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// © 2016 and later: Unicode, Inc. and others. // License & terms of use: http://www.unicode.org/copyright.html /* ******************************************************************************* * * Copyright (C) 2004-2012, International Business Machines * Corporation and others. All Rights Reserved. * ******************************************************************************* * file name: utext.h * encoding: UTF-8 * tab size: 8 (not used) * indentation:4 * * created on: 2004oct06 * created by: Markus W. Scherer */ #ifndef __UTEXT_H__ #define __UTEXT_H__ /** * \file * \brief C API: Abstract Unicode Text API * * The Text Access API provides a means to allow text that is stored in alternative * formats to work with ICU services. ICU normally operates on text that is * stored in UTF-16 format, in (UChar *) arrays for the C APIs or as type * UnicodeString for C++ APIs. * * ICU Text Access allows other formats, such as UTF-8 or non-contiguous * UTF-16 strings, to be placed in a UText wrapper and then passed to ICU services. * * There are three general classes of usage for UText: * * Application Level Use. This is the simplest usage - applications would * use one of the utext_open() functions on their input text, and pass * the resulting UText to the desired ICU service. * * Second is usage in ICU Services, such as break iteration, that will need to * operate on input presented to them as a UText. These implementations * will need to use the iteration and related UText functions to gain * access to the actual text. * * The third class of UText users are "text providers." These are the * UText implementations for the various text storage formats. An application * or system with a unique text storage format can implement a set of * UText provider functions for that format, which will then allow * ICU services to operate on that format. * * * <em>Iterating over text</em> * * Here is sample code for a forward iteration over the contents of a UText * * \code * UChar32 c; * UText *ut = whatever(); * * for (c=utext_next32From(ut, 0); c>=0; c=utext_next32(ut)) { * // do whatever with the codepoint c here. * } * \endcode * * And here is similar code to iterate in the reverse direction, from the end * of the text towards the beginning. * * \code * UChar32 c; * UText *ut = whatever(); * int textLength = utext_nativeLength(ut); * for (c=utext_previous32From(ut, textLength); c>=0; c=utext_previous32(ut)) { * // do whatever with the codepoint c here. * } * \endcode * * <em>Characters and Indexing</em> * * Indexing into text by UText functions is nearly always in terms of the native * indexing of the underlying text storage. The storage format could be UTF-8 * or UTF-32, for example. When coding to the UText access API, no assumptions * can be made regarding the size of characters, or how far an index * may move when iterating between characters. * * All indices supplied to UText functions are pinned to the length of the * text. An out-of-bounds index is not considered to be an error, but is * adjusted to be in the range 0 <= index <= length of input text. * * * When an index position is returned from a UText function, it will be * a native index to the underlying text. In the case of multi-unit characters, * it will always refer to the first position of the character, * never to the interior. This is essentially the same thing as saying that * a returned index will always point to a boundary between characters. * * When a native index is supplied to a UText function, all indices that * refer to any part of a multi-unit character representation are considered * to be equivalent. In the case of multi-unit characters, an incoming index * will be logically normalized to refer to the start of the character. * * It is possible to test whether a native index is on a code point boundary * by doing a utext_setNativeIndex() followed by a utext_getNativeIndex(). * If the index is returned unchanged, it was on a code point boundary. If * an adjusted index is returned, the original index referred to the * interior of a character. * * <em>Conventions for calling UText functions</em> * * Most UText access functions have as their first parameter a (UText *) pointer, * which specifies the UText to be used. Unless otherwise noted, the * pointer must refer to a valid, open UText. Attempting to * use a closed UText or passing a NULL pointer is a programming error and * will produce undefined results or NULL pointer exceptions. * * The UText_Open family of functions can either open an existing (closed) * UText, or heap allocate a new UText. Here is sample code for creating * a stack-allocated UText. * * \code * char *s = whatever(); // A utf-8 string * U_ErrorCode status = U_ZERO_ERROR; * UText ut = UTEXT_INITIALIZER; * utext_openUTF8(ut, s, -1, &status); * if (U_FAILURE(status)) { * // error handling * } else { * // work with the UText * } * \endcode * * Any existing UText passed to an open function _must_ have been initialized, * either by the UTEXT_INITIALIZER, or by having been originally heap-allocated * by an open function. Passing NULL will cause the open function to * heap-allocate and fully initialize a new UText. * */ #include "unicode/utypes.h" #include "unicode/uchar.h" #if U_SHOW_CPLUSPLUS_API #include "unicode/localpointer.h" #include "unicode/rep.h" #include "unicode/unistr.h" #include "unicode/chariter.h" #endif U_CDECL_BEGIN struct UText; typedef struct UText UText; /**< C typedef for struct UText. @stable ICU 3.6 */ /*************************************************************************************** * * C Functions for creating UText wrappers around various kinds of text strings. * ****************************************************************************************/ /** * Close function for UText instances. * Cleans up, releases any resources being held by an open UText. * <p> * If the UText was originally allocated by one of the utext_open functions, * the storage associated with the utext will also be freed. * If the UText storage originated with the application, as it would with * a local or static instance, the storage will not be deleted. * * An open UText can be reset to refer to new string by using one of the utext_open() * functions without first closing the UText. * * @param ut The UText to be closed. * @return NULL if the UText struct was deleted by the close. If the UText struct * was originally provided by the caller to the open function, it is * returned by this function, and may be safely used again in * a subsequent utext_open. * * @stable ICU 3.4 */ U_STABLE UText * U_EXPORT2 utext_close(UText *ut); #if U_SHOW_CPLUSPLUS_API U_NAMESPACE_BEGIN /** * \class LocalUTextPointer * "Smart pointer" class, closes a UText via utext_close(). * For most methods see the LocalPointerBase base class. * * @see LocalPointerBase * @see LocalPointer * @stable ICU 4.4 */ U_DEFINE_LOCAL_OPEN_POINTER(LocalUTextPointer, UText, utext_close); U_NAMESPACE_END #endif /** * Open a read-only UText implementation for UTF-8 strings. * * \htmlonly * Any invalid UTF-8 in the input will be handled in this way: * a sequence of bytes that has the form of a truncated, but otherwise valid, * UTF-8 sequence will be replaced by a single unicode replacement character, \uFFFD. * Any other illegal bytes will each be replaced by a \uFFFD. * \endhtmlonly * * @param ut Pointer to a UText struct. If NULL, a new UText will be created. * If non-NULL, must refer to an initialized UText struct, which will then * be reset to reference the specified UTF-8 string. * @param s A UTF-8 string. Must not be NULL. * @param length The length of the UTF-8 string in bytes, or -1 if the string is * zero terminated. * @param status Errors are returned here. * @return A pointer to the UText. If a pre-allocated UText was provided, it * will always be used and returned. * @stable ICU 3.4 */ U_STABLE UText * U_EXPORT2 utext_openUTF8(UText *ut, const char *s, int64_t length, UErrorCode *status); /** * Open a read-only UText for UChar * string. * * @param ut Pointer to a UText struct. If NULL, a new UText will be created. * If non-NULL, must refer to an initialized UText struct, which will then * be reset to reference the specified UChar string. * @param s A UChar (UTF-16) string * @param length The number of UChars in the input string, or -1 if the string is * zero terminated. * @param status Errors are returned here. * @return A pointer to the UText. If a pre-allocated UText was provided, it * will always be used and returned. * @stable ICU 3.4 */ U_STABLE UText * U_EXPORT2 utext_openUChars(UText *ut, const UChar *s, int64_t length, UErrorCode *status); #if U_SHOW_CPLUSPLUS_API /** * Open a writable UText for a non-const UnicodeString. * * @param ut Pointer to a UText struct. If NULL, a new UText will be created. * If non-NULL, must refer to an initialized UText struct, which will then * be reset to reference the specified input string. * @param s A UnicodeString. * @param status Errors are returned here. * @return Pointer to the UText. If a UText was supplied as input, this * will always be used and returned. * @stable ICU 3.4 */ U_STABLE UText * U_EXPORT2 utext_openUnicodeString(UText *ut, icu::UnicodeString *s, UErrorCode *status); /** * Open a UText for a const UnicodeString. The resulting UText will not be writable. * * @param ut Pointer to a UText struct. If NULL, a new UText will be created. * If non-NULL, must refer to an initialized UText struct, which will then * be reset to reference the specified input string. * @param s A const UnicodeString to be wrapped. * @param status Errors are returned here. * @return Pointer to the UText. If a UText was supplied as input, this * will always be used and returned. * @stable ICU 3.4 */ U_STABLE UText * U_EXPORT2 utext_openConstUnicodeString(UText *ut, const icu::UnicodeString *s, UErrorCode *status); /** * Open a writable UText implementation for an ICU Replaceable object. * @param ut Pointer to a UText struct. If NULL, a new UText will be created. * If non-NULL, must refer to an already existing UText, which will then * be reset to reference the specified replaceable text. * @param rep A Replaceable text object. * @param status Errors are returned here. * @return Pointer to the UText. If a UText was supplied as input, this * will always be used and returned. * @see Replaceable * @stable ICU 3.4 */ U_STABLE UText * U_EXPORT2 utext_openReplaceable(UText *ut, icu::Replaceable *rep, UErrorCode *status); /** * Open a UText implementation over an ICU CharacterIterator. * @param ut Pointer to a UText struct. If NULL, a new UText will be created. * If non-NULL, must refer to an already existing UText, which will then * be reset to reference the specified replaceable text. * @param ci A Character Iterator. * @param status Errors are returned here. * @return Pointer to the UText. If a UText was supplied as input, this * will always be used and returned. * @see Replaceable * @stable ICU 3.4 */ U_STABLE UText * U_EXPORT2 utext_openCharacterIterator(UText *ut, icu::CharacterIterator *ci, UErrorCode *status); #endif /** * Clone a UText. This is much like opening a UText where the source text is itself * another UText. * * A deep clone will copy both the UText data structures and the underlying text. * The original and cloned UText will operate completely independently; modifications * made to the text in one will not affect the other. Text providers are not * required to support deep clones. The user of clone() must check the status return * and be prepared to handle failures. * * The standard UText implementations for UTF8, UChar *, UnicodeString and * Replaceable all support deep cloning. * * The UText returned from a deep clone will be writable, assuming that the text * provider is able to support writing, even if the source UText had been made * non-writable by means of UText_freeze(). * * A shallow clone replicates only the UText data structures; it does not make * a copy of the underlying text. Shallow clones can be used as an efficient way to * have multiple iterators active in a single text string that is not being * modified. * * A shallow clone operation will not fail, barring truly exceptional conditions such * as memory allocation failures. * * Shallow UText clones should be avoided if the UText functions that modify the * text are expected to be used, either on the original or the cloned UText. * Any such modifications can cause unpredictable behavior. Read Only * shallow clones provide some protection against errors of this type by * disabling text modification via the cloned UText. * * A shallow clone made with the readOnly parameter == FALSE will preserve the * utext_isWritable() state of the source object. Note, however, that * write operations must be avoided while more than one UText exists that refer * to the same underlying text. * * A UText and its clone may be safely concurrently accessed by separate threads. * This is true for read access only with shallow clones, and for both read and * write access with deep clones. * It is the responsibility of the Text Provider to ensure that this thread safety * constraint is met. * * @param dest A UText struct to be filled in with the result of the clone operation, * or NULL if the clone function should heap-allocate a new UText struct. * If non-NULL, must refer to an already existing UText, which will then * be reset to become the clone. * @param src The UText to be cloned. * @param deep TRUE to request a deep clone, FALSE for a shallow clone. * @param readOnly TRUE to request that the cloned UText have read only access to the * underlying text. * @param status Errors are returned here. For deep clones, U_UNSUPPORTED_ERROR * will be returned if the text provider is unable to clone the * original text. * @return The newly created clone, or NULL if the clone operation failed. * @stable ICU 3.4 */ U_STABLE UText * U_EXPORT2 utext_clone(UText *dest, const UText *src, UBool deep, UBool readOnly, UErrorCode *status); /** * Compare two UText objects for equality. * UTexts are equal if they are iterating over the same text, and * have the same iteration position within the text. * If either or both of the parameters are NULL, the comparison is FALSE. * * @param a The first of the two UTexts to compare. * @param b The other UText to be compared. * @return TRUE if the two UTexts are equal. * @stable ICU 3.6 */ U_STABLE UBool U_EXPORT2 utext_equals(const UText *a, const UText *b); /***************************************************************************** * * Functions to work with the text represented by a UText wrapper * *****************************************************************************/ /** * Get the length of the text. Depending on the characteristics * of the underlying text representation, this may be expensive. * @see utext_isLengthExpensive() * * * @param ut the text to be accessed. * @return the length of the text, expressed in native units. * * @stable ICU 3.4 */ U_STABLE int64_t U_EXPORT2 utext_nativeLength(UText *ut); /** * Return TRUE if calculating the length of the text could be expensive. * Finding the length of NUL terminated strings is considered to be expensive. * * Note that the value of this function may change * as the result of other operations on a UText. * Once the length of a string has been discovered, it will no longer * be expensive to report it. * * @param ut the text to be accessed. * @return TRUE if determining the length of the text could be time consuming. * @stable ICU 3.4 */ U_STABLE UBool U_EXPORT2 utext_isLengthExpensive(const UText *ut); /** * Returns the code point at the requested index, * or U_SENTINEL (-1) if it is out of bounds. * * If the specified index points to the interior of a multi-unit * character - one of the trail bytes of a UTF-8 sequence, for example - * the complete code point will be returned. * * The iteration position will be set to the start of the returned code point. * * This function is roughly equivalent to the sequence * utext_setNativeIndex(index); * utext_current32(); * (There is a subtle difference if the index is out of bounds by being less than zero - * utext_setNativeIndex(negative value) sets the index to zero, after which utext_current() * will return the char at zero. utext_char32At(negative index), on the other hand, will * return the U_SENTINEL value of -1.) * * @param ut the text to be accessed * @param nativeIndex the native index of the character to be accessed. If the index points * to other than the first unit of a multi-unit character, it will be adjusted * to the start of the character. * @return the code point at the specified index. * @stable ICU 3.4 */ U_STABLE UChar32 U_EXPORT2 utext_char32At(UText *ut, int64_t nativeIndex); /** * * Get the code point at the current iteration position, * or U_SENTINEL (-1) if the iteration has reached the end of * the input text. * * @param ut the text to be accessed. * @return the Unicode code point at the current iterator position. * @stable ICU 3.4 */ U_STABLE UChar32 U_EXPORT2 utext_current32(UText *ut); /** * Get the code point at the current iteration position of the UText, and * advance the position to the first index following the character. * * If the position is at the end of the text (the index following * the last character, which is also the length of the text), * return U_SENTINEL (-1) and do not advance the index. * * This is a post-increment operation. * * An inline macro version of this function, UTEXT_NEXT32(), * is available for performance critical use. * * @param ut the text to be accessed. * @return the Unicode code point at the iteration position. * @see UTEXT_NEXT32 * @stable ICU 3.4 */ U_STABLE UChar32 U_EXPORT2 utext_next32(UText *ut); /** * Move the iterator position to the character (code point) whose * index precedes the current position, and return that character. * This is a pre-decrement operation. * * If the initial position is at the start of the text (index of 0) * return U_SENTINEL (-1), and leave the position unchanged. * * An inline macro version of this function, UTEXT_PREVIOUS32(), * is available for performance critical use. * * @param ut the text to be accessed. * @return the previous UChar32 code point, or U_SENTINEL (-1) * if the iteration has reached the start of the text. * @see UTEXT_PREVIOUS32 * @stable ICU 3.4 */ U_STABLE UChar32 U_EXPORT2 utext_previous32(UText *ut); /** * Set the iteration index and return the code point at that index. * Leave the iteration index at the start of the following code point. * * This function is the most efficient and convenient way to * begin a forward iteration. The results are identical to the those * from the sequence * \code * utext_setIndex(); * utext_next32(); * \endcode * * @param ut the text to be accessed. * @param nativeIndex Iteration index, in the native units of the text provider. * @return Code point which starts at or before index, * or U_SENTINEL (-1) if it is out of bounds. * @stable ICU 3.4 */ U_STABLE UChar32 U_EXPORT2 utext_next32From(UText *ut, int64_t nativeIndex); /** * Set the iteration index, and return the code point preceding the * one specified by the initial index. Leave the iteration position * at the start of the returned code point. * * This function is the most efficient and convenient way to * begin a backwards iteration. * * @param ut the text to be accessed. * @param nativeIndex Iteration index in the native units of the text provider. * @return Code point preceding the one at the initial index, * or U_SENTINEL (-1) if it is out of bounds. * * @stable ICU 3.4 */ U_STABLE UChar32 U_EXPORT2 utext_previous32From(UText *ut, int64_t nativeIndex); /** * Get the current iterator position, which can range from 0 to * the length of the text. * The position is a native index into the input text, in whatever format it * may have (possibly UTF-8 for example), and may not always be the same as * the corresponding UChar (UTF-16) index. * The returned position will always be aligned to a code point boundary. * * @param ut the text to be accessed. * @return the current index position, in the native units of the text provider. * @stable ICU 3.4 */ U_STABLE int64_t U_EXPORT2 utext_getNativeIndex(const UText *ut); /** * Set the current iteration position to the nearest code point * boundary at or preceding the specified index. * The index is in the native units of the original input text. * If the index is out of range, it will be pinned to be within * the range of the input text. * <p> * It will usually be more efficient to begin an iteration * using the functions utext_next32From() or utext_previous32From() * rather than setIndex(). * <p> * Moving the index position to an adjacent character is best done * with utext_next32(), utext_previous32() or utext_moveIndex32(). * Attempting to do direct arithmetic on the index position is * complicated by the fact that the size (in native units) of a * character depends on the underlying representation of the character * (UTF-8, UTF-16, UTF-32, arbitrary codepage), and is not * easily knowable. * * @param ut the text to be accessed. * @param nativeIndex the native unit index of the new iteration position. * @stable ICU 3.4 */ U_STABLE void U_EXPORT2 utext_setNativeIndex(UText *ut, int64_t nativeIndex); /** * Move the iterator position by delta code points. The number of code points * is a signed number; a negative delta will move the iterator backwards, * towards the start of the text. * <p> * The index is moved by <code>delta</code> code points * forward or backward, but no further backward than to 0 and * no further forward than to utext_nativeLength(). * The resulting index value will be in between 0 and length, inclusive. * * @param ut the text to be accessed. * @param delta the signed number of code points to move the iteration position. * @return TRUE if the position could be moved the requested number of positions while * staying within the range [0 - text length]. * @stable ICU 3.4 */ U_STABLE UBool U_EXPORT2 utext_moveIndex32(UText *ut, int32_t delta); /** * Get the native index of the character preceding the current position. * If the iteration position is already at the start of the text, zero * is returned. * The value returned is the same as that obtained from the following sequence, * but without the side effect of changing the iteration position. * * \code * UText *ut = whatever; * ... * utext_previous(ut) * utext_getNativeIndex(ut); * \endcode * * This function is most useful during forwards iteration, where it will get the * native index of the character most recently returned from utext_next(). * * @param ut the text to be accessed * @return the native index of the character preceding the current index position, * or zero if the current position is at the start of the text. * @stable ICU 3.6 */ U_STABLE int64_t U_EXPORT2 utext_getPreviousNativeIndex(UText *ut); /** * * Extract text from a UText into a UChar buffer. The range of text to be extracted * is specified in the native indices of the UText provider. These may not necessarily * be UTF-16 indices. * <p> * The size (number of 16 bit UChars) of the data to be extracted is returned. The * full number of UChars is returned, even when the extracted text is truncated * because the specified buffer size is too small. * <p> * The extracted string will (if you are a user) / must (if you are a text provider) * be NUL-terminated if there is sufficient space in the destination buffer. This * terminating NUL is not included in the returned length. * <p> * The iteration index is left at the position following the last extracted character. * * @param ut the UText from which to extract data. * @param nativeStart the native index of the first character to extract.\ * If the specified index is out of range, * it will be pinned to be within 0 <= index <= textLength * @param nativeLimit the native string index of the position following the last * character to extract. If the specified index is out of range, * it will be pinned to be within 0 <= index <= textLength. * nativeLimit must be >= nativeStart. * @param dest the UChar (UTF-16) buffer into which the extracted text is placed * @param destCapacity The size, in UChars, of the destination buffer. May be zero * for precomputing the required size. * @param status receives any error status. * U_BUFFER_OVERFLOW_ERROR: the extracted text was truncated because the * buffer was too small. Returns number of UChars for preflighting. * @return Number of UChars in the data to be extracted. Does not include a trailing NUL. * * @stable ICU 3.4 */ U_STABLE int32_t U_EXPORT2 utext_extract(UText *ut, int64_t nativeStart, int64_t nativeLimit, UChar *dest, int32_t destCapacity, UErrorCode *status); /************************************************************************************ * * #define inline versions of selected performance-critical text access functions * Caution: do not use auto increment++ or decrement-- expressions * as parameters to these macros. * * For most use, where there is no extreme performance constraint, the * normal, non-inline functions are a better choice. The resulting code * will be smaller, and, if the need ever arises, easier to debug. * * These are implemented as #defines rather than real functions * because there is no fully portable way to do inline functions in plain C. * ************************************************************************************/ #ifndef U_HIDE_INTERNAL_API /** * inline version of utext_current32(), for performance-critical situations. * * Get the code point at the current iteration position of the UText. * Returns U_SENTINEL (-1) if the position is at the end of the * text. * * @internal ICU 4.4 technology preview */ #define UTEXT_CURRENT32(ut) \ ((ut)->chunkOffset < (ut)->chunkLength && ((ut)->chunkContents)[(ut)->chunkOffset]<0xd800 ? \ ((ut)->chunkContents)[((ut)->chunkOffset)] : utext_current32(ut)) #endif /* U_HIDE_INTERNAL_API */ /** * inline version of utext_next32(), for performance-critical situations. * * Get the code point at the current iteration position of the UText, and * advance the position to the first index following the character. * This is a post-increment operation. * Returns U_SENTINEL (-1) if the position is at the end of the * text. * * @stable ICU 3.4 */ #define UTEXT_NEXT32(ut) \ ((ut)->chunkOffset < (ut)->chunkLength && ((ut)->chunkContents)[(ut)->chunkOffset]<0xd800 ? \ ((ut)->chunkContents)[((ut)->chunkOffset)++] : utext_next32(ut)) /** * inline version of utext_previous32(), for performance-critical situations. * * Move the iterator position to the character (code point) whose * index precedes the current position, and return that character. * This is a pre-decrement operation. * Returns U_SENTINEL (-1) if the position is at the start of the text. * * @stable ICU 3.4 */ #define UTEXT_PREVIOUS32(ut) \ ((ut)->chunkOffset > 0 && \ (ut)->chunkContents[(ut)->chunkOffset-1] < 0xd800 ? \ (ut)->chunkContents[--((ut)->chunkOffset)] : utext_previous32(ut)) /** * inline version of utext_getNativeIndex(), for performance-critical situations. * * Get the current iterator position, which can range from 0 to * the length of the text. * The position is a native index into the input text, in whatever format it * may have (possibly UTF-8 for example), and may not always be the same as * the corresponding UChar (UTF-16) index. * The returned position will always be aligned to a code point boundary. * * @stable ICU 3.6 */ #define UTEXT_GETNATIVEINDEX(ut) \ ((ut)->chunkOffset <= (ut)->nativeIndexingLimit? \ (ut)->chunkNativeStart+(ut)->chunkOffset : \ (ut)->pFuncs->mapOffsetToNative(ut)) /** * inline version of utext_setNativeIndex(), for performance-critical situations. * * Set the current iteration position to the nearest code point * boundary at or preceding the specified index. * The index is in the native units of the original input text. * If the index is out of range, it will be pinned to be within * the range of the input text. * * @stable ICU 3.8 */ #define UTEXT_SETNATIVEINDEX(ut, ix) \ { int64_t __offset = (ix) - (ut)->chunkNativeStart; \ if (__offset>=0 && __offset<(int64_t)(ut)->nativeIndexingLimit && (ut)->chunkContents[__offset]<0xdc00) { \ (ut)->chunkOffset=(int32_t)__offset; \ } else { \ utext_setNativeIndex((ut), (ix)); } } /************************************************************************************ * * Functions related to writing or modifying the text. * These will work only with modifiable UTexts. Attempting to * modify a read-only UText will return an error status. * ************************************************************************************/ /** * Return TRUE if the text can be written (modified) with utext_replace() or * utext_copy(). For the text to be writable, the text provider must * be of a type that supports writing and the UText must not be frozen. * * Attempting to modify text when utext_isWriteable() is FALSE will fail - * the text will not be modified, and an error will be returned from the function * that attempted the modification. * * @param ut the UText to be tested. * @return TRUE if the text is modifiable. * * @see utext_freeze() * @see utext_replace() * @see utext_copy() * @stable ICU 3.4 * */ U_STABLE UBool U_EXPORT2 utext_isWritable(const UText *ut); /** * Test whether there is meta data associated with the text. * @see Replaceable::hasMetaData() * * @param ut The UText to be tested * @return TRUE if the underlying text includes meta data. * @stable ICU 3.4 */ U_STABLE UBool U_EXPORT2 utext_hasMetaData(const UText *ut); /** * Replace a range of the original text with a replacement text. * * Leaves the current iteration position at the position following the * newly inserted replacement text. * * This function is only available on UText types that support writing, * that is, ones where utext_isWritable() returns TRUE. * * When using this function, there should be only a single UText opened onto the * underlying native text string. Behavior after a replace operation * on a UText is undefined for any other additional UTexts that refer to the * modified string. * * @param ut the UText representing the text to be operated on. * @param nativeStart the native index of the start of the region to be replaced * @param nativeLimit the native index of the character following the region to be replaced. * @param replacementText pointer to the replacement text * @param replacementLength length of the replacement text, or -1 if the text is NUL terminated. * @param status receives any error status. Possible errors include * U_NO_WRITE_PERMISSION * * @return The signed number of (native) storage units by which * the length of the text expanded or contracted. * * @stable ICU 3.4 */ U_STABLE int32_t U_EXPORT2 utext_replace(UText *ut, int64_t nativeStart, int64_t nativeLimit, const UChar *replacementText, int32_t replacementLength, UErrorCode *status); /** * * Copy or move a substring from one position to another within the text, * while retaining any metadata associated with the text. * This function is used to duplicate or reorder substrings. * The destination index must not overlap the source range. * * The text to be copied or moved is inserted at destIndex; * it does not replace or overwrite any existing text. * * The iteration position is left following the newly inserted text * at the destination position. * * This function is only available on UText types that support writing, * that is, ones where utext_isWritable() returns TRUE. * * When using this function, there should be only a single UText opened onto the * underlying native text string. Behavior after a copy operation * on a UText is undefined in any other additional UTexts that refer to the * modified string. * * @param ut The UText representing the text to be operated on. * @param nativeStart The native index of the start of the region to be copied or moved * @param nativeLimit The native index of the character position following the region * to be copied. * @param destIndex The native destination index to which the source substring is * copied or moved. * @param move If TRUE, then the substring is moved, not copied/duplicated. * @param status receives any error status. Possible errors include U_NO_WRITE_PERMISSION * * @stable ICU 3.4 */ U_STABLE void U_EXPORT2 utext_copy(UText *ut, int64_t nativeStart, int64_t nativeLimit, int64_t destIndex, UBool move, UErrorCode *status); /** * <p> * Freeze a UText. This prevents any modification to the underlying text itself * by means of functions operating on this UText. * </p> * <p> * Once frozen, a UText can not be unfrozen. The intent is to ensure * that a the text underlying a frozen UText wrapper cannot be modified via that UText. * </p> * <p> * Caution: freezing a UText will disable changes made via the specific * frozen UText wrapper only; it will not have any effect on the ability to * directly modify the text by bypassing the UText. Any such backdoor modifications * are always an error while UText access is occurring because the underlying * text can get out of sync with UText's buffering. * </p> * * @param ut The UText to be frozen. * @see utext_isWritable() * @stable ICU 3.6 */ U_STABLE void U_EXPORT2 utext_freeze(UText *ut); /** * UText provider properties (bit field indexes). * * @see UText * @stable ICU 3.4 */ enum { /** * It is potentially time consuming for the provider to determine the length of the text. * @stable ICU 3.4 */ UTEXT_PROVIDER_LENGTH_IS_EXPENSIVE = 1, /** * Text chunks remain valid and usable until the text object is modified or * deleted, not just until the next time the access() function is called * (which is the default). * @stable ICU 3.4 */ UTEXT_PROVIDER_STABLE_CHUNKS = 2, /** * The provider supports modifying the text via the replace() and copy() * functions. * @see Replaceable * @stable ICU 3.4 */ UTEXT_PROVIDER_WRITABLE = 3, /** * There is meta data associated with the text. * @see Replaceable::hasMetaData() * @stable ICU 3.4 */ UTEXT_PROVIDER_HAS_META_DATA = 4, /** * Text provider owns the text storage. * Generally occurs as the result of a deep clone of the UText. * When closing the UText, the associated text must * also be closed/deleted/freed/ whatever is appropriate. * @stable ICU 3.6 */ UTEXT_PROVIDER_OWNS_TEXT = 5 }; /** * Function type declaration for UText.clone(). * * clone a UText. Much like opening a UText where the source text is itself * another UText. * * A deep clone will copy both the UText data structures and the underlying text. * The original and cloned UText will operate completely independently; modifications * made to the text in one will not effect the other. Text providers are not * required to support deep clones. The user of clone() must check the status return * and be prepared to handle failures. * * A shallow clone replicates only the UText data structures; it does not make * a copy of the underlying text. Shallow clones can be used as an efficient way to * have multiple iterators active in a single text string that is not being * modified. * * A shallow clone operation must not fail except for truly exceptional conditions such * as memory allocation failures. * * A UText and its clone may be safely concurrently accessed by separate threads. * This is true for both shallow and deep clones. * It is the responsibility of the Text Provider to ensure that this thread safety * constraint is met. * * @param dest A UText struct to be filled in with the result of the clone operation, * or NULL if the clone function should heap-allocate a new UText struct. * @param src The UText to be cloned. * @param deep TRUE to request a deep clone, FALSE for a shallow clone. * @param status Errors are returned here. For deep clones, U_UNSUPPORTED_ERROR * should be returned if the text provider is unable to clone the * original text. * @return The newly created clone, or NULL if the clone operation failed. * * @stable ICU 3.4 */ typedef UText * U_CALLCONV UTextClone(UText *dest, const UText *src, UBool deep, UErrorCode *status); /** * Function type declaration for UText.nativeLength(). * * @param ut the UText to get the length of. * @return the length, in the native units of the original text string. * @see UText * @stable ICU 3.4 */ typedef int64_t U_CALLCONV UTextNativeLength(UText *ut); /** * Function type declaration for UText.access(). Get the description of the text chunk * containing the text at a requested native index. The UText's iteration * position will be left at the requested index. If the index is out * of bounds, the iteration position will be left at the start or end * of the string, as appropriate. * * Chunks must begin and end on code point boundaries. A single code point * comprised of multiple storage units must never span a chunk boundary. * * * @param ut the UText being accessed. * @param nativeIndex Requested index of the text to be accessed. * @param forward If TRUE, then the returned chunk must contain text * starting from the index, so that start<=index<limit. * If FALSE, then the returned chunk must contain text * before the index, so that start<index<=limit. * @return True if the requested index could be accessed. The chunk * will contain the requested text. * False value if a chunk cannot be accessed * (the requested index is out of bounds). * * @see UText * @stable ICU 3.4 */ typedef UBool U_CALLCONV UTextAccess(UText *ut, int64_t nativeIndex, UBool forward); /** * Function type declaration for UText.extract(). * * Extract text from a UText into a UChar buffer. The range of text to be extracted * is specified in the native indices of the UText provider. These may not necessarily * be UTF-16 indices. * <p> * The size (number of 16 bit UChars) in the data to be extracted is returned. The * full amount is returned, even when the specified buffer size is smaller. * <p> * The extracted string will (if you are a user) / must (if you are a text provider) * be NUL-terminated if there is sufficient space in the destination buffer. * * @param ut the UText from which to extract data. * @param nativeStart the native index of the first character to extract. * @param nativeLimit the native string index of the position following the last * character to extract. * @param dest the UChar (UTF-16) buffer into which the extracted text is placed * @param destCapacity The size, in UChars, of the destination buffer. May be zero * for precomputing the required size. * @param status receives any error status. * If U_BUFFER_OVERFLOW_ERROR: Returns number of UChars for * preflighting. * @return Number of UChars in the data. Does not include a trailing NUL. * * @stable ICU 3.4 */ typedef int32_t U_CALLCONV UTextExtract(UText *ut, int64_t nativeStart, int64_t nativeLimit, UChar *dest, int32_t destCapacity, UErrorCode *status); /** * Function type declaration for UText.replace(). * * Replace a range of the original text with a replacement text. * * Leaves the current iteration position at the position following the * newly inserted replacement text. * * This function need only be implemented on UText types that support writing. * * When using this function, there should be only a single UText opened onto the * underlying native text string. The function is responsible for updating the * text chunk within the UText to reflect the updated iteration position, * taking into account any changes to the underlying string's structure caused * by the replace operation. * * @param ut the UText representing the text to be operated on. * @param nativeStart the index of the start of the region to be replaced * @param nativeLimit the index of the character following the region to be replaced. * @param replacementText pointer to the replacement text * @param replacmentLength length of the replacement text in UChars, or -1 if the text is NUL terminated. * @param status receives any error status. Possible errors include * U_NO_WRITE_PERMISSION * * @return The signed number of (native) storage units by which * the length of the text expanded or contracted. * * @stable ICU 3.4 */ typedef int32_t U_CALLCONV UTextReplace(UText *ut, int64_t nativeStart, int64_t nativeLimit, const UChar *replacementText, int32_t replacmentLength, UErrorCode *status); /** * Function type declaration for UText.copy(). * * Copy or move a substring from one position to another within the text, * while retaining any metadata associated with the text. * This function is used to duplicate or reorder substrings. * The destination index must not overlap the source range. * * The text to be copied or moved is inserted at destIndex; * it does not replace or overwrite any existing text. * * This function need only be implemented for UText types that support writing. * * When using this function, there should be only a single UText opened onto the * underlying native text string. The function is responsible for updating the * text chunk within the UText to reflect the updated iteration position, * taking into account any changes to the underlying string's structure caused * by the replace operation. * * @param ut The UText representing the text to be operated on. * @param nativeStart The index of the start of the region to be copied or moved * @param nativeLimit The index of the character following the region to be replaced. * @param nativeDest The destination index to which the source substring is copied or moved. * @param move If TRUE, then the substring is moved, not copied/duplicated. * @param status receives any error status. Possible errors include U_NO_WRITE_PERMISSION * * @stable ICU 3.4 */ typedef void U_CALLCONV UTextCopy(UText *ut, int64_t nativeStart, int64_t nativeLimit, int64_t nativeDest, UBool move, UErrorCode *status); /** * Function type declaration for UText.mapOffsetToNative(). * Map from the current UChar offset within the current text chunk to * the corresponding native index in the original source text. * * This is required only for text providers that do not use native UTF-16 indexes. * * @param ut the UText. * @return Absolute (native) index corresponding to chunkOffset in the current chunk. * The returned native index should always be to a code point boundary. * * @stable ICU 3.4 */ typedef int64_t U_CALLCONV UTextMapOffsetToNative(const UText *ut); /** * Function type declaration for UText.mapIndexToUTF16(). * Map from a native index to a UChar offset within a text chunk. * Behavior is undefined if the native index does not fall within the * current chunk. * * This function is required only for text providers that do not use native UTF-16 indexes. * * @param ut The UText containing the text chunk. * @param nativeIndex Absolute (native) text index, chunk->start<=index<=chunk->limit. * @return Chunk-relative UTF-16 offset corresponding to the specified native * index. * * @stable ICU 3.4 */ typedef int32_t U_CALLCONV UTextMapNativeIndexToUTF16(const UText *ut, int64_t nativeIndex); /** * Function type declaration for UText.utextClose(). * * A Text Provider close function is only required for provider types that make * allocations in their open function (or other functions) that must be * cleaned when the UText is closed. * * The allocation of the UText struct itself and any "extra" storage * associated with the UText is handled by the common UText implementation * and does not require provider specific cleanup in a close function. * * Most UText provider implementations do not need to implement this function. * * @param ut A UText object to be closed. * * @stable ICU 3.4 */ typedef void U_CALLCONV UTextClose(UText *ut); /** * (public) Function dispatch table for UText. * Conceptually very much like a C++ Virtual Function Table. * This struct defines the organization of the table. * Each text provider implementation must provide an * actual table that is initialized with the appropriate functions * for the type of text being handled. * @stable ICU 3.6 */ struct UTextFuncs { /** * (public) Function table size, sizeof(UTextFuncs) * Intended for use should the table grow to accommodate added * functions in the future, to allow tests for older format * function tables that do not contain the extensions. * * Fields are placed for optimal alignment on * 32/64/128-bit-pointer machines, by normally grouping together * 4 32-bit fields, * 4 pointers, * 2 64-bit fields * in sequence. * @stable ICU 3.6 */ int32_t tableSize; /** * (private) Alignment padding. * Do not use, reserved for use by the UText framework only. * @internal */ int32_t reserved1, /** @internal */ reserved2, /** @internal */ reserved3; /** * (public) Function pointer for UTextClone * * @see UTextClone * @stable ICU 3.6 */ UTextClone *clone; /** * (public) function pointer for UTextLength * May be expensive to compute! * * @see UTextLength * @stable ICU 3.6 */ UTextNativeLength *nativeLength; /** * (public) Function pointer for UTextAccess. * * @see UTextAccess * @stable ICU 3.6 */ UTextAccess *access; /** * (public) Function pointer for UTextExtract. * * @see UTextExtract * @stable ICU 3.6 */ UTextExtract *extract; /** * (public) Function pointer for UTextReplace. * * @see UTextReplace * @stable ICU 3.6 */ UTextReplace *replace; /** * (public) Function pointer for UTextCopy. * * @see UTextCopy * @stable ICU 3.6 */ UTextCopy *copy; /** * (public) Function pointer for UTextMapOffsetToNative. * * @see UTextMapOffsetToNative * @stable ICU 3.6 */ UTextMapOffsetToNative *mapOffsetToNative; /** * (public) Function pointer for UTextMapNativeIndexToUTF16. * * @see UTextMapNativeIndexToUTF16 * @stable ICU 3.6 */ UTextMapNativeIndexToUTF16 *mapNativeIndexToUTF16; /** * (public) Function pointer for UTextClose. * * @see UTextClose * @stable ICU 3.6 */ UTextClose *close; /** * (private) Spare function pointer * @internal */ UTextClose *spare1; /** * (private) Spare function pointer * @internal */ UTextClose *spare2; /** * (private) Spare function pointer * @internal */ UTextClose *spare3; }; /** * Function dispatch table for UText * @see UTextFuncs */ typedef struct UTextFuncs UTextFuncs; /** * UText struct. Provides the interface between the generic UText access code * and the UText provider code that works on specific kinds of * text (UTF-8, noncontiguous UTF-16, whatever.) * * Applications that are using predefined types of text providers * to pass text data to ICU services will have no need to view the * internals of the UText structs that they open. * * @stable ICU 3.6 */ struct UText { /** * (private) Magic. Used to help detect when UText functions are handed * invalid or uninitialized UText structs. * utext_openXYZ() functions take an initialized, * but not necessarily open, UText struct as an * optional fill-in parameter. This magic field * is used to check for that initialization. * Text provider close functions must NOT clear * the magic field because that would prevent * reuse of the UText struct. * @internal */ uint32_t magic; /** * (private) Flags for managing the allocation and freeing of * memory associated with this UText. * @internal */ int32_t flags; /** * Text provider properties. This set of flags is maintained by the * text provider implementation. * @stable ICU 3.4 */ int32_t providerProperties; /** * (public) sizeOfStruct=sizeof(UText) * Allows possible backward compatible extension. * * @stable ICU 3.4 */ int32_t sizeOfStruct; /* ------ 16 byte alignment boundary ----------- */ /** * (protected) Native index of the first character position following * the current chunk. * @stable ICU 3.6 */ int64_t chunkNativeLimit; /** * (protected) Size in bytes of the extra space (pExtra). * @stable ICU 3.4 */ int32_t extraSize; /** * (protected) The highest chunk offset where native indexing and * chunk (UTF-16) indexing correspond. For UTF-16 sources, value * will be equal to chunkLength. * * @stable ICU 3.6 */ int32_t nativeIndexingLimit; /* ---- 16 byte alignment boundary------ */ /** * (protected) Native index of the first character in the text chunk. * @stable ICU 3.6 */ int64_t chunkNativeStart; /** * (protected) Current iteration position within the text chunk (UTF-16 buffer). * This is the index to the character that will be returned by utext_next32(). * @stable ICU 3.6 */ int32_t chunkOffset; /** * (protected) Length the text chunk (UTF-16 buffer), in UChars. * @stable ICU 3.6 */ int32_t chunkLength; /* ---- 16 byte alignment boundary-- */ /** * (protected) pointer to a chunk of text in UTF-16 format. * May refer either to original storage of the source of the text, or * if conversion was required, to a buffer owned by the UText. * @stable ICU 3.6 */ const UChar *chunkContents; /** * (public) Pointer to Dispatch table for accessing functions for this UText. * @stable ICU 3.6 */ const UTextFuncs *pFuncs; /** * (protected) Pointer to additional space requested by the * text provider during the utext_open operation. * @stable ICU 3.4 */ void *pExtra; /** * (protected) Pointer to string or text-containing object or similar. * This is the source of the text that this UText is wrapping, in a format * that is known to the text provider functions. * @stable ICU 3.4 */ const void *context; /* --- 16 byte alignment boundary--- */ /** * (protected) Pointer fields available for use by the text provider. * Not used by UText common code. * @stable ICU 3.6 */ const void *p; /** * (protected) Pointer fields available for use by the text provider. * Not used by UText common code. * @stable ICU 3.6 */ const void *q; /** * (protected) Pointer fields available for use by the text provider. * Not used by UText common code. * @stable ICU 3.6 */ const void *r; /** * Private field reserved for future use by the UText framework * itself. This is not to be touched by the text providers. * @internal ICU 3.4 */ void *privP; /* --- 16 byte alignment boundary--- */ /** * (protected) Integer field reserved for use by the text provider. * Not used by the UText framework, or by the client (user) of the UText. * @stable ICU 3.4 */ int64_t a; /** * (protected) Integer field reserved for use by the text provider. * Not used by the UText framework, or by the client (user) of the UText. * @stable ICU 3.4 */ int32_t b; /** * (protected) Integer field reserved for use by the text provider. * Not used by the UText framework, or by the client (user) of the UText. * @stable ICU 3.4 */ int32_t c; /* ---- 16 byte alignment boundary---- */ /** * Private field reserved for future use by the UText framework * itself. This is not to be touched by the text providers. * @internal ICU 3.4 */ int64_t privA; /** * Private field reserved for future use by the UText framework * itself. This is not to be touched by the text providers. * @internal ICU 3.4 */ int32_t privB; /** * Private field reserved for future use by the UText framework * itself. This is not to be touched by the text providers. * @internal ICU 3.4 */ int32_t privC; }; /** * Common function for use by Text Provider implementations to allocate and/or initialize * a new UText struct. To be called in the implementation of utext_open() functions. * If the supplied UText parameter is null, a new UText struct will be allocated on the heap. * If the supplied UText is already open, the provider's close function will be called * so that the struct can be reused by the open that is in progress. * * @param ut pointer to a UText struct to be re-used, or null if a new UText * should be allocated. * @param extraSpace The amount of additional space to be allocated as part * of this UText, for use by types of providers that require * additional storage. * @param status Errors are returned here. * @return pointer to the UText, allocated if necessary, with extra space set up if requested. * @stable ICU 3.4 */ U_STABLE UText * U_EXPORT2 utext_setup(UText *ut, int32_t extraSpace, UErrorCode *status); // do not use #ifndef U_HIDE_INTERNAL_API around the following! /** * @internal * Value used to help identify correctly initialized UText structs. * Note: must be publicly visible so that UTEXT_INITIALIZER can access it. */ enum { UTEXT_MAGIC = 0x345ad82c }; /** * initializer to be used with local (stack) instances of a UText * struct. UText structs must be initialized before passing * them to one of the utext_open functions. * * @stable ICU 3.6 */ #define UTEXT_INITIALIZER { \ UTEXT_MAGIC, /* magic */ \ 0, /* flags */ \ 0, /* providerProps */ \ sizeof(UText), /* sizeOfStruct */ \ 0, /* chunkNativeLimit */ \ 0, /* extraSize */ \ 0, /* nativeIndexingLimit */ \ 0, /* chunkNativeStart */ \ 0, /* chunkOffset */ \ 0, /* chunkLength */ \ NULL, /* chunkContents */ \ NULL, /* pFuncs */ \ NULL, /* pExtra */ \ NULL, /* context */ \ NULL, NULL, NULL, /* p, q, r */ \ NULL, /* privP */ \ 0, 0, 0, /* a, b, c */ \ 0, 0, 0 /* privA,B,C, */ \ } U_CDECL_END #endif
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