scuffed-code/icu4c/source/i18n/rbt_pars.h
2001-10-23 23:26:47 +00:00

327 lines
11 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 "unicode/parseerr.h"
#include "unicode/unorm.h"
U_NAMESPACE_BEGIN
class TransliterationRuleData;
class UnicodeMatcher;
class ParseData;
class RuleHalf;
class ParsePosition;
class UVector;
class TransliteratorParser {
public:
/**
* PUBLIC data member containing the parsed data object, or null if
* there were no rules.
*/
TransliterationRuleData* data;
/**
* PUBLIC data member.
* The block of ::IDs, both at the top and at the bottom.
* Inserted into these may be additional rules at the
* idSplitPoint.
*/
UnicodeString idBlock;
/**
* PUBLIC data member.
* In a compound RBT, the index at which the RBT rules are
* inserted into the ID block. Index 0 means before any IDs
* in the block. Index idBlock.length() means after all IDs
* in the block. Index is a string index.
*/
int32_t idSplitPoint;
/**
* PUBLIC data member containing the parsed compound filter, if any.
*/
UnicodeSet* compoundFilter;
private:
// The number of rules parsed. This tells us if there were
// any actual transliterator rules, or if there were just ::ID
// block IDs.
int32_t ruleCount;
UTransDirection direction;
/**
* We use a single error code during parsing. Rather than pass it
* through each API, we keep it here.
*/
UErrorCode status;
/**
* Parse error information.
*/
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;
/**
* The stand-in character for the 'dot' set, represented by '.' in
* patterns. This is allocated the first time it is needed, and
* reused thereafter.
*/
UChar dotStandIn;
public:
/**
* Constructor.
*/
TransliteratorParser();
/**
* 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 after construction.
*
* Parse the given rules, in the given direction. After this call
* returns, query the public data members for results. The caller
* owns the 'data' and 'compoundFilter' data members after this
* call returns.
*/
void parse(const UnicodeString& rules,
UTransDirection direction,
UParseError& pe,
UErrorCode& ec);
/**
* Return the compound filter parsed by parse(). Caller owns result.
*/
UnicodeSet* orphanCompoundFilter();
/**
* Return the data object parsed by parse(). Caller owns result.
*/
TransliterationRuleData* orphanData();
private:
void parseRules(const UnicodeString& rules,
UTransDirection direction);
/**
* 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(const UnicodeString& rule, int32_t pos, int32_t limit);
/**
* Set the variable range to [start, end] (inclusive).
*/
void setVariableRange(int32_t start, int32_t end);
/**
* Set the maximum backup to 'backup', in response to a pragma
* statement.
*/
void pragmaMaximumBackup(int32_t backup);
/**
* Begin normalizing all rules using the given mode, in response
* to a pragma statement.
*/
void pragmaNormalizeRules(UNormalizationMode mode);
/**
* Return true if the given rule looks like a pragma.
* @param pos offset to the first non-whitespace character
* of the rule.
* @param limit pointer past the last character of the rule.
*/
static UBool resemblesPragma(const UnicodeString& rule, int32_t pos, int32_t limit);
/**
* Parse a pragma. This method assumes resemblesPragma() has
* already returned true.
* @param pos offset to the first non-whitespace character
* of the rule.
* @param limit pointer past the last character of the rule.
* @return the position index after the final ';' of the pragma,
* or -1 on failure.
*/
int32_t parsePragma(const UnicodeString& rule, 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(UErrorCode 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);
/**
* Return the stand-in for the dot set. It is allocated the first
* time and reused thereafter.
*/
UChar getDotStandIn();
/**
* Append the value of the given variable name to the given
* UnicodeString.
*/
void appendVariableDef(const UnicodeString& name,
UnicodeString& buf);
/**
* Return a stand-in character that refers to the given segments.
* @param r a reference number >= 1
* @return a stand-in for the given segment reference
*/
UChar getSegmentStandin(int32_t r);
/**
* 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);
//------------------------------------------------------------
// Utility methods -- temporarily here
//------------------------------------------------------------
/**
* Skip over a sequence of zero or more white space characters
* at pos. Return the index of the first non-white-space character
* at or after pos, or str.length(), if there is none.
*/
static int32_t skipWhitespace(const UnicodeString& str, int32_t pos);
/**
* Parse a pattern string starting at offset pos. Keywords are
* matched case-insensitively. Spaces may be skipped and may be
* optional or required. Integer values may be parsed, and if
* they are, they will be returned in the given array. If
* successful, the offset of the next non-space character is
* returned. On failure, -1 is returned.
* @param pattern must only contain lowercase characters, which
* will match their uppercase equivalents as well. A space
* character matches one or more required spaces. A '~' character
* matches zero or more optional spaces. A '#' character matches
* an integer and stores it in parsedInts, which the caller must
* ensure has enough capacity.
* @param parsedInts array to receive parsed integers. Caller
* must ensure that parsedInts.length is >= the number of '#'
* signs in 'pattern'.
* @return the position after the last character parsed, or -1 if
* the parse failed
*/
static int32_t parsePattern(const UnicodeString& rule, int32_t pos, int32_t limit,
const UnicodeString& pattern, int32_t* parsedInts);
/**
* Parse an integer at pos, either of the form \d+ or of the form
* 0x[0-9A-Fa-f]+ or 0[0-7]+, that is, in standard decimal, hex,
* or octal format.
* @param pos INPUT-OUTPUT parameter. On input, the first
* character to parse. On output, the character after the last
* parsed character.
*/
static int32_t parseInteger(const UnicodeString& rule, int32_t& pos, int32_t limit);
friend class RuleHalf;
// Disallowed methods; no impl.
TransliteratorParser(const TransliteratorParser&);
TransliteratorParser& operator=(const TransliteratorParser&);
};
U_NAMESPACE_END
#endif