class IO::Memory

Overview

An IO that reads and writes from a buffer in memory.

The internal buffer can be resizeable and/or writeable depending on how an IO::Memory is constructed.

Defined in:

io/memory.cr

Constructors

Instance Method Summary

Instance methods inherited from class IO

<<(obj) : self <<, close close, closed? closed?, each_byte(&block) : Nil
each_byte each_byte, each_char(&block) : Nil
each_char each_char, each_line(*args, **options, &block : String -> ) : Nil
each_line(*args, **options) each_line, encoding : String encoding, flush flush, gets(delimiter : Char, limit : Int, chomp = false) : String?
gets(delimiter : Char, chomp = false) : String?
gets(chomp = true) : String?
gets(limit : Int, chomp = false) : String?
gets(delimiter : String, chomp = false) : String? gets, gets_to_end : String gets_to_end, peek : Bytes? peek, pos pos, pos=(value) pos=, print(*objects : UNDERSCORE) : Nil
print(obj) : Nil print, printf(format_string, *args) : Nil
printf(format_string, args : Array | Tuple) : Nil printf, puts(*objects : UNDERSCORE) : Nil
puts : Nil
puts(obj) : Nil
puts(string : String) : Nil puts, read(slice : Bytes) read, read_at(offset, bytesize, &block) read_at, read_byte : UInt8? read_byte, read_bytes(type, format : IO::ByteFormat = IO::ByteFormat::SystemEndian) read_bytes, read_char : Char? read_char, read_fully(slice : Bytes) read_fully, read_fully?(slice : Bytes) read_fully?, read_line(*args, **options) : String read_line, read_string(bytesize : Int) : String read_string, read_utf8(slice : Bytes) read_utf8, read_utf8_byte read_utf8_byte, rewind rewind, seek(offset, whence : Seek = Seek::Set) seek, set_encoding(encoding : String, invalid : Symbol? = nil) set_encoding, skip(bytes_count : Int) : Nil skip, skip_to_end : Nil skip_to_end, tell tell, tty? : Bool tty?, write(slice : Bytes) : Nil write, write_byte(byte : UInt8) write_byte, write_bytes(object, format : IO::ByteFormat = IO::ByteFormat::SystemEndian) write_bytes, write_utf8(slice : Bytes) write_utf8

Class methods inherited from class IO

copy(src, dst, limit : Int) : UInt64
copy(src, dst) : UInt64 copy, pipe(read_blocking = false, write_blocking = false) : Tuple(IO::FileDescriptor, IO::FileDescriptor)
pipe(read_blocking = false, write_blocking = false, &block) pipe

Instance methods inherited from class Reference

==(other : self)
==(other : JSON::Any)
==(other : YAML::Any)
==(other) ==, dup dup, hash(hasher) hash, inspect(io : IO) : Nil inspect, object_id : UInt64 object_id, pretty_print(pp) : Nil pretty_print, same?(other : Reference)
same?(other : Nil) same?, to_s(io : IO) : Nil to_s

Constructor methods inherited from class Reference

new new

Instance methods inherited from class Object

!=(other) !=, !~(other) !~, ==(other) ==, ===(other : JSON::Any)
===(other : YAML::Any)
===(other) ===, =~(other) =~, class class, dup dup, hash(hasher)
hash hash, inspect(io : IO) : Nil
inspect : String inspect, itself itself, not_nil! not_nil!, pretty_inspect(width = 79, newline = "\n", indent = 0) : String pretty_inspect, pretty_print(pp : PrettyPrint) : Nil pretty_print, tap(&block) tap, to_json(io : IO)
to_json to_json, to_pretty_json(indent : String = " ")
to_pretty_json(io : IO, indent : String = " ") to_pretty_json, to_s : String
to_s(io : IO) : Nil to_s, to_yaml(io : IO)
to_yaml to_yaml, try(&block) try, unsafe_as(type : T.class) forall T unsafe_as

Constructor methods inherited from class Object

from_json(string_or_io, root : String) : self
from_json(string_or_io) : self from_json, from_yaml(string_or_io : String | IO) : self from_yaml

Constructor Detail

def self.new(capacity : Int = 64) #

Creates an empty, resizeable and writeable IO::Memory with the given initialize capactiy for the internal buffer.

io = IO::Memory.new
slice = Bytes.new(1)
io.pos         # => 0
io.read(slice) # => 0
slice          # => Bytes[0]

[View source]
def self.new(string : String) #

Creates an IO::Memory whose contents are the exact contents of string. The created IO::Memory is non-resizeable and non-writeable.

The IO starts at position zero for reading.

io = IO::Memory.new "hello"
io.pos        # => 0
io.gets(2)    # => "he"
io.print "hi" # raises IO::Error

[View source]
def self.new(slice : Bytes, writeable = true) #

Creates an IO::Memory that will read, and optionally write, from/to the given slice. The created IO::Memory is non-resizeable.

The IO starts at position zero for reading.

slice = Slice.new(6) { |i| ('a'.ord + i).to_u8 }
io = IO::Memory.new slice, writeable: false
io.pos            # => 0
io.read(slice)    # => 6
String.new(slice) # => "abcdef"

[View source]

Instance Method Detail

def buffer : Pointer(UInt8) #

Returns the internal buffer as a Pointer(UInt8).


[View source]
def bytesize : Int32 #

Same as #size.


[View source]
def clear #

Clears the internal buffer and resets the position to zero. Raises if this IO::Memory is non-resizeable.

io = IO::Memory.new
io << "abc"
io.rewind
io.gets(1) # => "a"
io.clear
io.pos         # => 0
io.gets_to_end # => ""

io = IO::Memory.new "hello"
io.clear # raises IO::Error

[View source]
def close #

Closes this IO. Further operations on this IO will raise an IO::Error.

io = IO::Memory.new "hello"
io.close
io.gets_to_end # raises IO::Error (closed stream)

[View source]
def closed? : Bool #

Determines if this IO is closed.

io = IO::Memory.new "hello"
io.closed? # => false
io.close
io.closed? # => true

[View source]
def empty? #

Returns true if this IO::Memory has no contents.

io = IO::Memory.new
io.empty? # => true
io.print "hello"
io.empty? # => false

[View source]
def pos : Int32 #

Returns the current position (in bytes) of this IO.

io = IO::Memory.new "hello"
io.pos     # => 0
io.gets(2) # => "he"
io.pos     # => 2

[View source]
def pos=(value) #

Sets the current position (in bytes) of this IO.

io = IO::Memory.new "hello"
io.pos = 3
io.gets # => "lo"

[View source]
def read(slice : Bytes) #

See IO#read(slice).


[View source]
def read_at(offset, bytesize, &block) #

Yields an IO::Memory to read a section of this IO's buffer.

During the block duration self becomes read-only, so multiple concurrent open are allowed.


[View source]
def rewind #

Rewinds this IO to the initial position (zero).

io = IO::Memory.new "hello"
io.gets(2) # => "he"
io.rewind
io.gets(2) # => "he"

[View source]
def seek(offset, whence : Seek = Seek::Set) #

Seeks to a given offset (in bytes) according to the whence argument.

io = IO::Memory.new("abcdef")
io.gets(3) # => "abc"
io.seek(1, IO::Seek::Set)
io.gets(2) # => "bc"
io.seek(-1, IO::Seek::Current)
io.gets(1) # => "c"

[View source]
def size : Int32 #

Returns the total number of bytes in this IO.

io = IO::Memory.new "hello"
io.size # => 5

[View source]
def to_s(io : IO) : Nil #

Appends this internal buffer to the given IO.


[View source]
def to_s : String #

Returns a new String that contains the contents of the internal buffer.

io = IO::Memory.new
io.print 1, 2, 3
io.to_s # => "123"

[View source]
def to_slice : Bytes #

Returns the underlying bytes.

io = IO::Memory.new
io.print "hello"

io.to_slice # => Bytes[104, 101, 108, 108, 111]

[View source]
def write(slice : Bytes) : Nil #

See IO#write(slice). Raises if this IO::Memory is non-writeable, or if it's non-resizeable and a resize is needed.


[View source]
def write_byte(byte : UInt8) #

See IO#write_byte. Raises if this IO::Memory is non-writeable, or if it's non-resizeable and a resize is needed.


[View source]