xref: /aosp_15_r20/external/icu/libicu/ndk_headers/unicode/utrans.h (revision 0e209d3975ff4a8c132096b14b0e9364a753506e)

// © 2016 and later: Unicode, Inc. and others.
// License & terms of use: http://www.unicode.org/copyright.html
/*
*******************************************************************************
*   Copyright (C) 1997-2011,2014-2015 International Business Machines
*   Corporation and others.  All Rights Reserved.
*******************************************************************************
*   Date        Name        Description
*   06/21/00    aliu        Creation.
*******************************************************************************
*/

#ifndef UTRANS_H
#define UTRANS_H

#include "unicode/utypes.h"

#if !UCONFIG_NO_TRANSLITERATION

#include "unicode/urep.h"
#include "unicode/parseerr.h"
#include "unicode/uenum.h"

#if U_SHOW_CPLUSPLUS_API
#include "unicode/localpointer.h"
#endif   // U_SHOW_CPLUSPLUS_API

/********************************************************************
 * General Notes
 ********************************************************************
 */
/**
 * @addtogroup icu4c ICU4C
 * @{
 * \file
 * \brief C API: Transliterator
 *
 * <h2> Transliteration </h2>
 * The data structures and functions described in this header provide
 * transliteration services.  Transliteration services are implemented
 * as C++ classes.  The comments and documentation in this header
 * assume the reader is familiar with the C++ headers translit.h and
 * associated documentation.
 *
 * A significant but incomplete subset of the C++ transliteration
 * services are available to C code through this header.  In order to
 * access more complex transliteration services, refer to the C++
 * headers and documentation.
 *
 * There are two sets of functions for working with transliterator IDs:
 *
 * An old, deprecated set uses char * IDs, which works for true and pure
 * identifiers that these APIs were designed for,
 * for example "Cyrillic-Latin".
 * It does not work when the ID contains filters ("[:Script=Cyrl:]")
 * or even a complete set of rules because then the ID string contains more
 * than just "invariant" characters (see utypes.h).
 *
 * A new set of functions replaces the old ones and uses UChar * IDs,
 * paralleling the UnicodeString IDs in the C++ API. (New in ICU 2.8.)
 */

/********************************************************************
 * Data Structures
 ********************************************************************/

/**
 * An opaque transliterator for use in C.  Open with utrans_openxxx()
 * and close with utrans_close() when done.  Equivalent to the C++ class
 * Transliterator and its subclasses.
 * @see Transliterator
 * \xrefitem stable "Stable" "Stable List" ICU 2.0
 */
typedef void* UTransliterator;

/**
 * Direction constant indicating the direction in a transliterator,
 * e.g., the forward or reverse rules of a RuleBasedTransliterator.
 * Specified when a transliterator is opened.  An "A-B" transliterator
 * transliterates A to B when operating in the forward direction, and
 * B to A when operating in the reverse direction.
 * \xrefitem stable "Stable" "Stable List" ICU 2.0
 */
typedef enum UTransDirection {

    /**
     * UTRANS_FORWARD means from &lt;source&gt; to &lt;target&gt; for a
     * transliterator with ID &lt;source&gt;-&lt;target&gt;.  For a transliterator
     * opened using a rule, it means forward direction rules, e.g.,
     * "A > B".
     */
    UTRANS_FORWARD,

    /**
     * UTRANS_REVERSE means from &lt;target&gt; to &lt;source&gt; for a
     * transliterator with ID &lt;source&gt;-&lt;target&gt;.  For a transliterator
     * opened using a rule, it means reverse direction rules, e.g.,
     * "A < B".
     */
    UTRANS_REVERSE

} UTransDirection;

/**
 * Position structure for utrans_transIncremental() incremental
 * transliteration.  This structure defines two substrings of the text
 * being transliterated.  The first region, [contextStart,
 * contextLimit), defines what characters the transliterator will read
 * as context.  The second region, [start, limit), defines what
 * characters will actually be transliterated.  The second region
 * should be a subset of the first.
 *
 * <p>After a transliteration operation, some of the indices in this
 * structure will be modified.  See the field descriptions for
 * details.
 *
 * <p>contextStart <= start <= limit <= contextLimit
 *
 * <p>Note: All index values in this structure must be at code point
 * boundaries.  That is, none of them may occur between two code units
 * of a surrogate pair.  If any index does split a surrogate pair,
 * results are unspecified.
 *
 * \xrefitem stable "Stable" "Stable List" ICU 2.0
 */
typedef struct UTransPosition {

    /**
     * Beginning index, inclusive, of the context to be considered for
     * a transliteration operation.  The transliterator will ignore
     * anything before this index.  INPUT/OUTPUT parameter: This parameter
     * is updated by a transliteration operation to reflect the maximum
     * amount of antecontext needed by a transliterator.
     * \xrefitem stable "Stable" "Stable List" ICU 2.4
     */
    int32_t contextStart;

    /**
     * Ending index, exclusive, of the context to be considered for a
     * transliteration operation.  The transliterator will ignore
     * anything at or after this index.  INPUT/OUTPUT parameter: This
     * parameter is updated to reflect changes in the length of the
     * text, but points to the same logical position in the text.
     * \xrefitem stable "Stable" "Stable List" ICU 2.4
     */
    int32_t contextLimit;

    /**
     * Beginning index, inclusive, of the text to be transliterated.
     * INPUT/OUTPUT parameter: This parameter is advanced past
     * characters that have already been transliterated by a
     * transliteration operation.
     * \xrefitem stable "Stable" "Stable List" ICU 2.4
     */
    int32_t start;

    /**
     * Ending index, exclusive, of the text to be transliterated.
     * INPUT/OUTPUT parameter: This parameter is updated to reflect
     * changes in the length of the text, but points to the same
     * logical position in the text.
     * \xrefitem stable "Stable" "Stable List" ICU 2.4
     */
    int32_t limit;

} UTransPosition;

/********************************************************************
 * General API
 ********************************************************************/

/**
 * Open a custom transliterator, given a custom rules string
 * OR
 * a system transliterator, given its ID.
 * Any non-NULL result from this function should later be closed with
 * utrans_close().
 *
 * @param id a valid transliterator ID
 * @param idLength the length of the ID string, or -1 if NUL-terminated
 * @param dir the desired direction
 * @param rules the transliterator rules.  See the C++ header rbt.h for
 *              rules syntax. If NULL then a system transliterator matching
 *              the ID is returned.
 * @param rulesLength the length of the rules, or -1 if the rules
 *                    are NUL-terminated.
 * @param parseError a pointer to a UParseError struct to receive the details
 *                   of any parsing errors. This parameter may be NULL if no
 *                   parsing error details are desired.
 * @param pErrorCode a pointer to the UErrorCode
 * @return a transliterator pointer that may be passed to other
 *         utrans_xxx() functions, or NULL if the open call fails.
 * \xrefitem stable "Stable" "Stable List" ICU 2.8
 */
U_CAPI UTransliterator* U_EXPORT2
utrans_openU(const UChar *id,
             int32_t idLength,
             UTransDirection dir,
             const UChar *rules,
             int32_t rulesLength,
             UParseError *parseError,
             UErrorCode *pErrorCode) __INTRODUCED_IN(__ANDROID_API_T__);



/**
 * Open an inverse of an existing transliterator.  For this to work,
 * the inverse must be registered with the system.  For example, if
 * the Transliterator "A-B" is opened, and then its inverse is opened,
 * the result is the Transliterator "B-A", if such a transliterator is
 * registered with the system.  Otherwise the result is NULL and a
 * failing UErrorCode is set.  Any non-NULL result from this function
 * should later be closed with utrans_close().
 *
 * @param trans the transliterator to open the inverse of.
 * @param status a pointer to the UErrorCode
 * @return a pointer to a newly-opened transliterator that is the
 * inverse of trans, or NULL if the open call fails.
 * \xrefitem stable "Stable" "Stable List" ICU 2.0
 */
U_CAPI UTransliterator* U_EXPORT2
utrans_openInverse(const UTransliterator* trans,
                   UErrorCode* status) __INTRODUCED_IN(__ANDROID_API_T__);



/**
 * Create a copy of a transliterator.  Any non-NULL result from this
 * function should later be closed with utrans_close().
 *
 * @param trans the transliterator to be copied.
 * @param status a pointer to the UErrorCode
 * @return a transliterator pointer that may be passed to other
 * utrans_xxx() functions, or NULL if the clone call fails.
 * \xrefitem stable "Stable" "Stable List" ICU 2.0
 */
U_CAPI UTransliterator* U_EXPORT2
utrans_clone(const UTransliterator* trans,
             UErrorCode* status) __INTRODUCED_IN(__ANDROID_API_T__);



/**
 * Close a transliterator.  Any non-NULL pointer returned by
 * utrans_openXxx() or utrans_clone() should eventually be closed.
 * @param trans the transliterator to be closed.
 * \xrefitem stable "Stable" "Stable List" ICU 2.0
 */
U_CAPI void U_EXPORT2
utrans_close(UTransliterator* trans) __INTRODUCED_IN(__ANDROID_API_T__);



#if U_SHOW_CPLUSPLUS_API

U_NAMESPACE_BEGIN

/**
 * \class LocalUTransliteratorPointer
 * "Smart pointer" class, closes a UTransliterator via utrans_close().
 * For most methods see the LocalPointerBase base class.
 *
 * @see LocalPointerBase
 * @see LocalPointer
 * \xrefitem stable "Stable" "Stable List" ICU 4.4
 */
U_DEFINE_LOCAL_OPEN_POINTER(LocalUTransliteratorPointer, UTransliterator, utrans_close);

U_NAMESPACE_END

#endif







/**
 * Set the filter used by a transliterator.  A filter can be used to
 * make the transliterator pass certain characters through untouched.
 * The filter is expressed using a UnicodeSet pattern.  If the
 * filterPattern is NULL or the empty string, then the transliterator
 * will be reset to use no filter.
 *
 * @param trans the transliterator
 * @param filterPattern a pattern string, in the form accepted by
 * UnicodeSet, specifying which characters to apply the
 * transliteration to.  May be NULL or the empty string to indicate no
 * filter.
 * @param filterPatternLen the length of filterPattern, or -1 if
 * filterPattern is zero-terminated
 * @param status a pointer to the UErrorCode
 * @see UnicodeSet
 * \xrefitem stable "Stable" "Stable List" ICU 2.0
 */
U_CAPI void U_EXPORT2
utrans_setFilter(UTransliterator* trans,
                 const UChar* filterPattern,
                 int32_t filterPatternLen,
                 UErrorCode* status) __INTRODUCED_IN(__ANDROID_API_T__);





/**
 * Return a UEnumeration for the available transliterators.
 *
 * @param pErrorCode Pointer to the UErrorCode in/out parameter.
 * @return UEnumeration for the available transliterators.
 *         Close with uenum_close().
 *
 * \xrefitem stable "Stable" "Stable List" ICU 2.8
 */
U_CAPI UEnumeration * U_EXPORT2
utrans_openIDs(UErrorCode *pErrorCode) __INTRODUCED_IN(__ANDROID_API_T__);



/********************************************************************
 * Transliteration API
 ********************************************************************/

/**
 * Transliterate a segment of a UReplaceable string.  The string is
 * passed in as a UReplaceable pointer rep and a UReplaceableCallbacks
 * function pointer struct repFunc.  Functions in the repFunc struct
 * will be called in order to modify the rep string.
 *
 * @param trans the transliterator
 * @param rep a pointer to the string.  This will be passed to the
 * repFunc functions.
 * @param repFunc a set of function pointers that will be used to
 * modify the string pointed to by rep.
 * @param start the beginning index, inclusive; <code>0 <= start <=
 * limit</code>.
 * @param limit pointer to the ending index, exclusive; <code>start <=
 * limit <= repFunc->length(rep)</code>.  Upon return, *limit will
 * contain the new limit index.  The text previously occupying
 * <code>[start, limit)</code> has been transliterated, possibly to a
 * string of a different length, at <code>[start,
 * </code><em>new-limit</em><code>)</code>, where <em>new-limit</em>
 * is the return value.
 * @param status a pointer to the UErrorCode
 * \xrefitem stable "Stable" "Stable List" ICU 2.0
 */
U_CAPI void U_EXPORT2
utrans_trans(const UTransliterator* trans,
             UReplaceable* rep,
             const UReplaceableCallbacks* repFunc,
             int32_t start,
             int32_t* limit,
             UErrorCode* status) __INTRODUCED_IN(__ANDROID_API_T__);



/**
 * Transliterate the portion of the UReplaceable text buffer that can
 * be transliterated unambiguously.  This method is typically called
 * after new text has been inserted, e.g. as a result of a keyboard
 * event.  The transliterator will try to transliterate characters of
 * <code>rep</code> between <code>index.cursor</code> and
 * <code>index.limit</code>.  Characters before
 * <code>index.cursor</code> will not be changed.
 *
 * <p>Upon return, values in <code>index</code> will be updated.
 * <code>index.start</code> will be advanced to the first
 * character that future calls to this method will read.
 * <code>index.cursor</code> and <code>index.limit</code> will
 * be adjusted to delimit the range of text that future calls to
 * this method may change.
 *
 * <p>Typical usage of this method begins with an initial call
 * with <code>index.start</code> and <code>index.limit</code>
 * set to indicate the portion of <code>text</code> to be
 * transliterated, and <code>index.cursor == index.start</code>.
 * Thereafter, <code>index</code> can be used without
 * modification in future calls, provided that all changes to
 * <code>text</code> are made via this method.
 *
 * <p>This method assumes that future calls may be made that will
 * insert new text into the buffer.  As a result, it only performs
 * unambiguous transliterations.  After the last call to this method,
 * there may be untransliterated text that is waiting for more input
 * to resolve an ambiguity.  In order to perform these pending
 * transliterations, clients should call utrans_trans() with a start
 * of index.start and a limit of index.end after the last call to this
 * method has been made.
 *
 * @param trans the transliterator
 * @param rep a pointer to the string.  This will be passed to the
 * repFunc functions.
 * @param repFunc a set of function pointers that will be used to
 * modify the string pointed to by rep.
 * @param pos a struct containing the start and limit indices of the
 * text to be read and the text to be transliterated
 * @param status a pointer to the UErrorCode
 * \xrefitem stable "Stable" "Stable List" ICU 2.0
 */
U_CAPI void U_EXPORT2
utrans_transIncremental(const UTransliterator* trans,
                        UReplaceable* rep,
                        const UReplaceableCallbacks* repFunc,
                        UTransPosition* pos,
                        UErrorCode* status) __INTRODUCED_IN(__ANDROID_API_T__);



/**
 * Transliterate a segment of a UChar* string.  The string is passed
 * in in a UChar* buffer.  The string is modified in place.  If the
 * result is longer than textCapacity, it is truncated.  The actual
 * length of the result is returned in *textLength, if textLength is
 * non-NULL. *textLength may be greater than textCapacity, but only
 * textCapacity UChars will be written to *text, including the zero
 * terminator.
 *
 * @param trans the transliterator
 * @param text a pointer to a buffer containing the text to be
 * transliterated on input and the result text on output.
 * @param textLength a pointer to the length of the string in text.
 * If the length is -1 then the string is assumed to be
 * zero-terminated.  Upon return, the new length is stored in
 * *textLength.  If textLength is NULL then the string is assumed to
 * be zero-terminated.
 * @param textCapacity the length of the text buffer
 * @param start the beginning index, inclusive; <code>0 <= start <=
 * limit</code>.
 * @param limit pointer to the ending index, exclusive; <code>start <=
 * limit <= repFunc->length(rep)</code>.  Upon return, *limit will
 * contain the new limit index.  The text previously occupying
 * <code>[start, limit)</code> has been transliterated, possibly to a
 * string of a different length, at <code>[start,
 * </code><em>new-limit</em><code>)</code>, where <em>new-limit</em>
 * is the return value.
 * @param status a pointer to the UErrorCode
 * \xrefitem stable "Stable" "Stable List" ICU 2.0
 */
U_CAPI void U_EXPORT2
utrans_transUChars(const UTransliterator* trans,
                   UChar* text,
                   int32_t* textLength,
                   int32_t textCapacity,
                   int32_t start,
                   int32_t* limit,
                   UErrorCode* status) __INTRODUCED_IN(__ANDROID_API_T__);



/**
 * Transliterate the portion of the UChar* text buffer that can be
 * transliterated unambiguously.  See utrans_transIncremental().  The
 * string is passed in in a UChar* buffer.  The string is modified in
 * place.  If the result is longer than textCapacity, it is truncated.
 * The actual length of the result is returned in *textLength, if
 * textLength is non-NULL. *textLength may be greater than
 * textCapacity, but only textCapacity UChars will be written to
 * *text, including the zero terminator.  See utrans_transIncremental()
 * for usage details.
 *
 * @param trans the transliterator
 * @param text a pointer to a buffer containing the text to be
 * transliterated on input and the result text on output.
 * @param textLength a pointer to the length of the string in text.
 * If the length is -1 then the string is assumed to be
 * zero-terminated.  Upon return, the new length is stored in
 * *textLength.  If textLength is NULL then the string is assumed to
 * be zero-terminated.
 * @param textCapacity the length of the text buffer
 * @param pos a struct containing the start and limit indices of the
 * text to be read and the text to be transliterated
 * @param status a pointer to the UErrorCode
 * @see utrans_transIncremental
 * \xrefitem stable "Stable" "Stable List" ICU 2.0
 */
U_CAPI void U_EXPORT2
utrans_transIncrementalUChars(const UTransliterator* trans,
                              UChar* text,
                              int32_t* textLength,
                              int32_t textCapacity,
                              UTransPosition* pos,
                              UErrorCode* status) __INTRODUCED_IN(__ANDROID_API_T__);



/**
 * Create a rule string that can be passed to utrans_openU to recreate this
 * transliterator.
 *
 * @param trans     The transliterator
 * @param escapeUnprintable if true then convert unprintable characters to their
 *                  hex escape representations, \\uxxxx or \\Uxxxxxxxx.
 *                  Unprintable characters are those other than
 *                  U+000A, U+0020..U+007E.
 * @param result    A pointer to a buffer to receive the rules.
 * @param resultLength The maximum size of result.
 * @param status    A pointer to the UErrorCode. In case of error status, the
 *                  contents of result are undefined.
 * @return int32_t   The length of the rule string (may be greater than resultLength,
 *                  in which case an error is returned).
 * \xrefitem stable "Stable" "Stable List" ICU 53
 */
U_CAPI int32_t U_EXPORT2
utrans_toRules(     const UTransliterator* trans,
                    UBool escapeUnprintable,
                    UChar* result, int32_t resultLength,
                    UErrorCode* status) __INTRODUCED_IN(__ANDROID_API_T__);





/* deprecated API ----------------------------------------------------------- */

#ifndef U_HIDE_DEPRECATED_API

/* see utrans.h documentation for why these functions are deprecated */









#endif  /* U_HIDE_DEPRECATED_API */

#endif /* #if !UCONFIG_NO_TRANSLITERATION */

#endif

/** @} */ // addtogroup