PipeWire  0.3.61
json.h
Go to the documentation of this file.
1 /* Simple Plugin API
2  *
3  * Copyright © 2020 Wim Taymans
4  *
5  * Permission is hereby granted, free of charge, to any person obtaining a
6  * copy of this software and associated documentation files (the "Software"),
7  * to deal in the Software without restriction, including without limitation
8  * the rights to use, copy, modify, merge, publish, distribute, sublicense,
9  * and/or sell copies of the Software, and to permit persons to whom the
10  * Software is furnished to do so, subject to the following conditions:
11  *
12  * The above copyright notice and this permission notice (including the next
13  * paragraph) shall be included in all copies or substantial portions of the
14  * Software.
15  *
16  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
17  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
18  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
19  * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
20  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
21  * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
22  * DEALINGS IN THE SOFTWARE.
23  */
24 
25 #ifndef SPA_UTILS_JSON_H
26 #define SPA_UTILS_JSON_H
27 
28 #ifdef __cplusplus
29 extern "C" {
30 #else
31 #include <stdbool.h>
32 #endif
33 #include <stddef.h>
34 #include <stdlib.h>
35 #include <stdint.h>
36 #include <string.h>
37 #include <math.h>
38 #include <float.h>
39 
40 #include <spa/utils/defs.h>
41 #include <spa/utils/string.h>
42 
52 /* a simple JSON compatible tokenizer */
53 struct spa_json {
54  const char *cur;
55  const char *end;
56  struct spa_json *parent;
57  uint32_t state;
58  uint32_t depth;
59 };
60 
61 #define SPA_JSON_INIT(data,size) ((struct spa_json) { (data), (data)+(size), })
62 
63 static inline void spa_json_init(struct spa_json * iter, const char *data, size_t size)
64 {
65  *iter = SPA_JSON_INIT(data, size);
66 }
67 #define SPA_JSON_ENTER(iter) ((struct spa_json) { (iter)->cur, (iter)->end, (iter), })
68 
69 static inline void spa_json_enter(struct spa_json * iter, struct spa_json * sub)
70 {
71  *sub = SPA_JSON_ENTER(iter);
72 }
73 
74 #define SPA_JSON_SAVE(iter) ((struct spa_json) { (iter)->cur, (iter)->end, })
75 
78 static inline int spa_json_next(struct spa_json * iter, const char **value)
79 {
80  int utf8_remain = 0;
81  enum { __NONE, __STRUCT, __BARE, __STRING, __UTF8, __ESC, __COMMENT };
82 
83  *value = iter->cur;
84  for (; iter->cur < iter->end; iter->cur++) {
85  unsigned char cur = (unsigned char)*iter->cur;
86  again:
87  switch (iter->state) {
88  case __NONE:
89  iter->state = __STRUCT;
90  iter->depth = 0;
91  goto again;
92  case __STRUCT:
93  switch (cur) {
94  case '\0': case '\t': case ' ': case '\r': case '\n': case ':': case '=': case ',':
95  continue;
96  case '#':
97  iter->state = __COMMENT;
98  continue;
99  case '"':
100  *value = iter->cur;
101  iter->state = __STRING;
102  continue;
103  case '[': case '{':
104  *value = iter->cur;
105  if (++iter->depth > 1)
106  continue;
107  iter->cur++;
108  return 1;
109  case '}': case ']':
110  if (iter->depth == 0) {
111  if (iter->parent)
112  iter->parent->cur = iter->cur;
113  return 0;
114  }
115  --iter->depth;
116  continue;
117  default:
118  *value = iter->cur;
119  iter->state = __BARE;
120  }
121  continue;
122  case __BARE:
123  switch (cur) {
124  case '\t': case ' ': case '\r': case '\n':
125  case ':': case ',': case '=': case ']': case '}':
126  iter->state = __STRUCT;
127  if (iter->depth > 0)
128  goto again;
129  return iter->cur - *value;
130  }
131  continue;
132  case __STRING:
133  switch (cur) {
134  case '\\':
135  iter->state = __ESC;
136  continue;
137  case '"':
138  iter->state = __STRUCT;
139  if (iter->depth > 0)
140  continue;
141  return ++iter->cur - *value;
142  case 240 ... 247:
143  utf8_remain++;
145  case 224 ... 239:
146  utf8_remain++;
148  case 192 ... 223:
149  utf8_remain++;
150  iter->state = __UTF8;
151  continue;
152  default:
153  if (cur >= 32 && cur <= 126)
154  continue;
155  }
156  return -1;
157  case __UTF8:
158  switch (cur) {
159  case 128 ... 191:
160  if (--utf8_remain == 0)
161  iter->state = __STRING;
162  continue;
163  }
164  return -1;
165  case __ESC:
166  switch (cur) {
167  case '"': case '\\': case '/': case 'b': case 'f':
168  case 'n': case 'r': case 't': case 'u':
169  iter->state = __STRING;
170  continue;
171  }
172  return -1;
173  case __COMMENT:
174  switch (cur) {
175  case '\n': case '\r':
176  iter->state = __STRUCT;
177  }
178  }
179 
180  }
181  if (iter->depth != 0)
182  return -1;
183  if (iter->state != __STRUCT) {
184  iter->state = __STRUCT;
185  return iter->cur - *value;
186  }
187  return 0;
188 }
189 
190 static inline int spa_json_enter_container(struct spa_json *iter, struct spa_json *sub, char type)
191 {
192  const char *value;
193  if (spa_json_next(iter, &value) <= 0 || *value != type)
194  return -1;
195  spa_json_enter(iter, sub);
196  return 1;
197 }
198 
199 static inline int spa_json_is_container(const char *val, int len)
200 {
201  return len > 0 && (*val == '{' || *val == '[');
202 }
203 
204 static inline int spa_json_container_len(struct spa_json *iter, const char *value, int len)
205 {
206  const char *val;
207  struct spa_json sub;
208  spa_json_enter(iter, &sub);
209  while (spa_json_next(&sub, &val) > 0);
210  return sub.cur + 1 - value;
211 }
212 
213 /* object */
214 static inline int spa_json_is_object(const char *val, int len)
215 {
216  return len > 0 && *val == '{';
217 }
218 static inline int spa_json_enter_object(struct spa_json *iter, struct spa_json *sub)
219 {
220  return spa_json_enter_container(iter, sub, '{');
221 }
222 
223 /* array */
224 static inline bool spa_json_is_array(const char *val, int len)
225 {
226  return len > 0 && *val == '[';
227 }
228 static inline int spa_json_enter_array(struct spa_json *iter, struct spa_json *sub)
229 {
230  return spa_json_enter_container(iter, sub, '[');
231 }
232 
233 /* null */
234 static inline bool spa_json_is_null(const char *val, int len)
235 {
236  return len == 4 && strncmp(val, "null", 4) == 0;
237 }
238 
239 /* float */
240 static inline int spa_json_parse_float(const char *val, int len, float *result)
241 {
242  char *end;
243  if (strspn(val, "+-0123456789.Ee") < (size_t)len)
244  return 0;
245  *result = spa_strtof(val, &end);
246  return len > 0 && end == val + len;
247 }
248 
249 static inline bool spa_json_is_float(const char *val, int len)
250 {
251  float dummy;
252  return spa_json_parse_float(val, len, &dummy);
253 }
254 static inline int spa_json_get_float(struct spa_json *iter, float *res)
255 {
256  const char *value;
257  int len;
258  if ((len = spa_json_next(iter, &value)) <= 0)
259  return -1;
260  return spa_json_parse_float(value, len, res);
261 }
262 
263 static inline char *spa_json_format_float(char *str, int size, float val)
264 {
265  if (SPA_UNLIKELY(!isnormal(val))) {
266  if (val == INFINITY)
267  val = FLT_MAX;
268  else if (val == -INFINITY)
269  val = FLT_MIN;
270  else
271  val = 0.0f;
272  }
273  return spa_dtoa(str, size, val);
274 }
275 
276 /* int */
277 static inline int spa_json_parse_int(const char *val, int len, int *result)
278 {
279  char *end;
280  *result = strtol(val, &end, 0);
281  return len > 0 && end == val + len;
282 }
283 static inline bool spa_json_is_int(const char *val, int len)
284 {
285  int dummy;
286  return spa_json_parse_int(val, len, &dummy);
287 }
288 static inline int spa_json_get_int(struct spa_json *iter, int *res)
289 {
290  const char *value;
291  int len;
292  if ((len = spa_json_next(iter, &value)) <= 0)
293  return -1;
294  return spa_json_parse_int(value, len, res);
295 }
296 
297 /* bool */
298 static inline bool spa_json_is_true(const char *val, int len)
299 {
300  return len == 4 && strncmp(val, "true", 4) == 0;
301 }
302 
303 static inline bool spa_json_is_false(const char *val, int len)
304 {
305  return len == 5 && strncmp(val, "false", 5) == 0;
306 }
307 
308 static inline bool spa_json_is_bool(const char *val, int len)
309 {
310  return spa_json_is_true(val, len) || spa_json_is_false(val, len);
311 }
312 
313 static inline int spa_json_parse_bool(const char *val, int len, bool *result)
314 {
315  if ((*result = spa_json_is_true(val, len)))
316  return 1;
317  if (!(*result = !spa_json_is_false(val, len)))
318  return 1;
319  return -1;
320 }
321 static inline int spa_json_get_bool(struct spa_json *iter, bool *res)
322 {
323  const char *value;
324  int len;
325  if ((len = spa_json_next(iter, &value)) <= 0)
326  return -1;
327  return spa_json_parse_bool(value, len, res);
328 }
329 
330 /* string */
331 static inline bool spa_json_is_string(const char *val, int len)
332 {
333  return len > 1 && *val == '"';
334 }
335 
336 static inline int spa_json_parse_hex(const char *p, int num, uint32_t *res)
337 {
338  int i;
339  *res = 0;
340  for (i = 0; i < num; i++) {
341  char v = p[i];
342  if (v >= '0' && v <= '9')
343  v = v - '0';
344  else if (v >= 'a' && v <= 'f')
345  v = v - 'a' + 10;
346  else if (v >= 'A' && v <= 'F')
347  v = v - 'A' + 10;
348  else
349  return -1;
350  *res = (*res << 4) | v;
351  }
352  return 1;
353 }
354 
355 static inline int spa_json_parse_stringn(const char *val, int len, char *result, int maxlen)
356 {
357  const char *p;
358  if (maxlen <= len)
359  return -1;
360  if (!spa_json_is_string(val, len)) {
361  if (result != val)
362  strncpy(result, val, len);
363  result += len;
364  } else {
365  for (p = val+1; p < val + len; p++) {
366  if (*p == '\\') {
367  p++;
368  if (*p == 'n')
369  *result++ = '\n';
370  else if (*p == 'r')
371  *result++ = '\r';
372  else if (*p == 'b')
373  *result++ = '\b';
374  else if (*p == 't')
375  *result++ = '\t';
376  else if (*p == 'f')
377  *result++ = '\f';
378  else if (*p == 'u') {
379  uint8_t prefix[] = { 0, 0xc0, 0xe0, 0xf0 };
380  uint32_t idx, n, v, cp, enc[] = { 0x80, 0x800, 0x10000 };
381  if (val + len - p < 5 ||
382  spa_json_parse_hex(p+1, 4, &cp) < 0) {
383  *result++ = *p;
384  continue;
385  }
386  p += 4;
387 
388  if (cp >= 0xd800 && cp <= 0xdbff) {
389  if (val + len - p < 7 ||
390  p[1] != '\\' || p[2] != 'u' ||
391  spa_json_parse_hex(p+3, 4, &v) < 0 ||
392  v < 0xdc00 || v > 0xdfff)
393  continue;
394  p += 6;
395  cp = 0x010000 | ((cp & 0x3ff) << 10) | (v & 0x3ff);
396  } else if (cp >= 0xdc00 && cp <= 0xdfff)
397  continue;
398 
399  for (idx = 0; idx < 3; idx++)
400  if (cp < enc[idx])
401  break;
402  for (n = idx; n > 0; n--, cp >>= 6)
403  result[n] = (cp | 0x80) & 0xbf;
404  *result++ = (cp | prefix[idx]) & 0xff;
405  result += idx;
406  } else
407  *result++ = *p;
408  } else if (*p == '\"') {
409  break;
410  } else
411  *result++ = *p;
412  }
413  }
414  *result = '\0';
415  return 1;
416 }
417 
418 static inline int spa_json_parse_string(const char *val, int len, char *result)
419 {
420  return spa_json_parse_stringn(val, len, result, len+1);
421 }
422 
423 static inline int spa_json_get_string(struct spa_json *iter, char *res, int maxlen)
424 {
425  const char *value;
426  int len;
427  if ((len = spa_json_next(iter, &value)) <= 0)
428  return -1;
429  return spa_json_parse_stringn(value, len, res, maxlen);
430 }
431 
432 static inline int spa_json_encode_string(char *str, int size, const char *val)
433 {
434  int len = 0;
435  static const char hex[] = { "0123456789abcdef" };
436 #define __PUT(c) { if (len < size) *str++ = c; len++; }
437  __PUT('"');
438  while (*val) {
439  switch (*val) {
440  case '\n':
441  __PUT('\\'); __PUT('n');
442  break;
443  case '\r':
444  __PUT('\\'); __PUT('r');
445  break;
446  case '\b':
447  __PUT('\\'); __PUT('b');
448  break;
449  case '\t':
450  __PUT('\\'); __PUT('t');
451  break;
452  case '\f':
453  __PUT('\\'); __PUT('f');
454  break;
455  case '\\':
456  case '"':
457  __PUT('\\'); __PUT(*val);
458  break;
459  default:
460  if (*val > 0 && *val < 0x20) {
461  __PUT('\\'); __PUT('u');
462  __PUT('0'); __PUT('0');
463  __PUT(hex[((*val)>>4)&0xf]); __PUT(hex[(*val)&0xf]);
464  } else {
465  __PUT(*val);
466  }
467  break;
468  }
469  val++;
470  }
471  __PUT('"');
472  __PUT('\0');
473 #undef __PUT
474  return len-1;
475 }
476 
481 #ifdef __cplusplus
482 } /* extern "C" */
483 #endif
484 
485 #endif /* SPA_UTILS_JSON_H */
spa/utils/defs.h
static int spa_json_container_len(struct spa_json *iter, const char *value, int len)
Definition: json.h:212
static bool spa_json_is_string(const char *val, int len)
Definition: json.h:339
static bool spa_json_is_float(const char *val, int len)
Definition: json.h:257
static int spa_json_parse_float(const char *val, int len, float *result)
Definition: json.h:248
static bool spa_json_is_true(const char *val, int len)
Definition: json.h:306
static int spa_json_parse_stringn(const char *val, int len, char *result, int maxlen)
Definition: json.h:363
static int spa_json_enter_container(struct spa_json *iter, struct spa_json *sub, char type)
Definition: json.h:198
static void spa_json_enter(struct spa_json *iter, struct spa_json *sub)
Definition: json.h:76
static int spa_json_parse_hex(const char *p, int num, uint32_t *res)
Definition: json.h:344
static bool spa_json_is_false(const char *val, int len)
Definition: json.h:311
static int spa_json_get_int(struct spa_json *iter, int *res)
Definition: json.h:296
static int spa_json_parse_bool(const char *val, int len, bool *result)
Definition: json.h:321
static int spa_json_enter_object(struct spa_json *iter, struct spa_json *sub)
Definition: json.h:226
static int spa_json_get_string(struct spa_json *iter, char *res, int maxlen)
Definition: json.h:431
static bool spa_json_is_bool(const char *val, int len)
Definition: json.h:316
#define SPA_JSON_INIT(data, size)
Definition: json.h:67
static bool spa_json_is_array(const char *val, int len)
Definition: json.h:232
static int spa_json_get_bool(struct spa_json *iter, bool *res)
Definition: json.h:329
static bool spa_json_is_null(const char *val, int len)
Definition: json.h:242
#define SPA_JSON_ENTER(iter)
Definition: json.h:74
static int spa_json_encode_string(char *str, int size, const char *val)
Definition: json.h:440
static char * spa_json_format_float(char *str, int size, float val)
Definition: json.h:271
static int spa_json_parse_int(const char *val, int len, int *result)
Definition: json.h:285
static int spa_json_next(struct spa_json *iter, const char **value)
Get the next token.
Definition: json.h:86
static int spa_json_is_container(const char *val, int len)
Definition: json.h:207
static void spa_json_init(struct spa_json *iter, const char *data, size_t size)
Definition: json.h:69
static bool spa_json_is_int(const char *val, int len)
Definition: json.h:291
static int spa_json_enter_array(struct spa_json *iter, struct spa_json *sub)
Definition: json.h:236
static int spa_json_get_float(struct spa_json *iter, float *res)
Definition: json.h:262
static int spa_json_is_object(const char *val, int len)
Definition: json.h:222
static int spa_json_parse_string(const char *val, int len, char *result)
Definition: json.h:426
static float spa_strtof(const char *str, char **endptr)
Convert str to a float in the C locale.
Definition: string.h:281
static char * spa_dtoa(char *str, size_t size, double val)
Definition: string.h:374
#define SPA_UNLIKELY(x)
Definition: defs.h:355
#define SPA_FALLTHROUGH
SPA_FALLTHROUGH is an annotation to suppress compiler warnings about switch cases that fall through w...
Definition: defs.h:86
#define __PUT(c)
spa/utils/string.h
Definition: json.h:58
uint32_t depth
Definition: json.h:63
const char * cur
Definition: json.h:59
uint32_t state
Definition: json.h:62
const char * end
Definition: json.h:60
struct spa_json * parent
Definition: json.h:61