class IO::Digest
inherits IO
¶
Wraps an IO by calculating a specified Digest on read or write operations.
Example¶
require "digest"
underlying_io = IO::Memory.new("foo")
io = IO::Digest.new(underlying_io, Digest::SHA256.new)
buffer = Bytes.new(256)
io.read(buffer)
io.final.hexstring # => "2c26b46b68ffc68ff99b453c1d30413413422d706483bfa0f98a5e886266e7ae"
Class methods¶
Methods¶
#read(slice : Bytes)
¶
(slice : Bytes)
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
#write(slice : Bytes) : Nil
¶
(slice : Bytes) : Nil
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"