def read_header(filename, verbose=False):
"""Read the header of a filterbank file, and return
a dictionary of header paramters and the header's
size in bytes.
Inputs:
filename: Name of the filterbank file.
verbose: If True, be verbose. (Default: be quiet)
Outputs:
header: A dictionary of header paramters.
header_size: The size of the header in bytes.
"""
header = {}
filfile = open(filename, 'rb')
filfile.seek(0)
paramname = ""
while (paramname != 'HEADER_END'):
if verbose:
print "File location: %d" % filfile.tell()
paramname, val = sigproc.read_hdr_val(filfile, stdout=verbose)
if verbose:
print "Read param %s (value: %s)" % (paramname, val)
if paramname not in ["HEADER_START", "HEADER_END"]:
header[paramname] = val
header_size = filfile.tell()
filfile.close()
return header, header_size
def read_header(filename, verbose=False):
"""Read the header of a filterbank file, and return
a dictionary of header paramters and the header's
size in bytes.
Inputs:
filename: Name of the filterbank file.
verbose: If True, be verbose. (Default: be quiet)
Outputs:
header: A dictionary of header paramters.
header_size: The size of the header in bytes.
"""
header = {}
filfile = open(filename, 'rb')
filfile.seek(0)
paramname = ""
while (paramname != 'HEADER_END'):
if verbose:
print "File location: %d" % filfile.tell()
paramname, val = sigproc.read_hdr_val(filfile, stdout=verbose)
if verbose:
print "Read param %s (value: %s)" % (paramname, val)
if paramname not in ["HEADER_START", "HEADER_END"]:
header[paramname] = val
header_size = filfile.tell()
filfile.close()
return header, header_size
def read_filterbank(filename,DM,bin_start,duration,offset,RFI_reduct=False,mask=False):
if (not 'filterbank' in sys.modules) or (not 'sigproc' in sys.modules):
logging.warning("Utilities - Additional modules missing")
return
bin_start = np.int(bin_start)
#Read data from filterbank file
head = filterbank.read_header(filename)[0]
nbits = head['nbits']
nchans = head['nchans']
dtype = filterbank.get_dtype(nbits)
filfile = open(filename, 'rb')
filfile.seek(0)
paramname = ""
while (paramname != 'HEADER_END'): paramname, val = sigproc.read_hdr_val(filfile)
header_size = filfile.tell()
filfile.close()
file_size = os.stat(filename)[6]
data_size = file_size - header_size
bytes_per_spectrum= nchans * nbits / 8
nspec = data_size / bytes_per_spectrum
bin_start -= offset
if bin_start<0: bin_start = 0
bin_end = bin_start + DM2delay(DM) + duration + 2*offset
if bin_end >= nspec: bin_end = nspec
spectrum = np.memmap(filename, dtype=dtype, mode='r', offset=header_size, shape=(nspec, nchans))
spectrum = spectrum[bin_start:bin_end].copy()
spectrum = np.fliplr(spectrum)
if mask:
#Zap the channels from the mask file
zap_chans, zap_ints, chans_per_int, ptsperint = read_mask(mask,bin_start,bin_end)
med_value = np.median(spectrum)
spectrum[:,zap_chans] = med_value
zap_ints = zap_ints[(zap_ints>=bin_start)&(zap_ints<=bin_end)]
zap_ints -= bin_start
spectrum[zap_ints,:] = med_value
mask_start = int(np.floor(float(bin_start)/ptsperint)) * ptsperint - bin_start
for i,chans in enumerate(chans_per_int):
idx_start = mask_start + i * ptsperint
idx_end = mask_start + (i + 1) * ptsperint
spectrum[idx_start:idx_end,chans] = med_value
if RFI_reduct:
np.clip(spectrum - np.median(spectrum,axis=0) + 128, 0, 255, out=spectrum)
return spectrum
def read_header(self):
if not self.already_read_header:
self.header_params = []
self.header = {}
self.already_read_header = True
self.seek_to_header_start()
param = ""
while (param != 'HEADER_END'):
param, val = sigproc.read_hdr_val(self.filfile)
self.header[param] = val
self.header_params.append(param)
# Calculate additional information
# Such as: datatype, numsamps, datasize, hdrsize
if self.nbits == 32:
self.dtype = 'float32'
else:
self.dtype = 'uint%d' % self.nbits
self.header_size = self.filfile.tell()
self.data_size = os.stat(self.filename)[6] - self.header_size
bytes_per_sample = self.nchans * (self.nbits / 8)
if self.data_size % bytes_per_sample:
warnings.warn("Not an integer number of samples in file.")
self.number_of_samples = self.data_size / bytes_per_sample
def read_header(self):
if not self.already_read_header:
self.header_params = []
self.header = {}
self.already_read_header = True
self.seek_to_header_start()
param = ""
while (param != 'HEADER_END'):
param, val = sigproc.read_hdr_val(self.filfile)
self.header[param] = val
self.header_params.append(param)
# Calculate additional information
# Such as: datatype, numsamps, datasize, hdrsize
if self.nbits == 32:
self.dtype = 'float32'
else:
self.dtype = 'uint%d' % self.nbits
self.header_size = self.filfile.tell()
self.data_size = os.stat(self.filename)[6] - self.header_size
bytes_per_sample = self.nchans * (self.nbits/8)
if self.data_size % bytes_per_sample:
warnings.warn("Not an integer number of samples in file.")
self.number_of_samples = self.data_size / bytes_per_sample
basefilenm = sys.argv[2][:sys.argv[2].find(".fil")]
filhdr = {}
newhdr = ""
infile = open(sys.argv[2], 'rb')
# Determine the full size of the file
infile.seek(0, 2)
infilelen = infile.tell()
infile.seek(0, 0)
outfile = open(basefilenm+"_DS%d.fil"%DS_fact, 'wb')
# Loop over the values in the .fil file
while 1:
param, val = sigproc.read_hdr_val(infile, stdout=False)
filhdr[param] = val
if param=="tsamp":
val *= DS_fact
# Append to the new hdr string
newhdr += sigproc.addto_hdr(param, val)
# Break out of the loop if the header is over
if param=="HEADER_END":
break
# Write the new header to the output file
outfile.write(newhdr)
