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// file : butl/char-scanner.cxx -*- C++ -*-
// copyright : Copyright (c) 2014-2017 Code Synthesis Ltd
// license : MIT; see accompanying LICENSE file
#include <butl/char-scanner>
#include <istream>
using namespace std;
namespace butl
{
auto char_scanner::
peek () -> xchar
{
if (unget_)
return buf_;
else
{
if (eos_)
return xchar (xchar::traits_type::eof (), line, column);
else
{
xchar::int_type v (is_.peek ());
if (v == xchar::traits_type::eof ())
eos_ = true;
return xchar (v, line, column);
}
}
}
auto char_scanner::
get () -> xchar
{
if (unget_)
{
unget_ = false;
return buf_;
}
else
{
// When is_.get () returns eof, the failbit is also set (stupid,
// isn't?) which may trigger an exception. To work around this
// we will call peek() first and only call get() if it is not
// eof. But we can only call peek() on eof once; any subsequent
// calls will spoil the failbit (even more stupid).
//
xchar c (peek ());
if (!eos (c))
{
is_.get ();
if (crlf_ && c == 0x0D)
{
xchar c1 (peek ());
if (c1 == '\n')
{
is_.get ();
c = c1;
}
}
if (c == '\n')
{
line++;
column = 1;
}
else
column++;
}
return c;
}
}
void char_scanner::
unget (const xchar& c)
{
// Because iostream::unget cannot work once eos is reached,
// we have to provide our own implementation.
//
buf_ = c;
unget_ = true;
}
}
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