--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/fontservices/textshaperplugin/IcuSource/layout/IndicLayoutEngine.h	Tue Feb 02 02:02:46 2010 +0200
@@ -0,0 +1,162 @@
+
+/*
+ *
+ * (C) Copyright IBM Corp. 1998-2005 - All Rights Reserved
+ *
+ */
+
+#ifndef __INDICLAYOUTENGINE_H
+#define __INDICLAYOUTENGINE_H
+
+#include "LETypes.h"
+#include "LEFontInstance.h"
+#include "LEGlyphFilter.h"
+#include "LayoutEngine.h"
+#include "OpenTypeLayoutEngine.h"
+
+#include "GlyphSubstitutionTables.h"
+#include "GlyphDefinitionTables.h"
+#include "GlyphPositioningTables.h"
+
+U_NAMESPACE_BEGIN
+
+class MPreFixups;
+class LEGlyphStorage;
+
+/**
+ * This class implements OpenType layout for Indic OpenType fonts, as
+ * specified by Microsoft in "Creating and Supporting OpenType Fonts for
+ * Indic Scripts" (http://www.microsoft.com/typography/otspec/indicot/default.htm)
+ *
+ * This class overrides the characterProcessing method to do Indic character processing
+ * and reordering, and the glyphProcessing method to implement post-GSUB processing for
+ * left matras. (See the MS spec. for more details)
+ *
+ * @internal
+ */
+class IndicOpenTypeLayoutEngine : public OpenTypeLayoutEngine
+{
+public:
+    /**
+     * This is the main constructor. It constructs an instance of IndicOpenTypeLayoutEngine for
+     * a particular font, script and language. It takes the GSUB table as a parameter since
+     * LayoutEngine::layoutEngineFactory has to read the GSUB table to know that it has an
+     * Indic OpenType font.
+     *
+     * @param fontInstance - the font
+     * @param scriptCode - the script
+     * @param langaugeCode - the language
+     * @param gsubTable - the GSUB table
+     *
+     * @see LayoutEngine::layoutEngineFactory
+     * @see OpenTypeLayoutEngine
+     * @see ScriptAndLangaugeTags.h for script and language codes
+     *
+     * @internal
+     */
+    IndicOpenTypeLayoutEngine(const LEFontInstance *fontInstance, le_int32 scriptCode, le_int32 languageCode,
+                            le_int32 typoFlags, const GlyphSubstitutionTableHeader *gsubTable);
+
+    /**
+     * This constructor is used when the font requires a "canned" GSUB table which can't be known
+     * until after this constructor has been invoked.
+     *
+     * @param fontInstance - the font
+     * @param scriptCode - the script
+     * @param langaugeCode - the language
+     *
+     * @see OpenTypeLayoutEngine
+     * @see ScriptAndLangaugeTags.h for script and language codes
+     *
+     * @internal
+     */
+    IndicOpenTypeLayoutEngine(const LEFontInstance *fontInstance, le_int32 scriptCode, le_int32 languageCode,
+			      le_int32 typoFlags);
+
+    /**
+     * The destructor, virtual for correct polymorphic invocation.
+     *
+     * @internal
+     */
+   virtual ~IndicOpenTypeLayoutEngine();
+
+    /**
+     * ICU "poor man's RTTI", returns a UClassID for the actual class.
+     *
+     * @stable ICU 2.8
+     */
+    virtual UClassID getDynamicClassID() const;
+
+    /**
+     * ICU "poor man's RTTI", returns a UClassID for this class.
+     *
+     * @stable ICU 2.8
+     */
+    static UClassID getStaticClassID();
+
+protected:
+
+    /**
+     * This method does Indic OpenType character processing. It assigns the OpenType feature
+     * tags to the characters, and may generate output characters which have been reordered. For
+     * some Indic scripts, it may also split some vowels, resulting in more output characters
+     * than input characters.
+     *
+     * Input parameters:
+     * @param chars - the input character context
+     * @param offset - the index of the first character to process
+     * @param count - the number of characters to process
+     * @param max - the number of characters in the input context
+     * @param rightToLeft - <code>TRUE</code> if the characters are in a right to left directional run
+     * @param glyphStorage - the glyph storage object. The glyph and character index arrays will be set.
+     *                       the auxillary data array will be set to the feature tags.
+     *
+     * Output parameters:
+     * @param success - set to an error code if the operation fails
+     *
+     * @return the output character count
+     *
+     * @internal
+     */
+    virtual le_int32 characterProcessing(const LEUnicode chars[], le_int32 offset, le_int32 count, le_int32 max, le_bool rightToLeft,
+            LEUnicode *&outChars, LEGlyphStorage &glyphStorage, LEErrorCode &success);
+
+    /**
+     * This method does character to glyph mapping, applies the GSUB table and applies
+     * any post GSUB fixups for left matras. It calls OpenTypeLayoutEngine::glyphProcessing
+     * to do the character to glyph mapping, and apply the GSUB table.
+     *
+     * Note that in the case of "canned" GSUB tables, the output glyph indices may be
+     * "fake" glyph indices that need to be converted to "real" glyph indices by the
+     * glyphPostProcessing method.
+     *
+     * Input parameters:
+     * @param chars - the input character context
+     * @param offset - the index of the first character to process
+     * @param count - the number of characters to process
+     * @param max - the number of characters in the input context
+     * @param rightToLeft - <code>TRUE</code> if the characters are in a right to left directional run
+     * @param featureTags - the feature tag array
+     * @param glyphStorage - the glyph storage object. The glyph and char index arrays will be set.
+     *
+     * Output parameters:
+     * @param success - set to an error code if the operation fails
+     *
+     * @return the number of glyphs in the output glyph index array
+     *
+     * Note: if the character index array was already set by the characterProcessing
+     * method, this method won't change it.
+     *
+     * @internal
+     */
+    virtual le_int32 glyphProcessing(const LEUnicode chars[], le_int32 offset, le_int32 count, le_int32 max, le_bool rightToLeft,
+            LEGlyphStorage &glyphStorage, LEErrorCode &success);
+
+private:
+
+    MPreFixups *fMPreFixups;
+};
+
+U_NAMESPACE_END
+#endif
+