/* * Copyright (C) {1997-2004}, 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 !UCONFIG_NO_FORMATTING #include "unicode/format.h" #include "unicode/locid.h" #include "unicode/parseerr.h" U_NAMESPACE_BEGIN class NumberFormat; class DateFormat; /** * A MessageFormat produces concatenated messages in a * language-neutral way. It should be used for all string * concatenations that are visible to end users. * <P> * A MessageFormat contains an array of <EM>subformats</EM> arranged * within a <EM>template string</EM>. Together, the subformats and * template string determine how the MessageFormat will operate during * formatting and parsing. * <P> * Typically, both the subformats and the template string are * specified at once in a <EM>pattern</EM>. By using different * patterns for different locales, messages may be localized. * <P> * During formatting, the MessageFormat takes an array of arguments * and produces a user-readable string. Each argument is a * Formattable object; they may be passed in in an array, or as a * single Formattable object which itself contains an array. Each * argument is matched up with its corresponding subformat, which then * formats it into a string. The resultant strings are then assembled * within the string template of the MessageFormat to produce the * final output string. * <P> * During parsing, an input string is matched against the string * template of the MessageFormat to produce an array of Formattable * objects. Plain text of the template string is matched directly * against intput text. At each position in the template string where * a subformat is located, the subformat is called to parse the * corresponding segment of input text to produce an output argument. * In this way, an array of arguments is created which together * constitute the parse result. * <P> * Parsing may fail or produce unexpected results in a number of * circumstances. * <UL> * <LI>If one of the arguments does not occur in the pattern, it * will be returned as a default Formattable. * <LI>If the format of an argument is loses information, such as with * a choice format where a large number formats to "many", then the * parse may not correspond to the originally formatted argument. * <LI>MessageFormat does not handle ChoiceFormat recursion during * parsing; such parses will fail. * <LI>Parsing will not always find a match (or the correct match) if * some part of the parse is ambiguous. For example, if the pattern * "{1},{2}" is used with the string arguments {"a,b", "c"}, it will * format as "a,b,c". When the result is parsed, it will return {"a", * "b,c"}. * <LI>If a single argument is formatted more than once in the string, * then the rightmost subformat in the pattern string will produce the * parse result; prior subformats with the same argument index will * have no effect. * </UL> * Here are some examples of usage: * <P> * 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} on {1,date}, there was {2} on planet {0,number}.", * arguments, 3, result, success ); * * cout << "result: " << result << endl; * //<output>: At 4:34:20 PM on 23-Mar-98, 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> * * The pattern is of the following form. Legend: * <pre> * \code * {optional item} * (group that may be repeated)* * \endcode * </pre> * Do not confuse optional items with items inside quotes braces, such * as this: "{". Quoted braces are literals. * <pre> * \code * messageFormatPattern := string ( "{" messageFormatElement "}" string )* * * messageFormatElement := argumentIndex { "," elementFormat } * * elementFormat := "time" { "," datetimeStyle } * | "date" { "," datetimeStyle } * | "number" { "," numberStyle } * | "choice" "," choiceStyle * * datetimeStyle := "short" * | "medium" * | "long" * | "full" * | dateFormatPattern * * numberStyle := "currency" * | "percent" * | "integer" * | numberFormatPattern * * choiceStyle := choiceFormatPattern * \endcode * </pre> * If there is no elementFormat, then the argument must be a string, * which is substituted. If there is no dateTimeStyle or numberStyle, * then the default format is used (e.g. NumberFormat::createInstance(), * DateFormat::createTimeInstance(DateFormat::kDefault, ...) or DateFormat::createDateInstance(DateFormat::kDefault, ...). For * a ChoiceFormat, the pattern must always be specified, since there * is no default. * <P> * In strings, single quotes can be used to quote syntax characters. * A literal single quote is represented by '', both within and outside * of single-quoted segments. Inside a * messageFormatElement, quotes are <EM>not</EM> removed. For example, * {1,number,$'#',##} will produce a number format with the pound-sign * quoted, with a result such as: "$#31,45". * <P> * If a pattern is used, then unquoted braces in the pattern, if any, * must match: that is, "ab {0} de" and "ab '}' de" are ok, but "ab * {0'}' de" and "ab } de" are not. * <P> * The argumentIndex is a non-negative integer, which corresponds to the * index of the arguments presented in an array to be formatted. The * first argument has argumentIndex 0. * <P> * It is acceptable to have unused arguments in the array. With missing * arguments or arguments that are not of the right class for the * specified format, a failing UErrorCode result is set. * <P> * For more sophisticated patterns, you can use a ChoiceFormat to get * output: * <pre> * \code * UErrorCode success = U_ZERO_ERROR; * MessageFormat* form("The disk \"{1}\" contains {0}.", success); * double filelimits[] = {0,1,2}; * UnicodeString filepart[] = {"no files","one file","{0,number} files"}; * ChoiceFormat* fileform = new ChoiceFormat(filelimits, filepart, 3); * form.setFormat(1, *fileform); // NOT zero, see below * * Formattable testArgs[] = {1273L, "MyDisk"}; * * UnicodeString string; * FieldPosition fpos = 0; * cout << form.format(testArgs, 2, string, fpos, success) << endl; * * // output, with different testArgs * // output: The disk "MyDisk" contains no files. * // output: The disk "MyDisk" contains one file. * // output: The disk "MyDisk" contains 1,273 files. * \endcode * </pre> * You can either do this programmatically, as in the above example, * or by using a pattern (see ChoiceFormat for more information) as in: * <pre> * \code * form.applyPattern( * "There {0,choice,0#are no files|1#is one file|1<are {0,number,integer} files}."); * \endcode * </pre> * <P> * <EM>Note:</EM> As we see above, the string produced by a ChoiceFormat in * MessageFormat is treated specially; occurences of '{' are used to * indicated subformats, and cause recursion. If you create both a * MessageFormat and ChoiceFormat programmatically (instead of using * the string patterns), then be careful not to produce a format that * recurses on itself, which will cause an infinite loop. * <P> * <EM>Note:</EM> Subformats are numbered by their order in the pattern. * This is <EM>not</EM> the same as the argumentIndex. * <pre> * \code * For example: with "abc{2}def{3}ghi{0}...", * * format0 affects the first variable {2} * format1 affects the second variable {3} * format2 affects the second variable {0} * \endcode * </pre> * * <p><em>User subclasses are not supported.</em> While clients may write * subclasses, such code will not necessarily work and will not be * guaranteed to work stably from release to release. */ class U_I18N_API MessageFormat : public Format { public: /** * 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 }; /** * 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 recieve information on position * of 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 Format* clone(void) const; /** * 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 UBool operator==(const Format& other) const; /** * Sets the locale. This locale is used for fetching default number or date * format information. * @param theLocale the new locale value to be set. * @stable ICU 2.0 */ virtual void setLocale(const Locale& theLocale); /** * Gets the locale. This locale is used for fetching default number or date * format information. * @return the locale of the object. * @stable ICU 2.0 */ virtual const Locale& getLocale(void) 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 recieve information on position * of error within 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); /** * 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. * * @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. * * @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. * @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 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 any method of this class is made with * this object. 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 NULL if out of * memory. Any or all of the array elements may be NULL. * @stable ICU 2.0 */ virtual const Format** getFormats(int32_t& count) const; /** * Formats the given array of arguments into a user-readable string. * Does not take ownership of the Formattable* array or its contents. * * @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. * * @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. * * @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; /** * 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. * * @param obj The object to format * @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 */ UnicodeString& format(const Formattable& obj, 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. * * @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. * @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; /** * 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(void) const; /** * 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(void); private: Locale fLocale; UnicodeString fPattern; Format** formatAliases; // see getFormats int32_t formatAliasesCapacity; MessageFormat(); // default constructor not implemented /* * A structure representing one subformat of this MessageFormat. * Each subformat has a Format object, an offset into the plain * pattern text fPattern, and an argument number. The argument * number corresponds to the array of arguments to be formatted. * @internal */ class Subformat { public: /** * @internal */ Format* format; // formatter /** * @internal */ int32_t offset; // offset into fPattern /** * @internal */ int32_t arg; // 0-based argument number /** * Clone that.format and assign it to this.format * Do NOT delete this.format * @internal */ Subformat& operator=(const Subformat& that) { format = that.format ? that.format->clone() : NULL; offset = that.offset; arg = that.arg; return *this; } /** * @internal */ UBool operator==(const Subformat& that) const { // Do cheap comparisons first return offset == that.offset && arg == that.arg && ((format == that.format) || // handles NULL (*format == *that.format)); } /** * @internal */ UBool operator!=(const Subformat& that) const { return !operator==(that); } }; /** * A MessageFormat contains an array of subformats. This array * needs to grow dynamically if the MessageFormat is modified. */ Subformat* subformats; int32_t subformatCount; int32_t subformatCapacity; /** * 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; // Variable-size array management UBool allocateSubformats(int32_t capacity); UBool allocateArgTypes(int32_t capacity); /** * 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; /** * Method to retrieve default formats (or NULL 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 UChar * const *list); /** * Formats the array of arguments and copies the result into the * result buffer, updates the field position. * * @param arguments The formattable objects array. * @param cnt The array count. * @param appendTo Output parameter to receive result. * Result is appended to existing contents. * @param status Field position status. * @param recursionProtection * Initially zero. Bits 0..9 are used to indicate * that a parameter has already been seen, to * avoid recursion. Currently unused. * @param success The error code status. * @return Reference to 'appendTo' parameter. */ UnicodeString& format( const Formattable* arguments, int32_t cnt, UnicodeString& appendTo, FieldPosition& status, int32_t recursionProtection, UErrorCode& success) const; void makeFormat(int32_t offsetNumber, UnicodeString* segments, UParseError& parseError, UErrorCode& success); /** * Convenience method that ought to be in NumberFormat */ NumberFormat* createIntegerFormat(const Locale& locale, UErrorCode& status) const; /** * Checks the range of the source text to quote the special * characters, { and ' and copy to target buffer. * @param source * @param start the text offset to start the process of in the source string * @param end the text offset to end the process of in the source string * @param appendTo Output parameter to receive result. * Result is appended to existing contents. */ static void copyAndFixQuotes(const UnicodeString& appendTo, int32_t start, int32_t end, UnicodeString& target); /** * 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 * @internal */ const Formattable::Type* getArgTypeList(int32_t& listCount) const { listCount = argTypeCount; return argTypes; } friend class MessageFormatAdapter; // getFormatTypeList() access }; inline UnicodeString& MessageFormat::format(const Formattable& obj, UnicodeString& appendTo, UErrorCode& status) const { return Format::format(obj, appendTo, status); } U_NAMESPACE_END #endif /* #if !UCONFIG_NO_FORMATTING */ #endif // _MSGFMT //eof