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//! AFS Block I/O Interface
const errors = @import("shared").afs.errors;
const BlockError = errors.block.BlockError;
pub const BlockReader = struct {
Context: *anyopaque,
ReadFn: *const fn (context: *anyopaque, cell: u64, buffer: []u8) BlockError!void,
CellSize: u32,
TotalCells: u64,
pub fn readCell(self: *const BlockReader, cell: u64, buffer: []u8) BlockError!void {
if (cell >= self.TotalCells) {
return BlockError.OutOfBounds;
}
if (buffer.len < self.CellSize) {
return BlockError.InvalidCell;
}
return self.ReadFn(self.Context, cell, buffer);
}
pub fn readCells(self: *const BlockReader, start_cell: u64, buffer: []u8) BlockError!void {
const cells_to_read = buffer.len / self.CellSize;
var offset: usize = 0;
var cell = start_cell;
while (offset < buffer.len and cell < start_cell + cells_to_read) : ({
offset += self.CellSize;
cell += 1;
}) {
try self.readCell(cell, buffer[offset..][0..self.CellSize]);
}
}
};
pub const BlockWriter = struct {
Context: *anyopaque,
WriteFn: *const fn (context: *anyopaque, cell: u64, data: []const u8) BlockError!void,
CellSize: u32,
TotalCells: u64,
pub fn writeCell(self: *const BlockWriter, cell: u64, data: []const u8) BlockError!void {
if (cell >= self.TotalCells) {
return BlockError.OutOfBounds;
}
if (data.len < self.CellSize) {
return BlockError.InvalidCell;
}
return self.WriteFn(self.Context, cell, data);
}
pub fn writeCells(self: *const BlockWriter, start_cell: u64, data: []const u8) BlockError!void {
const cells_to_write = data.len / self.CellSize;
var offset: usize = 0;
var cell = start_cell;
while (offset < data.len and cell < start_cell + cells_to_write) : ({
offset += self.CellSize;
cell += 1;
}) {
try self.writeCell(cell, data[offset..][0..self.CellSize]);
}
}
};
pub const BlockDevice = struct {
Reader: BlockReader,
Writer: BlockWriter,
pub fn readCell(self: *const BlockDevice, cell: u64, buffer: []u8) BlockError!void {
return self.Reader.readCell(cell, buffer);
}
pub fn writeCell(self: *const BlockDevice, cell: u64, data: []const u8) BlockError!void {
return self.Writer.writeCell(cell, data);
}
};
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