https://github.com/olemorud/json-parser
JSON parser in C
https://github.com/olemorud/json-parser
c json json-parser
Last synced: about 2 months ago
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JSON parser in C
- Host: GitHub
- URL: https://github.com/olemorud/json-parser
- Owner: olemorud
- License: gpl-3.0
- Created: 2023-04-24T15:14:17.000Z (about 2 years ago)
- Default Branch: master
- Last Pushed: 2023-06-05T20:37:29.000Z (almost 2 years ago)
- Last Synced: 2025-02-09T02:34:44.623Z (4 months ago)
- Topics: c, json, json-parser
- Language: C
- Homepage:
- Size: 3.63 MB
- Stars: 0
- Watchers: 1
- Forks: 0
- Open Issues: 0
-
Metadata Files:
- Readme: README.md
- License: COPYING
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README
# C JSON Parser
Just a simple project to practice writing parsers.
Not guaranteed to be safe, reliable or efficient.
## Usage
### Compile
build (release build):
```sh
make BUILD=release
```
To make a debug build just run `make`.
### Run
```sh
./bin/release/json_parser sample-files/large-file.json
```
## Implementation
Parsed JSON values are stored as structs containing type information and data.
```c
enum json_type { object, array, string, number, boolean, null };
struct json_value {
enum json_type type;
union {
obj_t* object;
struct json_value** array;
char* string;
bool boolean;
double number;
};
};
```
### Types
#### JSON Objects
Object values have the type field set to `(enum json_type) object`
They are stored using a poorly written map implementation with the type `obj_t`
in `json_value.object`
See [obj_t](#obj_t) for more details.
#### JSON Arrays
Array values have the type field set to `(enum json_type) array`
JSON Arrays are stored as null-terminated `json_value*` arrays,
i.e. `struct json_value**`, in `json_value.array`
#### JSON Numbers
Number values have the type field set to `(enum json_type) number`
Numbers are stored as `double` values in `json_value.number`
(The JSON specification doesn't strictly specify a maximum value,
but `double` is sufficient for parsing almost all JSON data.)
#### JSON Strings
Strings have the type field set to `(enum json_type) string`
Strings are stored as null-terminated char arrays, `char*`, in `json_value.string`
#### JSON Booleans
Boolean values have the type field set to `(enum json_type) boolean`
The values are stored as `bool` in `json_value.boolean`
#### JSON Null
Null values have type field set to `(enum json_type) null`.
### obj\_t
`obj_t` is defined in `json_value.h` as:
```c
typedef struct obj_entry {
char const* key;
struct json_value* val;
struct obj_entry* next;
} * __p_obj_entry;
typedef __p_obj_entry obj_t[OBJ_SIZE]; // OBJ_SIZE=1024
```
#### obj\_t methods
`void* obj_at(obj_t m, char* key)`
Returns a pointer to a value for the given key.
`bool obj_insert(obj_t m, char* const key, struct json_value* value)`
Insert a key-value pair
`void obj_delete(obj_t m)`
Recursively free memory allocated for object and children objects.