jens@0: /*
jens@0:  *  MemoryMap.cpp
jens@0:  *  Ottoman
jens@0:  *
jens@0:  *  Created by Jens Alfke on 9/17/09.
jens@0:  *  Copyright 2009 Jens Alfke. All rights reserved.
jens@0:  *  BSD-Licensed: See the file "LICENSE.txt" for details.
jens@0:  */
jens@0: 
jens@0: #include "MemoryMap.h"
jens@0: 
jens@0: #include <errno.h>
jens@0: #include <stdio.h>
jens@0: #include <sys/mman.h>
jens@0: 
jens@0: namespace Mooseyard {
jens@0: 
jens@0:     MemoryMap::~MemoryMap() {
jens@0:         for (int i=0; i<_nRegions; i++)
jens@0:             delete _regions[i];
jens@0:         free(_regions);
jens@0:     }
jens@0: 
jens@0:     void MemoryMap::mapRegion (off_t pos, size_t length) {
jens@2:         off_t end = pos+length;
jens@0:         for (int i=0; i<_nRegions; i++) {
jens@0:             Region *region = _regions[i];
jens@0:             if (region->position() <= pos) {
jens@0:                 if (end <= region->end())
jens@0:                     return;     // found an existing region covering this range
jens@2:                 else if (region->setLength((size_t)(end - region->position())))
jens@0:                     return;     // able to grow the existing region
jens@0:             }
jens@0:         }
jens@0:         
jens@0:         // No existing region, so add a new one:
jens@0:         Region *region = new Region(_file, pos,length);
jens@0:         _regions = (Region**) realloc(_regions, (_nRegions+1)*sizeof(*_regions));
jens@0:         _regions[_nRegions++] = region;
jens@0:     }
jens@0: 
jens@0:     const void* MemoryMap::_at (off_t pos) const {
jens@0:         for (int i=0; i<_nRegions; i++) {
jens@0:             const void *ptr = _regions[i]->mappedPosition(pos);
jens@0:             if (ptr)
jens@0:                 return ptr;
jens@0:         }
jens@0:         return NULL;
jens@0:     }
jens@0:     
jens@0:     const void* MemoryMap::mappedPosition (off_t pos) const {
jens@0:         const void *result = _at(pos);
jens@0:         if (!result)
jens@0:             throw File::Error("No memory mapped at this position");
jens@0:         return result;
jens@0:     }
jens@0: 
jens@0:     
jens@0:     
jens@0:     
jens@0:     MemoryMap::Region::Region (File* file, off_t position, size_t length)
jens@0:     :_file(file),
jens@0:     _position(position),
jens@0:     _length (length),
jens@0:     _start( (const uint8_t*) ::mmap(NULL, length, PROT_READ, MAP_PRIVATE, file->_fd, position) )
jens@0:     {
jens@0:         printf("File#%i: Mapped (%6llu -- %6llu) --> %p\n", file->_fd, _position, end(), _start);
jens@0:         if (_start==NULL || _start == MAP_FAILED) {
jens@0:             _start = NULL;
jens@0:             throw File::Error(errno, strerror(errno));
jens@0:         }
jens@0:     }
jens@0:     
jens@0:     MemoryMap::Region::~Region() {
jens@0:         if (_start) {
jens@0:             printf("File#%i: Unmapped (%6llu -- %6llu) from %p\n", _file->_fd, _position, end(), _start);
jens@0:             ::munmap((void*)_start,_length);
jens@0:         }
jens@0:     }
jens@0:     
jens@0:     bool MemoryMap::Region::setLength (size_t length) {
jens@0:         if (length != _length) {
jens@0:             printf("File#%i: Resiging (%6llu -- %6llu) from %lu to %lu ...", 
jens@0:                    _file->_fd, _position, end(), _length,length);
jens@0:             if (::mmap((void*)_start, length, PROT_READ, MAP_PRIVATE | MAP_FIXED, _file->_fd, _position) == MAP_FAILED) {
jens@0:                 printf("failed! errno=%i\n", errno);
jens@0:                 return false;
jens@0:             }
jens@0:             printf("OK\n");
jens@0:             _length = length;
jens@0:         }
jens@0:         return true;
jens@0:     }
jens@0:     
jens@0:     const void* MemoryMap::Region::mappedPosition (off_t pos) {
jens@0:         if (pos >= _position && pos < end())
jens@0:             return _start + (pos-_position);
jens@0:         else
jens@0:             return NULL;
jens@0:     }
jens@0:     
jens@0:     
jens@0: }