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/* 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
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