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// file : libbutl/char-scanner.cxx -*- C++ -*-
// copyright : Copyright (c) 2014-2017 Code Synthesis Ltd
// license : MIT; see accompanying LICENSE file
#include <libbutl/char-scanner.hxx>
using namespace std;
namespace butl
{
char_scanner::
char_scanner (istream& is, bool crlf)
: is_ (is),
buf_ (dynamic_cast<fdbuf*> (is.rdbuf ())),
gptr_ (nullptr),
egptr_ (nullptr),
crlf_ (crlf)
{
}
auto char_scanner::
peek () -> xchar
{
if (unget_)
return ungetc_;
if (unpeek_)
return unpeekc_;
if (eos_)
return xchar (xchar::traits_type::eof (), line, column);
int_type v (peek_ ());
if (v == xchar::traits_type::eof ())
eos_ = true;
else if (crlf_ && v == '\r')
{
get_ ();
int_type v1 (peek_ ());
if (v1 != '\n')
{
// We need to make sure subsequent calls to peek() return newline.
//
unpeek_ = true;
unpeekc_ = xchar ('\n', line, column);
}
v = '\n';
}
return xchar (v, line, column);
}
void char_scanner::
get (const xchar& c)
{
if (unget_)
unget_ = false;
else if (unpeek_)
unpeek_ = false;
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).
//
if (!eos (c))
{
get_ ();
if (c == '\n')
{
line++;
column = 1;
}
else
column++;
}
}
}
}
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