gp_json_reader.h File Reference

A JSON parser. More...

#include <stdio.h>
#include <core/gp_compiler.h>
#include <utils/gp_json_common.h>

Go to the source code of this file.

Data Structures
struct	gp_json_reader
	A JSON parser internal state. More...
struct	gp_json_val
	A parsed JSON key value pair. More...
struct	gp_json_obj_attr
	A JSON object attribute description i.e. key and type. More...
struct	gp_json_obj
	A JSON object description. More...
struct	gp_json_state
	A JSON parser state. More...

Typedefs
typedef struct gp_json_val	gp_json_val
	A parsed JSON key value pair.
typedef struct gp_json_obj_attr	gp_json_obj_attr
	A JSON object attribute description i.e. key and type.
typedef struct gp_json_obj	gp_json_obj
	A JSON object description.
typedef struct gp_json_state	gp_json_state
	A JSON parser state.

Functions
gp_json_val *	gp_json_val_alloc (size_t buf_size)
	Allocates a JSON value.
void	gp_json_val_free (gp_json_val *self)
	Frees a JSON value.
const char *	gp_json_type_name (enum gp_json_type type)
	Returns type name.
void	gp_json_err (gp_json_reader *self, const char *fmt,...)
	Fills the reader error.
void	gp_json_err_print (gp_json_reader *self)
	Prints error stored in the buffer.
void	gp_json_warn (gp_json_reader *self, const char *fmt,...)
	Prints a warning.
static int	gp_json_reader_err (gp_json_reader *self)
	Returns true if error was encountered.
static int	gp_json_valid (struct gp_json_val *res)
	Checks is result has valid type.
enum gp_json_type	gp_json_next_type (gp_json_reader *self)
	Returns the type of next element in buffer.
enum gp_json_type	gp_json_start (gp_json_reader *self)
	Returns if first element in JSON is object or array.
int	gp_json_obj_first (gp_json_reader *self, struct gp_json_val *res)
	Starts parsing of an JSON object.
size_t	gp_json_lookup (const void *arr, size_t memb_size, size_t list_len, const char *key)
	Utility function for log(n) lookup in a sorted array.
int	gp_json_obj_first_filter (gp_json_reader *self, struct gp_json_val *res, const struct gp_json_obj *obj, const struct gp_json_obj *ign)
	Object parsing functions with with attribute list.
int	gp_json_obj_skip (gp_json_reader *self)
	Skips parsing of an JSON object.
int	gp_json_arr_skip (gp_json_reader *self)
	Skips parsing of an JSON array.
static struct gp_json_state	gp_json_state_start (gp_json_reader *self)
	Returns a parser state at the start of current object/array.
static void	gp_json_state_load (gp_json_reader *self, struct gp_json_state state)
	Returns the parser to a saved state.
static void	gp_json_reset (gp_json_reader *self)
	Resets the parser to a start.
gp_json_reader *	gp_json_reader_load (const char *path)
	Loads a file into an gp_json_reader buffer.
void	gp_json_reader_free (gp_json_reader *self)
	Frees an gp_json_reader buffer.
void	gp_json_reader_finish (gp_json_reader *self)
	Prints errors and warnings at the end of parsing.
static int	gp_json_empty (gp_json_reader *self)
	Returns non-zero if whole buffer has been consumed.

Detailed Description

A JSON parser.

Definition in file gp_json_reader.h.

Function Documentation

gp_json_arr_skip()

int gp_json_arr_skip

(

gp_json_reader *

self

)

Skips parsing of an JSON array.

Parameters

self	A gp_json_reader

Returns

Zero on success, non-zero otherwise.

gp_json_empty()

static int gp_json_empty ( gp_json_reader *  self )

inlinestatic

Returns non-zero if whole buffer has been consumed.

Parameters

self	A gp_json_reader.

Returns

Non-zero if whole buffer was consumed.

Definition at line 354 of file gp_json_reader.h.

References gp_json_reader::len, and gp_json_reader::off.

gp_json_err()

void gp_json_err	(	gp_json_reader *	self,
		const char *	fmt,
			...
	)

Fills the reader error.

Once buffer error is set all parsing functions return immediatelly with type set to GP_JSON_VOID.

Parameters

self	An gp_json_reader
fmt	A printf like format string
...	A printf like parameters

gp_json_err_print()

void gp_json_err_print

(

gp_json_reader *

self

)

Prints error stored in the buffer.

The error takes into consideration the current offset in the buffer and prints a few preceding lines along with the exact position of the error.

The error is passed to the err_print() handler.

Parameters

self	A gp_json_reader

gp_json_lookup()

size_t gp_json_lookup	(	const void *	arr,
		size_t	memb_size,
		size_t	list_len,
		const char *	key
	)

Utility function for log(n) lookup in a sorted array.

Parameters

list	Analphabetically sorted array.
list_len	Array length.

Returns

An array index or (size_t)-1 if key wasn't found.

gp_json_next_type()

enum gp_json_type gp_json_next_type

(

gp_json_reader *

self

)

Returns the type of next element in buffer.

Parameters

self	A gp_json_reader

Returns

A type of next element in the buffer.

gp_json_obj_first()

int gp_json_obj_first	(	gp_json_reader *	self,
		struct gp_json_val *	res
	)

Starts parsing of an JSON object.

Parameters

self	A gp_json_reader @res An gp_json result.

gp_json_obj_first_filter()

int gp_json_obj_first_filter	(	gp_json_reader *	self,
		struct gp_json_val *	res,
		const struct gp_json_obj *	obj,
		const struct gp_json_obj *	ign
	)

Object parsing functions with with attribute list.

These functions allows you to efficiently filter a set of keys for a given object passed in gp_json_obj.

Parameters

self	A gp_json_reader
res	An gp_json result.
obj	An gp_json_obj object description.
f	A file to print warnings to.

gp_json_obj_skip()

int gp_json_obj_skip

(

gp_json_reader *

self

)

Skips parsing of an JSON object.

Parameters

self	A gp_json_reader

Returns

Zero on success, non-zero otherwise.

gp_json_reader_err()

static int gp_json_reader_err ( gp_json_reader *  self )

inlinestatic

Returns true if error was encountered.

Parameters

self	A gp_json_reader

Returns

True if error was encountered false otherwise.

Definition at line 146 of file gp_json_reader.h.

gp_json_reader_finish()

void gp_json_reader_finish

(

gp_json_reader *

self

)

Prints errors and warnings at the end of parsing.

Checks if self->err is set and prints the error with gp_json_reader_err()

Checks if there is any text left after the parser has finished and prints a warning if so.

Parameters

self	A gp_json_reader

gp_json_reader_free()

void gp_json_reader_free

(

gp_json_reader *

self

)

Frees an gp_json_reader buffer.

Parameters

self	A gp_json_reader allocated by gp_json_load() function.

gp_json_reader_load()

gp_json_reader * gp_json_reader_load

(

const char *

path

)

Loads a file into an gp_json_reader buffer.

The reader has to be later freed by gp_json_reader_free().

Parameters

path	A path to a file.

Returns

A gp_json_reader or NULL in a case of a failure.

gp_json_reset()

static void gp_json_reset ( gp_json_reader *  self )

inlinestatic

Resets the parser to a start.

Parameters

self	A gp_json_reader

Definition at line 311 of file gp_json_reader.h.

References gp_json_reader::depth, gp_json_reader::off, and gp_json_reader::sub_off.

gp_json_start()

enum gp_json_type gp_json_start

(

gp_json_reader *

self

)

Returns if first element in JSON is object or array.

Parameters

self	A gp_json_reader

Returns

On success returns GP_JSON_OBJ or GP_JSON_ARR. On failure GP_JSON_VOID.

gp_json_state_load()

static void gp_json_state_load ( gp_json_reader *  self, struct gp_json_state  state  )

inlinestatic

Returns the parser to a saved state.

This function could be used for the parser to return to the start of object or array saved by t the gp_json_state_get() function.

Parameters

self	A gp_json_reader
state	An parser state as returned by the gp_json_state_get().

Definition at line 299 of file gp_json_reader.h.

References gp_json_reader::depth, gp_json_reader::off, and gp_json_reader::sub_off.

gp_json_state_start()

static struct gp_json_state gp_json_state_start ( gp_json_reader *  self )

inlinestatic

Returns a parser state at the start of current object/array.

This function could be used for the parser to return to the start of the currently parsed object or array.

Parameters

self	A gp_json_reader

Returns

A state that points to a start of the last object or array.

Definition at line 280 of file gp_json_reader.h.

gp_json_type_name()

const char * gp_json_type_name

(

enum gp_json_type

type

)

Returns type name.

Parameters

type	A json type.

Returns

A type name.

gp_json_val_alloc()

gp_json_val * gp_json_val_alloc

(

size_t

buf_size

)

Allocates a JSON value.

Parameters

buf_size

A maximal buffer size for a string value, pass 0 for default.

Returns

A newly allocated JSON value.

gp_json_val_free()

void gp_json_val_free

(

gp_json_val *

self

)

Frees a JSON value.

Parameters

self	A JSON value previously allocated by gp_json_val_alloc().

gp_json_valid()

static int gp_json_valid ( struct gp_json_val *  res )

inlinestatic

Checks is result has valid type.

Parameters

res	An gp_json value.

Returns

Zero if result is not valid, non-zero otherwise.

Definition at line 157 of file gp_json_reader.h.

gp_json_warn()

void gp_json_warn	(	gp_json_reader *	self,
		const char *	fmt,
			...
	)

Prints a warning.

Uses the print handler in the buffer to print a warning along with a few lines of context from the JSON at the current position.

Parameters

self	A gp_json_reader
fmt	A printf-like error string.
...	A printf-like parameters.