12 #include "strbuffer.h"
15 #define JSON_TOKEN_INVALID -1
16 #define JSON_TOKEN_EOF 0
17 #define JSON_TOKEN_STRING 256
18 #define JSON_TOKEN_NUMBER 257
19 #define JSON_TOKEN_TRUE 258
20 #define JSON_TOKEN_FALSE 259
21 #define JSON_TOKEN_NULL 260
35 /*** error reporting ***/
37 static void json_set_error(json_error_t *error, const json_lex *lex,
41 char text[JSON_ERROR_TEXT_LENGTH];
47 vsnprintf(text, JSON_ERROR_TEXT_LENGTH, msg, ap);
52 error->line = lex->line;
55 int n = (int)(lex->input - lex->start);
56 snprintf(error->text, JSON_ERROR_TEXT_LENGTH,
57 "%s near '%.*s'", text, n, lex->start);
61 snprintf(error->text, JSON_ERROR_TEXT_LENGTH,
62 "%s near end of file", text);
66 snprintf(error->text, JSON_ERROR_TEXT_LENGTH, "%s", msg);
70 /*** lexical analyzer ***/
72 static void json_scan_string(json_lex *lex)
75 const char *p = lex->input + 1;
78 lex->token = JSON_TOKEN_INVALID;
82 /* unterminated string literal */
86 if(0 <= *p && *p <= 31) {
87 /* control character */
94 for(int i = 0; i < 4; i++, p++) {
99 if(*p == '"' || *p == '\\' || *p == '/' || *p == 'b' ||
100 *p == 'f' || *p == 'n' || *p == 'r' || *p == 't')
109 /* the actual value is at most of the same length as the source
111 lex->value.string = malloc(p - lex->start);
112 if(!lex->value.string) {
113 /* this is not very nice, since TOKEN_INVALID is returned */
118 t = lex->value.string;
125 /* TODO: \uXXXX not supported yet */
126 free(lex->value.string);
127 lex->value.string = NULL;
131 case '"': case '\\': case '/':
133 case 'b': *t = '\b'; break;
134 case 'f': *t = '\f'; break;
135 case 'n': *t = '\n'; break;
136 case 'r': *t = '\r'; break;
137 case 't': *t = '\t'; break;
152 lex->token = JSON_TOKEN_STRING;
158 static void json_scan_number(json_lex *lex)
160 const char *p = lex->input;
163 lex->token = JSON_TOKEN_INVALID;
170 else /* *p != '0' */ {
185 if(*p == 'E' || *p == 'e') {
187 if(*p == '+' || *p == '-')
197 lex->token = JSON_TOKEN_NUMBER;
199 lex->value.number = strtod(lex->start, &end);
206 static int json_lex_scan(json_lex *lex)
210 if(lex->token == JSON_TOKEN_STRING) {
211 free(lex->value.string);
212 lex->value.string = NULL;
215 while(isspace(*lex->input)) {
216 if(*lex->input == '\n')
222 lex->start = lex->input;
226 lex->token = JSON_TOKEN_EOF;
228 else if(c == '{' || c == '}' || c == '[' || c == ']' ||
229 c == ':' || c == ',') {
235 json_scan_string(lex);
237 else if(isdigit(c) || c == '-')
238 json_scan_number(lex);
240 else if(isalpha(c)) {
241 /* eat up the whole identifier for clearer error messages */
244 while(isalpha(*lex->input))
246 len = lex->input - lex->start;
248 if(strncmp(lex->start, "true", len) == 0)
249 lex->token = JSON_TOKEN_TRUE;
250 else if(strncmp(lex->start, "false", len) == 0)
251 lex->token = JSON_TOKEN_FALSE;
252 else if(strncmp(lex->start, "null", len) == 0)
253 lex->token = JSON_TOKEN_NULL;
255 lex->token = JSON_TOKEN_INVALID;
259 lex->token = JSON_TOKEN_INVALID;
266 static int json_lex_init(json_lex *lex, const char *input)
269 lex->token = JSON_TOKEN_INVALID;
276 static void json_lex_close(json_lex *lex)
278 if(lex->token == JSON_TOKEN_STRING)
279 free(lex->value.string);
285 static json_t *json_parse(json_lex *lex, json_error_t *error);
287 static json_t *json_parse_object(json_lex *lex, json_error_t *error)
289 json_t *object = json_object();
294 if(lex->token == '}')
301 if(lex->token != JSON_TOKEN_STRING) {
302 json_set_error(error, lex, "string expected");
306 key = strdup(lex->value.string);
311 if(lex->token != ':') {
312 json_set_error(error, lex, "':' expected");
318 value = json_parse(lex, error);
322 if(json_object_set(object, key, value)) {
330 if(lex->token != ',')
336 if(lex->token != '}') {
337 json_set_error(error, lex, "'}' expected");
348 static json_t *json_parse_array(json_lex *lex, json_error_t *error)
350 json_t *array = json_array();
355 if(lex->token != ']') {
357 json_t *elem = json_parse(lex, error);
361 if(json_array_append(array, elem)) {
367 if(lex->token != ',')
374 if(lex->token != ']') {
375 json_set_error(error, lex, "']' expected");
386 static json_t *json_parse(json_lex *lex, json_error_t *error)
391 case JSON_TOKEN_STRING: {
392 json = json_string(lex->value.string);
396 case JSON_TOKEN_NUMBER: {
397 json = json_number(lex->value.number);
401 case JSON_TOKEN_TRUE:
405 case JSON_TOKEN_FALSE:
409 case JSON_TOKEN_NULL:
414 json = json_parse_object(lex, error);
418 json = json_parse_array(lex, error);
421 case JSON_TOKEN_INVALID:
422 json_set_error(error, lex, "invalid token");
426 json_set_error(error, lex, "unexpected token");
437 json_t *json_load(const char *path, json_error_t *error)
442 fp = fopen(path, "r");
445 json_set_error(error, NULL, "unable to open %s: %s",
446 path, strerror(errno));
450 result = json_loadf(fp, error);
456 json_t *json_loads(const char *string, json_error_t *error)
459 json_t *result = NULL;
461 if(json_lex_init(&lex, string))
464 if(lex.token != '[' && lex.token != '{') {
465 json_set_error(error, &lex, "'[' or '{' expected");
469 result = json_parse(&lex, error);
473 if(lex.token != JSON_TOKEN_EOF) {
474 json_set_error(error, &lex, "end of file expected");
480 json_lex_close(&lex);
484 #define BUFFER_SIZE 4096
486 json_t *json_loadf(FILE *input, json_error_t *error)
489 char buffer[BUFFER_SIZE];
491 json_t *result = NULL;
493 strbuffer_init(&strbuff);
497 length = fread(buffer, 1, BUFFER_SIZE, input);
502 json_set_error(error, NULL, "read error");
507 if(strbuffer_append_bytes(&strbuff, buffer, length))
511 result = json_loads(strbuffer_value(&strbuff), error);
514 strbuffer_close(&strbuff);
518 json_t *json_loadfd(int fd, json_error_t *error)
521 char buffer[BUFFER_SIZE];
523 json_t *result = NULL;
525 strbuffer_init(&strbuff);
529 length = read(fd, buffer, BUFFER_SIZE);
532 json_set_error(error, NULL, "read error: %s", strerror(errno));
538 if(strbuffer_append_bytes(&strbuff, buffer, length))
540 json_set_error(error, NULL, "error allocating memory");
545 result = json_loads(strbuffer_value(&strbuff), error);
548 strbuffer_close(&strbuff);