combining_processor.go

package main

import (
	"bytes"
	"net"
)

type CombiningProcessor struct {
	first    net.IP
	last     net.IP
	next     net.IP
	value    string
	Emitter
}

func CombiningProcessorCreate() *CombiningProcessor {
	return &CombiningProcessor{
		first: net.IP{},
		last:  net.IP{},
		value: "",
	}
}

func (m *CombiningProcessor) Subscribed(id string) {
}

func (m *CombiningProcessor) Header(id string, header Header) error {
	header.general += "# Adjacent blocks with matching have been combined\n#\n"
	return m.Emitter.Header(header)
}

func (m *CombiningProcessor) buildAndEmit() error {
	//log.Printf("buildAndEmit: first=%s, last=%s, value='%s'", m.first.String(), m.last.String(), m.value)

	nets := make([]*net.IPNet, 0)
	IPNetFromFirstLast(&m.first, &m.last, &nets)
	for _, net := range nets {
		block := BlockCreate(net, &m.value)
		//log.Printf("buildAndEmit:   emit.net=%s, value='%s'", block.net.String(), *block.value)
		if err := m.Emit(block); err != nil {
			return err
		}
	}

	return nil
}

func (m *CombiningProcessor) Receive(id string, block *Block) error {
	//log.Printf("Receive: block.net=%s, block.value=%s", block.net.String(), *block.value)
	if m.value != *block.value || bytes.Compare(m.next, block.net.IP) != 0 {
		// There's a change in value or gap in ips, we can't comebine
		if len(m.value) > 0 {
			// We have a non-empty current value so we need to emit whatever
			// we've built up
			if err := m.buildAndEmit(); err != nil {
				return err
			}
		}
		// A new starting point and value for current, last will get updated
		// below
		m.first = block.net.IP
		m.value = *block.value
	}

	// Always update last
	m.last = *NetLast(block.net)
	m.next = *IPNext(&m.last)

	return nil
}

func (m *CombiningProcessor) Done(id string) error {
	return m.Emitter.Done()
}