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#A place for code to be called from C-code
# that implements more complicated stuff.
import re
from multiarray import dtype, ndarray
# make sure the tuple entries are PyArray_Descr
# or convert them
#
# make sure offsets are all interpretable
# as positive integers and
# convert them to positive integers if so
#
#
# return totalsize from last offset and size
# Called in PyArray_DescrConverter function when
# a dictionary without "names" and "formats"
# fields is used as a data-type descriptor.
def _usefields(adict, align):
try:
names = adict[-1]
except KeyError:
names = None
if names is None:
allfields = []
fnames = adict.keys()
for fname in fnames:
obj = adict[fname]
n = len(obj)
if not isinstance(obj, tuple) or n not in [2,3]:
raise ValueError, "entry not a 2- or 3- tuple"
if (n > 2) and (obj[2] == fname):
continue
num = int(obj[1])
if (num < 0):
raise ValueError, "invalid offset."
format = dtype(obj[0])
if (format.itemsize == 0):
raise ValueError, "all itemsizes must be fixed."
if (n > 2):
title = obj[2]
else:
title = None
allfields.append((fname, format, num, title))
# sort by offsets
allfields.sort(lambda x,y: cmp(x[2],y[2]))
names = [x[0] for x in allfields]
formats = [x[1] for x in allfields]
offsets = [x[2] for x in allfields]
titles = [x[3] for x in allfields]
else:
formats = []
offsets = []
titles = []
for name in names:
res = adict[name]
formats.append(res[0])
offsets.append(res[1])
if (len(res) > 2):
titles.append(res[2])
else:
titles.append(None)
return dtype({"names" : names,
"formats" : formats,
"offsets" : offsets,
"titles" : titles}, align)
# construct an array_protocol descriptor list
# from the fields attribute of a descriptor
# This calls itself recursively but should eventually hit
# a descriptor that has no fields and then return
# a simple typestring
def _array_descr(descriptor):
fields = descriptor.fields
if fields is None:
return descriptor.str
ordered_fields = [fields[x] + (x,) for x in fields[-1]]
result = []
offset = 0
for field in ordered_fields:
if field[1] > offset:
result.append(('','|V%d' % (field[1]-offset)))
if len(field) > 3:
name = (field[2],field[3])
else:
name = field[2]
if field[0].subdtype:
tup = (name, _array_descr(field[0].subdtype[0]),
field[0].subdtype[1])
else:
tup = (name, _array_descr(field[0]))
offset += field[0].itemsize
result.append(tup)
return result
def _reconstruct(subtype, shape, dtype):
return ndarray.__new__(subtype, shape, dtype)
# format_re and _split were taken from numarray by J. Todd Miller
def _split(input):
"""Split the input formats string into field formats without splitting
the tuple used to specify multi-dimensional arrays."""
newlist = []
hold = ''
for element in input.split(','):
if hold != '':
item = hold + ',' + element
else:
item = element
left = item.count('(')
right = item.count(')')
# if the parenthesis is not balanced, hold the string
if left > right :
hold = item
# when balanced, append to the output list and reset the hold
elif left == right:
newlist.append(item.strip())
hold = ''
# too many close parenthesis is unacceptable
else:
raise SyntaxError, item
# if there is string left over in hold
if hold != '':
raise SyntaxError, hold
return newlist
format_re = re.compile(r'(?P<repeat> *[(]?[ ,0-9]*[)]? *)(?P<dtype>[><|A-Za-z0-9.]*)')
# astr is a string (perhaps comma separated)
def _commastring(astr):
res = _split(astr)
if (len(res)) < 1:
raise ValueError, "unrecognized formant"
result = []
for k,item in enumerate(res):
# convert item
try:
(repeats, dtype) = format_re.match(item).groups()
except (TypeError, AttributeError):
raise ValueError('format %s is not recognized' % item)
if (repeats == ''):
newitem = dtype
else:
newitem = (dtype, eval(repeats))
result.append(newitem)
return result
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