jsondump.c revision 290000 
1#include <stdio.h>
2#include <stdlib.h>
3#include <string.h>
4#include <errno.h>
5#include "../jsmn.h"
6
7/*
8 * An example of reading JSON from stdin and printing its content to stdout.
9 * The output looks like YAML, but I'm not sure if it's really compatible.
10 */
11
12static int dump(const char *js, jsmntok_t *t, size_t count, int indent) {
13	int i, j, k;
14	if (count == 0) {
15		return 0;
16	}
17	if (t->type == JSMN_PRIMITIVE) {
18		printf("%.*s", t->end - t->start, js+t->start);
19		return 1;
20	} else if (t->type == JSMN_STRING) {
21		printf("'%.*s'", t->end - t->start, js+t->start);
22		return 1;
23	} else if (t->type == JSMN_OBJECT) {
24		printf("\n");
25		j = 0;
26		for (i = 0; i < t->size; i++) {
27			for (k = 0; k < indent; k++) printf("  ");
28			j += dump(js, t+1+j, count-j, indent+1);
29			printf(": ");
30			j += dump(js, t+1+j, count-j, indent+1);
31			printf("\n");
32		}
33		return j+1;
34	} else if (t->type == JSMN_ARRAY) {
35		j = 0;
36		printf("\n");
37		for (i = 0; i < t->size; i++) {
38			for (k = 0; k < indent-1; k++) printf("  ");
39			printf("   - ");
40			j += dump(js, t+1+j, count-j, indent+1);
41			printf("\n");
42		}
43		return j+1;
44	}
45	return 0;
46}
47
48int main() {
49	int r;
50	int eof_expected = 0;
51	char *js = NULL;
52	size_t jslen = 0;
53	char buf[BUFSIZ];
54
55	jsmn_parser p;
56	jsmntok_t *tok;
57	size_t tokcount = 2;
58
59	/* Prepare parser */
60	jsmn_init(&p);
61
62	/* Allocate some tokens as a start */
63	tok = malloc(sizeof(*tok) * tokcount);
64	if (tok == NULL) {
65		fprintf(stderr, "malloc(): errno=%d\n", errno);
66		return 3;
67	}
68
69	for (;;) {
70		/* Read another chunk */
71		r = fread(buf, 1, sizeof(buf), stdin);
72		if (r < 0) {
73			fprintf(stderr, "fread(): %d, errno=%d\n", r, errno);
74			return 1;
75		}
76		if (r == 0) {
77			if (eof_expected != 0) {
78				return 0;
79			} else {
80				fprintf(stderr, "fread(): unexpected EOF\n");
81				return 2;
82			}
83		}
84
85		js = realloc(js, jslen + r + 1);
86		if (js == NULL) {
87			fprintf(stderr, "realloc(): errno=%d\n", errno);
88			return 3;
89		}
90		strncpy(js + jslen, buf, r);
91		jslen = jslen + r;
92
93again:
94		r = jsmn_parse(&p, js, jslen, tok, tokcount);
95		if (r < 0) {
96			if (r == JSMN_ERROR_NOMEM) {
97				tokcount = tokcount * 2;
98				tok = realloc(tok, sizeof(*tok) * tokcount);
99				if (tok == NULL) {
100					fprintf(stderr, "realloc(): errno=%d\n", errno);
101					return 3;
102				}
103				goto again;
104			}
105		} else {
106			dump(js, tok, p.toknext, 0);
107			eof_expected = 1;
108		}
109	}
110
111	return 0;
112}
113