[Patch] Simplify basic_stringbuf::seekoff

[Paolo Carlini <pcarlini at unitus dot it>]

Hi,

this is the first of two patches affecting basic_stringbuf::seekoff
and seekpos (the other one is more substantial)

Consider, f.i., __endi: when it's actually used, in the last 'if',
it's always equal to _M_in_end; __newoffi, likewise, which depends
on __endi, is used only when __endi is assigned _M_in_end.

Overall, this saves 4 varibles and two 'if', doesn't seem to worsen
that much the clarity.

Tested x86-linux. Ok with you?

Paolo.

/////////
2003-05-30  Paolo Carlini  <pcarlini@unitus.it>

	* include/bits/sstream.tcc (seekoff): Remove four unnecessary
	variables and two 'if', clean up.

diff -urN libstdc++-v3-orig/include/bits/sstream.tcc libstdc++-v3/include/bits/sstream.tcc
--- libstdc++-v3-orig/include/bits/sstream.tcc	2003-05-07 07:01:57.000000000 +0200
+++ libstdc++-v3/include/bits/sstream.tcc	2003-05-30 19:48:31.000000000 +0200
@@ -132,45 +132,32 @@
       if (_M_string.capacity() && (__testin || __testout || __testboth))
 	{
 	  char_type* __beg = __testin ? this->_M_in_beg : this->_M_out_beg;
-	  char_type* __curi = NULL;
-	  char_type* __curo = NULL;
-	  char_type* __endi = NULL;
-	  char_type* __endo = NULL;
-
-	  if (__testin || __testboth)
-	    {
-	      __curi = this->_M_in_cur;
-	      __endi = this->_M_in_end;
-	    }
-	  if (__testout || __testboth)
-	    {
-	      __curo = this->_M_out_cur;
-	      // Due to the resolution of DR169, ios_base::end
-	      // is this->_M_out_lim, not _M_out_end.
-	      __endo = this->_M_out_lim;
-	    }
 
 	  off_type __newoffi = 0;
 	  off_type __newoffo = 0;
 	  if (__way == ios_base::cur)
 	    {
-	      __newoffi = __curi - __beg;
-	      __newoffo = __curo - __beg;
+	      __newoffi = this->_M_in_cur - __beg;
+	      __newoffo = this->_M_out_cur - __beg;
 	    }
 	  else if (__way == ios_base::end)
 	    {
-	      __newoffi = __endi - __beg;
-	      __newoffo = __endo - __beg;
+	      __newoffi = this->_M_in_end - __beg;
+	      // Due to the resolution of DR169, ios_base::end
+	      // is this->_M_out_lim, not _M_out_end.
+	      __newoffo = this->_M_out_lim - __beg;
 	    }
 
 	  if ((__testin || __testboth)
-	      && __newoffi + __off >= 0 && __endi - __beg >= __newoffi + __off)
+	      && __newoffi + __off >= 0 
+	      && this->_M_in_end - __beg >= __newoffi + __off)
 	    {
 	      this->_M_in_cur = __beg + __newoffi + __off;
 	      __ret = pos_type(__newoffi);
 	    }
 	  if ((__testout || __testboth)
-	      && __newoffo + __off >= 0 && __endo - __beg >= __newoffo + __off)
+	      && __newoffo + __off >= 0 
+	      && this->_M_out_lim - __beg >= __newoffo + __off)
 	    {
 	      _M_move_out_cur(__newoffo + __off - (this->_M_out_cur - __beg));
 	      __ret = pos_type(__newoffo);