OSX/libsecurity_cdsa_utilities/lib/constdata.h

   1 /*
   2  * Copyright (c) 2000-2001,2003-2004,2006,2011,2014 Apple Inc. All Rights Reserved.
   3  *
   4  * @APPLE_LICENSE_HEADER_START@
   5  *
   6  * This file contains Original Code and/or Modifications of Original Code
   7  * as defined in and that are subject to the Apple Public Source License
   8  * Version 2.0 (the 'License'). You may not use this file except in
   9  * compliance with the License. Please obtain a copy of the License at
  10  * http://www.opensource.apple.com/apsl/ and read it before using this
  11  * file.
  12  *
  13  * The Original Code and all software distributed under the License are
  14  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  15  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
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  22  */
  23
  24
  25 //
  26 // constdata - shared constant binary data objects
  27 //
  28 #ifndef _H_CONSTDATA
  29 #define _H_CONSTDATA
  30
  31 #include <security_utilities/utilities.h>
  32 #include <security_utilities/refcount.h>
  33
  34
  35 namespace Security {
  36
  37
  38 //
  39 // ConstData represents a contiguous, binary blob of constant data.
  40 // Assignment is by sharing (thus cheap).
  41 // ConstData is a (constant) Dataoid type.
  42 //
  43 class ConstData {
  44 private:
  45     class Blob : public RefCount {
  46     public:
  47         Blob() : mData(NULL), mSize(0) { }
  48         Blob(const void *base, size_t size, bool takeOwnership = false);
  49         ~Blob()         { delete[] reinterpret_cast<const char *>(mData); }
  50
  51         const void *data() const        { return mData; }
  52         size_t length() const           { return mSize; }
  53
  54     private:
  55         const void *mData;
  56         size_t mSize;
  57     };
  58
  59 public:
  60     ConstData() { }             //@@@ use a nullBlob?
  61     ConstData(const void *base, size_t size, bool takeOwnership = false)
  62         : mBlob(new Blob(base, size, takeOwnership)) { }
  63
  64     template <class T>
  65     static ConstData wrap(const T &obj, bool takeOwnership)
  66     { return ConstData(&obj, sizeof(obj), takeOwnership); }
  67
  68 public:
  69     const void *data() const    { return mBlob ? mBlob->data() : NULL; }
  70     size_t length() const               { return mBlob ? mBlob->length() : 0; }
  71
  72     operator bool() const               { return mBlob; }
  73     bool operator !() const             { return !mBlob; }
  74
  75     template <class T> operator const T *() const
  76     { return reinterpret_cast<const T *>(data()); }
  77
  78     template <class T> const T &as() const
  79     { return *static_cast<const T *>(reinterpret_cast<const T *>(data())); }
  80
  81 private:
  82     RefPointer<Blob> mBlob;
  83 };
  84
  85
  86 }       // end namespace Security
  87
  88
  89 #endif //_H_CONSTDATA