Add tmpfile() implementation of FILE_Cookie.

6 files changed, 154 insertions, 10 deletions

diff --git a/configure.ac b/configure.ac
index 03014f8..ad52306 100644
--- a/configure.ac
+++ b/configure.ac
@@ -29,6 +29,8 @@ AC_PROG_LN_S
 AC_PROG_MAKE_SET
 AC_PROG_LIBTOOL
 
+AM_CONDITIONAL([FOPENCOOKIE], false)
+
 dnl Generate Makefiles
 AC_CONFIG_MACRO_DIR([m4])
 AC_CONFIG_FILES([Makefile
diff --git a/libdimensionxx/Makefile.am b/libdimensionxx/Makefile.am
index 143ab83..74eb03b 100644
--- a/libdimensionxx/Makefile.am
+++ b/libdimensionxx/Makefile.am
@@ -23,6 +23,13 @@ INCLUDES = -I../libdimension -I../libdimension-png
 
 lib_LTLIBRARIES = libdimensionxx.la
 
-libdimensionxx_la_SOURCES = $(nobase_include_HEADERS) canvas.cpp color.cpp cookie.cpp error.cpp png.cpp
+libdimensionxx_la_SOURCES = $(nobase_include_HEADERS) canvas.cpp color.cpp error.cpp png.cpp
+
+if FOPENCOOKIE
+  libdimensionxx_la_SOURCES += cookie-fopencookie.cpp
+else
+  libdimensionxx_la_SOURCES += cookie-tmpfile.cpp
+endif
+
 libdimensionxx_la_LDFLAGS = -version-info 0:0:0
 libdimensionxx_la_LIBADD  = ../libdimension/libdimension.la ../libdimension-png/libdimension-png.la
diff --git a/libdimensionxx/cookie.cpp b/libdimensionxx/cookie-fopencookie.cpp
index 962137a..9fd4e07 100644
--- a/libdimensionxx/cookie.cpp
+++ b/libdimensionxx/cookie-fopencookie.cpp
@@ -22,11 +22,11 @@
 #include <stdio.h>
 
 // The conundrum: libdimension and libdimension-* use C I/O, with FILE*'s.
-// We want to use C++ I/O with std::i/ostreams.  Unfortunately, there's no
-// standard way to map between them, so we use the nonportable GNU stdio
-// extension fopencookie(), which creates a FILE* with custom read/write/seek
-// functions.  BSD also has a similar function, funopen(), which we should
-// use too.  Failing in all that, we should fall back on a tmpfile() buffer.
+// We want to use C++ I/O with std::i/ostreams. If present, we use the
+// nonportable GNU stdio extension fopencookie(), which creates a FILE* with
+// custom read/write/seek functions.  BSD also has a similar function, funopen()
+// which we should use too.  Failing in all that, fall back on a tmpfile()
+// buffer (see cookie-tmpfile.cpp).
 
 namespace Dimension
 {
diff --git a/libdimensionxx/cookie-tmpfile.cpp b/libdimensionxx/cookie-tmpfile.cpp
new file mode 100644
index 0000000..ec320d8
--- /dev/null
+++ b/libdimensionxx/cookie-tmpfile.cpp
@@ -0,0 +1,136 @@
+/*************************************************************************
+ * Copyright (C) 2008 Tavian Barnes <tavianator@gmail.com>               *
+ *                                                                       *
+ * This file is part of The Dimension Library.                           *
+ *                                                                       *
+ * The Dimension Library is free software; you can redistribute it and/  *
+ * or modify it under the terms of the GNU Lesser General Public License *
+ * as published by the Free Software Foundation; either version 3 of the *
+ * License, or (at your option) any later version.                       *
+ *                                                                       *
+ * The Dimension Library is distributed in the hope that it will be      *
+ * useful, but WITHOUT ANY WARRANTY; without even the implied warranty   *
+ * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU  *
+ * Lesser General Public License for more details.                       *
+ *                                                                       *
+ * You should have received a copy of the GNU Lesser General Public      *
+ * License along with this program.  If not, see                         *
+ * <http://www.gnu.org/licenses/>.                                       *
+ *************************************************************************/
+
+#include "dimensionxx.hpp"
+#include <stdio.h>
+
+// Use a tmpfile as a buffer for a C++/C I/O interface.
+
+namespace Dimension
+{
+  namespace
+  {
+    void
+    write_cookie(FILE* file, std::istream& istr)
+    {
+      unsigned int count, pos;
+      const unsigned int bs = 8192;
+      char buffer[bs];
+
+      pos = istr.tellg();
+      istr.seekg(0);
+      while (true) {
+        istr.read(buffer, bs);
+        count = istr.gcount();
+
+        if (count != bs) {
+          if (istr.eof()) {
+            fwrite(buffer, 1, count, file);
+            break;
+          } else {
+            throw Dimension_Error("Error reading from input stream.");
+          }
+        }
+
+        fwrite(buffer, 1, bs, file);
+      }
+      fseek(file, pos, SEEK_SET);
+    }
+
+    void
+    read_cookie(std::ostream& ostr, FILE* file)
+    {
+      unsigned int count, pos;
+      const unsigned int bs = 8192;
+      char buffer[bs];
+
+      pos = ftell(file);
+      rewind(file);
+      while (true) {
+        count = fread(buffer, 1, bs, file);
+        if (count != bs) {
+          if (feof(file)) {
+            ostr.write(buffer, count);
+            break;
+          } else {
+            throw Dimension_Error("Error reading from temporary file.");
+          }
+        }
+
+        ostr.write(buffer, bs);
+      }
+      ostr.seekp(pos);
+    }
+  }
+
+  // Make an input FILE_Cookie
+  FILE_Cookie::FILE_Cookie(std::istream& istr)
+    : m_file(tmpfile()), m_istr(&istr), m_ostr(0)
+  {
+    if (!m_file) {
+      throw Dimension_Error("Error opening temporary file for C++/C I/O"
+                            " interface.");
+    }
+
+    write_cookie(m_file, *m_istr);
+  }
+
+  // Make an output FILE_Cookie
+  FILE_Cookie::FILE_Cookie(std::ostream& ostr)
+    : m_file(tmpfile()), m_istr(0), m_ostr(&ostr)
+  {
+    if (!m_file) {
+      throw Dimension_Error("Error opening temporary file for C++/C I/O"
+                            " interface.");
+    }
+  }
+
+  // Make an I/O FILE_Cookie
+  FILE_Cookie::FILE_Cookie(std::iostream& iostr)
+    : m_file(tmpfile()), m_istr(&iostr), m_ostr(&iostr)
+  {
+    if (!m_file) {
+      throw Dimension_Error("Error opening temporary file for C++/C I/O"
+                            " interface.");
+    }
+
+    write_cookie(m_file, *m_istr);
+  }
+
+  // Close the tmpfile, maybe syncing a C++ stream to it first
+  FILE_Cookie::~FILE_Cookie() {
+    if (is_output()) {
+      read_cookie(*m_ostr, m_file);
+    }
+
+    std::fclose(m_file);
+  }
+
+  FILE*       FILE_Cookie::file()       { return m_file; }
+  const FILE* FILE_Cookie::file() const { return m_file; }
+
+  bool FILE_Cookie::is_input()  const { return m_istr; }
+  bool FILE_Cookie::is_output() const { return m_ostr; }
+
+  std::istream&       FILE_Cookie::istr()       { return *m_istr; }
+  const std::istream& FILE_Cookie::istr() const { return *m_istr; }
+  std::ostream&       FILE_Cookie::ostr()       { return *m_ostr; }
+  const std::ostream& FILE_Cookie::ostr() const { return *m_ostr; }
+}
diff --git a/libdimensionxx/dimensionxx/cookie.hpp b/libdimensionxx/dimensionxx/cookie.hpp
index a2a3324..df26b93 100644
--- a/libdimensionxx/dimensionxx/cookie.hpp
+++ b/libdimensionxx/dimensionxx/cookie.hpp
@@ -21,8 +21,7 @@
 #ifndef DIMENSIONXX_COOKIE_HPP
 #define DIMENSIONXX_COOKIE_HPP
 
-// Some internal magic to use C FILE* I/O with C++ streams.  Currently this ties
-// us to Linux and glibc, but in the future, this will be portable.
+// Some internal magic to use C FILE* I/O with C++ streams.
 
 #include <istream>
 #include <ostream>
@@ -36,7 +35,7 @@ namespace Dimension
   public:
     FILE_Cookie(std::istream& istr);
     FILE_Cookie(std::ostream& ostr);
-    FILE_Cookie(std::istream& istr, std::ostream& ostr);
+    FILE_Cookie(std::iostream& iostr);
     ~FILE_Cookie();
 
     FILE*       file();
diff --git a/libdimensionxx/png.cpp b/libdimensionxx/png.cpp
index 8a2770b..2d1d276 100644
--- a/libdimensionxx/png.cpp
+++ b/libdimensionxx/png.cpp
@@ -67,7 +67,7 @@ namespace Dimension
     m_written = true; // We've written the file now, don't do it again
   }
 
-  // Read a canvas from a  PNG file.  Uses the FILE_Cookie() interface to make a
+  // Read a canvas from a PNG file.  Uses the FILE_Cookie() interface to make a
   // FILE* corresponding to an std::istream (including std::istringstream, etc).
   void PNG_Canvas::read()
   {