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// file : libbutl/char-scanner.cxx -*- C++ -*-
// copyright : Copyright (c) 2014-2019 Code Synthesis Ltd
// license : MIT; see accompanying LICENSE file
#ifndef __cpp_modules_ts
#include <libbutl/char-scanner.mxx>
#endif
// C includes.
#ifndef __cpp_lib_modules_ts
#include <string> // char_traits
#include <cstdint> // uint64_t
#include <istream>
#endif
// Other includes.
#ifdef __cpp_modules_ts
module butl.char_scanner;
// Only imports additional to interface.
#ifdef __clang__
#ifdef __cpp_lib_modules_ts
import std.core;
import std.io;
#endif
import butl.fdstream;
#endif
#endif
using namespace std;
namespace butl
{
char_scanner::
char_scanner (istream& is, bool crlf, uint64_t l, uint64_t p)
: line (l),
column (1),
position (p),
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, position);
int_type v (peek_ ());
if (v == xchar::traits_type::eof ())
eos_ = true;
else if (crlf_ && v == '\r')
{
int_type v1;
do
{
get_ ();
v1 = peek_ ();
}
while (v1 == '\r');
if (v1 != '\n')
{
// We need to make sure subsequent calls to peek() return newline.
//
unpeek_ = true;
unpeekc_ = xchar ('\n', line, column, position);
if (v1 == xchar::traits_type::eof ())
eos_ = true;
}
v = '\n';
}
return xchar (v, line, column, position);
}
void char_scanner::
get (const xchar& c)
{
if (unget_)
unget_ = false;
else
{
if (unpeek_)
{
unpeek_ = false;
}
// 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).
//
else if (!eos (c))
get_ ();
if (!eos (c))
{
if (c == '\n')
{
line++;
column = 1;
}
else
column++;
position = pos_ ();
}
}
}
}
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