72 lines
1.7 KiB
Go
72 lines
1.7 KiB
Go
package graphvent
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import (
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"fmt"
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)
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type Message struct {
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Node NodeID
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Signal Signal
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}
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type MessageQueue struct {
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out chan Message
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in chan Message
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buffer []Message
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write_cursor int
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read_cursor int
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}
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func (queue *MessageQueue) ProcessIncoming(message Message) {
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if (queue.write_cursor + 1) == queue.read_cursor || ((queue.write_cursor + 1) == len(queue.buffer) && queue.read_cursor == 0) {
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fmt.Printf("Growing queue from %d to %d\n", len(queue.buffer), len(queue.buffer)*2)
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new_buffer := make([]Message, len(queue.buffer) * 2)
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copy(new_buffer, queue.buffer[queue.read_cursor:])
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first_chunk := len(queue.buffer) - queue.read_cursor
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copy(new_buffer[first_chunk:], queue.buffer[0:queue.write_cursor])
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queue.write_cursor = len(queue.buffer) - 1
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queue.read_cursor = 0
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queue.buffer = new_buffer
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}
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queue.buffer[queue.write_cursor] = message
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queue.write_cursor += 1
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if queue.write_cursor >= len(queue.buffer) {
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queue.write_cursor = 0
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}
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}
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func NewMessageQueue(initial int) (chan<- Message, <-chan Message) {
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queue := MessageQueue{
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out: make(chan Message, 0),
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in: make(chan Message, 0),
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buffer: make([]Message, initial),
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write_cursor: 0,
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read_cursor: 0,
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}
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go func(queue *MessageQueue) {
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for true {
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if queue.write_cursor != queue.read_cursor {
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select {
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case incoming := <-queue.in:
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queue.ProcessIncoming(incoming)
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case queue.out <- queue.buffer[queue.read_cursor]:
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queue.read_cursor += 1
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if queue.read_cursor >= len(queue.buffer) {
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queue.read_cursor = 0
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}
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}
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} else {
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message := <-queue.in
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queue.ProcessIncoming(message)
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}
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}
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}(&queue)
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return queue.in, queue.out
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}
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