2 * $Id: json_tokener.h,v 1.10 2006/07/25 03:24:50 mclark Exp $
4 * Copyright (c) 2004, 2005 Metaparadigm Pte. Ltd.
5 * Michael Clark <michael@metaparadigm.com>
7 * This library is free software; you can redistribute it and/or modify
8 * it under the terms of the MIT license. See COPYING for details.
12 #ifndef _json_tokener_h_
13 #define _json_tokener_h_
16 #include "json_object.h"
22 enum json_tokener_error {
24 json_tokener_continue,
25 json_tokener_error_depth,
26 json_tokener_error_parse_eof,
27 json_tokener_error_parse_unexpected,
28 json_tokener_error_parse_null,
29 json_tokener_error_parse_boolean,
30 json_tokener_error_parse_number,
31 json_tokener_error_parse_array,
32 json_tokener_error_parse_object_key_name,
33 json_tokener_error_parse_object_key_sep,
34 json_tokener_error_parse_object_value_sep,
35 json_tokener_error_parse_string,
36 json_tokener_error_parse_comment,
37 json_tokener_error_size
40 enum json_tokener_state {
41 json_tokener_state_eatws,
42 json_tokener_state_start,
43 json_tokener_state_finish,
44 json_tokener_state_null,
45 json_tokener_state_comment_start,
46 json_tokener_state_comment,
47 json_tokener_state_comment_eol,
48 json_tokener_state_comment_end,
49 json_tokener_state_string,
50 json_tokener_state_string_escape,
51 json_tokener_state_escape_unicode,
52 json_tokener_state_boolean,
53 json_tokener_state_number,
54 json_tokener_state_array,
55 json_tokener_state_array_add,
56 json_tokener_state_array_sep,
57 json_tokener_state_object_field_start,
58 json_tokener_state_object_field,
59 json_tokener_state_object_field_end,
60 json_tokener_state_object_value,
61 json_tokener_state_object_value_add,
62 json_tokener_state_object_sep,
63 json_tokener_state_array_after_sep,
64 json_tokener_state_object_field_start_after_sep,
65 json_tokener_state_inf
68 struct json_tokener_srec
70 enum json_tokener_state state, saved_state;
71 struct json_object *obj;
72 struct json_object *current;
76 #define JSON_TOKENER_DEFAULT_DEPTH 32
82 int max_depth, depth, is_double, st_pos, char_offset;
83 enum json_tokener_error err;
84 unsigned int ucs_char;
86 struct json_tokener_srec *stack;
91 * Be strict when parsing JSON input. Use caution with
92 * this flag as what is considered valid may become more
93 * restrictive from one release to the next, causing your
94 * code to fail on previously working input.
96 * This flag is not set by default.
98 * @see json_tokener_set_flags()
100 #define JSON_TOKENER_STRICT 0x01
103 * Given an error previously returned by json_tokener_get_error(),
104 * return a human readable description of the error.
106 * @return a generic error message is returned if an invalid error value is provided.
108 const char *json_tokener_error_desc(enum json_tokener_error jerr);
111 * Retrieve the error caused by the last call to json_tokener_parse_ex(),
112 * or json_tokener_success if there is no error.
114 * When parsing a JSON string in pieces, if the tokener is in the middle
115 * of parsing this will return json_tokener_continue.
117 * See also json_tokener_error_desc().
119 enum json_tokener_error json_tokener_get_error(struct json_tokener *tok);
121 extern struct json_tokener* json_tokener_new(void);
122 extern struct json_tokener* json_tokener_new_ex(int depth);
123 extern void json_tokener_free(struct json_tokener *tok);
124 extern void json_tokener_reset(struct json_tokener *tok);
125 extern struct json_object* json_tokener_parse(const char *str);
126 extern struct json_object* json_tokener_parse_verbose(const char *str, enum json_tokener_error *error);
129 * Set flags that control how parsing will be done.
131 extern void json_tokener_set_flags(struct json_tokener *tok, int flags);
134 * Parse a string and return a non-NULL json_object if a valid JSON value
135 * is found. The string does not need to be a JSON object or array;
136 * it can also be a string, number or boolean value.
138 * A partial JSON string can be parsed. If the parsing is incomplete,
139 * NULL will be returned and json_tokener_get_error() will be return
140 * json_tokener_continue.
141 * json_tokener_parse_ex() can then be called with additional bytes in str
142 * to continue the parsing.
144 * If json_tokener_parse_ex() returns NULL and the error anything other than
145 * json_tokener_continue, a fatal error has occurred and parsing must be
146 * halted. Then tok object must not be re-used until json_tokener_reset() is
149 * When a valid JSON value is parsed, a non-NULL json_object will be
150 * returned. Also, json_tokener_get_error() will return json_tokener_success.
151 * Be sure to check the type with json_object_is_type() or
152 * json_object_get_type() before using the object.
154 * @b XXX this shouldn't use internal fields:
155 * Trailing characters after the parsed value do not automatically cause an
156 * error. It is up to the caller to decide whether to treat this as an
157 * error or to handle the additional characters, perhaps by parsing another
158 * json value starting from that point.
160 * Extra characters can be detected by comparing the tok->char_offset against
161 * the length of the last len parameter passed in.
163 * The tokener does \b not maintain an internal buffer so the caller is
164 * responsible for calling json_tokener_parse_ex with an appropriate str
165 * parameter starting with the extra characters.
167 * This interface is presently not 64-bit clean due to the int len argument
168 * so the function limits the maximum string size to INT32_MAX (2GB).
169 * If the function is called with len == -1 then strlen is called to check
170 * the string length is less than INT32_MAX (2GB)
174 json_object *jobj = NULL;
175 const char *mystring = NULL;
177 enum json_tokener_error jerr;
179 mystring = ... // get JSON string, e.g. read from file, etc...
180 stringlen = strlen(mystring);
181 jobj = json_tokener_parse_ex(tok, mystring, stringlen);
182 } while ((jerr = json_tokener_get_error(tok)) == json_tokener_continue);
183 if (jerr != json_tokener_success)
185 fprintf(stderr, "Error: %s\n", json_tokener_error_desc(jerr));
186 // Handle errors, as appropriate for your application.
188 if (tok->char_offset < stringlen) // XXX shouldn't access internal fields
190 // Handle extra characters after parsed object as desired.
191 // e.g. issue an error, parse another object from that point, etc...
193 // Success, use jobj here.
197 * @param tok a json_tokener previously allocated with json_tokener_new()
198 * @param str an string with any valid JSON expression, or portion of. This does not need to be null terminated.
199 * @param len the length of str
201 extern struct json_object* json_tokener_parse_ex(struct json_tokener *tok,
202 const char *str, int len);