intl/icu/source/common/unicode/strenum.h

Wed, 31 Dec 2014 06:09:35 +0100

author
Michael Schloh von Bennewitz <michael@schloh.com>
date
Wed, 31 Dec 2014 06:09:35 +0100
changeset 0
6474c204b198
permissions
-rw-r--r--

Cloned upstream origin tor-browser at tor-browser-31.3.0esr-4.5-1-build1
revision ID fc1c9ff7c1b2defdbc039f12214767608f46423f for hacking purpose.

michael@0 1 /*
michael@0 2 *******************************************************************************
michael@0 3 *
michael@0 4 * Copyright (C) 2002-2012, International Business Machines
michael@0 5 * Corporation and others. All Rights Reserved.
michael@0 6 *
michael@0 7 *******************************************************************************
michael@0 8 */
michael@0 9
michael@0 10 #ifndef STRENUM_H
michael@0 11 #define STRENUM_H
michael@0 12
michael@0 13 #include "unicode/uobject.h"
michael@0 14 #include "unicode/unistr.h"
michael@0 15
michael@0 16 /**
michael@0 17 * \file
michael@0 18 * \brief C++ API: String Enumeration
michael@0 19 */
michael@0 20
michael@0 21 U_NAMESPACE_BEGIN
michael@0 22
michael@0 23 /**
michael@0 24 * Base class for 'pure' C++ implementations of uenum api. Adds a
michael@0 25 * method that returns the next UnicodeString since in C++ this can
michael@0 26 * be a common storage format for strings.
michael@0 27 *
michael@0 28 * <p>The model is that the enumeration is over strings maintained by
michael@0 29 * a 'service.' At any point, the service might change, invalidating
michael@0 30 * the enumerator (though this is expected to be rare). The iterator
michael@0 31 * returns an error if this has occurred. Lack of the error is no
michael@0 32 * guarantee that the service didn't change immediately after the
michael@0 33 * call, so the returned string still might not be 'valid' on
michael@0 34 * subsequent use.</p>
michael@0 35 *
michael@0 36 * <p>Strings may take the form of const char*, const UChar*, or const
michael@0 37 * UnicodeString*. The type you get is determine by the variant of
michael@0 38 * 'next' that you call. In general the StringEnumeration is
michael@0 39 * optimized for one of these types, but all StringEnumerations can
michael@0 40 * return all types. Returned strings are each terminated with a NUL.
michael@0 41 * Depending on the service data, they might also include embedded NUL
michael@0 42 * characters, so API is provided to optionally return the true
michael@0 43 * length, counting the embedded NULs but not counting the terminating
michael@0 44 * NUL.</p>
michael@0 45 *
michael@0 46 * <p>The pointers returned by next, unext, and snext become invalid
michael@0 47 * upon any subsequent call to the enumeration's destructor, next,
michael@0 48 * unext, snext, or reset.</p>
michael@0 49 *
michael@0 50 * ICU 2.8 adds some default implementations and helper functions
michael@0 51 * for subclasses.
michael@0 52 *
michael@0 53 * @stable ICU 2.4
michael@0 54 */
michael@0 55 class U_COMMON_API StringEnumeration : public UObject {
michael@0 56 public:
michael@0 57 /**
michael@0 58 * Destructor.
michael@0 59 * @stable ICU 2.4
michael@0 60 */
michael@0 61 virtual ~StringEnumeration();
michael@0 62
michael@0 63 /**
michael@0 64 * Clone this object, an instance of a subclass of StringEnumeration.
michael@0 65 * Clones can be used concurrently in multiple threads.
michael@0 66 * If a subclass does not implement clone(), or if an error occurs,
michael@0 67 * then NULL is returned.
michael@0 68 * The clone functions in all subclasses return a base class pointer
michael@0 69 * because some compilers do not support covariant (same-as-this)
michael@0 70 * return types; cast to the appropriate subclass if necessary.
michael@0 71 * The caller must delete the clone.
michael@0 72 *
michael@0 73 * @return a clone of this object
michael@0 74 *
michael@0 75 * @see getDynamicClassID
michael@0 76 * @stable ICU 2.8
michael@0 77 */
michael@0 78 virtual StringEnumeration *clone() const;
michael@0 79
michael@0 80 /**
michael@0 81 * <p>Return the number of elements that the iterator traverses. If
michael@0 82 * the iterator is out of sync with its service, status is set to
michael@0 83 * U_ENUM_OUT_OF_SYNC_ERROR, and the return value is zero.</p>
michael@0 84 *
michael@0 85 * <p>The return value will not change except possibly as a result of
michael@0 86 * a subsequent call to reset, or if the iterator becomes out of sync.</p>
michael@0 87 *
michael@0 88 * <p>This is a convenience function. It can end up being very
michael@0 89 * expensive as all the items might have to be pre-fetched
michael@0 90 * (depending on the storage format of the data being
michael@0 91 * traversed).</p>
michael@0 92 *
michael@0 93 * @param status the error code.
michael@0 94 * @return number of elements in the iterator.
michael@0 95 *
michael@0 96 * @stable ICU 2.4 */
michael@0 97 virtual int32_t count(UErrorCode& status) const = 0;
michael@0 98
michael@0 99 /**
michael@0 100 * <p>Returns the next element as a NUL-terminated char*. If there
michael@0 101 * are no more elements, returns NULL. If the resultLength pointer
michael@0 102 * is not NULL, the length of the string (not counting the
michael@0 103 * terminating NUL) is returned at that address. If an error
michael@0 104 * status is returned, the value at resultLength is undefined.</p>
michael@0 105 *
michael@0 106 * <p>The returned pointer is owned by this iterator and must not be
michael@0 107 * deleted by the caller. The pointer is valid until the next call
michael@0 108 * to next, unext, snext, reset, or the enumerator's destructor.</p>
michael@0 109 *
michael@0 110 * <p>If the iterator is out of sync with its service, status is set
michael@0 111 * to U_ENUM_OUT_OF_SYNC_ERROR and NULL is returned.</p>
michael@0 112 *
michael@0 113 * <p>If the native service string is a UChar* string, it is
michael@0 114 * converted to char* with the invariant converter. If the
michael@0 115 * conversion fails (because a character cannot be converted) then
michael@0 116 * status is set to U_INVARIANT_CONVERSION_ERROR and the return
michael@0 117 * value is undefined (though not NULL).</p>
michael@0 118 *
michael@0 119 * Starting with ICU 2.8, the default implementation calls snext()
michael@0 120 * and handles the conversion.
michael@0 121 * Either next() or snext() must be implemented differently by a subclass.
michael@0 122 *
michael@0 123 * @param status the error code.
michael@0 124 * @param resultLength a pointer to receive the length, can be NULL.
michael@0 125 * @return a pointer to the string, or NULL.
michael@0 126 *
michael@0 127 * @stable ICU 2.4
michael@0 128 */
michael@0 129 virtual const char* next(int32_t *resultLength, UErrorCode& status);
michael@0 130
michael@0 131 /**
michael@0 132 * <p>Returns the next element as a NUL-terminated UChar*. If there
michael@0 133 * are no more elements, returns NULL. If the resultLength pointer
michael@0 134 * is not NULL, the length of the string (not counting the
michael@0 135 * terminating NUL) is returned at that address. If an error
michael@0 136 * status is returned, the value at resultLength is undefined.</p>
michael@0 137 *
michael@0 138 * <p>The returned pointer is owned by this iterator and must not be
michael@0 139 * deleted by the caller. The pointer is valid until the next call
michael@0 140 * to next, unext, snext, reset, or the enumerator's destructor.</p>
michael@0 141 *
michael@0 142 * <p>If the iterator is out of sync with its service, status is set
michael@0 143 * to U_ENUM_OUT_OF_SYNC_ERROR and NULL is returned.</p>
michael@0 144 *
michael@0 145 * Starting with ICU 2.8, the default implementation calls snext()
michael@0 146 * and handles the conversion.
michael@0 147 *
michael@0 148 * @param status the error code.
michael@0 149 * @param resultLength a ponter to receive the length, can be NULL.
michael@0 150 * @return a pointer to the string, or NULL.
michael@0 151 *
michael@0 152 * @stable ICU 2.4
michael@0 153 */
michael@0 154 virtual const UChar* unext(int32_t *resultLength, UErrorCode& status);
michael@0 155
michael@0 156 /**
michael@0 157 * <p>Returns the next element a UnicodeString*. If there are no
michael@0 158 * more elements, returns NULL.</p>
michael@0 159 *
michael@0 160 * <p>The returned pointer is owned by this iterator and must not be
michael@0 161 * deleted by the caller. The pointer is valid until the next call
michael@0 162 * to next, unext, snext, reset, or the enumerator's destructor.</p>
michael@0 163 *
michael@0 164 * <p>If the iterator is out of sync with its service, status is set
michael@0 165 * to U_ENUM_OUT_OF_SYNC_ERROR and NULL is returned.</p>
michael@0 166 *
michael@0 167 * Starting with ICU 2.8, the default implementation calls next()
michael@0 168 * and handles the conversion.
michael@0 169 * Either next() or snext() must be implemented differently by a subclass.
michael@0 170 *
michael@0 171 * @param status the error code.
michael@0 172 * @return a pointer to the string, or NULL.
michael@0 173 *
michael@0 174 * @stable ICU 2.4
michael@0 175 */
michael@0 176 virtual const UnicodeString* snext(UErrorCode& status);
michael@0 177
michael@0 178 /**
michael@0 179 * <p>Resets the iterator. This re-establishes sync with the
michael@0 180 * service and rewinds the iterator to start at the first
michael@0 181 * element.</p>
michael@0 182 *
michael@0 183 * <p>Previous pointers returned by next, unext, or snext become
michael@0 184 * invalid, and the value returned by count might change.</p>
michael@0 185 *
michael@0 186 * @param status the error code.
michael@0 187 *
michael@0 188 * @stable ICU 2.4
michael@0 189 */
michael@0 190 virtual void reset(UErrorCode& status) = 0;
michael@0 191
michael@0 192 /**
michael@0 193 * Compares this enumeration to other to check if both are equal
michael@0 194 *
michael@0 195 * @param that The other string enumeration to compare this object to
michael@0 196 * @return TRUE if the enumerations are equal. FALSE if not.
michael@0 197 * @stable ICU 3.6
michael@0 198 */
michael@0 199 virtual UBool operator==(const StringEnumeration& that)const;
michael@0 200 /**
michael@0 201 * Compares this enumeration to other to check if both are not equal
michael@0 202 *
michael@0 203 * @param that The other string enumeration to compare this object to
michael@0 204 * @return TRUE if the enumerations are equal. FALSE if not.
michael@0 205 * @stable ICU 3.6
michael@0 206 */
michael@0 207 virtual UBool operator!=(const StringEnumeration& that)const;
michael@0 208
michael@0 209 protected:
michael@0 210 /**
michael@0 211 * UnicodeString field for use with default implementations and subclasses.
michael@0 212 * @stable ICU 2.8
michael@0 213 */
michael@0 214 UnicodeString unistr;
michael@0 215 /**
michael@0 216 * char * default buffer for use with default implementations and subclasses.
michael@0 217 * @stable ICU 2.8
michael@0 218 */
michael@0 219 char charsBuffer[32];
michael@0 220 /**
michael@0 221 * char * buffer for use with default implementations and subclasses.
michael@0 222 * Allocated in constructor and in ensureCharsCapacity().
michael@0 223 * @stable ICU 2.8
michael@0 224 */
michael@0 225 char *chars;
michael@0 226 /**
michael@0 227 * Capacity of chars, for use with default implementations and subclasses.
michael@0 228 * @stable ICU 2.8
michael@0 229 */
michael@0 230 int32_t charsCapacity;
michael@0 231
michael@0 232 /**
michael@0 233 * Default constructor for use with default implementations and subclasses.
michael@0 234 * @stable ICU 2.8
michael@0 235 */
michael@0 236 StringEnumeration();
michael@0 237
michael@0 238 /**
michael@0 239 * Ensures that chars is at least as large as the requested capacity.
michael@0 240 * For use with default implementations and subclasses.
michael@0 241 *
michael@0 242 * @param capacity Requested capacity.
michael@0 243 * @param status ICU in/out error code.
michael@0 244 * @stable ICU 2.8
michael@0 245 */
michael@0 246 void ensureCharsCapacity(int32_t capacity, UErrorCode &status);
michael@0 247
michael@0 248 /**
michael@0 249 * Converts s to Unicode and sets unistr to the result.
michael@0 250 * For use with default implementations and subclasses,
michael@0 251 * especially for implementations of snext() in terms of next().
michael@0 252 * This is provided with a helper function instead of a default implementation
michael@0 253 * of snext() to avoid potential infinite loops between next() and snext().
michael@0 254 *
michael@0 255 * For example:
michael@0 256 * \code
michael@0 257 * const UnicodeString* snext(UErrorCode& status) {
michael@0 258 * int32_t resultLength=0;
michael@0 259 * const char *s=next(&resultLength, status);
michael@0 260 * return setChars(s, resultLength, status);
michael@0 261 * }
michael@0 262 * \endcode
michael@0 263 *
michael@0 264 * @param s String to be converted to Unicode.
michael@0 265 * @param length Length of the string.
michael@0 266 * @param status ICU in/out error code.
michael@0 267 * @return A pointer to unistr.
michael@0 268 * @stable ICU 2.8
michael@0 269 */
michael@0 270 UnicodeString *setChars(const char *s, int32_t length, UErrorCode &status);
michael@0 271 };
michael@0 272
michael@0 273 U_NAMESPACE_END
michael@0 274
michael@0 275 /* STRENUM_H */
michael@0 276 #endif

mercurial