Tests for callback fields

git-svn-id: https://svn.kapsi.fi/jpa/nanopb@974 e3a754e5-d11d-0410-8d38-ebb782a927b9

tests/test_decode_callbacks.c

@@ -0,0 +1,44 @@
+/* Decoding testcase for callback fields.
+ * Run e.g. ./test_encode_callbacks | ./test_decode_callbacks
+ */
+
+#include <stdio.h>
+#include <pb_decode.h>
+#include "callbacks.pb.h"
+
+bool print_string(pb_istream_t *stream, const pb_field_t *field, void *arg)
+{
+    uint8_t buffer[1024];
+    
+    /* We could read block-by-block to avoid the large buffer... */
+    if (stream->bytes_left > sizeof(buffer))
+        return false;
+    
+    if (!pb_read(stream, buffer, stream->bytes_left))
+        return false;
+    
+    /* Print the string, in format comparable with protoc --decode. */
+    printf("%s: \"%s\"\n", (char*)arg, buffer);
+    return true;
+}
+
+int main()
+{
+    uint8_t buffer[1024];
+    size_t length = fread(buffer, 1, 1024, stdin);
+    pb_istream_t stream = pb_istream_from_buffer(buffer, length);
+    
+    /* Note: empty initializer list initializes the struct with all-0.
+     * This is recommended so that unused callbacks are set to NULL instead
+     * of crashing at runtime.
+     */
+    TestMessage testmessage = {};
+    
+    testmessage.stringvalue.funcs.decode = &print_string;
+    testmessage.stringvalue.arg = "stringvalue";
+    
+    if (!pb_decode(&stream, TestMessage_fields, &testmessage))
+        return 1;
+    
+    return 0;
+}