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dumper.go
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dumper.go
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// Copyright (c) 2024 Karl Gaissmaier
// SPDX-License-Identifier: MIT
package bart
import (
"fmt"
"io"
"strconv"
"strings"
)
type nodeType byte
const (
nullNode nodeType = iota // empty node
fullNode // prefixes and children
leafNode // only prefixes
intermediateNode // only children
)
// ##################################################
// useful during development, debugging and testing
// ##################################################
// dumpString is just a wrapper for dump.
func (t *Table[V]) dumpString() string {
w := new(strings.Builder)
t.dump(w)
return w.String()
}
// dump the table structure and all the nodes to w.
//
// Output:
//
// [FULL] depth: 0 path: [] / 0
// indexs(#6): 1 66 128 133 266 383
// prefxs(#6): 0/0 8/6 0/7 10/7 10/8 127/8
// childs(#3): 10 127 192
//
// .[IMED] depth: 1 path: [10] / 8
// .childs(#1): 0
//
// ..[LEAF] depth: 2 path: [10.0] / 16
// ..indexs(#2): 256 257
// ..prefxs(#2): 0/8 1/8
//
// .[IMED] depth: 1 path: [127] / 8
// .childs(#1): 0
//
// ..[IMED] depth: 2 path: [127.0] / 16
// ..childs(#1): 0
//
// ...[LEAF] depth: 3 path: [127.0.0] / 24
// ...indexs(#1): 257
// ...prefxs(#1): 1/8
//
// ...
func (t *Table[V]) dump(w io.Writer) {
if !t.isInit() {
fmt.Fprint(w, "")
return
}
fmt.Fprint(w, "### IPv4:")
t.root4.dumpRec(w, zeroPath, 0, true)
fmt.Fprint(w, "### IPv6:")
t.root6.dumpRec(w, zeroPath, 0, false)
}
// dumpRec, rec-descent the trie.
func (n *node[V]) dumpRec(w io.Writer, path [16]byte, depth int, is4 bool) {
n.dump(w, path, depth, is4)
// make backing array, no heap allocs
addrBacking := make([]uint, maxNodeChildren)
// the node may have childs, the rec-descent monster starts
for i, addr := range n.allChildAddrs(addrBacking) {
octet := byte(addr)
child := n.children[i]
path[depth] = octet
child.dumpRec(w, path, depth+1, is4)
}
}
// dump the node to w.
func (n *node[V]) dump(w io.Writer, path [16]byte, depth int, is4 bool) {
bits := depth * strideLen
indent := strings.Repeat(".", depth)
// node type with depth and octet path and bits.
fmt.Fprintf(w, "\n%s[%s] depth: %d path: [%s] / %d\n",
indent, n.hasType(), depth, ipStridePath(path, depth, is4), bits)
if nPfxLen := len(n.prefixes); nPfxLen != 0 {
// make backing array, no heap allocs
idxBackingArray := [maxNodePrefixes]uint{}
allIndices := n.allStrideIndexes(idxBackingArray[:])
// print the baseIndices for this node.
fmt.Fprintf(w, "%sindexs(#%d): %v\n", indent, nPfxLen, allIndices)
// print the prefixes for this node
fmt.Fprintf(w, "%sprefxs(#%d):", indent, nPfxLen)
for _, idx := range allIndices {
octet, pfxLen := idxToPfx(idx)
fmt.Fprintf(w, " %s/%d", octetFmt(octet, is4), pfxLen)
}
fmt.Fprintln(w)
// print the values for this node
fmt.Fprintf(w, "%svalues(#%d):", indent, nPfxLen)
for _, val := range n.prefixes {
fmt.Fprintf(w, " %v", val)
}
fmt.Fprintln(w)
}
if childs := len(n.children); childs != 0 {
// print the childs for this node
fmt.Fprintf(w, "%schilds(#%d):", indent, childs)
addrBacking := make([]uint, maxNodeChildren)
for _, addr := range n.allChildAddrs(addrBacking) {
octet := byte(addr)
fmt.Fprintf(w, " %s", octetFmt(octet, is4))
}
fmt.Fprintln(w)
}
}
// octetFmt, different format strings for IPv4 and IPv6, decimal versus hex.
func octetFmt(octet byte, is4 bool) string {
if is4 {
return fmt.Sprintf("%d", octet)
}
return fmt.Sprintf("0x%02x", octet)
}
// ip stride path, different formats for IPv4 and IPv6, dotted decimal or hex.
//
// 127.0.0
// 2001:0d
func ipStridePath(path [16]byte, depth int, is4 bool) string {
buf := new(strings.Builder)
if is4 {
for i, b := range path[:depth] {
if i != 0 {
buf.WriteString(".")
}
buf.WriteString(strconv.Itoa(int(b)))
}
return buf.String()
}
for i, b := range path[:depth] {
if i != 0 && i%2 == 0 {
buf.WriteString(":")
}
buf.WriteString(fmt.Sprintf("%02x", b))
}
return buf.String()
}
// String implements Stringer for nodeType.
func (nt nodeType) String() string {
switch nt {
case nullNode:
return "NULL"
case fullNode:
return "FULL"
case leafNode:
return "LEAF"
case intermediateNode:
return "IMED"
}
panic("unreachable")
}
// hasType returns the nodeType.
func (n *node[V]) hasType() nodeType {
lenPefixes := len(n.prefixes)
lenChilds := len(n.children)
if lenPefixes == 0 && lenChilds != 0 {
return intermediateNode
}
if lenPefixes == 0 && lenChilds == 0 {
return nullNode
}
if lenPefixes != 0 && lenChilds == 0 {
return leafNode
}
if lenPefixes != 0 && lenChilds != 0 {
return fullNode
}
panic("unreachable")
}