1// © 2016 and later: Unicode, Inc. and others.
2// License & terms of use: http://www.unicode.org/copyright.html
3/*
4*******************************************************************************
5*
6* Copyright (C) 2004-2012, International Business Machines
7* Corporation and others. All Rights Reserved.
8*
9*******************************************************************************
10* file name: utext.h
11* encoding: UTF-8
12* tab size: 8 (not used)
13* indentation:4
14*
15* created on: 2004oct06
16* created by: Markus W. Scherer
17*/
18
19#ifndef __UTEXT_H__
20#define __UTEXT_H__
21
22/**
23 * \file
24 * \brief C API: Abstract Unicode Text API
25 *
26 * The Text Access API provides a means to allow text that is stored in alternative
27 * formats to work with ICU services. ICU normally operates on text that is
28 * stored in UTF-16 format, in (UChar *) arrays for the C APIs or as type
29 * UnicodeString for C++ APIs.
30 *
31 * ICU Text Access allows other formats, such as UTF-8 or non-contiguous
32 * UTF-16 strings, to be placed in a UText wrapper and then passed to ICU services.
33 *
34 * There are three general classes of usage for UText:
35 *
36 * Application Level Use. This is the simplest usage - applications would
37 * use one of the utext_open() functions on their input text, and pass
38 * the resulting UText to the desired ICU service.
39 *
40 * Second is usage in ICU Services, such as break iteration, that will need to
41 * operate on input presented to them as a UText. These implementations
42 * will need to use the iteration and related UText functions to gain
43 * access to the actual text.
44 *
45 * The third class of UText users are "text providers." These are the
46 * UText implementations for the various text storage formats. An application
47 * or system with a unique text storage format can implement a set of
48 * UText provider functions for that format, which will then allow
49 * ICU services to operate on that format.
50 *
51 *
52 * <em>Iterating over text</em>
53 *
54 * Here is sample code for a forward iteration over the contents of a UText
55 *
56 * \code
57 * UChar32 c;
58 * UText *ut = whatever();
59 *
60 * for (c=utext_next32From(ut, 0); c>=0; c=utext_next32(ut)) {
61 * // do whatever with the codepoint c here.
62 * }
63 * \endcode
64 *
65 * And here is similar code to iterate in the reverse direction, from the end
66 * of the text towards the beginning.
67 *
68 * \code
69 * UChar32 c;
70 * UText *ut = whatever();
71 * int textLength = utext_nativeLength(ut);
72 * for (c=utext_previous32From(ut, textLength); c>=0; c=utext_previous32(ut)) {
73 * // do whatever with the codepoint c here.
74 * }
75 * \endcode
76 *
77 * <em>Characters and Indexing</em>
78 *
79 * Indexing into text by UText functions is nearly always in terms of the native
80 * indexing of the underlying text storage. The storage format could be UTF-8
81 * or UTF-32, for example. When coding to the UText access API, no assumptions
82 * can be made regarding the size of characters, or how far an index
83 * may move when iterating between characters.
84 *
85 * All indices supplied to UText functions are pinned to the length of the
86 * text. An out-of-bounds index is not considered to be an error, but is
87 * adjusted to be in the range 0 <= index <= length of input text.
88 *
89 *
90 * When an index position is returned from a UText function, it will be
91 * a native index to the underlying text. In the case of multi-unit characters,
92 * it will always refer to the first position of the character,
93 * never to the interior. This is essentially the same thing as saying that
94 * a returned index will always point to a boundary between characters.
95 *
96 * When a native index is supplied to a UText function, all indices that
97 * refer to any part of a multi-unit character representation are considered
98 * to be equivalent. In the case of multi-unit characters, an incoming index
99 * will be logically normalized to refer to the start of the character.
100 *
101 * It is possible to test whether a native index is on a code point boundary
102 * by doing a utext_setNativeIndex() followed by a utext_getNativeIndex().
103 * If the index is returned unchanged, it was on a code point boundary. If
104 * an adjusted index is returned, the original index referred to the
105 * interior of a character.
106 *
107 * <em>Conventions for calling UText functions</em>
108 *
109 * Most UText access functions have as their first parameter a (UText *) pointer,
110 * which specifies the UText to be used. Unless otherwise noted, the
111 * pointer must refer to a valid, open UText. Attempting to
112 * use a closed UText or passing a NULL pointer is a programming error and
113 * will produce undefined results or NULL pointer exceptions.
114 *
115 * The UText_Open family of functions can either open an existing (closed)
116 * UText, or heap allocate a new UText. Here is sample code for creating
117 * a stack-allocated UText.
118 *
119 * \code
120 * char *s = whatever(); // A utf-8 string
121 * U_ErrorCode status = U_ZERO_ERROR;
122 * UText ut = UTEXT_INITIALIZER;
123 * utext_openUTF8(ut, s, -1, &status);
124 * if (U_FAILURE(status)) {
125 * // error handling
126 * } else {
127 * // work with the UText
128 * }
129 * \endcode
130 *
131 * Any existing UText passed to an open function _must_ have been initialized,
132 * either by the UTEXT_INITIALIZER, or by having been originally heap-allocated
133 * by an open function. Passing NULL will cause the open function to
134 * heap-allocate and fully initialize a new UText.
135 *
136 */
137
138
139
140#include "unicode/utypes.h"
141#include "unicode/uchar.h"
142#if U_SHOW_CPLUSPLUS_API
143#include "unicode/localpointer.h"
144#include "unicode/rep.h"
145#include "unicode/unistr.h"
146#include "unicode/chariter.h"
147#endif
148
149
150U_CDECL_BEGIN
151
152struct UText;
153typedef struct UText UText; /**< C typedef for struct UText. @stable ICU 3.6 */
154
155
156/***************************************************************************************
157 *
158 * C Functions for creating UText wrappers around various kinds of text strings.
159 *
160 ****************************************************************************************/
161
162
163/**
164 * Close function for UText instances.
165 * Cleans up, releases any resources being held by an open UText.
166 * <p>
167 * If the UText was originally allocated by one of the utext_open functions,
168 * the storage associated with the utext will also be freed.
169 * If the UText storage originated with the application, as it would with
170 * a local or static instance, the storage will not be deleted.
171 *
172 * An open UText can be reset to refer to new string by using one of the utext_open()
173 * functions without first closing the UText.
174 *
175 * @param ut The UText to be closed.
176 * @return NULL if the UText struct was deleted by the close. If the UText struct
177 * was originally provided by the caller to the open function, it is
178 * returned by this function, and may be safely used again in
179 * a subsequent utext_open.
180 *
181 * @stable ICU 3.4
182 */
183U_STABLE UText * U_EXPORT2
184utext_close(UText *ut);
185
186#if U_SHOW_CPLUSPLUS_API
187
188U_NAMESPACE_BEGIN
189
190/**
191 * \class LocalUTextPointer
192 * "Smart pointer" class, closes a UText via utext_close().
193 * For most methods see the LocalPointerBase base class.
194 *
195 * @see LocalPointerBase
196 * @see LocalPointer
197 * @stable ICU 4.4
198 */
199U_DEFINE_LOCAL_OPEN_POINTER(LocalUTextPointer, UText, utext_close);
200
201U_NAMESPACE_END
202
203#endif
204
205/**
206 * Open a read-only UText implementation for UTF-8 strings.
207 *
208 * \htmlonly
209 * Any invalid UTF-8 in the input will be handled in this way:
210 * a sequence of bytes that has the form of a truncated, but otherwise valid,
211 * UTF-8 sequence will be replaced by a single unicode replacement character, \uFFFD.
212 * Any other illegal bytes will each be replaced by a \uFFFD.
213 * \endhtmlonly
214 *
215 * @param ut Pointer to a UText struct. If NULL, a new UText will be created.
216 * If non-NULL, must refer to an initialized UText struct, which will then
217 * be reset to reference the specified UTF-8 string.
218 * @param s A UTF-8 string. Must not be NULL.
219 * @param length The length of the UTF-8 string in bytes, or -1 if the string is
220 * zero terminated.
221 * @param status Errors are returned here.
222 * @return A pointer to the UText. If a pre-allocated UText was provided, it
223 * will always be used and returned.
224 * @stable ICU 3.4
225 */
226U_STABLE UText * U_EXPORT2
227utext_openUTF8(UText *ut, const char *s, int64_t length, UErrorCode *status);
228
229
230/**
231 * Open a read-only UText for UChar * string.
232 *
233 * @param ut Pointer to a UText struct. If NULL, a new UText will be created.
234 * If non-NULL, must refer to an initialized UText struct, which will then
235 * be reset to reference the specified UChar string.
236 * @param s A UChar (UTF-16) string
237 * @param length The number of UChars in the input string, or -1 if the string is
238 * zero terminated.
239 * @param status Errors are returned here.
240 * @return A pointer to the UText. If a pre-allocated UText was provided, it
241 * will always be used and returned.
242 * @stable ICU 3.4
243 */
244U_STABLE UText * U_EXPORT2
245utext_openUChars(UText *ut, const UChar *s, int64_t length, UErrorCode *status);
246
247
248#if U_SHOW_CPLUSPLUS_API
249/**
250 * Open a writable UText for a non-const UnicodeString.
251 *
252 * @param ut Pointer to a UText struct. If NULL, a new UText will be created.
253 * If non-NULL, must refer to an initialized UText struct, which will then
254 * be reset to reference the specified input string.
255 * @param s A UnicodeString.
256 * @param status Errors are returned here.
257 * @return Pointer to the UText. If a UText was supplied as input, this
258 * will always be used and returned.
259 * @stable ICU 3.4
260 */
261U_STABLE UText * U_EXPORT2
262utext_openUnicodeString(UText *ut, icu::UnicodeString *s, UErrorCode *status);
263
264
265/**
266 * Open a UText for a const UnicodeString. The resulting UText will not be writable.
267 *
268 * @param ut Pointer to a UText struct. If NULL, a new UText will be created.
269 * If non-NULL, must refer to an initialized UText struct, which will then
270 * be reset to reference the specified input string.
271 * @param s A const UnicodeString to be wrapped.
272 * @param status Errors are returned here.
273 * @return Pointer to the UText. If a UText was supplied as input, this
274 * will always be used and returned.
275 * @stable ICU 3.4
276 */
277U_STABLE UText * U_EXPORT2
278utext_openConstUnicodeString(UText *ut, const icu::UnicodeString *s, UErrorCode *status);
279
280
281/**
282 * Open a writable UText implementation for an ICU Replaceable object.
283 * @param ut Pointer to a UText struct. If NULL, a new UText will be created.
284 * If non-NULL, must refer to an already existing UText, which will then
285 * be reset to reference the specified replaceable text.
286 * @param rep A Replaceable text object.
287 * @param status Errors are returned here.
288 * @return Pointer to the UText. If a UText was supplied as input, this
289 * will always be used and returned.
290 * @see Replaceable
291 * @stable ICU 3.4
292 */
293U_STABLE UText * U_EXPORT2
294utext_openReplaceable(UText *ut, icu::Replaceable *rep, UErrorCode *status);
295
296/**
297 * Open a UText implementation over an ICU CharacterIterator.
298 * @param ut Pointer to a UText struct. If NULL, a new UText will be created.
299 * If non-NULL, must refer to an already existing UText, which will then
300 * be reset to reference the specified replaceable text.
301 * @param ci A Character Iterator.
302 * @param status Errors are returned here.
303 * @return Pointer to the UText. If a UText was supplied as input, this
304 * will always be used and returned.
305 * @see Replaceable
306 * @stable ICU 3.4
307 */
308U_STABLE UText * U_EXPORT2
309utext_openCharacterIterator(UText *ut, icu::CharacterIterator *ci, UErrorCode *status);
310
311#endif
312
313
314/**
315 * Clone a UText. This is much like opening a UText where the source text is itself
316 * another UText.
317 *
318 * A deep clone will copy both the UText data structures and the underlying text.
319 * The original and cloned UText will operate completely independently; modifications
320 * made to the text in one will not affect the other. Text providers are not
321 * required to support deep clones. The user of clone() must check the status return
322 * and be prepared to handle failures.
323 *
324 * The standard UText implementations for UTF8, UChar *, UnicodeString and
325 * Replaceable all support deep cloning.
326 *
327 * The UText returned from a deep clone will be writable, assuming that the text
328 * provider is able to support writing, even if the source UText had been made
329 * non-writable by means of UText_freeze().
330 *
331 * A shallow clone replicates only the UText data structures; it does not make
332 * a copy of the underlying text. Shallow clones can be used as an efficient way to
333 * have multiple iterators active in a single text string that is not being
334 * modified.
335 *
336 * A shallow clone operation will not fail, barring truly exceptional conditions such
337 * as memory allocation failures.
338 *
339 * Shallow UText clones should be avoided if the UText functions that modify the
340 * text are expected to be used, either on the original or the cloned UText.
341 * Any such modifications can cause unpredictable behavior. Read Only
342 * shallow clones provide some protection against errors of this type by
343 * disabling text modification via the cloned UText.
344 *
345 * A shallow clone made with the readOnly parameter == FALSE will preserve the
346 * utext_isWritable() state of the source object. Note, however, that
347 * write operations must be avoided while more than one UText exists that refer
348 * to the same underlying text.
349 *
350 * A UText and its clone may be safely concurrently accessed by separate threads.
351 * This is true for read access only with shallow clones, and for both read and
352 * write access with deep clones.
353 * It is the responsibility of the Text Provider to ensure that this thread safety
354 * constraint is met.
355 *
356 * @param dest A UText struct to be filled in with the result of the clone operation,
357 * or NULL if the clone function should heap-allocate a new UText struct.
358 * If non-NULL, must refer to an already existing UText, which will then
359 * be reset to become the clone.
360 * @param src The UText to be cloned.
361 * @param deep TRUE to request a deep clone, FALSE for a shallow clone.
362 * @param readOnly TRUE to request that the cloned UText have read only access to the
363 * underlying text.
364
365 * @param status Errors are returned here. For deep clones, U_UNSUPPORTED_ERROR
366 * will be returned if the text provider is unable to clone the
367 * original text.
368 * @return The newly created clone, or NULL if the clone operation failed.
369 * @stable ICU 3.4
370 */
371U_STABLE UText * U_EXPORT2
372utext_clone(UText *dest, const UText *src, UBool deep, UBool readOnly, UErrorCode *status);
373
374
375/**
376 * Compare two UText objects for equality.
377 * UTexts are equal if they are iterating over the same text, and
378 * have the same iteration position within the text.
379 * If either or both of the parameters are NULL, the comparison is FALSE.
380 *
381 * @param a The first of the two UTexts to compare.
382 * @param b The other UText to be compared.
383 * @return TRUE if the two UTexts are equal.
384 * @stable ICU 3.6
385 */
386U_STABLE UBool U_EXPORT2
387utext_equals(const UText *a, const UText *b);
388
389
390/*****************************************************************************
391 *
392 * Functions to work with the text represented by a UText wrapper
393 *
394 *****************************************************************************/
395
396/**
397 * Get the length of the text. Depending on the characteristics
398 * of the underlying text representation, this may be expensive.
399 * @see utext_isLengthExpensive()
400 *
401 *
402 * @param ut the text to be accessed.
403 * @return the length of the text, expressed in native units.
404 *
405 * @stable ICU 3.4
406 */
407U_STABLE int64_t U_EXPORT2
408utext_nativeLength(UText *ut);
409
410/**
411 * Return TRUE if calculating the length of the text could be expensive.
412 * Finding the length of NUL terminated strings is considered to be expensive.
413 *
414 * Note that the value of this function may change
415 * as the result of other operations on a UText.
416 * Once the length of a string has been discovered, it will no longer
417 * be expensive to report it.
418 *
419 * @param ut the text to be accessed.
420 * @return TRUE if determining the length of the text could be time consuming.
421 * @stable ICU 3.4
422 */
423U_STABLE UBool U_EXPORT2
424utext_isLengthExpensive(const UText *ut);
425
426/**
427 * Returns the code point at the requested index,
428 * or U_SENTINEL (-1) if it is out of bounds.
429 *
430 * If the specified index points to the interior of a multi-unit
431 * character - one of the trail bytes of a UTF-8 sequence, for example -
432 * the complete code point will be returned.
433 *
434 * The iteration position will be set to the start of the returned code point.
435 *
436 * This function is roughly equivalent to the sequence
437 * utext_setNativeIndex(index);
438 * utext_current32();
439 * (There is a subtle difference if the index is out of bounds by being less than zero -
440 * utext_setNativeIndex(negative value) sets the index to zero, after which utext_current()
441 * will return the char at zero. utext_char32At(negative index), on the other hand, will
442 * return the U_SENTINEL value of -1.)
443 *
444 * @param ut the text to be accessed
445 * @param nativeIndex the native index of the character to be accessed. If the index points
446 * to other than the first unit of a multi-unit character, it will be adjusted
447 * to the start of the character.
448 * @return the code point at the specified index.
449 * @stable ICU 3.4
450 */
451U_STABLE UChar32 U_EXPORT2
452utext_char32At(UText *ut, int64_t nativeIndex);
453
454
455/**
456 *
457 * Get the code point at the current iteration position,
458 * or U_SENTINEL (-1) if the iteration has reached the end of
459 * the input text.
460 *
461 * @param ut the text to be accessed.
462 * @return the Unicode code point at the current iterator position.
463 * @stable ICU 3.4
464 */
465U_STABLE UChar32 U_EXPORT2
466utext_current32(UText *ut);
467
468
469/**
470 * Get the code point at the current iteration position of the UText, and
471 * advance the position to the first index following the character.
472 *
473 * If the position is at the end of the text (the index following
474 * the last character, which is also the length of the text),
475 * return U_SENTINEL (-1) and do not advance the index.
476 *
477 * This is a post-increment operation.
478 *
479 * An inline macro version of this function, UTEXT_NEXT32(),
480 * is available for performance critical use.
481 *
482 * @param ut the text to be accessed.
483 * @return the Unicode code point at the iteration position.
484 * @see UTEXT_NEXT32
485 * @stable ICU 3.4
486 */
487U_STABLE UChar32 U_EXPORT2
488utext_next32(UText *ut);
489
490
491/**
492 * Move the iterator position to the character (code point) whose
493 * index precedes the current position, and return that character.
494 * This is a pre-decrement operation.
495 *
496 * If the initial position is at the start of the text (index of 0)
497 * return U_SENTINEL (-1), and leave the position unchanged.
498 *
499 * An inline macro version of this function, UTEXT_PREVIOUS32(),
500 * is available for performance critical use.
501 *
502 * @param ut the text to be accessed.
503 * @return the previous UChar32 code point, or U_SENTINEL (-1)
504 * if the iteration has reached the start of the text.
505 * @see UTEXT_PREVIOUS32
506 * @stable ICU 3.4
507 */
508U_STABLE UChar32 U_EXPORT2
509utext_previous32(UText *ut);
510
511
512/**
513 * Set the iteration index and return the code point at that index.
514 * Leave the iteration index at the start of the following code point.
515 *
516 * This function is the most efficient and convenient way to
517 * begin a forward iteration. The results are identical to the those
518 * from the sequence
519 * \code
520 * utext_setIndex();
521 * utext_next32();
522 * \endcode
523 *
524 * @param ut the text to be accessed.
525 * @param nativeIndex Iteration index, in the native units of the text provider.
526 * @return Code point which starts at or before index,
527 * or U_SENTINEL (-1) if it is out of bounds.
528 * @stable ICU 3.4
529 */
530U_STABLE UChar32 U_EXPORT2
531utext_next32From(UText *ut, int64_t nativeIndex);
532
533
534
535/**
536 * Set the iteration index, and return the code point preceding the
537 * one specified by the initial index. Leave the iteration position
538 * at the start of the returned code point.
539 *
540 * This function is the most efficient and convenient way to
541 * begin a backwards iteration.
542 *
543 * @param ut the text to be accessed.
544 * @param nativeIndex Iteration index in the native units of the text provider.
545 * @return Code point preceding the one at the initial index,
546 * or U_SENTINEL (-1) if it is out of bounds.
547 *
548 * @stable ICU 3.4
549 */
550U_STABLE UChar32 U_EXPORT2
551utext_previous32From(UText *ut, int64_t nativeIndex);
552
553/**
554 * Get the current iterator position, which can range from 0 to
555 * the length of the text.
556 * The position is a native index into the input text, in whatever format it
557 * may have (possibly UTF-8 for example), and may not always be the same as
558 * the corresponding UChar (UTF-16) index.
559 * The returned position will always be aligned to a code point boundary.
560 *
561 * @param ut the text to be accessed.
562 * @return the current index position, in the native units of the text provider.
563 * @stable ICU 3.4
564 */
565U_STABLE int64_t U_EXPORT2
566utext_getNativeIndex(const UText *ut);
567
568/**
569 * Set the current iteration position to the nearest code point
570 * boundary at or preceding the specified index.
571 * The index is in the native units of the original input text.
572 * If the index is out of range, it will be pinned to be within
573 * the range of the input text.
574 * <p>
575 * It will usually be more efficient to begin an iteration
576 * using the functions utext_next32From() or utext_previous32From()
577 * rather than setIndex().
578 * <p>
579 * Moving the index position to an adjacent character is best done
580 * with utext_next32(), utext_previous32() or utext_moveIndex32().
581 * Attempting to do direct arithmetic on the index position is
582 * complicated by the fact that the size (in native units) of a
583 * character depends on the underlying representation of the character
584 * (UTF-8, UTF-16, UTF-32, arbitrary codepage), and is not
585 * easily knowable.
586 *
587 * @param ut the text to be accessed.
588 * @param nativeIndex the native unit index of the new iteration position.
589 * @stable ICU 3.4
590 */
591U_STABLE void U_EXPORT2
592utext_setNativeIndex(UText *ut, int64_t nativeIndex);
593
594/**
595 * Move the iterator position by delta code points. The number of code points
596 * is a signed number; a negative delta will move the iterator backwards,
597 * towards the start of the text.
598 * <p>
599 * The index is moved by <code>delta</code> code points
600 * forward or backward, but no further backward than to 0 and
601 * no further forward than to utext_nativeLength().
602 * The resulting index value will be in between 0 and length, inclusive.
603 *
604 * @param ut the text to be accessed.
605 * @param delta the signed number of code points to move the iteration position.
606 * @return TRUE if the position could be moved the requested number of positions while
607 * staying within the range [0 - text length].
608 * @stable ICU 3.4
609 */
610U_STABLE UBool U_EXPORT2
611utext_moveIndex32(UText *ut, int32_t delta);
612
613/**
614 * Get the native index of the character preceding the current position.
615 * If the iteration position is already at the start of the text, zero
616 * is returned.
617 * The value returned is the same as that obtained from the following sequence,
618 * but without the side effect of changing the iteration position.
619 *
620 * \code
621 * UText *ut = whatever;
622 * ...
623 * utext_previous(ut)
624 * utext_getNativeIndex(ut);
625 * \endcode
626 *
627 * This function is most useful during forwards iteration, where it will get the
628 * native index of the character most recently returned from utext_next().
629 *
630 * @param ut the text to be accessed
631 * @return the native index of the character preceding the current index position,
632 * or zero if the current position is at the start of the text.
633 * @stable ICU 3.6
634 */
635U_STABLE int64_t U_EXPORT2
636utext_getPreviousNativeIndex(UText *ut);
637
638
639/**
640 *
641 * Extract text from a UText into a UChar buffer. The range of text to be extracted
642 * is specified in the native indices of the UText provider. These may not necessarily
643 * be UTF-16 indices.
644 * <p>
645 * The size (number of 16 bit UChars) of the data to be extracted is returned. The
646 * full number of UChars is returned, even when the extracted text is truncated
647 * because the specified buffer size is too small.
648 * <p>
649 * The extracted string will (if you are a user) / must (if you are a text provider)
650 * be NUL-terminated if there is sufficient space in the destination buffer. This
651 * terminating NUL is not included in the returned length.
652 * <p>
653 * The iteration index is left at the position following the last extracted character.
654 *
655 * @param ut the UText from which to extract data.
656 * @param nativeStart the native index of the first character to extract.\
657 * If the specified index is out of range,
658 * it will be pinned to to be within 0 <= index <= textLength
659 * @param nativeLimit the native string index of the position following the last
660 * character to extract. If the specified index is out of range,
661 * it will be pinned to to be within 0 <= index <= textLength.
662 * nativeLimit must be >= nativeStart.
663 * @param dest the UChar (UTF-16) buffer into which the extracted text is placed
664 * @param destCapacity The size, in UChars, of the destination buffer. May be zero
665 * for precomputing the required size.
666 * @param status receives any error status.
667 * U_BUFFER_OVERFLOW_ERROR: the extracted text was truncated because the
668 * buffer was too small. Returns number of UChars for preflighting.
669 * @return Number of UChars in the data to be extracted. Does not include a trailing NUL.
670 *
671 * @stable ICU 3.4
672 */
673U_STABLE int32_t U_EXPORT2
674utext_extract(UText *ut,
675 int64_t nativeStart, int64_t nativeLimit,
676 UChar *dest, int32_t destCapacity,
677 UErrorCode *status);
678
679
680
681/************************************************************************************
682 *
683 * #define inline versions of selected performance-critical text access functions
684 * Caution: do not use auto increment++ or decrement-- expressions
685 * as parameters to these macros.
686 *
687 * For most use, where there is no extreme performance constraint, the
688 * normal, non-inline functions are a better choice. The resulting code
689 * will be smaller, and, if the need ever arises, easier to debug.
690 *
691 * These are implemented as #defines rather than real functions
692 * because there is no fully portable way to do inline functions in plain C.
693 *
694 ************************************************************************************/
695
696#ifndef U_HIDE_INTERNAL_API
697/**
698 * inline version of utext_current32(), for performance-critical situations.
699 *
700 * Get the code point at the current iteration position of the UText.
701 * Returns U_SENTINEL (-1) if the position is at the end of the
702 * text.
703 *
704 * @internal ICU 4.4 technology preview
705 */
706#define UTEXT_CURRENT32(ut) \
707 ((ut)->chunkOffset < (ut)->chunkLength && ((ut)->chunkContents)[(ut)->chunkOffset]<0xd800 ? \
708 ((ut)->chunkContents)[((ut)->chunkOffset)] : utext_current32(ut))
709#endif /* U_HIDE_INTERNAL_API */
710
711/**
712 * inline version of utext_next32(), for performance-critical situations.
713 *
714 * Get the code point at the current iteration position of the UText, and
715 * advance the position to the first index following the character.
716 * This is a post-increment operation.
717 * Returns U_SENTINEL (-1) if the position is at the end of the
718 * text.
719 *
720 * @stable ICU 3.4
721 */
722#define UTEXT_NEXT32(ut) \
723 ((ut)->chunkOffset < (ut)->chunkLength && ((ut)->chunkContents)[(ut)->chunkOffset]<0xd800 ? \
724 ((ut)->chunkContents)[((ut)->chunkOffset)++] : utext_next32(ut))
725
726/**
727 * inline version of utext_previous32(), for performance-critical situations.
728 *
729 * Move the iterator position to the character (code point) whose
730 * index precedes the current position, and return that character.
731 * This is a pre-decrement operation.
732 * Returns U_SENTINEL (-1) if the position is at the start of the text.
733 *
734 * @stable ICU 3.4
735 */
736#define UTEXT_PREVIOUS32(ut) \
737 ((ut)->chunkOffset > 0 && \
738 (ut)->chunkContents[(ut)->chunkOffset-1] < 0xd800 ? \
739 (ut)->chunkContents[--((ut)->chunkOffset)] : utext_previous32(ut))
740
741/**
742 * inline version of utext_getNativeIndex(), for performance-critical situations.
743 *
744 * Get the current iterator position, which can range from 0 to
745 * the length of the text.
746 * The position is a native index into the input text, in whatever format it
747 * may have (possibly UTF-8 for example), and may not always be the same as
748 * the corresponding UChar (UTF-16) index.
749 * The returned position will always be aligned to a code point boundary.
750 *
751 * @stable ICU 3.6
752 */
753#define UTEXT_GETNATIVEINDEX(ut) \
754 ((ut)->chunkOffset <= (ut)->nativeIndexingLimit? \
755 (ut)->chunkNativeStart+(ut)->chunkOffset : \
756 (ut)->pFuncs->mapOffsetToNative(ut))
757
758/**
759 * inline version of utext_setNativeIndex(), for performance-critical situations.
760 *
761 * Set the current iteration position to the nearest code point
762 * boundary at or preceding the specified index.
763 * The index is in the native units of the original input text.
764 * If the index is out of range, it will be pinned to be within
765 * the range of the input text.
766 *
767 * @stable ICU 3.8
768 */
769#define UTEXT_SETNATIVEINDEX(ut, ix) \
770 { int64_t __offset = (ix) - (ut)->chunkNativeStart; \
771 if (__offset>=0 && __offset<(int64_t)(ut)->nativeIndexingLimit && (ut)->chunkContents[__offset]<0xdc00) { \
772 (ut)->chunkOffset=(int32_t)__offset; \
773 } else { \
774 utext_setNativeIndex((ut), (ix)); } }
775
776
777
778/************************************************************************************
779 *
780 * Functions related to writing or modifying the text.
781 * These will work only with modifiable UTexts. Attempting to
782 * modify a read-only UText will return an error status.
783 *
784 ************************************************************************************/
785
786
787/**
788 * Return TRUE if the text can be written (modified) with utext_replace() or
789 * utext_copy(). For the text to be writable, the text provider must
790 * be of a type that supports writing and the UText must not be frozen.
791 *
792 * Attempting to modify text when utext_isWriteable() is FALSE will fail -
793 * the text will not be modified, and an error will be returned from the function
794 * that attempted the modification.
795 *
796 * @param ut the UText to be tested.
797 * @return TRUE if the text is modifiable.
798 *
799 * @see utext_freeze()
800 * @see utext_replace()
801 * @see utext_copy()
802 * @stable ICU 3.4
803 *
804 */
805U_STABLE UBool U_EXPORT2
806utext_isWritable(const UText *ut);
807
808
809/**
810 * Test whether there is meta data associated with the text.
811 * @see Replaceable::hasMetaData()
812 *
813 * @param ut The UText to be tested
814 * @return TRUE if the underlying text includes meta data.
815 * @stable ICU 3.4
816 */
817U_STABLE UBool U_EXPORT2
818utext_hasMetaData(const UText *ut);
819
820
821/**
822 * Replace a range of the original text with a replacement text.
823 *
824 * Leaves the current iteration position at the position following the
825 * newly inserted replacement text.
826 *
827 * This function is only available on UText types that support writing,
828 * that is, ones where utext_isWritable() returns TRUE.
829 *
830 * When using this function, there should be only a single UText opened onto the
831 * underlying native text string. Behavior after a replace operation
832 * on a UText is undefined for any other additional UTexts that refer to the
833 * modified string.
834 *
835 * @param ut the UText representing the text to be operated on.
836 * @param nativeStart the native index of the start of the region to be replaced
837 * @param nativeLimit the native index of the character following the region to be replaced.
838 * @param replacementText pointer to the replacement text
839 * @param replacementLength length of the replacement text, or -1 if the text is NUL terminated.
840 * @param status receives any error status. Possible errors include
841 * U_NO_WRITE_PERMISSION
842 *
843 * @return The signed number of (native) storage units by which
844 * the length of the text expanded or contracted.
845 *
846 * @stable ICU 3.4
847 */
848U_STABLE int32_t U_EXPORT2
849utext_replace(UText *ut,
850 int64_t nativeStart, int64_t nativeLimit,
851 const UChar *replacementText, int32_t replacementLength,
852 UErrorCode *status);
853
854
855
856/**
857 *
858 * Copy or move a substring from one position to another within the text,
859 * while retaining any metadata associated with the text.
860 * This function is used to duplicate or reorder substrings.
861 * The destination index must not overlap the source range.
862 *
863 * The text to be copied or moved is inserted at destIndex;
864 * it does not replace or overwrite any existing text.
865 *
866 * The iteration position is left following the newly inserted text
867 * at the destination position.
868 *
869 * This function is only available on UText types that support writing,
870 * that is, ones where utext_isWritable() returns TRUE.
871 *
872 * When using this function, there should be only a single UText opened onto the
873 * underlying native text string. Behavior after a copy operation
874 * on a UText is undefined in any other additional UTexts that refer to the
875 * modified string.
876 *
877 * @param ut The UText representing the text to be operated on.
878 * @param nativeStart The native index of the start of the region to be copied or moved
879 * @param nativeLimit The native index of the character position following the region
880 * to be copied.
881 * @param destIndex The native destination index to which the source substring is
882 * copied or moved.
883 * @param move If TRUE, then the substring is moved, not copied/duplicated.
884 * @param status receives any error status. Possible errors include U_NO_WRITE_PERMISSION
885 *
886 * @stable ICU 3.4
887 */
888U_STABLE void U_EXPORT2
889utext_copy(UText *ut,
890 int64_t nativeStart, int64_t nativeLimit,
891 int64_t destIndex,
892 UBool move,
893 UErrorCode *status);
894
895
896/**
897 * <p>
898 * Freeze a UText. This prevents any modification to the underlying text itself
899 * by means of functions operating on this UText.
900 * </p>
901 * <p>
902 * Once frozen, a UText can not be unfrozen. The intent is to ensure
903 * that a the text underlying a frozen UText wrapper cannot be modified via that UText.
904 * </p>
905 * <p>
906 * Caution: freezing a UText will disable changes made via the specific
907 * frozen UText wrapper only; it will not have any effect on the ability to
908 * directly modify the text by bypassing the UText. Any such backdoor modifications
909 * are always an error while UText access is occuring because the underlying
910 * text can get out of sync with UText's buffering.
911 * </p>
912 *
913 * @param ut The UText to be frozen.
914 * @see utext_isWritable()
915 * @stable ICU 3.6
916 */
917U_STABLE void U_EXPORT2
918utext_freeze(UText *ut);
919
920
921/**
922 * UText provider properties (bit field indexes).
923 *
924 * @see UText
925 * @stable ICU 3.4
926 */
927enum {
928 /**
929 * It is potentially time consuming for the provider to determine the length of the text.
930 * @stable ICU 3.4
931 */
932 UTEXT_PROVIDER_LENGTH_IS_EXPENSIVE = 1,
933 /**
934 * Text chunks remain valid and usable until the text object is modified or
935 * deleted, not just until the next time the access() function is called
936 * (which is the default).
937 * @stable ICU 3.4
938 */
939 UTEXT_PROVIDER_STABLE_CHUNKS = 2,
940 /**
941 * The provider supports modifying the text via the replace() and copy()
942 * functions.
943 * @see Replaceable
944 * @stable ICU 3.4
945 */
946 UTEXT_PROVIDER_WRITABLE = 3,
947 /**
948 * There is meta data associated with the text.
949 * @see Replaceable::hasMetaData()
950 * @stable ICU 3.4
951 */
952 UTEXT_PROVIDER_HAS_META_DATA = 4,
953 /**
954 * Text provider owns the text storage.
955 * Generally occurs as the result of a deep clone of the UText.
956 * When closing the UText, the associated text must
957 * also be closed/deleted/freed/ whatever is appropriate.
958 * @stable ICU 3.6
959 */
960 UTEXT_PROVIDER_OWNS_TEXT = 5
961};
962
963/**
964 * Function type declaration for UText.clone().
965 *
966 * clone a UText. Much like opening a UText where the source text is itself
967 * another UText.
968 *
969 * A deep clone will copy both the UText data structures and the underlying text.
970 * The original and cloned UText will operate completely independently; modifications
971 * made to the text in one will not effect the other. Text providers are not
972 * required to support deep clones. The user of clone() must check the status return
973 * and be prepared to handle failures.
974 *
975 * A shallow clone replicates only the UText data structures; it does not make
976 * a copy of the underlying text. Shallow clones can be used as an efficient way to
977 * have multiple iterators active in a single text string that is not being
978 * modified.
979 *
980 * A shallow clone operation must not fail except for truly exceptional conditions such
981 * as memory allocation failures.
982 *
983 * A UText and its clone may be safely concurrently accessed by separate threads.
984 * This is true for both shallow and deep clones.
985 * It is the responsibility of the Text Provider to ensure that this thread safety
986 * constraint is met.
987
988 *
989 * @param dest A UText struct to be filled in with the result of the clone operation,
990 * or NULL if the clone function should heap-allocate a new UText struct.
991 * @param src The UText to be cloned.
992 * @param deep TRUE to request a deep clone, FALSE for a shallow clone.
993 * @param status Errors are returned here. For deep clones, U_UNSUPPORTED_ERROR
994 * should be returned if the text provider is unable to clone the
995 * original text.
996 * @return The newly created clone, or NULL if the clone operation failed.
997 *
998 * @stable ICU 3.4
999 */
1000typedef UText * U_CALLCONV
1001UTextClone(UText *dest, const UText *src, UBool deep, UErrorCode *status);
1002
1003
1004/**
1005 * Function type declaration for UText.nativeLength().
1006 *
1007 * @param ut the UText to get the length of.
1008 * @return the length, in the native units of the original text string.
1009 * @see UText
1010 * @stable ICU 3.4
1011 */
1012typedef int64_t U_CALLCONV
1013UTextNativeLength(UText *ut);
1014
1015/**
1016 * Function type declaration for UText.access(). Get the description of the text chunk
1017 * containing the text at a requested native index. The UText's iteration
1018 * position will be left at the requested index. If the index is out
1019 * of bounds, the iteration position will be left at the start or end
1020 * of the string, as appropriate.
1021 *
1022 * Chunks must begin and end on code point boundaries. A single code point
1023 * comprised of multiple storage units must never span a chunk boundary.
1024 *
1025 *
1026 * @param ut the UText being accessed.
1027 * @param nativeIndex Requested index of the text to be accessed.
1028 * @param forward If TRUE, then the returned chunk must contain text
1029 * starting from the index, so that start<=index<limit.
1030 * If FALSE, then the returned chunk must contain text
1031 * before the index, so that start<index<=limit.
1032 * @return True if the requested index could be accessed. The chunk
1033 * will contain the requested text.
1034 * False value if a chunk cannot be accessed
1035 * (the requested index is out of bounds).
1036 *
1037 * @see UText
1038 * @stable ICU 3.4
1039 */
1040typedef UBool U_CALLCONV
1041UTextAccess(UText *ut, int64_t nativeIndex, UBool forward);
1042
1043/**
1044 * Function type declaration for UText.extract().
1045 *
1046 * Extract text from a UText into a UChar buffer. The range of text to be extracted
1047 * is specified in the native indices of the UText provider. These may not necessarily
1048 * be UTF-16 indices.
1049 * <p>
1050 * The size (number of 16 bit UChars) in the data to be extracted is returned. The
1051 * full amount is returned, even when the specified buffer size is smaller.
1052 * <p>
1053 * The extracted string will (if you are a user) / must (if you are a text provider)
1054 * be NUL-terminated if there is sufficient space in the destination buffer.
1055 *
1056 * @param ut the UText from which to extract data.
1057 * @param nativeStart the native index of the first character to extract.
1058 * @param nativeLimit the native string index of the position following the last
1059 * character to extract.
1060 * @param dest the UChar (UTF-16) buffer into which the extracted text is placed
1061 * @param destCapacity The size, in UChars, of the destination buffer. May be zero
1062 * for precomputing the required size.
1063 * @param status receives any error status.
1064 * If U_BUFFER_OVERFLOW_ERROR: Returns number of UChars for
1065 * preflighting.
1066 * @return Number of UChars in the data. Does not include a trailing NUL.
1067 *
1068 * @stable ICU 3.4
1069 */
1070typedef int32_t U_CALLCONV
1071UTextExtract(UText *ut,
1072 int64_t nativeStart, int64_t nativeLimit,
1073 UChar *dest, int32_t destCapacity,
1074 UErrorCode *status);
1075
1076/**
1077 * Function type declaration for UText.replace().
1078 *
1079 * Replace a range of the original text with a replacement text.
1080 *
1081 * Leaves the current iteration position at the position following the
1082 * newly inserted replacement text.
1083 *
1084 * This function need only be implemented on UText types that support writing.
1085 *
1086 * When using this function, there should be only a single UText opened onto the
1087 * underlying native text string. The function is responsible for updating the
1088 * text chunk within the UText to reflect the updated iteration position,
1089 * taking into account any changes to the underlying string's structure caused
1090 * by the replace operation.
1091 *
1092 * @param ut the UText representing the text to be operated on.
1093 * @param nativeStart the index of the start of the region to be replaced
1094 * @param nativeLimit the index of the character following the region to be replaced.
1095 * @param replacementText pointer to the replacement text
1096 * @param replacmentLength length of the replacement text in UChars, or -1 if the text is NUL terminated.
1097 * @param status receives any error status. Possible errors include
1098 * U_NO_WRITE_PERMISSION
1099 *
1100 * @return The signed number of (native) storage units by which
1101 * the length of the text expanded or contracted.
1102 *
1103 * @stable ICU 3.4
1104 */
1105typedef int32_t U_CALLCONV
1106UTextReplace(UText *ut,
1107 int64_t nativeStart, int64_t nativeLimit,
1108 const UChar *replacementText, int32_t replacmentLength,
1109 UErrorCode *status);
1110
1111/**
1112 * Function type declaration for UText.copy().
1113 *
1114 * Copy or move a substring from one position to another within the text,
1115 * while retaining any metadata associated with the text.
1116 * This function is used to duplicate or reorder substrings.
1117 * The destination index must not overlap the source range.
1118 *
1119 * The text to be copied or moved is inserted at destIndex;
1120 * it does not replace or overwrite any existing text.
1121 *
1122 * This function need only be implemented for UText types that support writing.
1123 *
1124 * When using this function, there should be only a single UText opened onto the
1125 * underlying native text string. The function is responsible for updating the
1126 * text chunk within the UText to reflect the updated iteration position,
1127 * taking into account any changes to the underlying string's structure caused
1128 * by the replace operation.
1129 *
1130 * @param ut The UText representing the text to be operated on.
1131 * @param nativeStart The index of the start of the region to be copied or moved
1132 * @param nativeLimit The index of the character following the region to be replaced.
1133 * @param nativeDest The destination index to which the source substring is copied or moved.
1134 * @param move If TRUE, then the substring is moved, not copied/duplicated.
1135 * @param status receives any error status. Possible errors include U_NO_WRITE_PERMISSION
1136 *
1137 * @stable ICU 3.4
1138 */
1139typedef void U_CALLCONV
1140UTextCopy(UText *ut,
1141 int64_t nativeStart, int64_t nativeLimit,
1142 int64_t nativeDest,
1143 UBool move,
1144 UErrorCode *status);
1145
1146/**
1147 * Function type declaration for UText.mapOffsetToNative().
1148 * Map from the current UChar offset within the current text chunk to
1149 * the corresponding native index in the original source text.
1150 *
1151 * This is required only for text providers that do not use native UTF-16 indexes.
1152 *
1153 * @param ut the UText.
1154 * @return Absolute (native) index corresponding to chunkOffset in the current chunk.
1155 * The returned native index should always be to a code point boundary.
1156 *
1157 * @stable ICU 3.4
1158 */
1159typedef int64_t U_CALLCONV
1160UTextMapOffsetToNative(const UText *ut);
1161
1162/**
1163 * Function type declaration for UText.mapIndexToUTF16().
1164 * Map from a native index to a UChar offset within a text chunk.
1165 * Behavior is undefined if the native index does not fall within the
1166 * current chunk.
1167 *
1168 * This function is required only for text providers that do not use native UTF-16 indexes.
1169 *
1170 * @param ut The UText containing the text chunk.
1171 * @param nativeIndex Absolute (native) text index, chunk->start<=index<=chunk->limit.
1172 * @return Chunk-relative UTF-16 offset corresponding to the specified native
1173 * index.
1174 *
1175 * @stable ICU 3.4
1176 */
1177typedef int32_t U_CALLCONV
1178UTextMapNativeIndexToUTF16(const UText *ut, int64_t nativeIndex);
1179
1180
1181/**
1182 * Function type declaration for UText.utextClose().
1183 *
1184 * A Text Provider close function is only required for provider types that make
1185 * allocations in their open function (or other functions) that must be
1186 * cleaned when the UText is closed.
1187 *
1188 * The allocation of the UText struct itself and any "extra" storage
1189 * associated with the UText is handled by the common UText implementation
1190 * and does not require provider specific cleanup in a close function.
1191 *
1192 * Most UText provider implementations do not need to implement this function.
1193 *
1194 * @param ut A UText object to be closed.
1195 *
1196 * @stable ICU 3.4
1197 */
1198typedef void U_CALLCONV
1199UTextClose(UText *ut);
1200
1201
1202/**
1203 * (public) Function dispatch table for UText.
1204 * Conceptually very much like a C++ Virtual Function Table.
1205 * This struct defines the organization of the table.
1206 * Each text provider implementation must provide an
1207 * actual table that is initialized with the appropriate functions
1208 * for the type of text being handled.
1209 * @stable ICU 3.6
1210 */
1211struct UTextFuncs {
1212 /**
1213 * (public) Function table size, sizeof(UTextFuncs)
1214 * Intended for use should the table grow to accommodate added
1215 * functions in the future, to allow tests for older format
1216 * function tables that do not contain the extensions.
1217 *
1218 * Fields are placed for optimal alignment on
1219 * 32/64/128-bit-pointer machines, by normally grouping together
1220 * 4 32-bit fields,
1221 * 4 pointers,
1222 * 2 64-bit fields
1223 * in sequence.
1224 * @stable ICU 3.6
1225 */
1226 int32_t tableSize;
1227
1228 /**
1229 * (private) Alignment padding.
1230 * Do not use, reserved for use by the UText framework only.
1231 * @internal
1232 */
1233 int32_t reserved1, /** @internal */ reserved2, /** @internal */ reserved3;
1234
1235
1236 /**
1237 * (public) Function pointer for UTextClone
1238 *
1239 * @see UTextClone
1240 * @stable ICU 3.6
1241 */
1242 UTextClone *clone;
1243
1244 /**
1245 * (public) function pointer for UTextLength
1246 * May be expensive to compute!
1247 *
1248 * @see UTextLength
1249 * @stable ICU 3.6
1250 */
1251 UTextNativeLength *nativeLength;
1252
1253 /**
1254 * (public) Function pointer for UTextAccess.
1255 *
1256 * @see UTextAccess
1257 * @stable ICU 3.6
1258 */
1259 UTextAccess *access;
1260
1261 /**
1262 * (public) Function pointer for UTextExtract.
1263 *
1264 * @see UTextExtract
1265 * @stable ICU 3.6
1266 */
1267 UTextExtract *extract;
1268
1269 /**
1270 * (public) Function pointer for UTextReplace.
1271 *
1272 * @see UTextReplace
1273 * @stable ICU 3.6
1274 */
1275 UTextReplace *replace;
1276
1277 /**
1278 * (public) Function pointer for UTextCopy.
1279 *
1280 * @see UTextCopy
1281 * @stable ICU 3.6
1282 */
1283 UTextCopy *copy;
1284
1285 /**
1286 * (public) Function pointer for UTextMapOffsetToNative.
1287 *
1288 * @see UTextMapOffsetToNative
1289 * @stable ICU 3.6
1290 */
1291 UTextMapOffsetToNative *mapOffsetToNative;
1292
1293 /**
1294 * (public) Function pointer for UTextMapNativeIndexToUTF16.
1295 *
1296 * @see UTextMapNativeIndexToUTF16
1297 * @stable ICU 3.6
1298 */
1299 UTextMapNativeIndexToUTF16 *mapNativeIndexToUTF16;
1300
1301 /**
1302 * (public) Function pointer for UTextClose.
1303 *
1304 * @see UTextClose
1305 * @stable ICU 3.6
1306 */
1307 UTextClose *close;
1308
1309 /**
1310 * (private) Spare function pointer
1311 * @internal
1312 */
1313 UTextClose *spare1;
1314
1315 /**
1316 * (private) Spare function pointer
1317 * @internal
1318 */
1319 UTextClose *spare2;
1320
1321 /**
1322 * (private) Spare function pointer
1323 * @internal
1324 */
1325 UTextClose *spare3;
1326
1327};
1328/**
1329 * Function dispatch table for UText
1330 * @see UTextFuncs
1331 */
1332typedef struct UTextFuncs UTextFuncs;
1333
1334 /**
1335 * UText struct. Provides the interface between the generic UText access code
1336 * and the UText provider code that works on specific kinds of
1337 * text (UTF-8, noncontiguous UTF-16, whatever.)
1338 *
1339 * Applications that are using predefined types of text providers
1340 * to pass text data to ICU services will have no need to view the
1341 * internals of the UText structs that they open.
1342 *
1343 * @stable ICU 3.6
1344 */
1345struct UText {
1346 /**
1347 * (private) Magic. Used to help detect when UText functions are handed
1348 * invalid or uninitialized UText structs.
1349 * utext_openXYZ() functions take an initialized,
1350 * but not necessarily open, UText struct as an
1351 * optional fill-in parameter. This magic field
1352 * is used to check for that initialization.
1353 * Text provider close functions must NOT clear
1354 * the magic field because that would prevent
1355 * reuse of the UText struct.
1356 * @internal
1357 */
1358 uint32_t magic;
1359
1360
1361 /**
1362 * (private) Flags for managing the allocation and freeing of
1363 * memory associated with this UText.
1364 * @internal
1365 */
1366 int32_t flags;
1367
1368
1369 /**
1370 * Text provider properties. This set of flags is maintained by the
1371 * text provider implementation.
1372 * @stable ICU 3.4
1373 */
1374 int32_t providerProperties;
1375
1376 /**
1377 * (public) sizeOfStruct=sizeof(UText)
1378 * Allows possible backward compatible extension.
1379 *
1380 * @stable ICU 3.4
1381 */
1382 int32_t sizeOfStruct;
1383
1384 /* ------ 16 byte alignment boundary ----------- */
1385
1386
1387 /**
1388 * (protected) Native index of the first character position following
1389 * the current chunk.
1390 * @stable ICU 3.6
1391 */
1392 int64_t chunkNativeLimit;
1393
1394 /**
1395 * (protected) Size in bytes of the extra space (pExtra).
1396 * @stable ICU 3.4
1397 */
1398 int32_t extraSize;
1399
1400 /**
1401 * (protected) The highest chunk offset where native indexing and
1402 * chunk (UTF-16) indexing correspond. For UTF-16 sources, value
1403 * will be equal to chunkLength.
1404 *
1405 * @stable ICU 3.6
1406 */
1407 int32_t nativeIndexingLimit;
1408
1409 /* ---- 16 byte alignment boundary------ */
1410
1411 /**
1412 * (protected) Native index of the first character in the text chunk.
1413 * @stable ICU 3.6
1414 */
1415 int64_t chunkNativeStart;
1416
1417 /**
1418 * (protected) Current iteration position within the text chunk (UTF-16 buffer).
1419 * This is the index to the character that will be returned by utext_next32().
1420 * @stable ICU 3.6
1421 */
1422 int32_t chunkOffset;
1423
1424 /**
1425 * (protected) Length the text chunk (UTF-16 buffer), in UChars.
1426 * @stable ICU 3.6
1427 */
1428 int32_t chunkLength;
1429
1430 /* ---- 16 byte alignment boundary-- */
1431
1432
1433 /**
1434 * (protected) pointer to a chunk of text in UTF-16 format.
1435 * May refer either to original storage of the source of the text, or
1436 * if conversion was required, to a buffer owned by the UText.
1437 * @stable ICU 3.6
1438 */
1439 const UChar *chunkContents;
1440
1441 /**
1442 * (public) Pointer to Dispatch table for accessing functions for this UText.
1443 * @stable ICU 3.6
1444 */
1445 const UTextFuncs *pFuncs;
1446
1447 /**
1448 * (protected) Pointer to additional space requested by the
1449 * text provider during the utext_open operation.
1450 * @stable ICU 3.4
1451 */
1452 void *pExtra;
1453
1454 /**
1455 * (protected) Pointer to string or text-containin object or similar.
1456 * This is the source of the text that this UText is wrapping, in a format
1457 * that is known to the text provider functions.
1458 * @stable ICU 3.4
1459 */
1460 const void *context;
1461
1462 /* --- 16 byte alignment boundary--- */
1463
1464 /**
1465 * (protected) Pointer fields available for use by the text provider.
1466 * Not used by UText common code.
1467 * @stable ICU 3.6
1468 */
1469 const void *p;
1470 /**
1471 * (protected) Pointer fields available for use by the text provider.
1472 * Not used by UText common code.
1473 * @stable ICU 3.6
1474 */
1475 const void *q;
1476 /**
1477 * (protected) Pointer fields available for use by the text provider.
1478 * Not used by UText common code.
1479 * @stable ICU 3.6
1480 */
1481 const void *r;
1482
1483 /**
1484 * Private field reserved for future use by the UText framework
1485 * itself. This is not to be touched by the text providers.
1486 * @internal ICU 3.4
1487 */
1488 void *privP;
1489
1490
1491 /* --- 16 byte alignment boundary--- */
1492
1493
1494 /**
1495 * (protected) Integer field reserved for use by the text provider.
1496 * Not used by the UText framework, or by the client (user) of the UText.
1497 * @stable ICU 3.4
1498 */
1499 int64_t a;
1500
1501 /**
1502 * (protected) Integer field reserved for use by the text provider.
1503 * Not used by the UText framework, or by the client (user) of the UText.
1504 * @stable ICU 3.4
1505 */
1506 int32_t b;
1507
1508 /**
1509 * (protected) Integer field reserved for use by the text provider.
1510 * Not used by the UText framework, or by the client (user) of the UText.
1511 * @stable ICU 3.4
1512 */
1513 int32_t c;
1514
1515 /* ---- 16 byte alignment boundary---- */
1516
1517
1518 /**
1519 * Private field reserved for future use by the UText framework
1520 * itself. This is not to be touched by the text providers.
1521 * @internal ICU 3.4
1522 */
1523 int64_t privA;
1524 /**
1525 * Private field reserved for future use by the UText framework
1526 * itself. This is not to be touched by the text providers.
1527 * @internal ICU 3.4
1528 */
1529 int32_t privB;
1530 /**
1531 * Private field reserved for future use by the UText framework
1532 * itself. This is not to be touched by the text providers.
1533 * @internal ICU 3.4
1534 */
1535 int32_t privC;
1536};
1537
1538
1539/**
1540 * Common function for use by Text Provider implementations to allocate and/or initialize
1541 * a new UText struct. To be called in the implementation of utext_open() functions.
1542 * If the supplied UText parameter is null, a new UText struct will be allocated on the heap.
1543 * If the supplied UText is already open, the provider's close function will be called
1544 * so that the struct can be reused by the open that is in progress.
1545 *
1546 * @param ut pointer to a UText struct to be re-used, or null if a new UText
1547 * should be allocated.
1548 * @param extraSpace The amount of additional space to be allocated as part
1549 * of this UText, for use by types of providers that require
1550 * additional storage.
1551 * @param status Errors are returned here.
1552 * @return pointer to the UText, allocated if necessary, with extra space set up if requested.
1553 * @stable ICU 3.4
1554 */
1555U_STABLE UText * U_EXPORT2
1556utext_setup(UText *ut, int32_t extraSpace, UErrorCode *status);
1557
1558#ifndef U_HIDE_INTERNAL_API
1559/**
1560 * @internal
1561 * Value used to help identify correctly initialized UText structs.
1562 * Note: must be publicly visible so that UTEXT_INITIALIZER can access it.
1563 */
1564enum {
1565 UTEXT_MAGIC = 0x345ad82c
1566};
1567#endif /* U_HIDE_INTERNAL_API */
1568
1569/**
1570 * initializer to be used with local (stack) instances of a UText
1571 * struct. UText structs must be initialized before passing
1572 * them to one of the utext_open functions.
1573 *
1574 * @stable ICU 3.6
1575 */
1576#define UTEXT_INITIALIZER { \
1577 UTEXT_MAGIC, /* magic */ \
1578 0, /* flags */ \
1579 0, /* providerProps */ \
1580 sizeof(UText), /* sizeOfStruct */ \
1581 0, /* chunkNativeLimit */ \
1582 0, /* extraSize */ \
1583 0, /* nativeIndexingLimit */ \
1584 0, /* chunkNativeStart */ \
1585 0, /* chunkOffset */ \
1586 0, /* chunkLength */ \
1587 NULL, /* chunkContents */ \
1588 NULL, /* pFuncs */ \
1589 NULL, /* pExtra */ \
1590 NULL, /* context */ \
1591 NULL, NULL, NULL, /* p, q, r */ \
1592 NULL, /* privP */ \
1593 0, 0, 0, /* a, b, c */ \
1594 0, 0, 0 /* privA,B,C, */ \
1595 }
1596
1597
1598U_CDECL_END
1599
1600
1601
1602#endif
1603