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/*
* Copyright (c) 2007-2011, Lloyd Hilaiel <lloyd@hilaiel.com>
*
* Permission to use, copy, modify, and/or distribute this software for any
* purpose with or without fee is hereby granted, provided that the above
* copyright notice and this permission notice appear in all copies.
*
* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
*/
/**
* \file yajl_parse.h
* Interface to YAJL's JSON stream parsing facilities.
*/
#include <yajl/yajl_common.h>
#ifndef __YAJL_PARSE_H__
#define __YAJL_PARSE_H__
#include <stddef.h>
#ifdef __cplusplus
extern "C" {
#endif
/** error codes returned from this interface */
typedef enum {
/** no error was encountered */
yajl_status_ok,
/** a client callback returned zero, stopping the parse */
yajl_status_client_canceled,
/** An error occured during the parse. Call yajl_get_error for
* more information about the encountered error */
yajl_status_error
} yajl_status;
/** attain a human readable, english, string for an error */
YAJL_API const char * yajl_status_to_string(yajl_status code);
/** an opaque handle to a parser */
typedef struct yajl_handle_t * yajl_handle;
/** yajl is an event driven parser. this means as json elements are
* parsed, you are called back to do something with the data. The
* functions in this table indicate the various events for which
* you will be called back. Each callback accepts a "context"
* pointer, this is a void * that is passed into the yajl_parse
* function which the client code may use to pass around context.
*
* All callbacks return an integer. If non-zero, the parse will
* continue. If zero, the parse will be canceled and
* yajl_status_client_canceled will be returned from the parse.
*
* \attention {
* A note about the handling of numbers:
*
* yajl will only convert numbers that can be represented in a
* double or a 64 bit (long long) int. All other numbers will
* be passed to the client in string form using the yajl_number
* callback. Furthermore, if yajl_number is not NULL, it will
* always be used to return numbers, that is yajl_integer and
* yajl_double will be ignored. If yajl_number is NULL but one
* of yajl_integer or yajl_double are defined, parsing of a
* number larger than is representable in a double or 64 bit
* integer will result in a parse error.
* }
*/
typedef struct {
int (* yajl_null)(void * ctx);
int (* yajl_boolean)(void * ctx, int boolVal);
int (* yajl_integer)(void * ctx, long long integerVal);
int (* yajl_double)(void * ctx, double doubleVal);
/** A callback which passes the string representation of the number
* back to the client. Will be used for all numbers when present */
int (* yajl_number)(void * ctx, const char * numberVal,
size_t numberLen);
/** strings are returned as pointers into the JSON text when,
* possible, as a result, they are _not_ null padded */
int (* yajl_string)(void * ctx, const unsigned char * stringVal,
size_t stringLen);
int (* yajl_start_map)(void * ctx);
int (* yajl_map_key)(void * ctx, const unsigned char * key,
size_t stringLen);
int (* yajl_end_map)(void * ctx);
int (* yajl_start_array)(void * ctx);
int (* yajl_end_array)(void * ctx);
} yajl_callbacks;
/** allocate a parser handle
* \param callbacks a yajl callbacks structure specifying the
* functions to call when different JSON entities
* are encountered in the input text. May be NULL,
* which is only useful for validation.
* \param afs memory allocation functions, may be NULL for to use
* C runtime library routines (malloc and friends)
* \param ctx a context pointer that will be passed to callbacks.
*/
YAJL_API yajl_handle yajl_alloc(const yajl_callbacks * callbacks,
yajl_alloc_funcs * afs,
void * ctx);
/** configuration parameters for the parser, these may be passed to
* yajl_config() along with option specific argument(s). In general,
* all configuration parameters default to *off*. */
typedef enum {
/** Ignore javascript style comments present in
* JSON input. Non-standard, but rather fun
* arguments: toggled off with integer zero, on otherwise.
*
* example:
* yajl_config(h, yajl_allow_comments, 1); // turn comment support on
*/
yajl_allow_comments = 0x01,
/**
* When set the parser will verify that all strings in JSON input are
* valid UTF8 and will emit a parse error if this is not so. When set,
* this option makes parsing slightly more expensive (~7% depending
* on processor and compiler in use)
*
* example:
* yajl_config(h, yajl_dont_validate_strings, 1); // disable utf8 checking
*/
yajl_dont_validate_strings = 0x02,
/**
* By default, upon calls to yajl_complete_parse(), yajl will
* ensure the entire input text was consumed and will raise an error
* otherwise. Enabling this flag will cause yajl to disable this
* check. This can be useful when parsing json out of a that contains more
* than a single JSON document.
*/
yajl_allow_trailing_garbage = 0x04,
/**
* Allow multiple values to be parsed by a single handle. The
* entire text must be valid JSON, and values can be seperated
* by any kind of whitespace. This flag will change the
* behavior of the parser, and cause it continue parsing after
* a value is parsed, rather than transitioning into a
* complete state. This option can be useful when parsing multiple
* values from an input stream.
*/
yajl_allow_multiple_values = 0x08,
/**
* When yajl_complete_parse() is called the parser will
* check that the top level value was completely consumed. I.E.,
* if called whilst in the middle of parsing a value
* yajl will enter an error state (premature EOF). Setting this
* flag suppresses that check and the corresponding error.
*/
yajl_allow_partial_values = 0x10
} yajl_option;
/** allow the modification of parser options subsequent to handle
* allocation (via yajl_alloc)
* \returns zero in case of errors, non-zero otherwise
*/
YAJL_API int yajl_config(yajl_handle h, yajl_option opt, ...);
/** free a parser handle */
YAJL_API void yajl_free(yajl_handle handle);
/** Parse some json!
* \param hand - a handle to the json parser allocated with yajl_alloc
* \param jsonText - a pointer to the UTF8 json text to be parsed
* \param jsonTextLength - the length, in bytes, of input text
*/
YAJL_API yajl_status yajl_parse(yajl_handle hand,
const unsigned char * jsonText,
size_t jsonTextLength);
/** Parse any remaining buffered json.
* Since yajl is a stream-based parser, without an explicit end of
* input, yajl sometimes can't decide if content at the end of the
* stream is valid or not. For example, if "1" has been fed in,
* yajl can't know whether another digit is next or some character
* that would terminate the integer token.
*
* \param hand - a handle to the json parser allocated with yajl_alloc
*/
YAJL_API yajl_status yajl_complete_parse(yajl_handle hand);
/** get an error string describing the state of the
* parse.
*
* If verbose is non-zero, the message will include the JSON
* text where the error occured, along with an arrow pointing to
* the specific char.
*
* \returns A dynamically allocated string will be returned which should
* be freed with yajl_free_error
*/
YAJL_API unsigned char * yajl_get_error(yajl_handle hand, int verbose,
const unsigned char * jsonText,
size_t jsonTextLength);
/**
* get the amount of data consumed from the last chunk passed to YAJL.
*
* In the case of a successful parse this can help you understand if
* the entire buffer was consumed (which will allow you to handle
* "junk at end of input").
*
* In the event an error is encountered during parsing, this function
* affords the client a way to get the offset into the most recent
* chunk where the error occured. 0 will be returned if no error
* was encountered.
*/
YAJL_API size_t yajl_get_bytes_consumed(yajl_handle hand);
/** free an error returned from yajl_get_error */
YAJL_API void yajl_free_error(yajl_handle hand, unsigned char * str);
#ifdef __cplusplus
}
#endif
#endif
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