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from __future__ import division, absolute_import, print_function
import sys
import copy
import binascii
LONG_DOUBLE_REPRESENTATION_SRC = r"""
/* "before" is 16 bytes to ensure there's no padding between it and "x".
* We're not expecting any "long double" bigger than 16 bytes or with
* alignment requirements stricter than 16 bytes. */
typedef %(type)s test_type;
struct {
char before[16];
test_type x;
char after[8];
} foo = {
{ '\0', '\0', '\0', '\0', '\0', '\0', '\0', '\0',
'\001', '\043', '\105', '\147', '\211', '\253', '\315', '\357' },
-123456789.0,
{ '\376', '\334', '\272', '\230', '\166', '\124', '\062', '\020' }
};
"""
def pyod(filename):
"""Python implementation of the od UNIX utility (od -b, more exactly).
Parameters
----------
filename : str
name of the file to get the dump from.
Returns
-------
out : seq
list of lines of od output
Note
----
We only implement enough to get the necessary information for long double
representation, this is not intended as a compatible replacement for od.
"""
def _pyod2():
out = []
fid = open(filename, 'r')
try:
yo = [int(oct(int(binascii.b2a_hex(o), 16))) for o in fid.read()]
for i in range(0, len(yo), 16):
line = ['%07d' % int(oct(i))]
line.extend(['%03d' % c for c in yo[i:i+16]])
out.append(" ".join(line))
return out
finally:
fid.close()
def _pyod3():
out = []
fid = open(filename, 'rb')
try:
yo2 = [oct(o)[2:] for o in fid.read()]
for i in range(0, len(yo2), 16):
line = ['%07d' % int(oct(i)[2:])]
line.extend(['%03d' % int(c) for c in yo2[i:i+16]])
out.append(" ".join(line))
return out
finally:
fid.close()
if sys.version_info[0] < 3:
return _pyod2()
else:
return _pyod3()
_BEFORE_SEQ = ['000', '000', '000', '000', '000', '000', '000', '000',
'001', '043', '105', '147', '211', '253', '315', '357']
_AFTER_SEQ = ['376', '334', '272', '230', '166', '124', '062', '020']
_IEEE_DOUBLE_BE = ['301', '235', '157', '064', '124', '000', '000', '000']
_IEEE_DOUBLE_LE = _IEEE_DOUBLE_BE[::-1]
_INTEL_EXTENDED_12B = ['000', '000', '000', '000', '240', '242', '171', '353',
'031', '300', '000', '000']
_INTEL_EXTENDED_16B = ['000', '000', '000', '000', '240', '242', '171', '353',
'031', '300', '000', '000', '000', '000', '000', '000']
_IEEE_QUAD_PREC_BE = ['300', '031', '326', '363', '105', '100', '000', '000',
'000', '000', '000', '000', '000', '000', '000', '000']
_IEEE_QUAD_PREC_LE = _IEEE_QUAD_PREC_BE[::-1]
_DOUBLE_DOUBLE_BE = ['301', '235', '157', '064', '124', '000', '000', '000'] + \
['000'] * 8
def long_double_representation(lines):
"""Given a binary dump as given by GNU od -b, look for long double
representation."""
# Read contains a list of 32 items, each item is a byte (in octal
# representation, as a string). We 'slide' over the output until read is of
# the form before_seq + content + after_sequence, where content is the long double
# representation:
# - content is 12 bytes: 80 bits Intel representation
# - content is 16 bytes: 80 bits Intel representation (64 bits) or quad precision
# - content is 8 bytes: same as double (not implemented yet)
read = [''] * 32
saw = None
for line in lines:
# we skip the first word, as od -b output an index at the beginning of
# each line
for w in line.split()[1:]:
read.pop(0)
read.append(w)
# If the end of read is equal to the after_sequence, read contains
# the long double
if read[-8:] == _AFTER_SEQ:
saw = copy.copy(read)
if read[:12] == _BEFORE_SEQ[4:]:
if read[12:-8] == _INTEL_EXTENDED_12B:
return 'INTEL_EXTENDED_12_BYTES_LE'
elif read[:8] == _BEFORE_SEQ[8:]:
if read[8:-8] == _INTEL_EXTENDED_16B:
return 'INTEL_EXTENDED_16_BYTES_LE'
elif read[8:-8] == _IEEE_QUAD_PREC_BE:
return 'IEEE_QUAD_BE'
elif read[8:-8] == _IEEE_QUAD_PREC_LE:
return 'IEEE_QUAD_LE'
elif read[8:-8] == _DOUBLE_DOUBLE_BE:
return 'DOUBLE_DOUBLE_BE'
elif read[:16] == _BEFORE_SEQ:
if read[16:-8] == _IEEE_DOUBLE_LE:
return 'IEEE_DOUBLE_LE'
elif read[16:-8] == _IEEE_DOUBLE_BE:
return 'IEEE_DOUBLE_BE'
if saw is not None:
raise ValueError("Unrecognized format (%s)" % saw)
else:
# We never detected the after_sequence
raise ValueError("Could not lock sequences (%s)" % saw)
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