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      1 //  2016 and later: Unicode, Inc. and others.
      2 // License & terms of use: http://www.unicode.org/copyright.html
      3 /*
      4 **********************************************************************
      5 *   Copyright (C) 1999-2011, International Business Machines
      6 *   Corporation and others.  All Rights Reserved.
      7 **********************************************************************
      8 *
      9 * File USC_IMPL.H
     10 *
     11 * Modification History:
     12 *
     13 *   Date        Name        Description
     14 *   07/08/2002  Eric Mader  Creation.
     15 ******************************************************************************
     16 */
     17 
     18 #ifndef USC_IMPL_H
     19 #define USC_IMPL_H
     20 #include "unicode/utypes.h"
     21 #include "unicode/uscript.h"
     22 
     23 /**
     24  * <code>UScriptRun</code> is used to find runs of characters in
     25  * the same script. It implements a simple iterator over an array
     26  * of characters. The iterator will resolve script-neutral characters
     27  * like punctuation into the script of the surrounding characters.
     28  *
     29  * The iterator will try to match paired punctuation. If it sees an
     30  * opening punctuation character, it will remember the script that
     31  * was assigned to that character, and assign the same script to the
     32  * matching closing punctuation.
     33  *
     34  * Scripts are chosen based on the <code>UScriptCode</code> enumeration.
     35  * No attempt is made to combine related scripts into a single run. In
     36  * particular, Hiragana, Katakana, and Han characters will appear in seperate
     37  * runs.
     38 
     39  * Here is an example of how to iterate over script runs:
     40  * <pre>
     41  * \code
     42  * void printScriptRuns(const UChar *text, int32_t length)
     43  * {
     44  *     UErrorCode error = U_ZERO_ERROR;
     45  *     UScriptRun *scriptRun = uscript_openRun(text, testLength, &error);
     46  *     int32_t start = 0, limit = 0;
     47  *     UScriptCode code = USCRIPT_INVALID_CODE;
     48  *
     49  *     while (uscript_nextRun(&start, &limit, &code)) {
     50  *         printf("Script '%s' from %d to %d.\n", uscript_getName(code), start, limit);
     51  *     }
     52  *
     53  *     uscript_closeRun(scriptRun);
     54  *  }
     55  * </pre>
     56  */
     57 struct UScriptRun;
     58 
     59 typedef struct UScriptRun UScriptRun;
     60 
     61 /**
     62  * Create a <code>UScriptRun</code> object for iterating over the given text. This object must
     63  * be freed using <code>uscript_closeRun()</code>. Note that this object does not copy the source text,
     64  * only the pointer to it. You must make sure that the pointer remains valid until you call
     65  * <code>uscript_closeRun()</code> or <code>uscript_setRunText()</code>.
     66  *
     67  * @param src is the address of the array of characters over which to iterate.
     68  *        if <code>src == NULL</code> and <code>length == 0</code>,
     69  *        an empty <code>UScriptRun</code> object will be returned.
     70  *
     71  * @param length is the number of characters over which to iterate.
     72  *
     73  * @param pErrorCode is a pointer to a valid <code>UErrorCode</code> value. If this value
     74  *        indicates a failure on entry, the function will immediately return.
     75  *        On exit the value will indicate the success of the operation.
     76  *
     77  * @return the address of <code>UScriptRun</code> object which will iterate over the text,
     78  *         or <code>NULL</code> if the operation failed.
     79  */
     80 U_CAPI UScriptRun * U_EXPORT2
     81 uscript_openRun(const UChar *src, int32_t length, UErrorCode *pErrorCode);
     82 
     83 /**
     84  * Frees the given <code>UScriptRun</code> object and any storage associated with it.
     85  * On return, scriptRun no longer points to a valid <code>UScriptRun</code> object.
     86  *
     87  * @param scriptRun is the <code>UScriptRun</code> object which will be freed.
     88  */
     89 U_CAPI void U_EXPORT2
     90 uscript_closeRun(UScriptRun *scriptRun);
     91 
     92 /**
     93  * Reset the <code>UScriptRun</code> object so that it will start iterating from
     94  * the beginning.
     95  *
     96  * @param scriptRun is the address of the <code>UScriptRun</code> object to be reset.
     97  */
     98 U_CAPI void U_EXPORT2
     99 uscript_resetRun(UScriptRun *scriptRun);
    100 
    101 /**
    102  * Change the text over which the given <code>UScriptRun</code> object iterates.
    103  *
    104  * @param scriptRun is the <code>UScriptRun</code> object which will be changed.
    105  *
    106  * @param src is the address of the new array of characters over which to iterate.
    107  *        If <code>src == NULL</code> and <code>length == 0</code>,
    108  *        the <code>UScriptRun</code> object will become empty.
    109  *
    110  * @param length is the new number of characters over which to iterate
    111  *
    112  * @param pErrorCode is a pointer to a valid <code>UErrorCode</code> value. If this value
    113  *        indicates a failure on entry, the function will immediately return.
    114  *        On exit the value will indicate the success of the operation.
    115  */
    116 U_CAPI void U_EXPORT2
    117 uscript_setRunText(UScriptRun *scriptRun, const UChar *src, int32_t length, UErrorCode *pErrorCode);
    118 
    119 /**
    120  * Advance the <code>UScriptRun</code> object to the next script run, return the start and limit
    121  * offsets, and the script of the run.
    122  *
    123  * @param scriptRun is the address of the <code>UScriptRun</code> object.
    124  *
    125  * @param pRunStart is a pointer to the variable to receive the starting offset of the next run.
    126  *        This pointer can be <code>NULL</code> if the value is not needed.
    127  *
    128  * @param pRunLimit is a pointer to the variable to receive the limit offset of the next run.
    129  *        This pointer can be <code>NULL</code> if the value is not needed.
    130  *
    131  * @param pRunScript is a pointer to the variable to receive the UScriptCode for the
    132  *        script of the current run. This pointer can be <code>NULL</code> if the value is not needed.
    133  *
    134  * @return true if there was another script run.
    135  */
    136 U_CAPI UBool U_EXPORT2
    137 uscript_nextRun(UScriptRun *scriptRun, int32_t *pRunStart, int32_t *pRunLimit, UScriptCode *pRunScript);
    138 
    139 #endif
    140