Check in the pristine copy of ICU 4.6...

icu46/source/common/brkeng.h

+/**
+ ************************************************************************************
+ * Copyright (C) 2006-2007, International Business Machines Corporation and others. *
+ * All Rights Reserved.                                                             *
+ ************************************************************************************
+ */
+
+#ifndef BRKENG_H
+#define BRKENG_H
+
+#include "unicode/utypes.h"
+#include "unicode/uobject.h"
+#include "unicode/utext.h"
+#include "unicode/uscript.h"
+
+U_NAMESPACE_BEGIN
+
+class UnicodeSet;
+class UStack;
+class CompactTrieDictionary;
+
+/*******************************************************************
+ * LanguageBreakEngine
+ */
+
+/**
+ * <p>LanguageBreakEngines implement language-specific knowledge for
+ * finding text boundaries within a run of characters belonging to a
+ * specific set. The boundaries will be of a specific kind, e.g. word,
+ * line, etc.</p>
+ *
+ * <p>LanguageBreakEngines should normally be implemented so as to
+ * be shared between threads without locking.</p>
+ */
+class LanguageBreakEngine : public UMemory {
+ public:
+
+  /**
+   * <p>Default constructor.</p>
+   *
+   */
+  LanguageBreakEngine();
+
+  /**
+   * <p>Virtual destructor.</p>
+   */
+  virtual ~LanguageBreakEngine();
+
+ /**
+  * <p>Indicate whether this engine handles a particular character for
+  * a particular kind of break.</p>
+  *
+  * @param c A character which begins a run that the engine might handle
+  * @param breakType The type of text break which the caller wants to determine
+  * @return TRUE if this engine handles the particular character and break
+  * type.
+  */
+  virtual UBool handles(UChar32 c, int32_t breakType) const = 0;
+
+ /**
+  * <p>Find any breaks within a run in the supplied text.</p>
+  *
+  * @param text A UText representing the text. The
+  * iterator is left at the end of the run of characters which the engine
+  * is capable of handling.
+  * @param startPos The start of the run within the supplied text.
+  * @param endPos The end of the run within the supplied text.
+  * @param reverse Whether the caller is looking for breaks in a reverse
+  * direction.
+  * @param breakType The type of break desired, or -1.
+  * @param foundBreaks An allocated C array of the breaks found, if any
+  * @return The number of breaks found.
+  */
+  virtual int32_t findBreaks( UText *text,
+                              int32_t startPos,
+                              int32_t endPos,
+                              UBool reverse,
+                              int32_t breakType,
+                              UStack &foundBreaks ) const = 0;
+
+};
+
+/*******************************************************************
+ * LanguageBreakFactory
+ */
+
+/**
+ * <p>LanguageBreakFactorys find and return a LanguageBreakEngine
+ * that can determine breaks for characters in a specific set, if
+ * such an object can be found.</p>
+ *
+ * <p>If a LanguageBreakFactory is to be shared between threads,
+ * appropriate synchronization must be used; there is none internal
+ * to the factory.</p>
+ *
+ * <p>A LanguageBreakEngine returned by a LanguageBreakFactory can
+ * normally be shared between threads without synchronization, unless
+ * the specific subclass of LanguageBreakFactory indicates otherwise.</p>
+ *
+ * <p>A LanguageBreakFactory is responsible for deleting any LanguageBreakEngine
+ * it returns when it itself is deleted, unless the specific subclass of
+ * LanguageBreakFactory indicates otherwise. Naturally, the factory should
+ * not be deleted until the LanguageBreakEngines it has returned are no
+ * longer needed.</p>
+ */
+class LanguageBreakFactory : public UMemory {
+ public:
+
+  /**
+   * <p>Default constructor.</p>
+   *
+   */
+  LanguageBreakFactory();
+
+  /**
+   * <p>Virtual destructor.</p>
+   */
+  virtual ~LanguageBreakFactory();
+
+ /**
+  * <p>Find and return a LanguageBreakEngine that can find the desired
+  * kind of break for the set of characters to which the supplied
+  * character belongs. It is up to the set of available engines to
+  * determine what the sets of characters are.</p>
+  *
+  * @param c A character that begins a run for which a LanguageBreakEngine is
+  * sought.
+  * @param breakType The kind of text break for which a LanguageBreakEngine is
+  * sought.
+  * @return A LanguageBreakEngine with the desired characteristics, or 0.
+  */
+  virtual const LanguageBreakEngine *getEngineFor(UChar32 c, int32_t breakType) = 0;
+
+};
+
+/*******************************************************************
+ * UnhandledEngine
+ */
+
+/**
+ * <p>UnhandledEngine is a special subclass of LanguageBreakEngine that
+ * handles characters that no other LanguageBreakEngine is available to
+ * handle. It is told the character and the type of break; at its
+ * discretion it may handle more than the specified character (e.g.,
+ * the entire script to which that character belongs.</p>
+ *
+ * <p>UnhandledEngines may not be shared between threads without
+ * external synchronization.</p>
+ */
+
+class UnhandledEngine : public LanguageBreakEngine {
+ private:
+
+    /**
+     * The sets of characters handled, for each break type
+     * @internal
+     */
+
+  UnicodeSet    *fHandled[4];
+
+ public:
+
+  /**
+   * <p>Default constructor.</p>
+   *
+   */
+  UnhandledEngine(UErrorCode &status);
+
+  /**
+   * <p>Virtual destructor.</p>
+   */
+  virtual ~UnhandledEngine();
+
+ /**
+  * <p>Indicate whether this engine handles a particular character for
+  * a particular kind of break.</p>
+  *
+  * @param c A character which begins a run that the engine might handle
+  * @param breakType The type of text break which the caller wants to determine
+  * @return TRUE if this engine handles the particular character and break
+  * type.
+  */
+  virtual UBool handles(UChar32 c, int32_t breakType) const;
+
+ /**
+  * <p>Find any breaks within a run in the supplied text.</p>
+  *
+  * @param text A UText representing the text (TODO: UText). The
+  * iterator is left at the end of the run of characters which the engine
+  * is capable of handling.
+  * @param startPos The start of the run within the supplied text.
+  * @param endPos The end of the run within the supplied text.
+  * @param reverse Whether the caller is looking for breaks in a reverse
+  * direction.
+  * @param breakType The type of break desired, or -1.
+  * @param foundBreaks An allocated C array of the breaks found, if any
+  * @return The number of breaks found.
+  */
+  virtual int32_t findBreaks( UText *text,
+                              int32_t startPos,
+                              int32_t endPos,
+                              UBool reverse,
+                              int32_t breakType,
+                              UStack &foundBreaks ) const;
+
+ /**
+  * <p>Tell the engine to handle a particular character and break type.</p>
+  *
+  * @param c A character which the engine should handle
+  * @param breakType The type of text break for which the engine should handle c
+  */
+  virtual void handleCharacter(UChar32 c, int32_t breakType);
+
+};
+
+/*******************************************************************
+ * ICULanguageBreakFactory
+ */
+
+/**
+ * <p>ICULanguageBreakFactory is the default LanguageBreakFactory for
+ * ICU. It creates dictionary-based LanguageBreakEngines from dictionary
+ * data in the ICU data file.</p>
+ */
+class ICULanguageBreakFactory : public LanguageBreakFactory {
+ private:
+
+    /**
+     * The stack of break engines created by this factory
+     * @internal
+     */
+
+  UStack    *fEngines;
+
+ public:
+
+  /**
+   * <p>Standard constructor.</p>
+   *
+   */
+  ICULanguageBreakFactory(UErrorCode &status);
+
+  /**
+   * <p>Virtual destructor.</p>
+   */
+  virtual ~ICULanguageBreakFactory();
+
+ /**
+  * <p>Find and return a LanguageBreakEngine that can find the desired
+  * kind of break for the set of characters to which the supplied
+  * character belongs. It is up to the set of available engines to
+  * determine what the sets of characters are.</p>
+  *
+  * @param c A character that begins a run for which a LanguageBreakEngine is
+  * sought.
+  * @param breakType The kind of text break for which a LanguageBreakEngine is
+  * sought.
+  * @return A LanguageBreakEngine with the desired characteristics, or 0.
+  */
+  virtual const LanguageBreakEngine *getEngineFor(UChar32 c, int32_t breakType);
+
+ protected:
+
+ /**
+  * <p>Create a LanguageBreakEngine for the set of characters to which
+  * the supplied character belongs, for the specified break type.</p>
+  *
+  * @param c A character that begins a run for which a LanguageBreakEngine is
+  * sought.
+  * @param breakType The kind of text break for which a LanguageBreakEngine is
+  * sought.
+  * @return A LanguageBreakEngine with the desired characteristics, or 0.
+  */
+  virtual const LanguageBreakEngine *loadEngineFor(UChar32 c, int32_t breakType);
+
+ /**
+  * <p>Create a CompactTrieDictionary for the specified script and break type.</p>
+  *
+  * @param script An ISO 15924 script code that identifies the dictionary to be
+  * created.
+  * @param breakType The kind of text break for which a dictionary is
+  * sought.
+  * @return A CompactTrieDictionary with the desired characteristics, or 0.
+  */
+  virtual const CompactTrieDictionary *loadDictionaryFor(UScriptCode script, int32_t breakType);
+
+};
+
+U_NAMESPACE_END
+
+    /* BRKENG_H */
+#endif