1 files changed, 76 insertions, 0 deletions
diff --git a/example/simple.c b/example/simple.c
new file mode 100644
index 0000000..aeb9cf4
--- /dev/null
+++ b/example/simple.c
@@ -0,0 +1,76 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include "../jsmn.h"
+
+/*
+ * A small example of jsmn parsing when JSON structure is known and number of
+ * tokens is predictable.
+ */
+
+static const char *JSON_STRING =
+	"{\"user\": \"johndoe\", \"admin\": false, \"uid\": 1000,\n  "
+	"\"groups\": [\"users\", \"wheel\", \"audio\", \"video\"]}";
+
+static int jsoneq(const char *json, jsmntok_t *tok, const char *s) {
+	if (tok->type == JSMN_STRING && (int) strlen(s) == tok->end - tok->start &&
+			strncmp(json + tok->start, s, tok->end - tok->start) == 0) {
+		return 0;
+	}
+	return -1;
+}
+
+int main() {
+	int i;
+	int r;
+	jsmn_parser p;
+	jsmntok_t t[128]; /* We expect no more than 128 tokens */
+
+	jsmn_init(&p);
+	r = jsmn_parse(&p, JSON_STRING, strlen(JSON_STRING), t, sizeof(t)/sizeof(t[0]));
+	if (r < 0) {
+		printf("Failed to parse JSON: %d\n", r);
+		return 1;
+	}
+
+	/* Assume the top-level element is an object */
+	if (r < 1 || t[0].type != JSMN_OBJECT) {
+		printf("Object expected\n");
+		return 1;
+	}
+
+	/* Loop over all keys of the root object */
+	for (i = 1; i < r; i++) {
+		if (jsoneq(JSON_STRING, &t[i], "user") == 0) {
+			/* We may use strndup() to fetch string value */
+			printf("- User: %.*s\n", t[i+1].end-t[i+1].start,
+					JSON_STRING + t[i+1].start);
+			i++;
+		} else if (jsoneq(JSON_STRING, &t[i], "admin") == 0) {
+			/* We may additionally check if the value is either "true" or "false" */
+			printf("- Admin: %.*s\n", t[i+1].end-t[i+1].start,
+					JSON_STRING + t[i+1].start);
+			i++;
+		} else if (jsoneq(JSON_STRING, &t[i], "uid") == 0) {
+			/* We may want to do strtol() here to get numeric value */
+			printf("- UID: %.*s\n", t[i+1].end-t[i+1].start,
+					JSON_STRING + t[i+1].start);
+			i++;
+		} else if (jsoneq(JSON_STRING, &t[i], "groups") == 0) {
+			int j;
+			printf("- Groups:\n");
+			if (t[i+1].type != JSMN_ARRAY) {
+				continue; /* We expect groups to be an array of strings */
+			}
+			for (j = 0; j < t[i+1].size; j++) {
+				jsmntok_t *g = &t[i+j+2];
+				printf("  * %.*s\n", g->end - g->start, JSON_STRING + g->start);
+			}
+			i += t[i+1].size + 1;
+		} else {
+			printf("Unexpected key: %.*s\n", t[i].end-t[i].start,
+					JSON_STRING + t[i].start);
+		}
+	}
+	return EXIT_SUCCESS;
+}