Check in the pristine copy of ICU 4.6...

icu46/source/common/unifilt.cpp

+/*
+**********************************************************************
+* Copyright (c) 2001-2004, International Business Machines
+* Corporation and others.  All Rights Reserved.
+**********************************************************************
+*   Date        Name        Description
+*   07/18/01    aliu        Creation.
+**********************************************************************
+*/
+
+#include "unicode/unifilt.h"
+#include "unicode/rep.h"
+
+U_NAMESPACE_BEGIN
+UOBJECT_DEFINE_ABSTRACT_RTTI_IMPLEMENTATION(UnicodeFilter)
+
+
+/* Define this here due to the lack of another file.
+   It can't be defined in the header */
+UnicodeMatcher::~UnicodeMatcher() {}
+
+UnicodeFilter::~UnicodeFilter() {}
+
+/**
+ * UnicodeFunctor API.  Cast 'this' to a UnicodeMatcher* pointer
+ * and return the pointer.
+ */
+UnicodeMatcher* UnicodeFilter::toMatcher() const {
+    return (UnicodeMatcher*) this;
+}
+
+void UnicodeFilter::setData(const TransliterationRuleData*) {}
+
+/**
+ * Default implementation of UnicodeMatcher::matches() for Unicode
+ * filters.  Matches a single code point at offset (either one or
+ * two 16-bit code units).
+ */
+UMatchDegree UnicodeFilter::matches(const Replaceable& text,
+                                    int32_t& offset,
+                                    int32_t limit,
+                                    UBool incremental) {
+    UChar32 c;
+    if (offset < limit &&
+        contains(c = text.char32At(offset))) {
+        offset += UTF_CHAR_LENGTH(c);
+        return U_MATCH;
+    }
+    if (offset > limit &&
+        contains(c = text.char32At(offset))) {
+        // Backup offset by 1, unless the preceding character is a
+        // surrogate pair -- then backup by 2 (keep offset pointing at
+        // the lead surrogate).
+        --offset;
+        if (offset >= 0) {
+            offset -= UTF_CHAR_LENGTH(text.char32At(offset)) - 1;
+        }
+        return U_MATCH;
+    }
+    if (incremental && offset == limit) {
+        return U_PARTIAL_MATCH;
+    }
+    return U_MISMATCH;
+}
+
+U_NAMESPACE_END
+
+//eof