1 files changed, 44 insertions, 0 deletions
diff --git a/llvm/lib/Support/circular_raw_ostream.cpp b/llvm/lib/Support/circular_raw_ostream.cpp
new file mode 100644
index 000000000000..acd230704ff8
--- /dev/null
+++ b/llvm/lib/Support/circular_raw_ostream.cpp
@@ -0,0 +1,44 @@
+//===- circular_raw_ostream.cpp - Implement circular_raw_ostream ----------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+//
+// This implements support for circular buffered streams.
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm/Support/circular_raw_ostream.h"
+#include <algorithm>
+using namespace llvm;
+
+void circular_raw_ostream::write_impl(const char *Ptr, size_t Size) {
+  if (BufferSize == 0) {
+    TheStream->write(Ptr, Size);
+    return;
+  }
+
+  // Write into the buffer, wrapping if necessary.
+  while (Size != 0) {
+    unsigned Bytes =
+      std::min(unsigned(Size), unsigned(BufferSize - (Cur - BufferArray)));
+    memcpy(Cur, Ptr, Bytes);
+    Size -= Bytes;
+    Cur += Bytes;
+    if (Cur == BufferArray + BufferSize) {
+      // Reset the output pointer to the start of the buffer.
+      Cur = BufferArray;
+      Filled = true;
+    }
+  }
+}
+
+void circular_raw_ostream::flushBufferWithBanner() {
+  if (BufferSize != 0) {
+    // Write out the buffer
+    TheStream->write(Banner, std::strlen(Banner));
+    flushBuffer();
+  }
+}