re PR libstdc++/6746 (ifstream::readsome() always returns zero)

2002-11-11  Benjamin Kosnik  <bkoz@redhat.com>

        PR libstdc++/6746
        * include/bits/fstream.tcc (filebuf::open): Set input pointers.
	* config/io/basic_file_stdio.cc (__basic_file::_M_open_mode): Set
	__p_mode as well.
	(__basic_file::open): Set to non-block for input.
	* testsuite/27_io/istream_unformatted.cc (test12): Add.
	(test13): Same.

From-SVN: r59030

libstdc++-v3/ChangeLog

+2002-11-11  Benjamin Kosnik  <bkoz@redhat.com>
+ 
+        PR libstdc++/6746
+        * include/bits/fstream.tcc (filebuf::open): Set input pointers.
+	* config/io/basic_file_stdio.cc (__basic_file::_M_open_mode): Set
+	__p_mode as well.
+	(__basic_file::open): Set to non-block for input.
+	* testsuite/27_io/istream_unformatted.cc (test12): Add.
+	(test13): Same.
+	
 2002-11-11  Jonathan Wakely <redi@gcc.gnu.org>
 
 	* docs/html/17_intro/howto.html: Make "chapter 22 notes" a link.

libstdc++-v3/config/io/basic_file_stdio.cc

@@ -32,6 +32,7 @@
 //
 
 #include <bits/basic_file.h>
+#include <fcntl.h>
 
 namespace std 
 {
@@ -43,8 +44,8 @@ namespace std
   { this->close(); }
       
   void 
-  __basic_file<char>::_M_open_mode(ios_base::openmode __mode, int&, int&, 
-				   char* __c_mode)
+  __basic_file<char>::_M_open_mode(ios_base::openmode __mode, int& __p_mode, 
+				   int&, char* __c_mode)
   {  
     bool __testb = __mode & ios_base::binary;
     bool __testi = __mode & ios_base::in;
@@ -52,18 +53,39 @@ namespace std
     bool __testt = __mode & ios_base::trunc;
     bool __testa = __mode & ios_base::app;
       
+    // Set __c_mode for use in fopen.
+    // Set __p_mode for use in open.
     if (!__testi && __testo && !__testt && !__testa)
-      strcpy(__c_mode, "w");
+      {
+	strcpy(__c_mode, "w");
+	__p_mode = (O_WRONLY | O_CREAT);
+      }
     if (!__testi && __testo && !__testt && __testa)
-      strcpy(__c_mode, "a");
+      {
+	strcpy(__c_mode, "a");
+	__p_mode |=  O_WRONLY | O_CREAT | O_APPEND;
+      }
     if (!__testi && __testo && __testt && !__testa)
-      strcpy(__c_mode, "w");
+      {
+	strcpy(__c_mode, "w");
+	__p_mode |=  O_WRONLY | O_CREAT | O_TRUNC;
+      }
+
     if (__testi && !__testo && !__testt && !__testa)
-      strcpy(__c_mode, "r");
+      {
+	strcpy(__c_mode, "r");
+	__p_mode |=  O_RDONLY | O_NONBLOCK;
+      }
     if (__testi && __testo && !__testt && !__testa)
-      strcpy(__c_mode, "r+");
+      {
+	strcpy(__c_mode, "r+");
+	__p_mode |=  O_RDWR | O_CREAT;
+      }
     if (__testi && __testo && __testt && !__testa)
-      strcpy(__c_mode, "w+");
+      {
+	strcpy(__c_mode, "w+");
+	__p_mode |=  O_RDWR | O_CREAT | O_TRUNC;
+      }
     if (__testb)
       strcat(__c_mode, "b");
   }
@@ -128,6 +150,11 @@ namespace std
 	if ((_M_cfile = fopen(__name, __c_mode)))
 	  {
 	    _M_cfile_created = true;
+
+	    // Set input to nonblocking for fifos.
+	    if (__mode & ios_base::in)
+	      fcntl(this->fd(), F_SETFL, O_NONBLOCK);
+
 	    __ret = this;
 	  }
       }

libstdc++-v3/include/bits/fstream.tcc

@@ -90,11 +90,21 @@ namespace std
 	    {
 	      _M_allocate_internal_buffer();
 	      _M_mode = __mode;
+
+	      // Setup initial position of buffer.
 	      _M_set_indeterminate();
 
+	      // Set input buffer to something real.
+	      // NB: Must open in non-blocking way to do this, or must
+	      // set the initial position in a different manner than
+	      // using underflow.
+ 	      if (__mode & ios_base::in && _M_buf_allocated)
+ 		this->underflow();
+	      
 	      if ((__mode & ios_base::ate)
 		  && this->seekoff(0, ios_base::end, __mode) < 0)
 		this->close();
+
 	      __ret = this;
 	    }
 	}

libstdc++-v3/testsuite/27_io/istream_unformatted.cc

@@ -569,7 +569,54 @@ void test11()
   VERIFY(istr.rdstate() == ios_base::goodbit);
 }
 
-
+// libstdc++/6746   
+void test12()
+{
+  using namespace std;
+  bool test = true;
+  streamsize sum = 0;
+  istringstream iss("shamma shamma");
+      
+  // test01
+  size_t i = iss.rdbuf()->in_avail();
+  VERIFY( i != 0 );
+    
+  // test02
+  streamsize extracted;
+  do
+    {
+      char buf[1024];
+      extracted = iss.readsome(buf, sizeof buf);
+      sum += extracted;
+    }
+  while (iss.good() && extracted);
+  VERIFY( sum != 0 );  
+}
+    
+// libstdc++/6746   
+void test13()
+{
+  using namespace std;
+  bool test = true;
+  streamsize sum = 0;
+  ifstream ifs("istream_unformatted-1.tst");
+      
+  // test01
+  size_t i = ifs.rdbuf()->in_avail();
+  VERIFY( i != 0 );
+    
+  // test02
+  streamsize extracted;
+  do
+    {
+      char buf[1024];
+      extracted = ifs.readsome(buf, sizeof buf);
+      sum += extracted;
+    }
+  while (ifs.good() && extracted);
+  VERIFY( sum != 0 );  
+}
+ 
 int 
 main()
 {
@@ -584,5 +631,9 @@ main()
   test09();
   test10();
   test11();
+
+  test12();
+  test13();
+
   return 0;
 }