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// © 2016 and later: Unicode, Inc. and others.
// License & terms of use: http://www.unicode.org/copyright.html
/*
* Copyright (C) 2007-2013, International Business Machines Corporation and
* others. All Rights Reserved.
********************************************************************************
*
* File MSGFMT.H
*
* Modification History:
*
* Date Name Description
* 02/19/97 aliu Converted from java.
* 03/20/97 helena Finished first cut of implementation.
* 07/22/98 stephen Removed operator!= (defined in Format)
* 08/19/2002 srl Removing Javaisms
*******************************************************************************/
#ifndef MSGFMT_H
#define MSGFMT_H
#include "unicode/utypes.h"
#if U_SHOW_CPLUSPLUS_API
/**
* \file
* \brief C++ API: Formats messages in a language-neutral way.
*/
#if !UCONFIG_NO_FORMATTING
#include "unicode/format.h"
#include "unicode/locid.h"
#include "unicode/messagepattern.h"
#include "unicode/parseerr.h"
#include "unicode/plurfmt.h"
#include "unicode/plurrule.h"
U_CDECL_BEGIN
// Forward declaration.
struct UHashtable;
typedef struct UHashtable UHashtable; /**< @internal */
U_CDECL_END
U_NAMESPACE_BEGIN
class AppendableWrapper;
class DateFormat;
class NumberFormat;
/**
* <p>MessageFormat prepares strings for display to users,
* with optional arguments (variables/placeholders).
* The arguments can occur in any order, which is necessary for translation
* into languages with different grammars.
*
* <p>A MessageFormat is constructed from a <em>pattern</em> string
* with arguments in {curly braces} which will be replaced by formatted values.
*
* <p><code>MessageFormat</code> differs from the other <code>Format</code>
* classes in that you create a <code>MessageFormat</code> object with one
* of its constructors (not with a <code>createInstance</code> style factory
* method). Factory methods aren't necessary because <code>MessageFormat</code>
* itself doesn't implement locale-specific behavior. Any locale-specific
* behavior is defined by the pattern that you provide and the
* subformats used for inserted arguments.
*
* <p>Arguments can be named (using identifiers) or numbered (using small ASCII-digit integers).
* Some of the API methods work only with argument numbers and throw an exception
* if the pattern has named arguments (see {@link #usesNamedArguments()}).
*
* <p>An argument might not specify any format type. In this case,
* a numeric value is formatted with a default (for the locale) NumberFormat,
* and a date/time value is formatted with a default (for the locale) DateFormat.
*
* <p>An argument might specify a "simple" type for which the specified
* Format object is created, cached and used.
*
* <p>An argument might have a "complex" type with nested MessageFormat sub-patterns.
* During formatting, one of these sub-messages is selected according to the argument value
* and recursively formatted.
*
* <p>After construction, a custom Format object can be set for
* a top-level argument, overriding the default formatting and parsing behavior
* for that argument.
* However, custom formatting can be achieved more simply by writing
* a typeless argument in the pattern string
* and supplying it with a preformatted string value.
*
* <p>When formatting, MessageFormat takes a collection of argument values
* and writes an output string.
* The argument values may be passed as an array
* (when the pattern contains only numbered arguments)
* or as an array of names and and an array of arguments (which works for both named
* and numbered arguments).
*
* <p>Each argument is matched with one of the input values by array index or argument name
* and formatted according to its pattern specification
* (or using a custom Format object if one was set).
* A numbered pattern argument is matched with an argument name that contains that number
* as an ASCII-decimal-digit string (without leading zero).
*
* <h4><a name="patterns">Patterns and Their Interpretation</a></h4>
*
* <code>MessageFormat</code> uses patterns of the following form:
* <pre>
* message = messageText (argument messageText)*
* argument = noneArg | simpleArg | complexArg
* complexArg = choiceArg | pluralArg | selectArg | selectordinalArg
*
* noneArg = '{' argNameOrNumber '}'
* simpleArg = '{' argNameOrNumber ',' argType [',' argStyle] '}'
* choiceArg = '{' argNameOrNumber ',' "choice" ',' choiceStyle '}'
* pluralArg = '{' argNameOrNumber ',' "plural" ',' pluralStyle '}'
* selectArg = '{' argNameOrNumber ',' "select" ',' selectStyle '}'
* selectordinalArg = '{' argNameOrNumber ',' "selectordinal" ',' pluralStyle '}'
*
* choiceStyle: see {@link ChoiceFormat}
* pluralStyle: see {@link PluralFormat}
* selectStyle: see {@link SelectFormat}
*
* argNameOrNumber = argName | argNumber
* argName = [^[[:Pattern_Syntax:][:Pattern_White_Space:]]]+
* argNumber = '0' | ('1'..'9' ('0'..'9')*)
*
* argType = "number" | "date" | "time" | "spellout" | "ordinal" | "duration"
* argStyle = "short" | "medium" | "long" | "full" | "integer" | "currency" | "percent" | argStyleText | "::" argSkeletonText
* </pre>
*
* <ul>
* <li>messageText can contain quoted literal strings including syntax characters.
* A quoted literal string begins with an ASCII apostrophe and a syntax character
* (usually a {curly brace}) and continues until the next single apostrophe.
* A double ASCII apostrophe inside or outside of a quoted string represents
* one literal apostrophe.
* <li>Quotable syntax characters are the {curly braces} in all messageText parts,
* plus the '#' sign in a messageText immediately inside a pluralStyle,
* and the '|' symbol in a messageText immediately inside a choiceStyle.
* <li>See also {@link #UMessagePatternApostropheMode}
* <li>In argStyleText, every single ASCII apostrophe begins and ends quoted literal text,
* and unquoted {curly braces} must occur in matched pairs.
* </ul>
*
* <p>Recommendation: Use the real apostrophe (single quote) character
* \htmlonly’\endhtmlonly (U+2019) for
* human-readable text, and use the ASCII apostrophe ' (U+0027)
* only in program syntax, like quoting in MessageFormat.
* See the annotations for U+0027 Apostrophe in The Unicode Standard.
*
* <p>The <code>choice</code> argument type is deprecated.
* Use <code>plural</code> arguments for proper plural selection,
* and <code>select</code> arguments for simple selection among a fixed set of choices.
*
* <p>The <code>argType</code> and <code>argStyle</code> values are used to create
* a <code>Format</code> instance for the format element. The following
* table shows how the values map to Format instances. Combinations not
* shown in the table are illegal. Any <code>argStyleText</code> must
* be a valid pattern string for the Format subclass used.
*
* <p><table border=1>
* <tr>
* <th>argType
* <th>argStyle
* <th>resulting Format object
* <tr>
* <td colspan=2><i>(none)</i>
* <td><code>null</code>
* <tr>
* <td rowspan=6><code>number</code>
* <td><i>(none)</i>
* <td><code>NumberFormat.createInstance(getLocale(), status)</code>
* <tr>
* <td><code>integer</code>
* <td><code>NumberFormat.createInstance(getLocale(), kNumberStyle, status)</code>
* <tr>
* <td><code>currency</code>
* <td><code>NumberFormat.createCurrencyInstance(getLocale(), status)</code>
* <tr>
* <td><code>percent</code>
* <td><code>NumberFormat.createPercentInstance(getLocale(), status)</code>
* <tr>
* <td><i>argStyleText</i>
* <td><code>new DecimalFormat(argStyleText, new DecimalFormatSymbols(getLocale(), status), status)</code>
* <tr>
* <td><i>argSkeletonText</i>
* <td><code>NumberFormatter::forSkeleton(argSkeletonText, status).locale(getLocale()).toFormat(status)</code>
* <tr>
* <td rowspan=7><code>date</code>
* <td><i>(none)</i>
* <td><code>DateFormat.createDateInstance(kDefault, getLocale(), status)</code>
* <tr>
* <td><code>short</code>
* <td><code>DateFormat.createDateInstance(kShort, getLocale(), status)</code>
* <tr>
* <td><code>medium</code>
* <td><code>DateFormat.createDateInstance(kDefault, getLocale(), status)</code>
* <tr>
* <td><code>long</code>
* <td><code>DateFormat.createDateInstance(kLong, getLocale(), status)</code>
* <tr>
* <td><code>full</code>
* <td><code>DateFormat.createDateInstance(kFull, getLocale(), status)</code>
* <tr>
* <td><i>argStyleText</i>
* <td><code>new SimpleDateFormat(argStyleText, getLocale(), status)</code>
* <tr>
* <td><i>argSkeletonText</i>
* <td><code>DateFormat::createInstanceForSkeleton(argSkeletonText, getLocale(), status)</code>
* <tr>
* <td rowspan=6><code>time</code>
* <td><i>(none)</i>
* <td><code>DateFormat.createTimeInstance(kDefault, getLocale(), status)</code>
* <tr>
* <td><code>short</code>
* <td><code>DateFormat.createTimeInstance(kShort, getLocale(), status)</code>
* <tr>
* <td><code>medium</code>
* <td><code>DateFormat.createTimeInstance(kDefault, getLocale(), status)</code>
* <tr>
* <td><code>long</code>
* <td><code>DateFormat.createTimeInstance(kLong, getLocale(), status)</code>
* <tr>
* <td><code>full</code>
* <td><code>DateFormat.createTimeInstance(kFull, getLocale(), status)</code>
* <tr>
* <td><i>argStyleText</i>
* <td><code>new SimpleDateFormat(argStyleText, getLocale(), status)</code>
* <tr>
* <td><code>spellout</code>
* <td><i>argStyleText (optional)</i>
* <td><code>new RuleBasedNumberFormat(URBNF_SPELLOUT, getLocale(), status)
* <br/> .setDefaultRuleset(argStyleText, status);</code>
* <tr>
* <td><code>ordinal</code>
* <td><i>argStyleText (optional)</i>
* <td><code>new RuleBasedNumberFormat(URBNF_ORDINAL, getLocale(), status)
* <br/> .setDefaultRuleset(argStyleText, status);</code>
* <tr>
* <td><code>duration</code>
* <td><i>argStyleText (optional)</i>
* <td><code>new RuleBasedNumberFormat(URBNF_DURATION, getLocale(), status)
* <br/> .setDefaultRuleset(argStyleText, status);</code>
* </table>
* <p>
*
* <h4>Argument formatting</h4>
*
* <p>Arguments are formatted according to their type, using the default
* ICU formatters for those types, unless otherwise specified.</p>
*
* <p>There are also several ways to control the formatting.</p>
*
* <p>We recommend you use default styles, predefined style values, skeletons,
* or preformatted values, but not pattern strings or custom format objects.</p>
*
* <p>For more details, see the
* <a href="https://unicode-org.github.io/icu/userguide/format_parse/messages">ICU User Guide</a>.</p>
*
* <h4>Usage Information</h4>
*
* <p>Here are some examples of usage:
* Example 1:
*
* <pre>
* \code
* UErrorCode success = U_ZERO_ERROR;
* GregorianCalendar cal(success);
* Formattable arguments[] = {
* 7L,
* Formattable( (Date) cal.getTime(success), Formattable::kIsDate),
* "a disturbance in the Force"
* };
*
* UnicodeString result;
* MessageFormat::format(
* "At {1,time,::jmm} on {1,date,::dMMMM}, there was {2} on planet {0,number}.",
* arguments, 3, result, success );
*
* cout << "result: " << result << endl;
* //<output>: At 4:34 PM on March 23, there was a disturbance
* // in the Force on planet 7.
* \endcode
* </pre>
*
* Typically, the message format will come from resources, and the
* arguments will be dynamically set at runtime.
*
* <p>Example 2:
*
* <pre>
* \code
* success = U_ZERO_ERROR;
* Formattable testArgs[] = {3L, "MyDisk"};
*
* MessageFormat form(
* "The disk \"{1}\" contains {0} file(s).", success );
*
* UnicodeString string;
* FieldPosition fpos = 0;
* cout << "format: " << form.format(testArgs, 2, string, fpos, success ) << endl;
*
* // output, with different testArgs:
* // output: The disk "MyDisk" contains 0 file(s).
* // output: The disk "MyDisk" contains 1 file(s).
* // output: The disk "MyDisk" contains 1,273 file(s).
* \endcode
* </pre>
*
*
* <p>For messages that include plural forms, you can use a plural argument:
* <pre>
* \code
* success = U_ZERO_ERROR;
* MessageFormat msgFmt(
* "{num_files, plural, "
* "=0{There are no files on disk \"{disk_name}\".}"
* "=1{There is one file on disk \"{disk_name}\".}"
* "other{There are # files on disk \"{disk_name}\".}}",
* Locale("en"),
* success);
* FieldPosition fpos = 0;
* Formattable testArgs[] = {0L, "MyDisk"};
* UnicodeString testArgsNames[] = {"num_files", "disk_name"};
* UnicodeString result;
* cout << msgFmt.format(testArgs, testArgsNames, 2, result, fpos, 0, success);
* testArgs[0] = 3L;
* cout << msgFmt.format(testArgs, testArgsNames, 2, result, fpos, 0, success);
* \endcode
* <em>output</em>:
* There are no files on disk "MyDisk".
* There are 3 files on "MyDisk".
* </pre>
* See {@link PluralFormat} and {@link PluralRules} for details.
*
* <h4><a name="synchronization">Synchronization</a></h4>
*
* <p>MessageFormats are not synchronized.
* It is recommended to create separate format instances for each thread.
* If multiple threads access a format concurrently, it must be synchronized
* externally.
*
* @stable ICU 2.0
*/
class U_I18N_API MessageFormat : public Format {
public:
#ifndef U_HIDE_OBSOLETE_API
/**
* Enum type for kMaxFormat.
* @obsolete ICU 3.0. The 10-argument limit was removed as of ICU 2.6,
* rendering this enum type obsolete.
*/
enum EFormatNumber {
/**
* The maximum number of arguments.
* @obsolete ICU 3.0. The 10-argument limit was removed as of ICU 2.6,
* rendering this constant obsolete.
*/
kMaxFormat = 10
};
#endif /* U_HIDE_OBSOLETE_API */
/**
* Constructs a new MessageFormat using the given pattern and the
* default locale.
*
* @param pattern Pattern used to construct object.
* @param status Input/output error code. If the
* pattern cannot be parsed, set to failure code.
* @stable ICU 2.0
*/
MessageFormat(const UnicodeString& pattern,
UErrorCode &status);
/**
* Constructs a new MessageFormat using the given pattern and locale.
* @param pattern Pattern used to construct object.
* @param newLocale The locale to use for formatting dates and numbers.
* @param status Input/output error code. If the
* pattern cannot be parsed, set to failure code.
* @stable ICU 2.0
*/
MessageFormat(const UnicodeString& pattern,
const Locale& newLocale,
UErrorCode& status);
/**
* Constructs a new MessageFormat using the given pattern and locale.
* @param pattern Pattern used to construct object.
* @param newLocale The locale to use for formatting dates and numbers.
* @param parseError Struct to receive information on the position
* of an error within the pattern.
* @param status Input/output error code. If the
* pattern cannot be parsed, set to failure code.
* @stable ICU 2.0
*/
MessageFormat(const UnicodeString& pattern,
const Locale& newLocale,
UParseError& parseError,
UErrorCode& status);
/**
* Constructs a new MessageFormat from an existing one.
* @stable ICU 2.0
*/
MessageFormat(const MessageFormat&);
/**
* Assignment operator.
* @stable ICU 2.0
*/
const MessageFormat& operator=(const MessageFormat&);
/**
* Destructor.
* @stable ICU 2.0
*/
virtual ~MessageFormat();
/**
* Clones this Format object polymorphically. The caller owns the
* result and should delete it when done.
* @stable ICU 2.0
*/
virtual MessageFormat* clone() const override;
/**
* Returns true if the given Format objects are semantically equal.
* Objects of different subclasses are considered unequal.
* @param other the object to be compared with.
* @return true if the given Format objects are semantically equal.
* @stable ICU 2.0
*/
virtual bool operator==(const Format& other) const override;
/**
* Sets the locale to be used for creating argument Format objects.
* @param theLocale the new locale value to be set.
* @stable ICU 2.0
*/
virtual void setLocale(const Locale& theLocale);
/**
* Gets the locale used for creating argument Format objects.
* format information.
* @return the locale of the object.
* @stable ICU 2.0
*/
virtual const Locale& getLocale() const;
/**
* Applies the given pattern string to this message format.
*
* @param pattern The pattern to be applied.
* @param status Input/output error code. If the
* pattern cannot be parsed, set to failure code.
* @stable ICU 2.0
*/
virtual void applyPattern(const UnicodeString& pattern,
UErrorCode& status);
/**
* Applies the given pattern string to this message format.
*
* @param pattern The pattern to be applied.
* @param parseError Struct to receive information on the position
* of an error within the pattern.
* @param status Input/output error code. If the
* pattern cannot be parsed, set to failure code.
* @stable ICU 2.0
*/
virtual void applyPattern(const UnicodeString& pattern,
UParseError& parseError,
UErrorCode& status);
/**
* Sets the UMessagePatternApostropheMode and the pattern used by this message format.
* Parses the pattern and caches Format objects for simple argument types.
* Patterns and their interpretation are specified in the
* <a href="#patterns">class description</a>.
* <p>
* This method is best used only once on a given object to avoid confusion about the mode,
* and after constructing the object with an empty pattern string to minimize overhead.
*
* @param pattern The pattern to be applied.
* @param aposMode The new apostrophe mode.
* @param parseError Struct to receive information on the position
* of an error within the pattern.
* Can be nullptr.
* @param status Input/output error code. If the
* pattern cannot be parsed, set to failure code.
* @stable ICU 4.8
*/
virtual void applyPattern(const UnicodeString& pattern,
UMessagePatternApostropheMode aposMode,
UParseError* parseError,
UErrorCode& status);
/**
* @return this instance's UMessagePatternApostropheMode.
* @stable ICU 4.8
*/
UMessagePatternApostropheMode getApostropheMode() const {
return msgPattern.getApostropheMode();
}
/**
* Returns a pattern that can be used to recreate this object.
*
* @param appendTo Output parameter to receive the pattern.
* Result is appended to existing contents.
* @return Reference to 'appendTo' parameter.
* @stable ICU 2.0
*/
virtual UnicodeString& toPattern(UnicodeString& appendTo) const;
/**
* Sets subformats.
* See the class description about format numbering.
* The caller should not delete the Format objects after this call.
* <EM>The array formatsToAdopt is not itself adopted.</EM> Its
* ownership is retained by the caller. If the call fails because
* memory cannot be allocated, then the formats will be deleted
* by this method, and this object will remain unchanged.
*
* <p>If this format uses named arguments, the new formats are discarded
* and this format remains unchanged.
*
* @stable ICU 2.0
* @param formatsToAdopt the format to be adopted.
* @param count the size of the array.
*/
virtual void adoptFormats(Format** formatsToAdopt, int32_t count);
/**
* Sets subformats.
* See the class description about format numbering.
* Each item in the array is cloned into the internal array.
* If the call fails because memory cannot be allocated, then this
* object will remain unchanged.
*
* <p>If this format uses named arguments, the new formats are discarded
* and this format remains unchanged.
*
* @stable ICU 2.0
* @param newFormats the new format to be set.
* @param cnt the size of the array.
*/
virtual void setFormats(const Format** newFormats, int32_t cnt);
/**
* Sets one subformat.
* See the class description about format numbering.
* The caller should not delete the Format object after this call.
* If the number is over the number of formats already set,
* the item will be deleted and ignored.
*
* <p>If this format uses named arguments, the new format is discarded
* and this format remains unchanged.
*
* @stable ICU 2.0
* @param formatNumber index of the subformat.
* @param formatToAdopt the format to be adopted.
*/
virtual void adoptFormat(int32_t formatNumber, Format* formatToAdopt);
/**
* Sets one subformat.
* See the class description about format numbering.
* If the number is over the number of formats already set,
* the item will be ignored.
* @param formatNumber index of the subformat.
* @param format the format to be set.
* @stable ICU 2.0
*/
virtual void setFormat(int32_t formatNumber, const Format& format);
/**
* Gets format names. This function returns formatNames in StringEnumerations
* which can be used with getFormat() and setFormat() to export formattable
* array from current MessageFormat to another. It is the caller's responsibility
* to delete the returned formatNames.
* @param status output param set to success/failure code.
* @stable ICU 4.0
*/
virtual StringEnumeration* getFormatNames(UErrorCode& status);
/**
* Gets subformat pointer for given format name.
* This function supports both named and numbered
* arguments. If numbered, the formatName is the
* corresponding UnicodeStrings (e.g. "0", "1", "2"...).
* The returned Format object should not be deleted by the caller,
* nor should the pointer of other object . The pointer and its
* contents remain valid only until the next call to any method
* of this class is made with this object.
* @param formatName the name or number specifying a format
* @param status output param set to success/failure code.
* @stable ICU 4.0
*/
virtual Format* getFormat(const UnicodeString& formatName, UErrorCode& status);
/**
* Sets one subformat for given format name.
* See the class description about format name.
* This function supports both named and numbered
* arguments-- if numbered, the formatName is the
* corresponding UnicodeStrings (e.g. "0", "1", "2"...).
* If there is no matched formatName or wrong type,
* the item will be ignored.
* @param formatName Name of the subformat.
* @param format the format to be set.
* @param status output param set to success/failure code.
* @stable ICU 4.0
*/
virtual void setFormat(const UnicodeString& formatName, const Format& format, UErrorCode& status);
/**
* Sets one subformat for given format name.
* See the class description about format name.
* This function supports both named and numbered
* arguments-- if numbered, the formatName is the
* corresponding UnicodeStrings (e.g. "0", "1", "2"...).
* If there is no matched formatName or wrong type,
* the item will be ignored.
* The caller should not delete the Format object after this call.
* @param formatName Name of the subformat.
* @param formatToAdopt Format to be adopted.
* @param status output param set to success/failure code.
* @stable ICU 4.0
*/
virtual void adoptFormat(const UnicodeString& formatName, Format* formatToAdopt, UErrorCode& status);
/**
* Gets an array of subformats of this object. The returned array
* should not be deleted by the caller, nor should the pointers
* within the array. The array and its contents remain valid only
* until the next call to this format. See the class description
* about format numbering.
*
* @param count output parameter to receive the size of the array
* @return an array of count Format* objects, or nullptr if out of
* memory. Any or all of the array elements may be nullptr.
* @stable ICU 2.0
*/
virtual const Format** getFormats(int32_t& count) const;
using Format::format;
/**
* Formats the given array of arguments into a user-readable string.
* Does not take ownership of the Formattable* array or its contents.
*
* <p>If this format uses named arguments, appendTo is unchanged and
* status is set to U_ILLEGAL_ARGUMENT_ERROR.
*
* @param source An array of objects to be formatted.
* @param count The number of elements of 'source'.
* @param appendTo Output parameter to receive result.
* Result is appended to existing contents.
* @param ignore Not used; inherited from base class API.
* @param status Input/output error code. If the
* pattern cannot be parsed, set to failure code.
* @return Reference to 'appendTo' parameter.
* @stable ICU 2.0
*/
UnicodeString& format(const Formattable* source,
int32_t count,
UnicodeString& appendTo,
FieldPosition& ignore,
UErrorCode& status) const;
/**
* Formats the given array of arguments into a user-readable string
* using the given pattern.
*
* <p>If this format uses named arguments, appendTo is unchanged and
* status is set to U_ILLEGAL_ARGUMENT_ERROR.
*
* @param pattern The pattern.
* @param arguments An array of objects to be formatted.
* @param count The number of elements of 'source'.
* @param appendTo Output parameter to receive result.
* Result is appended to existing contents.
* @param status Input/output error code. If the
* pattern cannot be parsed, set to failure code.
* @return Reference to 'appendTo' parameter.
* @stable ICU 2.0
*/
static UnicodeString& format(const UnicodeString& pattern,
const Formattable* arguments,
int32_t count,
UnicodeString& appendTo,
UErrorCode& status);
/**
* Formats the given array of arguments into a user-readable
* string. The array must be stored within a single Formattable
* object of type kArray. If the Formattable object type is not of
* type kArray, then returns a failing UErrorCode.
*
* <p>If this format uses named arguments, appendTo is unchanged and
* status is set to U_ILLEGAL_ARGUMENT_ERROR.
*
* @param obj A Formattable of type kArray containing
* arguments to be formatted.
* @param appendTo Output parameter to receive result.
* Result is appended to existing contents.
* @param pos On input: an alignment field, if desired.
* On output: the offsets of the alignment field.
* @param status Input/output error code. If the
* pattern cannot be parsed, set to failure code.
* @return Reference to 'appendTo' parameter.
* @stable ICU 2.0
*/
virtual UnicodeString& format(const Formattable& obj,
UnicodeString& appendTo,
FieldPosition& pos,
UErrorCode& status) const override;
/**
* Formats the given array of arguments into a user-defined argument name
* array. This function supports both named and numbered
* arguments-- if numbered, the formatName is the
* corresponding UnicodeStrings (e.g. "0", "1", "2"...).
*
* @param argumentNames argument name array
* @param arguments An array of objects to be formatted.
* @param count The number of elements of 'argumentNames' and
* arguments. The number of argumentNames and arguments
* must be the same.
* @param appendTo Output parameter to receive result.
* Result is appended to existing contents.
* @param status Input/output error code. If the
* pattern cannot be parsed, set to failure code.
* @return Reference to 'appendTo' parameter.
* @stable ICU 4.0
*/
UnicodeString& format(const UnicodeString* argumentNames,
const Formattable* arguments,
int32_t count,
UnicodeString& appendTo,
UErrorCode& status) const;
/**
* Parses the given string into an array of output arguments.
*
* @param source String to be parsed.
* @param pos On input, starting position for parse. On output,
* final position after parse. Unchanged if parse
* fails.
* @param count Output parameter to receive the number of arguments
* parsed.
* @return an array of parsed arguments. The caller owns both
* the array and its contents.
* @stable ICU 2.0
*/
virtual Formattable* parse(const UnicodeString& source,
ParsePosition& pos,
int32_t& count) const;
/**
* Parses the given string into an array of output arguments.
*
* <p>If this format uses named arguments, status is set to
* U_ARGUMENT_TYPE_MISMATCH.
*
* @param source String to be parsed.
* @param count Output param to receive size of returned array.
* @param status Input/output error code. If the
* pattern cannot be parsed, set to failure code.
* @return an array of parsed arguments. The caller owns both
* the array and its contents. Returns nullptr if status is not U_ZERO_ERROR.
*
* @stable ICU 2.0
*/
virtual Formattable* parse(const UnicodeString& source,
int32_t& count,
UErrorCode& status) const;
/**
* Parses the given string into an array of output arguments
* stored within a single Formattable of type kArray.
*
* @param source The string to be parsed into an object.
* @param result Formattable to be set to the parse result.
* If parse fails, return contents are undefined.
* @param pos On input, starting position for parse. On output,
* final position after parse. Unchanged if parse
* fails.
* @stable ICU 2.0
*/
virtual void parseObject(const UnicodeString& source,
Formattable& result,
ParsePosition& pos) const override;
/**
* Convert an 'apostrophe-friendly' pattern into a standard
* pattern. Standard patterns treat all apostrophes as
* quotes, which is problematic in some languages, e.g.
* French, where apostrophe is commonly used. This utility
* assumes that only an unpaired apostrophe immediately before
* a brace is a true quote. Other unpaired apostrophes are paired,
* and the resulting standard pattern string is returned.
*
* <p><b>Note</b> it is not guaranteed that the returned pattern
* is indeed a valid pattern. The only effect is to convert
* between patterns having different quoting semantics.
*
* @param pattern the 'apostrophe-friendly' patttern to convert
* @param status Input/output error code. If the pattern
* cannot be parsed, the failure code is set.
* @return the standard equivalent of the original pattern
* @stable ICU 3.4
*/
static UnicodeString autoQuoteApostrophe(const UnicodeString& pattern,
UErrorCode& status);
/**
* Returns true if this MessageFormat uses named arguments,
* and false otherwise. See class description.
*
* @return true if named arguments are used.
* @stable ICU 4.0
*/
UBool usesNamedArguments() const;
#ifndef U_HIDE_INTERNAL_API
/**
* This API is for ICU internal use only.
* Please do not use it.
*
* Returns argument types count in the parsed pattern.
* Used to distinguish pattern "{0} d" and "d".
*
* @return The number of formattable types in the pattern
* @internal
*/
int32_t getArgTypeCount() const;
#endif /* U_HIDE_INTERNAL_API */
/**
* Returns a unique class ID POLYMORPHICALLY. Pure virtual override.
* This method is to implement a simple version of RTTI, since not all
* C++ compilers support genuine RTTI. Polymorphic operator==() and
* clone() methods call this method.
*
* @return The class ID for this object. All objects of a
* given class have the same class ID. Objects of
* other classes have different class IDs.
* @stable ICU 2.0
*/
virtual UClassID getDynamicClassID() const override;
/**
* Return the class ID for this class. This is useful only for
* comparing to a return value from getDynamicClassID(). For example:
* <pre>
* . Base* polymorphic_pointer = createPolymorphicObject();
* . if (polymorphic_pointer->getDynamicClassID() ==
* . Derived::getStaticClassID()) ...
* </pre>
* @return The class ID for all objects of this class.
* @stable ICU 2.0
*/
static UClassID U_EXPORT2 getStaticClassID();
#ifndef U_HIDE_INTERNAL_API
/**
* Compares two Format objects. This is used for constructing the hash
* tables.
*
* @param left pointer to a Format object. Must not be nullptr.
* @param right pointer to a Format object. Must not be nullptr.
*
* @return whether the two objects are the same
* @internal
*/
static UBool equalFormats(const void* left, const void* right);
#endif /* U_HIDE_INTERNAL_API */
private:
Locale fLocale;
MessagePattern msgPattern;
Format** formatAliases; // see getFormats
int32_t formatAliasesCapacity;
MessageFormat() = delete; // default constructor not implemented
/**
* This provider helps defer instantiation of a PluralRules object
* until we actually need to select a keyword.
* For example, if the number matches an explicit-value selector like "=1"
* we do not need any PluralRules.
*/
class U_I18N_API PluralSelectorProvider : public PluralFormat::PluralSelector {
public:
PluralSelectorProvider(const MessageFormat &mf, UPluralType type);
virtual ~PluralSelectorProvider();
virtual UnicodeString select(void *ctx, double number, UErrorCode& ec) const override;
void reset();
private:
const MessageFormat &msgFormat;
PluralRules* rules;
UPluralType type;
};
/**
* A MessageFormat formats an array of arguments. Each argument
* has an expected type, based on the pattern. For example, if
* the pattern contains the subformat "{3,number,integer}", then
* we expect argument 3 to have type Formattable::kLong. This
* array needs to grow dynamically if the MessageFormat is
* modified.
*/
Formattable::Type* argTypes;
int32_t argTypeCount;
int32_t argTypeCapacity;
/**
* true if there are different argTypes for the same argument.
* This only matters when the MessageFormat is used in the plain C (umsg_xxx) API
* where the pattern argTypes determine how the va_arg list is read.
*/
UBool hasArgTypeConflicts;
// Variable-size array management
UBool allocateArgTypes(int32_t capacity, UErrorCode& status);
/**
* Default Format objects used when no format is specified and a
* numeric or date argument is formatted. These are volatile
* cache objects maintained only for performance. They do not
* participate in operator=(), copy constructor(), nor
* operator==().
*/
NumberFormat* defaultNumberFormat;
DateFormat* defaultDateFormat;
UHashtable* cachedFormatters;
UHashtable* customFormatArgStarts;
PluralSelectorProvider pluralProvider;
PluralSelectorProvider ordinalProvider;
/**
* Method to retrieve default formats (or nullptr on failure).
* These are semantically const, but may modify *this.
*/
const NumberFormat* getDefaultNumberFormat(UErrorCode&) const;
const DateFormat* getDefaultDateFormat(UErrorCode&) const;
/**
* Finds the word s, in the keyword list and returns the located index.
* @param s the keyword to be searched for.
* @param list the list of keywords to be searched with.
* @return the index of the list which matches the keyword s.
*/
static int32_t findKeyword( const UnicodeString& s,
const char16_t * const *list);
/**
* Thin wrapper around the format(... AppendableWrapper ...) variant.
* Wraps the destination UnicodeString into an AppendableWrapper and
* supplies default values for some other parameters.
*/
UnicodeString& format(const Formattable* arguments,
const UnicodeString *argumentNames,
int32_t cnt,
UnicodeString& appendTo,
FieldPosition* pos,
UErrorCode& status) const;
/**
* Formats the arguments and writes the result into the
* AppendableWrapper, updates the field position.
*
* @param msgStart Index to msgPattern part to start formatting from.
* @param plNumber nullptr except when formatting a plural argument sub-message
* where a '#' is replaced by the format string for this number.
* @param arguments The formattable objects array. (Must not be nullptr.)
* @param argumentNames nullptr if numbered values are used. Otherwise the same
* length as "arguments", and each entry is the name of the
* corresponding argument in "arguments".
* @param cnt The length of arguments (and of argumentNames if that is not nullptr).
* @param appendTo Output parameter to receive the result.
* The result string is appended to existing contents.
* @param pos Field position status.
* @param success The error code status.
*/
void format(int32_t msgStart,
const void *plNumber,
const Formattable* arguments,
const UnicodeString *argumentNames,
int32_t cnt,
AppendableWrapper& appendTo,
FieldPosition* pos,
UErrorCode& success) const;
UnicodeString getArgName(int32_t partIndex);
void setArgStartFormat(int32_t argStart, Format* formatter, UErrorCode& status);
void setCustomArgStartFormat(int32_t argStart, Format* formatter, UErrorCode& status);
int32_t nextTopLevelArgStart(int32_t partIndex) const;
UBool argNameMatches(int32_t partIndex, const UnicodeString& argName, int32_t argNumber);
void cacheExplicitFormats(UErrorCode& status);
Format* createAppropriateFormat(UnicodeString& type,
UnicodeString& style,
Formattable::Type& formattableType,
UParseError& parseError,
UErrorCode& ec);
const Formattable* getArgFromListByName(const Formattable* arguments,
const UnicodeString *argumentNames,
int32_t cnt, UnicodeString& name) const;
Formattable* parse(int32_t msgStart,
const UnicodeString& source,
ParsePosition& pos,
int32_t& count,
UErrorCode& ec) const;
FieldPosition* updateMetaData(AppendableWrapper& dest, int32_t prevLength,
FieldPosition* fp, const Formattable* argId) const;
/**
* Finds the "other" sub-message.
* @param partIndex the index of the first PluralFormat argument style part.
* @return the "other" sub-message start part index.
*/
int32_t findOtherSubMessage(int32_t partIndex) const;
/**
* Returns the ARG_START index of the first occurrence of the plural number in a sub-message.
* Returns -1 if it is a REPLACE_NUMBER.
* Returns 0 if there is neither.
*/
int32_t findFirstPluralNumberArg(int32_t msgStart, const UnicodeString &argName) const;
Format* getCachedFormatter(int32_t argumentNumber) const;
UnicodeString getLiteralStringUntilNextArgument(int32_t from) const;
void copyObjects(const MessageFormat& that, UErrorCode& ec);
void formatComplexSubMessage(int32_t msgStart,
const void *plNumber,
const Formattable* arguments,
const UnicodeString *argumentNames,
int32_t cnt,
AppendableWrapper& appendTo,
UErrorCode& success) const;
/**
* Convenience method that ought to be in NumberFormat
*/
NumberFormat* createIntegerFormat(const Locale& locale, UErrorCode& status) const;
/**
* Returns array of argument types in the parsed pattern
* for use in C API. Only for the use of umsg_vformat(). Not
* for public consumption.
* @param listCount Output parameter to receive the size of array
* @return The array of formattable types in the pattern
*/
const Formattable::Type* getArgTypeList(int32_t& listCount) const {
listCount = argTypeCount;
return argTypes;
}
/**
* Resets the internal MessagePattern, and other associated caches.
*/
void resetPattern();
/**
* A DummyFormatter that we use solely to store a nullptr value. UHash does
* not support storing nullptr values.
*/
class U_I18N_API DummyFormat : public Format {
public:
virtual bool operator==(const Format&) const override;
virtual DummyFormat* clone() const override;
virtual UnicodeString& format(const Formattable& obj,
UnicodeString& appendTo,
UErrorCode& status) const;
virtual UnicodeString& format(const Formattable&,
UnicodeString& appendTo,
FieldPosition&,
UErrorCode& status) const override;
virtual UnicodeString& format(const Formattable& obj,
UnicodeString& appendTo,
FieldPositionIterator* posIter,
UErrorCode& status) const override;
virtual void parseObject(const UnicodeString&,
Formattable&,
ParsePosition&) const override;
};
friend class MessageFormatAdapter; // getFormatTypeList() access
};
U_NAMESPACE_END
#endif /* #if !UCONFIG_NO_FORMATTING */
#endif /* U_SHOW_CPLUSPLUS_API */
#endif // _MSGFMT
//eof
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