use uint8_t instead of char for serialized message (#161)

* use uint8_t instead of char for serialized message

* fix typo

* fix windows waning

rmw/include/rmw/serialized_message.h

@@ -20,19 +20,19 @@ extern "C"
 {
 #endif
 
-#include "rcutils/types/char_array.h"
+#include "rcutils/types/uint8_array.h"
 
-// aliases for rcutils_char_array_t
+// aliases for rcutils_uint8_array_t
 /*
- * For now this is a simple aliasing from a serialized message to a char array.
+ * For now this is a simple aliasing from a serialized message to a uint8 array.
  * However, in future developments this serialized message can become something
  * more complex and is therefore aliased.
  */
-typedef rcutils_char_array_t rmw_serialized_message_t;
-#define rmw_get_zero_initialized_serialized_message rcutils_get_zero_initialized_char_array
-#define rmw_serialized_message_init rcutils_char_array_init
-#define rmw_serialized_message_fini rcutils_char_array_fini
-#define rmw_serialized_message_resize rcutils_char_array_resize
+typedef rcutils_uint8_array_t rmw_serialized_message_t;
+#define rmw_get_zero_initialized_serialized_message rcutils_get_zero_initialized_uint8_array
+#define rmw_serialized_message_init rcutils_uint8_array_init
+#define rmw_serialized_message_fini rcutils_uint8_array_fini
+#define rmw_serialized_message_resize rcutils_uint8_array_resize
 
 #if __cplusplus
 }

rmw/test/test_serialized_message.cpp

@@ -35,26 +35,36 @@ TEST(test_serialized_message, resize) {
   auto ret = rmw_serialized_message_init(&serialized_msg, 5, &allocator);
   ASSERT_EQ(RMW_RET_OK, ret);
 
-  memcpy(serialized_msg.buffer, "1234\0", 5);
+  for (size_t i = 0; i < 5; ++i) {
+    uint8_t c = 1u << i;
+    memcpy(serialized_msg.buffer + i, &c, 1);
+  }
   serialized_msg.buffer_length = 5;
-  EXPECT_STREQ("1234\0", serialized_msg.buffer);
+  for (size_t i = 0; i < serialized_msg.buffer_length; ++i) {
+    EXPECT_EQ(1u << i, serialized_msg.buffer[i]);
+  }
 
   ret = rmw_serialized_message_resize(&serialized_msg, 11);
   ASSERT_EQ(RMW_RET_OK, ret);
   EXPECT_EQ(11u, serialized_msg.buffer_capacity);
   EXPECT_EQ(5u, serialized_msg.buffer_length);
 
-  memcpy(serialized_msg.buffer, "0987654321\0", 11);
+  for (size_t i = 0; i < 11; ++i) {
+    uint8_t c = 0xFF - static_cast<uint8_t>(i);
+    memcpy(serialized_msg.buffer + i, &c, 1);
+  }
   serialized_msg.buffer_length = 11;
-  EXPECT_STREQ("0987654321\0", serialized_msg.buffer);
+  for (size_t i = 0; i < 11; ++i) {
+    EXPECT_EQ(0xFF - i, serialized_msg.buffer[i]);
+  }
 
   ret = rmw_serialized_message_resize(&serialized_msg, 3);
   ASSERT_EQ(RMW_RET_OK, ret);
   EXPECT_EQ(3u, serialized_msg.buffer_capacity);
   EXPECT_EQ(3u, serialized_msg.buffer_length);
-  EXPECT_EQ('0', serialized_msg.buffer[0]);
-  EXPECT_EQ('9', serialized_msg.buffer[1]);
-  EXPECT_EQ('8', serialized_msg.buffer[2]);
+  EXPECT_EQ(0xFF, serialized_msg.buffer[0]);
+  EXPECT_EQ(0xFF - 1, serialized_msg.buffer[1]);
+  EXPECT_EQ(0xFF - 2, serialized_msg.buffer[2]);
   // the other fields are garbage.
 
   // cleanup only 3 fields