X-Git-Url: https://gerrit.automotivelinux.org/gerrit/gitweb?a=blobdiff_plain;f=docs%2Findex.rst;h=1022a1b278f82b7d1dfb985a9b6be87786033d0b;hb=b2a696795e0f79e6913b79c6a8e840ce4cd44d25;hp=93f04c6ca346b58c1f7da5b9ec41562409fb8099;hpb=2cefaeaf61f38f1566293e53b4708e9ceff2d945;p=apps%2Flow-level-can-service.git

diff --git a/docs/index.rst b/docs/index.rst
index 93f04c6..1022a1b 100644
--- a/docs/index.rst
+++ b/docs/index.rst
@@ -21,10 +21,10 @@ So a typical project might include these files:
 
 1) Nanopb runtime library:
     - pb.h
-    - pb_decode.h and pb_decode.c
-    - pb_encode.h and pb_encode.c
+    - pb_decode.h and pb_decode.c (needed for decoding messages)
+    - pb_encode.h and pb_encode.c (needed for encoding messages)
 2) Protocol description (you can have many):
-    - person.proto
+    - person.proto (just an example)
     - person.c (autogenerated, contains initializers for const arrays)
     - person.h (autogenerated, contains type declarations)
 
@@ -42,11 +42,14 @@ Features and limitations
 
 **Limitations**
 
-#) User must provide callbacks when decoding arrays or strings without maximum size.
+#) User must provide callbacks when decoding arrays or strings without maximum size. Malloc support could be added as a separate module.
 #) Some speed has been sacrificed for code size. For example varint calculations are always done in 64 bits.
 #) Encoding is focused on writing to streams. For memory buffers only it could be made more efficient.
 #) The deprecated Protocol Buffers feature called "groups" is not supported.
 #) Fields in the generated structs are ordered by the tag number, instead of the natural ordering in .proto file.
+#) Unknown fields are not preserved when decoding and re-encoding a message.
+#) Numeric arrays are always encoded as packed, even if not marked as packed in .proto. This causes incompatibility with decoders that do not support packed format.
+#) Cyclic references between messages are not supported. They could be supported in callback-mode if there was an option in the generator to set the mode.
 
 Getting started
 ===============
@@ -57,12 +60,12 @@ For starters, consider this simple message::
     required int32 value = 1;
  }
 
-Save this in *example.proto* and compile it::
+Save this in *message.proto* and compile it::
 
     user@host:~$ protoc -omessage.pb message.proto
-    user@host:~$ python ../generator/nanopb_generator.py message.pb
+    user@host:~$ python nanopb/generator/nanopb_generator.py message.pb
 
-You should now have in *example.h*::
+You should now have in *message.pb.h*::
 
  typedef struct {
     int32_t value;
@@ -79,7 +82,26 @@ Now in your main program do this to encode a message::
 
 After that, buffer will contain the encoded message.
 The number of bytes in the message is stored in *stream.bytes_written*.
-You can feed the message to *protoc --decode=Example example.proto* to verify its validity.
+You can feed the message to *protoc --decode=Example message.proto* to verify its validity.
+
+For complete examples of the simple cases, see *tests/test_decode1.c* and *tests/test_encode1.c*. For an example with network interface, see the *example* subdirectory.
+
+Compiler requirements
+=====================
+Nanopb should compile with most ansi-C compatible compilers. It however requires a few header files to be available:
+
+#) *string.h*, with these functions: *strlen*, *memcpy*, *memset*
+#) *stdint.h*, for definitions of *int32_t* etc.
+#) *stddef.h*, for definition of *size_t*
+#) *stdbool.h*, for definition of *bool*
+
+If these header files do not come with your compiler, you should be able to find suitable replacements online. Mostly the requirements are very simple, just a few basic functions and typedefs.
+
+Debugging and testing
+=====================
+Extensive unittests are included under the *tests* folder. Just type *make* there to run the tests.
+
+This also generates a file called *breakpoints* which includes all lines returning *false* in nanopb. You can use this in gdb by typing *source breakpoints*, after which gdb will break on first nanopb error.
 
 Wishlist
 ========