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/*********************************************************
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* Copyright (C) 2008 VMware, Inc. All rights reserved.
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* This file is part of VMware View Open Client.
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*********************************************************/
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*******************************************************************************
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* Copyright (C) 2002-2006, International Business Machines
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* Corporation and others. All Rights Reserved.
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*******************************************************************************
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* tab size: 8 (not used)
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* created on: 2002jan18
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* created by: Markus W. Scherer
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* \brief C API: Unicode Character Iteration
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#include "unicode/utypes.h"
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class CharacterIterator;
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typedef struct UCharIterator UCharIterator; /**< C typedef for struct UCharIterator. @stable ICU 2.1 */
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* Origin constants for UCharIterator.getIndex() and UCharIterator.move().
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* @see UCharIteratorMove
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typedef enum UCharIteratorOrigin {
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UITER_START, UITER_CURRENT, UITER_LIMIT, UITER_ZERO, UITER_LENGTH
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} UCharIteratorOrigin;
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/** Constants for UCharIterator. @stable ICU 2.6 */
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* Constant value that may be returned by UCharIteratorMove
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* indicating that the final UTF-16 index is not known, but that the move succeeded.
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* This can occur when moving relative to limit or length, or
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* when moving relative to the current index after a setState()
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* when the current UTF-16 index is not known.
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* It would be very inefficient to have to count from the beginning of the text
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* just to get the current/limit/length index after moving relative to it.
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* The actual index can be determined with getIndex(UITER_CURRENT)
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* which will count the UChars if necessary.
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UITER_UNKNOWN_INDEX=-2
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* Constant for UCharIterator getState() indicating an error or
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* Returned by uiter_getState()/UCharIteratorGetState
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* when an error occurs.
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* Also, some UCharIterator implementations may not be able to return
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* a valid state for each position. This will be clearly documented
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* for each such iterator (none of the public ones here).
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#define UITER_NO_STATE ((uint32_t)0xffffffff)
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* Function type declaration for UCharIterator.getIndex().
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* Gets the current position, or the start or limit of the
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* This function may perform slowly for UITER_CURRENT after setState() was called,
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* or for UITER_LENGTH, because an iterator implementation may have to count
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* UChars if the underlying storage is not UTF-16.
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* @param iter the UCharIterator structure ("this pointer")
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* @param origin get the 0, start, limit, length, or current index
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* @return the requested index, or U_SENTINEL in an error condition
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* @see UCharIteratorOrigin
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typedef int32_t U_CALLCONV
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UCharIteratorGetIndex(UCharIterator *iter, UCharIteratorOrigin origin);
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* Function type declaration for UCharIterator.move().
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* Use iter->move(iter, index, UITER_ZERO) like CharacterIterator::setIndex(index).
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* Moves the current position relative to the start or limit of the
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* iteration range, or relative to the current position itself.
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* The movement is expressed in numbers of code units forward
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* or backward by specifying a positive or negative delta.
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* Out of bounds movement will be pinned to the start or limit.
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* This function may perform slowly for moving relative to UITER_LENGTH
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* because an iterator implementation may have to count the rest of the
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* UChars if the native storage is not UTF-16.
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* When moving relative to the limit or length, or
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* relative to the current position after setState() was called,
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* move() may return UITER_UNKNOWN_INDEX (-2) to avoid an inefficient
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* determination of the actual UTF-16 index.
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* The actual index can be determined with getIndex(UITER_CURRENT)
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* which will count the UChars if necessary.
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* See UITER_UNKNOWN_INDEX for details.
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* @param iter the UCharIterator structure ("this pointer")
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* @param delta can be positive, zero, or negative
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* @param origin move relative to the 0, start, limit, length, or current index
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* @return the new index, or U_SENTINEL on an error condition,
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* or UITER_UNKNOWN_INDEX when the index is not known.
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* @see UCharIteratorOrigin
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* @see UITER_UNKNOWN_INDEX
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typedef int32_t U_CALLCONV
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UCharIteratorMove(UCharIterator *iter, int32_t delta, UCharIteratorOrigin origin);
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* Function type declaration for UCharIterator.hasNext().
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* Check if current() and next() can still
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* return another code unit.
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* @param iter the UCharIterator structure ("this pointer")
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* @return boolean value for whether current() and next() can still return another code unit
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typedef UBool U_CALLCONV
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UCharIteratorHasNext(UCharIterator *iter);
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* Function type declaration for UCharIterator.hasPrevious().
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* Check if previous() can still return another code unit.
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* @param iter the UCharIterator structure ("this pointer")
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* @return boolean value for whether previous() can still return another code unit
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typedef UBool U_CALLCONV
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UCharIteratorHasPrevious(UCharIterator *iter);
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* Function type declaration for UCharIterator.current().
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* Return the code unit at the current position,
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* or U_SENTINEL if there is none (index is at the limit).
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* @param iter the UCharIterator structure ("this pointer")
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* @return the current code unit
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typedef UChar32 U_CALLCONV
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UCharIteratorCurrent(UCharIterator *iter);
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* Function type declaration for UCharIterator.next().
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* Return the code unit at the current index and increment
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* the index (post-increment, like s[i++]),
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* or return U_SENTINEL if there is none (index is at the limit).
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* @param iter the UCharIterator structure ("this pointer")
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* @return the current code unit (and post-increment the current index)
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typedef UChar32 U_CALLCONV
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UCharIteratorNext(UCharIterator *iter);
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* Function type declaration for UCharIterator.previous().
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* Decrement the index and return the code unit from there
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* (pre-decrement, like s[--i]),
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* or return U_SENTINEL if there is none (index is at the start).
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* @param iter the UCharIterator structure ("this pointer")
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* @return the previous code unit (after pre-decrementing the current index)
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typedef UChar32 U_CALLCONV
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UCharIteratorPrevious(UCharIterator *iter);
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* Function type declaration for UCharIterator.reservedFn().
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* Reserved for future use.
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* @param iter the UCharIterator structure ("this pointer")
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* @param something some integer argument
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* @return some integer
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typedef int32_t U_CALLCONV
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UCharIteratorReserved(UCharIterator *iter, int32_t something);
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* Function type declaration for UCharIterator.getState().
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* Get the "state" of the iterator in the form of a single 32-bit word.
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* It is recommended that the state value be calculated to be as small as
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* is feasible. For strings with limited lengths, fewer than 32 bits may
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* This is used together with setState()/UCharIteratorSetState
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* to save and restore the iterator position more efficiently than with
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* The iterator state is defined as a uint32_t value because it is designed
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* for use in ucol_nextSortKeyPart() which provides 32 bits to store the state
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* of the character iterator.
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* With some UCharIterator implementations (e.g., UTF-8),
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* getting and setting the UTF-16 index with existing functions
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* (getIndex(UITER_CURRENT) followed by move(pos, UITER_ZERO)) is possible but
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* relatively slow because the iterator has to "walk" from a known index
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* to the requested one.
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* This takes more time the farther it needs to go.
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* An opaque state value allows an iterator implementation to provide
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* an internal index (UTF-8: the source byte array index) for
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* fast, constant-time restoration.
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* After calling setState(), a getIndex(UITER_CURRENT) may be slow because
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* the UTF-16 index may not be restored as well, but the iterator can deliver
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* the correct text contents and move relative to the current position
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* without performance degradation.
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* Some UCharIterator implementations may not be able to return
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* a valid state for each position, in which case they return UITER_NO_STATE instead.
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* This will be clearly documented for each such iterator (none of the public ones here).
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* @param iter the UCharIterator structure ("this pointer")
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* @return the state word
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* @see UCharIteratorSetState
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* @see UITER_NO_STATE
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typedef uint32_t U_CALLCONV
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UCharIteratorGetState(const UCharIterator *iter);
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* Function type declaration for UCharIterator.setState().
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* Restore the "state" of the iterator using a state word from a getState() call.
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* The iterator object need not be the same one as for which getState() was called,
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* but it must be of the same type (set up using the same uiter_setXYZ function)
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* and it must iterate over the same string
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* (binary identical regardless of memory address).
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* For more about the state word see UCharIteratorGetState.
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* After calling setState(), a getIndex(UITER_CURRENT) may be slow because
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* the UTF-16 index may not be restored as well, but the iterator can deliver
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* the correct text contents and move relative to the current position
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* without performance degradation.
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* @param iter the UCharIterator structure ("this pointer")
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* @param state the state word from a getState() call
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* on a same-type, same-string iterator
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* @param pErrorCode Must be a valid pointer to an error code value,
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* which must not indicate a failure before the function call.
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* @see UCharIteratorGetState
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typedef void U_CALLCONV
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UCharIteratorSetState(UCharIterator *iter, uint32_t state, UErrorCode *pErrorCode);
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* C API for code unit iteration.
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* This can be used as a C wrapper around
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* CharacterIterator, Replaceable, or implemented using simple strings, etc.
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* There are two roles for using UCharIterator:
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* A "provider" sets the necessary function pointers and controls the "protected"
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* fields of the UCharIterator structure. A "provider" passes a UCharIterator
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* into C APIs that need a UCharIterator as an abstract, flexible string interface.
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* Implementations of such C APIs are "callers" of UCharIterator functions;
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* they only use the "public" function pointers and never access the "protected"
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* The current() and next() functions only check the current index against the
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* limit, and previous() only checks the current index against the start,
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* to see if the iterator already reached the end of the iteration range.
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* The assumption - in all iterators - is that the index is moved via the API,
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* which means it won't go out of bounds, or the index is modified by
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* user code that knows enough about the iterator implementation to set valid
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* UCharIterator functions return code unit values 0..0xffff,
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* or U_SENTINEL if the iteration bounds are reached.
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struct UCharIterator {
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* (protected) Pointer to string or wrapped object or similar.
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* Not used by caller.
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* (protected) Length of string or similar.
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* Not used by caller.
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* (protected) Start index or similar.
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* Not used by caller.
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* (protected) Current index or similar.
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* Not used by caller.
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* (protected) Limit index or similar.
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* Not used by caller.
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* (protected) Used by UTF-8 iterators and possibly others.
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int32_t reservedField;
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* (public) Returns the current position or the
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* start or limit index of the iteration range.
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* @see UCharIteratorGetIndex
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UCharIteratorGetIndex *getIndex;
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* (public) Moves the current position relative to the start or limit of the
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* iteration range, or relative to the current position itself.
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* The movement is expressed in numbers of code units forward
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* or backward by specifying a positive or negative delta.
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* @see UCharIteratorMove
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UCharIteratorMove *move;
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* (public) Check if current() and next() can still
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* return another code unit.
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* @see UCharIteratorHasNext
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UCharIteratorHasNext *hasNext;
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* (public) Check if previous() can still return another code unit.
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* @see UCharIteratorHasPrevious
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UCharIteratorHasPrevious *hasPrevious;
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* (public) Return the code unit at the current position,
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* or U_SENTINEL if there is none (index is at the limit).
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* @see UCharIteratorCurrent
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UCharIteratorCurrent *current;
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* (public) Return the code unit at the current index and increment
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* the index (post-increment, like s[i++]),
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* or return U_SENTINEL if there is none (index is at the limit).
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* @see UCharIteratorNext
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UCharIteratorNext *next;
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* (public) Decrement the index and return the code unit from there
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* (pre-decrement, like s[--i]),
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* or return U_SENTINEL if there is none (index is at the start).
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* @see UCharIteratorPrevious
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UCharIteratorPrevious *previous;
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* (public) Reserved for future use. Currently NULL.
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* @see UCharIteratorReserved
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UCharIteratorReserved *reservedFn;
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* (public) Return the state of the iterator, to be restored later with setState().
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* This function pointer is NULL if the iterator does not implement it.
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* @see UCharIteratorGet
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UCharIteratorGetState *getState;
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* (public) Restore the iterator state from the state word from a call
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* This function pointer is NULL if the iterator does not implement it.
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* @see UCharIteratorSet
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UCharIteratorSetState *setState;
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* Helper function for UCharIterator to get the code point
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* at the current index.
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* Return the code point that includes the code unit at the current position,
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* or U_SENTINEL if there is none (index is at the limit).
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* If the current code unit is a lead or trail surrogate,
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* then the following or preceding surrogate is used to form
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* the code point value.
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* @param iter the UCharIterator structure ("this pointer")
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* @return the current code point
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* @see UnicodeString::char32At()
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U_STABLE UChar32 U_EXPORT2
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uiter_current32(UCharIterator *iter);
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* Helper function for UCharIterator to get the next code point.
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* Return the code point at the current index and increment
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* the index (post-increment, like s[i++]),
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* or return U_SENTINEL if there is none (index is at the limit).
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* @param iter the UCharIterator structure ("this pointer")
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* @return the current code point (and post-increment the current index)
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U_STABLE UChar32 U_EXPORT2
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uiter_next32(UCharIterator *iter);
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* Helper function for UCharIterator to get the previous code point.
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* Decrement the index and return the code point from there
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* (pre-decrement, like s[--i]),
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* or return U_SENTINEL if there is none (index is at the start).
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* @param iter the UCharIterator structure ("this pointer")
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* @return the previous code point (after pre-decrementing the current index)
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U_STABLE UChar32 U_EXPORT2
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uiter_previous32(UCharIterator *iter);
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* Get the "state" of the iterator in the form of a single 32-bit word.
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* This is a convenience function that calls iter->getState(iter)
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* if iter->getState is not NULL;
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* if it is NULL or any other error occurs, then UITER_NO_STATE is returned.
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* Some UCharIterator implementations may not be able to return
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* a valid state for each position, in which case they return UITER_NO_STATE instead.
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* This will be clearly documented for each such iterator (none of the public ones here).
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* @param iter the UCharIterator structure ("this pointer")
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* @return the state word
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* @see UCharIteratorGetState
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* @see UITER_NO_STATE
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U_STABLE uint32_t U_EXPORT2
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uiter_getState(const UCharIterator *iter);
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* Restore the "state" of the iterator using a state word from a getState() call.
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* This is a convenience function that calls iter->setState(iter, state, pErrorCode)
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* if iter->setState is not NULL; if it is NULL, then U_UNSUPPORTED_ERROR is set.
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* @param iter the UCharIterator structure ("this pointer")
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* @param state the state word from a getState() call
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* on a same-type, same-string iterator
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* @param pErrorCode Must be a valid pointer to an error code value,
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* which must not indicate a failure before the function call.
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* @see UCharIteratorSetState
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U_STABLE void U_EXPORT2
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uiter_setState(UCharIterator *iter, uint32_t state, UErrorCode *pErrorCode);
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* Set up a UCharIterator to iterate over a string.
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* Sets the UCharIterator function pointers for iteration over the string s
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* with iteration boundaries start=index=0 and length=limit=string length.
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* The "provider" may set the start, index, and limit values at any time
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* within the range 0..length.
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* The length field will be ignored.
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* The string pointer s is set into UCharIterator.context without copying
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* or reallocating the string contents.
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* getState() simply returns the current index.
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* move() will always return the final index.
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* @param iter UCharIterator structure to be set for iteration
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* @param s String to iterate over
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* @param length Length of s, or -1 if NUL-terminated
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U_STABLE void U_EXPORT2
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uiter_setString(UCharIterator *iter, const UChar *s, int32_t length);
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* Set up a UCharIterator to iterate over a UTF-16BE string
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* (byte vector with a big-endian pair of bytes per UChar).
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* Everything works just like with a normal UChar iterator (uiter_setString),
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* except that UChars are assembled from byte pairs,
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* and that the length argument here indicates an even number of bytes.
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* getState() simply returns the current index.
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* move() will always return the final index.
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* @param iter UCharIterator structure to be set for iteration
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* @param s UTF-16BE string to iterate over
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* @param length Length of s as an even number of bytes, or -1 if NUL-terminated
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* (NUL means pair of 0 bytes at even index from s)
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* @see uiter_setString
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U_STABLE void U_EXPORT2
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uiter_setUTF16BE(UCharIterator *iter, const char *s, int32_t length);
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* Set up a UCharIterator to iterate over a UTF-8 string.
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* Sets the UCharIterator function pointers for iteration over the UTF-8 string s
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* with UTF-8 iteration boundaries 0 and length.
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* The implementation counts the UTF-16 index on the fly and
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* lazily evaluates the UTF-16 length of the text.
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* The start field is used as the UTF-8 offset, the limit field as the UTF-8 length.
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* When the reservedField is not 0, then it contains a supplementary code point
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* and the UTF-16 index is between the two corresponding surrogates.
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* At that point, the UTF-8 index is behind that code point.
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* The UTF-8 string pointer s is set into UCharIterator.context without copying
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* or reallocating the string contents.
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* getState() returns a state value consisting of
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* - the current UTF-8 source byte index (bits 31..1)
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* - a flag (bit 0) that indicates whether the UChar position is in the middle
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* of a surrogate pair
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* (from a 4-byte UTF-8 sequence for the corresponding supplementary code point)
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* getState() cannot also encode the UTF-16 index in the state value.
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* move(relative to limit or length), or
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* move(relative to current) after setState(), may return UITER_UNKNOWN_INDEX.
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* @param iter UCharIterator structure to be set for iteration
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* @param s UTF-8 string to iterate over
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* @param length Length of s in bytes, or -1 if NUL-terminated
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U_STABLE void U_EXPORT2
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uiter_setUTF8(UCharIterator *iter, const char *s, int32_t length);
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* Set up a UCharIterator to wrap around a C++ CharacterIterator.
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* Sets the UCharIterator function pointers for iteration using the
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* CharacterIterator charIter.
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* The CharacterIterator pointer charIter is set into UCharIterator.context
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* without copying or cloning the CharacterIterator object.
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* The other "protected" UCharIterator fields are set to 0 and will be ignored.
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* The iteration index and boundaries are controlled by the CharacterIterator.
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* getState() simply returns the current index.
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* move() will always return the final index.
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* @param iter UCharIterator structure to be set for iteration
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* @param charIter CharacterIterator to wrap
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U_STABLE void U_EXPORT2
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uiter_setCharacterIterator(UCharIterator *iter, U_NAMESPACE_QUALIFIER CharacterIterator *charIter);
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* Set up a UCharIterator to iterate over a C++ Replaceable.
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* Sets the UCharIterator function pointers for iteration over the
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* Replaceable rep with iteration boundaries start=index=0 and
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* length=limit=rep->length().
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* The "provider" may set the start, index, and limit values at any time
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* within the range 0..length=rep->length().
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* The length field will be ignored.
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* The Replaceable pointer rep is set into UCharIterator.context without copying
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* or cloning/reallocating the Replaceable object.
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* getState() simply returns the current index.
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* move() will always return the final index.
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* @param iter UCharIterator structure to be set for iteration
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* @param rep Replaceable to iterate over
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U_STABLE void U_EXPORT2
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uiter_setReplaceable(UCharIterator *iter, const U_NAMESPACE_QUALIFIER Replaceable *rep);
added
removed
lib/bora/unicode/unicode/uiter.h
