diff options
Diffstat (limited to 'scipy/base/records.py')
| -rw-r--r-- | scipy/base/records.py | 150 |
1 files changed, 139 insertions, 11 deletions
diff --git a/scipy/base/records.py b/scipy/base/records.py index 0b2a6be6a..ec259aad4 100644 --- a/scipy/base/records.py +++ b/scipy/base/records.py @@ -4,7 +4,10 @@ import numeric as sb import numerictypes as nt import sys import types -import re +import re, stat, os + +_sysbyte = sys.byteorder +_byteorders = ['big','little'] # formats regular expression # allows multidimension spec with a tuple syntax in front @@ -253,7 +256,8 @@ class record(nt.void): class recarray(sb.ndarray): def __new__(subtype, shape, formats, names=None, titles=None, - buf=None, offset=0, strides=None, swap=0, aligned=0): + buf=None, offset=0, strides=None, byteorder=_sysbyte, + aligned=0): if isinstance(formats, sb.dtypedescr): descr = formats @@ -267,10 +271,11 @@ class recarray(sb.ndarray): raise ValueError, "Can only deal with alignment"\ "for list and dictionary type-descriptors." descr = sb.dtypedescr(formats, aligned) - + if buf is None: self = sb.ndarray.__new__(subtype, shape, (record, descr)) else: + swap = ((byteorder != _sysbyte) and (byteorder in _byteorders)) self = sb.ndarray.__new__(subtype, shape, (record, descr), buffer=buf, swap=swap) return self @@ -295,7 +300,7 @@ class recarray(sb.ndarray): def fromarrays(arrayList, formats=None, names=None, titles=None, shape=None, - swap=0, aligned=0): + aligned=0): """ create a record array from a (flat) list of arrays >>> x1=array([1,2,3,4]) @@ -338,7 +343,7 @@ def fromarrays(arrayList, formats=None, names=None, titles=None, shape=None, parsed = format_parser(formats, names, titles, aligned) _names = parsed._names - _array = recarray(shape, parsed._descr, swap=swap) + _array = recarray(shape, parsed._descr) # populate the record array (makes a copy) for i in range(len(arrayList)): @@ -346,8 +351,9 @@ def fromarrays(arrayList, formats=None, names=None, titles=None, shape=None, return _array +# shape must be 1-d def fromrecords(recList, formats=None, names=None, titles=None, shape=None, - swap=0, aligned=0): + aligned=0): """ create a Record Array from a list of records in text form The data in the same field can be heterogeneous, they will be promoted @@ -376,25 +382,147 @@ def fromrecords(recList, formats=None, names=None, titles=None, shape=None, if (shape is None or shape == 0): shape = len(recList) - if isinstance(shape, int): + if isinstance(shape, (int, long)): shape = (shape,) + if len(shape > 1): + raise ValueError, "Can only deal with 1-d list of records" + nfields = len(recList[0]) if formats is None: # slower obj = sb.array(recList,dtype=object) arrlist = [sb.array(obj[:,i].tolist()) for i in xrange(nfields)] return fromarrays(arrlist, formats=formats, shape=shape, names=names, - titles=titles, swap=swap, aligned=aligned) + titles=titles, aligned=aligned) parsed = format_parser(formats, names, titles, aligned) _names = parsed._names - _array = recarray(shape, parsed._descr, swap=swap) - + _array = recarray(shape, parsed._descr) farr = _array.flat - + for k in xrange(_array.size): for j in xrange(nfields): farr[k][_names[j]] = recList[k][j] return _array +def fromstring(datastring, formats, shape=None, names=None, titles=None, + byteorder=_sysbyte, aligned=0, offset=0): + """ create a (read-only) record array from binary data contained in + a string""" + + formats = format_parser(formats, names, titles, aligned) + itemsize = parsed._descr.itemsize + if (shape is None or shape == 0 or shape == -1): + shape = (len(datastring)-offset) / itemsize + + _array = recarray(shape, parsed._descr, shape=shape, names=names, + titles=titles, buf=datastring, offset=offset, + byteorder=byteorder) + return _array + +def fromfile(fd, formats, shape=None, names=None, titles=None, + byteorder=_sysbyte, aligned=0, offset=0): + """Create an array from binary file data + + If file is a string then that file is opened, else it is assumed + to be a file object. No options at the moment, all file positioning + must be done prior to this function call with a file object + + >>> import testdata, sys + >>> fd=open(testdata.filename) + >>> fd.seek(2880*2) + >>> r=fromfile(fd, formats='f8,i4,a5', shape=3, byteorder='big') + >>> print r[0] + (5.1000000000000005, 61, 'abcde') + >>> r._shape + (3,) + """ + + if (shape is None or shape == 0): + shape = (-1,) + elif isinstance(shape, (int, long)): + shape = (shape,) + + name = 0 + if isinstance(fd, str): + name = 1 + fd = open(fd, 'rb') + if (offset > 0): + fd.seek(offset, 1) + try: + size = os.fstat(fd.fileno())[stat.ST_SIZE] - fd.tell() + except: + size = os.path.getsize(fd.name) - fd.tell() + + parsed = format_parser(formats, names, titles, aligned) + itemsize = parsed._descr.itemsize + + shapeprod = sb.array(shape).prod() + shapesize = shapeprod*itemsize + if shapesize < 0: + shape = list(shape) + shape[ shape.index(-1) ] = size / -shapesize + shape = tuple(shape) + shapeprod = sb.array(shape).prod() + + nbytes = shapeprod*itemsize + + if nbytes > size: + raise ValueError( + "Not enough bytes left in file for specified shape and type") + + # create the array + _array = recarray(shape, parsed._descr) + nbytesread = fd.readinto(_array.data) + if nbytesread != nbytes: + raise IOError("Didn't read as many bytes as expected") + if name: + fd.close() + + # update swap flag if byteorder does not match + if ((byteorder != _sysbyte) and (byteorder in _byteorders)): + _array.flags.swapped=True + + return _array + + +def array(obj, formats=None, names=None, titles=None, shape=None, + byteorder=_sysbyte, aligned=0, offset=0, strides=None): + + if isinstance(obj, (type(None), str, file)) and (formats is None): + raise ValueError("Must define formats if object is "\ + "None, string, or a file pointer") + + elif obj is None: + if shape is None: + raise ValueError("Must define a shape if obj is None") + return recarray(shape, formats, names=names, titles=titles, + buf=obj, offset=offset, strides=strides, + byteorder=byteorder, aligned=aligned) + elif isinstance(obj, str): + return fromstring(obj, formats, names=names, titles=titles, + shape=shape, byteorder=byteorder, aligned=aligned, + offset=offset) + elif isinstance(obj, (list, tuple)): + if isinstance(obj[0], sb.ndarray): + return fromarrays(obj, formats=formats, names=names, titles=titles, + shape=shape, aligned=aligned) + else: + return fromrecords(obj, formats=formats, names=names, titles=titles, + shape=shape, aligned=aligned) + elif isinstance(obj, recarray): + new = obj.copy() + parsed = format_parser(formats, names, titles, aligned) + new.dtypedescr = parsed._descr + return new + elif isinstance(obj, file): + return fromfile(obj, formats=formats, names=names, titles=titles, + shape=shape, byteorder=byteorder, aligned=aligned, + offset=offset) + else: + raise ValueError("Unknown input type") + + + + |