/*
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* Copyright (C) 2016 The Android Open Source Project
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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#ifndef ART_LIBDEXFILE_DEX_STRING_REFERENCE_H_
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#define ART_LIBDEXFILE_DEX_STRING_REFERENCE_H_
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#include <stdint.h>
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#include <android-base/logging.h>
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#include "dex/dex_file-inl.h"
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#include "dex/dex_file_reference.h"
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#include "dex/dex_file_types.h"
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#include "dex/utf-inl.h"
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namespace art {
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// A string is located by its DexFile and the string_ids_ table index into that DexFile.
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class StringReference : public DexFileReference {
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public:
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StringReference(const DexFile* file, dex::StringIndex index)
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: DexFileReference(file, index.index_) {}
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dex::StringIndex StringIndex() const {
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return dex::StringIndex(index);
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}
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const char* GetStringData() const {
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return dex_file->GetStringData(dex_file->GetStringId(StringIndex()));
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}
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};
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// Compare the actual referenced string values. Used for string reference deduplication.
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struct StringReferenceValueComparator {
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bool operator()(const StringReference& sr1, const StringReference& sr2) const {
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// Note that we want to deduplicate identical strings even if they are referenced
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// by different dex files, so we need some (any) total ordering of strings, rather
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// than references. However, the references should usually be from the same dex file,
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// so we choose the dex file string ordering so that we can simply compare indexes
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// and avoid the costly string comparison in the most common case.
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if (sr1.dex_file == sr2.dex_file) {
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// Use the string order enforced by the dex file verifier.
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DCHECK_EQ(
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sr1.index < sr2.index,
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CompareModifiedUtf8ToModifiedUtf8AsUtf16CodePointValues(sr1.GetStringData(),
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sr2.GetStringData()) < 0);
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return sr1.index < sr2.index;
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} else {
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// Cannot compare indexes, so do the string comparison.
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return CompareModifiedUtf8ToModifiedUtf8AsUtf16CodePointValues(sr1.GetStringData(),
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sr2.GetStringData()) < 0;
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}
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}
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};
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} // namespace art
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#endif // ART_LIBDEXFILE_DEX_STRING_REFERENCE_H_
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