Extend inline / fixed length bytes array support (issue #244)

[apps/agl-service-can-low-level.git] / docs / concepts.rst

diff --git a/docs/concepts.rst b/docs/concepts.rst
index b4f657e..2e0d3f9 100644 (file)
--- a/docs/concepts.rst
+++ b/docs/concepts.rst
@@ -148,7 +148,8 @@ Most Protocol Buffers datatypes have directly corresponding C datatypes, such as
 
 1) Strings, bytes and repeated fields of any type map to callback functions by default.
 2) If there is a special option *(nanopb).max_size* specified in the .proto file, string maps to null-terminated char array and bytes map to a structure containing a char array and a size field.
-3) If there is a special option *(nanopb).max_count* specified on a repeated field, it maps to an array of whatever type is being repeated. Another field will be created for the actual number of entries stored.
+3) If *(nanopb).fixed_length* is set to *true* and *(nanopb).max_size* is also set, then bytes map to an inline byte array of fixed size.
+4) If there is a special option *(nanopb).max_count* specified on a repeated field, it maps to an array of whatever type is being repeated. Another field will be created for the actual number of entries stored.
 
 =============================================================================== =======================
       field in .proto                                                           autogenerated in .h
@@ -160,9 +161,10 @@ repeated string name = 1 [(nanopb).max_size = 40, (nanopb).max_count = 5];
                                                                                 | char name[5][40];
 required bytes data = 1 [(nanopb).max_size = 40];                               | typedef struct {
                                                                                 |    size_t size;
-                                                                                |    uint8_t bytes[40];
+                                                                                |    pb_byte_t bytes[40];
                                                                                 | } Person_data_t;
                                                                                 | Person_data_t data;
+required bytes data = 1 [(nanopb).max_size = 40, (nanopb).fixed_length = true]; | pb_byte_t data[40];
 =============================================================================== =======================
 
 The maximum lengths are checked in runtime. If string/bytes/array exceeds the allocated length, *pb_decode* will return false.