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# http://pyrocko.org - GPLv3
#
# The Pyrocko Developers, 21st Century
# ---|P------/S----------~Lg----------
from __future__ import division, absolute_import
import os
import numpy as num
from pyrocko import util, trace
from .io_common import FileLoadError
class KanError(Exception):
pass
class KanFile:
nbytes_header = 512
def __init__(self, *args, **kwargs):
if args:
self.read(*args, **kwargs)
else:
self.clear()
def clear(self):
'''Empty file record.'''
# set the required attributes
self.delta = 1.0
self.npts = 0
self.b = 0.0
self.data = [num.arange(0, dtype=num.int32)]
def read(self, filename, load_data=True):
'''Read SAC file.
filename -- Name of KAN file.
load_data -- If True, the data is read, otherwise only read headers.
'''
nbh = KanFile.nbytes_header
# read in all data
with open(filename, 'rb') as f:
if load_data:
filedata = f.read()
else:
filedata = f.read(nbh)
if len(filedata) < nbh:
raise KanError('File too short to be a KAN file.')
header_records = int(filedata[0:8])
npts = int(filedata[8:20])
leven = int(filedata[20:28])
datatype = int(filedata[28:36])
rate = float(filedata[36:50])
offset = float(filedata[50:64])
byte_sex = ('little', 'big')[int(filedata[382:390])]
assert header_records == 1
assert leven == 1
assert datatype == 2
assert offset == 0.0
date = str(filedata[393:405].decode('ascii')).strip()
tim = str(filedata[405:415].decode('ascii')).strip()
microseconds = int(filedata[415:423])
ref_time = util.ctimegm('%s %s' % (date, tim)) + microseconds/1.0e6
stationname = os.path.basename(filename)
stationname = stationname.replace('.kan', '')
stationname = stationname.replace('.KAN', '')
self.npts = npts
self.delta = 1.0/rate
self.kstnm = stationname
self.ref_time = ref_time
if load_data:
if byte_sex == 'little':
dtype = '<i4'
else:
dtype = '>i4'
self.data = num.fromstring(filedata[nbh:], dtype=dtype)
assert self.data.size == self.npts
else:
self.data = None
def to_trace(self):
return trace.Trace(
'', self.kstnm, '', '',
self.ref_time,
self.ref_time+self.delta*(self.npts-1),
self.delta,
self.data)
def iload(filename, load_data):
try:
kanf = KanFile(filename, load_data=load_data)
tr = kanf.to_trace()
yield tr
except (OSError, KanError) as e:
raise FileLoadError(e)
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