begin cleaning up mesh library layer so that it could be split someday

src/mesh/mesh-pb-constants.h

@@ -0,0 +1,27 @@
+#pragma once
+
+#include "mesh.pb.h"
+
+// this file defines constants which come from mesh.options
+
+// Tricky macro to let you find the sizeof a type member
+#define member_size(type, member) sizeof(((type *)0)->member)
+
+/// max number of packets which can be waiting for delivery to android - note, this value comes from mesh.options protobuf
+#define MAX_RX_TOPHONE (member_size(DeviceState, receive_queue) / member_size(DeviceState, receive_queue[0]))
+
+/// max number of nodes allowed in the mesh
+#define MAX_NUM_NODES (member_size(DeviceState, node_db) / member_size(DeviceState, node_db[0]))
+
+/// helper function for encoding a record as a protobuf, any failures to encode are fatal and we will panic
+/// returns the encoded packet size
+size_t pb_encode_to_bytes(uint8_t *destbuf, size_t destbufsize, const pb_msgdesc_t *fields, const void *src_struct);
+
+/// helper function for decoding a record as a protobuf, we will return false if the decoding failed
+bool pb_decode_from_bytes(const uint8_t *srcbuf, size_t srcbufsize, const pb_msgdesc_t *fields, void *dest_struct);
+
+/// Read from an Arduino File
+bool readcb(pb_istream_t *stream, uint8_t *buf, size_t count);
+
+/// Write to an arduino file
+bool writecb(pb_ostream_t *stream, const uint8_t *buf, size_t count);