NAME

       unicode_wb_init, unicode_wb_next, unicode_wb_next_cnt, unicode_wb_end, unicode_wbscan_init,
       unicode_wbscan_next, unicode_wbscan_end - calculate word breaks

SYNOPSIS

       #include <courier-unicode.h>

       unicode_wb_info_t unicode_wb_init(int (*cb_func)(int, void *), void *cb_arg);

       int unicode_wb_next(unicode_wb_info_t wb, char32_t c);

       int unicode_wb_next_cnt(unicode_wb_info_t wb, const char32_t *cptr, size_t cnt);

       int unicode_wb_end(unicode_wb_info_t wb);

       unicode_wbscan_info_t unicode_wbscan_init(void);

       int unicode_wbscan_next(unicode_wbscan_info_t wbs, char32_t c);

       size_t unicode_wbscan_end(unicode_wbscan_info_t wbs);

DESCRIPTION

       These functions implement the unicode word breaking algorithm. Invoke unicode_wb_init() to initialize the
       word breaking algorithm. The first parameter is a callback function. The second parameter is an opaque
       pointer. The callback function gets invoked with two parameters. The second parameter is the opaque
       pointer that was given to unicode_wb_init(); and the opaque pointer is not subject to any further
       interpretation by these functions.

       unicode_wb_init() returns an opaque handle. Repeated invocations of unicode_wb_next(), passing the
       handle, and one unicode character defines a sequence of unicode characters over which the word breaking
       algorithm calculation takes place.  unicode_wb_next_cnt() is a shortcut for invoking unicode_wb_next()
       repeatedly over an array cptr containing cnt unicode characters.

       unicode_wb_end() denotes the end of the unicode character sequence. After the call to unicode_wb_end()
       the word breaking unicode_wb_info_t handle is no longer valid.

       Between the call to unicode_wb_init() and unicode_wb_end(), the callback function gets invoked exactly
       once for each unicode character given to unicode_wb_next() or unicode_wb_next_cnt(). Usually each call to
       unicode_wb_next() results in the callback function getting invoked immediately, but it does not have to
       be. It's possible that a call to unicode_wb_next() returns without invoking the callback function, and
       some subsequent call to unicode_wb_next() (or unicode_wb_end()) invokes the callback function more than
       once, to catch things up. The contract is that before unicode_wb_end() returns, the callback function
       gets invoked the exact number of times as the number of characters in the unicode sequence defined by the
       intervening calls to unicode_wb_next() and unicode_wb_next_cnt(), unless an error occurs.

       Each call to the callback function reports the calculated wordbreaking status of the corresponding
       character in the unicode character sequence. If the parameter to the callback function is non zero, a
       word break is permitted before the corresponding character. A zero value indicates that a word break is
       prohibited before the corresponding character.

       The callback function should return 0. A non-zero value indicates to the word breaking algorithm that an
       error has occurred.  unicode_wb_next() and unicode_wb_next_cnt() return zero either if they never invoked
       the callback function, or if each call to the callback function returned zero. A non zero return from the
       callback function results in unicode_wb_next() and unicode_wb_next_cnt() immediately returning the same
       value.

       unicode_wb_end() must be invoked to destroy the word breaking handle even if unicode_wb_next() and
       unicode_wb_next_cnt() returned an error indication. It's also possible that, under normal circumstances,
       unicode_wb_end() invokes the callback function one or more times. The return value from unicode_wb_end()
       has the same meaning as from unicode_wb_next() and unicode_wb_next_cnt(); however in all cases after
       unicode_wb_end() returns the line breaking handle is no longer valid.

   Word scan
       unicode_wbscan_init(), unicode_wbscan_next() and unicode_wbscan_end scan for the next word boundary in a
       unicode character sequence.  unicode_wbscan_init() obtains a handle, then unicode_wbscan_next() gets
       repeatedly invoked to define the unicode character sequence.  unicode_wbscan_end() deallocates the handle
       and returns the number of leading characters in the unicode character sequence up to the first word
       break.

       A non-0 return value from unicode_wbscan_next() indicates that the word boundary is already known, and
       any further calls to unicode_wbscan_next() will be ignored.  unicode_wbscan_end() must still be called,
       to obtain the unicode character count.

SEE ALSO

       TR-29[1], courier-unicode(7), unicode::wordbreak(3), unicode_convert_tocase(3), unicode_line_break(3),
       unicode_grapheme_break(3).

AUTHOR

       Sam Varshavchik
           Author

NOTES

        1. TR-29
           http://www.unicode.org/reports/tr29/tr29-27.html

Courier Unicode Library                            11/25/2020                              UNICODE_WORD_BREAK(3)