Merge pull request #191 from grrtrr/issue_190

vectorstream: support file sizes larger than INT_MAX

include/boost/interprocess/streams/vectorstream.hpp

@@ -52,6 +52,7 @@
 #include <istream>
 #include <ostream>
 #include <string>    // char traits
+#include <climits>   // INT_MAX
 #include <cstddef>   // ptrdiff_t
 #include <boost/interprocess/interprocess_fwd.hpp>
 #include <boost/assert.hpp>
@@ -138,9 +139,9 @@ class basic_vectorbuf
          if(m_vect.size() > high_pos){
             m_vect.resize(high_pos);
             //But we must update end write pointer because vector size is now shorter
-            int old_pos = (int)(base_t::pptr() - base_t::pbase());
+            off_type old_pos = base_t::pptr() - base_t::pbase();
             const_cast<basic_vectorbuf*>(this)->base_t::setp(old_ptr, old_ptr + high_pos);
-            const_cast<basic_vectorbuf*>(this)->base_t::pbump(old_pos);
+            const_cast<basic_vectorbuf*>(this)->pbump(old_pos);
          }
       }
       return m_vect;
@@ -152,14 +153,14 @@ class basic_vectorbuf
    void reserve(typename vector_type::size_type size)
    {
       if (this->m_mode & std::ios_base::out && size > m_vect.size()){
-         typename vector_type::difference_type write_pos = base_t::pptr() - base_t::pbase();
-         typename vector_type::difference_type read_pos  = base_t::gptr() - base_t::eback();
+         off_type write_pos = base_t::pptr() - base_t::pbase();
+         off_type read_pos  = base_t::gptr() - base_t::eback();
          //Now update pointer data
          m_vect.reserve(size);
          this->initialize_pointers();
-         base_t::pbump((int)write_pos);
+         this->pbump(write_pos);
          if(this->m_mode & std::ios_base::in){
-            base_t::gbump((int)read_pos);
+            base_t::setg(base_t::eback(), base_t::eback() + read_pos, base_t::egptr());
          }
       }
    }
@@ -189,7 +190,7 @@ class basic_vectorbuf
       // The initial write position is the beginning of the vector.
       if(m_mode & std::ios_base::out){
          //First get real size
-         int real_size = (int)m_vect.size();
+         off_type real_size = m_vect.size();
          //Then maximize size for high watermarking
          m_vect.resize(m_vect.capacity());
          BOOST_ASSERT(m_vect.size() == m_vect.capacity());
@@ -208,11 +209,21 @@ class basic_vectorbuf
                this->setg(p, p, p + real_size);
          }
          if (m_mode & (std::ios_base::app | std::ios_base::ate)){
-            base_t::pbump((int)real_size);
+            this->pbump(real_size);
          }
       }
    }
 
+   // LWG255-inspired variant of base_t::pbump that takes a streamoff instead of an int.
+   void pbump(off_type delta) {
+      if (delta > INT_MAX) {
+            for (off_type d = delta / INT_MAX; d > 0; d--)
+                base_t::pbump(INT_MAX);
+            delta %= INT_MAX;
+      }
+      base_t::pbump((int)delta);
+   }
+
    protected:
    virtual int_type underflow() BOOST_OVERRIDE
    {
@@ -277,7 +288,7 @@ class basic_vectorbuf
                if (m_mode & std::ios_base::in)
                   base_t::setg(p, p + (base_t::gptr() - base_t::eback()), mp_high_water);
                //Update write position to the old position + 1
-               base_t::pbump((int)new_outpos);
+               this->pbump((off_type)new_outpos);
                return c;
          }
          else  // c is EOF, so we don't have to do anything
@@ -351,7 +362,7 @@ class basic_vectorbuf
          base_t::setg(base_t::eback(), base_t::eback() + newoff, base_t::egptr());
       if (out){
          base_t::setp(base_t::pbase(), base_t::epptr());
-         base_t::pbump(static_cast<int>(newoff));
+         this->pbump(newoff);
       }
       return pos_type(newoff);
    }