def _write_sac(stream, filename, byteorder="<", **kwargs): # @UnusedVariable
"""
Writes a SAC file.
.. warning::
This function should NOT be called directly, it registers via the
the :meth:`~obspy.core.stream.Stream.write` method of an
ObsPy :class:`~obspy.core.stream.Stream` object, call this instead.
:param stream: The ObsPy Stream object to write.
:type stream: :class:`~obspy.core.stream.Stream`
:param filename: Name of file to write. In case an open file or
file-like object is passed, this function only supports writing
Stream objects containing a single Trace. This is a limitation of
the SAC file format. An exception will be raised in case it's
necessary.
:type filename: str, open file, or file-like object
:param byteorder: Must be either ``0`` or ``'<'`` for LSBF or
little-endian, ``1`` or ``'>'`` for MSBF or big-endian.
Defaults to little endian.
:type byteorder: int or str
.. rubric:: Example
>>> from obspy import read
>>> st = read()
>>> st.write("test.sac", format="SAC") #doctest: +SKIP
"""
# Bytes buffer are ok, but only if the Stream object contains only one
# Trace. SAC can only store one Trace per file.
if is_bytes_buffer(filename):
if len(stream) > 1:
raise ValueError("If writing to a file-like object in the SAC "
"format, the Stream object can only contain "
"one Trace.")
__write_sac(stream[0], filename, byteorder=byteorder, **kwargs)
return
elif isinstance(filename, (str, bytes)):
# Otherwise treat it as a filename
# Translate the common (renamed) entries
base, ext = os.path.splitext(filename)
for i, trace in enumerate(stream):
if len(stream) != 1:
filename = "%s%02d%s" % (base, i + 1, ext)
with open(filename, "wb") as fh:
__write_sac(trace, fh, byteorder=byteorder, **kwargs)
else:
raise ValueError("Cannot open '%s'." % filename)
def _read_sac(filename, headonly=False, debug_headers=False, fsize=True,
**kwargs): # @UnusedVariable
"""
Reads an SAC file and returns an ObsPy Stream object.
.. warning::
This function should NOT be called directly, it registers via the
ObsPy :func:`~obspy.core.stream.read` function, call this instead.
:param filename: SAC file to be read.
:type filename: str, open file, or file-like object
:param headonly: If set to True, read only the head. This is most useful
for scanning available data in huge (temporary) data sets.
:type headonly: bool
:param debug_headers: Extracts also the SAC headers ``'nzyear', 'nzjday',
'nzhour', 'nzmin', 'nzsec', 'nzmsec', 'delta', 'scale', 'npts',
'knetwk', 'kstnm', 'kcmpnm'`` which are usually directly mapped to the
:class:`~obspy.core.stream.Stream` object if set to ``True``. Those
values are not synchronized with the Stream object itself and won't
be used during writing of a SAC file! Defaults to ``False``.
:type debug_headers: bool
:param fsize: Check if file size is consistent with theoretical size
from header. Defaults to ``True``.
:type fsize: bool
:rtype: :class:`~obspy.core.stream.Stream`
:return: A ObsPy Stream object.
.. rubric:: Example
>>> from obspy import read # doctest: +SKIP
>>> st = read("/path/to/test.sac") # doctest: +SKIP
"""
# Only byte buffers for binary SAC.
if is_bytes_buffer(filename):
return _internal_read_sac(buf=filename, headonly=headonly,
debug_headers=debug_headers, fsize=fsize,
**kwargs)
elif isinstance(filename, (str, bytes)):
with open(filename, "rb") as fh:
return _internal_read_sac(buf=fh, headonly=headonly,
debug_headers=debug_headers, fsize=fsize,
**kwargs)
else:
raise ValueError("Cannot open '%s'." % filename)
def _is_sac(filename):
"""
Checks whether a file is a SAC file or not.
:param filename: SAC file to be checked.
:type filename: str, open file, or file-like object
:rtype: bool
:return: ``True`` if a SAC file.
.. rubric:: Example
>>> _is_sac('/path/to/test.sac') #doctest: +SKIP
"""
if is_bytes_buffer(filename):
return __is_sac(filename)
elif isinstance(filename, (str, bytes)):
with open(filename, "rb") as fh:
return __is_sac(fh)
else:
raise ValueError("Cannot open '%s'." % filename)
def _is_sac(filename):
"""
Checks whether a file is a SAC file or not.
:param filename: SAC file to be checked.
:type filename: str, open file, or file-like object
:rtype: bool
:return: ``True`` if a SAC file.
.. rubric:: Example
>>> from obspy.core.util import get_example_file
>>> _is_sac(get_example_file('test.sac'))
True
>>> _is_sac(get_example_file('test.mseed'))
False
"""
if is_bytes_buffer(filename):
return _internal_is_sac(filename)
elif isinstance(filename, (str, bytes)):
with open(filename, "rb") as fh:
return _internal_is_sac(fh)
else:
raise ValueError("Cannot open '%s'." % filename)
def _is_sac(filename):
"""
Checks whether a file is a SAC file or not.
:param filename: SAC file to be checked.
:type filename: str, open file, or file-like object
:rtype: bool
:return: ``True`` if a SAC file.
.. rubric:: Example
>>> from obspy.core.util import get_example_file
>>> _is_sac(get_example_file('test.sac'))
True
>>> _is_sac(get_example_file('test.mseed'))
False
"""
if is_bytes_buffer(filename):
return _internal_is_sac(filename)
elif isinstance(filename, (str, bytes)):
with open(filename, "rb") as fh:
return _internal_is_sac(fh)
else:
raise ValueError("Cannot open '%s'." % filename)
def _read_sac_xy(filename, headonly=False, debug_headers=False,
**kwargs): # @UnusedVariable
"""
Reads an alphanumeric SAC file and returns an ObsPy Stream object.
.. warning::
This function should NOT be called directly, it registers via the
ObsPy :func:`~obspy.core.stream.read` function, call this instead.
:param filename: Alphanumeric SAC file to be read.
:type filename: str, open file, or file-like object
:param headonly: If set to True, read only the head. This is most useful
for scanning available data in huge (temporary) data sets.
:type headonly: bool
:param debug_headers: Extracts also the SAC headers ``'nzyear', 'nzjday',
'nzhour', 'nzmin', 'nzsec', 'nzmsec', 'delta', 'scale', 'npts',
'knetwk', 'kstnm', 'kcmpnm'`` which are usually directly mapped to the
:class:`~obspy.core.stream.Stream` object if set to ``True``. Those
values are not synchronized with the Stream object itself and won't
be used during writing of a SAC file! Defaults to ``False``.
:type debug_headers: bool
:rtype: :class:`~obspy.core.stream.Stream`
:return: A ObsPy Stream object.
.. rubric:: Example
>>> from obspy import read
>>> st = read("/path/to/testxy.sac")
"""
if is_bytes_buffer(filename):
return _internal_read_sac_xy(buf=filename, headonly=headonly,
debug_headers=debug_headers, **kwargs)
else:
with open(filename, "rb") as fh:
return _internal_read_sac_xy(buf=fh, headonly=headonly,
debug_headers=debug_headers, **kwargs)
def _read_sac_xy(filename, headonly=False, debug_headers=False,
**kwargs): # @UnusedVariable
"""
Reads an alphanumeric SAC file and returns an ObsPy Stream object.
.. warning::
This function should NOT be called directly, it registers via the
ObsPy :func:`~obspy.core.stream.read` function, call this instead.
:param filename: Alphanumeric SAC file to be read.
:type filename: str, open file, or file-like object
:param headonly: If set to True, read only the head. This is most useful
for scanning available data in huge (temporary) data sets.
:type headonly: bool
:param debug_headers: Extracts also the SAC headers ``'nzyear', 'nzjday',
'nzhour', 'nzmin', 'nzsec', 'nzmsec', 'delta', 'scale', 'npts',
'knetwk', 'kstnm', 'kcmpnm'`` which are usually directly mapped to the
:class:`~obspy.core.stream.Stream` object if set to ``True``. Those
values are not synchronized with the Stream object itself and won't
be used during writing of a SAC file! Defaults to ``False``.
:type debug_headers: bool
:rtype: :class:`~obspy.core.stream.Stream`
:return: A ObsPy Stream object.
.. rubric:: Example
>>> from obspy import read # doctest: +SKIP
>>> st = read("/path/to/testxy.sac") # doctest: +SKIP
"""
if is_bytes_buffer(filename):
return _internal_read_sac_xy(buf=filename, headonly=headonly,
debug_headers=debug_headers, **kwargs)
else:
with open(filename, "rb") as fh:
return _internal_read_sac_xy(buf=fh, headonly=headonly,
debug_headers=debug_headers, **kwargs)
