Initial commit

.gitignore

+.eggs
+build
+dist
+*.egg-info
+*.sw?
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MANIFEST.in

+include .version

jpssl0util/cli.py

+from datetime import datetime
+
+from jpssl0util import split, dump
+from jpssl0util.timecode import cds_stamp
+
+
+def cmd_split():
+    from argparse import ArgumentParser
+    parser = ArgumentParser()
+    parser.add_argument('--minutes', type=int, default=6)
+    parser.add_argument('--output-format', default='%y%j%H%M%S001.PDS')
+    parser.add_argument('filepath')
+    args = parser.parse_args()
+
+    for time, blob in split.split(args.filepath, args.minutes):
+        stamp = datetime.utcfromtimestamp(time)
+        filepath = stamp.strftime(args.output_format)
+        print("writing %s" % filepath)
+        open(filepath, 'wb', buffering=0).write(blob)
+
+
+def cmd_dump():
+    from argparse import ArgumentParser
+    parser = ArgumentParser()
+    parser.add_argument('pds')
+    args = parser.parse_args()
+
+    def handler(h1, h2):
+        print(h1)
+        if h2:
+            stamp = cds_stamp(h2.day, h2.milliseconds, h2.microseconds)
+            print("\t%s : %s" % (stamp, h2))
+
+    stats = dump.dump(args.pds, handler=handler)
+    print("Packet Count: {:d}".format(stats['packet_count']))
+    print("Group Count: {:d}".format(stats['group_count']))
+    apids = sorted(stats['apid_counts'])
+    for apid in apids:
+        print("APID {:d} Count: {:d}".format(apid, stats['apid_counts'][apid]))

jpssl0util/dump.py

+#!/usr/bin/env python
+from collections import defaultdict
+
+from edos import ccsds
+
+from jpssl0util.timecode import cds_stamp
+
+
+def dump(filepath, handler=None):
+
+    pktcnt = 0
+    groupcnt = 0
+    apidcnts = defaultdict(lambda: 0)
+    for h1, h2 in ccsds.walk(filepath):
+        pktcnt += 1
+        if h1.sequence_grouping == ccsds.GROUP_FIRST:
+            groupcnt += 1
+        apidcnts[h1.apid] += 1
+
+        handler(h1, h2)
+
+    return dict(
+        packet_count = pktcnt,
+        group_count = groupcnt,
+        apid_counts = apidcnts
+    )
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jpssl0util/split.py

+#!/usr/bin/env python
+"""
+
+
+TODO:
+    - Deal with leapseconds, use grain?
+"""
+from io import open
+from cStringIO import StringIO
+from datetime import datetime, timedelta
+
+from edos import ccsds
+
+from jpssl0util.timecode import cds_stamp, unixtime
+
+
+def first_pkt_in_scan(h1):
+    return h1.sequence_grouping == ccsds.GROUP_FIRST
+
+
+def standalone_pkt(h1):
+    return h1.sequence_grouping == ccsds.GROUP_STANDALONE
+
+
+def time_to_roll(time, minutes):
+    return time - time % (minutes * 60)
+
+
+def split(filepath, minutes):
+    """Split a VIIRS L0 PDS file into files based on their scan time mod the
+    number of minutes provided.
+
+    A single output file is buffered in memory until it is written.
+    """
+    with open(filepath, 'rb') as datain:
+
+        buf = StringIO()  # buffer for a single data file until it is written
+        cur_bucket = 0  # cur time bucket of size 'minutes'
+        cursor = 0  # cur pos in file
+        headers = ccsds.walk(filepath)
+
+        for h1, h2 in headers:
+            if first_pkt_in_scan(h1) or standalone_pkt(h1):
+                stamp = cds_stamp(h2.day, h2.millisecods, h2.microseconds)
+                hdrtime = unixtime(stamp)
+
+                pkt_bucket = hdrtime - hdrtime % (minutes * 60)
+                if cur_bucket == 0:
+                    cur_bucket = pkt_bucket
+
+                if cursor != 0 and pkt_bucket > cur_bucket:
+                    yield cur_bucket, buf.getvalue()
+                    buf = StringIO()
+                cur_bucket = pkt_bucket
+
+            datain.seek(cursor)
+            # data_length_minus1 + 1 == len(h2) + len(data)
+            read_size = ccsds.c.sizeof(h1) + h1.data_length_minus1 + 1
+            buf.write(datain.read(read_size))
+            cursor += read_size
+
+        yield cur_bucket, buf.getvalue()
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jpssl0util/timecode.py

+
+from datetime import datetime, timedelta
+
+JPSS_EPOCH = datetime(1958, 1, 1)
+UNIX_EPOCH = datetime(1970, 1, 1)
+
+
+def unixtime(dt):
+    if dt > UNIX_EPOCH:
+        return (dt - UNIX_EPOCH).total_seconds()
+    return (UNIX_EPOCH - dt).total_seconds()
+
+
+def cds_stamp(days, millis, micros, epoch=JPSS_EPOCH):
+    return JPSS_EPOCH + timedelta(days=days, microseconds=1000 * millis + micros)
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setup.py

+from setuptools import setup, find_packages
+
+setup(
+    name='JpssL0Util',
+    version=':pygittools:',
+    pygitmeta=True,
+    packages=find_packages(),
+    setup_requires=[
+        'PyGitTools>=0.1.2'
+    ],
+    install_requires=[
+        'edos'
+    ],
+    entry_points="""
+    [console_scripts]
+    jpssl0split = jpssl0util.cli:cmd_split
+    jpssl0dump = jpssl0util.cli:cmd_dump
+    """
+)
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