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      1 /*
      2 **********************************************************************
      3 * Copyright (c) 2003-2004, International Business Machines
      4 * Corporation and others.  All Rights Reserved.
      5 **********************************************************************
      6 * Author: Alan Liu
      7 * Created: March 19 2003
      8 * Since: ICU 2.6
      9 **********************************************************************
     10 */
     11 #ifndef UCAT_H
     12 #define UCAT_H
     13 
     14 #include "unicode/utypes.h"
     15 #include "unicode/ures.h"
     16 
     17 /**
     18  * \file
     19  * \brief C API: Message Catalog Wrappers
     20  *
     21  * This C API provides look-alike functions that deliberately resemble
     22  * the POSIX catopen, catclose, and catgets functions.  The underlying
     23  * implementation is in terms of ICU resource bundles, rather than
     24  * POSIX message catalogs.
     25  *
     26  * The ICU resource bundles obey standard ICU inheritance policies.
     27  * To facilitate this, sets and messages are flattened into one tier.
     28  * This is done by creating resource bundle keys of the form
     29  * <set_num>%<msg_num> where set_num is the set number and msg_num is
     30  * the message number, formatted as decimal strings.
     31  *
     32  * Example:  Consider a message catalog containing two sets:
     33  *
     34  * Set 1: Message 4  = "Good morning."
     35  *        Message 5  = "Good afternoon."
     36  *        Message 7  = "Good evening."
     37  *        Message 8  = "Good night."
     38  * Set 4: Message 14 = "Please "
     39  *        Message 19 = "Thank you."
     40  *        Message 20 = "Sincerely,"
     41  *
     42  * The ICU resource bundle source file would, assuming it is named
     43  * "greet.txt", would look like this:
     44  *
     45  * greet
     46  * {
     47  *     1%4  { "Good morning." }
     48  *     1%5  { "Good afternoon." }
     49  *     1%7  { "Good evening." }
     50  *     1%8  { "Good night." }
     51  *
     52  *     4%14 { "Please " }
     53  *     4%19 { "Thank you." }
     54  *     4%20 { "Sincerely," }
     55  * }
     56  *
     57  * The catgets function is commonly used in combination with functions
     58  * like printf and strftime.  ICU components like message format can
     59  * be used instead, although they use a different format syntax.
     60  * There is an ICU package, icuio, that provides some of
     61  * the POSIX-style formatting API.
     62  */
     63 
     64 U_CDECL_BEGIN
     65 
     66 /**
     67  * An ICU message catalog descriptor, analogous to nl_catd.
     68  *
     69  * @stable ICU 2.6
     70  */
     71 typedef UResourceBundle* u_nl_catd;
     72 
     73 /**
     74  * Open and return an ICU message catalog descriptor. The descriptor
     75  * may be passed to u_catgets() to retrieve localized strings.
     76  *
     77  * @param name string containing the full path pointing to the
     78  * directory where the resources reside followed by the package name
     79  * e.g. "/usr/resource/my_app/resources/guimessages" on a Unix system.
     80  * If NULL, ICU default data files will be used.
     81  *
     82  * Unlike POSIX, environment variables are not interpolated within the
     83  * name.
     84  *
     85  * @param locale the locale for which we want to open the resource. If
     86  * NULL, the default ICU locale will be used (see uloc_getDefault). If
     87  * strlen(locale) == 0, the root locale will be used.
     88  *
     89  * @param ec input/output error code. Upon output,
     90  * U_USING_FALLBACK_WARNING indicates that a fallback locale was
     91  * used. For example, 'de_CH' was requested, but nothing was found
     92  * there, so 'de' was used. U_USING_DEFAULT_WARNING indicates that the
     93  * default locale data or root locale data was used; neither the
     94  * requested locale nor any of its fallback locales were found.
     95  *
     96  * @return a message catalog descriptor that may be passed to
     97  * u_catgets(). If the ec parameter indicates success, then the caller
     98  * is responsible for calling u_catclose() to close the message
     99  * catalog. If the ec parameter indicates failure, then NULL will be
    100  * returned.
    101  *
    102  * @stable ICU 2.6
    103  */
    104 U_STABLE u_nl_catd U_EXPORT2
    105 u_catopen(const char* name, const char* locale, UErrorCode* ec);
    106 
    107 /**
    108  * Close an ICU message catalog, given its descriptor.
    109  *
    110  * @param catd a message catalog descriptor to be closed. May be NULL,
    111  * in which case no action is taken.
    112  *
    113  * @stable ICU 2.6
    114  */
    115 U_STABLE void U_EXPORT2
    116 u_catclose(u_nl_catd catd);
    117 
    118 /**
    119  * Retrieve a localized string from an ICU message catalog.
    120  *
    121  * @param catd a message catalog descriptor returned by u_catopen.
    122  *
    123  * @param set_num the message catalog set number. Sets need not be
    124  * numbered consecutively.
    125  *
    126  * @param msg_num the message catalog message number within the
    127  * set. Messages need not be numbered consecutively.
    128  *
    129  * @param s the default string. This is returned if the string
    130  * specified by the set_num and msg_num is not found. It must be
    131  * zero-terminated.
    132  *
    133  * @param len fill-in parameter to receive the length of the result.
    134  * May be NULL, in which case it is ignored.
    135  *
    136  * @param ec input/output error code. May be U_USING_FALLBACK_WARNING
    137  * or U_USING_DEFAULT_WARNING. U_MISSING_RESOURCE_ERROR indicates that
    138  * the set_num/msg_num tuple does not specify a valid message string
    139  * in this catalog.
    140  *
    141  * @return a pointer to a zero-terminated UChar array which lives in
    142  * an internal buffer area, typically a memory mapped/DLL file. The
    143  * caller must NOT delete this pointer. If the call is unsuccessful
    144  * for any reason, then s is returned.  This includes the situation in
    145  * which ec indicates a failing error code upon entry to this
    146  * function.
    147  *
    148  * @stable ICU 2.6
    149  */
    150 U_STABLE const UChar* U_EXPORT2
    151 u_catgets(u_nl_catd catd, int32_t set_num, int32_t msg_num,
    152           const UChar* s,
    153           int32_t* len, UErrorCode* ec);
    154 
    155 U_CDECL_END
    156 
    157 #endif /*UCAT_H*/
    158 /*eof*/
    159