data formats. The _xdr module is no longer used, since struct
supports the required IEEE floats and doubles.
(I have one doubt about not using _xdr. The struct module doesn't
handle Inf, NaN and gradual underflow correctly. If the _xdr module
does these things better, it may still have a (small) competitive
advantage. On the other hand, since not all platforms support IEEE
floating point, it's not clear that it would be a good idea to ever
transfer Inf or NaNs. Gradual underflow can be fixed in the struct
module.
module. (Small problem: struct.pack() won't deal with the Python long
ints returned by struct.unpack() for the 'L' format. Worked around
that for now.)
-- The whole implementation is now more table-driven.
-- Unsigned integers. Format characters 'B', 'H', 'I' and 'L'
mean unsigned byte, short, int and long. For 'I' and 'L', the return
value is a Python long integer if a Python plain integer can't
represent the required range (note: this is dependent on the size of
the relevant C types only, not of the sign of the actual value).
-- A new format character 's' packs/unpacks a string. When given a
count prefix, this is the size of the string, not a repeat count like
for the other format characters; e.g. '10s' means a single 10-byte
string, while '10c' means 10 characters. For packing, the string is
truncated or padded with null bytes as appropriate to make it fit.
For unpacking, the resulting string always has exactly the specified
number of bytes. As a special case, '0s' means a single, empty
string (while '0c' means 0 characters).
-- Various byte order options. The first character of the format
string determines the byte order, size and alignment, as follows:
First character Byte order size and alignment
'@' native native
'=' native standard
'<' little-endian standard
'>' big-endian standard
'!' network (= big-endian) standard
If the first character is not one of these, '@' is assumed.
Native byte order is big-endian or little-endian, depending on the
host system (e.g. Motorola and Sun are big-endian; Intel and DEC are
little-endian).
Native size and alignment are determined using the C compiler's sizeof
expression. This is always combined with native byte order.
Standard size and alignment are as follows: no alignment is required
for any type (so you have to use pad bytes); short is 2 bytes; int and
long are 4 bytes. In this mode, there is no support for float and
double.
Note the difference between '@' and '=': both use native byte order,
but the size and alignment of the latter is standardized.
The form '!' is available for those poor souls who can't remember
whether network byte order is big-endian or little-endian.
There is no way to indicate non-native byte order (i.e. force
byte-swapping); use the appropriate choice of '<' or '>'.
all the modules attributes are present and creates a small criss-cross
window for 5 seconds (example from the documentation :-) A more
comprehensive test would probably be useful... but maybe overkill.
test_rotor.py: New test of the rotor module.
test_*: converted to the new test harness. GvR note! test_signal.py
works interatively (i.e. when verbose=1) but does not work inside the
test harness. It must be a timing issue, but I haven't figured it out
yet.
test_*: converted to the new test harness. GvR note! test_signal.py
works interatively (i.e. when verbose=1) but does not work inside the
test harness. It must be a timing issue, but I haven't figured it out
yet.
non-checked error return values, and where appropriate,
PyArg_ParseTuple() style argument parsing.
I also changed some function names and converted all malloc/free calls
to PyMem_NEW/PyMem_DEL.
Some stylistic changes and formatting standardization.
take an optional string key, but if key is not given, the method does
nothing! In the rewrite (see upcoming check-in), I left things this
way, but here I document that this is the case.
'verbose' flag ala GvR updated test harness architecture.
Old way:
verbose = 0
if __name__ == '__main__':
verbose = 1
New way:
from test_support import verbose
Some other small readablility and functionality updates.
Guido van Rossum
Barry Warsaw
Fred Drake
Roger E. Masse
Jack Jansen