--- /dev/null
+// -*- mode:C++; tab-width:8; c-basic-offset:2; indent-tabs-mode:t -*-
+// vim: ts=8 sw=2 smarttab
+
+#include "rbd_replay/BufferReader.h"
+#include "include/assert.h"
+#include "include/intarith.h"
+
+namespace rbd_replay {
+
+BufferReader::BufferReader(int fd, size_t min_bytes, size_t max_bytes)
+ : m_fd(fd), m_min_bytes(min_bytes), m_max_bytes(max_bytes),
+ m_bl_it(m_bl.begin()), m_eof_reached(false) {
+ assert(m_min_bytes <= m_max_bytes);
+}
+
+int BufferReader::fetch(bufferlist::iterator **it) {
+ if (m_bl_it.get_remaining() < m_min_bytes) {
+ ssize_t bytes_to_read = ROUND_UP_TO(m_max_bytes - m_bl_it.get_remaining(),
+ CEPH_PAGE_SIZE);
+ while (!m_eof_reached && bytes_to_read > 0) {
+ int r = m_bl.read_fd(m_fd, CEPH_PAGE_SIZE);
+ if (r < 0) {
+ return r;
+ }
+ if (r == 0) {
+ m_eof_reached = true;
+ }
+ assert(r <= bytes_to_read);
+ bytes_to_read -= r;
+ }
+ }
+
+ *it = &m_bl_it;
+ return 0;
+}
+
+} // namespace rbd_replay