[mirror_iproute2.git] / lib / json_writer.c

/* SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause) */
/*
 * Simple streaming JSON writer
 *
 * This takes care of the annoying bits of JSON syntax like the commas
 * after elements
 *
 * Authors:	Stephen Hemminger <stephen@networkplumber.org>
 */

#include <stdio.h>
#include <stdbool.h>
#include <stdarg.h>
#include <assert.h>
#include <malloc.h>
#include <inttypes.h>
#include <stdint.h>

#include "json_writer.h"

struct json_writer {
	FILE		*out;	/* output file */
	unsigned	depth;  /* nesting */
	bool		pretty; /* optional whitepace */
	char		sep;	/* either nul or comma */
};

/* indentation for pretty print */
static void jsonw_indent(json_writer_t *self)
{
	unsigned i;
	for (i = 0; i < self->depth; ++i)
		fputs("    ", self->out);
}

/* end current line and indent if pretty printing */
static void jsonw_eol(json_writer_t *self)
{
	if (!self->pretty)
		return;

	putc('\n', self->out);
	jsonw_indent(self);
}

/* If current object is not empty print a comma */
static void jsonw_eor(json_writer_t *self)
{
	if (self->sep != '\0')
		putc(self->sep, self->out);
	self->sep = ',';
}


/* Output JSON encoded string */
/* Handles C escapes, does not do Unicode */
static void jsonw_puts(json_writer_t *self, const char *str)
{
	putc('"', self->out);
	for (; *str; ++str)
		switch (*str) {
		case '\t':
			fputs("\\t", self->out);
			break;
		case '\n':
			fputs("\\n", self->out);
			break;
		case '\r':
			fputs("\\r", self->out);
			break;
		case '\f':
			fputs("\\f", self->out);
			break;
		case '\b':
			fputs("\\b", self->out);
			break;
		case '\\':
			fputs("\\n", self->out);
			break;
		case '"':
			fputs("\\\"", self->out);
			break;
		case '\'':
			fputs("\\\'", self->out);
			break;
		default:
			putc(*str, self->out);
		}
	putc('"', self->out);
}

/* Create a new JSON stream */
json_writer_t *jsonw_new(FILE *f)
{
	json_writer_t *self = malloc(sizeof(*self));
	if (self) {
		self->out = f;
		self->depth = 0;
		self->pretty = false;
		self->sep = '\0';
	}
	return self;
}

/* End output to JSON stream */
void jsonw_destroy(json_writer_t **self_p)
{
	json_writer_t *self = *self_p;

	assert(self->depth == 0);
	fputs("\n", self->out);
	fflush(self->out);
	free(self);
	*self_p = NULL;
}

void jsonw_pretty(json_writer_t *self, bool on)
{
	self->pretty = on;
}

/* Basic blocks */
static void jsonw_begin(json_writer_t *self, int c)
{
	jsonw_eor(self);
	putc(c, self->out);
	++self->depth;
	self->sep = '\0';
}

static void jsonw_end(json_writer_t *self, int c)
{
	assert(self->depth > 0);

	--self->depth;
	if (self->sep != '\0')
		jsonw_eol(self);
	putc(c, self->out);
	self->sep = ',';
}


/* Add a JSON property name */
void jsonw_name(json_writer_t *self, const char *name)
{
	jsonw_eor(self);
	jsonw_eol(self);
	self->sep = '\0';
	jsonw_puts(self, name);
	putc(':', self->out);
	if (self->pretty)
		putc(' ', self->out);
}

void jsonw_printf(json_writer_t *self, const char *fmt, ...)
{
	va_list ap;

	va_start(ap, fmt);
	jsonw_eor(self);
	vfprintf(self->out, fmt, ap);
	va_end(ap);
}

/* Collections */
void jsonw_start_object(json_writer_t *self)
{
	jsonw_begin(self, '{');
}

void jsonw_end_object(json_writer_t *self)
{
	jsonw_end(self, '}');
}

void jsonw_start_array(json_writer_t *self)
{
	jsonw_begin(self, '[');
	if (self->pretty)
		putc(' ', self->out);
}

void jsonw_end_array(json_writer_t *self)
{
	if (self->pretty && self->sep)
		putc(' ', self->out);
	self->sep = '\0';
	jsonw_end(self, ']');
}

/* JSON value types */
void jsonw_string(json_writer_t *self, const char *value)
{
	jsonw_eor(self);
	jsonw_puts(self, value);
}

void jsonw_bool(json_writer_t *self, bool val)
{
	jsonw_printf(self, "%s", val ? "true" : "false");
}

void jsonw_null(json_writer_t *self)
{
	jsonw_printf(self, "null");
}

void jsonw_float_fmt(json_writer_t *self, const char *fmt, double num)
{
	jsonw_printf(self, fmt, num);
}

void jsonw_float(json_writer_t *self, double num)
{
	jsonw_printf(self, "%g", num);
}

void jsonw_hu(json_writer_t *self, unsigned short num)
{
	jsonw_printf(self, "%hu", num);
}

void jsonw_uint(json_writer_t *self, uint64_t num)
{
	jsonw_printf(self, "%"PRIu64, num);
}

void jsonw_lluint(json_writer_t *self, unsigned long long int num)
{
	jsonw_printf(self, "%llu", num);
}

void jsonw_int(json_writer_t *self, int64_t num)
{
	jsonw_printf(self, "%"PRId64, num);
}

/* Basic name/value objects */
void jsonw_string_field(json_writer_t *self, const char *prop, const char *val)
{
	jsonw_name(self, prop);
	jsonw_string(self, val);
}

void jsonw_bool_field(json_writer_t *self, const char *prop, bool val)
{
	jsonw_name(self, prop);
	jsonw_bool(self, val);
}

void jsonw_float_field(json_writer_t *self, const char *prop, double val)
{
	jsonw_name(self, prop);
	jsonw_float(self, val);
}

void jsonw_float_field_fmt(json_writer_t *self,
			   const char *prop,
			   const char *fmt,
			   double val)
{
	jsonw_name(self, prop);
	jsonw_float_fmt(self, fmt, val);
}

void jsonw_uint_field(json_writer_t *self, const char *prop, uint64_t num)
{
	jsonw_name(self, prop);
	jsonw_uint(self, num);
}

void jsonw_hu_field(json_writer_t *self, const char *prop, unsigned short num)
{
	jsonw_name(self, prop);
	jsonw_hu(self, num);
}

void jsonw_lluint_field(json_writer_t *self,
			const char *prop,
			unsigned long long int num)
{
	jsonw_name(self, prop);
	jsonw_lluint(self, num);
}

void jsonw_int_field(json_writer_t *self, const char *prop, int64_t num)
{
	jsonw_name(self, prop);
	jsonw_int(self, num);
}

void jsonw_null_field(json_writer_t *self, const char *prop)
{
	jsonw_name(self, prop);
	jsonw_null(self);
}

#ifdef TEST
int main(int argc, char **argv)
{
	json_writer_t *wr = jsonw_new(stdout);

	jsonw_start_object(wr);
	jsonw_pretty(wr, true);
	jsonw_name(wr, "Vyatta");
	jsonw_start_object(wr);
	jsonw_string_field(wr, "url", "http://vyatta.com");
	jsonw_uint_field(wr, "downloads", 2000000ul);
	jsonw_float_field(wr, "stock", 8.16);

	jsonw_name(wr, "ARGV");
	jsonw_start_array(wr);
	while (--argc)
		jsonw_string(wr, *++argv);
	jsonw_end_array(wr);

	jsonw_name(wr, "empty");
	jsonw_start_array(wr);
	jsonw_end_array(wr);

	jsonw_name(wr, "NIL");
	jsonw_start_object(wr);
	jsonw_end_object(wr);

	jsonw_null_field(wr, "my_null");

	jsonw_name(wr, "special chars");
	jsonw_start_array(wr);
	jsonw_string_field(wr, "slash", "/");
	jsonw_string_field(wr, "newline", "\n");
	jsonw_string_field(wr, "tab", "\t");
	jsonw_string_field(wr, "ff", "\f");
	jsonw_string_field(wr, "quote", "\"");
	jsonw_string_field(wr, "tick", "\'");
	jsonw_string_field(wr, "backslash", "\\");
	jsonw_end_array(wr);

	jsonw_end_object(wr);

	jsonw_end_object(wr);
	jsonw_destroy(&wr);
	return 0;
}

#endif
Commit	Line	Data
d9d8c839	1	/* SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause) */
fcc16c22 SH	2	/*
	3	* Simple streaming JSON writer
	4	*
	5	* This takes care of the annoying bits of JSON syntax like the commas
	6	* after elements
	7	*
fcc16c22 SH	8	* Authors: Stephen Hemminger <stephen@networkplumber.org>
	9	*/
	10
	11	#include <stdio.h>
	12	#include <stdbool.h>
	13	#include <stdarg.h>
	14	#include <assert.h>
	15	#include <malloc.h>
	16	#include <inttypes.h>
	17	#include <stdint.h>
	18
	19	#include "json_writer.h"
	20
	21	struct json_writer {
	22	FILE out; / output file */
	23	unsigned depth; /* nesting */
	24	bool pretty; /* optional whitepace */
	25	char sep; /* either nul or comma */
	26	};
	27
	28	/* indentation for pretty print */
	29	static void jsonw_indent(json_writer_t *self)
	30	{
	31	unsigned i;
d721a145	32	for (i = 0; i < self->depth; ++i)
fcc16c22 SH	33	fputs(" ", self->out);
	34	}
	35
	36	/* end current line and indent if pretty printing */
	37	static void jsonw_eol(json_writer_t *self)
	38	{
	39	if (!self->pretty)
	40	return;
	41
	42	putc('\n', self->out);
	43	jsonw_indent(self);
	44	}
	45
	46	/* If current object is not empty print a comma */
	47	static void jsonw_eor(json_writer_t *self)
	48	{
	49	if (self->sep != '\0')
	50	putc(self->sep, self->out);
	51	self->sep = ',';
	52	}
	53
	54
	55	/* Output JSON encoded string */
	56	/* Handles C escapes, does not do Unicode */
	57	static void jsonw_puts(json_writer_t self, const char str)
	58	{
	59	putc('"', self->out);
	60	for (; *str; ++str)
	61	switch (*str) {
	62	case '\t':
	63	fputs("\\t", self->out);
	64	break;
	65	case '\n':
	66	fputs("\\n", self->out);
	67	break;
	68	case '\r':
	69	fputs("\\r", self->out);
	70	break;
	71	case '\f':
	72	fputs("\\f", self->out);
	73	break;
	74	case '\b':
	75	fputs("\\b", self->out);
	76	break;
	77	case '\\':
	78	fputs("\\n", self->out);
	79	break;
	80	case '"':
	81	fputs("\\\"", self->out);
	82	break;
	83	case '\'':
	84	fputs("\\\'", self->out);
	85	break;
	86	default:
	87	putc(*str, self->out);
	88	}
	89	putc('"', self->out);
	90	}
	91
	92	/* Create a new JSON stream */
	93	json_writer_t jsonw_new(FILE f)
	94	{
	95	json_writer_t self = malloc(sizeof(self));
	96	if (self) {
97	self->out = f;
98	self->depth = 0;
99	self->pretty = false;
100	self->sep = '\0';
fcc16c22 SH	101	}
	102	return self;
	103	}
	104
	105	/* End output to JSON stream */
	106	void jsonw_destroy(json_writer_t **self_p)
	107	{
	108	json_writer_t self = self_p;
	109
	110	assert(self->depth == 0);
d721a145	111	fputs("\n", self->out);
fcc16c22 SH	112	fflush(self->out);
	113	free(self);
	114	*self_p = NULL;
	115	}
	116
	117	void jsonw_pretty(json_writer_t *self, bool on)
	118	{
	119	self->pretty = on;
	120	}
	121
	122	/* Basic blocks */
	123	static void jsonw_begin(json_writer_t *self, int c)
	124	{
	125	jsonw_eor(self);
	126	putc(c, self->out);
	127	++self->depth;
	128	self->sep = '\0';
	129	}
	130
	131	static void jsonw_end(json_writer_t *self, int c)
	132	{
	133	assert(self->depth > 0);
	134
	135	--self->depth;
	136	if (self->sep != '\0')
	137	jsonw_eol(self);
	138	putc(c, self->out);
	139	self->sep = ',';
	140	}
	141
	142
	143	/* Add a JSON property name */
	144	void jsonw_name(json_writer_t self, const char name)
	145	{
	146	jsonw_eor(self);
	147	jsonw_eol(self);
	148	self->sep = '\0';
	149	jsonw_puts(self, name);
	150	putc(':', self->out);
	151	if (self->pretty)
	152	putc(' ', self->out);
	153	}
	154
7252f16b	155	void jsonw_printf(json_writer_t self, const char fmt, ...)
fcc16c22 SH	156	{
	157	va_list ap;
	158
	159	va_start(ap, fmt);
	160	jsonw_eor(self);
	161	vfprintf(self->out, fmt, ap);
	162	va_end(ap);
	163	}
	164
	165	/* Collections */
	166	void jsonw_start_object(json_writer_t *self)
	167	{
	168	jsonw_begin(self, '{');
	169	}
	170
	171	void jsonw_end_object(json_writer_t *self)
	172	{
	173	jsonw_end(self, '}');
	174	}
	175
	176	void jsonw_start_array(json_writer_t *self)
	177	{
	178	jsonw_begin(self, '[');
6cbd9465 SH	179	if (self->pretty)
6cbd9465 SH	180	putc(' ', self->out);
fcc16c22 SH	181	}
	182
	183	void jsonw_end_array(json_writer_t *self)
	184	{
6cbd9465 SH	185	if (self->pretty && self->sep)
	186	putc(' ', self->out);
	187	self->sep = '\0';
fcc16c22 SH	188	jsonw_end(self, ']');
	189	}
	190
	191	/* JSON value types */
	192	void jsonw_string(json_writer_t self, const char value)
	193	{
	194	jsonw_eor(self);
	195	jsonw_puts(self, value);
	196	}
	197
	198	void jsonw_bool(json_writer_t *self, bool val)
	199	{
	200	jsonw_printf(self, "%s", val ? "true" : "false");
	201	}
	202
fcc16c22 SH	203	void jsonw_null(json_writer_t *self)
	204	{
	205	jsonw_printf(self, "null");
	206	}
	207
7252f16b JF	208	void jsonw_float_fmt(json_writer_t self, const char fmt, double num)
	209	{
	210	jsonw_printf(self, fmt, num);
	211	}
	212
fcc16c22 SH	213	void jsonw_float(json_writer_t *self, double num)
	214	{
	215	jsonw_printf(self, "%g", num);
	216	}
fcc16c22	217
7252f16b JF	218	void jsonw_hu(json_writer_t *self, unsigned short num)
	219	{
	220	jsonw_printf(self, "%hu", num);
	221	}
	222
fcc16c22 SH	223	void jsonw_uint(json_writer_t *self, uint64_t num)
	224	{
	225	jsonw_printf(self, "%"PRIu64, num);
	226	}
	227
7252f16b JF	228	void jsonw_lluint(json_writer_t *self, unsigned long long int num)
	229	{
	230	jsonw_printf(self, "%llu", num);
	231	}
	232
fcc16c22 SH	233	void jsonw_int(json_writer_t *self, int64_t num)
	234	{
	235	jsonw_printf(self, "%"PRId64, num);
	236	}
	237
	238	/* Basic name/value objects */
	239	void jsonw_string_field(json_writer_t self, const char prop, const char *val)
	240	{
	241	jsonw_name(self, prop);
	242	jsonw_string(self, val);
	243	}
	244
	245	void jsonw_bool_field(json_writer_t self, const char prop, bool val)
	246	{
	247	jsonw_name(self, prop);
	248	jsonw_bool(self, val);
	249	}
	250
fcc16c22 SH	251	void jsonw_float_field(json_writer_t self, const char prop, double val)
	252	{
	253	jsonw_name(self, prop);
	254	jsonw_float(self, val);
	255	}
fcc16c22	256
7252f16b JF	257	void jsonw_float_field_fmt(json_writer_t *self,
	258	const char *prop,
	259	const char *fmt,
	260	double val)
	261	{
	262	jsonw_name(self, prop);
	263	jsonw_float_fmt(self, fmt, val);
	264	}
	265
fcc16c22 SH	266	void jsonw_uint_field(json_writer_t self, const char prop, uint64_t num)
	267	{
	268	jsonw_name(self, prop);
	269	jsonw_uint(self, num);
	270	}
	271
7252f16b JF	272	void jsonw_hu_field(json_writer_t self, const char prop, unsigned short num)
	273	{
	274	jsonw_name(self, prop);
	275	jsonw_hu(self, num);
	276	}
	277
	278	void jsonw_lluint_field(json_writer_t *self,
	279	const char *prop,
	280	unsigned long long int num)
	281	{
	282	jsonw_name(self, prop);
	283	jsonw_lluint(self, num);
	284	}
	285
fcc16c22 SH	286	void jsonw_int_field(json_writer_t self, const char prop, int64_t num)
	287	{
	288	jsonw_name(self, prop);
	289	jsonw_int(self, num);
	290	}
	291
fcc16c22 SH	292	void jsonw_null_field(json_writer_t self, const char prop)
	293	{
	294	jsonw_name(self, prop);
	295	jsonw_null(self);
	296	}
fcc16c22 SH	297
	298	#ifdef TEST
	299	int main(int argc, char **argv)
	300	{
	301	json_writer_t *wr = jsonw_new(stdout);
	302
d721a145	303	jsonw_start_object(wr);
fcc16c22 SH	304	jsonw_pretty(wr, true);
	305	jsonw_name(wr, "Vyatta");
	306	jsonw_start_object(wr);
	307	jsonw_string_field(wr, "url", "http://vyatta.com");
	308	jsonw_uint_field(wr, "downloads", 2000000ul);
	309	jsonw_float_field(wr, "stock", 8.16);
	310
	311	jsonw_name(wr, "ARGV");
	312	jsonw_start_array(wr);
	313	while (--argc)
	314	jsonw_string(wr, *++argv);
	315	jsonw_end_array(wr);
	316
	317	jsonw_name(wr, "empty");
	318	jsonw_start_array(wr);
	319	jsonw_end_array(wr);
	320
	321	jsonw_name(wr, "NIL");
	322	jsonw_start_object(wr);
	323	jsonw_end_object(wr);
	324
	325	jsonw_null_field(wr, "my_null");
	326
	327	jsonw_name(wr, "special chars");
	328	jsonw_start_array(wr);
	329	jsonw_string_field(wr, "slash", "/");
	330	jsonw_string_field(wr, "newline", "\n");
	331	jsonw_string_field(wr, "tab", "\t");
	332	jsonw_string_field(wr, "ff", "\f");
	333	jsonw_string_field(wr, "quote", "\"");
	334	jsonw_string_field(wr, "tick", "\'");
	335	jsonw_string_field(wr, "backslash", "\\");
	336	jsonw_end_array(wr);
	337
	338	jsonw_end_object(wr);
	339
d721a145	340	jsonw_end_object(wr);
fcc16c22 SH	341	jsonw_destroy(&wr);
	342	return 0;
	343	}
	344
	345	#endif