[v3, 3.2 and 3.1] Fix replace regression wrt 2.95.x and 3.0.x

[Paolo Carlini <pcarlini at unitus dot it>]

Hi,

as I did already anticipate yesterday, the fix for __throw_length_error 
in basic_string::replace turns out to be quite critical, since not only 
tightens the check but avoid throwing in the /wrong/ situations. I have 
added therefore a testcase which represents a regression wrt 2.95.x and 
3.0.x.

I really would like to have it in 3.1.0 too, if still possible.

Tested i686-pc-linux-gnu, Ok for both?

Ciao, Paolo.

////////////////////////

2002-04-26  Paolo Carlini  <pcarlini@unitus.it>

        * include/bits/basic_string.h (replace(__pos, __n1, __s, __n2):
        Fix and tighten __throw_length_error check.
        * testsuite/21_strings/replace.cc (test05): New.
        * testsuite/21_strings/replace.cc (test02, test03, test04): Tweak.

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    2002-04-16 
04:29:20.000000000 +0200
+++ libstdc++-v3/include/bits/basic_string.h    2002-04-23 
23:55:33.000000000 +0200
@@ -642,10 +642,10 @@
     const size_type __size = this->size();
      if (__pos > __size)
       __throw_out_of_range("basic_string::replace");
-    if (__size - __n1 > this->max_size() - __n2)
-      __throw_length_error("basic_string::replace");
     const bool __testn1 = __n1 < __size - __pos;
     const size_type __foldn1 = __testn1 ? __n1 : __size - __pos;
+    if (__size - __foldn1 > this->max_size() - __n2)
+      __throw_length_error("basic_string::replace");
     if (_M_rep()->_M_is_shared() || less<const _CharT*>()(__s, _M_data())
         || less<const _CharT*>()(_M_data() + __size, __s))
       return _M_replace_safe(_M_ibegin() + __pos,
diff -urN libstdc++-v3-orig/testsuite/21_strings/replace.cc 
libstdc++-v3/testsuite/21_strings/replace.cc
--- libstdc++-v3-orig/testsuite/21_strings/replace.cc    2002-04-02 
14:07:07.000000000 +0200
+++ libstdc++-v3/testsuite/21_strings/replace.cc    2002-04-26 
12:34:11.000000000 +0200
@@ -84,6 +84,7 @@
 void
 test02()
 {
+  bool test = true;
   const char* strlit = "../the long pier/Hanalei Bay/Kauai/Hawaii";
   std::string aux = strlit;
   aux.replace(aux.begin()+5, aux.begin()+20,
@@ -100,6 +101,7 @@
 void
 test03()
 {
+  bool test = true;
   const char* title01 = "nine types of ambiguity";
   const char* title02 = "ultra";
   std::string str01 = title01;
@@ -145,6 +147,7 @@
 void
 test04()
 {
+  bool test = true;
   std::string str01 = "geogaddi";
   std::string str02;
 
@@ -175,11 +178,25 @@
   VERIFY(str02 == "geogaddi");
 }
 
+// We wrongly used __n1 instead of __foldn1 in the length_error
+// check at the beginning of replace(__pos, __n1, __s, __n2)
+void
+test05()
+{
+  bool test = true;
+  std::string str01 = "londinium";
+  std::string str02 = "cydonia";
+
+  str01.replace(0, 20, str02.c_str(), 3);
+  VERIFY(str01 == "cyd");
+}
+
 int main()
 {
   test01();
   test02();
   test03();
   test04();
+  test05();
   return 0;
 }