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# -*- coding: utf-8 -*-
# Copyright 2010 Stefano Mazzucco
#
# This file is part of dm3_data_plugin.
#
# dm3_data_plugin is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 2 of the License, or
# (at your option) any later version.
#
# dm3_data_plugin is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with RosettaSciIO; if not, write to the Free Software
# Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301
# USA
# general functions for reading data from files
import logging
import struct
from rsciio.utils.exceptions import ByteOrderError
_logger = logging.getLogger(__name__)
# Declare simple TagDataType structures for faster execution.
# The variables are named as following:
# Endianness_type
# Endianness = B (big) or L (little)
# type = (u)short, (u)long, float, double, bool (unsigned char),
# byte (signed char), char
B_short = struct.Struct(">h")
L_short = struct.Struct("<h")
B_ushort = struct.Struct(">H")
L_ushort = struct.Struct("<H")
B_long = struct.Struct(">l")
L_long = struct.Struct("<l")
B_long_long = struct.Struct(">q")
L_long_long = struct.Struct("<q")
B_ulong = struct.Struct(">L")
L_ulong = struct.Struct("<L")
B_ulong_long = struct.Struct(">Q")
L_ulong_long = struct.Struct("<Q")
B_float = struct.Struct(">f")
L_float = struct.Struct("<f")
B_double = struct.Struct(">d")
L_double = struct.Struct("<d")
B_bool = struct.Struct(">B") # use unsigned char
L_bool = struct.Struct("<B")
B_byte = struct.Struct(">b") # use signed char
L_byte = struct.Struct("<b")
B_char = struct.Struct(">c")
L_char = struct.Struct("<c")
def read_short(f, endian):
"""Read a 2-Byte integer from file f
with a given endianness (byte order).
endian can be either 'big' or 'little'.
"""
if (endian != "little") and (endian != "big"):
_logger.debug("File address:", f.tell())
raise ByteOrderError(endian)
else:
data = f.read(2) # hexadecimal representation
if endian == "big":
s = B_short
elif endian == "little":
s = L_short
return s.unpack(data)[0] # struct.unpack returns a tuple
def read_ushort(f, endian):
"""Read a 2-Byte integer from file f
with a given endianness (byte order).
endian can be either 'big' or 'little'.
"""
if (endian != "little") and (endian != "big"):
_logger.debug("File address:", f.tell())
raise ByteOrderError(endian)
else:
data = f.read(2)
if endian == "big":
s = B_ushort
elif endian == "little":
s = L_ushort
return s.unpack(data)[0]
def read_long(f, endian):
"""Read a 4-Byte integer from file f
with a given endianness (byte order).
endian can be either 'big' or 'little'.
"""
if (endian != "little") and (endian != "big"):
_logger.debug("File address:", f.tell())
raise ByteOrderError(endian)
else:
data = f.read(4)
if endian == "big":
s = B_long
elif endian == "little":
s = L_long
return s.unpack(data)[0]
def read_long_long(f, endian):
"""Read a 8-Byte integer from file f
with a given endianness (byte order).
endian can be either 'big' or 'little'.
"""
if (endian != "little") and (endian != "big"):
_logger.debug("File address:", f.tell())
raise ByteOrderError(endian)
else:
data = f.read(8)
if endian == "big":
s = B_long_long
elif endian == "little":
s = L_long_long
return s.unpack(data)[0]
def read_ulong(f, endian):
"""Read a 4-Byte integer from file f
with a given endianness (byte order).
endian can be either 'big' or 'little'.
"""
if (endian != "little") and (endian != "big"):
_logger.debug("File address:", f.tell())
raise ByteOrderError(endian)
else:
data = f.read(4)
if endian == "big":
s = B_ulong
elif endian == "little":
s = L_ulong
return s.unpack(data)[0]
def read_ulong_long(f, endian):
"""Read a 8-Byte integer from file f
with a given endianness (byte order).
endian can be either 'big' or 'little'.
"""
if (endian != "little") and (endian != "big"):
_logger.debug("File address:", f.tell())
raise ByteOrderError(endian)
else:
data = f.read(8)
if endian == "big":
s = B_ulong_long
elif endian == "little":
s = L_ulong_long
return s.unpack(data)[0]
def read_float(f, endian):
"""Read a 4-Byte floating point from file f
with a given endianness (byte order).
endian can be either 'big' or 'little'.
"""
if (endian != "little") and (endian != "big"):
_logger.debug("File address:", f.tell())
raise ByteOrderError(endian)
else:
data = f.read(4)
if endian == "big":
s = B_float
elif endian == "little":
s = L_float
return s.unpack(data)[0]
def read_double(f, endian):
"""Read a 8-Byte floating point from file f
with a given endianness (byte order).
endian can be either 'big' or 'little'.
"""
if (endian != "little") and (endian != "big"):
_logger.debug("File address:", f.tell())
raise ByteOrderError(endian)
else:
data = f.read(8)
if endian == "big":
s = B_double
elif endian == "little":
s = L_double
return s.unpack(data)[0]
def read_boolean(f, endian):
"""Read a 1-Byte charater from file f
with a given endianness (byte order).
endian can be either 'big' or 'little'.
"""
if (endian != "little") and (endian != "big"):
_logger.debug("File address:", f.tell())
raise ByteOrderError(endian)
else:
data = f.read(1)
if endian == "big":
s = B_bool
elif endian == "little":
s = L_bool
return s.unpack(data)[0]
def read_byte(f, endian):
"""Read a 1-Byte charater from file f
with a given endianness (byte order).
endian can be either 'big' or 'little'.
"""
if (endian != "little") and (endian != "big"):
_logger.debug("File address:", f.tell())
raise ByteOrderError(endian)
else:
data = f.read(1)
if endian == "big":
s = B_byte
elif endian == "little":
s = L_byte
return s.unpack(data)[0]
def read_char(f, endian):
"""Read a 1-Byte charater from file f
with a given endianness (byte order).
endian can be either 'big' or 'little'.
"""
if (endian != "little") and (endian != "big"):
_logger.debug("File address:", f.tell())
raise ByteOrderError(endian)
else:
data = f.read(1)
if endian == "big":
s = B_char
elif endian == "little":
s = L_char
return s.unpack(data)[0]
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