StringTableBuilder.h

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//===-- StringTableBuilder.h - String table building utility ------*- C++ -*-=//
//
//                     The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//

#ifndef LLVM_MC_STRINGTABLEBUILDER_H
#define LLVM_MC_STRINGTABLEBUILDER_H

#include "llvm/ADT/SmallString.h"
#include "llvm/ADT/StringMap.h"
#include <cassert>

namespace llvm {

/// \brief Utility for building string tables with deduplicated suffixes.
class StringTableBuilder {
  SmallString<256> StringTable;
  StringMap<size_t> StringIndexMap;

public:
  /// \brief Add a string to the builder. Returns a StringRef to the internal
  /// copy of s. Can only be used before the table is finalized.
  StringRef add(StringRef s) {
    assert(!isFinalized());
    return StringIndexMap.GetOrCreateValue(s, 0).getKey();
  }

  /// \brief Analyze the strings and build the final table. No more strings can
  /// be added after this point.
  void finalize();

  /// \brief Retrieve the string table data. Can only be used after the table
  /// is finalized.
  StringRef data() {
    assert(isFinalized());
    return StringTable;
  }

  /// \brief Get the offest of a string in the string table. Can only be used
  /// after the table is finalized.
  size_t getOffset(StringRef s) {
    assert(isFinalized());
    assert(StringIndexMap.count(s) && "String is not in table!");
    return StringIndexMap[s];
  }

private:
  bool isFinalized() {
    return !StringTable.empty();
  }
};

} // end llvm namespace

#endif