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/*
* Copyright (C) 2016 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_RUNTIME_STRING_REFERENCE_H_
#define ART_RUNTIME_STRING_REFERENCE_H_
#include <stdint.h>
#include "base/logging.h"
#include "dex_file-inl.h"
#include "utf-inl.h"
namespace art {
// A string is located by its DexFile and the string_ids_ table index into that DexFile.
struct StringReference {
StringReference(const DexFile* file, uint32_t index) : dex_file(file), string_index(index) { }
const char* GetStringData() const {
return dex_file->GetStringData(dex_file->GetStringId(string_index));
}
const DexFile* dex_file;
uint32_t string_index;
};
// Compare only the reference and not the string contents.
struct StringReferenceComparator {
bool operator()(const StringReference& a, const StringReference& b) {
if (a.dex_file != b.dex_file) {
return a.dex_file < b.dex_file;
}
return a.string_index < b.string_index;
}
};
// Compare the actual referenced string values. Used for string reference deduplication.
struct StringReferenceValueComparator {
bool operator()(StringReference sr1, StringReference sr2) const {
// Note that we want to deduplicate identical strings even if they are referenced
// by different dex files, so we need some (any) total ordering of strings, rather
// than references. However, the references should usually be from the same dex file,
// so we choose the dex file string ordering so that we can simply compare indexes
// and avoid the costly string comparison in the most common case.
if (sr1.dex_file == sr2.dex_file) {
// Use the string order enforced by the dex file verifier.
DCHECK_EQ(
sr1.string_index < sr2.string_index,
CompareModifiedUtf8ToModifiedUtf8AsUtf16CodePointValues(sr1.GetStringData(),
sr2.GetStringData()) < 0);
return sr1.string_index < sr2.string_index;
} else {
// Cannot compare indexes, so do the string comparison.
return CompareModifiedUtf8ToModifiedUtf8AsUtf16CodePointValues(sr1.GetStringData(),
sr2.GetStringData()) < 0;
}
}
};
} // namespace art
#endif // ART_RUNTIME_STRING_REFERENCE_H_