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Diffstat (limited to 'intl/icu/source/i18n/unicode/bms.h')
| -rw-r--r-- | intl/icu/source/i18n/unicode/bms.h | 280 |
1 files changed, 280 insertions, 0 deletions
diff --git a/intl/icu/source/i18n/unicode/bms.h b/intl/icu/source/i18n/unicode/bms.h new file mode 100644 index 0000000..3310248 --- /dev/null +++ b/intl/icu/source/i18n/unicode/bms.h @@ -0,0 +1,280 @@ +/* + * Copyright (C) 1996-2012, International Business Machines Corporation and Others. + * All rights reserved. + */ + +/** + * \file + * \brief C API: Boyer-Moore StringSearch prototype. + * \internal + */ + +#ifndef _BMS_H +#define _BMS_H + +#include "unicode/utypes.h" + +#if !UCONFIG_NO_COLLATION && !UCONFIG_NO_BREAK_ITERATION + +#include "unicode/ucol.h" + +#ifndef U_HIDE_INTERNAL_API + +/** + * A <code>UCD</code> object holds the Collator-specific data needed to + * compute the length of the shortest string that can + * generate a partcular list of CEs. + * + * <code>UCD</code> objects are quite expensive to compute. Because + * of this, they are cached. When you call <code>ucd_open</code> it + * returns a reference counted cached object. When you call <code>ucd_close</code> + * the reference count on the object is decremented but the object is not deleted. + * + * If you do not need to reuse any unreferenced objects in the cache, you can call + * <code>ucd_flushCCache</code>. If you no longer need any <code>UCD</code> + * objects, you can call <code>ucd_freeCache</code> + * + * @internal ICU 4.0.1 technology preview + */ +typedef void UCD; + +/** + * Open a <code>UCD</code> object. + * + * @param coll - the collator + * @param status - will be set if any errors occur. + * + * @return the <code>UCD</code> object. You must call + * <code>ucd_close</code> when you are done using the object. + * + * Note: if on return status is set to an error, the only safe + * thing to do with the returned object is to call <code>ucd_close</code>. + * + * @internal ICU 4.0.1 technology preview + */ +U_INTERNAL UCD * U_EXPORT2 +ucd_open(UCollator *coll, UErrorCode *status); + +/** + * Release a <code>UCD</code> object. + * + * @param ucd - the object + * + * @internal ICU 4.0.1 technology preview + */ +U_INTERNAL void U_EXPORT2 +ucd_close(UCD *ucd); + +/** + * Get the <code>UCollator</code> object used to create a <code>UCD</code> object. + * The <code>UCollator</code> object returned may not be the exact + * object that was used to create this object, but it will have the + * same behavior. + * + * @param ucd - the <code>UCD</code> object + * + * @return the <code>UCollator</code> used to create the given + * <code>UCD</code> object. + * + * @internal ICU 4.0.1 technology preview + */ +U_INTERNAL UCollator * U_EXPORT2 +ucd_getCollator(UCD *ucd); + +/** + * <code>UCD</code> objects are expensive to compute, and so + * may be cached. This routine will free the cached objects and delete + * the cache. + * + * WARNING: Don't call this until you are have called <code>close</code> + * for each <code>UCD</code> object that you have used. also, + * DO NOT call this if another thread may be calling <code>ucd_flushCache</code> + * at the same time. + * + * @internal ICU 4.0.1 technology preview + */ +U_INTERNAL void U_EXPORT2 +ucd_freeCache(); + +/** + * <code>UCD</code> objects are expensive to compute, and so + * may be cached. This routine will remove any unused <code>UCD</code> + * objects from the cache. + * + * @internal 4.0.1 technology preview + */ +U_INTERNAL void U_EXPORT2 +ucd_flushCache(); + +/** + * BMS + * + * 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 first need to get a <code>UCD</code> object by calling <code>ucd_open</code>. + * Then you construct a <code>BMS</code> object from the <code>UCD</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, UChar *pattern, int32_t patternLen, UChar *target, int32_t targetLength) + * { + * UErrorCode status = U_ZERO_ERROR; + * int32_t offset = 0, start = -1, end = -1; + * UCD *ucd = NULL); + * BMS *bms = NULL; + * + * ucd = ucd_open(collator, &status); + * if (U_FAILURE(status)) { + * // could not create a UCD object + * return; + * } + * + * BMS *bms = bms_open(ucd, pattern, patternLength, target, targetlength, &status); + * if (U_FAILURE(status)) { + * // could not create a BMS object + * ucd_close(ucd); + * return; + * } + * + * + * // Find all matches + * while (bms_search(bms, 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 + * } + * + * bms_close(bms); + * ucd_close(ucd); + * + * // UCD objects are cached, so the call to + * // ucd_close doesn't delete the object. + * // Call this if you don't need the object any more. + * ucd_flushCache(); + * } + * </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.) + * + * NOTE: This is a technology preview. The final version of this API may not bear any resenblence to this API. + * + * @internal ICU 4.0.1 technology preview + */ +struct BMS; +typedef struct BMS BMS; /**< @see BMS */ + +/** + * Construct a <code>MBS</code> object. + * + * @param ucd - A <code>UCD</code> object holding the Collator-sensitive data + * @param pattern - the string for which to search + * @param patternLength - the length of the string for which to search + * @param target - the string in which to search + * @param targetLength - the length of the string in which to search + * @param status - will be set if any errors occur. + * + * @return the <code>BMS</code> object. + * + * Note: if on return status is set to an error, the only safe + * thing to do with the returned object is to call + * <code>bms_close</code>. + * + * @internal ICU 4.0.1 technology preview + */ +U_INTERNAL BMS * U_EXPORT2 +bms_open(UCD *ucd, + const UChar *pattern, int32_t patternLength, + const UChar *target, int32_t targetLength, + UErrorCode *status); + +/** + * Close a <code>BMS</code> object and release all the + * storage associated with it. + * + * @param bms - the <code>BMS</code> object to close. + * @internal ICU 4.0.1 technology preview + */ +U_INTERNAL void U_EXPORT2 +bms_close(BMS *bms); + +/** + * Test the pattern to see if it generates any CEs. + * + * @param bms - the <code>BMS</code> object + * @return <code>TRUE</code> if the pattern string did not generate any CEs + * + * @internal ICU 4.0.1 technology preview + */ +U_INTERNAL UBool U_EXPORT2 +bms_empty(BMS *bms); + +/** + * Get the <code>UCD</code> object used to create + * a given <code>BMS</code> object. + * + * @param bms - the <code>BMS</code> object + * + * @return - the <code>UCD</code> object used to create + * the given <code>BMS</code> object. + * + * @internal ICU 4.0.1 technology preview + */ +U_INTERNAL UCD * U_EXPORT2 +bms_getData(BMS *bms); + +/** + * Search for the pattern string in the target string. + * + * @param bms - the <code>BMS</code> object + * @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 + */ +U_INTERNAL UBool U_EXPORT2 +bms_search(BMS *bms, int32_t offset, int32_t *start, int32_t *end); + +/** + * Set the target string for the match. + * + * @param bms - the <code>BMS</code> object + * @param target - the new target string + * @param targetLength - the length of the new target string + * @param status - will be set if any errors occur. + * + * @internal ICU 4.0.1 technology preview + */ +U_INTERNAL void U_EXPORT2 +bms_setTargetString(BMS *bms, const UChar *target, int32_t targetLength, UErrorCode *status); + +#endif /* U_HIDE_INTERNAL_API */ + +#endif + +#endif /* _BMS_H */ |