JSON-java/Kim.java at master · salyh/JSON-java · GitHub

History

372 lines (344 loc) · 12.5 KB

Raw

100

101

102

103

104

105

106

107

108

109

110

111

112

113

114

115

116

117

118

119

120

121

122

123

124

125

126

127

128

129

130

131

132

133

134

135

136

137

138

139

140

141

142

143

144

145

146

147

148

149

150

151

152

153

154

155

156

157

158

159

160

161

162

163

164

165

166

167

168

169

170

171

172

173

174

175

176

177

178

179

180

181

182

183

184

185

186

187

188

189

190

191

192

193

194

195

196

197

198

199

200

201

202

203

204

205

206

207

208

209

210

211

212

213

214

215

216

217

218

219

220

221

222

223

224

225

226

227

228

229

230

231

232

233

234

235

236

237

238

239

240

241

242

243

244

245

246

247

248

249

250

251

252

253

254

255

256

257

258

259

260

261

262

263

264

265

266

267

268

269

270

271

272

273

274

275

276

277

278

279

280

281

282

283

284

285

286

287

288

289

290

291

292

293

294

295

296

297

298

299

300

301

302

303

304

305

306

307

308

309

310

311

312

313

314

315

316

317

318

319

320

321

322

323

324

325

326

327

328

329

330

331

332

333

334

335

336

337

338

339

340

341

342

343

344

345

346

347

348

349

350

351

352

353

354

355

356

357

358

359

360

361

362

363

364

365

366

367

368

369

370

371

372

package org.json;

Permission is hereby granted, free of charge, to any person obtaining a copy

of this software and associated documentation files (the "Software"), to deal

in the Software without restriction, including without limitation the rights

to use, copy, modify, merge, publish, distribute, sublicense, and/or sell

copies of the Software, and to permit persons to whom the Software is

furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all

copies or substantial portions of the Software.

The Software shall be used for Good, not Evil.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR

IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,

FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE

AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER

LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,

OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE

SOFTWARE.

/**

* Kim makes immutable eight bit Unicode strings. If the MSB of a byte is set,

* then the next byte is a continuation byte. The last byte of a character

* never has the MSB reset. Every byte that is not the last byte has the MSB

* set. Kim stands for "Keep it minimal". A Unicode character is never longer

* than 3 bytes. Every byte contributes 7 bits to the character. ASCII is

* unmodified.

* Kim UTF-8

* one byte U+007F U+007F

* two bytes U+3FFF U+07FF

* three bytes U+10FFF U+FFFF

* four bytes U+10FFFF

* Characters in the ranges U+0800..U+3FFF and U+10000..U+10FFFF will be one

* byte smaller when encoded in Kim compared to UTF-8.

* Kim is beneficial when using scripts such as Old South Arabian, Aramaic,

* Avestan, Balinese, Batak, Bopomofo, Buginese, Buhid, Carian, Cherokee,

* Coptic, Cyrillic, Deseret, Egyptian Hieroglyphs, Ethiopic, Georgian,

* Glagolitic, Gothic, Hangul Jamo, Hanunoo, Hiragana, Kanbun, Kaithi,

* Kannada, Katakana, Kharoshthi, Khmer, Lao, Lepcha, Limbu, Lycian, Lydian,

* Malayalam, Mandaic, Meroitic, Miao, Mongolian, Myanmar, New Tai Lue,

* Ol Chiki, Old Turkic, Oriya, Osmanya, Pahlavi, Parthian, Phags-Pa,

* Phoenician, Samaritan, Sharada, Sinhala, Sora Sompeng, Tagalog, Tagbanwa,

* Takri, Tai Le, Tai Tham, Tamil, Telugu, Thai, Tibetan, Tifinagh, UCAS.

* A kim object can be constructed from an ordinary UTF-16 string, or from a

* byte array. A kim object can produce a UTF-16 string.

* As with UTF-8, it is possible to detect character boundaries within a byte

* sequence. UTF-8 is one of the world's great inventions. While Kim is more

* efficient, it is not clear that it is worth the expense of transition.

* @version 2013-04-18

public class Kim {

/**

* The byte array containing the kim's content.

private byte[] bytes = null;

/**

* The kim's hashcode, conforming to Java's hashcode conventions.

private int hashcode = 0;

/**

* The number of bytes in the kim. The number of bytes can be as much as

* three times the number of characters.

public int length = 0;

/**

* The memoization of toString().

private String string = null;

/**

* Make a kim from a portion of a byte array.

* @param bytes

* A byte array.

* @param from

* The index of the first byte.

* @param thru

* The index of the last byte plus one.

public Kim(byte[] bytes, int from, int thru) {

// As the bytes are copied into the new kim, a hashcode is computed using a

// modified Fletcher code.

int sum = 1;

int value;

this.hashcode = 0;

this.length = thru - from;

if (this.length > 0) {

this.bytes = new byte[this.length];

for (int at = 0; at < this.length; at += 1) {

value = (int) bytes[at + from] & 0xFF;

sum += value;

this.hashcode += sum;

this.bytes[at] = (byte) value;

}

this.hashcode += sum << 16;

}

/**

* Make a kim from a byte array.

* @param bytes

* The byte array.

* @param length

* The number of bytes.

public Kim(byte[] bytes, int length) {

this(bytes, 0, length);

}

/**

* Make a new kim from a substring of an existing kim. The coordinates are

* in byte units, not character units.

* @param kim

* The source of bytes.

* @param from

* The point at which to take bytes.

* @param thru

* The point at which to stop taking bytes.

public Kim(Kim kim, int from, int thru) {

this(kim.bytes, from, thru);

}

/**

* Make a kim from a string.

* @param string

* The string.

* @throws JSONException

* if surrogate pair mismatch.

public Kim(String string) throws JSONException {

int stringLength = string.length();

this.hashcode = 0;

this.length = 0;

// First pass: Determine the length of the kim, allowing for the UTF-16

// to UTF-32 conversion, and then the UTF-32 to Kim conversion.

if (stringLength > 0) {

for (int i = 0; i < stringLength; i += 1) {

int c = string.charAt(i);

if (c <= 0x7F) {

this.length += 1;

} else if (c <= 0x3FFF) {

this.length += 2;

} else {

if (c >= 0xD800 && c <= 0xDFFF) {

i += 1;

int d = string.charAt(i);

if (c > 0xDBFF || d < 0xDC00 || d > 0xDFFF) {

throw new JSONException("Bad UTF16");

}

this.length += 3;

}

// Second pass: Allocate a byte array and fill that array with the conversion

// while computing the hashcode.

this.bytes = new byte[length];

int at = 0;

int b;

int sum = 1;

for (int i = 0; i < stringLength; i += 1) {

int character = string.charAt(i);

if (character <= 0x7F) {

bytes[at] = (byte) character;

sum += character;

this.hashcode += sum;

at += 1;

} else if (character <= 0x3FFF) {

b = 0x80 | (character >>> 7);

bytes[at] = (byte) b;

sum += b;

this.hashcode += sum;

at += 1;

b = character & 0x7F;

bytes[at] = (byte) b;

sum += b;

this.hashcode += sum;

at += 1;

} else {

if (character >= 0xD800 && character <= 0xDBFF) {

i += 1;

character = (((character & 0x3FF) << 10) | (string

.charAt(i) & 0x3FF)) + 65536;

}

b = 0x80 | (character >>> 14);

bytes[at] = (byte) b;

sum += b;

this.hashcode += sum;

at += 1;

b = 0x80 | ((character >>> 7) & 0xFF);

bytes[at] = (byte) b;

sum += b;

this.hashcode += sum;

at += 1;

b = character & 0x7F;

bytes[at] = (byte) b;

sum += b;

this.hashcode += sum;

at += 1;

}

this.hashcode += sum << 16;

}

/**

* Returns the character at the specified index. The index refers to byte

* values and ranges from 0 to length - 1. The index of the next character

* is at index + Kim.characterSize(kim.characterAt(index)).

* @param at

* the index of the char value. The first character is at 0.

* @returns a Unicode character between 0 and 0x10FFFF.

* @throws JSONException

* if at does not point to a valid character.

public int characterAt(int at) throws JSONException {

int c = get(at);

if ((c & 0x80) == 0) {

return c;

}

int character;

int c1 = get(at + 1);

if ((c1 & 0x80) == 0) {

character = ((c & 0x7F) << 7) | c1;

if (character > 0x7F) {

return character;

}

} else {

int c2 = get(at + 2);

character = ((c & 0x7F) << 14) | ((c1 & 0x7F) << 7) | c2;

if ((c2 & 0x80) == 0 && character > 0x3FFF && character <= 0x10FFFF

&& (character < 0xD800 || character > 0xDFFF)) {

return character;

}

throw new JSONException("Bad character at " + at);

}

/**

* Returns the number of bytes needed to contain the character in Kim

* format.

* @param character

* a Unicode character between 0 and 0x10FFFF.

* @return 1, 2, or 3

* @throws JSONException

* if the character is not representable in a kim.

public static int characterSize(int character) throws JSONException {

if (character < 0 || character > 0x10FFFF) {

throw new JSONException("Bad character " + character);

}

return character <= 0x7F ? 1 : character <= 0x3FFF ? 2 : 3;

}

/**

* Copy the contents of this kim to a byte array.

* @param bytes

* A byte array of sufficient size.

* @param at

* The position within the byte array to take the byes.

* @return The position immediately after the copy.

public int copy(byte[] bytes, int at) {

System.arraycopy(this.bytes, 0, bytes, at, this.length);

return at + this.length;

}

/**

* Two kim objects containing exactly the same bytes in the same order are

* equal to each other.

* @param obj

* the other kim with which to compare.

* @returns true if this and obj are both kim objects containing identical

* byte sequences.

public boolean equals(Object obj) {

if (!(obj instanceof Kim)) {

return false;

}

Kim that = (Kim) obj;

if (this == that) {

return true;

}

if (this.hashcode != that.hashcode) {

return false;

}

return java.util.Arrays.equals(this.bytes, that.bytes);

}

/**

* Get a byte from a kim.

* @param at

* The position of the byte. The first byte is at 0.

* @return The byte.

* @throws JSONException

* if there is no byte at that position.

public int get(int at) throws JSONException {

if (at < 0 || at > this.length) {

throw new JSONException("Bad character at " + at);

}

return ((int) this.bytes[at]) & 0xFF;

}

/**

* Returns a hash code value for the kim.

public int hashCode() {

return this.hashcode;

}

/**

* Produce a UTF-16 String from this kim. The number of codepoints in the

* string will not be greater than the number of bytes in the kim, although

* it could be less.

* @return The string. A kim memoizes its string representation.

* @throws JSONException

* if the kim is not valid.

public String toString() throws JSONException {

if (this.string == null) {

int c;

int length = 0;

char chars[] = new char[this.length];

for (int at = 0; at < this.length; at += characterSize(c)) {

c = this.characterAt(at);

if (c < 0x10000) {

chars[length] = (char) c;

length += 1;

} else {

chars[length] = (char) (0xD800 | ((c - 0x10000) >>> 10));

length += 1;

chars[length] = (char) (0xDC00 | (c & 0x03FF));

length += 1;

}

this.string = new String(chars, 0, length);

}

return this.string;

}

JSON-java/Kim.java at master · salyh/JSON-java · GitHub

Expand file tree

Breadcrumbs

Kim.java

Latest commit

History

Breadcrumbs

Kim.java

File metadata and controls