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package maxminddb
import "net"
// Internal structure used to keep track of nodes we still need to visit.
type netNode struct {
ip net.IP
bit uint
pointer uint
}
// Networks represents a set of subnets that we are iterating over.
type Networks struct {
reader *Reader
nodes []netNode // Nodes we still have to visit.
lastNode netNode
err error
}
// Networks returns an iterator that can be used to traverse all networks in
// the database.
//
// Please note that a MaxMind DB may map IPv4 networks into several locations
// in in an IPv6 database. This iterator will iterate over all of these
// locations separately.
func (r *Reader) Networks() *Networks {
s := 4
if r.Metadata.IPVersion == 6 {
s = 16
}
return &Networks{
reader: r,
nodes: []netNode{
{
ip: make(net.IP, s),
},
},
}
}
// Next prepares the next network for reading with the Network method. It
// returns true if there is another network to be processed and false if there
// are no more networks or if there is an error.
func (n *Networks) Next() bool {
for len(n.nodes) > 0 {
node := n.nodes[len(n.nodes)-1]
n.nodes = n.nodes[:len(n.nodes)-1]
for {
if node.pointer < n.reader.Metadata.NodeCount {
ipRight := make(net.IP, len(node.ip))
copy(ipRight, node.ip)
if len(ipRight) <= int(node.bit>>3) {
n.err = newInvalidDatabaseError(
"invalid search tree at %v/%v", ipRight, node.bit)
return false
}
ipRight[node.bit>>3] |= 1 << (7 - (node.bit % 8))
rightPointer, err := n.reader.readNode(node.pointer, 1)
if err != nil {
n.err = err
return false
}
node.bit++
n.nodes = append(n.nodes, netNode{
pointer: rightPointer,
ip: ipRight,
bit: node.bit,
})
node.pointer, err = n.reader.readNode(node.pointer, 0)
if err != nil {
n.err = err
return false
}
} else if node.pointer > n.reader.Metadata.NodeCount {
n.lastNode = node
return true
} else {
break
}
}
}
return false
}
// Network returns the current network or an error if there is a problem
// decoding the data for the network. It takes a pointer to a result value to
// decode the network's data into.
func (n *Networks) Network(result interface{}) (*net.IPNet, error) {
if err := n.reader.retrieveData(n.lastNode.pointer, result); err != nil {
return nil, err
}
return &net.IPNet{
IP: n.lastNode.ip,
Mask: net.CIDRMask(int(n.lastNode.bit), len(n.lastNode.ip)*8),
}, nil
}
// Err returns an error, if any, that was encountered during iteration.
func (n *Networks) Err() error {
return n.err
}