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# Relaxed Streaming JSON Parser C Library
## Differences from RFC 4627
* unquoted keys
* single quotes `'`
* `//` and `/* */` style comments
* extra commas `,` in arrays and objects
## Why?
[Official JSON](http://json.org/) is *almost* human-readable and
human-writable. If we disable a few of the strict rules, we can make it
significantly more so.
You would use this library when parsing user input, such as a config file.
You would *not* use this library when serializing or deserializing, or
as a format for computer-to-computer communication.
I could not find another JSON parser that fit all of these requirements:
* C library
* Relaxed parsing rules as outlined above. As a rule of thumb the parser
should be compatible with [GYP](https://code.google.com/p/gyp/).
* Streaming - ability to not buffer the entire JSON string in memory
before parsing it.
* In Debian/Ubuntu's package repository or at least scheduled to be in it.
So I wrote one that satisfies all these requirements. It has a
[test suite](test) and is already in use by
[another project](https://github.com/andrewrk/rucksack). It has been uploaded
to Debian and is scheduled to be released in "jessie" and Ubuntu 14.10
Utopic Unicorn.
## Usage
See include/laxjson.h for more details.
```c
#include <laxjson.h>
#include <stdio.h>
static int on_string(struct LaxJsonContext *context,
enum LaxJsonType type, const char *value, int length)
{
const char *type_name = type == LaxJsonTypeProperty ? "property" : "string";
printf("%s: %s\n", type_name, value);
return 0;
}
static int on_number(struct LaxJsonContext *context, double x) {
printf("number: %f\n", x);
return 0;
}
static int on_primitive(struct LaxJsonContext *context, enum LaxJsonType type) {
const char *type_name;
if (type == LaxJsonTypeTrue)
type_name = "true";
else if (type == LaxJsonTypeFalse)
type_name = "false";
else
type_name = "null";
printf("primitive: %s\n", type_name);
return 0;
}
static int on_begin(struct LaxJsonContext *context, enum LaxJsonType type) {
const char *type_name = (type == LaxJsonTypeArray) ? "array" : "object";
printf("begin %s\n", type_name);
return 0;
}
static int on_end(struct LaxJsonContext *context, enum LaxJsonType type) {
const char *type_name = (type == LaxJsonTypeArray) ? "array" : "object";
printf("end %s\n", type_name);
return 0;
}
int main() {
char buf[1024];
struct LaxJsonContext *context;
FILE *f;
int amt_read;
enum LaxJsonError err;
context = lax_json_create();
context->userdata = NULL; /* can set this to whatever you want */
context->string = on_string;
context->number = on_number;
context->primitive = on_primitive;
context->begin = on_begin;
context->end = on_end;
f = fopen("file.json", "rb");
while ((amt_read = fread(buf, 1, sizeof(buf), f))) {
if ((err = lax_json_feed(context, amt_read, buf))) {
fprintf(stderr, "Line %d, column %d: %s\n",
context->line, context->column, lax_json_str_err(err));
return -1;
}
lax_json_feed(context, amt_read, buf);
}
if ((err = lax_json_eof(context))) {
fprintf(stderr, "Line %d, column %d: %s\n",
context->line, context->column, lax_json_str_err(err));
return -1;
}
lax_json_destroy(context);
return 0;
}
```
## Installation
### Pre-Built Packages
* [Ubuntu PPA](https://launchpad.net/~andrewrk/+archive/rucksack)
```
sudo apt-add-repository ppa:andrewrk/rucksack
sudo apt-get update
sudo apt-get install liblaxjson-dev
```
### From Source
```sh
mkdir build
cd build
cmake ..
make
sudo make install
```
To run the tests, use `make test`.
## Projects Using liblaxjson
Feel free to make a pull request adding to this list.
* [rucksack](https://github.com/andrewrk/rucksack) - a texture packer and
resource bundler
* [Genesis](https://github.com/andrewrk/genesis) - digital audio workstation
* [lua-laxjson](https://github.com/sjnam/lua-laxjson) - Lua bindings
|
