kc3-lang/angle/src/compiler/translator/ImmutableStringBuilder.h

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• Hash : fbb1c792
  Author :
  Date : 2018-01-19T16:26:59
  

  Store symbol names as a ImmutableString
  
  This will enable compile-time initialization of built-in symbols as
  well as reducing copying strings.
  
  Most of the code that deals with names is changed to use
  ImmutableString where it makes sense to avoid conversions.
  
  The lexer/parser now allocate const char pointers into pool memory
  instead of allocating TStrings. These are then converted to
  ImmutableString upon entering TParseContext.
  
  BUG=angleproject:2267
  TEST=angle_unittests, angle_end2end_tests
  
  Change-Id: I244d6271ea1ecf7150d4f89dfa388a7745a1150c
  Reviewed-on: https://chromium-review.googlesource.com/881561
  Commit-Queue: Olli Etuaho <oetuaho@nvidia.com>
  Reviewed-by: Corentin Wallez <cwallez@chromium.org>
  

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• src/compiler/translator/ImmutableStringBuilder.h

• //
  // Copyright (c) 2018 The ANGLE Project Authors. All rights reserved.
  // Use of this source code is governed by a BSD-style license that can be
  // found in the LICENSE file.
  //
  // ImmutableStringBuilder.h: Stringstream-like utility for building pool allocated strings where the
  // maximum length is known in advance.
  //
  
  #ifndef COMPILER_TRANSLATOR_IMMUTABLESTRINGBUILDER_H_
  #define COMPILER_TRANSLATOR_IMMUTABLESTRINGBUILDER_H_
  
  #include "compiler/translator/ImmutableString.h"
  
  namespace sh
  {
  
  class ImmutableStringBuilder
  {
    public:
      ImmutableStringBuilder(size_t maxLength)
          : mPos(0u), mMaxLength(maxLength), mData(AllocateEmptyPoolCharArray(maxLength))
      {
      }
  
      ImmutableStringBuilder &operator<<(const ImmutableString &str);
  
      ImmutableStringBuilder &operator<<(const char *str);
  
      ImmutableStringBuilder &operator<<(const char &c);
  
      // This invalidates the ImmutableStringBuilder, so it should only be called once.
      operator ImmutableString();
  
      template <typename T>
      void appendHex(T number)
      {
          ASSERT(mData != nullptr);
          ASSERT(mPos + sizeof(T) * 2u <= mMaxLength);
          int index = static_cast<int>(sizeof(T)) * 2 - 1;
          // Loop through leading zeroes.
          while (((number >> (index * 4)) & 0xfu) == 0 && index > 0)
          {
              --index;
          }
          // Write the rest of the hex digits.
          while (index >= 0)
          {
              char digit     = static_cast<char>((number >> (index * 4)) & 0xfu);
              char digitChar = digit < 10 ? digit + '0' : digit + 'a';
              mData[mPos++]  = digitChar;
              --index;
          }
          return;
      }
  
    private:
      inline static char *AllocateEmptyPoolCharArray(size_t strLength)
      {
          size_t requiredSize = strLength + 1u;
          return reinterpret_cast<char *>(GetGlobalPoolAllocator()->allocate(requiredSize));
      }
  
      size_t mPos;
      size_t mMaxLength;
      char *mData;
  };
  
  }  // namespace sh
  
  #endif  // COMPILER_TRANSLATOR_IMMUTABLESTRINGBUILDER_H_
  

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