1 files changed, 55 insertions, 0 deletions
diff --git a/Source/kwsys/FStream.cxx b/Source/kwsys/FStream.cxx
new file mode 100644
index 0000000..5e4133a
--- /dev/null
+++ b/Source/kwsys/FStream.cxx
@@ -0,0 +1,55 @@
+/* Distributed under the OSI-approved BSD 3-Clause License.  See accompanying
+   file Copyright.txt or https://cmake.org/licensing#kwsys for details.  */
+#include "kwsysPrivate.h"
+#include KWSYS_HEADER(FStream.hxx)
+
+// Work-around CMake dependency scanning limitation.  This must
+// duplicate the above list of headers.
+#if 0
+#  include "FStream.hxx.in"
+#endif
+
+namespace KWSYS_NAMESPACE {
+namespace FStream {
+
+BOM ReadBOM(std::istream& in)
+{
+  if (!in.good()) {
+    return BOM_None;
+  }
+  unsigned long orig = in.tellg();
+  unsigned char bom[4];
+  in.read(reinterpret_cast<char*>(bom), 2);
+  if (!in.good()) {
+    in.clear();
+    in.seekg(orig);
+    return BOM_None;
+  }
+  if (bom[0] == 0xEF && bom[1] == 0xBB) {
+    in.read(reinterpret_cast<char*>(bom + 2), 1);
+    if (in.good() && bom[2] == 0xBF) {
+      return BOM_UTF8;
+    }
+  } else if (bom[0] == 0xFE && bom[1] == 0xFF) {
+    return BOM_UTF16BE;
+  } else if (bom[0] == 0x00 && bom[1] == 0x00) {
+    in.read(reinterpret_cast<char*>(bom + 2), 2);
+    if (in.good() && bom[2] == 0xFE && bom[3] == 0xFF) {
+      return BOM_UTF32BE;
+    }
+  } else if (bom[0] == 0xFF && bom[1] == 0xFE) {
+    unsigned long p = in.tellg();
+    in.read(reinterpret_cast<char*>(bom + 2), 2);
+    if (in.good() && bom[2] == 0x00 && bom[3] == 0x00) {
+      return BOM_UTF32LE;
+    }
+    in.seekg(p);
+    return BOM_UTF16LE;
+  }
+  in.clear();
+  in.seekg(orig);
+  return BOM_None;
+}
+
+} // FStream namespace
+} // KWSYS_NAMESPACE