profuse/MappedFile.cpp
ksherlock b660593d25 ProDOS/Posix Exceptions
git-svn-id: https://profuse.googlecode.com/svn/branches/v2@124 aa027e90-d47c-11dd-86d7-074df07e0730
2009-12-02 01:19:34 +00:00

241 lines
5.4 KiB
C++

#include "MappedFile.h"
#include "Exception.h"
#include <cerrno>
#include <cstdlib>
#include <cstring>
#include <unistd.h>
#include <fcntl.h>
#include <sys/mman.h>
#include "auto.h"
using namespace ProFUSE;
MappedFile::MappedFile(const char *name, bool readOnly)
{
#undef __METHOD__
#define __METHOD__ "MappedFile::MappedFile"
// if unable to open as read/write, open as read-only.
auto_fd fd;
if (!readOnly)
{
fd.reset(::open(name, O_RDWR));
}
if (fd < 0)
{
fd.reset(::open(name, O_RDONLY));
readOnly = true;
}
if (fd < 0)
{
throw POSIXException(__METHOD__ ": Unable to open file.", errno);
}
// init may throw; auto_fd guarantees the file will be closed if that happens.
init(fd, readOnly);
fd.release();
}
// does NOT close fd on failure.
MappedFile::MappedFile(int fd, bool readOnly)
{
init(fd, readOnly);
}
MappedFile::MappedFile(const char *name, size_t size)
{
#undef __METHOD__
#define __METHOD__ "MappedFile::MappedFile"
_fd = -1;
_map = MAP_FAILED;
_size = size;
_readOnly = false;
_encoding = ProDOSOrder;
auto_fd fd(::open(name, O_CREAT | O_TRUNC | O_RDWR, 0644));
if (fd < 0)
throw POSIXException(__METHOD__ ": Unable to create file.", errno);
// TODO -- is ftruncate portable?
if (::ftruncate(fd, _size) < 0)
{
throw POSIXException(__METHOD__ ": Unable to truncate file.", errno);
}
//_map = ::mmap(NULL, _size, PROT_READ | PROT_WRITE, MAP_FILE | MAP_SHARED, _fd, 0);
auto_map map(
fd,
_size,
PROT_READ | PROT_WRITE,
MAP_FILE | MAP_SHARED
);
if (map == MAP_FAILED) throw POSIXException(__METHOD__ ": Unable to map file.", errno);
_fd = fd.release();
_map = map.release();
}
MappedFile::~MappedFile()
{
if (_map != MAP_FAILED) ::munmap(_map, _size);
if (_fd >= 0) ::close(_fd);
}
// does NOT close f on exception.
void MappedFile::init(int f, bool readOnly)
{
#undef __METHOD__
#define __METHOD__ "MappedFile::init"
//auto_fd fd(f);
_fd = -1;
_map = MAP_FAILED;
_offset = 0;
_blocks = 0;
_size = 0;
_readOnly = readOnly;
_encoding = ProDOSOrder;
_size = ::lseek(f, 0, SEEK_END);
if (_size < 0)
throw POSIXException(__METHOD__ ": Unable to determine file size.", errno);
/*
_map = ::mmap(NULL, _size, readOnly ? PROT_READ : PROT_READ | PROT_WRITE,
MAP_FILE | MAP_SHARED, fd, 0);
*/
auto_map map(
f,
_size,
readOnly ? PROT_READ : PROT_READ | PROT_WRITE,
readOnly ? MAP_FILE : MAP_FILE | MAP_SHARED
);
if (map == MAP_FAILED) throw POSIXException(__METHOD__ ": Unable to map file.", errno);
_fd = f;
_map = map.release();
}
const unsigned MappedFile::DOSMap[] = {
0x00, 0x0e, 0x0d, 0x0c,
0x0b, 0x0a, 0x09, 0x08,
0x07, 0x06, 0x05, 0x04,
0x03, 0x02, 0x01, 0x0f
};
void MappedFile::readBlock(unsigned block, void *bp)
{
#undef __METHOD__
#define __METHOD__ "MappedFile::readBlock"
if (block >= _blocks) throw Exception(__METHOD__ ": Invalid block number.");
if (bp == 0) throw Exception(__METHOD__ ": Invalid address.");
switch(_encoding)
{
case ProDOSOrder:
{
size_t address = block * 512;
std::memcpy(bp, (uint8_t *)_map + _offset + address, 512);
}
break;
case DOSOrder:
{
unsigned track = (block & ~0x07) << 9;
unsigned sector = (block & 0x07) << 1;
for (unsigned i = 0; i < 2; ++i)
{
size_t address = track | (DOSMap[sector+i] << 8);
std::memcpy(bp, (uint8_t *)_map + _offset + address, 256);
bp = (uint8_t *)bp + 256;
}
}
break;
default:
throw Exception(__METHOD__ ": Unsupported Encoding.");
}
}
void MappedFile::writeBlock(unsigned block, const void *bp)
{
#undef __METHOD__
#define __METHOD__ "MappedFile::writeBlock"
if (block > _blocks) throw Exception(__METHOD__ ": Invalid block number.");
if (_readOnly) throw Exception(__METHOD__ ": File is readonly.");
switch(_encoding)
{
case ProDOSOrder:
{
size_t address = block * 512;
std::memcpy((uint8_t *)_map + _offset + address , bp, 512);
}
break;
case DOSOrder:
{
unsigned track = (block & ~0x07) << 9;
unsigned sector = (block & 0x07) << 1;
for (unsigned i = 0; i < 2; ++i)
{
size_t address = track | (DOSMap[sector+i] << 8);
std::memcpy((uint8_t *)_map + _offset + address, bp, 256);
bp = (uint8_t *)bp + 256;
}
}
break;
default:
throw Exception(__METHOD__ ": Unsupported Encoding.");
}
}
void MappedFile::sync()
{
#undef __METHOD__
#define __METHOD__ "MappedFile::sync"
if (_readOnly) return;
if (::msync(_map, _size, MS_SYNC) < 0)
throw POSIXException(__METHOD__ ": msync error.", errno);
}
void MappedFile::reset()
{
_offset = 0;
_blocks = 0;
_encoding = ProDOSOrder;
}