[pypy-commit] pypy use-file-star-for-file: use alloc_buffer to avoid extra copy when possible in read
bdkearns
noreply at buildbot.pypy.org
Thu Sep 11 13:13:00 CEST 2014
Author: Brian Kearns <bdkearns at gmail.com>
Branch: use-file-star-for-file
Changeset: r73459:fd6110e214ca
Date: 2014-09-11 07:11 -0400
http://bitbucket.org/pypy/pypy/changeset/fd6110e214ca/
Log: use alloc_buffer to avoid extra copy when possible in read
diff --git a/rpython/rlib/rfile.py b/rpython/rlib/rfile.py
--- a/rpython/rlib/rfile.py
+++ b/rpython/rlib/rfile.py
@@ -375,10 +375,10 @@
s = StringBuilder()
buffersize = size if size >= 0 else self._new_buffersize(0)
remainsize = buffersize
- buf = lltype.malloc(rffi.CCHARP.TO, remainsize, flavor='raw')
+ raw_buf, gc_buf = rffi.alloc_buffer(remainsize)
try:
while True:
- chunksize = intmask(self._fread(buf, remainsize, ll_file))
+ chunksize = intmask(self._fread(raw_buf, remainsize, ll_file))
interrupted = (c_ferror(ll_file) and
rposix.get_errno() == errno.EINTR)
if interrupted:
@@ -394,7 +394,11 @@
if s.getlength() > 0 and rposix.get_errno() == errno.EAGAIN:
break
raise _from_errno(IOError)
- s.append_charpsize(buf, chunksize)
+ elif chunksize == size:
+ # we read everything in one call, try to avoid copy
+ # (remainsize == size if chunksize == size)
+ return rffi.str_from_buffer(raw_buf, gc_buf, remainsize, size)
+ s.append_charpsize(raw_buf, chunksize)
if chunksize < remainsize and not interrupted:
c_clearerr(ll_file)
break
@@ -402,10 +406,10 @@
break
buffersize = self._new_buffersize(buffersize)
remainsize = buffersize - s.getlength()
- lltype.free(buf, flavor='raw')
- buf = lltype.malloc(rffi.CCHARP.TO, remainsize, flavor='raw')
+ rffi.keep_buffer_alive_until_here(raw_buf, gc_buf)
+ raw_buf, gc_buf = rffi.alloc_buffer(remainsize)
finally:
- lltype.free(buf, flavor='raw')
+ rffi.keep_buffer_alive_until_here(raw_buf, gc_buf)
return s.build()
def _readline1(self, raw_buf):
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