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#define _FILE_OFFSET_BITS 64
#include "FileBackedDiskDevice.h"
#include <cstring>
#include <sys/stat.h>
//#define FBBD_DEBUG
#define IGNORE_FILE_LENGTH // Useful for e.g /dev/hda2
RetainPtr<FileBackedDiskDevice> FileBackedDiskDevice::create(String&& image_path, unsigned block_size)
{
return adopt(*new FileBackedDiskDevice(move(image_path), block_size));
}
FileBackedDiskDevice::FileBackedDiskDevice(String&& image_path, unsigned block_size)
: m_image_path(move(image_path))
, m_block_size(block_size)
{
struct stat st;
int result = stat(m_image_path.characters(), &st);
ASSERT(result != -1);
m_file_length = st.st_size;
m_file = fopen(m_image_path.characters(), "r+");
}
FileBackedDiskDevice::~FileBackedDiskDevice()
{
}
unsigned FileBackedDiskDevice::block_size() const
{
return m_block_size;
}
bool FileBackedDiskDevice::read_block(unsigned index, byte* out) const
{
DiskOffset offset = index * m_block_size;
return read_internal(offset, block_size(), out);
}
bool FileBackedDiskDevice::write_block(unsigned index, const byte* data)
{
DiskOffset offset = index * m_block_size;
return write_internal(offset, block_size(), data);
}
bool FileBackedDiskDevice::read_internal(DiskOffset offset, unsigned length, byte* out) const
{
#ifndef IGNORE_FILE_LENGTH
if (offset + length >= m_fileLength)
return false;
#endif
#ifdef FBBD_DEBUG
printf("[FileBackedDiskDevice] Read device @ offset %llx, length %u\n", offset, length);
#endif
fseeko(m_file, offset, SEEK_SET);
unsigned nread = fread(out, sizeof(byte), length, m_file);
ASSERT(nread == length);
return true;
}
bool FileBackedDiskDevice::write_internal(DiskOffset offset, unsigned length, const byte* data)
{
#ifndef IGNORE_FILE_LENGTH
if (offset + length >= m_fileLength)
return false;
#endif
#ifdef FBBD_DEBUG
printf("[FileBackedDiskDevice] Write device @ offset %llx, length %u\n", offset, length);
#endif
fseeko(m_file, offset, SEEK_SET);
// size_t fwrite(const void *ptr, size_t size, size_t nmemb, FILE *stream);
unsigned nwritten = fwrite(data, sizeof(byte), length, m_file);
ASSERT(nwritten == length);
return true;
}
const char* FileBackedDiskDevice::class_name() const
{
return "FileBackedDiskDevice";
}
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