72 lines
2.2 KiB
C++
72 lines
2.2 KiB
C++
|
/*
|
||
|
|
* Copyright (C) 2018 The Android Open Source Project
|
||
|
|
*
|
||
|
|
* 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.
|
||
|
|
*/
|
||
|
|
|
||
|
|
#include "android-base/mapped_file.h"
|
||
|
|
|
||
|
|
namespace android {
|
||
|
|
namespace base {
|
||
|
|
|
||
|
|
static off64_t InitPageSize() {
|
||
|
|
#if defined(_WIN32)
|
||
|
|
SYSTEM_INFO si;
|
||
|
|
GetSystemInfo(&si);
|
||
|
|
return si.dwAllocationGranularity;
|
||
|
|
#else
|
||
|
|
return sysconf(_SC_PAGE_SIZE);
|
||
|
|
#endif
|
||
|
|
}
|
||
|
|
|
||
|
|
std::unique_ptr<MappedFile> MappedFile::FromFd(int fd, off64_t offset, size_t length, int prot) {
|
||
|
|
static off64_t page_size = InitPageSize();
|
||
|
|
size_t slop = offset % page_size;
|
||
|
|
off64_t file_offset = offset - slop;
|
||
|
|
off64_t file_length = length + slop;
|
||
|
|
|
||
|
|
#if defined(_WIN32)
|
||
|
|
HANDLE handle =
|
||
|
|
CreateFileMapping(reinterpret_cast<HANDLE>(_get_osfhandle(fd)), nullptr,
|
||
|
|
(prot & PROT_WRITE) ? PAGE_READWRITE : PAGE_READONLY, 0, 0, nullptr);
|
||
|
|
if (handle == nullptr) return nullptr;
|
||
|
|
void* base = MapViewOfFile(handle, (prot & PROT_WRITE) ? FILE_MAP_ALL_ACCESS : FILE_MAP_READ, 0,
|
||
|
|
file_offset, file_length);
|
||
|
|
if (base == nullptr) {
|
||
|
|
CloseHandle(handle);
|
||
|
|
return nullptr;
|
||
|
|
}
|
||
|
|
return std::unique_ptr<MappedFile>(
|
||
|
|
new MappedFile{static_cast<char*>(base), length, slop, handle});
|
||
|
|
#else
|
||
|
|
void* base = mmap(nullptr, file_length, prot, MAP_SHARED, fd, file_offset);
|
||
|
|
if (base == MAP_FAILED) return nullptr;
|
||
|
|
return std::unique_ptr<MappedFile>(new MappedFile{static_cast<char*>(base), length, slop});
|
||
|
|
#endif
|
||
|
|
}
|
||
|
|
|
||
|
|
MappedFile::~MappedFile() {
|
||
|
|
#if defined(_WIN32)
|
||
|
|
if (base_ != nullptr) UnmapViewOfFile(base_);
|
||
|
|
if (handle_ != nullptr) CloseHandle(handle_);
|
||
|
|
#else
|
||
|
|
if (base_ != nullptr) munmap(base_, size_);
|
||
|
|
#endif
|
||
|
|
|
||
|
|
base_ = nullptr;
|
||
|
|
offset_ = size_ = 0;
|
||
|
|
}
|
||
|
|
|
||
|
|
} // namespace base
|
||
|
|
} // namespace android
|