/*

*******************************************************************************

*

*   Copyright (C) 2002-2004, International Business Machines

*   Corporation and others.  All Rights Reserved.

*

*******************************************************************************

*   file name:  uenum.h

*   encoding:   US-ASCII

*   tab size:   8 (not used)

*   indentation:2

*

*   created on: 2002jul08

*   created by: Vladimir Weinstein

*/

#ifndef __UENUM_H

#define __UENUM_H

#include "unicode/utypes.h"

/**

 * An enumeration object.

 * For usage in C programs.

 * @stable ICU 2.2

 */

struct UEnumeration;

/** structure representing an enumeration object instance @stable ICU 2.2 */

typedef struct UEnumeration UEnumeration;

/**

 * Disposes of resources in use by the iterator.  If en is NULL,

 * does nothing.  After this call, any char* or UChar* pointer

 * returned by uenum_unext() or uenum_next() is invalid.

 * @param en UEnumeration structure pointer

 * @stable ICU 2.2

 */

U_STABLE void U_EXPORT2

uenum_close(UEnumeration* en);

/**

 * Returns the number of elements that the iterator traverses.  If

 * the iterator is out-of-sync with its service, status is set to

 * U_ENUM_OUT_OF_SYNC_ERROR.

 * This is a convenience function. It can end up being very

 * expensive as all the items might have to be pre-fetched (depending

 * on the type of data being traversed). Use with caution and only 

 * when necessary.

 * @param en UEnumeration structure pointer

 * @param status error code, can be U_ENUM_OUT_OF_SYNC_ERROR if the

 *               iterator is out of sync.

 * @return number of elements in the iterator

 * @stable ICU 2.2

 */

U_STABLE int32_t U_EXPORT2

uenum_count(UEnumeration* en, UErrorCode* status);

/**

 * Returns the next element in the iterator's list.  If there are

 * no more elements, returns NULL.  If the iterator is out-of-sync

 * with its service, status is set to U_ENUM_OUT_OF_SYNC_ERROR and

 * NULL is returned.  If the native service string is a char* string,

 * it is converted to UChar* with the invariant converter.

 * The result is terminated by (UChar)0.

 * @param en the iterator object

 * @param resultLength pointer to receive the length of the result

 *                     (not including the terminating \\0).

 *                     If the pointer is NULL it is ignored.

 * @param status the error code, set to U_ENUM_OUT_OF_SYNC_ERROR if

 *               the iterator is out of sync with its service.

 * @return a pointer to the string.  The string will be

 *         zero-terminated.  The return pointer is owned by this iterator

 *         and must not be deleted by the caller.  The pointer is valid

 *         until the next call to any uenum_... method, including

 *         uenum_next() or uenum_unext().  When all strings have been

 *         traversed, returns NULL.

 * @stable ICU 2.2

 */

U_STABLE const UChar* U_EXPORT2

uenum_unext(UEnumeration* en,

            int32_t* resultLength,

            UErrorCode* status);

/**

 * Returns the next element in the iterator's list.  If there are

 * no more elements, returns NULL.  If the iterator is out-of-sync

 * with its service, status is set to U_ENUM_OUT_OF_SYNC_ERROR and

 * NULL is returned.  If the native service string is a UChar*

 * string, it is converted to char* with the invariant converter.

 * The result is terminated by (char)0.  If the conversion fails

 * (because a character cannot be converted) then status is set to

 * U_INVARIANT_CONVERSION_ERROR and the return value is undefined

 * (but non-NULL).

 * @param en the iterator object

 * @param resultLength pointer to receive the length of the result

 *                     (not including the terminating \\0).

 *                     If the pointer is NULL it is ignored.

 * @param status the error code, set to U_ENUM_OUT_OF_SYNC_ERROR if

 *               the iterator is out of sync with its service.  Set to

 *               U_INVARIANT_CONVERSION_ERROR if the underlying native string is

 *               UChar* and conversion to char* with the invariant converter

 *               fails. This error pertains only to current string, so iteration

 *               might be able to continue successfully.

 * @return a pointer to the string.  The string will be

 *         zero-terminated.  The return pointer is owned by this iterator

 *         and must not be deleted by the caller.  The pointer is valid

 *         until the next call to any uenum_... method, including

 *         uenum_next() or uenum_unext().  When all strings have been

 *         traversed, returns NULL.

 * @stable ICU 2.2

 */

U_STABLE const char* U_EXPORT2

uenum_next(UEnumeration* en,

           int32_t* resultLength,

           UErrorCode* status);

/**

 * Resets the iterator to the current list of service IDs.  This

 * re-establishes sync with the service and rewinds the iterator

 * to start at the first element.

 * @param en the iterator object

 * @param status the error code, set to U_ENUM_OUT_OF_SYNC_ERROR if

 *               the iterator is out of sync with its service.  

 * @stable ICU 2.2

 */

U_STABLE void U_EXPORT2

uenum_reset(UEnumeration* en, UErrorCode* status);

#endif