def read_mpef(file_name):
s = Segment(file_name)
if s.file_type == 144:
return s
else:
raise mipp.DecodeError("this is no 'MPEF (type=144)' file: '%s'" %
file_name)
def read_gts_message(file_name):
s = Segment(file_name)
if s.file_type == 1:
return s
else:
raise mipp.DecodeError("this is no 'GTS Message' file: '%s'" %
file_name)
def read_imagedata(file_name):
s = Segment(file_name)
if s.file_type == 0:
return ImageSegment(file_name)
else:
raise mipp.DecodeError("this is no 'image data' file: '%s'" %
file_name)
def readline(self, nlines=1):
if not self.fp:
self.fp = open(self.file_name)
read_headers(self.fp)
data = self.fp.read(self.bytes_per_line*nlines)
if not data:
raise mipp.DecodeError("could not read", self.bytes_per_line*nlines, "bytes")
return data
def decompress(infile, outdir='.'):
"""Will decompress an XRIT data file and return the path to the
decompressed file. It expect to find Eumetsat's xRITDecompress through the
environment variable XRIT_DECOMPRESS_PATH
"""
from subprocess import Popen, PIPE
cmd = os.environ.get('XRIT_DECOMPRESS_PATH', None)
if not cmd:
raise IOError("XRIT_DECOMPRESS_PATH is not defined" +
" (complete path to xRITDecompress)")
infile = os.path.abspath(infile)
cwd = os.getcwd()
os.chdir(outdir)
question = ("Did you set the environment variable " +
"XRIT_DECOMPRESS_PATH correctly?")
if not os.path.exists(cmd):
raise IOError(str(cmd) + " does not exist!\n" + question)
elif os.path.isdir(cmd):
raise IOError(str(cmd) + " is a directory!\n" + question)
p = Popen([cmd, infile], stdout=PIPE)
stdout = StringIO(p.communicate()[0])
status = p.returncode
os.chdir(cwd)
outfile = ''
for line in stdout:
try:
k, v = [x.strip() for x in line.split(':', 1)]
except ValueError:
break
if k == 'Decompressed file':
outfile = v
break
if status != 0:
raise mipp.DecodeError("xrit_decompress '%s', failed, status=%d" %
(infile, status))
if not outfile:
raise mipp.DecodeError(
"xrit_decompress '%s', failed, no output file is generated" %
infile)
return outdir + '/' + outfile
def _decode_data_definition(buf):
dd = dict()
lines = [x.strip() for x in buf.strip().split('\r')]
for a in lines:
k, v = [x.strip() for x in a.split(':=')]
if k[0] == '$':
dd[k] = int(v)
elif k[0] == '_':
dd[k] = v
elif k.isdigit():
dd[int(k)] = float(v)
else:
raise mipp.DecodeError("could not decode data definition: '%s'"%a)
return dd
def read_header(fp):
hdr_type = rbin.read_uint1(fp.read(1))
if hdr_type != 0:
raise mipp.DecodeError("first header has to be a Primary Header, this one is of type %d"%hdr_type)
phdr = PrimaryHeader(fp)
yield phdr
current_size = phdr.rec_len
while current_size < phdr.total_hdr_len:
hdr_type = rbin.read_uint1(fp.read(1))
cls = header_map.get(hdr_type, None)
if cls:
hdr = cls(fp)
else:
hdr = UnknownHeader(hdr_type, fp)
yield hdr
current_size += hdr.rec_len
def read_epilogue(file_name):
s = Segment(file_name)
if s.file_type == 129:
return s
else:
raise mipp.DecodeError("this is no 'epilogue' file: '%s'"%file_name)