1 files changed, 54 insertions, 0 deletions
diff --git a/vespalib/src/vespa/vespalib/data/lz4_output_encoder.cpp b/vespalib/src/vespa/vespalib/data/lz4_output_encoder.cpp
new file mode 100644
index 00000000000..60f8546bde1
--- /dev/null
+++ b/vespalib/src/vespa/vespalib/data/lz4_output_encoder.cpp
@@ -0,0 +1,54 @@
+// Copyright 2017 Yahoo Inc. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
+
+#include <vespa/fastos/fastos.h>
+#include "lz4_output_encoder.h"
+#include <lz4frame.h>
+
+namespace vespalib {
+
+void
+Lz4OutputEncoder::encode_frame()
+{
+    auto dst = _output.reserve(LZ4F_compressFrameBound(_used, nullptr));
+    size_t written = LZ4F_compressFrame(dst.data, dst.size, &_buffer[0], _used, nullptr);
+    assert(!LZ4F_isError(written));
+    assert(written <= dst.size);
+    _output.commit(written);
+    _used = 0;
+}
+
+Lz4OutputEncoder::Lz4OutputEncoder(Output &output, size_t buffer_size)
+    : _output(output),
+      _buffer(buffer_size, 0),
+      _used(0),
+      _limit(buffer_size)
+{
+}
+
+Lz4OutputEncoder::~Lz4OutputEncoder()
+{
+    if (_used > 0) {
+        encode_frame();
+    }
+}
+
+WritableMemory
+Lz4OutputEncoder::reserve(size_t bytes)
+{
+    if ((_used + bytes) > _buffer.size()) {
+        _buffer.resize(_used + bytes, 0);
+    }
+    return WritableMemory(&_buffer[_used], (_buffer.size() - _used));
+}
+
+Output &
+Lz4OutputEncoder::commit(size_t bytes)
+{
+    _used += bytes;
+    if (_used >= _limit) {
+        encode_frame();
+    }
+    return *this;
+}
+
+} // namespace vespalib