lyng/docs/Buffer.md

Binary Buffer

Buffers are effective unsigned byte arrays of fixed size. Buffers content is mutable, unlike its size. Buffers are comparable and implement [Array], thus [Collection] and [Iterable]. Buffer iterators return its contents as unsigned bytes converted to Int

Buffers needs to be imported with import lyng.buffer:

import lyng.buffer

assertEquals(5, Buffer("Hello").size)
>>> void

Constructing

There are a lo of ways to construct a buffer:

import lyng.buffer

// from string using utf8 encoding:
assertEquals( 5, Buffer("hello").size )

// from bytes, e.g. integers in range 0..255
assertEquals( 255, Buffer(1,2,3,255).last() )

// from whatever iterable that produces bytes, e.g.
// integers in 0..255 range:
assertEquals( 129, Buffer([1,2,129]).last() )

// Empty buffer of fixed size:
assertEquals(100, Buffer(100).size)
assertEquals(0, Buffer(100)[0])

// Note that you can use list iteral to create buffer with 1 byte:
assertEquals(1, Buffer([100]).size)
assertEquals(100, Buffer([100])[0])

>>> void

Accessing an modifying

Buffer implement [Array] and therefore can be accessed and modified with indexing:

import lyng.buffer
val b1 = Buffer( 1, 2, 3)
assertEquals( 2, b1[1] )
b1[0] = 199
assertEquals(199, b1[0])
>>> void

Buffer provides concatenation with another Buffer:

import lyng.buffer
val b = Buffer(101, 102)
assertEquals( Buffer(101, 102, 1, 2), b + [1,2])
>>> void

Please note that indexed bytes are readonly projection, e.g. you can't modify these with

Comparing

Buffers are comparable with other buffers:

import lyng.buffer
val b1 = Buffer(1, 2, 3)
val b2 = Buffer(1, 2, 3)
val b3 = Buffer(b2)

b3[0] = 101

assert( b3 > b1 )
assert( b2 == b1 )
// longer string with same prefix is considered bigger:
assert( b2 + "!".characters() > b1 )
// note that characters() provide Iterable of characters that 
// can be concatenated to Buffer

>>> void

Slicing

As with [List], it is possible to use ranges as indexes to slice a Buffer:

import lyng.buffer

val a = Buffer( 100, 101, 102, 103, 104, 105 )
assertEquals( a[ 0..1 ], Buffer(100, 101) )
assertEquals( a[ 0 ..< 2 ], Buffer(100, 101) )
assertEquals( a[  ..< 2 ], Buffer(100, 101) )
assertEquals( a[  4.. ], Buffer(104, 105) )
assertEquals( a[  2..3 ], Buffer(102, 103) )

>>> void

Members

name	meaning	type
size	size	Int
+=	add one or more elements	Any
+, union	union sets	Any
-, subtract	subtract sets	Any
*, intersect	subtract sets	Any
remove(items...)	remove one or more items	Range
contains(element)	check the element is in the list (1)

(1)

optimized implementation that override Iterable one

Also, it inherits methods from [Iterable].