Allow decoding of escaped forward slashes

src/mjson.c

@@ -318,6 +318,13 @@ static int mjson_unescape(const char *s, int len, char *to, int n) {
       if (s[i + 2] != '0' || s[i + 3] != '0') return -1;  // Too much, give up
       ((unsigned char *) to)[j] = mjson_unhex_nimble(s + i + 4);
       i += 5;
+    } else if (s[i] == '\\' && i + 1 < len && s[i + 1] == '/') {
+      // Any character may be escaped in a string. This takes care of escaped
+      // slashes only to minimize added complexity while supporting PHP's
+      // default json encoding format, as that escapes forward slashes by
+      // default.
+      to[j] = '/';
+      i++;
     } else if (s[i] == '\\' && i + 1 < len) {
       int c = mjson_esc(s[i + 1], 0);
       if (c == 0) return -1;

test/unit_test.c

@@ -340,6 +340,13 @@ static void test_get_string(void) {
     ASSERT(mjson_get_string(s, (int) strlen(s), "$[2]", buf, sizeof(buf)) > 0);
     ASSERT(strcmp(buf, expected) == 0);
   }
+
+  {
+    const char *s = "{\"url\":\"https:\\/\\/example.org\\/\"}";
+    const char *expected = "https://example.org/";
+    ASSERT(mjson_get_string(s, (int) strlen(s), "$.url", buf, sizeof(buf)) == 20);
+    ASSERT(strcmp(buf, expected) == 0);
+  }
 }
 
 static void test_print(void) {