ICU-924 add "Remove" transliterator

X-SVN-Rev: 4440

icu4c/source/i18n/Makefile.in

@@ -70,7 +70,7 @@ ucol.o ucol_bld.o ucol_elm.o ucol_cnt.o ucol_tok.o ucol_wgt.o ucoleitr.o \
 udat.o umsg.o \
 unifltlg.o unirange.o uniset.o unitohex.o unum.o \
 dbbi.o dbbi_tbl.o rbbi.o rbbi_tbl.o brkdict.o nultrans.o jamohang.o hangjamo.o \
- utrans.o
+remtrans.o utrans.o
 
 STATIC_OBJECTS = $(OBJECTS:.o=.$(STATIC_O))
 

icu4c/source/i18n/i18n.dsp

@@ -466,6 +466,10 @@ SOURCE=.\rbt_set.cpp
 # End Source File
 # Begin Source File
 
+SOURCE=.\remtrans.cpp
+# End Source File
+# Begin Source File
+
 SOURCE=.\simpletz.cpp
 
 !IF  "$(CFG)" == "i18n - Win32 Release"
@@ -1413,6 +1417,10 @@ SOURCE=.\rbt_set.h
 # End Source File
 # Begin Source File
 
+SOURCE=.\unicode\remtrans.h
+# End Source File
+# Begin Source File
+
 SOURCE=.\unicode\simpletz.h
 
 !IF  "$(CFG)" == "i18n - Win32 Release"

icu4c/source/i18n/remtrans.cpp

@@ -0,0 +1,54 @@
+/*
+**********************************************************************
+*   Copyright (c) 2001, International Business Machines
+*   Corporation and others.  All Rights Reserved.
+**********************************************************************
+*   Date        Name        Description
+*   04/02/2001  aliu        Creation.
+**********************************************************************
+*/
+#include "unicode/remtrans.h"
+
+const UnicodeString RemoveTransliterator::ID = UnicodeString("Remove", "");
+
+Transliterator* RemoveTransliterator::clone(void) const {
+    return new RemoveTransliterator();
+}
+
+void RemoveTransliterator::handleTransliterate(Replaceable& text, UTransPosition& offsets,
+                                               UBool /*isIncremental*/) const {
+    // Find runs of unfiltered characters and replace them with the
+    // empty string.  This loop has been optimized to what is probably
+    // an unnecessary degree.
+    UnicodeString empty;
+    int32_t start = offsets.start;
+    for (;;) {
+        // Find first unfiltered character, if any
+        while (start < offsets.limit &&
+               filteredCharAt(text, start) == 0xFFFE) {
+            ++start;
+        }
+        if (start >= offsets.limit) {
+            break;
+        }
+
+        // assert(start < offsets.limit &&
+        //        filteredCharAt(text, start) != 0xFFFE);
+
+        // Find last unfiltered character
+        int32_t limit = start+1; // sic: +1
+        while (limit < offsets.limit &&
+               filteredCharAt(text, limit) != 0xFFFE) {
+            ++limit;
+        }
+
+        // assert(start < limit);
+
+        // Remove characters
+        text.handleReplaceBetween(start, limit, empty);
+        limit -= start; // limit <= deleted length
+        offsets.contextLimit -= limit;
+        offsets.limit -= limit;
+    }
+    offsets.start = start;
+}

icu4c/source/i18n/unicode/remtrans.h

@@ -0,0 +1,54 @@
+/*
+**********************************************************************
+*   Copyright (c) 2001, International Business Machines
+*   Corporation and others.  All Rights Reserved.
+**********************************************************************
+*   Date        Name        Description
+*   04/02/2001  aliu        Creation.
+**********************************************************************
+*/
+#ifndef REMTRANS_H
+#define REMTRANS_H
+
+#include "unicode/translit.h"
+
+/**
+ * A transliterator that removes text.
+ * @author Alan Liu
+ */
+class U_I18N_API RemoveTransliterator : public Transliterator {
+
+public:
+
+    /**
+     * ID for this transliterator.
+     */
+    static const UnicodeString ID; // public for Transliterator
+
+    /**
+     * Constructs a transliterator.
+     */
+    RemoveTransliterator();
+
+    /**
+     * Destructor.
+     */
+    virtual ~RemoveTransliterator();
+
+    /**
+     * Transliterator API.
+     */
+    Transliterator* clone(void) const;
+
+    /**
+     * Implements {@link Transliterator#handleTransliterate}.
+     */
+    virtual void handleTransliterate(Replaceable& text, UTransPosition& offset,
+                                     UBool isIncremental) const;
+};
+
+inline RemoveTransliterator::RemoveTransliterator() : Transliterator(ID, 0) {}
+
+inline RemoveTransliterator::~RemoveTransliterator() {}
+
+#endif