Add ReaderStreamBuf and WriterStreamBuf for std::istream and std::ostream interfaces.

1 files changed, 40 insertions, 0 deletions

diff --git a/coding/reader_streambuf.cpp b/coding/reader_streambuf.cpp
new file mode 100644
index 0000000000..3cfaef1fc8
--- /dev/null
+++ b/coding/reader_streambuf.cpp
@@ -0,0 +1,40 @@
+#include "reader_streambuf.hpp"
+#include "reader.hpp"
+
+#include "../std/algorithm.hpp"
+
+
+ReaderStreamBuf::ReaderStreamBuf(Reader * p)
+: m_p(p), m_pos(0), m_size(p->Size())
+{
+}
+
+ReaderStreamBuf::~ReaderStreamBuf()
+{
+  delete m_p;
+}
+
+std::streamsize ReaderStreamBuf::xsgetn(char_type * s, std::streamsize n)
+{
+  uint64_t const count = min(static_cast<uint64_t>(n), m_size - m_pos);
+  if (count > 0)
+  {
+    m_p->Read(m_pos, s, count);
+    m_pos += count;
+  }
+  return count;
+}
+
+ReaderStreamBuf::int_type ReaderStreamBuf::underflow()
+{
+  std::streamsize s = xsgetn(m_buf, sizeof(m_buf));
+  if (s > 0)
+  {
+    setg(m_buf, m_buf, m_buf + s);
+    return traits_type::to_int_type(m_buf[0]);
+  }
+  else
+  {
+    return traits_type::eof();
+  }
+}