Fix handling of eof() in streambuffer underflow.

@tomlankhorst has identified a serious bug which affected the
`ilostream` class.  If you opened a large object _as an ilostream,_
and it contained a byte with value `0xff` _at a buffer boundary,_
on a system where `char` is a signed type (such as x86-compatible
systems), then reading of the large object would **mistake the
`0xff` byte for end-of-file** and stop reading prematurely.

NEWS

@@ -1,3 +1,5 @@
+6.4.6
+ - `ilostream` could truncate at `0xff` byte at buffer boundary (#284, #286).
 6.4.5
  - Fixed "const" support in arguments to parameterised/prepared statements.
 6.4.4

VERSION

@@ -1 +1 @@
-6.4.5
+6.4.6

configure

@@ -1,6 +1,6 @@
 #! /bin/sh
 # Guess values for system-dependent variables and create Makefiles.
-# Generated by GNU Autoconf 2.69 for libpqxx 6.4.5.
+# Generated by GNU Autoconf 2.69 for libpqxx 6.4.6.
 #
 # Report bugs to <Jeroen T. Vermeulen>.
 #
@@ -590,8 +590,8 @@ MAKEFLAGS=
 # Identity of this package.
 PACKAGE_NAME='libpqxx'
 PACKAGE_TARNAME='libpqxx'
-PACKAGE_VERSION='6.4.5'
-PACKAGE_STRING='libpqxx 6.4.5'
+PACKAGE_VERSION='6.4.6'
+PACKAGE_STRING='libpqxx 6.4.6'
 PACKAGE_BUGREPORT='Jeroen T. Vermeulen'
 PACKAGE_URL=''
 
@@ -1365,7 +1365,7 @@ if test "$ac_init_help" = "long"; then
   # Omit some internal or obsolete options to make the list less imposing.
   # This message is too long to be a string in the A/UX 3.1 sh.
   cat <<_ACEOF
-\`configure' configures libpqxx 6.4.5 to adapt to many kinds of systems.
+\`configure' configures libpqxx 6.4.6 to adapt to many kinds of systems.
 
 Usage: $0 [OPTION]... [VAR=VALUE]...
 
@@ -1436,7 +1436,7 @@ fi
 
 if test -n "$ac_init_help"; then
   case $ac_init_help in
-     short | recursive ) echo "Configuration of libpqxx 6.4.5:";;
+     short | recursive ) echo "Configuration of libpqxx 6.4.6:";;
    esac
   cat <<\_ACEOF
 
@@ -1564,7 +1564,7 @@ fi
 test -n "$ac_init_help" && exit $ac_status
 if $ac_init_version; then
   cat <<\_ACEOF
-libpqxx configure 6.4.5
+libpqxx configure 6.4.6
 generated by GNU Autoconf 2.69
 
 Copyright (C) 2012 Free Software Foundation, Inc.
@@ -2054,7 +2054,7 @@ cat >config.log <<_ACEOF
 This file contains any messages produced by compilers while
 running configure, to aid debugging if configure makes a mistake.
 
-It was created by libpqxx $as_me 6.4.5, which was
+It was created by libpqxx $as_me 6.4.6, which was
 generated by GNU Autoconf 2.69.  Invocation command line was
 
   $ $0 $@
@@ -4162,7 +4162,7 @@ fi
 
 # Define the identity of the package.
  PACKAGE='libpqxx'
- VERSION='6.4.5'
+ VERSION='6.4.6'
 
 
 cat >>confdefs.h <<_ACEOF
@@ -18778,7 +18778,7 @@ cat >>$CONFIG_STATUS <<\_ACEOF || ac_write_fail=1
 # report actual input values of CONFIG_FILES etc. instead of their
 # values after options handling.
 ac_log="
-This file was extended by libpqxx $as_me 6.4.5, which was
+This file was extended by libpqxx $as_me 6.4.6, which was
 generated by GNU Autoconf 2.69.  Invocation command line was
 
   CONFIG_FILES    = $CONFIG_FILES
@@ -18844,7 +18844,7 @@ _ACEOF
 cat >>$CONFIG_STATUS <<_ACEOF || ac_write_fail=1
 ac_cs_config="`$as_echo "$ac_configure_args" | sed 's/^ //; s/[\\""\`\$]/\\\\&/g'`"
 ac_cs_version="\\
-libpqxx config.status 6.4.5
+libpqxx config.status 6.4.6
 configured by $0, generated by GNU Autoconf 2.69,
   with options \\"\$ac_cs_config\\"
 

include/pqxx/largeobject.hxx

@@ -434,11 +434,12 @@ protected:
   virtual int_type underflow() override
   {
     if (this->gptr() == nullptr) return EoF();
-    char *const eb = this->eback();
-    const int_type res(static_cast<int_type>(
-	AdjustEOF(m_obj.cread(this->eback(), m_bufsize))));
-    this->setg(eb, eb, eb + ((res==EoF()) ? 0 : res));
-    return ((res == 0) or (res == EoF())) ? EoF() : *eb;
+    auto *const eb{this->eback()};
+    auto const res = AdjustEOF(
+	m_obj.cread(this->eback(), static_cast<std::size_t>(m_bufsize)));
+    this->setg(
+	eb, eb, eb + (res == EoF() ? 0 : static_cast<std::size_t>(res)));
+    return (res == EoF() || res == 0) ? EoF() : traits_type::to_int_type(*eb);
   }
 
 private:

include/pqxx/version.hxx

@@ -14,7 +14,7 @@
 #include "pqxx/compiler-internal-pre.hxx"
 
 /// Full libpqxx version string.
-#define PQXX_VERSION "6.4.5"
+#define PQXX_VERSION "6.4.6"
 /// Library ABI version.
 #define PQXX_ABI "6.4"