Re: [Patch] Batch of basic_string correctness and performance work

[Paolo Carlini <pcarlini at suse dot de>]

Paolo Carlini wrote:

> That said, all those append (and operator+=), in the present form 
> perform much better anyway, also if not-inlined (see, f.i., 
> append(const _CharT*, size_type) or, better example, append(const 
> basic_string&, size_type, size_type), which I purposedly kept 
> off-line), therefore, please provide a little bit of evidence that one 
> of your applications would take advantage from moving the functions 
> out of line and I will happily do that!

To give you an idea, this is what happen performance-wise on the ubenchmarks
if I move out of line both append(size_type __n, _CharT __c) (append(char)
actually means append(1, c)) and append(const basic_string&), at issue (I
think push_back and operator+=(_CharT) are not seriously in discussion):

current
-------
Execution time of 10000000 string::append(char) calls: 0.14 sec.
Execution time of 10000000 string::append(const string&) calls: 0.14 sec.

current + out of line
---------------------
Execution time of 10000000 string::append(char) calls: 0.24 sec.
Execution time of 10000000 string::append(const string&) calls: 0.23 sec.

old
---
Execution time of 10000000 string::append(char) calls: 0.26 sec.
Execution time of 10000000 string::append(const string&) calls: 0.49 sec.

Please, test a bit the attached and provide some feedback at your ease,
we have still a good amount of time before 4.0.0...

Paolo.

//////////////
diff -urN libstdc++-v3-orig/include/bits/basic_string.h libstdc++-v3/include/bits/basic_string.h
--- libstdc++-v3-orig/include/bits/basic_string.h	2004-10-24 10:35:29.000000000 +0200
+++ libstdc++-v3/include/bits/basic_string.h	2004-10-25 23:23:09.000000000 +0200
@@ -776,19 +776,7 @@
        *  @return  Reference to this string.
        */
       basic_string&
-      append(const basic_string& __str)
-      {
-	const size_type __size = __str.size();
-	if (__size)
-	  {
-	    const size_type __len = __size + this->size();
-	    if (__len > this->capacity() || _M_rep()->_M_is_shared())
-	      this->reserve(__len);
-	    _M_copy(_M_data() + this->size(), __str._M_data(), __size);
-	    _M_rep()->_M_set_length_and_sharable(__len);
-	  }
-	return *this;
-      }
+      append(const basic_string& __str);
 
       /**
        *  @brief  Append a substring.
@@ -835,19 +823,7 @@
        *  Appends n copies of c to this string.
        */
       basic_string&
-      append(size_type __n, _CharT __c)
-      {
-	if (__n)
-	  {
-	    _M_check_length(size_type(0), __n, "basic_string::append");	  
-	    const size_type __len = __n + this->size();
-	    if (__len > this->capacity() || _M_rep()->_M_is_shared())
-	      this->reserve(__len);
-	    _M_assign(_M_data() + this->size(), __n, __c);
-	    _M_rep()->_M_set_length_and_sharable(__len);
-	  }
-	return *this;
-      }
+      append(size_type __n, _CharT __c);
 
       /**
        *  @brief  Append a range of characters.
diff -urN libstdc++-v3-orig/include/bits/basic_string.tcc libstdc++-v3/include/bits/basic_string.tcc
--- libstdc++-v3-orig/include/bits/basic_string.tcc	2004-10-25 12:36:56.000000000 +0200
+++ libstdc++-v3/include/bits/basic_string.tcc	2004-10-25 23:22:57.000000000 +0200
@@ -264,6 +264,40 @@
   template<typename _CharT, typename _Traits, typename _Alloc>
     basic_string<_CharT, _Traits, _Alloc>&
     basic_string<_CharT, _Traits, _Alloc>::
+    append(size_type __n, _CharT __c)
+    {
+      if (__n)
+	{
+	  _M_check_length(size_type(0), __n, "basic_string::append");	  
+	  const size_type __len = __n + this->size();
+	  if (__len > this->capacity() || _M_rep()->_M_is_shared())
+	    this->reserve(__len);
+	  _M_assign(_M_data() + this->size(), __n, __c);
+	  _M_rep()->_M_set_length_and_sharable(__len);
+	}
+      return *this;
+    }
+
+  template<typename _CharT, typename _Traits, typename _Alloc>
+    basic_string<_CharT, _Traits, _Alloc>&
+    basic_string<_CharT, _Traits, _Alloc>::
+    append(const basic_string& __str)
+    {
+      const size_type __size = __str.size();
+      if (__size)
+	{
+	  const size_type __len = __size + this->size();
+	  if (__len > this->capacity() || _M_rep()->_M_is_shared())
+	    this->reserve(__len);
+	  _M_copy(_M_data() + this->size(), __str._M_data(), __size);
+	  _M_rep()->_M_set_length_and_sharable(__len);
+	}
+      return *this;
+    }
+
+  template<typename _CharT, typename _Traits, typename _Alloc>
+    basic_string<_CharT, _Traits, _Alloc>&
+    basic_string<_CharT, _Traits, _Alloc>::
     append(const _CharT* __s, size_type __n)
     {
       __glibcxx_requires_string_len(__s, __n);