This should be faster.
This means:
(1) "for line in file:" won't work if the xreadlines module can't be
imported.
(2) The body of "for line in file:" shouldn't use the file directly;
the effects (e.g. of file.readline(), file.seek() or even
file.tell()) would be undefined because of the buffering that goes
on in the xreadlines module.
sees it (test_iter.py is unchanged).
- Added a tp_iternext slot, which calls the iterator's next() method;
this is much faster for built-in iterators over built-in types
such as lists and dicts, speeding up pybench's ForLoop with about
25% compared to Python 2.1. (Now there's a good argument for
iterators. ;-)
- Renamed the built-in sequence iterator SeqIter, affecting the C API
functions for it. (This frees up the PyIter prefix for generic
iterator operations.)
- Added PyIter_Check(obj), which checks that obj's type has a
tp_iternext slot and that the proper feature flag is set.
- Added PyIter_Next(obj) which calls the tp_iternext slot. It has a
somewhat complex return condition due to the need for speed: when it
returns NULL, it may not have set an exception condition, meaning
the iterator is exhausted; when the exception StopIteration is set
(or a derived exception class), it means the same thing; any other
exception means some other error occurred.
- In _portable_ftell(), try fgetpos() before ftello() and ftell64().
I ran into a situation on a 64-bit capable Linux where the C
library's ftello() and ftell64() returned negative numbers despite
fpos_t and off_t both being 64-bit types; fgetpos() did the right
thing.
- Define a new typedef, Py_off_t, which is either fpos_t or off_t,
depending on which one is 64 bits. This removes the need for a lot
of #ifdefs later on. (XXX Should this be moved to pyport.h? That
file currently seems oblivious to large fille support, so for now
I'll leave it here where it's needed.)
simpler if we use fgetpos and fsetpos, rather than trying to mess with
platform-specific TELL64 alternatives.
Of course, this hasn't been tested on a 64-bit platform, so I may have
to withdraw this -- but I'm hopeful, and Trent Mick supports this
patch!
faster than the other. Should be faster for Mark Favas's 254-character
mail log lines, and *is* 3-4% quicker for my test case with much shorter
lines (but they're typical of *my* text files, and I'm tired of optimizing
for everyone else at my expense <wink> -- in fact, the only one who loses
here is Guido ...).
Tim discovered another "bug" in my get_line() code: while the comments
said that n<0 was invalid, it was in fact still called with n<0 (when
PyFile_GetLine() was called with n<0). In that case fortunately
executed the same code as for n==0.
Changed the comment to admit this fact, and changed Tim's MS speed
hack code to use 'n <= 0' as the criteria for the speed hack.
code duplication is to let us get away without a realloc whenever possible;
boosted the init buf size (the cutoff at which we *can* get away without
a realloc) from 100 to 200 so that more files can enjoy this boost; and
allowed other threads to run in all cases. The last two cost something,
but not significantly: in my fat test case, less than a 1% slowdown total.
Since my test case has a great many short lines, that's probably the worst
slowdown, too. While the logic barely changed, there were lots of edits.
This also gets rid of the reference to fp->_cnt, so the last platform
assumption being made here is that fgets doesn't overwrite bytes
capriciously (== beyond the terminating null byte it must write).
variant that never needs to "search from the right".
Also fixed unlikely memory leak in get_line, if string size overflows INTMAX.
Also new std test test_bufio to make sure .readline() works.
realized that this behavior is already present in PyFile_GetLine(),
which is the only place that needs it. A little refactoring of that
function made get_line_raw() redundant.
- The raw_input() functionality is moved to a separate function.
- Drop GNU getline() in favor of getc_unlocked(), which exists on more
platforms (and is even a tad faster on my system).
Add definitions of INT_MAX and LONG_MAX to pyport.h.
Remove includes of limits.h and conditional definitions of INT_MAX
and LONG_MAX elsewhere.
This closes SourceForge patch #101659 and bug #115323.
file.writelines() now tries to emulate the behaviour of file.write()
as closely as possible. Due to the problems with releasing the
interpreter lock the solution isn't exactly optimal, but still better
than not supporting the file.write() semantics at all.
The common technique for printing out a pointer has been to cast to a long
and use the "%lx" printf modifier. This is incorrect on Win64 where casting
to a long truncates the pointer. The "%p" formatter should be used instead.
The problem as stated by Tim:
> Unfortunately, the C committee refused to define what %p conversion "looks
> like" -- they explicitly allowed it to be implementation-defined. Older
> versions of Microsoft C even stuck a colon in the middle of the address (in
> the days of segment+offset addressing)!
The result is that the hex value of a pointer will maybe/maybe not have a 0x
prepended to it.
Notes on the patch:
There are two main classes of changes:
- in the various repr() functions that print out pointers
- debugging printf's in the various thread_*.h files (these are why the
patch is large)
Closes SourceForge patch #100505.
For more comments, read the patches@python.org archives.
For documentation read the comments in mymalloc.h and objimpl.h.
(This is not exactly what Vladimir posted to the patches list; I've
made a few changes, and Vladimir sent me a fix in private email for a
problem that only occurs in debug mode. I'm also holding back on his
change to main.c, which seems unnecessary to me.)
This (1) avoids thread unsafety whereby another thread could zap the
list while we were using it, and (2) now supports writing arbitrary
sequences of strings.
Guido van Rossum
Tim Peters
Fred Drake
Andrew M. Kuchling
Marc-André Lemburg
Jack Jansen
Trent Mick