Implement generator support for extension fields (no encoder/decoder support yet)

tests/Makefile

@@ -8,7 +8,7 @@ TESTS=  decode_unittests encode_unittests \
 	test_decode_callbacks test_encode_callbacks \
 	test_missing_fields test_no_messages test_funny_name \
 	test_multiple_files test_cxxcompile test_options \
-	bc_encode bc_decode
+	bc_encode bc_decode test_encode_extensions
 
 # More strict checks for the core part of nanopb
 CC_VERSION=$(shell $(CC) -v 2>&1)
@@ -84,6 +84,7 @@ test_no_messages: no_messages.pb.h no_messages.pb.c no_messages.pb.o
 test_funny_name: funny-proto+name.pb.h funny-proto+name.pb.o
 bc_encode: bc_alltypes.pb.o pb_encode.o bc_encode.o
 bc_decode: bc_alltypes.pb.o pb_decode.o bc_decode.o
+test_encode_extensions: test_encode_extensions.c pb_encode.o alltypes.pb.o extensions.pb.o
 
 %.pb: %.proto
 	protoc -I. -I../generator -I/usr/include -o$@ $<
@@ -125,7 +126,7 @@ run_unittests: $(TESTS)
 	./test_encode3_buf 1 | ./test_decode3_buf 1
 	./test_decode3 < alltypes_with_extra_fields.pb
 	./bc_encode | ./bc_decode
-	
+
 	./test_missing_fields
 
 test_options: options.pb.h options.expected options.pb.o

tests/alltypes.proto

@@ -86,5 +86,8 @@ message AllTypes {
     // Just to make sure that the size of the fields has been calculated
     // properly, i.e. otherwise a bug in last field might not be detected.
     required int32      end = 99;
+
+
+    extensions 200 to 255;
 }
 

tests/extensions.proto

@@ -0,0 +1,5 @@
+import 'alltypes.proto';
+
+extend AllTypes {
+    optional int32 AllTypes_extensionfield1 = 255;
+}

tests/test_encode_extensions.c

@@ -0,0 +1,34 @@
+/* Tests extension fields.
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <pb_encode.h>
+#include "alltypes.pb.h"
+#include "extensions.pb.h"
+
+int main(int argc, char **argv)
+{
+    AllTypes alltypes = {0};
+    int32_t extensionfield1 = 12345;
+    pb_extension_t ext1 = {&AllTypes_extensionfield1, &extensionfield1, NULL};
+    
+    alltypes.extensions = &ext1;
+    
+    uint8_t buffer[1024];
+    pb_ostream_t stream = pb_ostream_from_buffer(buffer, sizeof(buffer));
+    
+    /* Now encode it and check if we succeeded. */
+    if (pb_encode(&stream, AllTypes_fields, &alltypes))
+    {
+        fwrite(buffer, 1, stream.bytes_written, stdout);
+        return 0; /* Success */
+    }
+    else
+    {
+        fprintf(stderr, "Encoding failed: %s\n", PB_GET_ERROR(&stream));
+        return 1; /* Failure */
+    }
+}
+