code: plan9front

ref: ad1ab7089d9f046080450e59724bef2c98fc8f5a
dir: /sys/src/libjson/printjson.c/

#include <u.h>
#include <libc.h>
#include <json.h>

static int printjson(Fmt*, JSON*, int);
static int printarray(Fmt*, JSON*, int);
static int printobject(Fmt*, JSON*, int);

static int
printarray(Fmt *f, JSON *j, int indent)
{
	JSONEl *jl;
	int i, r;

	if(j->first == nil){
		return fmtprint(f, "[]");
	}
	r = fmtprint(f, "[\n");
	for(jl = j->first; jl != nil; jl = jl->next){
		for(i = 0; i < indent; i++)
			r += fmtprint(f, "\t");
		r += printjson(f, jl->val, indent);
		r += fmtprint(f, "%s\n", jl->next != nil ? "," : "");
	}
	for(i = 0; i < indent-1; i++)
		r += fmtprint(f, "\t");
	r += fmtprint(f, "]");
	return r;
}

static int
printobject(Fmt *f, JSON *j, int indent)
{
	JSONEl *jl;
	int i, r;

	if(j->first == nil){
		return fmtprint(f, "{}");
	}
	r = fmtprint(f, "{\n");
	for(jl = j->first; jl != nil; jl = jl->next){
		for(i = 0; i < indent; i++)
			fmtprint(f, "\t");
		r += fmtprint(f, "\"%s\": ", jl->name);
		r += printjson(f, jl->val, indent);
		r += fmtprint(f, "%s\n", jl->next != nil ? "," : "");
	}
	for(i = 0; i < indent-1; i++)
		r += fmtprint(f, "\t");
	r += fmtprint(f, "}");
	return r;
}

static int
printjson(Fmt *f, JSON *j, int indent)
{
	switch(j->t){
	case JSONNull:
		return fmtprint(f, "null");
		break;
	case JSONBool:
		return fmtprint(f, "%s", j->n ? "true" : "false");
		break;
	case JSONNumber:
		return fmtprint(f, "%f", j->n);
		break;
	case JSONString:
		return fmtprint(f, "\"%s\"", j->s);
		break;
	case JSONArray:
		return printarray(f, j, indent+1);
		break;
	case JSONObject:
		return printobject(f, j, indent+1);
		break;
	}
	return 0;
}

int
JSONfmt(Fmt *f)
{
	JSON *j;

	j = va_arg(f->args, JSON*);
	return printjson(f, j, 0);
}

void
JSONfmtinstall(void)
{
	fmtinstall('J', JSONfmt);
}