/*
**********************************************************************
* Copyright (c) 2002, International Business Machines Corporation
* and others. All Rights Reserved.
**********************************************************************
* Date Name Description
* 01/28/2002 aliu Creation.
**********************************************************************
*/
#ifndef TRIDPARS_H
#define TRIDPARS_H
#include "unicode/utypes.h"
#include "unicode/unistr.h"
U_NAMESPACE_BEGIN
class Transliterator;
class UnicodeSet;
class UVector;
/**
* Parsing component for transliterator IDs. This class contains only
* static members; it cannot be instantiated. Methods in this class
* parse various ID formats, including the following:
*
* A basic ID, which contains source, target, and variant, but no
* filter and no explicit inverse. Examples include
* "Latin-Greek/UNGEGN" and "Null".
*
* A single ID, which is a basic ID plus optional filter and optional
* explicit inverse. Examples include "[a-zA-Z] Latin-Greek" and
* "Lower (Upper)".
*
* A compound ID, which is a sequence of one or more single IDs,
* separated by semicolons, with optional forward and reverse global
* filters. The global filters are UnicodeSet patterns prepended or
* appended to the IDs, separated by semicolons. An appended filter
* must be enclosed in parentheses and applies in the reverse
* direction.
*
* @author Alan Liu
*/
class TransliteratorIDParser {
public:
/**
* A structure containing the parsed data of a filtered ID, that
* is, a basic ID optionally with a filter.
*
* 'source' and 'target' will always be non-null. The 'variant'
* will be non-null only if a non-empty variant was parsed.
*
* 'sawSource' is true if there was an explicit source in the
* parsed id. If there was no explicit source, then an implied
* source of ANY is returned and 'sawSource' is set to false.
*
* 'filter' is the parsed filter pattern, or null if there was no
* filter.
*/
class Specs {
public:
UnicodeString source; // not null
UnicodeString target; // not null
UnicodeString variant; // may be null
UnicodeString filter; // may be null
UBool sawSource;
Specs(const UnicodeString& s, const UnicodeString& t,
const UnicodeString& v, UBool sawS,
const UnicodeString& f);
};
/**
* A structure containing the canonicalized data of a filtered ID,
* that is, a basic ID optionally with a filter.
*
* 'canonID' is always non-null. It may be the empty string "".
* It is the id that should be assigned to the created
* transliterator. It _cannot_ be instantiated directly.
*
* 'basicID' is always non-null and non-empty. It is always of
* the form S-T or S-T/V. It is designed to be fed to low-level
* instantiation code that only understands these two formats.
*
* 'filter' may be null, if there is none, or non-null and
* non-empty.
*/
class SingleID {
public:
UnicodeString canonID;
UnicodeString basicID;
UnicodeString filter;
SingleID(const UnicodeString& c, const UnicodeString& b,
const UnicodeString& f);
SingleID(const UnicodeString& c, const UnicodeString& b);
Transliterator* createInstance();
};
/**
* Parse a filter ID, that is, an ID of the general form
* "[f1] s1-t1/v1", with the filters optional, and the variants optional.
* @param id the id to be parsed
* @param pos INPUT-OUTPUT parameter. On input, the position of
* the first character to parse. On output, the position after
* the last character parsed.
* @return a SingleID object or null if the parse fails
*/
static SingleID* parseFilterID(const UnicodeString& id, int32_t& pos);
/**
* Parse a single ID, that is, an ID of the general form
* "[f1] s1-t1/v1 ([f2] s2-t3/v2)", with the parenthesized element
* optional, the filters optional, and the variants optional.
* @param id the id to be parsed
* @param pos INPUT-OUTPUT parameter. On input, the position of
* the first character to parse. On output, the position after
* the last character parsed.
* @param dir the direction. If the direction is REVERSE then the
* SingleID is constructed for the reverse direction.
* @return a SingleID object or null
*/
static SingleID* parseSingleID(const UnicodeString& id, int32_t& pos,
int32_t dir);
/**
* Parse a global filter of the form "[f]" or "([f])", depending
* on 'withParens'.
* @param id the pattern the parse
* @param pos INPUT-OUTPUT parameter. On input, the position of
* the first character to parse. On output, the position after
* the last character parsed.
* @param dir the direction.
* @param withParens INPUT-OUTPUT parameter. On entry, if
* withParens[0] is 0, then parens are disallowed. If it is 1,
* then parens are requires. If it is -1, then parens are
* optional, and the return result will be set to 0 or 1.
* @param canonID OUTPUT parameter. The pattern for the filter
* added to the canonID, either at the end, if dir is FORWARD, or
* at the start, if dir is REVERSE. The pattern will be enclosed
* in parentheses if appropriate, and will be suffixed with an
* ID_DELIM character. May be null.
* @return a UnicodeSet object or null. A non-null results
* indicates a successful parse, regardless of whether the filter
* applies to the given direction. The caller should discard it
* if withParens != (dir == REVERSE).
*/
static UnicodeSet* parseGlobalFilter(const UnicodeString& id, int32_t& pos,
int32_t dir,
int32_t& withParens,
UnicodeString* canonID);
/**
* Parse a compound ID, consisting of an optional forward global
* filter, a separator, one or more single IDs delimited by
* separators, an an optional reverse global filter. The
* separator is a semicolon. The global filters are UnicodeSet
* patterns. The reverse global filter must be enclosed in
* parentheses.
* @param id the pattern the parse
* @param dir the direction.
* @param canonID OUTPUT parameter that receives the canonical ID,
* consisting of canonical IDs for all elements, as returned by
* parseSingleID(), separated by semicolons. Previous contents
* are discarded.
* @param list OUTPUT parameter that receives a list of SingleID
* objects representing the parsed IDs. Previous contents are
* discarded.
* @param globalFilter OUTPUT parameter that receives a pointer to
* a newly created global filter for this ID in this direction, or
* null if there is none.
* @return true if the parse succeeds, that is, if the entire
* id is consumed without syntax error.
*/
static UBool parseCompoundID(const UnicodeString& id, int32_t dir,
UnicodeString& canonID,
UVector& list,
UnicodeSet*& globalFilter);
/**
* Convert the elements of the 'list' vector, which are SingleID
* objects, into actual Transliterator objects. In the course of
* this, some (or all) entries may be removed. If all entries
* are removed, the Null transliterator will be added.
*
* Delete entries with empty basicIDs; these are generated by
* elements like "(A)" in the forward direction, or "A()" in
* the reverse. THIS MAY RESULT IN AN EMPTY VECTOR. Convert
* SingleID entries to actual transliterators.
*
* Also, optionally, insert the given transliterator at the given
* position. This effectively happens before anything else.
*
* @param list vector of SingleID objects. On exit, vector
* of one or more Transliterators.
* @param insert Transliterator to insert, or null if none.
* @param insertIndex index from 0..list.size()-1, at which
* to place 'insert', or -1 if none.
* @return new value of insertIndex. The index will shift if
* there are empty items, like "(Lower)", with indices less than
* insertIndex.
*/
static int32_t instantiateList(UVector& list,
Transliterator* insert,
int32_t insertIndex,
UErrorCode& ec);
/**
* Parse an ID into pieces. Take IDs of the form T, T/V, S-T,
* S-T/V, or S/V-T. If the source is missing, return a source of
* ANY.
* @param id the id string, in any of several forms
* @return an array of 4 strings: source, target, variant, and
* isSourcePresent. If the source is not present, ANY will be
* given as the source, and isSourcePresent will be null. Otherwise
* isSourcePresent will be non-null. The target may be empty if the
* id is not well-formed. The variant may be empty.
*/
static void IDtoSTV(const UnicodeString& id,
UnicodeString& source,
UnicodeString& target,
UnicodeString& variant,
UBool& isSourcePresent);
/**
* Register two targets as being inverses of one another. For
* example, calling registerSpecialInverse("NFC", "NFD", true) causes
* Transliterator to form the following inverse relationships:
*
* NFC => NFD
* Any-NFC => Any-NFD
* NFD => NFC
* Any-NFD => Any-NFC
*
* (Without the special inverse registration, the inverse of NFC
* would be NFC-Any.) Note that NFD is shorthand for Any-NFD, but
* that the presence or absence of "Any-" is preserved.
*
* The relationship is symmetrical; registering (a, b) is
* equivalent to registering (b, a).
*
*
The relevant IDs must still be registered separately as
* factories or classes.
*
*
Only the targets are specified. Special inverses always
* have the form Any-Target1 <=> Any-Target2. The target should
* have canonical casing (the casing desired to be produced when
* an inverse is formed) and should contain no whitespace or other
* extraneous characters.
*
* @param target the target against which to register the inverse
* @param inverseTarget the inverse of target, that is
* Any-target.getInverse() => Any-inverseTarget
* @param bidirectional if true, register the reverse relation
* as well, that is, Any-inverseTarget.getInverse() => Any-target
*/
static void registerSpecialInverse(const UnicodeString& target,
const UnicodeString& inverseTarget,
UBool bidirectional);
/**
* Free static memory.
*/
static void cleanup();
private:
//----------------------------------------------------------------
// Private implementation
//----------------------------------------------------------------
/**
* Parse an ID into component pieces. Take IDs of the form T,
* T/V, S-T, S-T/V, or S/V-T. If the source is missing, return a
* source of ANY.
* @param id the id string, in any of several forms
* @param pos INPUT-OUTPUT parameter. On input, pos[0] is the
* offset of the first character to parse in id. On output,
* pos[0] is the offset after the last parsed character. If the
* parse failed, pos[0] will be unchanged.
* @param allowFilter if true, a UnicodeSet pattern is allowed
* at any location between specs or delimiters, and is returned
* as the fifth string in the array.
* @return a Specs object, or null if the parse failed. If
* neither source nor target was seen in the parsed id, then the
* parse fails. If allowFilter is true, then the parsed filter
* pattern is returned in the Specs object, otherwise the returned
* filter reference is null. If the parse fails for any reason
* null is returned.
*/
static Specs* parseFilterID(const UnicodeString& id, int32_t& pos,
UBool allowFilter);
/**
* Givens a Spec object, convert it to a SingleID object. The
* Spec object is a more unprocessed parse result. The SingleID
* object contains information about canonical and basic IDs.
* @return a SingleID; never returns null. Returned object always
* has 'filter' field of null.
*/
static SingleID* specsToID(const Specs* specs, int32_t dir);
/**
* Given a Specs object, return a SingleID representing the
* special inverse of that ID. If there is no special inverse
* then return null.
* @return a SingleID or null. Returned object always has
* 'filter' field of null.
*/
static SingleID* specsToSpecialInverse(const Specs& specs);
/**
* Glue method to get around access problems in C++.
*/
static Transliterator* createBasicInstance(const UnicodeString& id,
const UnicodeString* canonID);
/**
* Initialize static memory.
*/
static void init();
friend class SingleID;
};
U_NAMESPACE_END
#endif