Add trace { endian = big/little; } field

[ctf.git] / common-trace-format-proposal.txt

diff --git a/common-trace-format-proposal.txt b/common-trace-format-proposal.txt
index 6e234350ad4bd779e286532df454864ae32e3009..f2f7e232b4b7b0a23513a74ac24490b8286664ce 100644 (file)
--- a/common-trace-format-proposal.txt
+++ b/common-trace-format-proposal.txt
@@ -582,12 +582,21 @@ Metadata-defined layout (event packet context):
 
 5.1 Event Packet Header Fixed Layout Description
 
 
 5.1 Event Packet Header Fixed Layout Description
 

+The event packet header layout is indicated by the trace packet.header
+field. Here is an example structure type for the packet header with the
+fields typically expected:
+

 struct event_packet_header {
   uint32_t magic;
   uint8_t  trace_uuid[16];
   uint32_t stream_id;
 };
 
 struct event_packet_header {
   uint32_t magic;
   uint8_t  trace_uuid[16];
   uint32_t stream_id;
 };
 

+trace {
+  ...
+  packet.header := struct event_packet_header;
+};
+

 5.2 Event Packet Context Description
 
 Event packet context example. These are declared within the stream declaration
 5.2 Event Packet Context Description
 
 Event packet context example. These are declared within the stream declaration


@@ -879,12 +888,22 @@ readable by accessing the upper dynamic scopes.
 
 The grammar representing the TSDL metadata is presented in Appendix C.
 TSDL Grammar. This section presents a rather ligher reading that
 
 The grammar representing the TSDL metadata is presented in Appendix C.
 TSDL Grammar. This section presents a rather ligher reading that

-consists in examples of TSDL metadata, with template values:
+consists in examples of TSDL metadata, with template values.
+
+Note that the trace endianness is usually extracted from the packet
+header magic number. The "endian" field is only needed when the magic
+number packet header field is not present.

 
 trace {
   major = value;                               /* Trace format version */
   minor = value;
   uuid = "aaaaaaaa-aaaa-aaaa-aaaa-aaaaaaaaaaaa";       /* Trace UUID */
 
 trace {
   major = value;                               /* Trace format version */
   minor = value;
   uuid = "aaaaaaaa-aaaa-aaaa-aaaa-aaaaaaaaaaaa";       /* Trace UUID */

+  endian = big OR little;                      /* Endianness (optional) */
+  packet.header := struct {
+    uint32_t magic;
+    uint8_t  trace_uuid[16];
+    uint32_t stream_id;
+  };

 };
 
 stream {
 };
 
 stream {