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author | Manuel A. Fernandez Montecelo <manuel.montezelo@gmail.com> | 2016-05-27 14:28:30 +0100 |
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committer | Manuel A. Fernandez Montecelo <manuel.montezelo@gmail.com> | 2016-05-27 14:28:30 +0100 |
commit | a9a31b1de5776a3b08a82101a4fa711294f0dd1d (patch) | |
tree | 159134a624e51509f40ed8823249f09a70d1dda3 /doc/unigbrk.texi | |
parent | 5f2b09982312c98863eb9a8dfe2c608b81f58259 (diff) |
Imported Upstream version 0.9.6+really0.9.3upstream/0.9.6+really0.9.3
Diffstat (limited to 'doc/unigbrk.texi')
-rw-r--r-- | doc/unigbrk.texi | 126 |
1 files changed, 0 insertions, 126 deletions
diff --git a/doc/unigbrk.texi b/doc/unigbrk.texi deleted file mode 100644 index 196bd9fd..00000000 --- a/doc/unigbrk.texi +++ /dev/null @@ -1,126 +0,0 @@ -@node unigbrk.h -@chapter Grapheme cluster breaks in strings @code{<unigbrk.h>} - -@cindex grapheme cluster breaks -@cindex grapheme cluster boundaries -@cindex breaks, grapheme cluster -@cindex boundaries, between grapheme clusters -This include file declares functions for determining where in a string -``grapheme clusters'' start and end. A ``grapheme cluster'' is an -approximation to a user-perceived character, which sometimes -corresponds to multiple Unicode characters. Editing operations such as -mouse selection, cursor movement, and backspacing often operate on -grapheme clusters as units, not on individual characters. - -Some grapheme clusters are built from a base character and a combining -character. The letter @samp{@'e}, -for example, is most commonly represented in Unicode as a single -character U+00E8 @sc{LATIN SMALL LETTER E WITH ACUTE}. It is, -however, equally valid to use the pair of characters U+0065 @sc{LATIN -SMALL LETTER E} followed by U+0301 @sc{COMBINING ACUTE ACCENT}. Since -the user would perceive this pair of characters as a single character, -they would be grouped into a single grapheme cluster. - -But there are also grapheme clusters that consist of several base characters. -For example, a Devanagari letter and a Devanagari vowel sign that follows it -may form a grapheme cluster. Similarly, some pairs of Thai characters and -Hangul syllables (formed by two or three Hangul characters) are grapheme -clusters. - -@menu -* Grapheme cluster breaks in a string:: -* Grapheme cluster break property:: -@end menu - -@node Grapheme cluster breaks in a string -@section Grapheme cluster breaks in a string - -The following functions find a single boundary between grapheme -clusters in a string. - -@deftypefun void u8_grapheme_next (const uint8_t *@var{s}, const uint8_t *@var{end}) -@deftypefunx void u16_grapheme_next (const uint16_t *@var{s}, const uint16_t *@var{end}) -@deftypefunx void u32_grapheme_next (const uint32_t *@var{s}, const uint32_t *@var{end}) -Returns the start of the next grapheme cluster following @var{s}, -or @var{end} if no grapheme cluster break is encountered before it. -Returns NULL if and only if @code{@var{s} == @var{end}}. -@end deftypefun - -@deftypefun void u8_grapheme_prev (const uint8_t *@var{s}, const uint8_t *@var{start}) -@deftypefunx void u16_grapheme_prev (const uint16_t *@var{s}, const uint16_t *@var{start}) -@deftypefunx void u32_grapheme_prev (const uint32_t *@var{s}, const uint32_t *@var{start}) -Returns the start of the grapheme cluster preceding @var{s}, or -@var{start} if no grapheme cluster break is encountered before it. -Returns NULL if and only if @code{@var{s} == @var{start}}. -@end deftypefun - -The following functions determine all of the grapheme cluster -boundaries in a string. - -@deftypefun void u8_grapheme_breaks (const uint8_t *@var{s}, size_t @var{n}, char *@var{p}) -@deftypefunx void u16_grapheme_breaks (const uint16_t *@var{s}, size_t @var{n}, char *@var{p}) -@deftypefunx void u32_grapheme_breaks (const uint32_t *@var{s}, size_t @var{n}, char *@var{p}) -@deftypefunx void ulc_grapheme_breaks (const char *@var{s}, size_t @var{n}, char *@var{p}) -Determines the grapheme cluster break points in @var{s}, an array of -@var{n} units, and stores the result at @code{@var{p}[0..@var{n}-1]}. -@table @asis -@item @code{@var{p}[i] = 1} -means that there is a grapheme cluster boundary between -@code{@var{s}[i-1]} and @code{@var{s}[i]}. -@item @code{@var{p}[i] = 0} -means that @code{@var{s}[i-1]} and @code{@var{s}[i]} are part of the -same grapheme cluster. -@end table -@code{@var{p}[0]} is always set to 1, because there is always a -grapheme cluster break at start of text. -@end deftypefun - -@node Grapheme cluster break property -@section Grapheme cluster break property - -This is a more low-level API. The grapheme cluster break property is a -property defined in Unicode Standard Annex #29, section ``Grapheme Cluster -Boundaries'', see -@url{http://www.unicode.org/reports/tr29/#Grapheme_Cluster_Boundaries}.@texnl{} -It is used for determining the grapheme cluster breaks in a string. - -The following are the possible values of the grapheme cluster break -property. More values may be added in the future. - -@deftypevr Constant int GBP_OTHER -@deftypevrx Constant int GBP_CR -@deftypevrx Constant int GBP_LF -@deftypevrx Constant int GBP_CONTROL -@deftypevrx Constant int GBP_EXTEND -@deftypevrx Constant int GBP_PREPEND -@deftypevrx Constant int GBP_SPACINGMARK -@deftypevrx Constant int GBP_L -@deftypevrx Constant int GBP_V -@deftypevrx Constant int GBP_T -@deftypevrx Constant int GBP_LV -@deftypevrx Constant int GBP_LVT -@end deftypevr - -The following function looks up the grapheme cluster break property of a -character. - -@deftypefun int uc_graphemeclusterbreak_property (ucs4_t @var{uc}) -Returns the Grapheme_Cluster_Break property of a Unicode character. -@end deftypefun - -The following function determines whether there is a grapheme cluster -break between two Unicode characters. It is the primitive upon which -the higher-level functions in the previous section are directly based. - -@deftypefun bool uc_is_grapheme_break (ucs4_t @var{a}, ucs4_t @var{b}) -Returns true if there is an grapheme cluster boundary between Unicode -characters @var{a} and @var{b}. - -There is always a grapheme cluster break at the start or end of text. -You can specify zero for @var{a} or @var{b} to indicate start of text or end -of text, respectively. - -This implements the extended (not legacy) grapheme cluster rules -described in the Unicode standard, because the standard says that they -are preferred. -@end deftypefun |