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      1 // Copyright (C) 2016 and later: Unicode, Inc. and others.
      2 // License & terms of use: http://www.unicode.org/copyright.html
      3 /*
      4 **********************************************************************
      5 * Copyright (c) 2003-2004, International Business Machines
      6 * Corporation and others.  All Rights Reserved.
      7 **********************************************************************
      8 * Author: Alan Liu
      9 * Created: March 19 2003
     10 * Since: ICU 2.6
     11 **********************************************************************
     12 */
     13 #ifndef UCAT_H
     14 #define UCAT_H
     15 
     16 #include "unicode/utypes.h"
     17 #include "unicode/ures.h"
     18 
     19 /**
     20  * \file
     21  * \brief C API: Message Catalog Wrappers
     22  *
     23  * This C API provides look-alike functions that deliberately resemble
     24  * the POSIX catopen, catclose, and catgets functions.  The underlying
     25  * implementation is in terms of ICU resource bundles, rather than
     26  * POSIX message catalogs.
     27  *
     28  * The ICU resource bundles obey standard ICU inheritance policies.
     29  * To facilitate this, sets and messages are flattened into one tier.
     30  * This is done by creating resource bundle keys of the form
     31  * <set_num>%<msg_num> where set_num is the set number and msg_num is
     32  * the message number, formatted as decimal strings.
     33  *
     34  * Example:  Consider a message catalog containing two sets:
     35  *
     36  * Set 1: Message 4  = "Good morning."
     37  *        Message 5  = "Good afternoon."
     38  *        Message 7  = "Good evening."
     39  *        Message 8  = "Good night."
     40  * Set 4: Message 14 = "Please "
     41  *        Message 19 = "Thank you."
     42  *        Message 20 = "Sincerely,"
     43  *
     44  * The ICU resource bundle source file would, assuming it is named
     45  * "greet.txt", would look like this:
     46  *
     47  * greet
     48  * {
     49  *     1%4  { "Good morning." }
     50  *     1%5  { "Good afternoon." }
     51  *     1%7  { "Good evening." }
     52  *     1%8  { "Good night." }
     53  *
     54  *     4%14 { "Please " }
     55  *     4%19 { "Thank you." }
     56  *     4%20 { "Sincerely," }
     57  * }
     58  *
     59  * The catgets function is commonly used in combination with functions
     60  * like printf and strftime.  ICU components like message format can
     61  * be used instead, although they use a different format syntax.
     62  * There is an ICU package, icuio, that provides some of
     63  * the POSIX-style formatting API.
     64  */
     65 
     66 U_CDECL_BEGIN
     67 
     68 /**
     69  * An ICU message catalog descriptor, analogous to nl_catd.
     70  *
     71  * @stable ICU 2.6
     72  */
     73 typedef UResourceBundle* u_nl_catd;
     74 
     75 /**
     76  * Open and return an ICU message catalog descriptor. The descriptor
     77  * may be passed to u_catgets() to retrieve localized strings.
     78  *
     79  * @param name string containing the full path pointing to the
     80  * directory where the resources reside followed by the package name
     81  * e.g. "/usr/resource/my_app/resources/guimessages" on a Unix system.
     82  * If NULL, ICU default data files will be used.
     83  *
     84  * Unlike POSIX, environment variables are not interpolated within the
     85  * name.
     86  *
     87  * @param locale the locale for which we want to open the resource. If
     88  * NULL, the default ICU locale will be used (see uloc_getDefault). If
     89  * strlen(locale) == 0, the root locale will be used.
     90  *
     91  * @param ec input/output error code. Upon output,
     92  * U_USING_FALLBACK_WARNING indicates that a fallback locale was
     93  * used. For example, 'de_CH' was requested, but nothing was found
     94  * there, so 'de' was used. U_USING_DEFAULT_WARNING indicates that the
     95  * default locale data or root locale data was used; neither the
     96  * requested locale nor any of its fallback locales were found.
     97  *
     98  * @return a message catalog descriptor that may be passed to
     99  * u_catgets(). If the ec parameter indicates success, then the caller
    100  * is responsible for calling u_catclose() to close the message
    101  * catalog. If the ec parameter indicates failure, then NULL will be
    102  * returned.
    103  *
    104  * @stable ICU 2.6
    105  */
    106 U_STABLE u_nl_catd U_EXPORT2
    107 u_catopen(const char* name, const char* locale, UErrorCode* ec);
    108 
    109 /**
    110  * Close an ICU message catalog, given its descriptor.
    111  *
    112  * @param catd a message catalog descriptor to be closed. May be NULL,
    113  * in which case no action is taken.
    114  *
    115  * @stable ICU 2.6
    116  */
    117 U_STABLE void U_EXPORT2
    118 u_catclose(u_nl_catd catd);
    119 
    120 /**
    121  * Retrieve a localized string from an ICU message catalog.
    122  *
    123  * @param catd a message catalog descriptor returned by u_catopen.
    124  *
    125  * @param set_num the message catalog set number. Sets need not be
    126  * numbered consecutively.
    127  *
    128  * @param msg_num the message catalog message number within the
    129  * set. Messages need not be numbered consecutively.
    130  *
    131  * @param s the default string. This is returned if the string
    132  * specified by the set_num and msg_num is not found. It must be
    133  * zero-terminated.
    134  *
    135  * @param len fill-in parameter to receive the length of the result.
    136  * May be NULL, in which case it is ignored.
    137  *
    138  * @param ec input/output error code. May be U_USING_FALLBACK_WARNING
    139  * or U_USING_DEFAULT_WARNING. U_MISSING_RESOURCE_ERROR indicates that
    140  * the set_num/msg_num tuple does not specify a valid message string
    141  * in this catalog.
    142  *
    143  * @return a pointer to a zero-terminated UChar array which lives in
    144  * an internal buffer area, typically a memory mapped/DLL file. The
    145  * caller must NOT delete this pointer. If the call is unsuccessful
    146  * for any reason, then s is returned.  This includes the situation in
    147  * which ec indicates a failing error code upon entry to this
    148  * function.
    149  *
    150  * @stable ICU 2.6
    151  */
    152 U_STABLE const UChar* U_EXPORT2
    153 u_catgets(u_nl_catd catd, int32_t set_num, int32_t msg_num,
    154           const UChar* s,
    155           int32_t* len, UErrorCode* ec);
    156 
    157 U_CDECL_END
    158 
    159 #endif /*UCAT_H*/
    160 /*eof*/
    161