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 /*
  * $Id: json_tokener.h,v 1.10 2006/07/25 03:24:50 mclark Exp $
  *
  * Copyright (c) 2004, 2005 Metaparadigm Pte. Ltd.
  * Michael Clark <michael@metaparadigm.com>
  *
  * This library is free software; you can redistribute it and/or modify
  * it under the terms of the MIT license. See COPYING for details.
  *
  */
 
 /**
  * @file
  * @brief Methods to parse an input string into a tree of json_object objects.
  */
 #ifndef _json_tokener_h_
 #define _json_tokener_h_
 
 #include "json_object.h"
 #include <stddef.h>
 
 #ifdef __cplusplus
 extern "C" {
 #endif
 
 enum json_tokener_error
 {
     json_tokener_success,
     json_tokener_continue,
     json_tokener_error_depth,
     json_tokener_error_parse_eof,
     json_tokener_error_parse_unexpected,
     json_tokener_error_parse_null,
     json_tokener_error_parse_boolean,
     json_tokener_error_parse_number,
     json_tokener_error_parse_array,
     json_tokener_error_parse_object_key_name,
     json_tokener_error_parse_object_key_sep,
     json_tokener_error_parse_object_value_sep,
     json_tokener_error_parse_string,
     json_tokener_error_parse_comment,
     json_tokener_error_parse_utf8_string,
     json_tokener_error_size,   /* A string longer than INT32_MAX was passed as input */
     json_tokener_error_memory  /* Failed to allocate memory */
 };
 
 /**
  * @deprecated Don't use this outside of json_tokener.c, it will be made private in a future release.
  */
 enum json_tokener_state
 {
     json_tokener_state_eatws,
     json_tokener_state_start,
     json_tokener_state_finish,
     json_tokener_state_null,
     json_tokener_state_comment_start,
     json_tokener_state_comment,
     json_tokener_state_comment_eol,
     json_tokener_state_comment_end,
     json_tokener_state_string,
     json_tokener_state_string_escape,
     json_tokener_state_escape_unicode,
     json_tokener_state_escape_unicode_need_escape,
     json_tokener_state_escape_unicode_need_u,
     json_tokener_state_boolean,
     json_tokener_state_number,
     json_tokener_state_array,
     json_tokener_state_array_add,
     json_tokener_state_array_sep,
     json_tokener_state_object_field_start,
     json_tokener_state_object_field,
     json_tokener_state_object_field_end,
     json_tokener_state_object_value,
     json_tokener_state_object_value_add,
     json_tokener_state_object_sep,
     json_tokener_state_array_after_sep,
     json_tokener_state_object_field_start_after_sep,
     json_tokener_state_inf
 };
 
 /**
  * @deprecated Don't use this outside of json_tokener.c, it will be made private in a future release.
  */
 struct json_tokener_srec
 {
     enum json_tokener_state state, saved_state;
     struct json_object *obj;
     struct json_object *current;
     char *obj_field_name;
 };
 
 #define JSON_TOKENER_DEFAULT_DEPTH 32
 
 /**
  * Internal state of the json parser.
  * Do not access any fields of this structure directly.
  * Its definition is published due to historical limitations
  * in the json tokener API, and will be changed to be an opaque
  * type in the future.
  */
 struct json_tokener
 {
     /**
      * @deprecated Do not access any of these fields outside of json_tokener.c
      */
     char *str;
     struct printbuf *pb;
     int max_depth, depth, is_double, st_pos;
     /**
      * @deprecated See json_tokener_get_parse_end() instead.
      */
     int char_offset;
     /**
      * @deprecated See json_tokener_get_error() instead.
      */
     enum json_tokener_error err;
     unsigned int ucs_char, high_surrogate;
     char quote_char;
     struct json_tokener_srec *stack;
     int flags;
 };
 
 /**
  * Return the offset of the byte after the last byte parsed
  * relative to the start of the most recent string passed in
  * to json_tokener_parse_ex().  i.e. this is where parsing
  * would start again if the input contains another JSON object
  * after the currently parsed one.
  *
  * Note that when multiple parse calls are issued, this is *not* the
  * total number of characters parsed.
  *
  * In the past this would have been accessed as tok->char_offset.
  *
  * See json_tokener_parse_ex() for an example of how to use this.
  */
 JSON_EXPORT size_t json_tokener_get_parse_end(struct json_tokener *tok);
 
 /**
  * @deprecated Unused in json-c code
  */
 typedef struct json_tokener json_tokener;
 
 /**
  * Be strict when parsing JSON input.  Use caution with
  * this flag as what is considered valid may become more
  * restrictive from one release to the next, causing your
  * code to fail on previously working input.
  *
  * Note that setting this will also effectively disable parsing
  * of multiple json objects in a single character stream
  * (e.g. {"foo":123}{"bar":234}); if you want to allow that
  * also set JSON_TOKENER_ALLOW_TRAILING_CHARS
  *
  * This flag is not set by default.
  *
  * @see json_tokener_set_flags()
  */
 #define JSON_TOKENER_STRICT 0x01
 
 /**
  * Use with JSON_TOKENER_STRICT to allow trailing characters after the
  * first parsed object.
  *
  * @see json_tokener_set_flags()
  */
 #define JSON_TOKENER_ALLOW_TRAILING_CHARS 0x02
 
 /**
  * Cause json_tokener_parse_ex() to validate that input is UTF8.
  * If this flag is specified and validation fails, then
  * json_tokener_get_error(tok) will return
  * json_tokener_error_parse_utf8_string
  *
  * This flag is not set by default.
  *
  * @see json_tokener_set_flags()
  */
 #define JSON_TOKENER_VALIDATE_UTF8 0x10
 
 /**
  * Given an error previously returned by json_tokener_get_error(),
  * return a human readable description of the error.
  *
  * @return a generic error message is returned if an invalid error value is provided.
  */
 JSON_EXPORT const char *json_tokener_error_desc(enum json_tokener_error jerr);
 
 /**
  * Retrieve the error caused by the last call to json_tokener_parse_ex(),
  * or json_tokener_success if there is no error.
  *
  * When parsing a JSON string in pieces, if the tokener is in the middle
  * of parsing this will return json_tokener_continue.
  *
  * @see json_tokener_error_desc().
  */
 JSON_EXPORT enum json_tokener_error json_tokener_get_error(struct json_tokener *tok);
 
 /**
  * Allocate a new json_tokener.
  * When done using that to parse objects, free it with json_tokener_free().
  * See json_tokener_parse_ex() for usage details.
  */
 JSON_EXPORT struct json_tokener *json_tokener_new(void);
 
 /**
  * Allocate a new json_tokener with a custom max nesting depth.
  * @see JSON_TOKENER_DEFAULT_DEPTH
  */
 JSON_EXPORT struct json_tokener *json_tokener_new_ex(int depth);
 
 /**
  * Free a json_tokener previously allocated with json_tokener_new().
  */
 JSON_EXPORT void json_tokener_free(struct json_tokener *tok);
 
 /**
  * Reset the state of a json_tokener, to prepare to parse a 
  * brand new JSON object.
  */
 JSON_EXPORT void json_tokener_reset(struct json_tokener *tok);
 
 /**
  * Parse a json_object out of the string `str`.
  *
  * If you need more control over how the parsing occurs,
  * see json_tokener_parse_ex().
  */
 JSON_EXPORT struct json_object *json_tokener_parse(const char *str);
 
 /**
  * Parse a json_object out of the string `str`, but if it fails
  * return the error in `*error`.
  * @see json_tokener_parse()
  * @see json_tokener_parse_ex()
  */
 JSON_EXPORT struct json_object *json_tokener_parse_verbose(const char *str,
                                                            enum json_tokener_error *error);
 
 /**
  * Set flags that control how parsing will be done.
  */
 JSON_EXPORT void json_tokener_set_flags(struct json_tokener *tok, int flags);
 
 /**
  * Parse a string and return a non-NULL json_object if a valid JSON value
  * is found.  The string does not need to be a JSON object or array;
  * it can also be a string, number or boolean value.
  *
  * A partial JSON string can be parsed.  If the parsing is incomplete,
  * NULL will be returned and json_tokener_get_error() will return
  * json_tokener_continue.
  * json_tokener_parse_ex() can then be called with additional bytes in str
  * to continue the parsing.
  *
  * If json_tokener_parse_ex() returns NULL and the error is anything other than
  * json_tokener_continue, a fatal error has occurred and parsing must be
  * halted.  Then, the tok object must not be reused until json_tokener_reset()
  * is called.
  *
  * When a valid JSON value is parsed, a non-NULL json_object will be
  * returned, with a reference count of one which belongs to the caller.  Also,
  * json_tokener_get_error() will return json_tokener_success. Be sure to check
  * the type with json_object_is_type() or json_object_get_type() before using
  * the object.
  *
  * Trailing characters after the parsed value do not automatically cause an
  * error.  It is up to the caller to decide whether to treat this as an
  * error or to handle the additional characters, perhaps by parsing another
  * json value starting from that point.
  *
  * If the caller knows that they are at the end of their input, the length
  * passed MUST include the final '\0' character, so values with no inherent
  * end (i.e. numbers) can be properly parsed, rather than just returning
  * json_tokener_continue.
  *
  * Extra characters can be detected by comparing the value returned by
  * json_tokener_get_parse_end() against
  * the length of the last len parameter passed in.
  *
  * The tokener does \b not maintain an internal buffer so the caller is
  * responsible for a subsequent call to json_tokener_parse_ex with an 
  * appropriate str parameter starting with the extra characters.
  *
  * This interface is presently not 64-bit clean due to the int len argument
  * so the function limits the maximum string size to INT32_MAX (2GB).
  * If the function is called with len == -1 then strlen is called to check
  * the string length is less than INT32_MAX (2GB)
  *
  * Example:
  * @code
 json_object *jobj = NULL;
 const char *mystring = NULL;
 int stringlen = 0;
 enum json_tokener_error jerr;
 do {
     mystring = ...  // get JSON string, e.g. read from file, etc...
     stringlen = strlen(mystring);
     if (end_of_input)
         stringlen++;  // Include the '\0' if we know we're at the end of input
     jobj = json_tokener_parse_ex(tok, mystring, stringlen);
 } while ((jerr = json_tokener_get_error(tok)) == json_tokener_continue);
 if (jerr != json_tokener_success)
 {
     fprintf(stderr, "Error: %s\n", json_tokener_error_desc(jerr));
     // Handle errors, as appropriate for your application.
 }
 if (json_tokener_get_parse_end(tok) < stringlen)
 {
     // Handle extra characters after parsed object as desired.
     // e.g. issue an error, parse another object from that point, etc...
 }
 // Success, use jobj here.
 
 @endcode
  *
  * @param tok a json_tokener previously allocated with json_tokener_new()
  * @param str an string with any valid JSON expression, or portion of.  This does not need to be null terminated.
  * @param len the length of str
  */
 JSON_EXPORT struct json_object *json_tokener_parse_ex(struct json_tokener *tok, const char *str,
                                                       int len);
 
 #ifdef __cplusplus
 }
 #endif
 
 #endif

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