Date: Thu, 20 May 2004 14:47:31 +0100 From: "Jonathan Wakely" <jwakely@mintel.com> To: FreeBSD-gnats-submit@FreeBSD.org, freebsd-bugs@FreeBSD.org Subject: Re: misc/66941: Unacceptable stringstream performance Message-ID: <80256E9A.004BF36B.00@notes03.mintel.co.uk>
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[-- Attachment #1 --]
This is the patch we've been using:
(See attached file: sstream.patch)
[-- Attachment #2 --]
--- /usr/include/g++/sstream.orig Thu Feb 12 05:52:21 2004
+++ /usr/include/g++/sstream Thu May 20 10:28:03 2004
@@ -45,7 +45,7 @@
explicit
stringbuf(int which=ios::in|ios::out)
: streambuf(), mode(static_cast<ios::open_mode>(which)),
- stream(NULL), stream_len(0)
+ stream(NULL), stream_len(0), stream_capacity(0)
{
stringbuf_init();
}
@@ -53,7 +53,7 @@
explicit
stringbuf(const string &str, int which=ios::in|ios::out)
: streambuf(), mode(static_cast<ios::open_mode>(which)),
- stream(NULL), stream_len(0)
+ stream(NULL), stream_len(0), stream_capacity(0)
{
if (mode & (ios::in|ios::out))
{
@@ -83,8 +83,8 @@
str(const string& str)
{
delete[] stream;
- stream_len = str.size();
- stream = new char_type[stream_len];
+ stream_capacity = stream_len = str.size();
+ stream = new char_type[stream_capacity];
str.copy(stream, stream_len);
stringbuf_init();
}
@@ -105,12 +105,15 @@
{
if (c != EOF)
{
- streamsize old_stream_len = stream_len;
+ if (stream_len >= stream_capacity)
+ {
+ stream_capacity = 2 * stream_len + 100;
+ char_type* new_stream = new char_type[stream_capacity];
+ memcpy(new_stream, stream, stream_len);
+ delete[] stream;
+ stream = new_stream;
+ }
stream_len += 1;
- char_type* new_stream = new char_type[stream_len];
- memcpy(new_stream, stream, old_stream_len);
- delete[] stream;
- stream = new_stream;
stringbuf_sync(gptr()-eback(), pptr()-pbase());
sputc(c);
res = c;
@@ -225,6 +228,7 @@
ios::open_mode mode;
char_type* stream;
streamsize stream_len;
+ streamsize stream_capacity;
};
class istringstream : public istream {
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