Interface to YAJL's JSON stream parsing facilities. More...

#include "yajl_common.h"

Include dependency graph for yajl_parse.h:

Classes
struct	yajl_callbacks

Typedefs
typedef struct yajl_handle_t *	yajl_handle

Enumerations
enum	yajl_status { yajl_status_ok, yajl_status_client_canceled, yajl_status_error }

enum	yajl_option { yajl_allow_comments = 0x01, yajl_dont_validate_strings = 0x02, yajl_allow_trailing_garbage = 0x04, yajl_allow_multiple_values = 0x08, yajl_allow_partial_values = 0x10, yajl_allow_json5 = 0x20 }

Functions
YAJL_API const char *	yajl_status_to_string (yajl_status code)

YAJL_API yajl_handle	yajl_alloc (const yajl_callbacks callbacks, yajl_alloc_funcs afs, void *ctx)

YAJL_API int	yajl_config (yajl_handle hand, int option,...)

YAJL_API void	yajl_free (yajl_handle hand)

YAJL_API yajl_status	yajl_parse (yajl_handle hand, const unsigned char *jsonText, size_t jsonTextLength)

YAJL_API yajl_status	yajl_complete_parse (yajl_handle hand)

YAJL_API unsigned char *	yajl_get_error (yajl_handle hand, int verbose, const unsigned char *jsonText, size_t jsonTextLength)

YAJL_API size_t	yajl_get_bytes_consumed (yajl_handle hand)

YAJL_API void	yajl_free_error (yajl_handle hand, unsigned char *str)

Detailed Description

Author: Lloyd Hilaiel

Definition in file yajl_parse.h.

Typedef Documentation

typedef struct yajl_handle_t* yajl_handle

An opaque handle to a parser.

Definition at line 46 of file yajl_parse.h.

Enumeration Type Documentation

enum yajl_status

Error codes returned from this interface.

Enumerator
yajl_status_ok	No error was encountered.
yajl_status_client_canceled	A client callback returned zero, stopping the parse.
yajl_status_error	An error occured during the parse. Call yajl_get_error() for more information about the encountered error.

Definition at line 32 of file yajl_parse.h.

enum yajl_option

Configuration parameters for the parser. These should be passed to yajl_config() followed by any option specific argument(s). In general, all boolean configuration parameters default to off.

Enumerator
yajl_allow_comments	Ignore javascript style comments present in the input. These are not standard in JSON but can be enabled with this. Turning on the yajl_allow_json5 option enables this option automatically. yajl_config() argument type: int (boolean) Example: yajl_config(h, yajl_allow_comments, 1); // turn comment support on
yajl_dont_validate_strings	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 the processor and compiler in use) yajl_config() argument type: int (boolean) Example: yajl_config(h, yajl_dont_validate_strings, 1); // disable utf8 checking
yajl_allow_trailing_garbage	By default, upon calls to yajl_complete_parse(), yajl will ensure the entire input text was consumed and will raise an error otherwise. Turning this flag on causes YAJL to disable the garbage check. This can be useful when parsing JSON out of an input stream that contains more than a single JSON document. yajl_config() argument type: int (boolean) Example: yajl_config(h, yajl_allow_trailing_garbage, 1); // non-JSON follows
yajl_allow_multiple_values	Allow multiple values to be parsed by a single handle. The entire text must be valid JSON, and values can be separated by any kind of whitespace. This flag will change the behavior of the parser, and cause it to 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_config() argument type: int (boolean) Example: yajl_config(h, yajl_allow_multiple_values, 1); // multi-doc stream
yajl_allow_partial_values	When yajl_complete_parse() is called the parser will check that the top level value was completely consumed. 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_config() argument type: int (boolean) Example: yajl_config(h, yajl_allow_partial_values, 1); // might stop early
yajl_allow_json5	The JSON5 standard allows additional formats for numbers, strings and object keys which are not permitted by the JSON standard. Setting this flag tells yajl to accept JSON5 standard input. This flag also enables `yajl_allow_comments` since comments are part of the JSON5 standard. In the EPICS build this option is enabled by default, it must be turned off to disable JSON5. yajl_config() argument type: int (boolean) Example: yajl_config(h, yajl_allow_json5, 1); // We accept JSON5!

Definition at line 112 of file yajl_parse.h.

Function Documentation

YAJL_API const char* yajl_status_to_string ( yajl_status code )

Return a human readable, English, string for an error.

YAJL_API yajl_handle yajl_alloc	(	const yajl_callbacks *	callbacks,
		yajl_alloc_funcs *	afs,
		void *	ctx
	)

Allocate a parser handle.

Parameters

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.
afs	Memory allocation functions, pass `NULL` to use the C runtime library routines (malloc() and friends).
ctx	A context pointer that will be passed to callbacks.

YAJL_API int yajl_config	(	yajl_handle	hand,
		int	option,
			...
	)

Set parser options associated with a parser handle. See the yajl_option documentation for details of the available options and their arguments.

Returns: Zero in case of error, non-zero otherwise.

YAJL_API void yajl_free ( yajl_handle hand )

Free a parser handle.

YAJL_API yajl_status yajl_parse	(	yajl_handle	hand,
		const unsigned char *	jsonText,
		size_t	jsonTextLength
	)

Parse some json!

Parameters

hand	A handle to the json parser allocated with yajl_alloc().
jsonText	A pointer to the UTF8 json text to be parsed.
jsonTextLength	The length, in bytes, of input text.

YAJL_API yajl_status yajl_complete_parse ( yajl_handle hand )

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 received, yajl can't know whether another digit is next or some character that would terminate the integer token.

Parameters

hand	a handle to the json parser allocated with yajl_alloc().

YAJL_API unsigned char* yajl_get_error	(	yajl_handle	hand,
		int	verbose,
		const unsigned char *	jsonText,
		size_t	jsonTextLength
	)

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 size_t yajl_get_bytes_consumed ( yajl_handle hand )

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 void yajl_free_error	(	yajl_handle	hand,
		unsigned char *	str
	)

Free an error string returned from yajl_get_error().

Classes

Typedefs

Enumerations

Functions

Detailed Description

Typedef Documentation

Enumeration Type Documentation

Function Documentation