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_INTEGER 257
19 #define JSON_TOKEN_REAL 258
20 #define JSON_TOKEN_TRUE 259
21 #define JSON_TOKEN_FALSE 260
22 #define JSON_TOKEN_NULL 261
37 /*** error reporting ***/
39 static void json_set_error(json_error_t *error, const json_lex *lex,
43 char text[JSON_ERROR_TEXT_LENGTH];
49 vsnprintf(text, JSON_ERROR_TEXT_LENGTH, msg, ap);
54 error->line = lex->line;
57 int n = (int)(lex->input - lex->start);
58 snprintf(error->text, JSON_ERROR_TEXT_LENGTH,
59 "%s near '%.*s'", text, n, lex->start);
63 snprintf(error->text, JSON_ERROR_TEXT_LENGTH,
64 "%s near end of file", text);
70 snprintf(error->text, JSON_ERROR_TEXT_LENGTH, "%s", text);
75 /*** lexical analyzer ***/
77 static void json_scan_string(json_lex *lex)
80 const char *p = lex->input + 1;
83 lex->token = JSON_TOKEN_INVALID;
87 /* unterminated string literal */
91 if(0 <= *p && *p <= 31) {
92 /* control character */
99 for(int i = 0; i < 4; i++, p++) {
104 if(*p == '"' || *p == '\\' || *p == '/' || *p == 'b' ||
105 *p == 'f' || *p == 'n' || *p == 'r' || *p == 't')
114 /* the actual value is at most of the same length as the source
116 lex->value.string = malloc(p - lex->start);
117 if(!lex->value.string) {
118 /* this is not very nice, since TOKEN_INVALID is returned */
123 t = lex->value.string;
130 /* TODO: \uXXXX not supported yet */
131 free(lex->value.string);
132 lex->value.string = NULL;
136 case '"': case '\\': case '/':
138 case 'b': *t = '\b'; break;
139 case 'f': *t = '\f'; break;
140 case 'n': *t = '\n'; break;
141 case 'r': *t = '\r'; break;
142 case 't': *t = '\t'; break;
157 lex->token = JSON_TOKEN_STRING;
163 static void json_scan_number(json_lex *lex)
165 const char *p = lex->input;
168 lex->token = JSON_TOKEN_INVALID;
175 else /* *p != '0' */ {
182 lex->token = JSON_TOKEN_INTEGER;
184 lex->value.integer = strtol(lex->start, &end, 10);
190 else /* *p == '.' */ {
199 if(*p == 'E' || *p == 'e') {
201 if(*p == '+' || *p == '-')
211 lex->token = JSON_TOKEN_REAL;
213 lex->value.real = strtod(lex->start, &end);
220 static int json_lex_scan(json_lex *lex)
224 if(lex->token == JSON_TOKEN_STRING) {
225 free(lex->value.string);
226 lex->value.string = NULL;
229 while(isspace(*lex->input)) {
230 if(*lex->input == '\n')
236 lex->start = lex->input;
240 lex->token = JSON_TOKEN_EOF;
242 else if(c == '{' || c == '}' || c == '[' || c == ']' ||
243 c == ':' || c == ',') {
249 json_scan_string(lex);
251 else if(isdigit(c) || c == '-')
252 json_scan_number(lex);
254 else if(isalpha(c)) {
255 /* eat up the whole identifier for clearer error messages */
258 while(isalpha(*lex->input))
260 len = lex->input - lex->start;
262 if(strncmp(lex->start, "true", len) == 0)
263 lex->token = JSON_TOKEN_TRUE;
264 else if(strncmp(lex->start, "false", len) == 0)
265 lex->token = JSON_TOKEN_FALSE;
266 else if(strncmp(lex->start, "null", len) == 0)
267 lex->token = JSON_TOKEN_NULL;
269 lex->token = JSON_TOKEN_INVALID;
273 lex->token = JSON_TOKEN_INVALID;
280 static int json_lex_init(json_lex *lex, const char *input)
283 lex->token = JSON_TOKEN_INVALID;
290 static void json_lex_close(json_lex *lex)
292 if(lex->token == JSON_TOKEN_STRING)
293 free(lex->value.string);
299 static json_t *json_parse(json_lex *lex, json_error_t *error);
301 static json_t *json_parse_object(json_lex *lex, json_error_t *error)
303 json_t *object = json_object();
308 if(lex->token == '}')
315 if(lex->token != JSON_TOKEN_STRING) {
316 json_set_error(error, lex, "string expected");
320 key = strdup(lex->value.string);
325 if(lex->token != ':') {
327 json_set_error(error, lex, "':' expected");
333 value = json_parse(lex, error);
339 if(json_object_set(object, key, value)) {
348 if(lex->token != ',')
354 if(lex->token != '}') {
355 json_set_error(error, lex, "'}' expected");
366 static json_t *json_parse_array(json_lex *lex, json_error_t *error)
368 json_t *array = json_array();
373 if(lex->token == ']')
377 json_t *elem = json_parse(lex, error);
381 if(json_array_append(array, elem)) {
387 if(lex->token != ',')
394 if(lex->token != ']') {
395 json_set_error(error, lex, "']' expected");
406 static json_t *json_parse(json_lex *lex, json_error_t *error)
411 case JSON_TOKEN_STRING: {
412 json = json_string(lex->value.string);
416 case JSON_TOKEN_INTEGER: {
417 json = json_integer(lex->value.integer);
421 case JSON_TOKEN_REAL: {
422 json = json_real(lex->value.real);
426 case JSON_TOKEN_TRUE:
430 case JSON_TOKEN_FALSE:
434 case JSON_TOKEN_NULL:
439 json = json_parse_object(lex, error);
443 json = json_parse_array(lex, error);
446 case JSON_TOKEN_INVALID:
447 json_set_error(error, lex, "invalid token");
451 json_set_error(error, lex, "unexpected token");
462 json_t *json_load(const char *path, json_error_t *error)
467 fp = fopen(path, "r");
470 json_set_error(error, NULL, "unable to open %s: %s",
471 path, strerror(errno));
475 result = json_loadf(fp, error);
481 json_t *json_loads(const char *string, json_error_t *error)
484 json_t *result = NULL;
486 if(json_lex_init(&lex, string))
489 if(lex.token != '[' && lex.token != '{') {
490 json_set_error(error, &lex, "'[' or '{' expected");
494 result = json_parse(&lex, error);
498 if(lex.token != JSON_TOKEN_EOF) {
499 json_set_error(error, &lex, "end of file expected");
505 json_lex_close(&lex);
509 #define BUFFER_SIZE 4096
511 json_t *json_loadf(FILE *input, json_error_t *error)
514 char buffer[BUFFER_SIZE];
516 json_t *result = NULL;
518 if(strbuffer_init(&strbuff))
523 length = fread(buffer, 1, BUFFER_SIZE, input);
528 json_set_error(error, NULL, "read error");
533 if(strbuffer_append_bytes(&strbuff, buffer, length))
537 result = json_loads(strbuffer_value(&strbuff), error);
540 strbuffer_close(&strbuff);
544 json_t *json_loadfd(int fd, json_error_t *error)
547 char buffer[BUFFER_SIZE];
549 json_t *result = NULL;
551 if(strbuffer_init(&strbuff))
556 length = read(fd, buffer, BUFFER_SIZE);
559 json_set_error(error, NULL, "read error: %s", strerror(errno));
565 if(strbuffer_append_bytes(&strbuff, buffer, length))
567 json_set_error(error, NULL, "error allocating memory");
572 result = json_loads(strbuffer_value(&strbuff), error);
575 strbuffer_close(&strbuff);