Check in the pristine copy of ICU 4.6...

icu46/source/i18n/unicode/bmsearch.h

+/*
+ ******************************************************************************
+ *   Copyright (C) 1996-2010, International Business Machines                 *
+ *   Corporation and others.  All Rights Reserved.                            *
+ ******************************************************************************
+ */
+
+/**
+ * \file 
+ * \brief C++ API: Boyer-Moore StringSearch technology preview
+ * \internal ICU 4.0.1 technology preview
+ */
+ 
+#ifndef B_M_SEARCH_H
+#define B_M_SEARCH_H
+
+#include "unicode/utypes.h"
+
+#if !UCONFIG_NO_COLLATION && !UCONFIG_NO_BREAK_ITERATION
+
+#include "unicode/uobject.h"
+#include "unicode/ucol.h"
+
+#include "unicode/colldata.h"
+
+U_NAMESPACE_BEGIN
+
+class BadCharacterTable;
+class GoodSuffixTable;
+class Target;
+
+/**
+ * BoyerMooreSearch
+ *
+ * This object holds the information needed to do a Collation sensitive Boyer-Moore search. It encapulates
+ * the pattern, the "bad character" and "good suffix" tables, the Collator-based data needed to compute them,
+ * and a reference to the text being searched.
+ *
+ * To do a search, you fist need to get a <code>CollData</code> object by calling <code>CollData::open</code>.
+ * Then you construct a <code>BoyerMooreSearch</code> object from the <code>CollData</code> object, the pattern
+ * string and the target string. Then you call the <code>search</code> method. Here's a code sample:
+ *
+ * <pre>
+ * void boyerMooreExample(UCollator *collator, UnicodeString *pattern, UnicodeString *target)
+ * {
+ *     UErrorCode status = U_ZERO_ERROR;
+ *     CollData *collData = CollData::open(collator, status);
+ *
+ *     if (U_FAILURE(status)) {
+ *         // could not create a CollData object
+ *         return;
+ *     }
+ *
+ *     BoyerMooreSearch *search = new BoyerMooreSearch(collData, *patternString, target, status);
+ *
+ *     if (U_FAILURE(status)) {
+ *         // could not create a BoyerMooreSearch object
+ *         CollData::close(collData);
+ *         return;
+ *     }
+ *
+ *     int32_t offset = 0, start = -1, end = -1;
+ *
+ *     // Find all matches
+ *     while (search->search(offset, start, end)) {
+ *         // process the match between start and end
+ *         ...
+ *         // advance past the match
+ *         offset = end; 
+ *     }
+ *
+ *     // at this point, if offset == 0, there were no matches
+ *     if (offset == 0) {
+ *         // handle the case of no matches
+ *     }
+ *
+ *     delete search;
+ *     CollData::close(collData);
+ *
+ *     // CollData objects are cached, so the call to
+ *     // CollData::close doesn't delete the object.
+ *     // Call this if you don't need the object any more.
+ *     CollData::flushCollDataCache();
+ * }
+ * </pre>
+ *
+ * NOTE: This is a technology preview. The final version of this API may not bear any resenblence to this API.
+ *
+ * Knows linitations:
+ *   1) Backwards searching has not been implemented.
+ *
+ *   2) For Han and Hangul characters, this code ignores any Collation tailorings. In general,
+ *      this isn't a problem, but in Korean locals, at strength 1, Hangul characters are tailored
+ *      to be equal to Han characters with the same pronounciation. Because this code ignroes
+ *      tailorings, searching for a Hangul character will not find a Han character and visa-versa.
+ *
+ *   3) In some cases, searching for a pattern that needs to be normalized and ends
+ *      in a discontiguous contraction may fail. The only known cases of this are with
+ *      the Tibetan script. For example searching for the pattern
+ *      "\u0F7F\u0F80\u0F81\u0F82\u0F83\u0F84\u0F85" will fail. (This case is artificial. We've
+ *      been unable to find a pratical, real-world example of this failure.)  
+ *
+ * @internal ICU 4.0.1 technology preview
+ *
+ * @see CollData
+ */
+class U_I18N_API BoyerMooreSearch : public UObject
+{
+public:
+    /**
+     * Construct a <code>BoyerMooreSearch</code> object.
+     *
+     * @param theData - A <code>CollData</code> object holding the Collator-sensitive data
+     * @param patternString - the string for which to search
+     * @param targetString - the string in which to search or <code>NULL</code> if youu will
+     *                       set it later by calling <code>setTargetString</code>.
+     * @param status - will be set if any errors occur. 
+     *
+     * Note: if on return, status is set to an error code,
+     * the only safe thing to do with this object is to call
+     * the destructor.
+     *
+     * @internal ICU 4.0.1 technology preview
+     */
+    BoyerMooreSearch(CollData *theData, const UnicodeString &patternString, const UnicodeString *targetString, UErrorCode &status);
+
+    /**
+     * The desstructor
+     *
+     * @internal ICU 4.0.1 technology preview
+     */
+    ~BoyerMooreSearch();
+
+    /**
+     * Test the pattern to see if it generates any CEs.
+     *
+     * @return <code>TRUE</code> if the pattern string did not generate any CEs
+     *
+     * @internal ICU 4.0.1 technology preview
+     */
+    UBool empty();
+
+    /**
+     * Search for the pattern string in the target string.
+     *
+     * @param offset - the offset in the target string at which to begin the search
+     * @param start - will be set to the starting offset of the match, or -1 if there's no match
+     * @param end - will be set to the ending offset of the match, or -1 if there's no match
+     *
+     * @return <code>TRUE</code> if the match succeeds, <code>FALSE</code> otherwise.
+     *
+     * @internal ICU 4.0.1 technology preview
+     */
+    UBool search(int32_t offset, int32_t &start, int32_t &end);
+
+    /**
+     * Set the target string for the match.
+     *
+     * @param targetString - the new target string
+     * @param status - will be set if any errors occur. 
+     *
+     * @internal ICU 4.0.1 technology preview
+     */
+    void setTargetString(const UnicodeString *targetString, UErrorCode &status);
+
+    // **** no longer need these? ****
+    /**
+     * Return the <code>CollData</code> object used for searching
+     *
+     * @return the <code>CollData</code> object used for searching
+     *
+     * @internal ICU 4.0.1 technology preview
+     */
+    CollData *getData();
+
+    /**
+     * Return the CEs generated by the pattern string.
+     *
+     * @return a <code>CEList</code> object holding the CEs generated by the pattern string.
+     *
+     * @internal ICU 4.0.1 technology preview
+     */
+    CEList   *getPatternCEs();
+
+    /**
+     * Return the <code>BadCharacterTable</code> object computed for the pattern string.
+     *
+     * @return the <code>BadCharacterTable</code> object.
+     *
+     * @internal ICU 4.0.1 technology preview
+     */
+    BadCharacterTable *getBadCharacterTable();
+
+    /**
+     * Return the <code>GoodSuffixTable</code> object computed for the pattern string.
+     *
+     * @return the <code>GoodSuffixTable</code> object computed for the pattern string.
+     *
+     * @internal ICU 4.0.1 technology preview
+     */
+    GoodSuffixTable   *getGoodSuffixTable();
+
+    /**
+     * UObject glue...
+     * @internal ICU 4.0.1 technology preview
+     */
+    virtual UClassID getDynamicClassID() const;
+    /**
+     * UObject glue...
+     * @internal ICU 4.0.1 technology preview
+     */
+    static UClassID getStaticClassID();
+    
+private:
+    CollData *data;
+    CEList *patCEs;
+    BadCharacterTable *badCharacterTable;
+    GoodSuffixTable   *goodSuffixTable;
+    UnicodeString pattern;
+    Target *target;
+};
+
+U_NAMESPACE_END
+
+#endif // #if !UCONFIG_NO_COLLATION
+#endif // #ifndef B_M_SEARCH_H