cdsa/cdsa_utilities/constdata.h

   1 /*
   2  * Copyright (c) 2000-2001 Apple Computer, Inc. All Rights Reserved.
   3  *
   4  * The contents of this file constitute Original Code as defined in and are
   5  * subject to the Apple Public Source License Version 1.2 (the 'License').
   6  * You may not use this file except in compliance with the License. Please obtain
   7  * a copy of the License at http://www.apple.com/publicsource and read it before
   8  * using this file.
   9  *
  10  * This Original Code and all software distributed under the License are
  11  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER EXPRESS
  12  * OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES, INCLUDING WITHOUT
  13  * LIMITATION, ANY WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR
  14  * PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT. Please see the License for the
  15  * specific language governing rights and limitations under the License.
  16  */
  17
  18
  19 //
  20 // constdata - shared constant binary data objects
  21 //
  22 #ifndef _H_CONSTDATA
  23 #define _H_CONSTDATA
  24
  25 #include <Security/utilities.h>
  26 #include <Security/refcount.h>
  27
  28
  29 namespace Security {
  30
  31
  32 //
  33 // ConstData represents a contiguous, binary blob of constant data.
  34 // Assignment is by sharing (thus cheap).
  35 // ConstData is a (constant) Dataoid type.
  36 //
  37 class ConstData {
  38 private:
  39     class Blob : public RefCount {
  40     public:
  41         Blob() : mData(NULL), mSize(0) { }
  42         Blob(const void *base, size_t size, bool takeOwnership = false);
  43         ~Blob()         { delete[] reinterpret_cast<const char *>(mData); }
  44
  45         const void *data() const        { return mData; }
  46         size_t length() const           { return mSize; }
  47
  48     private:
  49         const void *mData;
  50         size_t mSize;
  51     };
  52
  53 public:
  54     ConstData() { }             //@@@ use a nullBlob?
  55     ConstData(const void *base, size_t size, bool takeOwnership = false)
  56         : mBlob(new Blob(base, size, takeOwnership)) { }
  57
  58     template <class T>
  59     static ConstData wrap(const T &obj, bool takeOwnership)
  60     { return ConstData(&obj, sizeof(obj), takeOwnership); }
  61
  62 public:
  63     const void *data() const    { return mBlob ? mBlob->data() : NULL; }
  64     size_t length() const               { return mBlob ? mBlob->length() : 0; }
  65
  66     operator bool() const               { return mBlob; }
  67     bool operator !() const             { return !mBlob; }
  68
  69     template <class T> operator const T *() const
  70     { return reinterpret_cast<const T *>(data()); }
  71
  72     template <class T> const T &as() const
  73     { return *static_cast<const T *>(reinterpret_cast<const T *>(data())); }
  74
  75 private:
  76     RefPointer<Blob> mBlob;
  77 };
  78
  79
  80 }       // end namespace Security
  81
  82
  83 #endif //_H_CONSTDATA