From f6f9140043c93c4ec32d07a813aad10aae1b44e3 Mon Sep 17 00:00:00 2001
From: Sven Gestegard Robertz <sven.robertz@cs.lth.se>
Date: Fri, 20 Feb 2015 10:53:18 +0100
Subject: [PATCH] comparison with Avro on hierarchical typedefs
---
doc/tech_report.tex | 57 +++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 57 insertions(+)
diff --git a/doc/tech_report.tex b/doc/tech_report.tex
index e0ae1d6..651076d 100644
--- a/doc/tech_report.tex
+++ b/doc/tech_report.tex
@@ -666,6 +666,63 @@ LabComm assumes that, while the transport may drop packets, there will
be no bit errors in a received packet. If data integrity is required,
that is delegated to the reader and writer for the particular transport.
+\subsubsection{Representation of hierarchical data types}
+
+For a type that contains fields of other user types, like
+\begin{verbatim}
+typedef struct {
+ int x;
+ int y;
+} Point;
+
+sample struct {
+ Point start;
+ Point end;
+} line;
+\end{verbatim}
+
+LabComm encodes both the flattened signature and the
+typedef which allows the hierarchical type structure to be
+reconstructed.
+%
+The avro encoding is quite similar.
+The \verb+Line+ example, corresponds to the two schemas
+\begin{verbatim}
+{"namespace": "example.avro",
+ "type": "record",
+ "name": "Point",
+ "fields": [
+ {"name": "x", "type": "int"},
+ {"name": "y", "type": "int"}
+ ]
+}
+\end{verbatim}
+and
+\begin{verbatim}
+{"namespace": "example.avro",
+ "type": "record",
+ "name": "Line",
+ "fields": [
+ {"name": "start", "type": "Point"},
+ {"name": "end", "type": "Point"}
+ ]
+}
+\end{verbatim}
+which is encoded in an Object Container File as
+\begin{verbatim}
+{"type":"record",
+ "name":"Line",
+ "namespace":"example.avro",
+ "fields":[{"name":"start",
+ "type":{"type":"record",
+ "name":"Point",
+ "fields":[{"name":"x","type":"int"},
+ {"name":"y","type":"int"}]}},
+ {"name":"end",
+ "type":"Point"}
+ ]
+}
+\end{verbatim}
\subsubsection{Fetures not in LabComm}
Avro has a set of features with no counterpart in LabComm. They include
--
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