/usr/share/pyshared/fabio/readbytestream.py is in python-fabio 0.1.4-1.
This file is owned by root:root, with mode 0o644.
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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 | #!/usr/bin/env python
#coding: utf8
"""
Reads a bytestream
Authors: Jon Wright Henning O. Sorensen & Erik Knudsen
ESRF Risoe National Laboratory
"""
# Get ready for python3:
from __future__ import with_statement, print_function, division
import numpy, logging
logger = logging.getLogger("readbytestream")
DATATYPES = {
# type sign bytes
("int", 'n', 1) : numpy.uint8,
("int", 'n', 2) : numpy.uint16,
("int", 'n', 4) : numpy.uint32,
("int", 'y', 1) : numpy.int8,
("int", 'y', 2) : numpy.int16,
("int", 'y', 4) : numpy.int32,
('float', 'y', 4) : numpy.float32, # does this occur in bruker?
('double', 'y', 4): numpy.float64
}
def readbytestream(fil,
offset,
x,
y,
nbytespp,
datatype='int',
signed='n',
swap='n',
typeout=numpy.uint16):
"""
Reads in a bytestream from a file (which may be a string indicating
a filename, or an already opened file (should be "rb"))
offset is the position (in bytes) where the pixel data start
nbytespp = number of bytes per pixel
type can be int or float (4 bytes pp) or double (8 bytes pp)
signed: normally signed data 'y', but 'n' to try to get back the
right numbers when unsigned data are converted to signed
(python once had no unsigned numeric types.)
swap, normally do not bother, but 'y' to swap bytes
typeout is the numpy type to output, normally uint16,
but more if overflows occurred
x and y are the pixel dimensions
TODO : Read in regions of interest
PLEASE LEAVE THE STRANGE INTERFACE ALONE -
IT IS USEFUL FOR THE BRUKER FORMAT
"""
tin = "dunno"
length = nbytespp * x * y # bytes per pixel times number of pixels
if datatype in ['float', 'double']:
signed = 'y'
key = (datatype, signed, nbytespp)
try:
tin = DATATYPES[key]
except:
logging.warning("datatype,signed,nbytespp " + str(key))
raise Exception("Unknown combination of types to readbytestream")
# Did we get a string (filename) or a readable stream object?
if hasattr(fil, "read") and hasattr(fil, "seek"):
infile = fil
opened = False
else:
infile = open(fil, 'rb')
opened = True
infile.seek(offset)
arr = numpy.array(numpy.reshape(
numpy.fromstring(
infile.read(length), tin) , (x, y)), typeout)
if swap == 'y':
arr = arr.byteswap()
if opened:
infile.close()
return arr
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