1 files changed, 37 insertions, 0 deletions
diff --git a/src/rbd_replay/BufferReader.cc b/src/rbd_replay/BufferReader.cc
new file mode 100644
index 000000000..b4dce6515
--- /dev/null
+++ b/src/rbd_replay/BufferReader.cc
@@ -0,0 +1,37 @@
+// -*- 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/ceph_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) {
+  ceph_assert(m_min_bytes <= m_max_bytes);
+}
+
+int BufferReader::fetch(bufferlist::const_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;
+      }
+      ceph_assert(r <= bytes_to_read);
+      bytes_to_read -= r;
+    }
+  }
+
+  *it = &m_bl_it;
+  return 0;
+}
+
+} // namespace rbd_replay