Uleb128 compression of vmap and mapping table.

Bug 9437697.

Change-Id: I30bcb97d12cd8b46d3b2cdcbdd358f08fbb9947a
(cherry picked from commit 1809a72a66d245ae598582d658b93a24ac3bf01e)

1 files changed, 63 insertions, 0 deletions

diff --git a/compiler/leb128_encoder.h b/compiler/leb128_encoder.h
new file mode 100644
index 0000000..e9a1c32
--- /dev/null
+++ b/compiler/leb128_encoder.h
@@ -0,0 +1,63 @@
+/*
+ * Copyright (C) 2011 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#ifndef ART_COMPILER_LEB128_ENCODER_H_
+#define ART_COMPILER_LEB128_ENCODER_H_
+
+#include "base/macros.h"
+
+namespace art {
+
+// An encoder with an API similar to vector<uint32_t> where the data is captured in ULEB128 format.
+class UnsignedLeb128EncodingVector {
+ public:
+  UnsignedLeb128EncodingVector() {
+  }
+
+  void PushBack(uint32_t value) {
+    bool done = false;
+    do {
+      uint8_t out = value & 0x7f;
+      if (out != value) {
+        data_.push_back(out | 0x80);
+        value >>= 7;
+      } else {
+        data_.push_back(out);
+        done = true;
+      }
+    } while (!done);
+  }
+
+  template<typename It>
+  void InsertBack(It cur, It end) {
+    for (; cur != end; ++cur) {
+      PushBack(*cur);
+    }
+  }
+
+  const std::vector<uint8_t>& GetData() const {
+    return data_;
+  }
+
+ private:
+  std::vector<uint8_t> data_;
+
+  DISALLOW_COPY_AND_ASSIGN(UnsignedLeb128EncodingVector);
+};
+
+}  // namespace art
+
+#endif  // ART_COMPILER_LEB128_ENCODER_H_