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/*
* Copyright (C) 2013, 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.
*/
#ifndef LATINIME_MMAPPED_BUFFER_H
#define LATINIME_MMAPPED_BUFFER_H
#include <cerrno>
#include <fcntl.h>
#include <stdint.h>
#include <sys/mman.h>
#include <unistd.h>
#include "defines.h"
namespace latinime {
class MmappedBuffer {
public:
static MmappedBuffer* openBuffer(const char *const path, const int bufferOffset,
const int bufferSize, const bool isUpdatable) {
const int openMode = isUpdatable ? O_RDWR : O_RDONLY;
const int mmapFd = open(path, openMode);
if (mmapFd < 0) {
AKLOGE("DICT: Can't open the source. path=%s errno=%d", path, errno);
return 0;
}
const int pagesize = getpagesize();
const int offset = bufferOffset % pagesize;
int alignedOffset = bufferOffset - offset;
int alignedSize = bufferSize + offset;
const int protMode = isUpdatable ? PROT_READ | PROT_WRITE : PROT_READ;
void *const mmappedBuffer = mmap(0, alignedSize, protMode, MAP_PRIVATE, mmapFd,
alignedOffset);
if (mmappedBuffer == MAP_FAILED) {
AKLOGE("DICT: Can't mmap dictionary. errno=%d", errno);
close(mmapFd);
return 0;
}
uint8_t *const buffer = static_cast<uint8_t *>(mmappedBuffer) + offset;
if (!buffer) {
AKLOGE("DICT: buffer is null");
close(mmapFd);
return 0;
}
return new MmappedBuffer(buffer, bufferSize, mmappedBuffer, alignedSize, mmapFd,
isUpdatable);
}
~MmappedBuffer() {
int ret = munmap(mMmappedBuffer, mAlignedSize);
if (ret != 0) {
AKLOGE("DICT: Failure in munmap. ret=%d errno=%d", ret, errno);
}
ret = close(mMmapFd);
if (ret != 0) {
AKLOGE("DICT: Failure in close. ret=%d errno=%d", ret, errno);
}
}
AK_FORCE_INLINE uint8_t *getBuffer() const {
return mBuffer;
}
AK_FORCE_INLINE int getBufferSize() const {
return mBufferSize;
}
AK_FORCE_INLINE bool isUpdatable() const {
return mIsUpdatable;
}
private:
AK_FORCE_INLINE MmappedBuffer(uint8_t *const buffer, const int bufferSize,
void *const mmappedBuffer, const int alignedSize, const int mmapFd,
const bool isUpdatable)
: mBuffer(buffer), mBufferSize(bufferSize), mMmappedBuffer(mmappedBuffer),
mAlignedSize(alignedSize), mMmapFd(mmapFd), mIsUpdatable(isUpdatable) {}
DISALLOW_IMPLICIT_CONSTRUCTORS(MmappedBuffer);
uint8_t *const mBuffer;
const int mBufferSize;
void *const mMmappedBuffer;
const int mAlignedSize;
const int mMmapFd;
const bool mIsUpdatable;
};
}
#endif /* LATINIME_MMAPPED_BUFFER_H */
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