ICU-6.2.15.tar.gz

[apple/icu.git] / icuSources / i18n / usrchimp.h

/*
**********************************************************************
*   Copyright (C) 2001-2004 IBM and others. All rights reserved.
**********************************************************************
*   Date        Name        Description
*  08/13/2001   synwee      Creation.
**********************************************************************
*/
#ifndef USRCHIMP_H
#define USRCHIMP_H

#include "unicode/utypes.h"

#if !UCONFIG_NO_COLLATION

#include "unicode/ucol.h"
#include "unicode/ucoleitr.h"
#include "unicode/ubrk.h"

#define INITIAL_ARRAY_SIZE_       256
#define MAX_TABLE_SIZE_           257

struct USearch {
    // required since collation element iterator does not have a getText API
    const UChar              *text;
          int32_t             textLength; // exact length
          UBool               isOverlap;
          UBool               isCanonicalMatch;
          UBreakIterator     *breakIter;
    // value USEARCH_DONE is the default value
    // if we are not at the start of the text or the end of the text, 
    // depending on the iteration direction and matchedIndex is USEARCH_DONE 
    // it means that we can find any more matches in that particular direction
          int32_t         matchedIndex; 
          int32_t             matchedLength;
          UBool               isForwardSearching;
          UBool               reset;
};

struct UPattern {
    const UChar              *text;
          int32_t             textLength; // exact length
          // length required for backwards ce comparison
          int32_t             CELength; 
          int32_t            *CE;
          int32_t             CEBuffer[INITIAL_ARRAY_SIZE_];
          UBool               hasPrefixAccents;
          UBool               hasSuffixAccents;
          int16_t             defaultShiftSize;
          int16_t             shift[MAX_TABLE_SIZE_];
          int16_t             backShift[MAX_TABLE_SIZE_];
};

struct UStringSearch {
    struct USearch            *search;
    struct UPattern            pattern;
    const  UCollator          *collator;
    // positions within the collation element iterator is used to determine
    // if we are at the start of the text.
           UCollationElements *textIter;
    // utility collation element, used throughout program for temporary 
    // iteration.
           UCollationElements *utilIter;
           UBool               ownCollator;
           UCollationStrength  strength;
           uint32_t            ceMask;
           uint32_t            variableTop;
           UBool               toShift;
           UChar               canonicalPrefixAccents[INITIAL_ARRAY_SIZE_];
           UChar               canonicalSuffixAccents[INITIAL_ARRAY_SIZE_];
};

/**
* Exact matches without checking for the ends for extra accents.
* The match after the position within the collation element iterator is to be
* found. 
* After a match is found the offset in the collation element iterator will be
* shifted to the start of the match.
* Implementation note: 
* For tertiary we can't use the collator->tertiaryMask, that is a 
* preprocessed mask that takes into account case options. since we are only 
* concerned with exact matches, we don't need that.
* Alternate handling - since only the 16 most significant digits is only used, 
* we can safely do a compare without masking if the ce is a variable, we mask 
* and get only the primary values no shifting to quartenary is required since 
* all primary values less than variabletop will need to be masked off anyway.
* If the end character is composite and the pattern ce does not match the text 
* ce, we skip it until we find a match in the end composite character or when 
* it has passed the character. This is so that we can match pattern "a" with
* the text "\u00e6" 
* @param strsrch string search data
* @param status error status if any
* @return TRUE if an exact match is found, FALSE otherwise
*/
U_CFUNC
UBool usearch_handleNextExact(UStringSearch *strsrch, UErrorCode *status);

/**
* Canonical matches.
* According to the definition, matches found here will include the whole span 
* of beginning and ending accents if it overlaps that region.
* @param strsrch string search data
* @param status error status if any
* @return TRUE if a canonical match is found, FALSE otherwise
*/
U_CFUNC
UBool usearch_handleNextCanonical(UStringSearch *strsrch, UErrorCode *status);

/**
* Gets the previous match.
* Comments follows from handleNextExact
* @param strsrch string search data
* @param status error status if any
* @return True if a exact math is found, FALSE otherwise.
*/
U_CFUNC
UBool usearch_handlePreviousExact(UStringSearch *strsrch, UErrorCode *status);

/**
* Canonical matches.
* According to the definition, matches found here will include the whole span 
* of beginning and ending accents if it overlaps that region.
* @param strsrch string search data
* @param status error status if any
* @return TRUE if a canonical match is found, FALSE otherwise
*/
U_CFUNC
UBool usearch_handlePreviousCanonical(UStringSearch *strsrch, 
                                      UErrorCode    *status);

#endif /* #if !UCONFIG_NO_COLLATION */

#endif