win: Add memory map range intersection helper

util/win/process_info.h

 // Copyright 2015 The Crashpad Authors. All rights reserved.
 //
 // Licensed under the Apache License, Version 2.0 (the "License");
 // you may not use this file except in compliance with the License.
 // You may obtain a copy of the License at
 //
 //     http://www.apache.org/licenses/LICENSE-2.0
 //
 // Unless required by applicable law or agreed to in writing, software
 // distributed under the License is distributed on an "AS IS" BASIS,
 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
 #ifndef CRASHPAD_UTIL_WIN_PROCESS_INFO_H_
 #define CRASHPAD_UTIL_WIN_PROCESS_INFO_H_
 
 #include <sys/types.h>
 #include <windows.h>
 
 #include <string>
 #include <vector>
 
 #include "base/basictypes.h"
 #include "util/misc/initialization_state_dcheck.h"
+#include "util/numeric/checked_range.h"
 #include "util/win/address_types.h"
 
 namespace crashpad {
 
 //! \brief Gathers information about a process given its `HANDLE`. This consists
 //!     primarily of information stored in the Process Environment Block.
 class ProcessInfo {
  public:
   //! \brief Contains information about a module loaded into a process.
   struct Module {
@@ skipping 86 matching lines @@
   //! \brief Retrieves the modules loaded into the target process.
   //!
   //! The modules are enumerated in initialization order as detailed in the
   //!     Process Environment Block. The main executable will always be the
   //!     first element.
   bool Modules(std::vector<Module>* modules) const;
 
   //! \brief Retrieves information about all pages mapped into the process.
   const std::vector<MemoryInfo>& MemoryInformation() const;
 
+  //! \brief Given a range to be read from the target process, returns a vector
+  //!     of ranges, representing the readable portions of the original range.
+  //!
+  //! \param[in] range The range being identified.
+  //!
+  //! \return A vector of ranges corresponding to the portion of \a range that
+  //!     is readable based on the memory map.
+  std::vector<CheckedRange<WinVMAddress, WinVMSize>> GetReadableRanges(
+      const CheckedRange<WinVMAddress, WinVMSize>& range) const;
+
  private:
   template <class Traits>
   friend bool GetProcessBasicInformation(HANDLE process,
                                          bool is_wow64,
                                          ProcessInfo* process_info,
                                          WinVMAddress* peb_address,
                                          WinVMSize* peb_size);
   template <class Traits>
   friend bool ReadProcessData(HANDLE process,
                               WinVMAddress peb_address_vmaddr,
                               ProcessInfo* process_info);
 
   friend bool ReadMemoryInfo(HANDLE process, ProcessInfo* process_info);
 
   pid_t process_id_;
   pid_t inherited_from_process_id_;
   std::wstring command_line_;
   WinVMAddress peb_address_;
   WinVMSize peb_size_;
   std::vector<Module> modules_;
   std::vector<MemoryInfo> memory_info_;
   bool is_64_bit_;
   bool is_wow64_;
   InitializationStateDcheck initialized_;
 
   DISALLOW_COPY_AND_ASSIGN(ProcessInfo);
 };
 
+//! \brief Given a memory map of a process, and a range to be read from the
+//!     target process, returns a vector of ranges, representing the readable
+//!     portions of the original range.
+//!
+//! This is a free function for testing, but prefer
+//! ProcessInfo::GetReadableRanges().
+std::vector<CheckedRange<WinVMAddress, WinVMSize>> GetReadableRangesOfMemoryMap(
+    const CheckedRange<WinVMAddress, WinVMSize>& range,
+    const std::vector<ProcessInfo::MemoryInfo>& memory_info);
+
 }  // namespace crashpad
 
 #endif  // CRASHPAD_UTIL_WIN_PROCESS_INFO_H_