[Python-checkins] cpython: Issue #15381: Optimized line reading in io.BytesIO.
serhiy.storchaka
python-checkins at python.org
Thu Aug 14 21:34:56 CEST 2014
http://hg.python.org/cpython/rev/601045ceff94
changeset: 92096:601045ceff94
user: Serhiy Storchaka <storchaka at gmail.com>
date: Thu Aug 14 22:26:38 2014 +0300
summary:
Issue #15381: Optimized line reading in io.BytesIO.
files:
Misc/NEWS | 2 +
Modules/_io/bytesio.c | 54 ++++++++++++++----------------
2 files changed, 28 insertions(+), 28 deletions(-)
diff --git a/Misc/NEWS b/Misc/NEWS
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -115,6 +115,8 @@
Library
-------
+- Issue #15381: Optimized line reading in io.BytesIO.
+
- Issue #20729: Restored the use of lazy iterkeys()/itervalues()/iteritems()
in the mailbox module.
diff --git a/Modules/_io/bytesio.c b/Modules/_io/bytesio.c
--- a/Modules/_io/bytesio.c
+++ b/Modules/_io/bytesio.c
@@ -81,31 +81,28 @@
object. Returns the length between the current position to the
next newline character. */
static Py_ssize_t
-get_line(bytesio *self, char **output)
+scan_eol(bytesio *self, Py_ssize_t len)
{
- char *n;
- const char *str_end;
- Py_ssize_t len;
+ const char *start, *n;
+ Py_ssize_t maxlen;
assert(self->buf != NULL);
/* Move to the end of the line, up to the end of the string, s. */
- str_end = self->buf + self->string_size;
- for (n = self->buf + self->pos;
- n < str_end && *n != '\n';
- n++);
+ start = self->buf + self->pos;
+ maxlen = self->string_size - self->pos;
+ if (len < 0 || len > maxlen)
+ len = maxlen;
- /* Skip the newline character */
- if (n < str_end)
- n++;
-
- /* Get the length from the current position to the end of the line. */
- len = n - (self->buf + self->pos);
- *output = self->buf + self->pos;
-
+ if (len) {
+ n = memchr(start, '\n', len);
+ if (n)
+ /* Get the length from the current position to the end of
+ the line. */
+ len = n - start + 1;
+ }
assert(len >= 0);
assert(self->pos < PY_SSIZE_T_MAX - len);
- self->pos += len;
return len;
}
@@ -477,14 +474,10 @@
return NULL;
}
- n = get_line(self, &output);
+ n = scan_eol(self, size);
- if (size >= 0 && size < n) {
- size = n - size;
- n -= size;
- self->pos -= size;
- }
-
+ output = self->buf + self->pos;
+ self->pos += n;
return PyBytes_FromStringAndSize(output, n);
}
@@ -528,7 +521,9 @@
if (!result)
return NULL;
- while ((n = get_line(self, &output)) != 0) {
+ output = self->buf + self->pos;
+ while ((n = scan_eol(self, -1)) != 0) {
+ self->pos += n;
line = PyBytes_FromStringAndSize(output, n);
if (!line)
goto on_error;
@@ -540,6 +535,7 @@
size += n;
if (maxsize > 0 && size >= maxsize)
break;
+ output += n;
}
return result;
@@ -636,16 +632,18 @@
static PyObject *
bytesio_iternext(bytesio *self)
{
- char *next;
+ const char *next;
Py_ssize_t n;
CHECK_CLOSED(self, NULL);
- n = get_line(self, &next);
+ n = scan_eol(self, -1);
- if (!next || n == 0)
+ if (n == 0)
return NULL;
+ next = self->buf + self->pos;
+ self->pos += n;
return PyBytes_FromStringAndSize(next, n);
}
--
Repository URL: http://hg.python.org/cpython
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