def test_values_text_header_creation():
lines = {i + 1: chr(64 + i) * 76 for i in range(40)}
text_header = segyio.create_text_header(lines)
for line_no in range(0, 40):
line = text_header[line_no * 80: (line_no + 1) * 80]
assert line == "C{0:>2} {1:76}".format(line_no + 1, chr(64 + line_no) * 76)
def test_read_text_header(mmap=False):
f = _segyio.segyiofd("test-data/small.sgy", "r")
if mmap:
f.mmap()
lines = {
1: "DATE: 2016-09-19",
2: "AN INCREASE IN AMPLITUDE EQUALS AN INCREASE IN ACOUSTIC IMPEDANCE",
3: "Written by libsegyio (python)",
11: "TRACE HEADER POSITION:",
12: " INLINE BYTES 189-193 | OFFSET BYTES 037-041",
13: " CROSSLINE BYTES 193-197 |",
15: "END EBCDIC HEADER"
}
rows = segyio.create_text_header(lines)
rows = bytearray(rows, 'ascii') # mutable array of bytes
rows[-1] = 128 # \x80
actual_text_header = bytes(rows)
assert f.gettext(0) == actual_text_header
with pytest.raises(Exception):
_segyio.read_texthdr(None, 0)
f.close()
def default_text_header(iline, xline, offset):
lines = {
1: "DATE %s" % datetime.date.today().isoformat(),
2: "AN INCREASE IN AMPLITUDE EQUALS AN INCREASE IN ACOUSTIC IMPEDANCE",
3: "Written by libsegyio (python)",
11: "TRACE HEADER POSITION:",
12: " INLINE BYTES %03d-%03d | OFFSET BYTES %03d-%03d" % (iline, iline + 4, int(offset), int(offset) + 4),
13: " CROSSLINE BYTES %03d-%03d |" % (xline, xline + 4),
15: "END EBCDIC HEADER",
}
rows = segyio.create_text_header(lines)
rows = bytearray(rows, 'ascii') # mutable array of bytes
rows[-1] = 128 # \x80 -- Unsure if this is really required...
return bytes(rows) # immutable array of bytes that is compatible with strings
def setUp(self):
self.filename = "test-data/small.sgy"
lines = {
1: "DATE: 2016-09-19",
2: "AN INCREASE IN AMPLITUDE EQUALS AN INCREASE IN ACOUSTIC IMPEDANCE",
3: "Written by libsegyio (python)",
11: "TRACE HEADER POSITION:",
12: " INLINE BYTES 189-193 | OFFSET BYTES 037-041",
13: " CROSSLINE BYTES 193-197 |",
15: "END EBCDIC HEADER"
}
rows = segyio.create_text_header(lines)
rows = bytearray(rows, 'ascii') # mutable array of bytes
rows[-1] = 128 # \x80
self.ACTUAL_TEXT_HEADER = bytes(rows)
def test_empty_text_header_creation():
text_header = segyio.create_text_header({})
for line_no in range(0, 40):
line = text_header[line_no * 80: (line_no + 1) * 80]
assert line == "C{0:>2} {1:76}".format(line_no + 1, "")
