Index: tools/relocation_packer/src/sleb128.h |
diff --git a/tools/relocation_packer/src/sleb128.h b/tools/relocation_packer/src/sleb128.h |
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index 0000000000000000000000000000000000000000..3544543c0d6f6d6bf2ff5f6ec0acddd253f3de29 |
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+// Copyright 2014 The Chromium Authors. All rights reserved. |
+// Use of this source code is governed by a BSD-style license that can be |
+// found in the LICENSE file. |
+ |
+// SLEB128 encoder and decoder for packed relative relocations. |
+// |
+// Delta encoded relative relocations consist of a large number |
+// of pairs signed integer values, many with small values. Encoding these |
+// as signed LEB128 saves space. |
+// |
+// For more on LEB128 see http://en.wikipedia.org/wiki/LEB128. |
+ |
+#ifndef TOOLS_RELOCATION_PACKER_SRC_SLEB128_H_ |
+#define TOOLS_RELOCATION_PACKER_SRC_SLEB128_H_ |
+ |
+#include <stdint.h> |
+#include <unistd.h> |
+#include <vector> |
+ |
+#include "elf_traits.h" |
+ |
+namespace relocation_packer { |
+ |
+// Encode packed words as a signed LEB128 byte stream. |
+class Sleb128Encoder { |
+ public: |
+ // Explicit (but empty) constructor and destructor, for chromium-style. |
+ Sleb128Encoder(); |
+ ~Sleb128Encoder(); |
+ |
+ // Add a value to the encoding stream. |
+ // |value| is the signed int to add. |
+ void Enqueue(ELF::Sxword value); |
+ |
+ // Add a vector of values to the encoding stream. |
+ // |values| is the vector of signed ints to add. |
+ void EnqueueAll(const std::vector<ELF::Sxword>& values); |
+ |
+ // Retrieve the encoded representation of the values. |
+ // |encoding| is the returned vector of encoded data. |
+ void GetEncoding(std::vector<uint8_t>* encoding) { *encoding = encoding_; } |
+ |
+ private: |
+ // Growable vector holding the encoded LEB128 stream. |
+ std::vector<uint8_t> encoding_; |
+}; |
+ |
+// Decode a LEB128 byte stream to produce packed words. |
+class Sleb128Decoder { |
+ public: |
+ // Create a new decoder for the given encoded stream. |
+ // |encoding| is the vector of encoded data. |
+ explicit Sleb128Decoder(const std::vector<uint8_t>& encoding); |
+ |
+ // Explicit (but empty) destructor, for chromium-style. |
+ ~Sleb128Decoder(); |
+ |
+ // Retrieve the next value from the encoded stream. |
+ ELF::Sxword Dequeue(); |
+ |
+ // Retrieve all remaining values from the encoded stream. |
+ // |values| is the vector of decoded data. |
+ void DequeueAll(std::vector<ELF::Sxword>* values); |
+ |
+ private: |
+ // Encoded LEB128 stream. |
+ std::vector<uint8_t> encoding_; |
+ |
+ // Cursor indicating the current stream retrieval point. |
+ size_t cursor_; |
+}; |
+ |
+} // namespace relocation_packer |
+ |
+#endif // TOOLS_RELOCATION_PACKER_SRC_SLEB128_H_ |