LCOV - code coverage report
Current view: directory - objdir/dist/include/mozilla - RangedPtr.h (source / functions) Found Hit Coverage
Test: app.info Lines: 78 78 100.0 %
Date: 2012-06-02 Functions: 54 54 100.0 %

       1                 : /* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*-
       2                 :  * vim: set ts=8 sw=4 et tw=99 ft=cpp:
       3                 :  *
       4                 :  * ***** BEGIN LICENSE BLOCK *****
       5                 :  * Version: MPL 1.1/GPL 2.0/LGPL 2.1
       6                 :  *
       7                 :  * The contents of this file are subject to the Mozilla Public License Version
       8                 :  * 1.1 (the "License"); you may not use this file except in compliance with
       9                 :  * the License. You may obtain a copy of the License at:
      10                 :  * http://www.mozilla.org/MPL/
      11                 :  *
      12                 :  * Software distributed under the License is distributed on an "AS IS" basis,
      13                 :  * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
      14                 :  * for the specific language governing rights and limitations under the
      15                 :  * License.
      16                 :  *
      17                 :  * The Original Code is Mozilla Code.
      18                 :  *
      19                 :  * The Initial Developer of the Original Code is
      20                 :  *   The Mozilla Foundation
      21                 :  * Portions created by the Initial Developer are Copyright (C) 2011
      22                 :  * the Initial Developer. All Rights Reserved.
      23                 :  *
      24                 :  * Contributor(s):
      25                 :  *   Jeff Walden <jwalden+code@mit.edu> (original author)
      26                 :  *
      27                 :  * Alternatively, the contents of this file may be used under the terms of
      28                 :  * either the GNU General Public License Version 2 or later (the "GPL"), or
      29                 :  * the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
      30                 :  * in which case the provisions of the GPL or the LGPL are applicable instead
      31                 :  * of those above. If you wish to allow use of your version of this file only
      32                 :  * under the terms of either the GPL or the LGPL, and not to allow others to
      33                 :  * use your version of this file under the terms of the MPL, indicate your
      34                 :  * decision by deleting the provisions above and replace them with the notice
      35                 :  * and other provisions required by the GPL or the LGPL. If you do not delete
      36                 :  * the provisions above, a recipient may use your version of this file under
      37                 :  * the terms of any one of the MPL, the GPL or the LGPL.
      38                 :  *
      39                 :  * ***** END LICENSE BLOCK ***** */
      40                 : 
      41                 : /*
      42                 :  * Implements a smart pointer asserted to remain within a range specified at
      43                 :  * construction.
      44                 :  */
      45                 : 
      46                 : #ifndef mozilla_RangedPtr_h_
      47                 : #define mozilla_RangedPtr_h_
      48                 : 
      49                 : #include "mozilla/Assertions.h"
      50                 : #include "mozilla/Attributes.h"
      51                 : #include "mozilla/Util.h"
      52                 : 
      53                 : namespace mozilla {
      54                 : 
      55                 : /*
      56                 :  * RangedPtr is a smart pointer restricted to an address range specified at
      57                 :  * creation.  The pointer (and any smart pointers derived from it) must remain
      58                 :  * within the range [start, end] (inclusive of end to facilitate use as
      59                 :  * sentinels).  Dereferencing or indexing into the pointer (or pointers derived
      60                 :  * from it) must remain within the range [start, end).  All the standard pointer
      61                 :  * operators are defined on it; in debug builds these operations assert that the
      62                 :  * range specified at construction is respected.
      63                 :  *
      64                 :  * In theory passing a smart pointer instance as an argument can be slightly
      65                 :  * slower than passing a T* (due to ABI requirements for passing structs versus
      66                 :  * passing pointers), if the method being called isn't inlined.  If you are in
      67                 :  * extremely performance-critical code, you may want to be careful using this
      68                 :  * smart pointer as an argument type.
      69                 :  *
      70                 :  * RangedPtr<T> intentionally does not implicitly convert to T*.  Use get() to
      71                 :  * explicitly convert to T*.  Keep in mind that the raw pointer of course won't
      72                 :  * implement bounds checking in debug builds.
      73                 :  */
      74                 : template <typename T>
      75                 : class RangedPtr
      76                 : {
      77                 :     T* ptr;
      78                 : 
      79                 : #ifdef DEBUG
      80                 :     T* const rangeStart;
      81                 :     T* const rangeEnd;
      82                 : #endif
      83                 : 
      84       699637705 :     void checkSanity() {
      85       699637705 :         MOZ_ASSERT(rangeStart <= ptr);
      86       699637705 :         MOZ_ASSERT(ptr <= rangeEnd);
      87       699637705 :     }
      88                 : 
      89                 :     /* Creates a new pointer for |ptr|, restricted to this pointer's range. */
      90       346691296 :     RangedPtr<T> create(T *ptr) const {
      91                 : #ifdef DEBUG
      92       346691296 :         return RangedPtr<T>(ptr, rangeStart, rangeEnd);
      93                 : #else
      94                 :         return RangedPtr<T>(ptr, NULL, size_t(0));
      95                 : #endif
      96                 :     }
      97                 : 
      98                 :   public:
      99       346691529 :     RangedPtr(T* p, T* start, T* end)
     100                 :       : ptr(p)
     101                 : #ifdef DEBUG
     102       346691529 :       , rangeStart(start), rangeEnd(end)
     103                 : #endif
     104                 :     {
     105       346691529 :         MOZ_ASSERT(rangeStart <= rangeEnd);
     106       346691529 :         checkSanity();
     107       346691529 :     }
     108        46653353 :     RangedPtr(T* p, T* start, size_t length)
     109                 :       : ptr(p)
     110                 : #ifdef DEBUG
     111        46653353 :       , rangeStart(start), rangeEnd(start + length)
     112                 : #endif
     113                 :     {
     114        45964685 :         MOZ_ASSERT(length <= size_t(-1) / sizeof(T));
     115        46653353 :         MOZ_ASSERT(uintptr_t(rangeStart) + length * sizeof(T) >= uintptr_t(rangeStart));
     116        46653353 :         checkSanity();
     117        46653353 :     }
     118                 : 
     119                 :     /* Equivalent to RangedPtr(p, p, length). */
     120         3889863 :     RangedPtr(T* p, size_t length)
     121                 :       : ptr(p)
     122                 : #ifdef DEBUG
     123         3889863 :       , rangeStart(p), rangeEnd(p + length)
     124                 : #endif
     125                 :     {
     126         3536511 :         MOZ_ASSERT(length <= size_t(-1) / sizeof(T));
     127         3889863 :         MOZ_ASSERT(uintptr_t(rangeStart) + length * sizeof(T) >= uintptr_t(rangeStart));
     128         3889863 :         checkSanity();
     129         3889863 :     }
     130                 : 
     131                 :     /* Equivalent to RangedPtr(arr, arr, N). */
     132                 :     template<size_t N>
     133                 :     RangedPtr(T arr[N])
     134                 :       : ptr(arr)
     135                 : #ifdef DEBUG
     136                 :       , rangeStart(arr), rangeEnd(arr + N)
     137                 : #endif
     138                 :     {
     139                 :       checkSanity();
     140                 :     }
     141                 : 
     142        43748632 :     T* get() const {
     143        43748632 :         return ptr;
     144                 :     }
     145                 : 
     146                 :     /*
     147                 :      * You can only assign one RangedPtr into another if the two pointers have
     148                 :      * the same valid range:
     149                 :      *
     150                 :      *   char arr1[] = "hi";
     151                 :      *   char arr2[] = "bye";
     152                 :      *   RangedPtr<char> p1(arr1, 2);
     153                 :      *   p1 = RangedPtr<char>(arr1 + 1, arr1, arr1 + 2); // works
     154                 :      *   p1 = RangedPtr<char>(arr2, 3);                  // asserts
     155                 :      */
     156          740726 :     RangedPtr<T>& operator=(const RangedPtr<T>& other) {
     157          740726 :         MOZ_ASSERT(rangeStart == other.rangeStart);
     158          740726 :         MOZ_ASSERT(rangeEnd == other.rangeEnd);
     159          740726 :         ptr = other.ptr;
     160          740726 :         checkSanity();
     161          740726 :         return *this;
     162                 :     }
     163                 : 
     164        25071908 :     RangedPtr<T> operator+(size_t inc) {
     165        23788571 :         MOZ_ASSERT(inc <= size_t(-1) / sizeof(T));
     166        25071908 :         MOZ_ASSERT(ptr + inc > ptr);
     167        25071908 :         return create(ptr + inc);
     168                 :     }
     169                 : 
     170       319655379 :     RangedPtr<T> operator-(size_t dec) {
     171       317397412 :         MOZ_ASSERT(dec <= size_t(-1) / sizeof(T));
     172       319655379 :         MOZ_ASSERT(ptr - dec < ptr);
     173       319655379 :         return create(ptr - dec);
     174                 :     }
     175                 : 
     176                 :     /*
     177                 :      * You can assign a raw pointer into a RangedPtr if the raw pointer is
     178                 :      * within the range specified at creation.
     179                 :      */
     180                 :     template <typename U>
     181                 :     RangedPtr<T>& operator=(U* p) {
     182                 :         *this = create(p);
     183                 :         return *this;
     184                 :     }
     185                 : 
     186                 :     template <typename U>
     187       301662234 :     RangedPtr<T>& operator=(const RangedPtr<U>& p) {
     188       301662234 :         MOZ_ASSERT(rangeStart <= p.ptr);
     189       301662234 :         MOZ_ASSERT(p.ptr <= rangeEnd);
     190       301662234 :         ptr = p.ptr;
     191       301662234 :         checkSanity();
     192       301662234 :         return *this;
     193                 :     }
     194                 : 
     195        25064455 :     RangedPtr<T>& operator++() {
     196        25064455 :         return (*this += 1);
     197                 :     }
     198                 : 
     199        24699281 :     RangedPtr<T> operator++(int) {
     200        24699281 :         RangedPtr<T> rcp = *this;
     201        24699281 :         ++*this;
     202                 :         return rcp;
     203                 :     }
     204                 : 
     205       276590326 :     RangedPtr<T>& operator--() {
     206       276590326 :         return (*this -= 1);
     207                 :     }
     208                 : 
     209                 :     RangedPtr<T> operator--(int) {
     210                 :         RangedPtr<T> rcp = *this;
     211                 :         --*this;
     212                 :         return rcp;
     213                 :     }
     214                 : 
     215        25071908 :     RangedPtr<T>& operator+=(size_t inc) {
     216        25071908 :         this->operator=<T>(*this + inc);
     217        25071908 :         return *this;
     218                 :     }
     219                 : 
     220       276590326 :     RangedPtr<T>& operator-=(size_t dec) {
     221       276590326 :         this->operator=<T>(*this - dec);
     222       276590326 :         return *this;
     223                 :     }
     224                 : 
     225         1964009 :     T& operator[](int index) const {
     226         1964009 :         MOZ_ASSERT(size_t(index > 0 ? index : -index) <= size_t(-1) / sizeof(T));
     227         1964009 :         return *create(ptr + index);
     228                 :     }
     229                 : 
     230       423010626 :     T& operator*() const {
     231       423010626 :         return *ptr;
     232                 :     }
     233                 : 
     234                 :     template <typename U>
     235         3951353 :     bool operator==(const RangedPtr<U>& other) const {
     236         3951353 :         return ptr == other.ptr;
     237                 :     }
     238                 :     template <typename U>
     239         3523005 :     bool operator!=(const RangedPtr<U>& other) const {
     240         3523005 :         return !(*this == other);
     241                 :     }
     242                 : 
     243                 :     template<typename U>
     244           63617 :     bool operator==(const U* u) const {
     245           63617 :         return ptr == u;
     246                 :     }
     247                 :     template<typename U>
     248                 :     bool operator!=(const U* u) const {
     249                 :         return !(*this == u);
     250                 :     }
     251                 : 
     252                 :     template <typename U>
     253        12850242 :     bool operator<(const RangedPtr<U>& other) const {
     254        12850242 :         return ptr < other.ptr;
     255                 :     }
     256                 :     template <typename U>
     257           13506 :     bool operator<=(const RangedPtr<U>& other) const {
     258           13506 :         return ptr <= other.ptr;
     259                 :     }
     260                 : 
     261                 :     template <typename U>
     262                 :     bool operator>(const RangedPtr<U>& other) const {
     263                 :         return ptr > other.ptr;
     264                 :     }
     265                 :     template <typename U>
     266         1166904 :     bool operator>=(const RangedPtr<U>& other) const {
     267         1166904 :         return ptr >= other.ptr;
     268                 :     }
     269                 : 
     270        42783791 :     size_t operator-(const RangedPtr<T>& other) const {
     271        42783791 :         MOZ_ASSERT(ptr >= other.ptr);
     272        42783791 :         return PointerRangeSize(other.ptr, ptr);
     273                 :     }
     274                 : 
     275                 :   private:
     276                 :     RangedPtr() MOZ_DELETE;
     277                 :     T* operator&() MOZ_DELETE;
     278                 :     operator T*() const MOZ_DELETE;
     279                 : };
     280                 : 
     281                 : } /* namespace mozilla */
     282                 : 
     283                 : #endif  /* mozilla_RangedPtr_h_ */

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