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use errors;
use io;
use types;
export const sector_length: u64 = 512;
export fn lba(no: u64) size = {
return no * sector_length;
};
// Type that represents a region of a file mapped to memory
// which can be fetched or committed to.
export type sector = struct {
buf: []u8,
fd: io::file,
offs: u64,
length: u64,
};
// Creates a sector based on a file and a region
export fn map(fd: io::file, offs: u64, length: u64) sector = {
let self = sector {
buf = alloc([0...], length * sector_length),
fd = fd,
offs = offs,
length = length
};
return self;
};
// Finishes a sector and deallocates its related resources
export fn finish(self: *sector) void = {
free(self.buf);
};
// Fetches the content of a sector into the buffer
export fn fetch(self: *sector) (void | io::error) = {
io::seek(self.fd, (self.offs * sector_length): io::off, io::whence::SET)?;
io::read(self.fd, self.buf)?;
};
// Commits the content of a sector into the file
export fn commit(self: *sector) (void | io::error) = {
io::seek(self.fd, (self.offs * sector_length): io::off, io::whence::SET)?;
io::write(self.fd, self.buf)?;
};
// Commits the contents of a sector to another location in another file
export fn commit_at(self: *sector, fd: io::file, lba: u64) (void | io::error) = {
io::seek(fd, (lba * sector_length): io::off, io::whence::SET)?;
io::write(fd, self.buf)?;
};
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