| Server IP : 153.92.12.117 / Your IP : 216.73.217.32 Web Server : LiteSpeed System : Linux id-dci-web1986.main-hosting.eu 5.14.0-611.26.1.el9_7.x86_64 #1 SMP PREEMPT_DYNAMIC Thu Jan 29 05:24:47 EST 2026 x86_64 User : u686484674 ( 686484674) PHP Version : 8.0.30 Disable Function : system, exec, shell_exec, passthru, mysql_list_dbs, ini_alter, dl, symlink, link, chgrp, leak, popen, apache_child_terminate, virtual, mb_send_mail MySQL : OFF | cURL : ON | WGET : ON | Perl : OFF | Python : OFF | Sudo : OFF | Pkexec : OFF Directory : /proc/./self/root/opt/go/pkg/mod/github.com/hashicorp/go-immutable-radix@v1.3.1/ |
Upload File : |
package iradix
import (
"bytes"
)
// Iterator is used to iterate over a set of nodes
// in pre-order
type Iterator struct {
node *Node
stack []edges
}
// SeekPrefixWatch is used to seek the iterator to a given prefix
// and returns the watch channel of the finest granularity
func (i *Iterator) SeekPrefixWatch(prefix []byte) (watch <-chan struct{}) {
// Wipe the stack
i.stack = nil
n := i.node
watch = n.mutateCh
search := prefix
for {
// Check for key exhaustion
if len(search) == 0 {
i.node = n
return
}
// Look for an edge
_, n = n.getEdge(search[0])
if n == nil {
i.node = nil
return
}
// Update to the finest granularity as the search makes progress
watch = n.mutateCh
// Consume the search prefix
if bytes.HasPrefix(search, n.prefix) {
search = search[len(n.prefix):]
} else if bytes.HasPrefix(n.prefix, search) {
i.node = n
return
} else {
i.node = nil
return
}
}
}
// SeekPrefix is used to seek the iterator to a given prefix
func (i *Iterator) SeekPrefix(prefix []byte) {
i.SeekPrefixWatch(prefix)
}
func (i *Iterator) recurseMin(n *Node) *Node {
// Traverse to the minimum child
if n.leaf != nil {
return n
}
nEdges := len(n.edges)
if nEdges > 1 {
// Add all the other edges to the stack (the min node will be added as
// we recurse)
i.stack = append(i.stack, n.edges[1:])
}
if nEdges > 0 {
return i.recurseMin(n.edges[0].node)
}
// Shouldn't be possible
return nil
}
// SeekLowerBound is used to seek the iterator to the smallest key that is
// greater or equal to the given key. There is no watch variant as it's hard to
// predict based on the radix structure which node(s) changes might affect the
// result.
func (i *Iterator) SeekLowerBound(key []byte) {
// Wipe the stack. Unlike Prefix iteration, we need to build the stack as we
// go because we need only a subset of edges of many nodes in the path to the
// leaf with the lower bound. Note that the iterator will still recurse into
// children that we don't traverse on the way to the reverse lower bound as it
// walks the stack.
i.stack = []edges{}
// i.node starts off in the common case as pointing to the root node of the
// tree. By the time we return we have either found a lower bound and setup
// the stack to traverse all larger keys, or we have not and the stack and
// node should both be nil to prevent the iterator from assuming it is just
// iterating the whole tree from the root node. Either way this needs to end
// up as nil so just set it here.
n := i.node
i.node = nil
search := key
found := func(n *Node) {
i.stack = append(i.stack, edges{edge{node: n}})
}
findMin := func(n *Node) {
n = i.recurseMin(n)
if n != nil {
found(n)
return
}
}
for {
// Compare current prefix with the search key's same-length prefix.
var prefixCmp int
if len(n.prefix) < len(search) {
prefixCmp = bytes.Compare(n.prefix, search[0:len(n.prefix)])
} else {
prefixCmp = bytes.Compare(n.prefix, search)
}
if prefixCmp > 0 {
// Prefix is larger, that means the lower bound is greater than the search
// and from now on we need to follow the minimum path to the smallest
// leaf under this subtree.
findMin(n)
return
}
if prefixCmp < 0 {
// Prefix is smaller than search prefix, that means there is no lower
// bound
i.node = nil
return
}
// Prefix is equal, we are still heading for an exact match. If this is a
// leaf and an exact match we're done.
if n.leaf != nil && bytes.Equal(n.leaf.key, key) {
found(n)
return
}
// Consume the search prefix if the current node has one. Note that this is
// safe because if n.prefix is longer than the search slice prefixCmp would
// have been > 0 above and the method would have already returned.
search = search[len(n.prefix):]
if len(search) == 0 {
// We've exhausted the search key, but the current node is not an exact
// match or not a leaf. That means that the leaf value if it exists, and
// all child nodes must be strictly greater, the smallest key in this
// subtree must be the lower bound.
findMin(n)
return
}
// Otherwise, take the lower bound next edge.
idx, lbNode := n.getLowerBoundEdge(search[0])
if lbNode == nil {
return
}
// Create stack edges for the all strictly higher edges in this node.
if idx+1 < len(n.edges) {
i.stack = append(i.stack, n.edges[idx+1:])
}
// Recurse
n = lbNode
}
}
// Next returns the next node in order
func (i *Iterator) Next() ([]byte, interface{}, bool) {
// Initialize our stack if needed
if i.stack == nil && i.node != nil {
i.stack = []edges{
{
edge{node: i.node},
},
}
}
for len(i.stack) > 0 {
// Inspect the last element of the stack
n := len(i.stack)
last := i.stack[n-1]
elem := last[0].node
// Update the stack
if len(last) > 1 {
i.stack[n-1] = last[1:]
} else {
i.stack = i.stack[:n-1]
}
// Push the edges onto the frontier
if len(elem.edges) > 0 {
i.stack = append(i.stack, elem.edges)
}
// Return the leaf values if any
if elem.leaf != nil {
return elem.leaf.key, elem.leaf.val, true
}
}
return nil, nil, false
}