/src/icu/source/common/unicode/simpleformatter.h

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// © 2016 and later: Unicode, Inc. and others.
// License & terms of use: http://www.unicode.org/copyright.html
/*
******************************************************************************
* Copyright (C) 2014-2016, International Business Machines
* Corporation and others.  All Rights Reserved.
******************************************************************************
* simpleformatter.h
*/

#ifndef __SIMPLEFORMATTER_H__
#define __SIMPLEFORMATTER_H__

/**
 * \file
 * \brief C++ API: Simple formatter, minimal subset of MessageFormat.
 */

#include "unicode/utypes.h"

#if U_SHOW_CPLUSPLUS_API

#include "unicode/unistr.h"

U_NAMESPACE_BEGIN

// Forward declaration:
namespace number {
namespace impl {
class SimpleModifier;
}
}

/**
 * Formats simple patterns like "{1} was born in {0}".
 * Minimal subset of MessageFormat; fast, simple, minimal dependencies.
 * Supports only numbered arguments with no type nor style parameters,
 * and formats only string values.
 * Quoting via ASCII apostrophe compatible with ICU MessageFormat default behavior.
 *
 * Factory methods set error codes for syntax errors
 * and for too few or too many arguments/placeholders.
 *
 * SimpleFormatter objects are thread-safe except for assignment and applying new patterns.
 *
 * Example:
 * <pre>
 * UErrorCode errorCode = U_ZERO_ERROR;
 * SimpleFormatter fmt("{1} '{born}' in {0}", errorCode);
 * UnicodeString result;
 *
 * // Output: "paul {born} in england"
 * fmt.format("england", "paul", result, errorCode);
 * </pre>
 *
 * This class is not intended for public subclassing.
 *
 * @see MessageFormat
 * @see UMessagePatternApostropheMode
 * @stable ICU 57
 */
class U_COMMON_API SimpleFormatter U_FINAL : public UMemory {
public:
    /**
     * Default constructor.
     * @stable ICU 57
     */
    SimpleFormatter() : compiledPattern((char16_t)0) {}

    /**
     * Constructs a formatter from the pattern string.
     *
     * @param pattern The pattern string.
     * @param errorCode ICU error code in/out parameter.
     *                  Must fulfill U_SUCCESS before the function call.
     *                  Set to U_ILLEGAL_ARGUMENT_ERROR for bad argument syntax.
     * @stable ICU 57
     */
    SimpleFormatter(const UnicodeString& pattern, UErrorCode &errorCode) {
        applyPattern(pattern, errorCode);
    }

    /**
     * Constructs a formatter from the pattern string.
     * The number of arguments checked against the given limits is the
     * highest argument number plus one, not the number of occurrences of arguments.
     *
     * @param pattern The pattern string.
     * @param min The pattern must have at least this many arguments.
     * @param max The pattern must have at most this many arguments.
     * @param errorCode ICU error code in/out parameter.
     *                  Must fulfill U_SUCCESS before the function call.
     *                  Set to U_ILLEGAL_ARGUMENT_ERROR for bad argument syntax and
     *                  too few or too many arguments.
     * @stable ICU 57
     */
    SimpleFormatter(const UnicodeString& pattern, int32_t min, int32_t max,
                    UErrorCode &errorCode) {
        applyPatternMinMaxArguments(pattern, min, max, errorCode);
    }

    /**
     * Copy constructor.
     * @stable ICU 57
     */
    SimpleFormatter(const SimpleFormatter& other)
            : compiledPattern(other.compiledPattern) {}

    /**
     * Assignment operator.
     * @stable ICU 57
     */
    SimpleFormatter &operator=(const SimpleFormatter& other);

    /**
     * Destructor.
     * @stable ICU 57
     */
    ~SimpleFormatter();

    /**
     * Changes this object according to the new pattern.
     *
     * @param pattern The pattern string.
     * @param errorCode ICU error code in/out parameter.
     *                  Must fulfill U_SUCCESS before the function call.
     *                  Set to U_ILLEGAL_ARGUMENT_ERROR for bad argument syntax.
     * @return true if U_SUCCESS(errorCode).
     * @stable ICU 57
     */
    UBool applyPattern(const UnicodeString &pattern, UErrorCode &errorCode) {
        return applyPatternMinMaxArguments(pattern, 0, INT32_MAX, errorCode);
    }

    /**
     * Changes this object according to the new pattern.
     * The number of arguments checked against the given limits is the
     * highest argument number plus one, not the number of occurrences of arguments.
     *
     * @param pattern The pattern string.
     * @param min The pattern must have at least this many arguments.
     * @param max The pattern must have at most this many arguments.
     * @param errorCode ICU error code in/out parameter.
     *                  Must fulfill U_SUCCESS before the function call.
     *                  Set to U_ILLEGAL_ARGUMENT_ERROR for bad argument syntax and
     *                  too few or too many arguments.
     * @return true if U_SUCCESS(errorCode).
     * @stable ICU 57
     */
    UBool applyPatternMinMaxArguments(const UnicodeString &pattern,
                                      int32_t min, int32_t max, UErrorCode &errorCode);

    /**
     * @return The max argument number + 1.
     * @stable ICU 57
     */
    int32_t getArgumentLimit() const {
        return getArgumentLimit(compiledPattern.getBuffer(), compiledPattern.length());
    }

    /**
     * Formats the given value, appending to the appendTo builder.
     * The argument value must not be the same object as appendTo.
     * getArgumentLimit() must be at most 1.
     *
     * @param value0 Value for argument {0}.
     * @param appendTo Gets the formatted pattern and value appended.
     * @param errorCode ICU error code in/out parameter.
     *                  Must fulfill U_SUCCESS before the function call.
     * @return appendTo
     * @stable ICU 57
     */
    UnicodeString &format(
            const UnicodeString &value0,
            UnicodeString &appendTo, UErrorCode &errorCode) const;

    /**
     * Formats the given values, appending to the appendTo builder.
     * An argument value must not be the same object as appendTo.
     * getArgumentLimit() must be at most 2.
     *
     * @param value0 Value for argument {0}.
     * @param value1 Value for argument {1}.
     * @param appendTo Gets the formatted pattern and values appended.
     * @param errorCode ICU error code in/out parameter.
     *                  Must fulfill U_SUCCESS before the function call.
     * @return appendTo
     * @stable ICU 57
     */
    UnicodeString &format(
            const UnicodeString &value0,
            const UnicodeString &value1,
            UnicodeString &appendTo, UErrorCode &errorCode) const;

    /**
     * Formats the given values, appending to the appendTo builder.
     * An argument value must not be the same object as appendTo.
     * getArgumentLimit() must be at most 3.
     *
     * @param value0 Value for argument {0}.
     * @param value1 Value for argument {1}.
     * @param value2 Value for argument {2}.
     * @param appendTo Gets the formatted pattern and values appended.
     * @param errorCode ICU error code in/out parameter.
     *                  Must fulfill U_SUCCESS before the function call.
     * @return appendTo
     * @stable ICU 57
     */
    UnicodeString &format(
            const UnicodeString &value0,
            const UnicodeString &value1,
            const UnicodeString &value2,
            UnicodeString &appendTo, UErrorCode &errorCode) const;

    /**
     * Formats the given values, appending to the appendTo string.
     *
     * @param values The argument values.
     *               An argument value must not be the same object as appendTo.
     *               Can be NULL if valuesLength==getArgumentLimit()==0.
     * @param valuesLength The length of the values array.
     *                     Must be at least getArgumentLimit().
     * @param appendTo Gets the formatted pattern and values appended.
     * @param offsets offsets[i] receives the offset of where
     *                values[i] replaced pattern argument {i}.
     *                Can be shorter or longer than values. Can be NULL if offsetsLength==0.
     *                If there is no {i} in the pattern, then offsets[i] is set to -1.
     * @param offsetsLength The length of the offsets array.
     * @param errorCode ICU error code in/out parameter.
     *                  Must fulfill U_SUCCESS before the function call.
     * @return appendTo
     * @stable ICU 57
     */
    UnicodeString &formatAndAppend(
            const UnicodeString *const *values, int32_t valuesLength,
            UnicodeString &appendTo,
            int32_t *offsets, int32_t offsetsLength, UErrorCode &errorCode) const;

    /**
     * Formats the given values, replacing the contents of the result string.
     * May optimize by actually appending to the result if it is the same object
     * as the value corresponding to the initial argument in the pattern.
     *
     * @param values The argument values.
     *               An argument value may be the same object as result.
     *               Can be NULL if valuesLength==getArgumentLimit()==0.
     * @param valuesLength The length of the values array.
     *                     Must be at least getArgumentLimit().
     * @param result Gets its contents replaced by the formatted pattern and values.
     * @param offsets offsets[i] receives the offset of where
     *                values[i] replaced pattern argument {i}.
     *                Can be shorter or longer than values. Can be NULL if offsetsLength==0.
     *                If there is no {i} in the pattern, then offsets[i] is set to -1.
     * @param offsetsLength The length of the offsets array.
     * @param errorCode ICU error code in/out parameter.
     *                  Must fulfill U_SUCCESS before the function call.
     * @return result
     * @stable ICU 57
     */
    UnicodeString &formatAndReplace(
            const UnicodeString *const *values, int32_t valuesLength,
            UnicodeString &result,
            int32_t *offsets, int32_t offsetsLength, UErrorCode &errorCode) const;

    /**
     * Returns the pattern text with none of the arguments.
     * Like formatting with all-empty string values.
     * @stable ICU 57
     */
    UnicodeString getTextWithNoArguments() const {
        return getTextWithNoArguments(
            compiledPattern.getBuffer(),
            compiledPattern.length(),
            nullptr,
            0);
    }

#ifndef U_HIDE_INTERNAL_API
    /**
     * Returns the pattern text with none of the arguments.
     * Like formatting with all-empty string values.
     *
     * TODO(ICU-20406): Replace this with an Iterator interface.
     *
     * @param offsets offsets[i] receives the offset of where {i} was located
     *                before it was replaced by an empty string.
     *                For example, "a{0}b{1}" produces offset 1 for i=0 and 2 for i=1.
     *                Can be nullptr if offsetsLength==0.
     *                If there is no {i} in the pattern, then offsets[i] is set to -1.
     * @param offsetsLength The length of the offsets array.
     *
     * @internal
     */
    UnicodeString getTextWithNoArguments(int32_t *offsets, int32_t offsetsLength) const {
        return getTextWithNoArguments(
            compiledPattern.getBuffer(),
            compiledPattern.length(),
            offsets,
            offsetsLength);
    }
#endif // U_HIDE_INTERNAL_API

private:
    /**
     * Binary representation of the compiled pattern.
     * Index 0: One more than the highest argument number.
     * Followed by zero or more arguments or literal-text segments.
     *
     * An argument is stored as its number, less than ARG_NUM_LIMIT.
     * A literal-text segment is stored as its length (at least 1) offset by ARG_NUM_LIMIT,
     * followed by that many chars.
     */
    UnicodeString compiledPattern;

    static inline int32_t getArgumentLimit(const char16_t *compiledPattern,
                                              int32_t compiledPatternLength) {
        return compiledPatternLength == 0 ? 0 : compiledPattern[0];
    }

    static UnicodeString getTextWithNoArguments(
        const char16_t *compiledPattern,
        int32_t compiledPatternLength,
        int32_t *offsets,
        int32_t offsetsLength);

    static UnicodeString &format(
            const char16_t *compiledPattern, int32_t compiledPatternLength,
            const UnicodeString *const *values,
            UnicodeString &result, const UnicodeString *resultCopy, UBool forbidResultAsValue,
            int32_t *offsets, int32_t offsetsLength,
            UErrorCode &errorCode);

    // Give access to internals to SimpleModifier for number formatting
    friend class number::impl::SimpleModifier;
};

U_NAMESPACE_END

#endif /* U_SHOW_CPLUSPLUS_API */

#endif  // __SIMPLEFORMATTER_H__

Coverage Report

Created: 2025-06-24 06:43

Line	Count	Source (jump to first uncovered line)
1		// © 2016 and later: Unicode, Inc. and others.
2		// License & terms of use: http://www.unicode.org/copyright.html
3		/*
4		******************************************************************************
5		* Copyright (C) 2014-2016, International Business Machines
6		* Corporation and others. All Rights Reserved.
7		******************************************************************************
8		* simpleformatter.h
9		*/
10
11		#ifndef __SIMPLEFORMATTER_H__
12		#define __SIMPLEFORMATTER_H__
13
14		/**
15		* \file
16		* \brief C++ API: Simple formatter, minimal subset of MessageFormat.
17		*/
18
19		#include "unicode/utypes.h"
20
21		#if U_SHOW_CPLUSPLUS_API
22
23		#include "unicode/unistr.h"
24
25		U_NAMESPACE_BEGIN
26
27		// Forward declaration:
28		namespace number {
29		namespace impl {
30		class SimpleModifier;
31		}
32		}
33
34		/**
35		* Formats simple patterns like "{1} was born in {0}".
36		* Minimal subset of MessageFormat; fast, simple, minimal dependencies.
37		* Supports only numbered arguments with no type nor style parameters,
38		* and formats only string values.
39		* Quoting via ASCII apostrophe compatible with ICU MessageFormat default behavior.
40		*
41		* Factory methods set error codes for syntax errors
42		* and for too few or too many arguments/placeholders.
43		*
44		* SimpleFormatter objects are thread-safe except for assignment and applying new patterns.
45		*
46		* Example:
47		* <pre>
48		* UErrorCode errorCode = U_ZERO_ERROR;
49		* SimpleFormatter fmt("{1} '{born}' in {0}", errorCode);
50		* UnicodeString result;
51		*
52		* // Output: "paul {born} in england"
53		* fmt.format("england", "paul", result, errorCode);
54		* </pre>
55		*
56		* This class is not intended for public subclassing.
57		*
58		* @see MessageFormat
59		* @see UMessagePatternApostropheMode
60		* @stable ICU 57
61		*/
62		class U_COMMON_API SimpleFormatter U_FINAL : public UMemory {
63		public:
64		/**
65		* Default constructor.
66		* @stable ICU 57
67		*/
68	0	SimpleFormatter() : compiledPattern((char16_t)0) {}
69
70		/**
71		* Constructs a formatter from the pattern string.
72		*
73		* @param pattern The pattern string.
74		* @param errorCode ICU error code in/out parameter.
75		* Must fulfill U_SUCCESS before the function call.
76		* Set to U_ILLEGAL_ARGUMENT_ERROR for bad argument syntax.
77		* @stable ICU 57
78		*/
79	0	SimpleFormatter(const UnicodeString& pattern, UErrorCode &errorCode) {
80	0	applyPattern(pattern, errorCode);
81	0	}
82
83		/**
84		* Constructs a formatter from the pattern string.
85		* The number of arguments checked against the given limits is the
86		* highest argument number plus one, not the number of occurrences of arguments.
87		*
88		* @param pattern The pattern string.
89		* @param min The pattern must have at least this many arguments.
90		* @param max The pattern must have at most this many arguments.
91		* @param errorCode ICU error code in/out parameter.
92		* Must fulfill U_SUCCESS before the function call.
93		* Set to U_ILLEGAL_ARGUMENT_ERROR for bad argument syntax and
94		* too few or too many arguments.
95		* @stable ICU 57
96		*/
97		SimpleFormatter(const UnicodeString& pattern, int32_t min, int32_t max,
98	0	UErrorCode &errorCode) {
99	0	applyPatternMinMaxArguments(pattern, min, max, errorCode);
100	0	}
101
102		/**
103		* Copy constructor.
104		* @stable ICU 57
105		*/
106		SimpleFormatter(const SimpleFormatter& other)
107	0	: compiledPattern(other.compiledPattern) {}
108
109		/**
110		* Assignment operator.
111		* @stable ICU 57
112		*/
113		SimpleFormatter &operator=(const SimpleFormatter& other);
114
115		/**
116		* Destructor.
117		* @stable ICU 57
118		*/
119		~SimpleFormatter();
120
121		/**
122		* Changes this object according to the new pattern.
123		*
124		* @param pattern The pattern string.
125		* @param errorCode ICU error code in/out parameter.
126		* Must fulfill U_SUCCESS before the function call.
127		* Set to U_ILLEGAL_ARGUMENT_ERROR for bad argument syntax.
128		* @return true if U_SUCCESS(errorCode).
129		* @stable ICU 57
130		*/
131	0	UBool applyPattern(const UnicodeString &pattern, UErrorCode &errorCode) {
132	0	return applyPatternMinMaxArguments(pattern, 0, INT32_MAX, errorCode);
133	0	}
134
135		/**
136		* Changes this object according to the new pattern.
137		* The number of arguments checked against the given limits is the
138		* highest argument number plus one, not the number of occurrences of arguments.
139		*
140		* @param pattern The pattern string.
141		* @param min The pattern must have at least this many arguments.
142		* @param max The pattern must have at most this many arguments.
143		* @param errorCode ICU error code in/out parameter.
144		* Must fulfill U_SUCCESS before the function call.
145		* Set to U_ILLEGAL_ARGUMENT_ERROR for bad argument syntax and
146		* too few or too many arguments.
147		* @return true if U_SUCCESS(errorCode).
148		* @stable ICU 57
149		*/
150		UBool applyPatternMinMaxArguments(const UnicodeString &pattern,
151		int32_t min, int32_t max, UErrorCode &errorCode);
152
153		/**
154		* @return The max argument number + 1.
155		* @stable ICU 57
156		*/
157	0	int32_t getArgumentLimit() const {
158	0	return getArgumentLimit(compiledPattern.getBuffer(), compiledPattern.length());
159	0	}
160
161		/**
162		* Formats the given value, appending to the appendTo builder.
163		* The argument value must not be the same object as appendTo.
164		* getArgumentLimit() must be at most 1.
165		*
166		* @param value0 Value for argument {0}.
167		* @param appendTo Gets the formatted pattern and value appended.
168		* @param errorCode ICU error code in/out parameter.
169		* Must fulfill U_SUCCESS before the function call.
170		* @return appendTo
171		* @stable ICU 57
172		*/
173		UnicodeString &format(
174		const UnicodeString &value0,
175		UnicodeString &appendTo, UErrorCode &errorCode) const;
176
177		/**
178		* Formats the given values, appending to the appendTo builder.
179		* An argument value must not be the same object as appendTo.
180		* getArgumentLimit() must be at most 2.
181		*
182		* @param value0 Value for argument {0}.
183		* @param value1 Value for argument {1}.
184		* @param appendTo Gets the formatted pattern and values appended.
185		* @param errorCode ICU error code in/out parameter.
186		* Must fulfill U_SUCCESS before the function call.
187		* @return appendTo
188		* @stable ICU 57
189		*/
190		UnicodeString &format(
191		const UnicodeString &value0,
192		const UnicodeString &value1,
193		UnicodeString &appendTo, UErrorCode &errorCode) const;
194
195		/**
196		* Formats the given values, appending to the appendTo builder.
197		* An argument value must not be the same object as appendTo.
198		* getArgumentLimit() must be at most 3.
199		*
200		* @param value0 Value for argument {0}.
201		* @param value1 Value for argument {1}.
202		* @param value2 Value for argument {2}.
203		* @param appendTo Gets the formatted pattern and values appended.
204		* @param errorCode ICU error code in/out parameter.
205		* Must fulfill U_SUCCESS before the function call.
206		* @return appendTo
207		* @stable ICU 57
208		*/
209		UnicodeString &format(
210		const UnicodeString &value0,
211		const UnicodeString &value1,
212		const UnicodeString &value2,
213		UnicodeString &appendTo, UErrorCode &errorCode) const;
214
215		/**
216		* Formats the given values, appending to the appendTo string.
217		*
218		* @param values The argument values.
219		* An argument value must not be the same object as appendTo.
220		* Can be NULL if valuesLength==getArgumentLimit()==0.
221		* @param valuesLength The length of the values array.
222		* Must be at least getArgumentLimit().
223		* @param appendTo Gets the formatted pattern and values appended.
224		* @param offsets offsets[i] receives the offset of where
225		* values[i] replaced pattern argument {i}.
226		* Can be shorter or longer than values. Can be NULL if offsetsLength==0.
227		* If there is no {i} in the pattern, then offsets[i] is set to -1.
228		* @param offsetsLength The length of the offsets array.
229		* @param errorCode ICU error code in/out parameter.
230		* Must fulfill U_SUCCESS before the function call.
231		* @return appendTo
232		* @stable ICU 57
233		*/
234		UnicodeString &formatAndAppend(
235		const UnicodeString const values, int32_t valuesLength,
236		UnicodeString &appendTo,
237		int32_t *offsets, int32_t offsetsLength, UErrorCode &errorCode) const;
238
239		/**
240		* Formats the given values, replacing the contents of the result string.
241		* May optimize by actually appending to the result if it is the same object
242		* as the value corresponding to the initial argument in the pattern.
243		*
244		* @param values The argument values.
245		* An argument value may be the same object as result.
246		* Can be NULL if valuesLength==getArgumentLimit()==0.
247		* @param valuesLength The length of the values array.
248		* Must be at least getArgumentLimit().
249		* @param result Gets its contents replaced by the formatted pattern and values.
250		* @param offsets offsets[i] receives the offset of where
251		* values[i] replaced pattern argument {i}.
252		* Can be shorter or longer than values. Can be NULL if offsetsLength==0.
253		* If there is no {i} in the pattern, then offsets[i] is set to -1.
254		* @param offsetsLength The length of the offsets array.
255		* @param errorCode ICU error code in/out parameter.
256		* Must fulfill U_SUCCESS before the function call.
257		* @return result
258		* @stable ICU 57
259		*/
260		UnicodeString &formatAndReplace(
261		const UnicodeString const values, int32_t valuesLength,
262		UnicodeString &result,
263		int32_t *offsets, int32_t offsetsLength, UErrorCode &errorCode) const;
264
265		/**
266		* Returns the pattern text with none of the arguments.
267		* Like formatting with all-empty string values.
268		* @stable ICU 57
269		*/
270	0	UnicodeString getTextWithNoArguments() const {
271	0	return getTextWithNoArguments(
272	0	compiledPattern.getBuffer(),
273	0	compiledPattern.length(),
274	0	nullptr,
275	0	0);
276	0	}
277
278		#ifndef U_HIDE_INTERNAL_API
279		/**
280		* Returns the pattern text with none of the arguments.
281		* Like formatting with all-empty string values.
282		*
283		* TODO(ICU-20406): Replace this with an Iterator interface.
284		*
285		* @param offsets offsets[i] receives the offset of where {i} was located
286		* before it was replaced by an empty string.
287		* For example, "a{0}b{1}" produces offset 1 for i=0 and 2 for i=1.
288		* Can be nullptr if offsetsLength==0.
289		* If there is no {i} in the pattern, then offsets[i] is set to -1.
290		* @param offsetsLength The length of the offsets array.
291		*
292		* @internal
293		*/
294	0	UnicodeString getTextWithNoArguments(int32_t *offsets, int32_t offsetsLength) const {
295	0	return getTextWithNoArguments(
296	0	compiledPattern.getBuffer(),
297	0	compiledPattern.length(),
298	0	offsets,
299	0	offsetsLength);
300	0	}
301		#endif // U_HIDE_INTERNAL_API
302
303		private:
304		/**
305		* Binary representation of the compiled pattern.
306		* Index 0: One more than the highest argument number.
307		* Followed by zero or more arguments or literal-text segments.
308		*
309		* An argument is stored as its number, less than ARG_NUM_LIMIT.
310		* A literal-text segment is stored as its length (at least 1) offset by ARG_NUM_LIMIT,
311		* followed by that many chars.
312		*/
313		UnicodeString compiledPattern;
314
315		static inline int32_t getArgumentLimit(const char16_t *compiledPattern,
316	0	int32_t compiledPatternLength) {
317	0	return compiledPatternLength == 0 ? 0 : compiledPattern[0];
318	0	}
319
320		static UnicodeString getTextWithNoArguments(
321		const char16_t *compiledPattern,
322		int32_t compiledPatternLength,
323		int32_t *offsets,
324		int32_t offsetsLength);
325
326		static UnicodeString &format(
327		const char16_t *compiledPattern, int32_t compiledPatternLength,
328		const UnicodeString const values,
329		UnicodeString &result, const UnicodeString *resultCopy, UBool forbidResultAsValue,
330		int32_t *offsets, int32_t offsetsLength,
331		UErrorCode &errorCode);
332
333		// Give access to internals to SimpleModifier for number formatting
334		friend class number::impl::SimpleModifier;
335		};
336
337		U_NAMESPACE_END
338
339		#endif /* U_SHOW_CPLUSPLUS_API */
340
341		#endif // __SIMPLEFORMATTER_H__