1 /*
2 * Copyright (c) 2010 Serge A. Zaitsev
3 *
4 * Permission is hereby granted, free of charge, to any person obtaining a copy
5 * of this software and associated documentation files (the "Software"), to deal
6 * in the Software without restriction, including without limitation the rights
7 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
8 * copies of the Software, and to permit persons to whom the Software is
9 * furnished to do so, subject to the following conditions:
10 *
11 * The above copyright notice and this permission notice shall be included in
12 * all copies or substantial portions of the Software.
13 *
14 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
15 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
16 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
17 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
18 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
19 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
20 * THE SOFTWARE.
21 *
22 * Slightly modified by AK to not assume 0 terminated input.
23 *
24 */
25
26 #include <stdlib.h>
27 #include "jsmn.h"
28 #define JSMN_STRICT
29
30 /*
31 * Allocates a fresh unused token from the token pool.
32 */
jsmn_alloc_token(jsmn_parser * parser,jsmntok_t * tokens,size_t num_tokens)33 static jsmntok_t *jsmn_alloc_token(jsmn_parser *parser,
34 jsmntok_t *tokens, size_t num_tokens)
35 {
36 jsmntok_t *tok;
37
38 if ((unsigned)parser->toknext >= num_tokens)
39 return NULL;
40 tok = &tokens[parser->toknext++];
41 tok->start = tok->end = -1;
42 tok->size = 0;
43 return tok;
44 }
45
46 /*
47 * Fills token type and boundaries.
48 */
jsmn_fill_token(jsmntok_t * token,jsmntype_t type,int start,int end)49 static void jsmn_fill_token(jsmntok_t *token, jsmntype_t type,
50 int start, int end)
51 {
52 token->type = type;
53 token->start = start;
54 token->end = end;
55 token->size = 0;
56 }
57
58 /*
59 * Fills next available token with JSON primitive.
60 */
jsmn_parse_primitive(jsmn_parser * parser,const char * js,size_t len,jsmntok_t * tokens,size_t num_tokens)61 static jsmnerr_t jsmn_parse_primitive(jsmn_parser *parser, const char *js,
62 size_t len,
63 jsmntok_t *tokens, size_t num_tokens)
64 {
65 jsmntok_t *token;
66 int start;
67
68 start = parser->pos;
69
70 for (; parser->pos < len; parser->pos++) {
71 switch (js[parser->pos]) {
72 #ifndef JSMN_STRICT
73 /*
74 * In strict mode primitive must be followed by ","
75 * or "}" or "]"
76 */
77 case ':':
78 #endif
79 case '\t':
80 case '\r':
81 case '\n':
82 case ' ':
83 case ',':
84 case ']':
85 case '}':
86 goto found;
87 default:
88 break;
89 }
90 if (js[parser->pos] < 32 || js[parser->pos] >= 127) {
91 parser->pos = start;
92 return JSMN_ERROR_INVAL;
93 }
94 }
95 #ifdef JSMN_STRICT
96 /*
97 * In strict mode primitive must be followed by a
98 * comma/object/array.
99 */
100 parser->pos = start;
101 return JSMN_ERROR_PART;
102 #endif
103
104 found:
105 token = jsmn_alloc_token(parser, tokens, num_tokens);
106 if (token == NULL) {
107 parser->pos = start;
108 return JSMN_ERROR_NOMEM;
109 }
110 jsmn_fill_token(token, JSMN_PRIMITIVE, start, parser->pos);
111 parser->pos--; /* parent sees closing brackets */
112 return JSMN_SUCCESS;
113 }
114
115 /*
116 * Fills next token with JSON string.
117 */
jsmn_parse_string(jsmn_parser * parser,const char * js,size_t len,jsmntok_t * tokens,size_t num_tokens)118 static jsmnerr_t jsmn_parse_string(jsmn_parser *parser, const char *js,
119 size_t len,
120 jsmntok_t *tokens, size_t num_tokens)
121 {
122 jsmntok_t *token;
123 int start = parser->pos;
124
125 /* Skip starting quote */
126 parser->pos++;
127
128 for (; parser->pos < len; parser->pos++) {
129 char c = js[parser->pos];
130
131 /* Quote: end of string */
132 if (c == '\"') {
133 token = jsmn_alloc_token(parser, tokens, num_tokens);
134 if (token == NULL) {
135 parser->pos = start;
136 return JSMN_ERROR_NOMEM;
137 }
138 jsmn_fill_token(token, JSMN_STRING, start+1,
139 parser->pos);
140 return JSMN_SUCCESS;
141 }
142
143 /* Backslash: Quoted symbol expected */
144 if (c == '\\') {
145 parser->pos++;
146 switch (js[parser->pos]) {
147 /* Allowed escaped symbols */
148 case '\"':
149 case '/':
150 case '\\':
151 case 'b':
152 case 'f':
153 case 'r':
154 case 'n':
155 case 't':
156 break;
157 /* Allows escaped symbol \uXXXX */
158 case 'u':
159 /* TODO */
160 break;
161 /* Unexpected symbol */
162 default:
163 parser->pos = start;
164 return JSMN_ERROR_INVAL;
165 }
166 }
167 }
168 parser->pos = start;
169 return JSMN_ERROR_PART;
170 }
171
172 /*
173 * Parse JSON string and fill tokens.
174 */
jsmn_parse(jsmn_parser * parser,const char * js,size_t len,jsmntok_t * tokens,unsigned int num_tokens)175 jsmnerr_t jsmn_parse(jsmn_parser *parser, const char *js, size_t len,
176 jsmntok_t *tokens, unsigned int num_tokens)
177 {
178 jsmnerr_t r;
179 int i;
180 jsmntok_t *token;
181 #ifdef JSMN_STRICT
182 /*
183 * Keeps track of whether a new object/list/primitive is expected. New items are only
184 * allowed after an opening brace, comma or colon. A closing brace after a comma is not
185 * valid JSON.
186 */
187 int expecting_item = 1;
188 #endif
189
190 for (; parser->pos < len; parser->pos++) {
191 char c;
192 jsmntype_t type;
193
194 c = js[parser->pos];
195 switch (c) {
196 case '{':
197 case '[':
198 #ifdef JSMN_STRICT
199 if (!expecting_item)
200 return JSMN_ERROR_INVAL;
201 #endif
202 token = jsmn_alloc_token(parser, tokens, num_tokens);
203 if (token == NULL)
204 return JSMN_ERROR_NOMEM;
205 if (parser->toksuper != -1)
206 tokens[parser->toksuper].size++;
207 token->type = (c == '{' ? JSMN_OBJECT : JSMN_ARRAY);
208 token->start = parser->pos;
209 parser->toksuper = parser->toknext - 1;
210 break;
211 case '}':
212 case ']':
213 #ifdef JSMN_STRICT
214 if (expecting_item)
215 return JSMN_ERROR_INVAL;
216 #endif
217 type = (c == '}' ? JSMN_OBJECT : JSMN_ARRAY);
218 for (i = parser->toknext - 1; i >= 0; i--) {
219 token = &tokens[i];
220 if (token->start != -1 && token->end == -1) {
221 if (token->type != type)
222 return JSMN_ERROR_INVAL;
223 parser->toksuper = -1;
224 token->end = parser->pos + 1;
225 break;
226 }
227 }
228 /* Error if unmatched closing bracket */
229 if (i == -1)
230 return JSMN_ERROR_INVAL;
231 for (; i >= 0; i--) {
232 token = &tokens[i];
233 if (token->start != -1 && token->end == -1) {
234 parser->toksuper = i;
235 break;
236 }
237 }
238 break;
239 case '\"':
240 #ifdef JSMN_STRICT
241 if (!expecting_item)
242 return JSMN_ERROR_INVAL;
243 expecting_item = 0;
244 #endif
245 r = jsmn_parse_string(parser, js, len, tokens,
246 num_tokens);
247 if (r < 0)
248 return r;
249 if (parser->toksuper != -1)
250 tokens[parser->toksuper].size++;
251 break;
252 case '\t':
253 case '\r':
254 case '\n':
255 case ' ':
256 break;
257 #ifdef JSMN_STRICT
258 case ':':
259 case ',':
260 if (expecting_item)
261 return JSMN_ERROR_INVAL;
262 expecting_item = 1;
263 break;
264 /*
265 * In strict mode primitives are:
266 * numbers and booleans.
267 */
268 case '-':
269 case '0':
270 case '1':
271 case '2':
272 case '3':
273 case '4':
274 case '5':
275 case '6':
276 case '7':
277 case '8':
278 case '9':
279 case 't':
280 case 'f':
281 case 'n':
282 #else
283 case ':':
284 case ',':
285 break;
286 /*
287 * In non-strict mode every unquoted value
288 * is a primitive.
289 */
290 /*FALL THROUGH */
291 default:
292 #endif
293
294 #ifdef JSMN_STRICT
295 if (!expecting_item)
296 return JSMN_ERROR_INVAL;
297 expecting_item = 0;
298 #endif
299 r = jsmn_parse_primitive(parser, js, len, tokens,
300 num_tokens);
301 if (r < 0)
302 return r;
303 if (parser->toksuper != -1)
304 tokens[parser->toksuper].size++;
305 break;
306
307 #ifdef JSMN_STRICT
308 /* Unexpected char in strict mode */
309 default:
310 return JSMN_ERROR_INVAL;
311 #endif
312 }
313 }
314
315 for (i = parser->toknext - 1; i >= 0; i--) {
316 /* Unmatched opened object or array */
317 if (tokens[i].start != -1 && tokens[i].end == -1)
318 return JSMN_ERROR_PART;
319 }
320
321 #ifdef JSMN_STRICT
322 return expecting_item ? JSMN_ERROR_INVAL : JSMN_SUCCESS;
323 #else
324 return JSMN_SUCCESS;
325 #endif
326 }
327
328 /*
329 * Creates a new parser based over a given buffer with an array of tokens
330 * available.
331 */
jsmn_init(jsmn_parser * parser)332 void jsmn_init(jsmn_parser *parser)
333 {
334 parser->pos = 0;
335 parser->toknext = 0;
336 parser->toksuper = -1;
337 }
338
jsmn_strerror(jsmnerr_t err)339 const char *jsmn_strerror(jsmnerr_t err)
340 {
341 switch (err) {
342 case JSMN_ERROR_NOMEM:
343 return "No enough tokens";
344 case JSMN_ERROR_INVAL:
345 return "Invalid character inside JSON string";
346 case JSMN_ERROR_PART:
347 return "The string is not a full JSON packet, more bytes expected";
348 case JSMN_SUCCESS:
349 return "Success";
350 default:
351 return "Unknown json error";
352 }
353 }
354