1 #include <stdio.h>
2 #include <stdlib.h>
3 #include <unistd.h>
4 #include <string.h>
5 #include <errno.h>
6 #include "../jsmn.h"
7
8 /* Function realloc_it() is a wrapper function for standard realloc()
9 * with one difference - it frees old memory pointer in case of realloc
10 * failure. Thus, DO NOT use old data pointer in anyway after call to
11 * realloc_it(). If your code has some kind of fallback algorithm if
12 * memory can't be re-allocated - use standard realloc() instead.
13 */
realloc_it(void * ptrmem,size_t size)14 static inline void *realloc_it(void *ptrmem, size_t size) {
15 void *p = realloc(ptrmem, size);
16 if (!p) {
17 free (ptrmem);
18 fprintf(stderr, "realloc(): errno=%d\n", errno);
19 }
20 return p;
21 }
22
23 /*
24 * An example of reading JSON from stdin and printing its content to stdout.
25 * The output looks like YAML, but I'm not sure if it's really compatible.
26 */
27
dump(const char * js,jsmntok_t * t,size_t count,int indent)28 static int dump(const char *js, jsmntok_t *t, size_t count, int indent) {
29 int i, j, k;
30 if (count == 0) {
31 return 0;
32 }
33 if (t->type == JSMN_PRIMITIVE) {
34 printf("%.*s", t->end - t->start, js+t->start);
35 return 1;
36 } else if (t->type == JSMN_STRING) {
37 printf("'%.*s'", t->end - t->start, js+t->start);
38 return 1;
39 } else if (t->type == JSMN_OBJECT) {
40 printf("\n");
41 j = 0;
42 for (i = 0; i < t->size; i++) {
43 for (k = 0; k < indent; k++) printf(" ");
44 j += dump(js, t+1+j, count-j, indent+1);
45 printf(": ");
46 j += dump(js, t+1+j, count-j, indent+1);
47 printf("\n");
48 }
49 return j+1;
50 } else if (t->type == JSMN_ARRAY) {
51 j = 0;
52 printf("\n");
53 for (i = 0; i < t->size; i++) {
54 for (k = 0; k < indent-1; k++) printf(" ");
55 printf(" - ");
56 j += dump(js, t+1+j, count-j, indent+1);
57 printf("\n");
58 }
59 return j+1;
60 }
61 return 0;
62 }
63
main()64 int main() {
65 int r;
66 int eof_expected = 0;
67 char *js = NULL;
68 size_t jslen = 0;
69 char buf[BUFSIZ];
70
71 jsmn_parser p;
72 jsmntok_t *tok;
73 size_t tokcount = 2;
74
75 /* Prepare parser */
76 jsmn_init(&p);
77
78 /* Allocate some tokens as a start */
79 tok = malloc(sizeof(*tok) * tokcount);
80 if (tok == NULL) {
81 fprintf(stderr, "malloc(): errno=%d\n", errno);
82 return 3;
83 }
84
85 for (;;) {
86 /* Read another chunk */
87 r = fread(buf, 1, sizeof(buf), stdin);
88 if (r < 0) {
89 fprintf(stderr, "fread(): %d, errno=%d\n", r, errno);
90 return 1;
91 }
92 if (r == 0) {
93 if (eof_expected != 0) {
94 return 0;
95 } else {
96 fprintf(stderr, "fread(): unexpected EOF\n");
97 return 2;
98 }
99 }
100
101 js = realloc_it(js, jslen + r + 1);
102 if (js == NULL) {
103 return 3;
104 }
105 strncpy(js + jslen, buf, r);
106 jslen = jslen + r;
107
108 again:
109 r = jsmn_parse(&p, js, jslen, tok, tokcount);
110 if (r < 0) {
111 if (r == JSMN_ERROR_NOMEM) {
112 tokcount = tokcount * 2;
113 tok = realloc_it(tok, sizeof(*tok) * tokcount);
114 if (tok == NULL) {
115 return 3;
116 }
117 goto again;
118 }
119 } else {
120 dump(js, tok, p.toknext, 0);
121 eof_expected = 1;
122 }
123 }
124
125 return EXIT_SUCCESS;
126 }
127