[Boost-commit] svn:boost r49198 - trunk/boost/asio

Subject: [Boost-commit] svn:boost r49198 - trunk/boost/asio
From: chris_at_[hidden]
Date: 2008-10-09 02:30:17

Author: chris_kohlhoff
Date: 2008-10-09 02:30:16 EDT (Thu, 09 Oct 2008)
New Revision: 49198
URL: http://svn.boost.org/trac/boost/changeset/49198

Log:
Ensure the streambuf's egptr() is kept in sync the pptr(). Use std::memmove
rather than std::rotate to minimise data copying. Avoid unnecessary resizes
of the underlying vector.

Text files modified: 
   trunk/boost/asio/basic_streambuf.hpp |    13 +++++++------                           
   1 files changed, 7 insertions(+), 6 deletions(-)

Modified: trunk/boost/asio/basic_streambuf.hpp
==============================================================================
--- trunk/boost/asio/basic_streambuf.hpp	(original)
+++ trunk/boost/asio/basic_streambuf.hpp	2008-10-09 02:30:16 EDT (Thu, 09 Oct 2008)
@@ -19,6 +19,7 @@
 
 #include <boost/asio/detail/push_options.hpp>
 #include <algorithm>
+#include <cstring>
 #include <limits>
 #include <memory>
 #include <stdexcept>
@@ -96,6 +97,7 @@
     if (pptr() + n > epptr())
       n = epptr() - pptr();
     pbump(static_cast<int>(n));
+    setg(eback(), gptr(), pptr());
   }
 
   /// Move the start of the get area by the specified number of characters.
@@ -151,7 +153,6 @@
   {
     // Get current stream positions as offsets.
     std::size_t gnext = gptr() - &buffer_[0];
-    std::size_t gend = egptr() - &buffer_[0];
     std::size_t pnext = pptr() - &buffer_[0];
     std::size_t pend = epptr() - &buffer_[0];
 
@@ -164,9 +165,8 @@
     // Shift existing contents of get area to start of buffer.
     if (gnext > 0)
     {
-      std::rotate(&buffer_[0], &buffer_[0] + gnext, &buffer_[0] + pend);
-      gend -= gnext;
       pnext -= gnext;
+      std::memmove(&buffer_[0], &buffer_[0] + gnext, pnext);
     }
 
     // Ensure buffer is large enough to hold at least the specified size.
@@ -174,7 +174,8 @@
     {
       if (n <= max_size_ && pnext <= max_size_ - n)
       {
-        buffer_.resize((std::max<std::size_t>)(pnext + n, 1));
+        pend = pnext + n;
+        buffer_.resize((std::max<std::size_t>)(pend, 1));
       }
       else
       {
@@ -183,8 +184,8 @@
     }
 
     // Update stream positions.
-    setg(&buffer_[0], &buffer_[0], &buffer_[0] + gend);
-    setp(&buffer_[0] + pnext, &buffer_[0] + pnext + n);
+    setg(&buffer_[0], &buffer_[0], &buffer_[0] + pnext);
+    setp(&buffer_[0] + pnext, &buffer_[0] + pend);
   }
 
 private: