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 #include <stdlib.h>
26 #include "jsmn.h"
27
28 /*
29 * Allocates a fresh unused token from the token pool.
30 */
jsmn_alloc_token(jsmn_parser * parser,jsmntok_t * tokens,size_t num_tokens)31 static jsmntok_t *jsmn_alloc_token(jsmn_parser *parser,
32 jsmntok_t *tokens, size_t num_tokens)
33 {
34 jsmntok_t *tok;
35
36 if ((unsigned)parser->toknext >= num_tokens)
37 return NULL;
38 tok = &tokens[parser->toknext++];
39 tok->start = tok->end = -1;
40 tok->size = 0;
41 return tok;
42 }
43
44 /*
45 * Fills token type and boundaries.
46 */
jsmn_fill_token(jsmntok_t * token,jsmntype_t type,int start,int end)47 static void jsmn_fill_token(jsmntok_t *token, jsmntype_t type,
48 int start, int end)
49 {
50 token->type = type;
51 token->start = start;
52 token->end = end;
53 token->size = 0;
54 }
55
56 /*
57 * Fills next available token with JSON primitive.
58 */
jsmn_parse_primitive(jsmn_parser * parser,const char * js,size_t len,jsmntok_t * tokens,size_t num_tokens)59 static jsmnerr_t jsmn_parse_primitive(jsmn_parser *parser, const char *js,
60 size_t len,
61 jsmntok_t *tokens, size_t num_tokens)
62 {
63 jsmntok_t *token;
64 int start;
65
66 start = parser->pos;
67
68 for (; parser->pos < len; parser->pos++) {
69 switch (js[parser->pos]) {
70 #ifndef JSMN_STRICT
71 /*
72 * In strict mode primitive must be followed by ","
73 * or "}" or "]"
74 */
75 case ':':
76 #endif
77 case '\t':
78 case '\r':
79 case '\n':
80 case ' ':
81 case ',':
82 case ']':
83 case '}':
84 goto found;
85 default:
86 break;
87 }
88 if (js[parser->pos] < 32 || js[parser->pos] >= 127) {
89 parser->pos = start;
90 return JSMN_ERROR_INVAL;
91 }
92 }
93 #ifdef JSMN_STRICT
94 /*
95 * In strict mode primitive must be followed by a
96 * comma/object/array.
97 */
98 parser->pos = start;
99 return JSMN_ERROR_PART;
100 #endif
101
102 found:
103 token = jsmn_alloc_token(parser, tokens, num_tokens);
104 if (token == NULL) {
105 parser->pos = start;
106 return JSMN_ERROR_NOMEM;
107 }
108 jsmn_fill_token(token, JSMN_PRIMITIVE, start, parser->pos);
109 parser->pos--; /* parent sees closing brackets */
110 return JSMN_SUCCESS;
111 }
112
113 /*
114 * Fills next token with JSON string.
115 */
jsmn_parse_string(jsmn_parser * parser,const char * js,size_t len,jsmntok_t * tokens,size_t num_tokens)116 static jsmnerr_t jsmn_parse_string(jsmn_parser *parser, const char *js,
117 size_t len,
118 jsmntok_t *tokens, size_t num_tokens)
119 {
120 jsmntok_t *token;
121 int start = parser->pos;
122
123 /* Skip starting quote */
124 parser->pos++;
125
126 for (; parser->pos < len; parser->pos++) {
127 char c = js[parser->pos];
128
129 /* Quote: end of string */
130 if (c == '\"') {
131 token = jsmn_alloc_token(parser, tokens, num_tokens);
132 if (token == NULL) {
133 parser->pos = start;
134 return JSMN_ERROR_NOMEM;
135 }
136 jsmn_fill_token(token, JSMN_STRING, start+1,
137 parser->pos);
138 return JSMN_SUCCESS;
139 }
140
141 /* Backslash: Quoted symbol expected */
142 if (c == '\\') {
143 parser->pos++;
144 switch (js[parser->pos]) {
145 /* Allowed escaped symbols */
146 case '\"':
147 case '/':
148 case '\\':
149 case 'b':
150 case 'f':
151 case 'r':
152 case 'n':
153 case 't':
154 break;
155 /* Allows escaped symbol \uXXXX */
156 case 'u':
157 /* TODO */
158 break;
159 /* Unexpected symbol */
160 default:
161 parser->pos = start;
162 return JSMN_ERROR_INVAL;
163 }
164 }
165 }
166 parser->pos = start;
167 return JSMN_ERROR_PART;
168 }
169
170 /*
171 * Parse JSON string and fill tokens.
172 */
jsmn_parse(jsmn_parser * parser,const char * js,size_t len,jsmntok_t * tokens,unsigned int num_tokens)173 jsmnerr_t jsmn_parse(jsmn_parser *parser, const char *js, size_t len,
174 jsmntok_t *tokens, unsigned int num_tokens)
175 {
176 jsmnerr_t r;
177 int i;
178 jsmntok_t *token;
179
180 for (; parser->pos < len; parser->pos++) {
181 char c;
182 jsmntype_t type;
183
184 c = js[parser->pos];
185 switch (c) {
186 case '{':
187 case '[':
188 token = jsmn_alloc_token(parser, tokens, num_tokens);
189 if (token == NULL)
190 return JSMN_ERROR_NOMEM;
191 if (parser->toksuper != -1)
192 tokens[parser->toksuper].size++;
193 token->type = (c == '{' ? JSMN_OBJECT : JSMN_ARRAY);
194 token->start = parser->pos;
195 parser->toksuper = parser->toknext - 1;
196 break;
197 case '}':
198 case ']':
199 type = (c == '}' ? JSMN_OBJECT : JSMN_ARRAY);
200 for (i = parser->toknext - 1; i >= 0; i--) {
201 token = &tokens[i];
202 if (token->start != -1 && token->end == -1) {
203 if (token->type != type)
204 return JSMN_ERROR_INVAL;
205 parser->toksuper = -1;
206 token->end = parser->pos + 1;
207 break;
208 }
209 }
210 /* Error if unmatched closing bracket */
211 if (i == -1)
212 return JSMN_ERROR_INVAL;
213 for (; i >= 0; i--) {
214 token = &tokens[i];
215 if (token->start != -1 && token->end == -1) {
216 parser->toksuper = i;
217 break;
218 }
219 }
220 break;
221 case '\"':
222 r = jsmn_parse_string(parser, js, len, tokens,
223 num_tokens);
224 if (r < 0)
225 return r;
226 if (parser->toksuper != -1)
227 tokens[parser->toksuper].size++;
228 break;
229 case '\t':
230 case '\r':
231 case '\n':
232 case ':':
233 case ',':
234 case ' ':
235 break;
236 #ifdef JSMN_STRICT
237 /*
238 * In strict mode primitives are:
239 * numbers and booleans.
240 */
241 case '-':
242 case '0':
243 case '1':
244 case '2':
245 case '3':
246 case '4':
247 case '5':
248 case '6':
249 case '7':
250 case '8':
251 case '9':
252 case 't':
253 case 'f':
254 case 'n':
255 #else
256 /*
257 * In non-strict mode every unquoted value
258 * is a primitive.
259 */
260 /*FALL THROUGH */
261 default:
262 #endif
263 r = jsmn_parse_primitive(parser, js, len, tokens,
264 num_tokens);
265 if (r < 0)
266 return r;
267 if (parser->toksuper != -1)
268 tokens[parser->toksuper].size++;
269 break;
270
271 #ifdef JSMN_STRICT
272 /* Unexpected char in strict mode */
273 default:
274 return JSMN_ERROR_INVAL;
275 #endif
276 }
277 }
278
279 for (i = parser->toknext - 1; i >= 0; i--) {
280 /* Unmatched opened object or array */
281 if (tokens[i].start != -1 && tokens[i].end == -1)
282 return JSMN_ERROR_PART;
283 }
284
285 return JSMN_SUCCESS;
286 }
287
288 /*
289 * Creates a new parser based over a given buffer with an array of tokens
290 * available.
291 */
jsmn_init(jsmn_parser * parser)292 void jsmn_init(jsmn_parser *parser)
293 {
294 parser->pos = 0;
295 parser->toknext = 0;
296 parser->toksuper = -1;
297 }
298
jsmn_strerror(jsmnerr_t err)299 const char *jsmn_strerror(jsmnerr_t err)
300 {
301 switch (err) {
302 case JSMN_ERROR_NOMEM:
303 return "No enough tokens";
304 case JSMN_ERROR_INVAL:
305 return "Invalid character inside JSON string";
306 case JSMN_ERROR_PART:
307 return "The string is not a full JSON packet, more bytes expected";
308 case JSMN_SUCCESS:
309 return "Success";
310 default:
311 return "Unknown json error";
312 }
313 }
314