Merge pull request #5202 from kaspar030/pkg_add_jsmn

pkg: add jsmn minimal JSON parser

pkg/jsmn/Makefile

@@ -0,0 +1,10 @@
+PKG_NAME=jsmn
+PKG_URL=https://github.com/zserge/jsmn
+PKG_VERSION=b77d84ba48e057aa464b6c6b6f6209e632918cb3
+
+.PHONY: all
+
+all: git-download
+	"$(MAKE)" -C $(PKG_BUILDDIR)
+
+include $(RIOTBASE)/pkg/pkg.mk

pkg/jsmn/Makefile.include

@@ -0,0 +1 @@
+INCLUDES += -I$(BINDIRBASE)/pkg/$(BOARD)/jsmn

tests/pkg_jsmn/Makefile

@@ -0,0 +1,6 @@
+APPLICATION = pkg_jsmn
+include ../Makefile.tests_common
+
+USEPKG += jsmn
+
+include $(RIOTBASE)/Makefile.include

tests/pkg_jsmn/simple.c

@@ -0,0 +1,110 @@
+/*
+ * Copyright (c) 2010 Serge A. Zaitsev
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ *
+ * adapted to RIOT by Kaspar Schleiser <kaspar@schleiser.de>
+ *
+ * changes: - reduced nr of expected tokens to 16, stack would overflow
+ *            otherwise with default stacksize on Cortex-M
+ */
+
+#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.
+ */
+
+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(void)
+{
+    int i;
+    int r;
+    jsmn_parser p;
+    jsmntok_t t[16]; /* We expect no more than 16 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 0;
+}