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#include "PrebufferedStreambuf.h"
PrebufferedStreambuf::PrebufferedStreambuf(char *buf, size_t len)
: m_buf(buf), m_buf_len(len)
{
// init output buffer
this->setp(m_buf, m_buf + m_buf_len);
// so we underflow on first read
this->setg(0, 0, 0);
}
PrebufferedStreambuf::int_type PrebufferedStreambuf::overflow(int_type c)
{
int old_len = m_overflow.size();
if (old_len == 0) {
m_overflow.resize(m_buf_len);
} else {
m_overflow.resize(old_len * 2);
}
m_overflow[old_len] = c;
this->setp(&m_overflow[old_len + 1], &*m_overflow.begin() + m_overflow.size());
return std::char_traits<char>::not_eof(c);
}
PrebufferedStreambuf::int_type PrebufferedStreambuf::underflow()
{
if (this->gptr() == 0) {
// first read; start with the static buffer
if (m_overflow.size())
// there is overflow, so start with entire prealloc buffer
this->setg(m_buf, m_buf, m_buf + m_buf_len);
else if (this->pptr() == m_buf)
// m_buf is empty
return traits_ty::eof(); // no data
else
// set up portion of m_buf we've filled
this->setg(m_buf, m_buf, this->pptr());
return *this->gptr();
}
if (this->gptr() == m_buf + m_buf_len && m_overflow.size()) {
// at end of m_buf; continue with the overflow string
this->setg(&m_overflow[0], &m_overflow[0], this->pptr());
return *this->gptr();
}
// otherwise we must be at the end (of m_buf and/or m_overflow)
return traits_ty::eof();
}
std::string PrebufferedStreambuf::get_str() const
{
if (m_overflow.size()) {
std::string s(m_buf, m_buf + m_buf_len);
s.append(&m_overflow[0], this->pptr() - &m_overflow[0]);
return s;
} else if (this->pptr() == m_buf) {
return std::string();
} else {
return std::string(m_buf, this->pptr() - m_buf);
}
}
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