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

Source (jump to first uncovered line)
// © 2016 and later: Unicode, Inc. and others.
// License & terms of use: http://www.unicode.org/copyright.html
/*
*******************************************************************************
*   Copyright (C) 2011-2012, International Business Machines
*   Corporation and others.  All Rights Reserved.
*******************************************************************************
*   file name:  appendable.h
*   encoding:   UTF-8
*   tab size:   8 (not used)
*   indentation:4
*
*   created on: 2010dec07
*   created by: Markus W. Scherer
*/

#ifndef __APPENDABLE_H__
#define __APPENDABLE_H__

/**
 * \file
 * \brief C++ API: Appendable class: Sink for Unicode code points and 16-bit code units (char16_ts).
 */

#include "unicode/utypes.h"
#include "unicode/uobject.h"

U_NAMESPACE_BEGIN

class UnicodeString;

/**
 * Base class for objects to which Unicode characters and strings can be appended.
 * Combines elements of Java Appendable and ICU4C ByteSink.
 *
 * This class can be used in APIs where it does not matter whether the actual destination is
 * a UnicodeString, a char16_t[] array, a UnicodeSet, or any other object
 * that receives and processes characters and/or strings.
 *
 * Implementation classes must implement at least appendCodeUnit(char16_t).
 * The base class provides default implementations for the other methods.
 *
 * The methods do not take UErrorCode parameters.
 * If an error occurs (e.g., out-of-memory),
 * in addition to returning FALSE from failing operations,
 * the implementation must prevent unexpected behavior (e.g., crashes)
 * from further calls and should make the error condition available separately
 * (e.g., store a UErrorCode, make/keep a UnicodeString bogus).
 * @stable ICU 4.8
 */
class U_COMMON_API Appendable : public UObject {
public:
    /**
     * Destructor.
     * @stable ICU 4.8
     */
    ~Appendable();

    /**
     * Appends a 16-bit code unit.
     * @param c code unit
     * @return TRUE if the operation succeeded
     * @stable ICU 4.8
     */
    virtual UBool appendCodeUnit(char16_t c) = 0;

    /**
     * Appends a code point.
     * The default implementation calls appendCodeUnit(char16_t) once or twice.
     * @param c code point 0..0x10ffff
     * @return TRUE if the operation succeeded
     * @stable ICU 4.8
     */
    virtual UBool appendCodePoint(UChar32 c);

    /**
     * Appends a string.
     * The default implementation calls appendCodeUnit(char16_t) for each code unit.
     * @param s string, must not be NULL if length!=0
     * @param length string length, or -1 if NUL-terminated
     * @return TRUE if the operation succeeded
     * @stable ICU 4.8
     */
    virtual UBool appendString(const char16_t *s, int32_t length);

    /**
     * Tells the object that the caller is going to append roughly
     * appendCapacity char16_ts. A subclass might use this to pre-allocate
     * a larger buffer if necessary.
     * The default implementation does nothing. (It always returns TRUE.)
     * @param appendCapacity estimated number of char16_ts that will be appended
     * @return TRUE if the operation succeeded
     * @stable ICU 4.8
     */
    virtual UBool reserveAppendCapacity(int32_t appendCapacity);

    /**
     * Returns a writable buffer for appending and writes the buffer's capacity to
     * *resultCapacity. Guarantees *resultCapacity>=minCapacity.
     * May return a pointer to the caller-owned scratch buffer which must have
     * scratchCapacity>=minCapacity.
     * The returned buffer is only valid until the next operation
     * on this Appendable.
     *
     * After writing at most *resultCapacity char16_ts, call appendString() with the
     * pointer returned from this function and the number of char16_ts written.
     * Many appendString() implementations will avoid copying char16_ts if this function
     * returned an internal buffer.
     *
     * Partial usage example:
     * \code
     *  int32_t capacity;
     *  char16_t* buffer = app.getAppendBuffer(..., &capacity);
     *  ... Write n char16_ts into buffer, with n <= capacity.
     *  app.appendString(buffer, n);
     * \endcode
     * In many implementations, that call to append will avoid copying char16_ts.
     *
     * If the Appendable allocates or reallocates an internal buffer, it should use
     * the desiredCapacityHint if appropriate.
     * If a caller cannot provide a reasonable guess at the desired capacity,
     * it should pass desiredCapacityHint=0.
     *
     * If a non-scratch buffer is returned, the caller may only pass
     * a prefix to it to appendString().
     * That is, it is not correct to pass an interior pointer to appendString().
     *
     * The default implementation always returns the scratch buffer.
     *
     * @param minCapacity required minimum capacity of the returned buffer;
     *                    must be non-negative
     * @param desiredCapacityHint desired capacity of the returned buffer;
     *                            must be non-negative
     * @param scratch default caller-owned buffer
     * @param scratchCapacity capacity of the scratch buffer
     * @param resultCapacity pointer to an integer which will be set to the
     *                       capacity of the returned buffer
     * @return a buffer with *resultCapacity>=minCapacity
     * @stable ICU 4.8
     */
    virtual char16_t *getAppendBuffer(int32_t minCapacity,
                                   int32_t desiredCapacityHint,
                                   char16_t *scratch, int32_t scratchCapacity,
                                   int32_t *resultCapacity);
};

/**
 * An Appendable implementation which writes to a UnicodeString.
 *
 * This class is not intended for public subclassing.
 * @stable ICU 4.8
 */
class U_COMMON_API UnicodeStringAppendable : public Appendable {
public:
    /**
     * Aliases the UnicodeString (keeps its reference) for writing.
     * @param s The UnicodeString to which this Appendable will write.
     * @stable ICU 4.8
     */
    explicit UnicodeStringAppendable(UnicodeString &s) : str(s) {}

    /**
     * Destructor.
     * @stable ICU 4.8
     */
    ~UnicodeStringAppendable();

    /**
     * Appends a 16-bit code unit to the string.
     * @param c code unit
     * @return TRUE if the operation succeeded
     * @stable ICU 4.8
     */
    virtual UBool appendCodeUnit(char16_t c);

    /**
     * Appends a code point to the string.
     * @param c code point 0..0x10ffff
     * @return TRUE if the operation succeeded
     * @stable ICU 4.8
     */
    virtual UBool appendCodePoint(UChar32 c);

    /**
     * Appends a string to the UnicodeString.
     * @param s string, must not be NULL if length!=0
     * @param length string length, or -1 if NUL-terminated
     * @return TRUE if the operation succeeded
     * @stable ICU 4.8
     */
    virtual UBool appendString(const char16_t *s, int32_t length);

    /**
     * Tells the UnicodeString that the caller is going to append roughly
     * appendCapacity char16_ts.
     * @param appendCapacity estimated number of char16_ts that will be appended
     * @return TRUE if the operation succeeded
     * @stable ICU 4.8
     */
    virtual UBool reserveAppendCapacity(int32_t appendCapacity);

    /**
     * Returns a writable buffer for appending and writes the buffer's capacity to
     * *resultCapacity. Guarantees *resultCapacity>=minCapacity.
     * May return a pointer to the caller-owned scratch buffer which must have
     * scratchCapacity>=minCapacity.
     * The returned buffer is only valid until the next write operation
     * on the UnicodeString.
     *
     * For details see Appendable::getAppendBuffer().
     *
     * @param minCapacity required minimum capacity of the returned buffer;
     *                    must be non-negative
     * @param desiredCapacityHint desired capacity of the returned buffer;
     *                            must be non-negative
     * @param scratch default caller-owned buffer
     * @param scratchCapacity capacity of the scratch buffer
     * @param resultCapacity pointer to an integer which will be set to the
     *                       capacity of the returned buffer
     * @return a buffer with *resultCapacity>=minCapacity
     * @stable ICU 4.8
     */
    virtual char16_t *getAppendBuffer(int32_t minCapacity,
                                   int32_t desiredCapacityHint,
                                   char16_t *scratch, int32_t scratchCapacity,
                                   int32_t *resultCapacity);

private:
    UnicodeString &str;
};

U_NAMESPACE_END

#endif  // __APPENDABLE_H__

Coverage Report

Created: 2025-07-11 06:23

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) 2011-2012, International Business Machines
6		* Corporation and others. All Rights Reserved.
7		*******************************************************************************
8		* file name: appendable.h
9		* encoding: UTF-8
10		* tab size: 8 (not used)
11		* indentation:4
12		*
13		* created on: 2010dec07
14		* created by: Markus W. Scherer
15		*/
16
17		#ifndef __APPENDABLE_H__
18		#define __APPENDABLE_H__
19
20		/**
21		* \file
22		* \brief C++ API: Appendable class: Sink for Unicode code points and 16-bit code units (char16_ts).
23		*/
24
25		#include "unicode/utypes.h"
26		#include "unicode/uobject.h"
27
28		U_NAMESPACE_BEGIN
29
30		class UnicodeString;
31
32		/**
33		* Base class for objects to which Unicode characters and strings can be appended.
34		* Combines elements of Java Appendable and ICU4C ByteSink.
35		*
36		* This class can be used in APIs where it does not matter whether the actual destination is
37		* a UnicodeString, a char16_t[] array, a UnicodeSet, or any other object
38		* that receives and processes characters and/or strings.
39		*
40		* Implementation classes must implement at least appendCodeUnit(char16_t).
41		* The base class provides default implementations for the other methods.
42		*
43		* The methods do not take UErrorCode parameters.
44		* If an error occurs (e.g., out-of-memory),
45		* in addition to returning FALSE from failing operations,
46		* the implementation must prevent unexpected behavior (e.g., crashes)
47		* from further calls and should make the error condition available separately
48		* (e.g., store a UErrorCode, make/keep a UnicodeString bogus).
49		* @stable ICU 4.8
50		*/
51		class U_COMMON_API Appendable : public UObject {
52		public:
53		/**
54		* Destructor.
55		* @stable ICU 4.8
56		*/
57		~Appendable();
58
59		/**
60		* Appends a 16-bit code unit.
61		* @param c code unit
62		* @return TRUE if the operation succeeded
63		* @stable ICU 4.8
64		*/
65		virtual UBool appendCodeUnit(char16_t c) = 0;
66
67		/**
68		* Appends a code point.
69		* The default implementation calls appendCodeUnit(char16_t) once or twice.
70		* @param c code point 0..0x10ffff
71		* @return TRUE if the operation succeeded
72		* @stable ICU 4.8
73		*/
74		virtual UBool appendCodePoint(UChar32 c);
75
76		/**
77		* Appends a string.
78		* The default implementation calls appendCodeUnit(char16_t) for each code unit.
79		* @param s string, must not be NULL if length!=0
80		* @param length string length, or -1 if NUL-terminated
81		* @return TRUE if the operation succeeded
82		* @stable ICU 4.8
83		*/
84		virtual UBool appendString(const char16_t *s, int32_t length);
85
86		/**
87		* Tells the object that the caller is going to append roughly
88		* appendCapacity char16_ts. A subclass might use this to pre-allocate
89		* a larger buffer if necessary.
90		* The default implementation does nothing. (It always returns TRUE.)
91		* @param appendCapacity estimated number of char16_ts that will be appended
92		* @return TRUE if the operation succeeded
93		* @stable ICU 4.8
94		*/
95		virtual UBool reserveAppendCapacity(int32_t appendCapacity);
96
97		/**
98		* Returns a writable buffer for appending and writes the buffer's capacity to
99		* resultCapacity. Guarantees resultCapacity>=minCapacity.
100		* May return a pointer to the caller-owned scratch buffer which must have
101		* scratchCapacity>=minCapacity.
102		* The returned buffer is only valid until the next operation
103		* on this Appendable.
104		*
105		* After writing at most *resultCapacity char16_ts, call appendString() with the
106		* pointer returned from this function and the number of char16_ts written.
107		* Many appendString() implementations will avoid copying char16_ts if this function
108		* returned an internal buffer.
109		*
110		* Partial usage example:
111		* \code
112		* int32_t capacity;
113		* char16_t* buffer = app.getAppendBuffer(..., &capacity);
114		* ... Write n char16_ts into buffer, with n <= capacity.
115		* app.appendString(buffer, n);
116		* \endcode
117		* In many implementations, that call to append will avoid copying char16_ts.
118		*
119		* If the Appendable allocates or reallocates an internal buffer, it should use
120		* the desiredCapacityHint if appropriate.
121		* If a caller cannot provide a reasonable guess at the desired capacity,
122		* it should pass desiredCapacityHint=0.
123		*
124		* If a non-scratch buffer is returned, the caller may only pass
125		* a prefix to it to appendString().
126		* That is, it is not correct to pass an interior pointer to appendString().
127		*
128		* The default implementation always returns the scratch buffer.
129		*
130		* @param minCapacity required minimum capacity of the returned buffer;
131		* must be non-negative
132		* @param desiredCapacityHint desired capacity of the returned buffer;
133		* must be non-negative
134		* @param scratch default caller-owned buffer
135		* @param scratchCapacity capacity of the scratch buffer
136		* @param resultCapacity pointer to an integer which will be set to the
137		* capacity of the returned buffer
138		* @return a buffer with *resultCapacity>=minCapacity
139		* @stable ICU 4.8
140		*/
141		virtual char16_t *getAppendBuffer(int32_t minCapacity,
142		int32_t desiredCapacityHint,
143		char16_t *scratch, int32_t scratchCapacity,
144		int32_t *resultCapacity);
145		};
146
147		/**
148		* An Appendable implementation which writes to a UnicodeString.
149		*
150		* This class is not intended for public subclassing.
151		* @stable ICU 4.8
152		*/
153		class U_COMMON_API UnicodeStringAppendable : public Appendable {
154		public:
155		/**
156		* Aliases the UnicodeString (keeps its reference) for writing.
157		* @param s The UnicodeString to which this Appendable will write.
158		* @stable ICU 4.8
159		*/
160	0	explicit UnicodeStringAppendable(UnicodeString &s) : str(s) {}
161
162		/**
163		* Destructor.
164		* @stable ICU 4.8
165		*/
166		~UnicodeStringAppendable();
167
168		/**
169		* Appends a 16-bit code unit to the string.
170		* @param c code unit
171		* @return TRUE if the operation succeeded
172		* @stable ICU 4.8
173		*/
174		virtual UBool appendCodeUnit(char16_t c);
175
176		/**
177		* Appends a code point to the string.
178		* @param c code point 0..0x10ffff
179		* @return TRUE if the operation succeeded
180		* @stable ICU 4.8
181		*/
182		virtual UBool appendCodePoint(UChar32 c);
183
184		/**
185		* Appends a string to the UnicodeString.
186		* @param s string, must not be NULL if length!=0
187		* @param length string length, or -1 if NUL-terminated
188		* @return TRUE if the operation succeeded
189		* @stable ICU 4.8
190		*/
191		virtual UBool appendString(const char16_t *s, int32_t length);
192
193		/**
194		* Tells the UnicodeString that the caller is going to append roughly
195		* appendCapacity char16_ts.
196		* @param appendCapacity estimated number of char16_ts that will be appended
197		* @return TRUE if the operation succeeded
198		* @stable ICU 4.8
199		*/
200		virtual UBool reserveAppendCapacity(int32_t appendCapacity);
201
202		/**
203		* Returns a writable buffer for appending and writes the buffer's capacity to
204		* resultCapacity. Guarantees resultCapacity>=minCapacity.
205		* May return a pointer to the caller-owned scratch buffer which must have
206		* scratchCapacity>=minCapacity.
207		* The returned buffer is only valid until the next write operation
208		* on the UnicodeString.
209		*
210		* For details see Appendable::getAppendBuffer().
211		*
212		* @param minCapacity required minimum capacity of the returned buffer;
213		* must be non-negative
214		* @param desiredCapacityHint desired capacity of the returned buffer;
215		* must be non-negative
216		* @param scratch default caller-owned buffer
217		* @param scratchCapacity capacity of the scratch buffer
218		* @param resultCapacity pointer to an integer which will be set to the
219		* capacity of the returned buffer
220		* @return a buffer with *resultCapacity>=minCapacity
221		* @stable ICU 4.8
222		*/
223		virtual char16_t *getAppendBuffer(int32_t minCapacity,
224		int32_t desiredCapacityHint,
225		char16_t *scratch, int32_t scratchCapacity,
226		int32_t *resultCapacity);
227
228		private:
229		UnicodeString &str;
230		};
231
232		U_NAMESPACE_END
233
234		#endif // __APPENDABLE_H__