diff --git a/edosl0util/headers.py b/edosl0util/headers.py
index f21c68c893c5c2c1e5efa4033d3026db78d8cb8c..934c1e78d79003022b4f6cdcc870951b50e13627 100644
--- a/edosl0util/headers.py
+++ b/edosl0util/headers.py
@@ -1,29 +1,30 @@
# -*- coding: utf-8 -*-
"""
-CCSDS BaseStruct implementations for AQUA.
+Structures for CCSDS Primary and Secondary headers
See:
- ICD_Space_Ground_Aqua.pdf
- GSFC 422-11-19-03
-
-Last known location:
- http://directreadout.sci.gsfc.nasa.gov/links/rsd_eosdb/PDF/ICD_Space_Ground_Aqua.pdf
+ * ICD_Space_Ground_Aqua.pdf - GSFC 422-11-19-03
+ - http://directreadout.sci.gsfc.nasa.gov/links/rsd_eosdb/PDF/ICD_Space_Ground_Aqua.pdf
+ * CCSDS Space Packet Protocol
+ - http://public.ccsds.org/publications/archive/133x0b1c2.pdf
+ * CCSDS Time Code Formats
+ - http://public.ccsds.org/publications/archive/301x0b4e1.pdf
"""
import ctypes as c
from datetime import datetime, timedelta
-from edos.ccsds import (
- GROUP_FIRST,
- GROUP_LAST,
- GROUP_CONTINUING,
- GROUP_STANDALONE
-)
from edosl0util.timecode import cds_stamp, cds_to_timestamp
+GROUP_FIRST = 0b01
+GROUP_LAST = 0b10
+GROUP_CONTINUING = 0b00
+GROUP_STANDALONE = 0b11
+
+
class BaseStruct(c.BigEndianStructure):
_pack_ = 1
@@ -35,8 +36,25 @@ class BaseStruct(c.BigEndianStructure):
return '<%s (%s)>' % (self.__class__.__name__, fields)
-class Timecode(BaseStruct):
+class PrimaryHeader(BaseStruct):
+ """
+ CCSDS Primary Header.
+ """
+ _fields_ = [
+ ('version_number', c.c_uint8, 3), # == 0
+ ('type_indicator', c.c_uint8, 1),
+ ('secondary_header_flag', c.c_uint8, 1),
+ ('apid', c.c_uint16, 11),
+ ('sequence_grouping', c.c_uint16, 2),
+ ('source_sequence_count', c.c_uint16, 14),
+ ('data_length_minus1', c.c_uint16) # octet count minus one
+ ]
+
+class Timecode(BaseStruct):
+ """
+ Secondary header timecode baseclass.
+ """
def astimestamp(self):
raise NotImplementedError()
@@ -48,13 +66,18 @@ class AquaCucTimecode(Timecode):
"""
EOS AQUA implementation of a CCSDS Unsegmented Timecode. An CUT is an
agency defined timecode which is in this case (I think) specific to Aqua.
+
+ NOTE: I'm betting this will work for Terra as well but I do not have any
+ documentation for Terra.
+
+ FIXME: Not tested or validated!!
"""
_fields_ = [
- ('extension_flag', c.c_uint8, 1), # 1
- ('timecode_epoch', c.c_uint8, 3), # 010 == Jan 1, 1958
- ('coarse_time_count', c.c_uint8, 2), # 11 == 4 octets
- ('fine_time_count', c.c_uint8, 2), # 10 == 2 octets
- ('no_continuation_flag', c.c_uint8, 1), # 0
+ ('extension_flag', c.c_uint8, 1),
+ ('timecode_epoch', c.c_uint8, 3),
+ ('coarse_time_count', c.c_uint8, 2),
+ ('fine_time_count', c.c_uint8, 2),
+ ('no_continuation_flag', c.c_uint8, 1),
('leap_seconds', c.c_uint8, 7),
('seconds', c.c_uint32),
('sub_seconds', c.c_uint16)
@@ -81,6 +104,9 @@ class AquaCucTimecode(Timecode):
class DaySegmentedTimecode(Timecode):
+ """
+ CCSDS Day Segmented Timecode
+ """
_pack_ = 1
_fields_ = [
('days', c.c_uint16),
@@ -98,16 +124,14 @@ class DaySegmentedTimecode(Timecode):
return cds_stamp(self.days, self.milliseconds, self.microseconds)
-class GirdSecondaryHeader(BaseStruct):
- _pack_ = 1
+class AquaGirdSecondaryHeader(BaseStruct):
_fields_ = [
('flags', c.c_uint8),
('timecode', AquaCucTimecode),
]
-class GiisSecondaryHeader(BaseStruct):
- _pack_ = 1
+class AquaGiisSecondaryHeader(BaseStruct):
_fields_ = [
('timecode', DaySegmentedTimecode),
('quicklook_flag', c.c_uint8, 1),
@@ -115,12 +139,42 @@ class GiisSecondaryHeader(BaseStruct):
]
-class SpacecraftBusSecondaryHeader(BaseStruct):
+class AquaSpacecraftBusSecondaryHeader(BaseStruct):
_fields_ = [
('timecode', AquaCucTimecode)
]
+class JpssSecondaryHeader(BaseStruct):
+ """
+ Secondary header using Day Segmented timecodes.
+ """
+ _pack_ = 1
+ _fields_ = [
+ ('timecode', DaySegmentedTimecode)
+ ]
+
+
+class JpssFirstSecondaryHeader(BaseStruct):
+ """
+ Secondary header using Day Segmented timecodes and with a packet count.
+ """
+ _pack_ = 1
+ _fields_ = [
+ ('timecode', DaySegmentedTimecode),
+ ('packet_count', c.c_uint8),
+ ('_spare', c.c_uint8)
+ ]
+
+
+def jpss_header_lookup(primary_header):
+ grouping = primary_header.sequence_grouping
+ if grouping == GROUP_FIRST:
+ return JpssFirstSecondaryHeader
+ elif grouping == GROUP_STANDALONE:
+ return JpssSecondaryHeader
+
+
def amsu_headers():
apids = [
# AMSU-A1
@@ -129,7 +183,7 @@ def amsu_headers():
288, 289, 290
]
flags = [GROUP_FIRST, GROUP_CONTINUING, GROUP_LAST, GROUP_STANDALONE]
- return {(apid, flag): GirdSecondaryHeader
+ return {(apid, flag): AquaGirdSecondaryHeader
for apid in apids
for flag in flags}
@@ -137,32 +191,32 @@ def amsu_headers():
def airs_headers():
return {
# AIRS
- (404, GROUP_STANDALONE): GirdSecondaryHeader,
- (405, GROUP_STANDALONE): GirdSecondaryHeader,
- (406, GROUP_STANDALONE): GirdSecondaryHeader,
- (407, GROUP_STANDALONE): GirdSecondaryHeader,
- (414, GROUP_STANDALONE): GirdSecondaryHeader,
- (415, GROUP_STANDALONE): GirdSecondaryHeader,
- (416, GROUP_STANDALONE): GirdSecondaryHeader,
- (417, GROUP_STANDALONE): GirdSecondaryHeader,
+ (404, GROUP_STANDALONE): AquaGirdSecondaryHeader,
+ (405, GROUP_STANDALONE): AquaGirdSecondaryHeader,
+ (406, GROUP_STANDALONE): AquaGirdSecondaryHeader,
+ (407, GROUP_STANDALONE): AquaGirdSecondaryHeader,
+ (414, GROUP_STANDALONE): AquaGirdSecondaryHeader,
+ (415, GROUP_STANDALONE): AquaGirdSecondaryHeader,
+ (416, GROUP_STANDALONE): AquaGirdSecondaryHeader,
+ (417, GROUP_STANDALONE): AquaGirdSecondaryHeader,
}
def hsb_headers():
return {
# HSB
- (342, GROUP_STANDALONE): GirdSecondaryHeader,
+ (342, GROUP_STANDALONE): AquaGirdSecondaryHeader,
}
def modis_headers():
return {
# MODIS
- (64, GROUP_STANDALONE): GiisSecondaryHeader,
- (64, GROUP_FIRST): GiisSecondaryHeader,
- (64, GROUP_LAST): GiisSecondaryHeader,
- (64, GROUP_CONTINUING): GiisSecondaryHeader,
- (127, GROUP_STANDALONE): GiisSecondaryHeader,
+ (64, GROUP_STANDALONE): AquaGiisSecondaryHeader,
+ (64, GROUP_FIRST): AquaGiisSecondaryHeader,
+ (64, GROUP_LAST): AquaGiisSecondaryHeader,
+ (64, GROUP_CONTINUING): AquaGiisSecondaryHeader,
+ (127, GROUP_STANDALONE): AquaGiisSecondaryHeader,
}
@@ -174,13 +228,13 @@ def ceres_headers():
157, 158, 159, 160
)
groupings = (GROUP_FIRST, GROUP_CONTINUING, GROUP_LAST, GROUP_STANDALONE)
- return {(a, g): GiisSecondaryHeader for a in apids for g in groupings}
+ return {(a, g): AquaGiisSecondaryHeader for a in apids for g in groupings}
def gbad_headers():
return {
# GBAD
- (957, GROUP_STANDALONE): SpacecraftBusSecondaryHeader
+ (957, GROUP_STANDALONE): AquaSpacecraftBusSecondaryHeader
}
@@ -198,38 +252,7 @@ def aqua_headers():
return headers
-class JpssSecondaryHeader(BaseStruct):
- """Secondary Header for a JSPP CCSDS packet that is not part of a packet
- sequence.
- """
- _pack_ = 1
- _fields_ = [
- ('timecode', DaySegmentedTimecode)
- ]
-
-
-class JpssFirstSecondaryHeader(BaseStruct):
- """Secondary Header for a JSPP CCSDS packet that is the first packet in a
- packet sequence. Following packets that are part of this sequence will not
- have a secondary header.
- """
- _pack_ = 1
- _fields_ = [
- ('timecode', DaySegmentedTimecode),
- ('packet_count', c.c_uint8),
- ('_spare', c.c_uint8)
- ]
-
-
-def jpss_header_lookup(primary_header):
- grouping = primary_header.sequence_grouping
- if grouping == GROUP_FIRST:
- return JpssFirstSecondaryHeader
- elif grouping == GROUP_STANDALONE:
- return JpssSecondaryHeader
-
-
-def aqua_header_lookup(primary_header): # noqa
+def aqua_header_lookup(primary_header):
apid = primary_header.apid
grouping = primary_header.sequence_grouping
return _aqua_headers.get((apid, grouping))
diff --git a/edosl0util/stream.py b/edosl0util/stream.py
index a3eab8ecb171b9a495027e41c80fcfbebd1cd7cb..993298caaadc82ad87f19d5639c14b21ba3ce15a 100644
--- a/edosl0util/stream.py
+++ b/edosl0util/stream.py
@@ -1,10 +1,14 @@
import io
import logging
+import ctypes as c
from collections import deque, defaultdict
-from edos.ccsds import (
- c,
+from edosl0util.headers import (
PrimaryHeader,
+ GROUP_FIRST,
+ GROUP_CONTINUING,
+ GROUP_LAST,
+ GROUP_STANDALONE
)
from edosl0util import headers
@@ -19,17 +23,15 @@ def simple_stream(fobj):
"""
Generator that yields PrimaryHeaders and data. Files are read using mmap.
"""
- if fobj is not None:
- data = fobj
psize = c.sizeof(PrimaryHeader)
while True:
- buf = data.read(psize)
+ buf = fobj.read(psize)
if len(buf) < psize:
return
h1 = PrimaryHeader.from_buffer_copy(buf)
# read user data
size = h1.data_length_minus1 + 1
- buf = data.read(size)
+ buf = fobj.read(size)
if len(buf) < size:
return
yield h1, buf
@@ -102,16 +104,16 @@ class Packet(object):
return False
def is_first(self):
- return self.primary_header.sequence_grouping == 0b01
+ return self.primary_header.sequence_grouping == GROUP_FIRST
def is_continuine(self):
- return self.primary_header.sequence_grouping == 0b00
+ return self.primary_header.sequence_grouping == GROUP_CONTINUING
def is_last(self):
- return self.primary_header.sequence_grouping == 0b10
+ return self.primary_header.sequence_grouping == GROUP_LAST
def is_standalone(self):
- return self.primary_header.sequence_grouping == 0b11
+ return self.primary_header.sequence_grouping == GROUP_STANDALONE
class PacketStream(object):