scuffed-code/icu4c/source/i18n/rbt_pars.h
2001-07-27 00:18:53 +00:00

219 lines
7.6 KiB
C++

/*
* Copyright (C) {1999}, International Business Machines Corporation and others. All Rights Reserved.
**********************************************************************
* Date Name Description
* 11/17/99 aliu Creation.
**********************************************************************
*/
#ifndef RBT_PARS_H
#define RBT_PARS_H
#include "unicode/rbt.h"
#include "uvector.h"
#include "unicode/parseerr.h"
class TransliterationRuleData;
class UnicodeMatcher;
class ParseData;
class RuleHalf;
class ParsePosition;
class TransliteratorParser {
/**
* This is a reference to external data we don't own. This works because
* we only hold this for the duration of the call to parse().
*/
const UnicodeString& rules;
UTransDirection direction;
TransliterationRuleData* data;
/**
* We use a single error code during parsing. Rather than pass it
* through each API, we keep it here.
*/
UErrorCode status;
/**
* Pointer to user structure in which to return parse error information.
* May be NULL.
*/
UParseError* parseError;
/**
* Temporary symbol table used during parsing.
*/
ParseData* parseData;
/**
* Temporary vector of matcher variables. When parsing is complete, this
* is copied into the array data.variables. As with data.variables,
* element 0 corresponds to character data.variablesBase.
*/
UVector variablesVector;
/**
* The next available stand-in for variables. This starts at some point in
* the private use area (discovered dynamically) and increments up toward
* <code>variableLimit</code>. At any point during parsing, available
* variables are <code>variableNext..variableLimit-1</code>.
*/
UChar variableNext;
/**
* The last available stand-in for variables. This is discovered
* dynamically. At any point during parsing, available variables are
* <code>variableNext..variableLimit-1</code>.
*/
UChar variableLimit;
/**
* When we encounter an undefined variable, we do not immediately signal
* an error, in case we are defining this variable, e.g., "$a = [a-z];".
* Instead, we save the name of the undefined variable, and substitute
* in the placeholder char variableLimit - 1, and decrement
* variableLimit.
*/
UnicodeString undefinedVariableName;
static const UnicodeString gOPERATORS;
public:
static TransliterationRuleData*
parse(const UnicodeString& rules,
UTransDirection direction,
UParseError* parseError = 0);
/**
* Parse a given set of rules. Return up to three pieces of
* parsed data. These are the header ::id block, the rule block,
* and the footer ::id block. Any or all of these may be empty.
* If the ::id blocks are empty, their corresponding parameters
* are returned as the empty string. If there are no rules, the
* TransliterationRuleData result is 0.
* @param ruleDataResult caller owns the pointer stored here.
* May be NULL.
* @param headerRule string including semicolons for the header
* ::id block. May be empty.
* @param footerRule string including semicolons for the footer
* ::id block. May be empty.
*/
static void parse(const UnicodeString& rules,
UTransDirection direction,
TransliterationRuleData*& ruleDataResult,
UnicodeString& idBlockResult,
int32_t& idSplitPointResult,
UParseError* parseError,
UErrorCode& ec);
private:
/**
* @param rules list of rules, separated by newline characters
* @exception IllegalArgumentException if there is a syntax error in the
* rules
*/
TransliteratorParser(const UnicodeString& rules,
UTransDirection direction,
UParseError* parseError = 0);
/**
* Destructor.
*/
~TransliteratorParser();
/**
* Parse the given string as a sequence of rules, separated by newline
* characters ('\n'), and cause this object to implement those rules. Any
* previous rules are discarded. Typically this method is called exactly
* once, during construction.
* @exception IllegalArgumentException if there is a syntax error in the
* rules
*/
void parseRules(UnicodeString& idBlockResult, int32_t& idSplitPointResult,
int32_t& ruleCount);
/**
* MAIN PARSER. Parse the next rule in the given rule string, starting
* at pos. Return the index after the last character parsed. Do not
* parse characters at or after limit.
*
* Important: The character at pos must be a non-whitespace character
* that is not the comment character.
*
* This method handles quoting, escaping, and whitespace removal. It
* parses the end-of-rule character. It recognizes context and cursor
* indicators. Once it does a lexical breakdown of the rule at pos, it
* creates a rule object and adds it to our rule list.
*/
int32_t parseRule(int32_t pos, int32_t limit);
/**
* Called by main parser upon syntax error. Search the rule string
* for the probable end of the rule. Of course, if the error is that
* the end of rule marker is missing, then the rule end will not be found.
* In any case the rule start will be correctly reported.
* @param msg error description
* @param rule pattern string
* @param start position of first character of current rule
*/
int32_t syntaxError(int32_t parseErrorCode, const UnicodeString&, int32_t start);
/**
* Parse a UnicodeSet out, store it, and return the stand-in character
* used to represent it.
*/
UChar parseSet(const UnicodeString& rule,
ParsePosition& pos);
/**
* Generate and return a stand-in for a new UnicodeMatcher. Store
* the matcher (adopt it).
*/
UChar generateStandInFor(UnicodeMatcher* adopted);
/**
* Append the value of the given variable name to the given
* UnicodeString.
*/
void appendVariableDef(const UnicodeString& name,
UnicodeString& buf);
/**
* Determines what part of the private use region of Unicode we can use for
* variable stand-ins. The correct way to do this is as follows: Parse each
* rule, and for forward and reverse rules, take the FROM expression, and
* make a hash of all characters used. The TO expression should be ignored.
* When done, everything not in the hash is available for use. In practice,
* this method may employ some other algorithm for improved speed.
*/
void determineVariableRange(void);
/**
* Returns the index of a character, ignoring quoted text.
* For example, in the string "abc'hide'h", the 'h' in "hide" will not be
* found by a search for 'h'.
* @param text text to be searched
* @param start the beginning index, inclusive; <code>0 <= start
* <= limit</code>.
* @param limit the ending index, exclusive; <code>start <= limit
* <= text.length()</code>.
* @param c character to search for
* @return Offset of the first instance of c, or -1 if not found.
*/
static int32_t quotedIndexOf(const UnicodeString& text,
int32_t start, int32_t limit,
UChar c);
friend class RuleHalf;
// Disallowed methods; no impl.
TransliteratorParser(const TransliteratorParser&);
TransliteratorParser& operator=(const TransliteratorParser&);
};
#endif