bool transferLeft(cyclic_buffer<capacity>& buf, In& in, Out& out) {
if (!buf.isEmpty()) {
transfer(buf, out);
} else {
try {
// read() throws exception if nothing can be read
transfer(in, buf);
// Or doesn't throw returning 0?
return buf.isEmpty();
} catch (const errno_exception& ex) {
return true;
}
}
}
void transfer(cyclic_buffer<capacity>& buf, Out& out) {
if (!buf.isEmpty()) {
char buffer[TRANSFER_CHUNK_SIZE];
size_t s = buf.seek(buffer, sizeof(buffer));
size_t numWritten = out.write(buffer, s);
buf.skip(numWritten);
}
}