243 lines
7.6 KiB
C++
243 lines
7.6 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 "unicode/parseerr.h"
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U_NAMESPACE_BEGIN
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class TransliterationRuleData;
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class UnicodeMatcher;
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class ParseData;
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class RuleHalf;
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class ParsePosition;
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class UVector;
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class TransliteratorParser {
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public:
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/**
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* PUBLIC data member containing the parsed data object, or null if
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* there were no rules.
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*/
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TransliterationRuleData* data;
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/**
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* PUBLIC data member.
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* The block of ::IDs, both at the top and at the bottom.
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* Inserted into these may be additional rules at the
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* idSplitPoint.
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*/
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UnicodeString idBlock;
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/**
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* PUBLIC data member.
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* In a compound RBT, the index at which the RBT rules are
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* inserted into the ID block. Index 0 means before any IDs
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* in the block. Index idBlock.length() means after all IDs
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* in the block. Index is a string index.
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*/
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int32_t idSplitPoint;
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/**
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* PUBLIC data member containing the parsed compound filter, if any.
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*/
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UnicodeSet* compoundFilter;
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private:
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// The number of rules parsed. This tells us if there were
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// any actual transliterator rules, or if there were just ::ID
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// block IDs.
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int32_t ruleCount;
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UTransDirection direction;
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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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* Parse error information.
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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 matcher variables. When parsing is complete, this
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* is copied into the array data.variables. As with data.variables,
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* element 0 corresponds to character data.variablesBase.
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*/
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UVector* variablesVector;
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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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public:
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/**
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* Constructor.
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*/
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TransliteratorParser();
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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 after construction.
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*
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* Parse the given rules, in the given direction. After this call
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* returns, query the public data members for results. The caller
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* owns the 'data' and 'compoundFilter' data members after this
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* call returns.
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*/
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void parse(const UnicodeString& rules,
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UTransDirection direction,
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UParseError& pe,
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UErrorCode& ec);
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/**
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* Return the compound filter parsed by parse(). Caller owns result.
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*/
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UnicodeSet* orphanCompoundFilter();
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/**
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* Return the data object parsed by parse(). Caller owns result.
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*/
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TransliterationRuleData* orphanData();
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private:
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void parseRules(const UnicodeString& rules,
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UTransDirection direction);
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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(const UnicodeString& rule, 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(UErrorCode 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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* Generate and return a stand-in for a new UnicodeMatcher. Store
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* the matcher (adopt it).
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*/
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UChar generateStandInFor(UnicodeMatcher* adopted);
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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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* Return a stand-in character that refers to the given segments.
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* @param r a reference number >= 1
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* @return a stand-in for the given segment reference
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*/
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UChar getSegmentStandin(int32_t r);
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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(const UnicodeString&);
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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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U_NAMESPACE_END
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#endif
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