icuSources/common/usc_impl.h

   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