Rename libs/integer to libs/endian

git-svn-id: http://svn.boost.org/svn/boost/sandbox/endian@72096 b8fc166d-592f-0410-95f2-cb63ce0dd405

libs/endian/example/endian_example.cpp

@@ -0,0 +1,74 @@
+// endian_example.cpp  -------------------------------------------------------//
+
+//  Copyright Beman Dawes, 2006
+
+//  Distributed under the Boost Software License, Version 1.0.
+//  See http://www.boost.org/LICENSE_1_0.txt
+
+//  See library home page at http://www.boost.org/libs/endian
+
+//----------------------------------------------------------------------------//
+
+#define _CRT_SECURE_NO_DEPRECATE  // quiet VC++ 8.0 foolishness
+
+#include <iostream>
+#include <cassert>
+#include <cstdio>
+#include <boost/integer/endian.hpp>
+
+using namespace boost::integer;
+
+namespace 
+{
+  //  This is an extract from a very widely used GIS file format. I have no idea
+  //  why a designer would mix big and little endians in the same file - but
+  //  this is a real-world format and users wishing to write low level code
+  //  manipulating these files have to deal with the mixed endianness.
+
+  struct header
+  {
+    big32_t     file_code;
+    big32_t     file_length;
+    little32_t  version;
+    little32_t  shape_type;
+  };
+
+  const char * filename = "test.dat";
+}
+
+int main()
+{
+  assert( sizeof( header ) == 16 );  // requirement for interoperability
+  
+  header h;
+
+  h.file_code   = 0x04030201;
+  h.file_length = sizeof( header );
+  h.version     = -1;
+  h.shape_type  = 0x04030201;
+
+  //  Low-level I/O such as POSIX read/write or <cstdio> fread/fwrite is sometimes
+  //  used for binary file operations when ultimate efficiency is important.
+  //  Such I/O is often performed in some C++ wrapper class, but to drive home the
+  //  point that endian integers are often used in fairly low-level code that
+  //  does bulk I/O operations, <cstdio> fopen/fwrite is used for I/O in this example.
+
+  std::FILE * fi;
+  
+  if ( !(fi = std::fopen( filename, "wb" )) )  // MUST BE BINARY
+  {
+    std::cout << "could not open " << filename << '\n';
+    return 1;
+  }
+
+  if ( std::fwrite( &h, sizeof( header ), 1, fi ) != 1 ) 
+  {
+    std::cout << "write failure for " << filename << '\n';
+    return 1;
+  }
+
+  std::fclose( fi );
+
+  std::cout << "created file " << filename << '\n';
+  return 0;
+}