.
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*/
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static void parse(const UnicodeString& rules,
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UTransDirection direction,
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TransliterationRuleData*& ruleDataResult,
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UnicodeString& idBlockResult,
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int32_t& idSplitPointResult,
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UParseError* parseError,
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UErrorCode& ec);
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private:
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/**
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* @param rules list of rules, separated by newline characters
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* @exception IllegalArgumentException if there is a syntax error in the
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* rules
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*/
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TransliteratorParser(const UnicodeString& rules,
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UTransDirection direction,
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UParseError* parseError = 0);
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/**
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* Destructor.
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*/
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~TransliteratorParser();
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/**
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* Parse the given string as a sequence of rules, separated by newline
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* characters ('\n'), and cause this object to implement those rules. Any
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* previous rules are discarded. Typically this method is called exactly
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* once, during construction.
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* @exception IllegalArgumentException if there is a syntax error in the
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* rules
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*/
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void parseRules(UnicodeString& idBlockResult, int32_t& idSplitPointResult,
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int32_t& ruleCount);
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/**
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* MAIN PARSER. Parse the next rule in the given rule string, starting
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* at pos. Return the index after the last character parsed. Do not
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* parse characters at or after limit.
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*
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* Important: The character at pos must be a non-whitespace character
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* that is not the comment character.
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*
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* This method handles quoting, escaping, and whitespace removal. It
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* parses the end-of-rule character. It recognizes context and cursor
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* indicators. Once it does a lexical breakdown of the rule at pos, it
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* creates a rule object and adds it to our rule list.
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*/
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int32_t parseRule(int32_t pos, int32_t limit);
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/**
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* Called by main parser upon syntax error. Search the rule string
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* for the probable end of the rule. Of course, if the error is that
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* the end of rule marker is missing, then the rule end will not be found.
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* In any case the rule start will be correctly reported.
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* @param msg error description
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* @param rule pattern string
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* @param start position of first character of current rule
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*/
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int32_t syntaxError(int32_t parseErrorCode, const UnicodeString&, int32_t start);
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/**
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* Parse a UnicodeSet out, store it, and return the stand-in character
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* used to represent it.
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*/
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UChar parseSet(const UnicodeString& rule,
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ParsePosition& pos);
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/**
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* Append the value of the given variable name to the given
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* UnicodeString.
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*/
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void appendVariableDef(const UnicodeString& name,
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UnicodeString& buf);
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/**
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* Determines what part of the private use region of Unicode we can use for
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* variable stand-ins. The correct way to do this is as follows: Parse each
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* rule, and for forward and reverse rules, take the FROM expression, and
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* make a hash of all characters used. The TO expression should be ignored.
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* When done, everything not in the hash is available for use. In practice,
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* this method may employ some other algorithm for improved speed.
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*/
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void determineVariableRange(void);
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/**
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* Returns the index of a character, ignoring quoted text.
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* For example, in the string "abc'hide'h", the 'h' in "hide" will not be
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* found by a search for 'h'.
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* @param text text to be searched
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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 c character to search for
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* @return Offset of the first instance of c, or -1 if not found.
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*/
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static int32_t quotedIndexOf(const UnicodeString& text,
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int32_t start, int32_t limit,
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UChar c);
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friend class RuleHalf;
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// Disallowed methods; no impl.
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TransliteratorParser(const TransliteratorParser&);
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TransliteratorParser& operator=(const TransliteratorParser&);
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};
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#endif
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