icuSources/common/unicode/ucat.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) 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  * &lt;set_num&gt;%&lt;msg_num&gt; 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*/