/
buffer.go
49 lines (42 loc) · 1.28 KB
/
buffer.go
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package machine
const bufferSize = 128
//go:volatile
type volatileByte byte
// RingBuffer is ring buffer implementation inspired by post at
// https://www.embeddedrelated.com/showthread/comp.arch.embedded/77084-1.php
//
// It has some limitations currently due to how "volatile" variables that are
// members of a struct are not compiled correctly by TinyGo.
// See https://github.com/tinygo-org/tinygo/issues/151 for details.
type RingBuffer struct {
rxbuffer [bufferSize]volatileByte
head volatileByte
tail volatileByte
}
// NewRingBuffer returns a new ring buffer.
func NewRingBuffer() *RingBuffer {
return &RingBuffer{}
}
// Used returns how many bytes in buffer have been used.
func (rb *RingBuffer) Used() uint8 {
return uint8(rb.head - rb.tail)
}
// Put stores a byte in the buffer. If the buffer is already
// full, the method will return false.
func (rb *RingBuffer) Put(val byte) bool {
if rb.Used() != bufferSize {
rb.head++
rb.rxbuffer[rb.head%bufferSize] = volatileByte(val)
return true
}
return false
}
// Get returns a byte from the buffer. If the buffer is empty,
// the method will return a false as the second value.
func (rb *RingBuffer) Get() (byte, bool) {
if rb.Used() != 0 {
rb.tail++
return byte(rb.rxbuffer[rb.tail%bufferSize]), true
}
return 0, false
}