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/*
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* MemoryMap.cpp
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* Ottoman
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*
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* Created by Jens Alfke on 9/17/09.
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* Copyright 2009 Jens Alfke. All rights reserved.
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* BSD-Licensed: See the file "LICENSE.txt" for details.
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*/
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#include "MemoryMap.h"
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#include <errno.h>
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#include <stdio.h>
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#include <sys/mman.h>
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namespace Mooseyard {
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MemoryMap::~MemoryMap() {
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for (int i=0; i<_nRegions; i++)
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delete _regions[i];
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free(_regions);
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}
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void MemoryMap::mapRegion (off_t pos, size_t length) {
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size_t end = pos+length;
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for (int i=0; i<_nRegions; i++) {
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Region *region = _regions[i];
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if (region->position() <= pos) {
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if (end <= region->end())
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return; // found an existing region covering this range
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else if (region->setLength(end - region->position()))
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return; // able to grow the existing region
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}
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}
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// No existing region, so add a new one:
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Region *region = new Region(_file, pos,length);
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_regions = (Region**) realloc(_regions, (_nRegions+1)*sizeof(*_regions));
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_regions[_nRegions++] = region;
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}
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const void* MemoryMap::_at (off_t pos) const {
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for (int i=0; i<_nRegions; i++) {
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const void *ptr = _regions[i]->mappedPosition(pos);
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if (ptr)
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return ptr;
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}
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return NULL;
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}
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const void* MemoryMap::mappedPosition (off_t pos) const {
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const void *result = _at(pos);
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if (!result)
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throw File::Error("No memory mapped at this position");
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return result;
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}
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MemoryMap::Region::Region (File* file, off_t position, size_t length)
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:_file(file),
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_position(position),
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_length (length),
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_start( (const uint8_t*) ::mmap(NULL, length, PROT_READ, MAP_PRIVATE, file->_fd, position) )
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{
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printf("File#%i: Mapped (%6llu -- %6llu) --> %p\n", file->_fd, _position, end(), _start);
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if (_start==NULL || _start == MAP_FAILED) {
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_start = NULL;
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throw File::Error(errno, strerror(errno));
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}
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}
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MemoryMap::Region::~Region() {
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if (_start) {
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printf("File#%i: Unmapped (%6llu -- %6llu) from %p\n", _file->_fd, _position, end(), _start);
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::munmap((void*)_start,_length);
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}
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}
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bool MemoryMap::Region::setLength (size_t length) {
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if (length != _length) {
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printf("File#%i: Resiging (%6llu -- %6llu) from %lu to %lu ...",
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_file->_fd, _position, end(), _length,length);
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if (::mmap((void*)_start, length, PROT_READ, MAP_PRIVATE | MAP_FIXED, _file->_fd, _position) == MAP_FAILED) {
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printf("failed! errno=%i\n", errno);
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return false;
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}
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printf("OK\n");
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_length = length;
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}
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return true;
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}
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const void* MemoryMap::Region::mappedPosition (off_t pos) {
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if (pos >= _position && pos < end())
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return _start + (pos-_position);
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else
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return NULL;
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}
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}
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