class YieldingWrapper
- YieldingWrapper
- IO
- Reference
- Object
Defined in:
app/io_helpers/yielding_wrapper.crConstructors
Instance Method Summary
-
#pos : UInt64
Returns the current position (in bytes) in this
IO
. -
#read(slice : Bytes)
Reads at most slice.size bytes from this
IO
into slice. -
#write(slice : Bytes) : Nil
Writes the contents of slice into this
IO
.
Constructor Detail
Instance Method Detail
def pos : UInt64
#
Description copied from class IO
Returns the current position (in bytes) in this IO
.
The IO
class raises on this method, but some subclasses, notable
IO::FileDescriptor
and IO::Memory
implement it.
File.write("testfile", "hello")
file = File.new("testfile")
file.pos # => 0
file.gets(2) # => "he"
file.pos # => 2
def read(slice : Bytes)
#
Description copied from class IO
Reads at most slice.size bytes from this IO
into slice.
Returns the number of bytes read, which is 0 if and only if there is no
more data to read (so checking for 0 is the way to detect end of file).
io = IO::Memory.new "hello"
slice = Bytes.new(4)
io.read(slice) # => 4
slice # => Bytes[104, 101, 108, 108]
io.read(slice) # => 1
slice # => Bytes[111, 101, 108, 108]
io.read(slice) # => 0
def write(slice : Bytes) : Nil
#
Description copied from class IO
Writes the contents of slice into this IO
.
io = IO::Memory.new
slice = Bytes.new(4) { |i| ('a'.ord + i).to_u8 }
io.write(slice)
io.to_s # => "abcd"