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authorAndreas Rottmann <a.rottmann@gmx.at>2009-09-14 12:32:44 +0200
committerAndreas Rottmann <a.rottmann@gmx.at>2009-09-14 12:32:44 +0200
commitfa095a4504cbe668e4244547e2c141597bea4ecf (patch)
tree06135820a286ffec47804e75fbf8a147e92acd2e /lib/unicase/context.h
Imported Upstream version 0.9.1upstream/0.9.1
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+/* Case-mapping contexts of UTF-8/UTF-16/UTF-32 substring.
+ Copyright (C) 2009 Free Software Foundation, Inc.
+ Written by Bruno Haible <bruno@clisp.org>, 2009.
+
+ This program is free software: you can redistribute it and/or modify it
+ under the terms of the GNU Lesser General Public License as published
+ by the Free Software Foundation; either version 3 of the License, or
+ (at your option) any later version.
+
+ This program is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ Lesser General Public License for more details.
+
+ You should have received a copy of the GNU Lesser General Public License
+ along with this program. If not, see <http://www.gnu.org/licenses/>. */
+
+
+/* The context of a prefix string combines the information of the "Before C"
+ conditions of the Unicode Standard,
+ <http://www.unicode.org/versions/Unicode5.0.0/ch03.pdf>, section 3.13,
+ table 3-14 "Context Specification for Casing".
+
+ casing_prefix_context_t contains the following fields:
+
+ // Helper for evaluating the FINAL_SIGMA condition:
+ // Last character that was not case-ignorable.
+ ucs4_t last_char_except_ignorable;
+
+ // Helper for evaluating the AFTER_SOFT_DOTTED and AFTER_I conditions:
+ // Last character that was of combining class 230 ("Above") or 0.
+ ucs4_t last_char_normal_or_above;
+
+ Three bits would be sufficient to carry the context information, but
+ that would require to invoke uc_is_cased and uc_is_property_soft_dotted
+ ahead of time, more often than actually needed. */
+
+
+/* The context of a suffix string combines the information of the "After C"
+ conditions of the Unicode Standard,
+ <http://www.unicode.org/versions/Unicode5.0.0/ch03.pdf>, section 3.13,
+ table 3-14 "Context Specification for Casing".
+
+ casing_suffix_context_t contains the following fields:
+
+ // For evaluating the FINAL_SIGMA condition:
+ // First character that was not case-ignorable.
+ ucs4_t first_char_except_ignorable;
+
+ // For evaluating the MORE_ABOVE condition:
+ // Bit 0 is set if the suffix contains a character of combining class
+ // 230 (Above) with no character of combining class 0 or 230 (Above)
+ // before it.
+ //
+ // For evaluating the BEFORE_DOT condition:
+ // Bit 1 is set if the suffix contains a COMBINING DOT ABOVE (U+0307)
+ // with no character of combining class 0 or 230 (Above) before it.
+ //
+ uint32_t bits;
+
+ Three bits would be sufficient to carry the context information, but
+ that would require to invoke uc_is_cased ahead of time, more often than
+ actually needed. */
+#define SCC_MORE_ABOVE_MASK 1
+#define SCC_BEFORE_DOT_MASK 2