1/* 2 * Copyright (C) 2009, 2010, 2012, 2013 Apple Inc. All rights reserved. 3 * Copyright (C) 2012 Google Inc. All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 8 * 1. Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * 2. Redistributions in binary form must reproduce the above copyright 11 * notice, this list of conditions and the following disclaimer in the 12 * documentation and/or other materials provided with the distribution. 13 * 14 * THIS SOFTWARE IS PROVIDED BY APPLE INC. ``AS IS'' AND ANY 15 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 16 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 17 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR 18 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, 19 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, 20 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR 21 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY 22 * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 23 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE 24 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 25 */ 26 27#ifndef StringBuilder_h 28#define StringBuilder_h 29 30#include <wtf/text/AtomicString.h> 31#include <wtf/text/StringView.h> 32#include <wtf/text/WTFString.h> 33 34namespace WTF { 35 36class StringBuilder { 37 // Disallow copying since it's expensive and we don't want code to do it by accident. 38 WTF_MAKE_NONCOPYABLE(StringBuilder); 39 40public: 41 StringBuilder() 42 : m_length(0) 43 , m_is8Bit(true) 44 , m_bufferCharacters8(0) 45 { 46 } 47 48 WTF_EXPORT_PRIVATE void append(const UChar*, unsigned); 49 WTF_EXPORT_PRIVATE void append(const LChar*, unsigned); 50 51 ALWAYS_INLINE void append(const char* characters, unsigned length) { append(reinterpret_cast<const LChar*>(characters), length); } 52 53 void append(const String& string) 54 { 55 if (!string.length()) 56 return; 57 58 // If we're appending to an empty string, and there is not a buffer (reserveCapacity has not been called) 59 // then just retain the string. 60 if (!m_length && !m_buffer) { 61 m_string = string; 62 m_length = string.length(); 63 m_is8Bit = m_string.is8Bit(); 64 return; 65 } 66 67 if (string.is8Bit()) 68 append(string.characters8(), string.length()); 69 else 70 append(string.characters16(), string.length()); 71 } 72 73 void append(const StringBuilder& other) 74 { 75 if (!other.m_length) 76 return; 77 78 // If we're appending to an empty string, and there is not a buffer (reserveCapacity has not been called) 79 // then just retain the string. 80 if (!m_length && !m_buffer && !other.m_string.isNull()) { 81 m_string = other.m_string; 82 m_length = other.m_length; 83 return; 84 } 85 86 if (other.is8Bit()) 87 append(other.characters8(), other.m_length); 88 else 89 append(other.characters16(), other.m_length); 90 } 91 92 void append(StringView stringView) 93 { 94 if (stringView.is8Bit()) 95 append(stringView.characters8(), stringView.length()); 96 else 97 append(stringView.characters16(), stringView.length()); 98 } 99 100 void append(const String& string, unsigned offset, unsigned length) 101 { 102 if (!string.length()) 103 return; 104 105 if ((offset + length) > string.length()) 106 return; 107 108 if (string.is8Bit()) 109 append(string.characters8() + offset, length); 110 else 111 append(string.characters16() + offset, length); 112 } 113 114 void append(const char* characters) 115 { 116 if (characters) 117 append(characters, strlen(characters)); 118 } 119 120 void append(UChar c) 121 { 122 if (m_buffer && m_length < m_buffer->length() && m_string.isNull()) { 123 if (!m_is8Bit) { 124 m_bufferCharacters16[m_length++] = c; 125 return; 126 } 127 128 if (!(c & ~0xff)) { 129 m_bufferCharacters8[m_length++] = static_cast<LChar>(c); 130 return; 131 } 132 } 133 append(&c, 1); 134 } 135 136 void append(LChar c) 137 { 138 if (m_buffer && m_length < m_buffer->length() && m_string.isNull()) { 139 if (m_is8Bit) 140 m_bufferCharacters8[m_length++] = c; 141 else 142 m_bufferCharacters16[m_length++] = c; 143 } else 144 append(&c, 1); 145 } 146 147 void append(char c) 148 { 149 append(static_cast<LChar>(c)); 150 } 151 152 void append(UChar32 c) 153 { 154 if (U_IS_BMP(c)) { 155 append(static_cast<UChar>(c)); 156 return; 157 } 158 append(U16_LEAD(c)); 159 append(U16_TRAIL(c)); 160 } 161 162 template<unsigned charactersCount> 163 ALWAYS_INLINE void appendLiteral(const char (&characters)[charactersCount]) { append(characters, charactersCount - 1); } 164 165 WTF_EXPORT_PRIVATE void appendNumber(int); 166 WTF_EXPORT_PRIVATE void appendNumber(unsigned int); 167 WTF_EXPORT_PRIVATE void appendNumber(long); 168 WTF_EXPORT_PRIVATE void appendNumber(unsigned long); 169 WTF_EXPORT_PRIVATE void appendNumber(long long); 170 WTF_EXPORT_PRIVATE void appendNumber(unsigned long long); 171 WTF_EXPORT_PRIVATE void appendNumber(double, unsigned precision = 6, TrailingZerosTruncatingPolicy = TruncateTrailingZeros); 172 WTF_EXPORT_PRIVATE void appendECMAScriptNumber(double); 173 WTF_EXPORT_PRIVATE void appendFixedWidthNumber(double, unsigned decimalPlaces); 174 175 String toString() 176 { 177 shrinkToFit(); 178 if (m_string.isNull()) 179 reifyString(); 180 return m_string; 181 } 182 183 const String& toStringPreserveCapacity() const 184 { 185 if (m_string.isNull()) 186 reifyString(); 187 return m_string; 188 } 189 190 AtomicString toAtomicString() const 191 { 192 if (!m_length) 193 return emptyAtom; 194 195 // If the buffer is sufficiently over-allocated, make a new AtomicString from a copy so its buffer is not so large. 196 if (canShrink()) { 197 if (is8Bit()) 198 return AtomicString(characters8(), length()); 199 return AtomicString(characters16(), length()); 200 } 201 202 if (!m_string.isNull()) 203 return AtomicString(m_string); 204 205 ASSERT(m_buffer); 206 return AtomicString(m_buffer.get(), 0, m_length); 207 } 208 209 unsigned length() const 210 { 211 return m_length; 212 } 213 214 bool isEmpty() const { return !m_length; } 215 216 WTF_EXPORT_PRIVATE void reserveCapacity(unsigned newCapacity); 217 218 unsigned capacity() const 219 { 220 return m_buffer ? m_buffer->length() : m_length; 221 } 222 223 WTF_EXPORT_PRIVATE void resize(unsigned newSize); 224 225 WTF_EXPORT_PRIVATE bool canShrink() const; 226 227 WTF_EXPORT_PRIVATE void shrinkToFit(); 228 229 UChar operator[](unsigned i) const 230 { 231 ASSERT_WITH_SECURITY_IMPLICATION(i < m_length); 232 if (m_is8Bit) 233 return characters8()[i]; 234 return characters16()[i]; 235 } 236 237 const LChar* characters8() const 238 { 239 ASSERT(m_is8Bit); 240 if (!m_length) 241 return 0; 242 if (!m_string.isNull()) 243 return m_string.characters8(); 244 ASSERT(m_buffer); 245 return m_buffer->characters8(); 246 } 247 248 const UChar* characters16() const 249 { 250 ASSERT(!m_is8Bit); 251 if (!m_length) 252 return 0; 253 if (!m_string.isNull()) 254 return m_string.characters16(); 255 ASSERT(m_buffer); 256 return m_buffer->characters16(); 257 } 258 259 bool is8Bit() const { return m_is8Bit; } 260 261 void clear() 262 { 263 m_length = 0; 264 m_string = String(); 265 m_buffer = 0; 266 m_bufferCharacters8 = 0; 267 m_is8Bit = true; 268 } 269 270 void swap(StringBuilder& stringBuilder) 271 { 272 std::swap(m_length, stringBuilder.m_length); 273 m_string.swap(stringBuilder.m_string); 274 m_buffer.swap(stringBuilder.m_buffer); 275 std::swap(m_is8Bit, stringBuilder.m_is8Bit); 276 std::swap(m_bufferCharacters8, stringBuilder.m_bufferCharacters8); 277 } 278 279private: 280 void allocateBuffer(const LChar* currentCharacters, unsigned requiredLength); 281 void allocateBuffer(const UChar* currentCharacters, unsigned requiredLength); 282 void allocateBufferUpConvert(const LChar* currentCharacters, unsigned requiredLength); 283 template <typename CharType> 284 void reallocateBuffer(unsigned requiredLength); 285 template <typename CharType> 286 ALWAYS_INLINE CharType* appendUninitialized(unsigned length); 287 template <typename CharType> 288 CharType* appendUninitializedSlow(unsigned length); 289 template <typename CharType> 290 ALWAYS_INLINE CharType * getBufferCharacters(); 291 WTF_EXPORT_PRIVATE void reifyString() const; 292 293 unsigned m_length; 294 mutable String m_string; 295 RefPtr<StringImpl> m_buffer; 296 bool m_is8Bit; 297 union { 298 LChar* m_bufferCharacters8; 299 UChar* m_bufferCharacters16; 300 }; 301}; 302 303template <> 304ALWAYS_INLINE LChar* StringBuilder::getBufferCharacters<LChar>() 305{ 306 ASSERT(m_is8Bit); 307 return m_bufferCharacters8; 308} 309 310template <> 311ALWAYS_INLINE UChar* StringBuilder::getBufferCharacters<UChar>() 312{ 313 ASSERT(!m_is8Bit); 314 return m_bufferCharacters16; 315} 316 317template <typename CharType> 318bool equal(const StringBuilder& s, const CharType* buffer, unsigned length) 319{ 320 if (s.length() != length) 321 return false; 322 323 if (s.is8Bit()) 324 return equal(s.characters8(), buffer, length); 325 326 return equal(s.characters16(), buffer, length); 327} 328 329template <typename StringType> 330bool equal(const StringBuilder& a, const StringType& b) 331{ 332 if (a.length() != b.length()) 333 return false; 334 335 if (!a.length()) 336 return true; 337 338 if (a.is8Bit()) { 339 if (b.is8Bit()) 340 return equal(a.characters8(), b.characters8(), a.length()); 341 return equal(a.characters8(), b.characters16(), a.length()); 342 } 343 344 if (b.is8Bit()) 345 return equal(a.characters16(), b.characters8(), a.length()); 346 return equal(a.characters16(), b.characters16(), a.length()); 347} 348 349inline bool operator==(const StringBuilder& a, const StringBuilder& b) { return equal(a, b); } 350inline bool operator!=(const StringBuilder& a, const StringBuilder& b) { return !equal(a, b); } 351inline bool operator==(const StringBuilder& a, const String& b) { return equal(a, b); } 352inline bool operator!=(const StringBuilder& a, const String& b) { return !equal(a, b); } 353inline bool operator==(const String& a, const StringBuilder& b) { return equal(b, a); } 354inline bool operator!=(const String& a, const StringBuilder& b) { return !equal(b, a); } 355 356} // namespace WTF 357 358using WTF::StringBuilder; 359 360#endif // StringBuilder_h 361