The Tor Browser: toolkit/crashreporter/google-breakpad/src/common/memory

toolkit/crashreporter/google-breakpad/src/common/memory_range.h@b8a032363ba2 (annotated)

toolkit/crashreporter/google-breakpad/src/common/memory_range.h

Thu, 22 Jan 2015 13:21:57 +0100

author: Michael Schloh von Bennewitz <michael@schloh.com>
date: Thu, 22 Jan 2015 13:21:57 +0100
branch: TOR_BUG_9701
changeset 15: b8a032363ba2
permissions: -rw-r--r--

Incorporate requested changes from Mozilla in review:
https://bugzilla.mozilla.org/show_bug.cgi?id=1123480#c6

 // Copyright (c) 2011, Google Inc.
 // All rights reserved.
 //
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 // notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 // copyright notice, this list of conditions and the following disclaimer
 // in the documentation and/or other materials provided with the
 // distribution.
 //     * Neither the name of Google Inc. nor the names of its
 // contributors may be used to endorse or promote products derived from
 // this software without specific prior written permission.
 //
 // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 // "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 // LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
 // A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
 // OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 // SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 // LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 // DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 // THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 // memory_range.h: Define the google_breakpad::MemoryRange class, which
 // is a lightweight wrapper with a pointer and a length to encapsulate
 // a contiguous range of memory.
 #ifndef COMMON_MEMORY_RANGE_H_
 #define COMMON_MEMORY_RANGE_H_
 #include <stddef.h>
 #include "google_breakpad/common/breakpad_types.h"
 namespace google_breakpad {
 // A lightweight wrapper with a pointer and a length to encapsulate a
 // contiguous range of memory. It provides helper methods for checked
 // access of a subrange of the memory. Its implemementation does not
 // allocate memory or call into libc functions, and is thus safer to use
 // in a crashed environment.
 class MemoryRange {
  public:
   MemoryRange() : data_(NULL), length_(0) {}
   MemoryRange(const void* data, size_t length) {
     Set(data, length);
   }
   // Returns true if this memory range contains no data.
   bool IsEmpty() const {
     // Set() guarantees that |length_| is zero if |data_| is NULL.
     return length_ == 0;
   }
   // Resets to an empty range.
   void Reset() {
     data_ = NULL;
     length_ = 0;
   }
   // Sets this memory range to point to |data| and its length to |length|.
   void Set(const void* data, size_t length) {
     data_ = reinterpret_cast<const uint8_t*>(data);
     // Always set |length_| to zero if |data_| is NULL.
     length_ = data ? length : 0;
   }
   // Returns true if this range covers a subrange of |sub_length| bytes
   // at |sub_offset| bytes of this memory range, or false otherwise.
   bool Covers(size_t sub_offset, size_t sub_length) const {
     // The following checks verify that:
     // 1. sub_offset is within [ 0 .. length_ - 1 ]
     // 2. sub_offset + sub_length is within
     //    [ sub_offset .. length_ ]
     return sub_offset < length_ &&
            sub_offset + sub_length >= sub_offset &&
            sub_offset + sub_length <= length_;
   }
   // Returns a raw data pointer to a subrange of |sub_length| bytes at
   // |sub_offset| bytes of this memory range, or NULL if the subrange
   // is out of bounds.
   const void* GetData(size_t sub_offset, size_t sub_length) const {
     return Covers(sub_offset, sub_length) ? (data_ + sub_offset) : NULL;
   }
   // Same as the two-argument version of GetData() but uses sizeof(DataType)
   // as the subrange length and returns an |DataType| pointer for convenience.
   template <typename DataType>
   const DataType* GetData(size_t sub_offset) const {
     return reinterpret_cast<const DataType*>(
         GetData(sub_offset, sizeof(DataType)));
   }
   // Returns a raw pointer to the |element_index|-th element of an array
   // of elements of length |element_size| starting at |sub_offset| bytes
   // of this memory range, or NULL if the element is out of bounds.
   const void* GetArrayElement(size_t element_offset,
                               size_t element_size,
                               unsigned element_index) const {
     size_t sub_offset = element_offset + element_index * element_size;
     return GetData(sub_offset, element_size);
   }
   // Same as the three-argument version of GetArrayElement() but deduces
   // the element size using sizeof(ElementType) and returns an |ElementType|
   // pointer for convenience.
   template <typename ElementType>
   const ElementType* GetArrayElement(size_t element_offset,
                                      unsigned element_index) const {
     return reinterpret_cast<const ElementType*>(
         GetArrayElement(element_offset, sizeof(ElementType), element_index));
   }
   // Returns a subrange of |sub_length| bytes at |sub_offset| bytes of
   // this memory range, or an empty range if the subrange is out of bounds.
   MemoryRange Subrange(size_t sub_offset, size_t sub_length) const {
     return Covers(sub_offset, sub_length) ?
         MemoryRange(data_ + sub_offset, sub_length) : MemoryRange();
   }
   // Returns a pointer to the beginning of this memory range.
   const uint8_t* data() const { return data_; }
   // Returns the length, in bytes, of this memory range.
   size_t length() const { return length_; }
  private:
   // Pointer to the beginning of this memory range.
   const uint8_t* data_;
   // Length, in bytes, of this memory range.
   size_t length_;
 };
 }  // namespace google_breakpad
 #endif  // COMMON_MEMORY_RANGE_H_

The Tor Browser / annotate

toolkit/crashreporter/google-breakpad/src/common/memory_range.h@b8a032363ba2 (annotated)

toolkit/crashreporter/google-breakpad/src/common/memory_range.h