Project restructuring (fixes macOS builds) (#198)

- Create `Include/` folder for all main projects
- Fix some issues here and there (found while moving things)
- All includes are now in `Tactility/` subfolder and must be included with that prefix. This fixes issues with clashing POSIX headers (e.g. `<semaphore.h>` versus Tactility's `Semaphore.h`)

TactilityC/Include/tt_message_queue.h

@@ -0,0 +1,63 @@
+#pragma once
+
+#include <freertos/FreeRTOS.h>
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#include <stdint.h>
+#include <stdbool.h>
+
+/** A handle that represents a message queue instance */
+typedef void* MessageQueueHandle;
+
+/**
+ * Allocate a new message queue in memory.
+ * @param[in] capacity how many messages this queue can contain before it starts blocking input
+ * @param[in] messageSize the size of a message
+ */
+MessageQueueHandle tt_message_queue_alloc(uint32_t capacity, uint32_t messageSize);
+
+/** Free up the memory of a queue (dealloc) */
+void tt_message_queue_free(MessageQueueHandle handle);
+
+/**
+ * Put (post) a message in the queue
+ * @param[in] handle the queue handle
+ * @param[in] message the message of the correct size - its data will be copied
+ * @param[timeout] timeout the amount of ticks to wait until the message is queued
+ * @return true if the item was successfully queued
+ */
+bool tt_message_queue_put(MessageQueueHandle handle, const void* message, TickType_t timeout);
+
+/**
+ * Get the oldest message from the queue.
+ * @param[in] handle the queue handle
+ * @param[out] message a pointer to a message of the correct size
+ * @param[in] timeout the amount of ticks to wait until a message was copied
+ * @return true if a message was successfully copied
+ */
+bool tt_message_queue_get(MessageQueueHandle handle, void* message, TickType_t timeout);
+
+/** @return the total amount of messages that this queue can hold */
+uint32_t tt_message_queue_get_capacity(MessageQueueHandle handle);
+
+/** @return the size of a single message in the queue */
+uint32_t tt_message_queue_get_message_size(MessageQueueHandle handle);
+
+/** @return the current amount of items in the queue */
+uint32_t tt_message_queue_get_count(MessageQueueHandle handle);
+
+/** @return the remaining capacity in the queue */
+uint32_t tt_message_queue_get_space(MessageQueueHandle handle);
+
+/**
+ * Remove all items from the queue (if any)
+ * @return true on failure
+ */
+bool tt_message_queue_reset(MessageQueueHandle handle);
+
+#ifdef __cplusplus
+}
+#endif