ICU 51.2 51.2
C API for code unit iteration. More...
|const void *||context|
|(protected) Pointer to string or wrapped object or similar. |
|(protected) Length of string or similar. |
|(protected) Start index or similar. |
|(protected) Current index or similar. |
|(protected) Limit index or similar. |
|(protected) Used by UTF-8 iterators and possibly others. |
|(public) Returns the current position or the start or limit index of the iteration range. |
|(public) Moves the current position relative to the start or limit of the iteration range, or relative to the current position itself. |
|(public) Check if current() and next() can still return another code unit. |
|(public) Check if previous() can still return another code unit. |
|(public) Return the code unit at the current position, or U_SENTINEL if there is none (index is at the limit). |
|(public) Return the code unit at the current index and increment the index (post-increment, like s[i++]), or return U_SENTINEL if there is none (index is at the limit). |
|(public) Decrement the index and return the code unit from there (pre-decrement, like s[--i]), or return U_SENTINEL if there is none (index is at the start). |
|(public) Reserved for future use. |
|(public) Return the state of the iterator, to be restored later with setState(). |
|(public) Restore the iterator state from the state word from a call to getState(). |
C API for code unit iteration.
This can be used as a C wrapper around CharacterIterator, Replaceable, or implemented using simple strings, etc.
There are two roles for using UCharIterator:
A "provider" sets the necessary function pointers and controls the "protected" fields of the UCharIterator structure. A "provider" passes a UCharIterator into C APIs that need a UCharIterator as an abstract, flexible string interface.
Implementations of such C APIs are "callers" of UCharIterator functions; they only use the "public" function pointers and never access the "protected" fields directly.
The current() and next() functions only check the current index against the limit, and previous() only checks the current index against the start, to see if the iterator already reached the end of the iteration range.
The assumption - in all iterators - is that the index is moved via the API, which means it won't go out of bounds, or the index is modified by user code that knows enough about the iterator implementation to set valid index values.
UCharIterator functions return code unit values 0..0xffff, or U_SENTINEL if the iteration bounds are reached.
|const void* UCharIterator::context|
(public) Moves the current position relative to the start or limit of the iteration range, or relative to the current position itself.
The movement is expressed in numbers of code units forward or backward by specifying a positive or negative delta.