third_party/WebKit/Source/wtf/ArrayPiece.h

   1 // Copyright 2014 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #ifndef ArrayPiece_h
   6 #define ArrayPiece_h
   7
   8 #include "wtf/Forward.h"
   9 #include "wtf/WTFExport.h"
  10
  11 namespace WTF {
  12
  13 // This class is for passing around un-owned bytes as a pointer + length.
  14 // It supports implicit conversion from several other data types.
  15 //
  16 // ArrayPiece has the concept of being "null". This is different from an empty
  17 // byte range. It is invalid to call methods other than isNull() on such
  18 // instances.
  19 //
  20 // IMPORTANT: The data contained by ArrayPiece is NOT OWNED, so caution must be
  21 //            taken to ensure it is kept alive.
  22 class WTF_EXPORT ArrayPiece {
  23 public:
  24     // Constructs a "null" ArrayPiece object.
  25     ArrayPiece();
  26
  27     ArrayPiece(void* data, unsigned byteLength);
  28
  29     // Constructs an ArrayPiece from the given ArrayBuffer. If the input is a
  30     // nullptr, then the constructed instance will be isNull().
  31     ArrayPiece(ArrayBuffer*);
  32     ArrayPiece(ArrayBufferView*);
  33
  34     bool isNull() const;
  35     void* data() const;
  36     unsigned char* bytes() const;
  37     unsigned byteLength() const;
  38
  39 protected:
  40     void initWithData(void* data, unsigned byteLength);
  41
  42 private:
  43     void initNull();
  44
  45     void* m_data;
  46     unsigned m_byteLength;
  47     bool m_isNull;
  48 };
  49
  50 } // namespace WTF
  51
  52 using WTF::ArrayPiece;
  53
  54 #endif // ArrayPiece_h