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JSONTokener | 42 | 190 | 87 |
1 | package org.json; | |
2 | ||
3 | import java.io.BufferedReader; | |
4 | import java.io.IOException; | |
5 | import java.io.InputStream; | |
6 | import java.io.InputStreamReader; | |
7 | import java.io.Reader; | |
8 | import java.io.StringReader; | |
9 | ||
10 | /* | |
11 | Copyright (c) 2002 JSON.org | |
12 | ||
13 | Permission is hereby granted, free of charge, to any person obtaining a copy | |
14 | of this software and associated documentation files (the "Software"), to deal | |
15 | in the Software without restriction, including without limitation the rights | |
16 | to use, copy, modify, merge, publish, distribute, sublicense, and/or sell | |
17 | copies of the Software, and to permit persons to whom the Software is | |
18 | furnished to do so, subject to the following conditions: | |
19 | ||
20 | The above copyright notice and this permission notice shall be included in all | |
21 | copies or substantial portions of the Software. | |
22 | ||
23 | The Software shall be used for Good, not Evil. | |
24 | ||
25 | THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR | |
26 | IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, | |
27 | FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE | |
28 | AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER | |
29 | LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, | |
30 | OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE | |
31 | SOFTWARE. | |
32 | */ | |
33 | ||
34 | /** | |
35 | * A JSONTokener takes a source string and extracts characters and tokens from | |
36 | * it. It is used by the JSONObject and JSONArray constructors to parse JSON | |
37 | * source strings. | |
38 | * | |
39 | * @author JSON.org | |
40 | * @version 2014-05-03 | |
41 | */ | |
42 | public class JSONTokener | |
43 | { | |
44 | /** current read character position on the current line. */ | |
45 | private long character; | |
46 | ||
47 | /** flag to indicate if the end of the input has been found. */ | |
48 | private boolean eof; | |
49 | ||
50 | /** current read index of the input. */ | |
51 | private long index; | |
52 | ||
53 | /** current line of the input. */ | |
54 | private long line; | |
55 | ||
56 | /** previous character read from the input. */ | |
57 | private char previous; | |
58 | ||
59 | /** Reader for the input. */ | |
60 | private final Reader reader; | |
61 | ||
62 | /** flag to indicate that a previous character was requested. */ | |
63 | private boolean usePrevious; | |
64 | ||
65 | /** the number of characters read in the previous line. */ | |
66 | private long characterPreviousLine; | |
67 | ||
68 | /** | |
69 | * Construct a JSONTokener from a Reader. The caller must close the Reader. | |
70 | * | |
71 | * @param reader | |
72 | * A reader. | |
73 | */ | |
74 | 0 | public JSONTokener(Reader reader) |
75 | { | |
76 | 0 | this.reader = reader.markSupported() ? reader |
77 | : new BufferedReader(reader); | |
78 | 0 | this.eof = false; |
79 | 0 | this.usePrevious = false; |
80 | 0 | this.previous = 0; |
81 | 0 | this.index = 0; |
82 | 0 | this.character = 1; |
83 | 0 | this.characterPreviousLine = 0; |
84 | 0 | this.line = 1; |
85 | } | |
86 | ||
87 | /** | |
88 | * Construct a JSONTokener from an InputStream. The caller must close the | |
89 | * input stream. | |
90 | * | |
91 | * @param inputStream | |
92 | * The source. | |
93 | */ | |
94 | 0 | public JSONTokener(InputStream inputStream) |
95 | { | |
96 | 0 | this(new InputStreamReader(inputStream)); |
97 | } | |
98 | ||
99 | /** | |
100 | * Construct a JSONTokener from a string. | |
101 | * | |
102 | * @param s | |
103 | * A source string. | |
104 | */ | |
105 | 0 | public JSONTokener(String s) |
106 | { | |
107 | 0 | this(new StringReader(s)); |
108 | } | |
109 | ||
110 | /** | |
111 | * Back up one character. This provides a sort of lookahead capability, so | |
112 | * that you can test for a digit or letter before attempting to parse the next | |
113 | * number or identifier. | |
114 | * | |
115 | * @throws JSONException | |
116 | * Thrown if trying to step back more than 1 step or if already at | |
117 | * the start of the string | |
118 | */ | |
119 | 0 | public void back() throws JSONException |
120 | { | |
121 | 0 | if (this.usePrevious || this.index <= 0) |
122 | { | |
123 | 0 | throw new JSONException("Stepping back two steps is not supported"); |
124 | } | |
125 | 0 | this.decrementIndexes(); |
126 | 0 | this.usePrevious = true; |
127 | 0 | this.eof = false; |
128 | } | |
129 | ||
130 | /** | |
131 | * Decrements the indexes for the {@link #back()} method based on the previous | |
132 | * character read. | |
133 | */ | |
134 | 0 | private void decrementIndexes() |
135 | { | |
136 | 0 | this.index--; |
137 | 0 | if (this.previous == '\r' || this.previous == '\n') |
138 | { | |
139 | 0 | this.line--; |
140 | 0 | this.character = this.characterPreviousLine; |
141 | } | |
142 | 0 | else if (this.character > 0) |
143 | { | |
144 | 0 | this.character--; |
145 | } | |
146 | } | |
147 | ||
148 | /** | |
149 | * Get the hex value of a character (base16). | |
150 | * | |
151 | * @param c | |
152 | * A character between '0' and '9' or between 'A' and 'F' or between | |
153 | * 'a' and 'f'. | |
154 | * @return An int between 0 and 15, or -1 if c was not a hex digit. | |
155 | */ | |
156 | 0 | public static int dehexchar(char c) |
157 | { | |
158 | 0 | if (c >= '0' && c <= '9') |
159 | { | |
160 | 0 | return c - '0'; |
161 | } | |
162 | 0 | if (c >= 'A' && c <= 'F') |
163 | { | |
164 | 0 | return c - ('A' - 10); |
165 | } | |
166 | 0 | if (c >= 'a' && c <= 'f') |
167 | { | |
168 | 0 | return c - ('a' - 10); |
169 | } | |
170 | 0 | return -1; |
171 | } | |
172 | ||
173 | /** | |
174 | * Checks if the end of the input has been reached. | |
175 | * | |
176 | * @return true if at the end of the file and we didn't step back | |
177 | */ | |
178 | 0 | public boolean end() |
179 | { | |
180 | 0 | return this.eof && !this.usePrevious; |
181 | } | |
182 | ||
183 | /** | |
184 | * Determine if the source string still contains characters that next() can | |
185 | * consume. | |
186 | * | |
187 | * @return true if not yet at the end of the source. | |
188 | * @throws JSONException | |
189 | * thrown if there is an error stepping forward or backward while | |
190 | * checking for more data. | |
191 | */ | |
192 | 0 | public boolean more() throws JSONException |
193 | { | |
194 | 0 | if (this.usePrevious) |
195 | { | |
196 | 0 | return true; |
197 | } | |
198 | 0 | try |
199 | { | |
200 | 0 | this.reader.mark(1); |
201 | } catch (IOException e) | |
202 | { | |
203 | 0 | throw new JSONException("Unable to preserve stream position", e); |
204 | } | |
205 | 0 | try |
206 | { | |
207 | // -1 is EOF, but next() can not consume the null character '\0' | |
208 | 0 | if (this.reader.read() <= 0) |
209 | { | |
210 | 0 | this.eof = true; |
211 | 0 | return false; |
212 | } | |
213 | 0 | this.reader.reset(); |
214 | } catch (IOException e) | |
215 | { | |
216 | 0 | throw new JSONException( |
217 | "Unable to read the next character from the stream", e); | |
218 | } | |
219 | 0 | return true; |
220 | } | |
221 | ||
222 | /** | |
223 | * Get the next character in the source string. | |
224 | * | |
225 | * @return The next character, or 0 if past the end of the source string. | |
226 | * @throws JSONException | |
227 | * Thrown if there is an error reading the source string. | |
228 | */ | |
229 | 0 | public char next() throws JSONException |
230 | { | |
231 | 0 | int c; |
232 | 0 | if (this.usePrevious) |
233 | { | |
234 | 0 | this.usePrevious = false; |
235 | 0 | c = this.previous; |
236 | } | |
237 | else | |
238 | { | |
239 | 0 | try |
240 | { | |
241 | 0 | c = this.reader.read(); |
242 | } catch (IOException exception) | |
243 | { | |
244 | 0 | throw new JSONException(exception); |
245 | } | |
246 | } | |
247 | 0 | if (c <= 0) |
248 | { // End of stream | |
249 | 0 | this.eof = true; |
250 | 0 | return 0; |
251 | } | |
252 | 0 | this.incrementIndexes(c); |
253 | 0 | this.previous = (char) c; |
254 | 0 | return this.previous; |
255 | } | |
256 | ||
257 | /** | |
258 | * Increments the internal indexes according to the previous character read | |
259 | * and the character passed as the current character. | |
260 | * | |
261 | * @param c | |
262 | * the current character read. | |
263 | */ | |
264 | 0 | private void incrementIndexes(int c) |
265 | { | |
266 | 0 | if (c > 0) |
267 | { | |
268 | 0 | this.index++; |
269 | 0 | if (c == '\r') |
270 | { | |
271 | 0 | this.line++; |
272 | 0 | this.characterPreviousLine = this.character; |
273 | 0 | this.character = 0; |
274 | } | |
275 | 0 | else if (c == '\n') |
276 | { | |
277 | 0 | if (this.previous != '\r') |
278 | { | |
279 | 0 | this.line++; |
280 | 0 | this.characterPreviousLine = this.character; |
281 | } | |
282 | 0 | this.character = 0; |
283 | } | |
284 | else | |
285 | { | |
286 | 0 | this.character++; |
287 | } | |
288 | } | |
289 | } | |
290 | ||
291 | /** | |
292 | * Consume the next character, and check that it matches a specified | |
293 | * character. | |
294 | * | |
295 | * @param c | |
296 | * The character to match. | |
297 | * @return The character. | |
298 | * @throws JSONException | |
299 | * if the character does not match. | |
300 | */ | |
301 | 0 | public char next(char c) throws JSONException |
302 | { | |
303 | 0 | char n = this.next(); |
304 | 0 | if (n != c) |
305 | { | |
306 | 0 | if (n > 0) |
307 | { | |
308 | 0 | throw this.syntaxError( |
309 | "Expected '" + c + "' and instead saw '" + n + "'"); | |
310 | } | |
311 | 0 | throw this.syntaxError("Expected '" + c + "' and instead saw ''"); |
312 | } | |
313 | 0 | return n; |
314 | } | |
315 | ||
316 | /** | |
317 | * Get the next n characters. | |
318 | * | |
319 | * @param n | |
320 | * The number of characters to take. | |
321 | * @return A string of n characters. | |
322 | * @throws JSONException | |
323 | * Substring bounds error if there are not n characters remaining in | |
324 | * the source string. | |
325 | */ | |
326 | 0 | public String next(int n) throws JSONException |
327 | { | |
328 | 0 | if (n == 0) |
329 | { | |
330 | 0 | return ""; |
331 | } | |
332 | ||
333 | 0 | char[] chars = new char[n]; |
334 | 0 | int pos = 0; |
335 | ||
336 | 0 | while (pos < n) |
337 | { | |
338 | 0 | chars[pos] = this.next(); |
339 | 0 | if (this.end()) |
340 | { | |
341 | 0 | throw this.syntaxError("Substring bounds error"); |
342 | } | |
343 | 0 | pos += 1; |
344 | } | |
345 | 0 | return new String(chars); |
346 | } | |
347 | ||
348 | /** | |
349 | * Get the next char in the string, skipping whitespace. | |
350 | * | |
351 | * @throws JSONException | |
352 | * Thrown if there is an error reading the source string. | |
353 | * @return A character, or 0 if there are no more characters. | |
354 | */ | |
355 | 0 | public char nextClean() throws JSONException |
356 | { | |
357 | 0 | for (;;) |
358 | { | |
359 | 0 | char c = this.next(); |
360 | 0 | if (c == 0 || c > ' ') |
361 | { | |
362 | 0 | return c; |
363 | } | |
364 | } | |
365 | } | |
366 | ||
367 | /** | |
368 | * Return the characters up to the next close quote character. Backslash | |
369 | * processing is done. The formal JSON format does not allow strings in single | |
370 | * quotes, but an implementation is allowed to accept them. | |
371 | * | |
372 | * @param quote | |
373 | * The quoting character, either <code>"</code> <small>(double | |
374 | * quote)</small> or <code>'</code> <small>(single | |
375 | * quote)</small>. | |
376 | * @return A String. | |
377 | * @throws JSONException | |
378 | * Unterminated string. | |
379 | */ | |
380 | 0 | public String nextString(char quote) throws JSONException |
381 | { | |
382 | 0 | char c; |
383 | 0 | StringBuilder sb = new StringBuilder(); |
384 | 0 | for (;;) |
385 | { | |
386 | 0 | c = this.next(); |
387 | 0 | switch (c) |
388 | { | |
389 | 0 | case 0: |
390 | 0 | case '\n': |
391 | 0 | case '\r': |
392 | 0 | throw this.syntaxError("Unterminated string"); |
393 | 0 | case '\\': |
394 | 0 | c = this.next(); |
395 | 0 | switch (c) |
396 | { | |
397 | 0 | case 'b': |
398 | 0 | sb.append('\b'); |
399 | 0 | break; |
400 | 0 | case 't': |
401 | 0 | sb.append('\t'); |
402 | 0 | break; |
403 | 0 | case 'n': |
404 | 0 | sb.append('\n'); |
405 | 0 | break; |
406 | 0 | case 'f': |
407 | 0 | sb.append('\f'); |
408 | 0 | break; |
409 | 0 | case 'r': |
410 | 0 | sb.append('\r'); |
411 | 0 | break; |
412 | 0 | case 'u': |
413 | 0 | try |
414 | { | |
415 | 0 | sb.append((char) Integer.parseInt(this.next(4), 16)); |
416 | } catch (NumberFormatException e) | |
417 | { | |
418 | 0 | throw this.syntaxError("Illegal escape.", e); |
419 | } | |
420 | 0 | break; |
421 | 0 | case '"': |
422 | 0 | case '\'': |
423 | 0 | case '\\': |
424 | 0 | case '/': |
425 | 0 | sb.append(c); |
426 | 0 | break; |
427 | 0 | default: |
428 | 0 | throw this.syntaxError("Illegal escape."); |
429 | } | |
430 | 0 | break; |
431 | 0 | default: |
432 | 0 | if (c == quote) |
433 | { | |
434 | 0 | return sb.toString(); |
435 | } | |
436 | 0 | sb.append(c); |
437 | } | |
438 | } | |
439 | } | |
440 | ||
441 | /** | |
442 | * Get the text up but not including the specified character or the end of | |
443 | * line, whichever comes first. | |
444 | * | |
445 | * @param delimiter | |
446 | * A delimiter character. | |
447 | * @return A string. | |
448 | * @throws JSONException | |
449 | * Thrown if there is an error while searching for the delimiter | |
450 | */ | |
451 | 0 | public String nextTo(char delimiter) throws JSONException |
452 | { | |
453 | 0 | StringBuilder sb = new StringBuilder(); |
454 | 0 | for (;;) |
455 | { | |
456 | 0 | char c = this.next(); |
457 | 0 | if (c == delimiter || c == 0 || c == '\n' || c == '\r') |
458 | { | |
459 | 0 | if (c != 0) |
460 | { | |
461 | 0 | this.back(); |
462 | } | |
463 | 0 | return sb.toString().trim(); |
464 | } | |
465 | 0 | sb.append(c); |
466 | } | |
467 | } | |
468 | ||
469 | /** | |
470 | * Get the text up but not including one of the specified delimiter characters | |
471 | * or the end of line, whichever comes first. | |
472 | * | |
473 | * @param delimiters | |
474 | * A set of delimiter characters. | |
475 | * @return A string, trimmed. | |
476 | * @throws JSONException | |
477 | * Thrown if there is an error while searching for the delimiter | |
478 | */ | |
479 | 0 | public String nextTo(String delimiters) throws JSONException |
480 | { | |
481 | 0 | char c; |
482 | 0 | StringBuilder sb = new StringBuilder(); |
483 | 0 | for (;;) |
484 | { | |
485 | 0 | c = this.next(); |
486 | 0 | if (delimiters.indexOf(c) >= 0 || c == 0 || c == '\n' || c == '\r') |
487 | { | |
488 | 0 | if (c != 0) |
489 | { | |
490 | 0 | this.back(); |
491 | } | |
492 | 0 | return sb.toString().trim(); |
493 | } | |
494 | 0 | sb.append(c); |
495 | } | |
496 | } | |
497 | ||
498 | /** | |
499 | * Get the next value. The value can be a Boolean, Double, Integer, JSONArray, | |
500 | * JSONObject, Long, or String, or the JSONObject.NULL object. | |
501 | * | |
502 | * @throws JSONException | |
503 | * If syntax error. | |
504 | * | |
505 | * @return An object. | |
506 | */ | |
507 | 0 | public Object nextValue() throws JSONException |
508 | { | |
509 | 0 | char c = this.nextClean(); |
510 | 0 | String string; |
511 | ||
512 | 0 | switch (c) |
513 | { | |
514 | 0 | case '"': |
515 | 0 | case '\'': |
516 | 0 | return this.nextString(c); |
517 | 0 | case '{': |
518 | 0 | this.back(); |
519 | 0 | return new JSONObject(this); |
520 | 0 | case '[': |
521 | 0 | this.back(); |
522 | 0 | return new JSONArray(this); |
523 | } | |
524 | ||
525 | /* | |
526 | * Handle unquoted text. This could be the values true, false, or | |
527 | * null, or it can be a number. An implementation (such as this one) | |
528 | * is allowed to also accept non-standard forms. | |
529 | * | |
530 | * Accumulate characters until we reach the end of the text or a | |
531 | * formatting character. | |
532 | */ | |
533 | ||
534 | 0 | StringBuilder sb = new StringBuilder(); |
535 | 0 | while (c >= ' ' && ",:]}/\\\"[{;=#".indexOf(c) < 0) |
536 | { | |
537 | 0 | sb.append(c); |
538 | 0 | c = this.next(); |
539 | } | |
540 | 0 | this.back(); |
541 | ||
542 | 0 | string = sb.toString().trim(); |
543 | 0 | if ("".equals(string)) |
544 | { | |
545 | 0 | throw this.syntaxError("Missing value"); |
546 | } | |
547 | 0 | return JSONObject.stringToValue(string); |
548 | } | |
549 | ||
550 | /** | |
551 | * Skip characters until the next character is the requested character. If the | |
552 | * requested character is not found, no characters are skipped. | |
553 | * | |
554 | * @param to | |
555 | * A character to skip to. | |
556 | * @return The requested character, or zero if the requested character is not | |
557 | * found. | |
558 | * @throws JSONException | |
559 | * Thrown if there is an error while searching for the to character | |
560 | */ | |
561 | 0 | public char skipTo(char to) throws JSONException |
562 | { | |
563 | 0 | char c; |
564 | 0 | try |
565 | { | |
566 | 0 | long startIndex = this.index; |
567 | 0 | long startCharacter = this.character; |
568 | 0 | long startLine = this.line; |
569 | 0 | this.reader.mark(1000000); |
570 | 0 | do |
571 | { | |
572 | 0 | c = this.next(); |
573 | 0 | if (c == 0) |
574 | { | |
575 | // in some readers, reset() may throw an exception if | |
576 | // the remaining portion of the input is greater than | |
577 | // the mark size (1,000,000 above). | |
578 | 0 | this.reader.reset(); |
579 | 0 | this.index = startIndex; |
580 | 0 | this.character = startCharacter; |
581 | 0 | this.line = startLine; |
582 | 0 | return 0; |
583 | } | |
584 | 0 | } while (c != to); |
585 | 0 | this.reader.mark(1); |
586 | } catch (IOException exception) | |
587 | { | |
588 | 0 | throw new JSONException(exception); |
589 | } | |
590 | 0 | this.back(); |
591 | 0 | return c; |
592 | } | |
593 | ||
594 | /** | |
595 | * Make a JSONException to signal a syntax error. | |
596 | * | |
597 | * @param message | |
598 | * The error message. | |
599 | * @return A JSONException object, suitable for throwing | |
600 | */ | |
601 | 0 | public JSONException syntaxError(String message) |
602 | { | |
603 | 0 | return new JSONException(message + this.toString()); |
604 | } | |
605 | ||
606 | /** | |
607 | * Make a JSONException to signal a syntax error. | |
608 | * | |
609 | * @param message | |
610 | * The error message. | |
611 | * @param causedBy | |
612 | * The throwable that caused the error. | |
613 | * @return A JSONException object, suitable for throwing | |
614 | */ | |
615 | 0 | public JSONException syntaxError(String message, Throwable causedBy) |
616 | { | |
617 | 0 | return new JSONException(message + this.toString(), causedBy); |
618 | } | |
619 | ||
620 | /** | |
621 | * Make a printable string of this JSONTokener. | |
622 | * | |
623 | * @return " at {index} [character {character} line {line}]" | |
624 | */ | |
625 | 0 | @Override |
626 | public String toString() | |
627 | { | |
628 | 0 | return " at " + this.index + " [character " + this.character + " line " |
629 | + this.line + "]"; | |
630 | } | |
631 | } |