FreeBSD Manual Pages
UNICODE_LINE_BREAK(3) Courier Unicode Library UNICODE_LINE_BREAK(3) NAME unicode_line_break, unicode_lb_init, unicode_lb_set_opts, unicode_lb_next, unicode_lb_next_cnt, unicode_lb_end, unicode_lbc_init, uni- code_lbc_set_opts, unicode_lbc_next, unicode_lbc_next_cnt, unicode_lbc_end - calculate mandatory or allowed line breaks SYNOPSIS #include <courier-unicode.h> unicode_lb_info_t unicode_lb_init(int (*cb_func)(int, void *), void *cb_arg); void unicode_lb_set_opts(unicode_lb_info_t lb, int opts); int unicode_lb_next(unicode_lb_info_t lb, char32_t c); int unicode_lb_next_cnt(unicode_lb_info_t lb, const char32_t *cptr, size_t cnt); int unicode_lb_end(unicode_lb_info_t lb); unicode_lbc_info_t unicode_lbc_init(int (*cb_func)(int, char32_t, void *), void *cb_arg); void unicode_lbc_set_opts(unicode_lbc_info_t lb, int opts); int unicode_lbc_next(unicode_lb_info_t lb, char32_t c); int unicode_lbc_next_cnt(unicode_lb_info_t lb, const char32_t *cptr, size_t cnt); int unicode_lbc_end(unicode_lb_info_t lb); DESCRIPTION These functions implement the unicode line breaking algorithm. Invoke uni- code_lb_init() to initialize the line breaking algorithm. The first parame- ter is a callback function. The second parameter is an opaque pointer. The callback function gets invoked with two parameters. The first parameter is one of three values: UNICODE_LB_MANDATORY, UNICODE_LB_NONE, or UNI- CODE_LB_ALLOWED, as described below. The second parameter is the opaque pointer that was passed to unicode_lb_init(); the opaque pointer is not subject to any further interpretation by these functions. unicode_lb_init() returns an opaque handle. Repeated invocations of uni- code_lb_next(), passing the handle and one unicode character at a time, de- fines a sequence of unicode characters over which the line breaking algo- rithm calculation takes place. unicode_lb_next_cnt() is a shortcut for in- voking unicode_lb_next() repeatedly over an array cptr containing cnt uni- code characters. unicode_lb_end() denotes the end of the unicode character sequence. After the call to unicode_lb_end() the line breaking unicode_lb_info_t handle is no longer valid. Between the call to unicode_lb_init() and unicode_lb_end(), the callback function gets invoked exactly once for each unicode character given to uni- code_lb_next() or unicode_lb_next_cnt(). Usually each call to uni- code_lb_next() results in the callback function getting invoked immedi- ately, but it does not have to be. It's possible that a call to uni- code_lb_next() returns without invoking the callback function, and some subsequent call to unicode_lb_next() (or unicode_lb_end()) invokes the callback function more than once, to catch up. The contract is that before unicode_lb_end() returns, the callback function gets invoked the exact num- ber of times as the number of characters in the unicode sequence defined by the intervening calls to unicode_lb_next() and unicode_lb_next_cnt(), un- less an error occurs. Each call to the callback function reports the calculated line breaking status of the corresponding character in the unicode character sequence: UNICODE_LB_MANDATORY A line break is MANDATORY before the corresponding character. UNICODE_LB_NONE A line break is PROHIBITED before the corresponding character. UNICODE_LB_ALLOWED A line break is OPTIONAL before the corresponding character. The callback function should return 0. A non-zero value indicates to the line breaking algorithm that an error has occurred. unicode_lb_next() and unicode_lb_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_lb_next() and unicode_lb_next_cnt() immediately returning the same value. unicode_lb_end() must be invoked to destroy the line breaking handle even if unicode_lb_next() and unicode_lb_next_cnt() returned an error indica- tion. It's also possible that, under normal circumstances, unicode_lb_end() invokes the callback function one or more times. The return value from uni- code_lb_end() has the same meaning as from unicode_lb_next() and uni- code_lb_next_cnt(); however in all cases after unicode_lb_end() returns the line breaking handle is no longer valid. Alternative callback function unicode_lbc_init(), unicode_lbc_next(), unicode_lbc_next_cnt(), uni- code_lbc_end() are alternative functions that implement the same algorithm. The only difference is that the callback function receives an extra parame- ter, the unicode character value to which the line breaking status applies to, passed through from the input unicode character sequence. Options unicode_lb_set_opts() and unicode_lbc_set_opts() enable non-default options for the line breaking algorithm. These functions must be called immediately after unicode_lb_init() or unicode_lbc_init(), and before any other func- tion. opts is a bitmask that can contain the following values: UNICODE_LB_OPT_PRBREAK Enables a modified LB24 rule. This prevents plus signs, as in "C++" from breaking. This flag adds the following rules to the LB24 rule: PR x PR AL x PR ID x PR UNICODE_LB_OPT_SYBREAK Tailored breaking rules for the "/" character. This prevents breaking after the "/" character (think URLs); including an exception to the "x SY" rule in LB13. This flag adds the following rules to the LB24 rule: SY x EX SY x AL SY x ID SP / SY, which takes precedence over "x SY". UNICODE_LB_OPT_DASHWJ This flag reclassifies U+2013 and U+2014 as class WJ, prohibiting breaks before and after the m-dash and the n-dash unicode characters. SEE ALSO courier-unicode(7), unicode::linebreak(3), TR-14[1] AUTHOR Sam Varshavchik Author NOTES 1. TR-14 https://www.unicode.org/reports/tr14/tr14-55.html Courier Unicode Library 04/12/2026 UNICODE_LINE_BREAK(3)
NAME | SYNOPSIS | DESCRIPTION | SEE ALSO | AUTHOR | NOTES
Want to link to this manual page? Use this URL:
<https://man.freebsd.org/cgi/man.cgi?query=unicode_lb_set_opts&sektion=3&manpath=FreeBSD+Ports+15.1.quarterly>