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 */
31static 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 */
47static 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 */
59static 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
102found:
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 */
116static 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 */
173jsmnerr_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 */
292void jsmn_init(jsmn_parser *parser)
293{
294	parser->pos = 0;
295	parser->toknext = 0;
296	parser->toksuper = -1;
297}
298
299const 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