Function create_file_device_path [src]

Creates a file device path from the existing device path and a file path.

Prototype

pub fn create_file_device_path(self: *DevicePath, allocator: Allocator, path: [:0]align(1) const u16) !*DevicePath

Parameters

self: *DevicePathallocator: Allocatorpath: [:0]align(1) const u16

Source

  pub fn create_file_device_path(self: *DevicePath, allocator: Allocator, path: [:0]align(1) const u16) !*DevicePath {
    const path_size = self.size();

    // 2 * (path.len + 1) for the path and its null terminator, which are u16s
    // DevicePath for the extra node before the end
    var buf = try allocator.alloc(u8, path_size + 2 * (path.len + 1) + @sizeOf(DevicePath));

    @memcpy(buf[0..path_size], @as([*]const u8, @ptrCast(self))[0..path_size]);

    // Pointer to the copy of the end node of the current chain, which is - 4 from the buffer
    // as the end node itself is 4 bytes (type: u8 + subtype: u8 + length: u16).
    var new = @as(*uefi.DevicePath.Media.FilePathDevicePath, @ptrCast(buf.ptr + path_size - 4));

    new.type = .media;
    new.subtype = .file_path;
    new.length = @sizeOf(uefi.DevicePath.Media.FilePathDevicePath) + 2 * (@as(u16, @intCast(path.len)) + 1);

    // The same as new.getPath(), but not const as we're filling it in.
    var ptr = @as([*:0]align(1) u16, @ptrCast(@as([*]u8, @ptrCast(new)) + @sizeOf(uefi.DevicePath.Media.FilePathDevicePath)));

    for (path, 0..) |s, i|
        ptr[i] = s;

    ptr[path.len] = 0;

    var end = @as(*uefi.DevicePath.End.EndEntireDevicePath, @ptrCast(@as(*DevicePath, @ptrCast(new)).next().?));
    end.type = .end;
    end.subtype = .end_entire;
    end.length = @sizeOf(uefi.DevicePath.End.EndEntireDevicePath);

    return @as(*DevicePath, @ptrCast(buf.ptr));
}  