class MemoryIO

Overview

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

The internal buffer can be resizeable and/or writeable depending on how a MemoryIO is constructed.

Included Modules

Defined in:

io/memory_io.cr

Class Method Summary

Instance Method Summary

Instance methods inherited from module IO

<<(obj) : self <<, close close, cooked(&block) cooked, cooked! cooked!, each_byte
each_byte(&block)
each_byte
, each_char(&block)
each_char
each_char
, each_line(*args, &block)
each_line(*args)
each_line
, flush flush, gets(limit : Int) : String | Nil
gets(delimiter : Char, limit : Int) : String | Nil
gets(delimiter : Char) : String | Nil
gets : String | Nil
gets(delimiter : String) : String | Nil
gets
, gets_to_end : String gets_to_end, print(*objects : _) : Nil
print(obj) : Nil
print
, printf(format_string, args : Array | Tuple) : Nil
printf(format_string, *args) : Nil
printf
, puts : Nil
puts(*objects : _) : Nil
puts(string : String) : Nil
puts(obj) : Nil
puts
, raw(&block) raw, raw! raw!, read(slice : Slice(UInt8)) read, read_byte : UInt8 | Nil read_byte, read_bytes(type, format = IO::ByteFormat::SystemEndian : IO::ByteFormat) read_bytes, read_char : Char | Nil read_char, read_fully(slice : Slice(UInt8)) read_fully, read_line(*args) : String | Nil read_line, read_nonblock(size) read_nonblock, skip(bytes_count : Int) : Nil skip, tty? : Bool tty?, write(slice : Slice(UInt8)) : Nil write, write_byte(byte : UInt8) write_byte, write_bytes(object, format = IO::ByteFormat::SystemEndian : IO::ByteFormat) write_bytes

Class methods inherited from module IO

copy(src, dst) copy, pipe(read_blocking = false, write_blocking = false, &block)
pipe(read_blocking = false, write_blocking = false)
pipe
, select(read_ios, write_ios, error_ios, timeout_sec : LibC::TimeT | Int | Float | Nil)
select(read_ios, write_ios = nil, error_ios = nil)
select

Instance methods inherited from module JSON::Builder

json_array(&block) json_array, json_object(&block) json_object

Instance methods inherited from class Reference

! !, ==(other)
==(other : self)
==
, hash hash, inspect(io : IO) : Nil inspect, nil? nil?, object_id object_id, same?(other : Nil)
same?(other : Reference)
same?
, to_s(io : IO) : Nil to_s

Instance methods inherited from class Object

! !, !=(other) !=, !~(other) !~, ==(other) ==, ===(other) ===, =~(other) =~, class class, clone clone, crystal_type_id crystal_type_id, dup dup, hash hash, inspect
inspect(io : IO)
inspect
, itself itself, not_nil! not_nil!, tap(&block) tap, to_json to_json, to_pretty_json(io : IO)
to_pretty_json
to_pretty_json
, to_s
to_s(io : IO)
to_s
, to_yaml(io : IO)
to_yaml
to_yaml
, try(&block) try

Class methods inherited from class Object

==(other : Class) ==, ===(other) ===, cast(other) : self cast, from_json(string_or_io) from_json, from_yaml(string : String) from_yaml, hash hash, inspect(io) inspect, name : String name, to_s(io) to_s

Class Method Detail

def self.new(string : String) #

Creates a MemoryIO whose contents are the exact contents of string. The created MemoryIO is non-resizeable and non-writeable.

The IO starts at position zero for reading.

io = MemoryIO.new "hello"
io.pos        # => 0
io.gets(2)    # => "he"
io.print "hi" # raises

[View source]
def self.new(capacity = 64 : Int) #

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

io = MemoryIO.new
io.pos  # => 0
io.read # => ""

[View source]
def self.new(slice : Slice(UInt8), writeable = true) #

Creates a MemoryIO that will read, and optionally write, from/to the given slice. The created MemoryIO is non-resizeable.

The IO starts at position zero for reading.

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

[View source]

Instance Method Detail

def buffer #

Returns the internal buffer as a Pointer(UInt8).


[View source]
def bytesize #

Same as #size.


[View source]
def clear #

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

io = MemoryIO.new "hello"
io.gets(3) # => "hel"
io.clear
io.pos         # => 0
io.gets_to_end # => ""

[View source]
def close #

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

io = MemoryIO.new "hello"
io.close
io.gets_to_end # => IO::Error: closed stream

[View source]
def closed? #

Determines if this IO is closed.

io = MemoryIO.new "hello"
io.closed? # => false
io.close
io.closed? # => true

[View source]
def empty? #

Returns true if this MemoryIO has no contents.

io = MemoryIO.new
io.empty? # => true
io.print "hello"
io.empty? # => false

[View source]
def pos #

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

io = MemoryIO.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 = MemoryIO.new "hello"
io.pos = 3
io.gets # => "lo"

[View source]
def read(slice : Slice(UInt8)) #

[View source]
def rewind #

Rewinds this IO to the initial position (zero).

io = MemoryIO.new "hello"
io.gets(2) => "he"
io.rewind
io.gets(2) #=> "he"

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

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

io = MemoryIO.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 #

Returns the total number of bytes in this IO.

io = MemoryIO.new "hello"
io.size # => 5

[View source]
def tell #

Same as #pos.


[View source]
def to_s #

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

io = MemoryIO.new
io.print 1, 2, 3
io.to_s # => "123"

[View source]
def to_s(io) #

Appends this internal buffer to the given IO.


[View source]
def to_slice #

Returns a Slice over the internal buffer. Modifying the slice modifies the internal buffer.

io = MemoryIO.new "hello"
slice = io.to_slice
slice[0] = 97_u8
io.gets_to_end # => "aello"

[View source]
def write(slice : Slice(UInt8)) #

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


[View source]