src/lib/jsmn/example/jsondump.c

   1 #include <stdio.h>
   2 #include <stdlib.h>
   3 #include <string.h>
   4 #include <errno.h>
   5 #include "../jsmn.c"
   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
  12 static 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
  48 int main() {
  49         int r;
  50         int eof_expected = 0;
  51         char *js = NULL;
  52         size_t jslen = 0;
  53         char buf[BUFSIZ-256];
  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
  93 again:
  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 }