icu/unicode/uenum.h

   1 /*
   2 *******************************************************************************
   3 *
   4 *   Copyright (C) 2002-2004, International Business Machines
   5 *   Corporation and others.  All Rights Reserved.
   6 *
   7 *******************************************************************************
   8 *   file name:  uenum.h
   9 *   encoding:   US-ASCII
  10 *   tab size:   8 (not used)
  11 *   indentation:2
  12 *
  13 *   created on: 2002jul08
  14 *   created by: Vladimir Weinstein
  15 */
  16
  17 #ifndef __UENUM_H
  18 #define __UENUM_H
  19
  20 #include "unicode/utypes.h"
  21
  22 /**
  23  * An enumeration object.
  24  * For usage in C programs.
  25  * @stable ICU 2.2
  26  */
  27 struct UEnumeration;
  28 /** structure representing an enumeration object instance @stable ICU 2.2 */
  29 typedef struct UEnumeration UEnumeration;
  30
  31 /**
  32  * Disposes of resources in use by the iterator.  If en is NULL,
  33  * does nothing.  After this call, any char* or UChar* pointer
  34  * returned by uenum_unext() or uenum_next() is invalid.
  35  * @param en UEnumeration structure pointer
  36  * @stable ICU 2.2
  37  */
  38 U_STABLE void U_EXPORT2
  39 uenum_close(UEnumeration* en);
  40
  41 /**
  42  * Returns the number of elements that the iterator traverses.  If
  43  * the iterator is out-of-sync with its service, status is set to
  44  * U_ENUM_OUT_OF_SYNC_ERROR.
  45  * This is a convenience function. It can end up being very
  46  * expensive as all the items might have to be pre-fetched (depending
  47  * on the type of data being traversed). Use with caution and only
  48  * when necessary.
  49  * @param en UEnumeration structure pointer
  50  * @param status error code, can be U_ENUM_OUT_OF_SYNC_ERROR if the
  51  *               iterator is out of sync.
  52  * @return number of elements in the iterator
  53  * @stable ICU 2.2
  54  */
  55 U_STABLE int32_t U_EXPORT2
  56 uenum_count(UEnumeration* en, UErrorCode* status);
  57
  58 /**
  59  * Returns the next element in the iterator's list.  If there are
  60  * no more elements, returns NULL.  If the iterator is out-of-sync
  61  * with its service, status is set to U_ENUM_OUT_OF_SYNC_ERROR and
  62  * NULL is returned.  If the native service string is a char* string,
  63  * it is converted to UChar* with the invariant converter.
  64  * The result is terminated by (UChar)0.
  65  * @param en the iterator object
  66  * @param resultLength pointer to receive the length of the result
  67  *                     (not including the terminating \\0).
  68  *                     If the pointer is NULL it is ignored.
  69  * @param status the error code, set to U_ENUM_OUT_OF_SYNC_ERROR if
  70  *               the iterator is out of sync with its service.
  71  * @return a pointer to the string.  The string will be
  72  *         zero-terminated.  The return pointer is owned by this iterator
  73  *         and must not be deleted by the caller.  The pointer is valid
  74  *         until the next call to any uenum_... method, including
  75  *         uenum_next() or uenum_unext().  When all strings have been
  76  *         traversed, returns NULL.
  77  * @stable ICU 2.2
  78  */
  79 U_STABLE const UChar* U_EXPORT2
  80 uenum_unext(UEnumeration* en,
  81             int32_t* resultLength,
  82             UErrorCode* status);
  83
  84 /**
  85  * Returns the next element in the iterator's list.  If there are
  86  * no more elements, returns NULL.  If the iterator is out-of-sync
  87  * with its service, status is set to U_ENUM_OUT_OF_SYNC_ERROR and
  88  * NULL is returned.  If the native service string is a UChar*
  89  * string, it is converted to char* with the invariant converter.
  90  * The result is terminated by (char)0.  If the conversion fails
  91  * (because a character cannot be converted) then status is set to
  92  * U_INVARIANT_CONVERSION_ERROR and the return value is undefined
  93  * (but non-NULL).
  94  * @param en the iterator object
  95  * @param resultLength pointer to receive the length of the result
  96  *                     (not including the terminating \\0).
  97  *                     If the pointer is NULL it is ignored.
  98  * @param status the error code, set to U_ENUM_OUT_OF_SYNC_ERROR if
  99  *               the iterator is out of sync with its service.  Set to
 100  *               U_INVARIANT_CONVERSION_ERROR if the underlying native string is
 101  *               UChar* and conversion to char* with the invariant converter
 102  *               fails. This error pertains only to current string, so iteration
 103  *               might be able to continue successfully.
 104  * @return a pointer to the string.  The string will be
 105  *         zero-terminated.  The return pointer is owned by this iterator
 106  *         and must not be deleted by the caller.  The pointer is valid
 107  *         until the next call to any uenum_... method, including
 108  *         uenum_next() or uenum_unext().  When all strings have been
 109  *         traversed, returns NULL.
 110  * @stable ICU 2.2
 111  */
 112 U_STABLE const char* U_EXPORT2
 113 uenum_next(UEnumeration* en,
 114            int32_t* resultLength,
 115            UErrorCode* status);
 116
 117 /**
 118  * Resets the iterator to the current list of service IDs.  This
 119  * re-establishes sync with the service and rewinds the iterator
 120  * to start at the first element.
 121  * @param en the iterator object
 122  * @param status the error code, set to U_ENUM_OUT_OF_SYNC_ERROR if
 123  *               the iterator is out of sync with its service.
 124  * @stable ICU 2.2
 125  */
 126 U_STABLE void U_EXPORT2
 127 uenum_reset(UEnumeration* en, UErrorCode* status);
 128
 129 #endif