/// read portion of file into internal buffer
/// if a_crunch == true, crunch buffer before reading
bool read(bool a_crunch = true) {
if (!m_open || !m_file.is_open())
return false;
if (a_crunch)
m_buf.crunch();
while (true) {
BOOST_ASSERT(m_buf.capacity() > 0);
m_file.read(m_buf.wr_ptr(), m_buf.capacity());
int n = m_file.gcount();
if (n == 0) {
if (m_file.good()) continue;
if (m_file.eof()) return false;
// this should never happen since we have set badbit
throw io_error(errno, "Unexpected error reading ", m_fname);
}
m_buf.commit(n);
return true;
}
}
char* wr_ptr() { return m_buf.wr_ptr(); }