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      1 //  2018 and later: Unicode, Inc. and others.
      2 // License & terms of use: http://www.unicode.org/copyright.html
      3 
      4 // ucpmap.h
      5 // created: 2018sep03 Markus W. Scherer
      6 
      7 #ifndef __UCPMAP_H__
      8 #define __UCPMAP_H__
      9 
     10 #include "unicode/utypes.h"
     11 
     12 #ifndef U_HIDE_DRAFT_API
     13 
     14 U_CDECL_BEGIN
     15 
     16 /**
     17  * \file
     18  *
     19  * This file defines an abstract map from Unicode code points to integer values.
     20  *
     21  * @see UCPMap
     22  * @see UCPTrie
     23  * @see UMutableCPTrie
     24  */
     25 
     26 /**
     27  * Abstract map from Unicode code points (U+0000..U+10FFFF) to integer values.
     28  *
     29  * @see UCPTrie
     30  * @see UMutableCPTrie
     31  * @draft ICU 63
     32  */
     33 typedef struct UCPMap UCPMap;
     34 
     35 /**
     36  * Selectors for how ucpmap_getRange() etc. should report value ranges overlapping with surrogates.
     37  * Most users should use UCPMAP_RANGE_NORMAL.
     38  *
     39  * @see ucpmap_getRange
     40  * @see ucptrie_getRange
     41  * @see umutablecptrie_getRange
     42  * @draft ICU 63
     43  */
     44 enum UCPMapRangeOption {
     45     /**
     46      * ucpmap_getRange() enumerates all same-value ranges as stored in the map.
     47      * Most users should use this option.
     48      * @draft ICU 63
     49      */
     50     UCPMAP_RANGE_NORMAL,
     51     /**
     52      * ucpmap_getRange() enumerates all same-value ranges as stored in the map,
     53      * except that lead surrogates (U+D800..U+DBFF) are treated as having the
     54      * surrogateValue, which is passed to getRange() as a separate parameter.
     55      * The surrogateValue is not transformed via filter().
     56      * See U_IS_LEAD(c).
     57      *
     58      * Most users should use UCPMAP_RANGE_NORMAL instead.
     59      *
     60      * This option is useful for maps that map surrogate code *units* to
     61      * special values optimized for UTF-16 string processing
     62      * or for special error behavior for unpaired surrogates,
     63      * but those values are not to be associated with the lead surrogate code *points*.
     64      * @draft ICU 63
     65      */
     66     UCPMAP_RANGE_FIXED_LEAD_SURROGATES,
     67     /**
     68      * ucpmap_getRange() enumerates all same-value ranges as stored in the map,
     69      * except that all surrogates (U+D800..U+DFFF) are treated as having the
     70      * surrogateValue, which is passed to getRange() as a separate parameter.
     71      * The surrogateValue is not transformed via filter().
     72      * See U_IS_SURROGATE(c).
     73      *
     74      * Most users should use UCPMAP_RANGE_NORMAL instead.
     75      *
     76      * This option is useful for maps that map surrogate code *units* to
     77      * special values optimized for UTF-16 string processing
     78      * or for special error behavior for unpaired surrogates,
     79      * but those values are not to be associated with the lead surrogate code *points*.
     80      * @draft ICU 63
     81      */
     82     UCPMAP_RANGE_FIXED_ALL_SURROGATES
     83 };
     84 #ifndef U_IN_DOXYGEN
     85 typedef enum UCPMapRangeOption UCPMapRangeOption;
     86 #endif
     87 
     88 /**
     89  * Returns the value for a code point as stored in the map, with range checking.
     90  * Returns an implementation-defined error value if c is not in the range 0..U+10FFFF.
     91  *
     92  * @param map the map
     93  * @param c the code point
     94  * @return the map value,
     95  *         or an implementation-defined error value if the code point is not in the range 0..U+10FFFF
     96  * @draft ICU 63
     97  */
     98 U_CAPI uint32_t U_EXPORT2
     99 ucpmap_get(const UCPMap *map, UChar32 c);
    100 
    101 /**
    102  * Callback function type: Modifies a map value.
    103  * Optionally called by ucpmap_getRange()/ucptrie_getRange()/umutablecptrie_getRange().
    104  * The modified value will be returned by the getRange function.
    105  *
    106  * Can be used to ignore some of the value bits,
    107  * make a filter for one of several values,
    108  * return a value index computed from the map value, etc.
    109  *
    110  * @param context an opaque pointer, as passed into the getRange function
    111  * @param value a value from the map
    112  * @return the modified value
    113  * @draft ICU 63
    114  */
    115 typedef uint32_t U_CALLCONV
    116 UCPMapValueFilter(const void *context, uint32_t value);
    117 
    118 /**
    119  * Returns the last code point such that all those from start to there have the same value.
    120  * Can be used to efficiently iterate over all same-value ranges in a map.
    121  * (This is normally faster than iterating over code points and get()ting each value,
    122  * but much slower than a data structure that stores ranges directly.)
    123  *
    124  * If the UCPMapValueFilter function pointer is not NULL, then
    125  * the value to be delivered is passed through that function, and the return value is the end
    126  * of the range where all values are modified to the same actual value.
    127  * The value is unchanged if that function pointer is NULL.
    128  *
    129  * Example:
    130  * \code
    131  * UChar32 start = 0, end;
    132  * uint32_t value;
    133  * while ((end = ucpmap_getRange(map, start, UCPMAP_RANGE_NORMAL, 0,
    134  *                               NULL, NULL, &value)) >= 0) {
    135  *     // Work with the range start..end and its value.
    136  *     start = end + 1;
    137  * }
    138  * \endcode
    139  *
    140  * @param map the map
    141  * @param start range start
    142  * @param option defines whether surrogates are treated normally,
    143  *               or as having the surrogateValue; usually UCPMAP_RANGE_NORMAL
    144  * @param surrogateValue value for surrogates; ignored if option==UCPMAP_RANGE_NORMAL
    145  * @param filter a pointer to a function that may modify the map data value,
    146  *     or NULL if the values from the map are to be used unmodified
    147  * @param context an opaque pointer that is passed on to the filter function
    148  * @param pValue if not NULL, receives the value that every code point start..end has;
    149  *     may have been modified by filter(context, map value)
    150  *     if that function pointer is not NULL
    151  * @return the range end code point, or -1 if start is not a valid code point
    152  * @draft ICU 63
    153  */
    154 U_CAPI UChar32 U_EXPORT2
    155 ucpmap_getRange(const UCPMap *map, UChar32 start,
    156                 UCPMapRangeOption option, uint32_t surrogateValue,
    157                 UCPMapValueFilter *filter, const void *context, uint32_t *pValue);
    158 
    159 U_CDECL_END
    160 
    161 #endif  // U_HIDE_DRAFT_API
    162 #endif
    163