53 lines
1.9 KiB
C++
53 lines
1.9 KiB
C++
//===- DeltaTree.h - B-Tree for Rewrite Delta tracking ----------*- C++ -*-===//
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//
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// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
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// See https://llvm.org/LICENSE.txt for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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//
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//===----------------------------------------------------------------------===//
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//
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// This file defines the DeltaTree class.
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//
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//===----------------------------------------------------------------------===//
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#ifndef LLVM_ADT_DELTATREE_H
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#define LLVM_ADT_DELTATREE_H
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#include "llvm/Support/Compiler.h"
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namespace llvm {
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/// A multiway search tree (BTree) structure with some fancy
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/// features. B-Trees are generally more memory and cache efficient than
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/// binary trees, because they store multiple keys/values in each node. This
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/// implements a key/value mapping from index to delta, and allows fast lookup
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/// on index. However, an added (important) bonus is that it can also
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/// efficiently tell us the full accumulated delta for a specific file offset
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/// as well, without traversing the whole tree.
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class DeltaTree {
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void *Root; // "DeltaTreeNode *"
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public:
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LLVM_ABI DeltaTree();
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// Note: Currently we only support copying when the RHS is empty.
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LLVM_ABI DeltaTree(const DeltaTree &RHS);
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DeltaTree &operator=(const DeltaTree &) = delete;
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LLVM_ABI ~DeltaTree();
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/// Return the accumulated delta at the specified file offset.
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/// This includes all insertions or delections that occurred *before* the
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/// specified file index.
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LLVM_ABI int getDeltaAt(unsigned FileIndex) const;
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/// When a change is made that shifts around the text buffer,
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/// this method is used to record that info. It inserts a delta of 'Delta'
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/// into the current DeltaTree at offset FileIndex.
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LLVM_ABI void AddDelta(unsigned FileIndex, int Delta);
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};
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} // namespace llvm
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#endif // LLVM_ADT_DELTATREE_H
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