Visual C++ and mingw32 fixes for large files

config-mingw32

@@ -1,2 +1,13 @@
 #!/bin/sh
 ./configure --disable-test-compare-images --enable-external-libs --with-windows-wordsize=32 --with-buildrules=mingw
+# As of autoconf 2.69 and gcc 4.6, autoconf's configure fails to
+# recognize that defining _FILE_OFFSET_BITS works with mingw32.
+# Append to qpdf-config.h rather than passing CPPFLAGS on the
+# commandline.  This way we don't defeat the fact that test_large_file
+# and other things that only use the public interface can be built
+# without any special flags.
+cat >> libqpdf/qpdf/qpdf-config.h <<EOF
+#ifndef _FILE_OFFSET_BITS
+# define _FILE_OFFSET_BITS 64
+#endif
+EOF

configure.ac

@@ -64,6 +64,7 @@ AC_ARG_WITH(large-file-test-path,
 
 AC_SYS_LARGEFILE
 AC_FUNC_FSEEKO
+AC_CHECK_FUNCS([fseeko64])
 AC_TYPE_UINT16_T
 AC_TYPE_UINT32_T
 

libqpdf/QUtil.cc

@@ -126,8 +126,14 @@ QUtil::fseek_off_t(FILE* stream, qpdf_offset_t offset, int whence)
 {
 #if HAVE_FSEEKO
     return fseeko(stream, (off_t)offset, whence);
+#elif HAVE_FSEEKO64
+    return fseeko64(stream, offset, whence);
 #else
+# ifdef _MSC_VER
+    return _fseeki64(stream, offset, whence);
+# else
     return fseek(stream, (long)offset, whence);
+# endif
 #endif
 }
 
@@ -136,8 +142,14 @@ QUtil::ftell_off_t(FILE* stream)
 {
 #if HAVE_FSEEKO
     return (qpdf_offset_t)ftello(stream);
+#elif HAVE_FSEEKO64
+    return (qpdf_offset_t)ftello64(stream);
 #else
+# ifdef _MSC_VER
+    return _ftelli64(stream);
+# else
     return (qpdf_offset_t)ftell(stream);
+# endif
 #endif
 }