codekingpro/portable-devtools
115k
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/**
187 * Open a read-only UText implementation for UTF-8 strings.
188 *
189 * \htmlonly
190 * Any invalid UTF-8 in the input will be handled in this way:
191 * a sequence of bytes that has the form of a truncated, but otherwise valid,
192 * UTF-8 sequence will be replaced by a single unicode replacement character, \uFFFD.
193 * Any other illegal bytes will each be replaced by a \uFFFD.
194 * \endhtmlonly
195 *
196 * @param ut Pointer to a UText struct. If NULL, a new UText will be created.
197 * If non-NULL, must refer to an initialized UText struct, which will then
198 * be reset to reference the specified UTF-8 string.
199 * @param s A UTF-8 string. Must not be NULL.
200 * @param length The length of the UTF-8 string in bytes, or -1 if the string is
201 * zero terminated.
202 * @param status Errors are returned here.
203 * @return A pointer to the UText. If a pre-allocated UText was provided, it
204 * will always be used and returned.
205 * @stable ICU 3.4
206 */
207U_STABLE UText * U_EXPORT2
208utext_openUTF8(UText *ut, const char *s, int64_t length, UErrorCode *status);
209
210
211/**
212 * Open a read-only UText for UChar * string.
213 *
214 * @param ut Pointer to a UText struct. If NULL, a new UText will be created.
215 * If non-NULL, must refer to an initialized UText struct, which will then
216 * be reset to reference the specified UChar string.
217 * @param s A UChar (UTF-16) string
218 * @param length The number of UChars in the input string, or -1 if the string is
219 * zero terminated.
220 * @param status Errors are returned here.
221 * @return A pointer to the UText. If a pre-allocated UText was provided, it
222 * will always be used and returned.
223 * @stable ICU 3.4
224 */
225U_STABLE UText * U_EXPORT2
226utext_openUChars(UText *ut, const UChar *s, int64_t length, UErrorCode *status);
227
228
229#if U_SHOW_CPLUSPLUS_API
230/**
231 * Open a writable UText for a non-const UnicodeString.
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 input string.
236 * @param s A UnicodeString.
237 * @param status Errors are returned here.
238 * @return Pointer to the UText. If a UText was supplied as input, this
239 * will always be used and returned.
240 * @stable ICU 3.4
241 */
242U_STABLE UText * U_EXPORT2
243utext_openUnicodeString(UText *ut, icu::UnicodeString *s, UErrorCode *status);
244
245
246/**
247 * Open a UText for a const UnicodeString. The resulting UText will not be writable.
248 *
249 * @param ut Pointer to a UText struct. If NULL, a new UText will be created.
250 * If non-NULL, must refer to an initialized UText struct, which will then
251 * be reset to reference the specified input string.
252 * @param s A const UnicodeString to be wrapped.
253 * @param status Errors are returned here.
254 * @return Pointer to the UText. If a UText was supplied as input, this
255 * will always be used and returned.
256 * @stable ICU 3.4
257 */
258U_STABLE UText * U_EXPORT2
259utext_openConstUnicodeString(UText *ut, const icu::UnicodeString *s, UErrorCode *status);
260
261
262/**
263 * Open a writable UText implementation for an ICU Replaceable object.
264 * @param ut Pointer to a UText struct. If NULL, a new UText will be created.
265 * If non-NULL, must refer to an already existing UText, which will then
266 * be reset to reference the specified replaceable text.
267 * @param rep A Replaceable text object.
268 * @param status Errors are returned here.
269 * @return Pointer to the UText. If a UText was supplied as input, this
270 * will always be used and returned.
271 * @see Replaceable
272 * @stable ICU 3.4
273 */
274U_STABLE UText * U_EXPORT2
275utext_openReplaceable(UText *ut, icu::Replaceable *rep, UErrorCode *status);
276
277/**
278 * Open a UText implementation over an ICU CharacterIterator.
279 * @param ut Pointer to a UText struct. If NULL, a new UText will be created.
280 * If non-NULL, must refer to an already existing UText, which will then
281 * be reset to reference the specified replaceable text.
282 * @param ci A Character Iterator.
283 * @param status Errors are returned here.
284 * @return Pointer to the UText. If a UText was supplied as input, this
285 * will always be used and returned.
286 * @see Replaceable
287 * @stable ICU 3.4
288 */
289U_STABLE UText * U_EXPORT2
290utext_openCharacterIterator(UText *ut, icu::CharacterIterator *ci, UErrorCode *status);
291
292#endif
293
294
295/**
296 * Clone a UText. This is much like opening a UText where the source text is itself
297 * another UText.
298 *
299 * A deep clone will copy both the UText data structures and the underlying text.
300 * The original and cloned UText will operate completely independently; modifications
301 * made to the text in one will not affect the other. Text providers are not
302 * required to support deep clones. The user of clone() must check the status return
303 * and be prepared to handle failures.
304 *
305 * The standard UText implementations for UTF8, UChar *, UnicodeString and
306 * Replaceable all support deep cloning.
307 *
308 * The UText returned from a deep clone will be writable, assuming that the text
309 * provider is able to support writing, even if the source UText had been made
310 * non-writable by means of UText_freeze().
311 *
312 * A shallow clone replicates only the UText data structures; it does not make
313 * a copy of the underlying text. Shallow clones can be used as an efficient way to
314 * have multiple iterators active in a single text string that is not being
315 * modified.
316 *
317 * A shallow clone operation will not fail, barring truly exceptional conditions such
318 * as memory allocation failures.
319 *
320 * Shallow UText clones should be avoided if the UText functions that modify the
321 * text are expected to be used, either on the original or the cloned UText.
322 * Any such modifications can cause unpredictable behavior. Read Only
323 * shallow clones provide some protection against errors of this type by
324 * disabling text modification via the cloned UText.
325 *
326 * A shallow clone made with the readOnly parameter == FALSE will preserve the
327 * utext_isWritable() state of the source object. Note, however, that
328 * write operations must be avoided while more than one UText exists that refer
329 * to the same underlying text.
330 *
331 * A UText and its clone may be safely concurrently accessed by separate threads.
332 * This is true for read access only with shallow clones, and for both read and
333 * write access with deep clones.
334 * It is the responsibility of the Text Provider to ensure that this thread safety
335 * constraint is met.
336 *
337 * @param dest A UText struct to be filled in with the result of the clone operation,
338 * or NULL if the clone function should heap-allocate a new UText struct.
339 * If non-NULL, must refer to an already existing UText, which will then
340 * be reset to become the clone.
341 * @param src The UText to be cloned.
342 * @param deep TRUE to request a deep clone, FALSE for a shallow clone.
343 * @param readOnly TRUE to request that the cloned UText have read only access to the
344 * underlying text.
345
346 * @param status Errors are returned here. For deep clones, U_UNSUPPORTED_ERROR
347 * will be returned if the text provider is unable to clone the
348 * original text.
349 * @return The newly created clone, or NULL if the clone operation failed.
350 * @stable ICU 3.4
351 */
352U_STABLE UText * U_EXPORT2
353utext_clone(UText *dest, const UText *src, UBool deep, UBool readOnly, UErrorCode *status);
354
355
356/**
357 * Compare two UText objects for equality.
358 * UTexts are equal if they are iterating over the same text, and
359 * have the same iteration position within the text.
360 * If either or both of the parameters are NULL, the comparison is FALSE.
361 *
362 * @param a The first of the two UTexts to compare.
363 * @param b The other UText to be compared.
364 * @return TRUE if the two UTexts are equal.
365 * @stable ICU 3.6
366 */
367U_STABLE UBool U_EXPORT2
368utext_equals(const UText *a, const UText *b);
369
370
371/*****************************************************************************
372 *
373 * Functions to work with the text represented by a UText wrapper
374 *
375 *****************************************************************************/
376
377/**
378 * Get the length of the text. Depending on the characteristics
379 * of the underlying text representation, this may be expensive.
380 * @see utext_isLengthExpensive()
381 *
382 *
383 * @param ut the text to be accessed.
384 * @return the length of the text, expressed in native units.
385 *
386 * @stable ICU 3.4
387 */
388U_STABLE int64_t U_EXPORT2
389utext_nativeLength(UText *ut);
390
391/**
392 * Return TRUE if calculating the length of the text could be expensive.
393 * Finding the length of NUL terminated strings is considered to be expensive.
394 *
395 * Note that the value of this function may change
396 * as the result of other operations on a UText.
397 * Once the length of a string has been discovered, it will no longer
398 * be expensive to report it.
399 *
400 * @param ut the text to be accessed.
401 * @return TRUE if determining the length of the text could be time consuming.
402 * @stable ICU 3.4
403 */
404U_STABLE UBool U_EXPORT2
405utext_isLengthExpensive(const UText *ut);
406
407/**
408 * Returns the code point at the requested index,
409 * or U_SENTINEL (-1) if it is out of bounds.
410 *
411 * If the specified index points to the interior of a multi-unit
412 * character - one of the trail bytes of a UTF-8 sequence, for example -
413 * the complete code point will be returned.
414 *
415 * The iteration position will be set to the start of the returned code point.
416 *
417 * This function is roughly equivalent to the sequence
418 * utext_setNativeIndex(index);
419 * utext_current32();
420 * (There is a subtle difference if the index is out of bounds by being less than zero -
421 * utext_setNativeIndex(negative value) sets the index to zero, after which utext_current()
422 * will return the char at zero. utext_char32At(negative index), on the other hand, will
423 * return the U_SENTINEL value of -1.)
424 *
425 * @param ut the text to be accessed
426 * @param nativeIndex the native index of the character to be accessed. If the index points
427 * to other than the first unit of a multi-unit character, it will be adjusted
428 * to the start of the character.
429 * @return the code point at the specified index.
430 * @stable ICU 3.4
431 */
432U_STABLE UChar32 U_EXPORT2
433utext_char32At(UText *ut, int64_t nativeIndex);
434
435
436/**
437 *
438 * Get the code point at the current iteration position,
439 * or U_SENTINEL (-1) if the iteration has reached the end of
440 * the input text.
441 *
442 * @param ut the text to be accessed.
443 * @return the Unicode code point at the current iterator position.
444 * @stable ICU 3.4
445 */
446U_STABLE UChar32 U_EXPORT2
447utext_current32(UText *ut);
448
449
450/**
451 * Get the code point at the current iteration position of the UText, and
452 * advance the position to the first index following the character.
453 *
454 * If the position is at the end of the text (the index following
455 * the last character, which is also the length of the text),
456 * return U_SENTINEL (-1) and do not advance the index.
457 *
458 * This is a post-increment operation.
459 *
460 * An inline macro version of this function, UTEXT_NEXT32(),
461 * is available for performance critical use.
462 *
463 * @param ut the text to be accessed.
464 * @return the Unicode code point at the iteration position.
465 * @see UTEXT_NEXT32
466 * @stable ICU 3.4
467 */
468U_STABLE UChar32 U_EXPORT2
469utext_next32(UText *ut);
470
471
472/**
473 * Move the iterator position to the character (code point) whose
474 * index precedes the current position, and return that character.
475 * This is a pre-decrement operation.
476 *
477 * If the initial position is at the start of the text (index of 0)
478 * return U_SENTINEL (-1), and leave the position unchanged.
479 *
480 * An inline macro version of this function, UTEXT_PREVIOUS32(),
481 * is available for performance critical use.
482 *
483 * @param ut the text to be accessed.
484 * @return the previous UChar32 code point, or U_SENTINEL (-1)
485 * if the iteration has reached the start of the text.
486 * @see UTEXT_PREVIOUS32
487 * @stable ICU 3.4
488 */
489U_STABLE UChar32 U_EXPORT2
490utext_previous32(UText *ut);
491
492
493/**
494 * Set the iteration index and return the code point at that index.
495 * Leave the iteration index at the start of the following code point.
496 *
497 * This function is the most efficient and convenient way to
498 * begin a forward iteration. The results are identical to the those
499 * from the sequence
500 * \code
501 * utext_setIndex();
502 * utext_next32();
503 * \endcode
504 *
505 * @param ut the text to be accessed.
506 * @param nativeIndex Iteration index, in the native units of the text provider.
507 * @return Code point which starts at or before index,
508 * or U_SENTINEL (-1) if it is out of bounds.
509 * @stable ICU 3.4
510 */
511U_STABLE UChar32 U_EXPORT2
512utext_next32From(UText *ut, int64_t nativeIndex);
513
514
515
516/**
517 * Set the iteration index, and return the code point preceding the
518 * one specified by the initial index. Leave the iteration position
519 * at the start of the returned code point.
520 *
521 * This function is the most efficient and convenient way to
522 * begin a backwards iteration.
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 preceding the one at the initial index,
527 * or U_SENTINEL (-1) if it is out of bounds.
528 *
529 * @stable ICU 3.4
530 */
531U_STABLE UChar32 U_EXPORT2
532utext_previous32From(UText *ut, int64_t nativeIndex);
533
534/**
535 * Get the current iterator position, which can range from 0 to
536 * the length of the text.
537 * The position is a native index into the input text, in whatever format it
538 * may have (possibly UTF-8 for example), and may not always be the same as
539 * the corresponding UChar (UTF-16) index.
540 * The returned position will always be aligned to a code point boundary.
541 *
542 * @param ut the text to be accessed.
543 * @return the current index position, in the native units of the text provider.
544 * @stable ICU 3.4
545 */
546U_STABLE int64_t U_EXPORT2
547utext_getNativeIndex(const UText *ut);
548
549/**
550 * Set the current iteration position to the nearest code point
551 * boundary at or preceding the specified index.
552 * The index is in the native units of the original input text.
553 * If the index is out of range, it will be pinned to be within
554 * the range of the input text.
555 * <p>
556 * It will usually be more efficient to begin an iteration
557 * using the functions utext_next32From() or utext_previous32From()
558 * rather than setIndex().
559 * <p>
560 * Moving the index position to an adjacent character is best done
561 * with utext_next32(), utext_previous32() or utext_moveIndex32().
562 * Attempting to do direct arithmetic on the index position is
563 * complicated by the fact that the size (in native units) of a
564 * character depends on the underlying representation of the character
565 * (UTF-8, UTF-16, UTF-32, arbitrary codepage), and is not
566 * easily knowable.
567 *
568 * @param ut the text to be accessed.
569 * @param nativeIndex the native unit index of the new iteration position.
570 * @stable ICU 3.4
571 */
572U_STABLE void U_EXPORT2
573utext_setNativeIndex(UText *ut, int64_t nativeIndex);
574
575/**
576 * Move the iterator position by delta code points. The number of code points
577 * is a signed number; a negative delta will move the iterator backwards,
578 * towards the start of the text.
579 * <p>
580 * The index is moved by <code>delta</code> code points
581 * forward or backward, but no further backward than to 0 and
582 * no further forward than to utext_nativeLength().
583 * The resulting index value will be in between 0 and length, inclusive.
584 *
585 * @param ut the text to be accessed.
586 * @param delta the signed number of code points to move the iteration position.
587 * @return TRUE if the position could be moved the requested number of positions while
588 * staying within the range [0 - text length].
589 * @stable ICU 3.4
590 */
591U_STABLE UBool U_EXPORT2
592utext_moveIndex32(UText *ut, int32_t delta);
593
594/**
595 * Get the native index of the character preceding the current position.
596 * If the iteration position is already at the start of the text, zero
597 * is returned.
598 * The value returned is the same as that obtained from the following sequence,
599 * but without the side effect of changing the iteration position.
600 *
601 * \code
602 * UText *ut = whatever;
603 * ...
604 * utext_previous(ut)
605 * utext_getNativeIndex(ut);
606 * \endcode
607 *
608 * This function is most useful during forwards iteration, where it will get the
609 * native index of the character most recently returned from utext_next().
610 *
611 * @param ut the text to be accessed
612 * @return the native index of the character preceding the current index position,
613 * or zero if the current position is at the start of the text.
614 * @stable ICU 3.6
615 */
616U_STABLE int64_t U_EXPORT2
617utext_getPreviousNativeIndex(UText *ut);
618
619
620/**
621 *
622 * Extract text from a UText into a UChar buffer. The range of text to be extracted
623 * is specified in the native indices of the UText provider. These may not necessarily
624 * be UTF-16 indices.
625 * <p>
626 * The size (number of 16 bit UChars) of the data to be extracted is returned. The
627 * full number of UChars is returned, even when the extracted text is truncated
628 * because the specified buffer size is too small.
629 * <p>
630 * The extracted string will (if you are a user) / must (if you are a text provider)
631 * be NUL-terminated if there is sufficient space in the destination buffer. This
632 * terminating NUL is not included in the returned length.
633 * <p>
634 * The iteration index is left at the position following the last extracted character.
635 *
636 * @param ut the UText from which to extract data.
637 * @param nativeStart the native index of the first character to extract.\
638 * If the specified index is out of range,
639 * it will be pinned to be within 0 <= index <= textLength
640 * @param nativeLimit the native string index of the position following the last
641 * character to extract. If the specified index is out of range,
642 * it will be pinned to be within 0 <= index <= textLength.
643 * nativeLimit must be >= nativeStart.
644 * @param dest the UChar (UTF-16) buffer into which the extracted text is placed
645 * @param destCapacity The size, in UChars, of the destination buffer. May be zero
646 * for precomputing the required size.
647 * @param status receives any error status.
648 * U_BUFFER_OVERFLOW_ERROR: the extracted text was truncated because the
649 * buffer was too small. Returns number of UChars for preflighting.
650 * @return Number of UChars in the data to be extracted. Does not include a trailing NUL.
651 *
652 * @stable ICU 3.4
653 */
654U_STABLE int32_t U_EXPORT2
655utext_extract(UText *ut,
656 int64_t nativeStart, int64_t nativeLimit,
657 UChar *dest, int32_t destCapacity,
658 UErrorCode *status);
659
660
661
662/************************************************************************************
663 *
664 * #define inline versions of selected performance-critical text access functions
665 * Caution: do not use auto increment++ or decrement-- expressions
666 * as parameters to these macros.
667 *
668 * For most use, where there is no extreme performance constraint, the
669 * normal, non-inline functions are a better choice. The resulting code
670 * will be smaller, and, if the need ever arises, easier to debug.
671 *
672 * These are implemented as #defines rather than real functions
673 * because there is no fully portable way to do inline functions in plain C.
674 *
675 ************************************************************************************/
676
677#ifndef U_HIDE_INTERNAL_API
678/**
679 * inline version of utext_current32(), for performance-critical situations.
680 *
681 * Get the code point at the current iteration position of the UText.
682 * Returns U_SENTINEL (-1) if the position is at the end of the
683 * text.
684 *
685 * @internal ICU 4.4 technology preview
686 */
687#define UTEXT_CURRENT32(ut) \
688 ((ut)->chunkOffset < (ut)->chunkLength && ((ut)->chunkContents)[(ut)->chunkOffset]<0xd800 ? \
689 ((ut)->chunkContents)[((ut)->chunkOffset)] : utext_current32(ut))
690#endif /* U_HIDE_INTERNAL_API */
691
692/**
693 * inline version of utext_next32(), for performance-critical situations.
694 *
695 * Get the code point at the current iteration position of the UText, and
696 * advance the position to the first index following the character.
697 * This is a post-increment operation.
698 * Returns U_SENTINEL (-1) if the position is at the end of the
699 * text.
700 *
701 * @stable ICU 3.4
702 */
703#define UTEXT_NEXT32(ut) \
704 ((ut)->chunkOffset < (ut)->chunkLength && ((ut)->chunkContents)[(ut)->chunkOffset]<0xd800 ? \
705 ((ut)->chunkContents)[((ut)->chunkOffset)++] : utext_next32(ut))
706
707/**
708 * inline version of utext_previous32(), for performance-critical situations.
709 *
710 * Move the iterator position to the character (code point) whose
711 * index precedes the current position, and return that character.
712 * This is a pre-decrement operation.
713 * Returns U_SENTINEL (-1) if the position is at the start of the text.
714 *
715 * @stable ICU 3.4
716 */
717#define UTEXT_PREVIOUS32(ut) \
718 ((ut)->chunkOffset > 0 && \
719 (ut)->chunkContents[(ut)->chunkOffset-1] < 0xd800 ? \
720 (ut)->chunkContents[--((ut)->chunkOffset)] : utext_previous32(ut))
721
722/**
723 * inline version of utext_getNativeIndex(), for performance-critical situations.
724 *
725 * Get the current iterator position, which can range from 0 to
726 * the length of the text.
727 * The position is a native index into the input text, in whatever format it
728 * may have (possibly UTF-8 for example), and may not always be the same as
729 * the corresponding UChar (UTF-16) index.
730 * The returned position will always be aligned to a code point boundary.
731 *
732 * @stable ICU 3.6
733 */
734#define UTEXT_GETNATIVEINDEX(ut) \
735 ((ut)->chunkOffset <= (ut)->nativeIndexingLimit? \
736 (ut)->chunkNativeStart+(ut)->chunkOffset : \
737 (ut)->pFuncs->mapOffsetToNative(ut))
738
739/**
740 * inline version of utext_setNativeIndex(), for performance-critical situations.
741 *
742 * Set the current iteration position to the nearest code point
743 * boundary at or preceding the specified index.
744 * The index is in the native units of the original input text.
745 * If the index is out of range, it will be pinned to be within
746 * the range of the input text.
747 *
748 * @stable ICU 3.8
749 */
750#define UTEXT_SETNATIVEINDEX(ut, ix) UPRV_BLOCK_MACRO_BEGIN { \
751 int64_t __offset = (ix) - (ut)->chunkNativeStart; \
752 if (__offset>=0 && __offset<(int64_t)(ut)->nativeIndexingLimit && (ut)->chunkContents[__offset]<0xdc00) { \
753 (ut)->chunkOffset=(int32_t)__offset; \
754 } else { \
755 utext_setNativeIndex((ut), (ix)); \
756 } \
757} UPRV_BLOCK_MACRO_END
758
759
760
761/************************************************************************************
762 *
763 * Functions related to writing or modifying the text.
764 * These will work only with modifiable UTexts. Attempting to
765 * modify a read-only UText will return an error status.
766 *
767 ************************************************************************************/
768
769
770/**
771 * Return TRUE if the text can be written (modified) with utext_replace() or
772 * utext_copy(). For the text to be writable, the text provider must
773 * be of a type that supports writing and the UText must not be frozen.
774 *
775 * Attempting to modify text when utext_isWriteable() is FALSE will fail -
776 * the text will not be modified, and an error will be returned from the function
777 * that attempted the modification.
778 *
779 * @param ut the UText to be tested.
780 * @return TRUE if the text is modifiable.
781 *
782 * @see utext_freeze()
783 * @see utext_replace()
784 * @see utext_copy()
785 * @stable ICU 3.4
786 *
787 */
788U_STABLE UBool U_EXPORT2
789utext_isWritable(const UText *ut);
790
791
792/**
793 * Test whether there is meta data associated with the text.
794 * @see Replaceable::hasMetaData()
795 *
796 * @param ut The UText to be tested
797 * @return TRUE if the underlying text includes meta data.
798 * @stable ICU 3.4
799 */
800U_STABLE UBool U_EXPORT2
801utext_hasMetaData(const UText *ut);
802
803
804/**
805 * Replace a range of the original text with a replacement text.
806 *
807 * Leaves the current iteration position at the position following the
808 * newly inserted replacement text.
809 *
810 * This function is only available on UText types that support writing,
811 * that is, ones where utext_isWritable() returns TRUE.
812 *
813 * When using this function, there should be only a single UText opened onto the
814 * underlying native text string. Behavior after a replace operation
815 * on a UText is undefined for any other additional UTexts that refer to the
816 * modified string.
817 *
818 * @param ut the UText representing the text to be operated on.
819 * @param nativeStart the native index of the start of the region to be replaced
820 * @param nativeLimit the native index of the character following the region to be replaced.
821 * @param replacementText pointer to the replacement text
822 * @param replacementLength length of the replacement text, or -1 if the text is NUL terminated.
823 * @param status receives any error status. Possible errors include
824 * U_NO_WRITE_PERMISSION
825 *
826 * @return The signed number of (native) storage units by which
827 * the length of the text expanded or contracted.
828 *
829 * @stable ICU 3.4
830 */
831U_STABLE int32_t U_EXPORT2
832utext_replace(UText *ut,
833 int64_t nativeStart, int64_t nativeLimit,
834 const UChar *replacementText, int32_t replacementLength,
835 UErrorCode *status);
836
837
838
839/**
840 *
841 * Copy or move a substring from one position to another within the text,
842 * while retaining any metadata associated with the text.
843 * This function is used to duplicate or reorder substrings.
844 * The destination index must not overlap the source range.
845 *
846 * The text to be copied or moved is inserted at destIndex;
847 * it does not replace or overwrite any existing text.
848 *
849 * The iteration position is left following the newly inserted text
850 * at the destination position.
851 *
852 * This function is only available on UText types that support writing,
853 * that is, ones where utext_isWritable() returns TRUE.
854 *
855 * When using this function, there should be only a single UText opened onto the
856 * underlying native text string. Behavior after a copy operation
857 * on a UText is undefined in any other additional UTexts that refer to the
858 * modified string.
859 *
860 * @param ut The UText representing the text to be operated on.
861 * @param nativeStart The native index of the start of the region to be copied or moved
862 * @param nativeLimit The native index of the character position following the region
863 * to be copied.
864 * @param destIndex The native destination index to which the source substring is
865 * copied or moved.
866 * @param move If TRUE, then the substring is moved, not copied/duplicated.
867 * @param status receives any error status. Possible errors include U_NO_WRITE_PERMISSION
868 *
869 * @stable ICU 3.4
870 */
871U_STABLE void U_EXPORT2
872utext_copy(UText *ut,
873 int64_t nativeStart, int64_t nativeLimit,
874 int64_t destIndex,
875 UBool move,
876 UErrorCode *status);
877
878
879/**
880 * <p>
881 * Freeze a UText. This prevents any modification to the underlying text itself
882 * by means of functions operating on this UText.
883 * </p>
884 * <p>
885 * Once frozen, a UText can not be unfrozen. The intent is to ensure
886 * that a the text underlying a frozen UText wrapper cannot be modified via that UText.
887 * </p>
888 * <p>
889 * Caution: freezing a UText will disable changes made via the specific
890 * frozen UText wrapper only; it will not have any effect on the ability to
891 * directly modify the text by bypassing the UText. Any such backdoor modifications
892 * are always an error while UText access is occurring because the underlying
893 * text can get out of sync with UText's buffering.
894 * </p>
895 *
896 * @param ut The UText to be frozen.
897 * @see utext_isWritable()
898 * @stable ICU 3.6
899 */
900U_STABLE void U_EXPORT2
901utext_freeze(UText *ut);
902
903
904/**
905 * UText provider properties (bit field indexes).
906 *
907 * @see UText
908 * @stable ICU 3.4
909 */
910enum {
911 /**
912 * It is potentially time consuming for the provider to determine the length of the text.
913 * @stable ICU 3.4
914 */
915 UTEXT_PROVIDER_LENGTH_IS_EXPENSIVE = 1,
916 /**
917 * Text chunks remain valid and usable until the text object is modified or
918 * deleted, not just until the next time the access() function is called
919 * (which is the default).
920 * @stable ICU 3.4
921 */
922 UTEXT_PROVIDER_STABLE_CHUNKS = 2,
923 /**
924 * The provider supports modifying the text via the replace() and copy()
925 * functions.
926 * @see Replaceable
927 * @stable ICU 3.4
928 */
929 UTEXT_PROVIDER_WRITABLE = 3,
930 /**
931 * There is meta data associated with the text.
932 * @see Replaceable::hasMetaData()
933 * @stable ICU 3.4
934 */
935 UTEXT_PROVIDER_HAS_META_DATA = 4,
936 /**
937 * Text provider owns the text storage.
938 * Generally occurs as the result of a deep clone of the UText.
939 * When closing the UText, the associated text must
940 * also be closed/deleted/freed/ whatever is appropriate.
941 * @stable ICU 3.6
942 */
943 UTEXT_PROVIDER_OWNS_TEXT = 5
944};
945
946/**
947 * Function type declaration for UText.clone().
948 *
949 * clone a UText. Much like opening a UText where the source text is itself
950 * another UText.
951 *
952 * A deep clone will copy both the UText data structures and the underlying text.
953 * The original and cloned UText will operate completely independently; modifications
954 * made to the text in one will not effect the other. Text providers are not
955 * required to support deep clones. The user of clone() must check the status return
956 * and be prepared to handle failures.
957 *
958 * A shallow clone replicates only the UText data structures; it does not make
959 * a copy of the underlying text. Shallow clones can be used as an efficient way to
960 * have multiple iterators active in a single text string that is not being
961 * modified.
962 *
963 * A shallow clone operation must not fail except for truly exceptional conditions such
964 * as memory allocation failures.
965 *
966 * A UText and its clone may be safely concurrently accessed by separate threads.
967 * This is true for both shallow and deep clones.
968 * It is the responsibility of the Text Provider to ensure that this thread safety
969 * constraint is met.
970
971 *
972 * @param dest A UText struct to be filled in with the result of the clone operation,
973 * or NULL if the clone function should heap-allocate a new UText struct.
974 * @param src The UText to be cloned.
975 * @param deep TRUE to request a deep clone, FALSE for a shallow clone.
976 * @param status Errors are returned here. For deep clones, U_UNSUPPORTED_ERROR
977 * should be returned if the text provider is unable to clone the
978 * original text.
979 * @return The newly created clone, or NULL if the clone operation failed.
980 *
981 * @stable ICU 3.4
982 */
983typedef UText * U_CALLCONV
984UTextClone(UText *dest, const UText *src, UBool deep, UErrorCode *status);
985
986
987/**
988 * Function type declaration for UText.nativeLength().
989 *
990 * @param ut the UText to get the length of.
991 * @return the length, in the native units of the original text string.
992 * @see UText
993 * @stable ICU 3.4
994 */
995typedef int64_t U_CALLCONV
996UTextNativeLength(UText *ut);
997
998/**
999 * Function type declaration for UText.access(). Get the description of the text chunk
1000 * containing the text at a requested native index. The UText's iteration
1001 * position will be left at the requested index. If the index is out
1002 * of bounds, the iteration position will be left at the start or end
1003 * of the string, as appropriate.
1004 *
1005 * Chunks must begin and end on code point boundaries. A single code point
1006 * comprised of multiple storage units must never span a chunk boundary.
1007 *
1008 *
1009 * @param ut the UText being accessed.
1010 * @param nativeIndex Requested index of the text to be accessed.
1011 * @param forward If TRUE, then the returned chunk must contain text
1012 * starting from the index, so that start<=index<limit.
1013 * If FALSE, then the returned chunk must contain text
1014 * before the index, so that start<index<=limit.
1015 * @return True if the requested index could be accessed. The chunk
1016 * will contain the requested text.
1017 * False value if a chunk cannot be accessed
1018 * (the requested index is out of bounds).
1019 *
1020 * @see UText
1021 * @stable ICU 3.4
1022 */
1023typedef UBool U_CALLCONV
1024UTextAccess(UText *ut, int64_t nativeIndex, UBool forward);
1025
1026/**
1027 * Function type declaration for UText.extract().
1028 *
1029 * Extract text from a UText into a UChar buffer. The range of text to be extracted
1030 * is specified in the native indices of the UText provider. These may not necessarily
1031 * be UTF-16 indices.
1032 * <p>
1033 * The size (number of 16 bit UChars) in the data to be extracted is returned. The
1034 * full amount is returned, even when the specified buffer size is smaller.
1035 * <p>
1036 * The extracted string will (if you are a user) / must (if you are a text provider)
1037 * be NUL-terminated if there is sufficient space in the destination buffer.
1038 *
1039 * @param ut the UText from which to extract data.
1040 * @param nativeStart the native index of the first character to extract.
1041 * @param nativeLimit the native string index of the position following the last
1042 * character to extract.
1043 * @param dest the UChar (UTF-16) buffer into which the extracted text is placed
1044 * @param destCapacity The size, in UChars, of the destination buffer. May be zero
1045 * for precomputing the required size.
1046 * @param status receives any error status.
1047 * If U_BUFFER_OVERFLOW_ERROR: Returns number of UChars for
1048 * preflighting.
1049 * @return Number of UChars in the data. Does not include a trailing NUL.
1050 *
1051 * @stable ICU 3.4
1052 */
1053typedef int32_t U_CALLCONV
1054UTextExtract(UText *ut,
1055 int64_t nativeStart, int64_t nativeLimit,
1056 UChar *dest, int32_t destCapacity,
1057 UErrorCode *status);
1058
1059/**
1060 * Function type declaration for UText.replace().
1061 *
1062 * Replace a range of the original text with a replacement text.
1063 *
1064 * Leaves the current iteration position at the position following the
1065 * newly inserted replacement text.
1066 *
1067 * This function need only be implemented on UText types that support writing.
1068 *
1069 * When using this function, there should be only a single UText opened onto the
1070 * underlying native text string. The function is responsible for updating the
1071 * text chunk within the UText to reflect the updated iteration position,
1072 * taking into account any changes to the underlying string's structure caused
1073 * by the replace operation.
1074 *
1075 * @param ut the UText representing the text to be operated on.
1076 * @param nativeStart the index of the start of the region to be replaced
1077 * @param nativeLimit the index of the character following the region to be replaced.
1078 * @param replacementText pointer to the replacement text
1079 * @param replacmentLength length of the replacement text in UChars, or -1 if the text is NUL terminated.
1080 * @param status receives any error status. Possible errors include
1081 * U_NO_WRITE_PERMISSION
1082 *
1083 * @return The signed number of (native) storage units by which
1084 * the length of the text expanded or contracted.
1085 *
1086 * @stable ICU 3.4
1087 */
1088typedef int32_t U_CALLCONV
1089UTextReplace(UText *ut,
1090 int64_t nativeStart, int64_t nativeLimit,
1091 const UChar *replacementText, int32_t replacmentLength,
1092 UErrorCode *status);
1093
1094/**
1095 * Function type declaration for UText.copy().
1096 *
1097 * Copy or move a substring from one position to another within the text,
1098 * while retaining any metadata associated with the text.
1099 * This function is used to duplicate or reorder substrings.
1100 * The destination index must not overlap the source range.
1101 *
1102 * The text to be copied or moved is inserted at destIndex;
1103 * it does not replace or overwrite any existing text.
1104 *
1105 * This function need only be implemented for UText types that support writing.
1106 *
1107 * When using this function, there should be only a single UText opened onto the
1108 * underlying native text string. The function is responsible for updating the
1109 * text chunk within the UText to reflect the updated iteration position,
1110 * taking into account any changes to the underlying string's structure caused
1111 * by the replace operation.
1112 *
1113 * @param ut The UText representing the text to be operated on.
1114 * @param nativeStart The index of the start of the region to be copied or moved
1115 * @param nativeLimit The index of the character following the region to be replaced.
1116 * @param nativeDest The destination index to which the source substring is copied or moved.
1117 * @param move If TRUE, then the substring is moved, not copied/duplicated.
1118 * @param status receives any error status. Possible errors include U_NO_WRITE_PERMISSION
1119 *
1120 * @stable ICU 3.4
1121 */
1122typedef void U_CALLCONV
1123UTextCopy(UText *ut,
1124 int64_t nativeStart, int64_t nativeLimit,
1125 int64_t nativeDest,
1126 UBool move,
1127 UErrorCode *status);
1128
1129/**
1130 * Function type declaration for UText.mapOffsetToNative().
1131 * Map from the current UChar offset within the current text chunk to
1132 * the corresponding native index in the original source text.
1133 *
1134 * This is required only for text providers that do not use native UTF-16 indexes.
1135 *
1136 * @param ut the UText.
1137 * @return Absolute (native) index corresponding to chunkOffset in the current chunk.
1138 * The returned native index should always be to a code point boundary.
1139 *
1140 * @stable ICU 3.4
1141 */
1142typedef int64_t U_CALLCONV
1143UTextMapOffsetToNative(const UText *ut);
1144
1145/**
1146 * Function type declaration for UText.mapIndexToUTF16().
1147 * Map from a native index to a UChar offset within a text chunk.
1148 * Behavior is undefined if the native index does not fall within the
1149 * current chunk.
1150 *
1151 * This function is required only for text providers that do not use native UTF-16 indexes.
1152 *
1153 * @param ut The UText containing the text chunk.
1154 * @param nativeIndex Absolute (native) text index, chunk->start<=index<=chunk->limit.
1155 * @return Chunk-relative UTF-16 offset corresponding to the specified native
1156 * index.
1157 *
1158 * @stable ICU 3.4
1159 */
1160typedef int32_t U_CALLCONV
1161UTextMapNativeIndexToUTF16(const UText *ut, int64_t nativeIndex);
1162
1163
1164/**
1165 * Function type declaration for UText.utextClose().
1166 *
1167 * A Text Provider close function is only required for provider types that make
1168 * allocations in their open function (or other functions) that must be
1169 * cleaned when the UText is closed.
1170 *
1171 * The allocation of the UText struct itself and any "extra" storage
1172 * associated with the UText is handled by the common UText implementation
1173 * and does not require provider specific cleanup in a close function.
1174 *
1175 * Most UText provider implementations do not need to implement this function.
1176 *
1177 * @param ut A UText object to be closed.
1178 *
1179 * @stable ICU 3.4
1180 */
1181typedef void U_CALLCONV
1182UTextClose(UText *ut);
1183
1184
1185/**
1186 * (public) Function dispatch table for UText.
1187 * Conceptually very much like a C++ Virtual Function Table.
1188 * This struct defines the organization of the table.
1189 * Each text provider implementation must provide an
1190 * actual table that is initialized with the appropriate functions
1191 * for the type of text being handled.
1192 * @stable ICU 3.6
1193 */
1194struct UTextFuncs {
1195 /**
1196 * (public) Function table size, sizeof(UTextFuncs)
1197 * Intended for use should the table grow to accommodate added
1198 * functions in the future, to allow tests for older format
1199 * function tables that do not contain the extensions.
1200 *