static CharT decode_octal (state &state_)
{
std::size_t accumulator_ = 0;
CharT ch_ = *state_._curr;
unsigned short count_ = 3;
bool eos_ = false;
for (;;)
{
accumulator_ *= 8;
accumulator_ += ch_ - '0';
--count_;
state_.increment ();
eos_ = state_.eos ();
if (!count_ || eos_) break;
ch_ = *state_._curr;
// Don't consume invalid chars!
if (ch_ < '0' || ch_ > '7')
{
break;
}
}
return static_cast<CharT> (accumulator_);
}
static CharT decode_control_char (state &state_)
{
// Skip over 'c'
state_.increment ();
CharT ch_ = 0;
bool eos_ = state_.next (ch_);
if (eos_)
{
// Pointless returning index if at end of string
throw runtime_error ("Unexpected end of regex following \\c.");
}
else
{
if (ch_ >= 'a' && ch_ <= 'z')
{
ch_ -= 'a' - 1;
}
else if (ch_ >= 'A' && ch_ <= 'Z')
{
ch_ -= 'A' - 1;
}
else if (ch_ == '@')
{
// Apparently...
ch_ = 0;
}
else
{
std::ostringstream ss_;
ss_ << "Invalid control char at index " <<
state_.index () - 1 << '.';
throw runtime_error (ss_.str ().c_str ());
}
}
return ch_;
}
static CharT decode_hex (state &state_)
{
// Skip over 'x'
state_.increment ();
CharT ch_ = 0;
bool eos_ = state_.next (ch_);
if (eos_)
{
// Pointless returning index if at end of string
throw runtime_error ("Unexpected end of regex following \\x.");
}
if (!((ch_ >= '0' && ch_ <= '9') || (ch_ >= 'a' && ch_ <= 'f') ||
(ch_ >= 'A' && ch_ <= 'F')))
{
std::ostringstream ss_;
ss_ << "Illegal char following \\x at index " <<
state_.index () - 1 << '.';
throw runtime_error (ss_.str ().c_str ());
}
std::size_t hex_ = 0;
do
{
hex_ *= 16;
if (ch_ >= '0' && ch_ <= '9')
{
hex_ += ch_ - '0';
}
else if (ch_ >= 'a' && ch_ <= 'f')
{
hex_ += 10 + (ch_ - 'a');
}
else
{
hex_ += 10 + (ch_ - 'A');
}
eos_ = state_.eos ();
if (!eos_)
{
ch_ = *state_._curr;
// Don't consume invalid chars!
if (((ch_ >= '0' && ch_ <= '9') ||
(ch_ >= 'a' && ch_ <= 'f') || (ch_ >= 'A' && ch_ <= 'F')))
{
state_.increment ();
}
else
{
eos_ = true;
}
}
} while (!eos_);
return static_cast<CharT> (hex_);
}
static CharT chr (state &state_)
{
CharT ch_ = 0;
// eos_ has already been checked for.
switch (*state_._curr)
{
case '0':
case '1':
case '2':
case '3':
case '4':
case '5':
case '6':
case '7':
ch_ = decode_octal (state_);
break;
case 'a':
ch_ = '\a';
state_.increment ();
break;
case 'b':
ch_ = '\b';
state_.increment ();
break;
case 'c':
ch_ = decode_control_char (state_);
break;
case 'e':
ch_ = 27; // '\e' not recognised by compiler
state_.increment ();
break;
case 'f':
ch_ = '\f';
state_.increment ();
break;
case 'n':
ch_ = '\n';
state_.increment ();
break;
case 'r':
ch_ = '\r';
state_.increment ();
break;
case 't':
ch_ = '\t';
state_.increment ();
break;
case 'v':
ch_ = '\v';
state_.increment ();
break;
case 'x':
ch_ = decode_hex (state_);
break;
default:
ch_ = *state_._curr;
state_.increment ();
break;
}
return ch_;
}
