mirror of
https://github.com/rclone/rclone.git
synced 2024-12-11 17:51:12 +01:00
252 lines
7.3 KiB
Go
252 lines
7.3 KiB
Go
// Copyright 2014 The Go Authors. All rights reserved.
|
|
// Use of this source code is governed by a BSD-style
|
|
// license that can be found in the LICENSE file.
|
|
|
|
package triegen
|
|
|
|
import (
|
|
"bytes"
|
|
"fmt"
|
|
"io"
|
|
"strings"
|
|
"text/template"
|
|
)
|
|
|
|
// print writes all the data structures as well as the code necessary to use the
|
|
// trie to w.
|
|
func (b *builder) print(w io.Writer) error {
|
|
b.Stats.NValueEntries = len(b.ValueBlocks) * blockSize
|
|
b.Stats.NValueBytes = len(b.ValueBlocks) * blockSize * b.ValueSize
|
|
b.Stats.NIndexEntries = len(b.IndexBlocks) * blockSize
|
|
b.Stats.NIndexBytes = len(b.IndexBlocks) * blockSize * b.IndexSize
|
|
b.Stats.NHandleBytes = len(b.Trie) * 2 * b.IndexSize
|
|
|
|
// If we only have one root trie, all starter blocks are at position 0 and
|
|
// we can access the arrays directly.
|
|
if len(b.Trie) == 1 {
|
|
// At this point we cannot refer to the generated tables directly.
|
|
b.ASCIIBlock = b.Name + "Values"
|
|
b.StarterBlock = b.Name + "Index"
|
|
} else {
|
|
// Otherwise we need to have explicit starter indexes in the trie
|
|
// structure.
|
|
b.ASCIIBlock = "t.ascii"
|
|
b.StarterBlock = "t.utf8Start"
|
|
}
|
|
|
|
b.SourceType = "[]byte"
|
|
if err := lookupGen.Execute(w, b); err != nil {
|
|
return err
|
|
}
|
|
|
|
b.SourceType = "string"
|
|
if err := lookupGen.Execute(w, b); err != nil {
|
|
return err
|
|
}
|
|
|
|
if err := trieGen.Execute(w, b); err != nil {
|
|
return err
|
|
}
|
|
|
|
for _, c := range b.Compactions {
|
|
if err := c.c.Print(w); err != nil {
|
|
return err
|
|
}
|
|
}
|
|
|
|
return nil
|
|
}
|
|
|
|
func printValues(n int, values []uint64) string {
|
|
w := &bytes.Buffer{}
|
|
boff := n * blockSize
|
|
fmt.Fprintf(w, "\t// Block %#x, offset %#x", n, boff)
|
|
var newline bool
|
|
for i, v := range values {
|
|
if i%6 == 0 {
|
|
newline = true
|
|
}
|
|
if v != 0 {
|
|
if newline {
|
|
fmt.Fprintf(w, "\n")
|
|
newline = false
|
|
}
|
|
fmt.Fprintf(w, "\t%#02x:%#04x, ", boff+i, v)
|
|
}
|
|
}
|
|
return w.String()
|
|
}
|
|
|
|
func printIndex(b *builder, nr int, n *node) string {
|
|
w := &bytes.Buffer{}
|
|
boff := nr * blockSize
|
|
fmt.Fprintf(w, "\t// Block %#x, offset %#x", nr, boff)
|
|
var newline bool
|
|
for i, c := range n.children {
|
|
if i%8 == 0 {
|
|
newline = true
|
|
}
|
|
if c != nil {
|
|
v := b.Compactions[c.index.compaction].Offset + uint32(c.index.index)
|
|
if v != 0 {
|
|
if newline {
|
|
fmt.Fprintf(w, "\n")
|
|
newline = false
|
|
}
|
|
fmt.Fprintf(w, "\t%#02x:%#02x, ", boff+i, v)
|
|
}
|
|
}
|
|
}
|
|
return w.String()
|
|
}
|
|
|
|
var (
|
|
trieGen = template.Must(template.New("trie").Funcs(template.FuncMap{
|
|
"printValues": printValues,
|
|
"printIndex": printIndex,
|
|
"title": strings.Title,
|
|
"dec": func(x int) int { return x - 1 },
|
|
"psize": func(n int) string {
|
|
return fmt.Sprintf("%d bytes (%.2f KiB)", n, float64(n)/1024)
|
|
},
|
|
}).Parse(trieTemplate))
|
|
lookupGen = template.Must(template.New("lookup").Parse(lookupTemplate))
|
|
)
|
|
|
|
// TODO: consider the return type of lookup. It could be uint64, even if the
|
|
// internal value type is smaller. We will have to verify this with the
|
|
// performance of unicode/norm, which is very sensitive to such changes.
|
|
const trieTemplate = `{{$b := .}}{{$multi := gt (len .Trie) 1}}
|
|
// {{.Name}}Trie. Total size: {{psize .Size}}. Checksum: {{printf "%08x" .Checksum}}.
|
|
type {{.Name}}Trie struct { {{if $multi}}
|
|
ascii []{{.ValueType}} // index for ASCII bytes
|
|
utf8Start []{{.IndexType}} // index for UTF-8 bytes >= 0xC0
|
|
{{end}}}
|
|
|
|
func new{{title .Name}}Trie(i int) *{{.Name}}Trie { {{if $multi}}
|
|
h := {{.Name}}TrieHandles[i]
|
|
return &{{.Name}}Trie{ {{.Name}}Values[uint32(h.ascii)<<6:], {{.Name}}Index[uint32(h.multi)<<6:] }
|
|
}
|
|
|
|
type {{.Name}}TrieHandle struct {
|
|
ascii, multi {{.IndexType}}
|
|
}
|
|
|
|
// {{.Name}}TrieHandles: {{len .Trie}} handles, {{.Stats.NHandleBytes}} bytes
|
|
var {{.Name}}TrieHandles = [{{len .Trie}}]{{.Name}}TrieHandle{
|
|
{{range .Trie}} { {{.ASCIIIndex}}, {{.StarterIndex}} }, // {{printf "%08x" .Checksum}}: {{.Name}}
|
|
{{end}}}{{else}}
|
|
return &{{.Name}}Trie{}
|
|
}
|
|
{{end}}
|
|
// lookupValue determines the type of block n and looks up the value for b.
|
|
func (t *{{.Name}}Trie) lookupValue(n uint32, b byte) {{.ValueType}}{{$last := dec (len .Compactions)}} {
|
|
switch { {{range $i, $c := .Compactions}}
|
|
{{if eq $i $last}}default{{else}}case n < {{$c.Cutoff}}{{end}}:{{if ne $i 0}}
|
|
n -= {{$c.Offset}}{{end}}
|
|
return {{print $b.ValueType}}({{$c.Handler}}){{end}}
|
|
}
|
|
}
|
|
|
|
// {{.Name}}Values: {{len .ValueBlocks}} blocks, {{.Stats.NValueEntries}} entries, {{.Stats.NValueBytes}} bytes
|
|
// The third block is the zero block.
|
|
var {{.Name}}Values = [{{.Stats.NValueEntries}}]{{.ValueType}} {
|
|
{{range $i, $v := .ValueBlocks}}{{printValues $i $v}}
|
|
{{end}}}
|
|
|
|
// {{.Name}}Index: {{len .IndexBlocks}} blocks, {{.Stats.NIndexEntries}} entries, {{.Stats.NIndexBytes}} bytes
|
|
// Block 0 is the zero block.
|
|
var {{.Name}}Index = [{{.Stats.NIndexEntries}}]{{.IndexType}} {
|
|
{{range $i, $v := .IndexBlocks}}{{printIndex $b $i $v}}
|
|
{{end}}}
|
|
`
|
|
|
|
// TODO: consider allowing zero-length strings after evaluating performance with
|
|
// unicode/norm.
|
|
const lookupTemplate = `
|
|
// lookup{{if eq .SourceType "string"}}String{{end}} returns the trie value for the first UTF-8 encoding in s and
|
|
// the width in bytes of this encoding. The size will be 0 if s does not
|
|
// hold enough bytes to complete the encoding. len(s) must be greater than 0.
|
|
func (t *{{.Name}}Trie) lookup{{if eq .SourceType "string"}}String{{end}}(s {{.SourceType}}) (v {{.ValueType}}, sz int) {
|
|
c0 := s[0]
|
|
switch {
|
|
case c0 < 0x80: // is ASCII
|
|
return {{.ASCIIBlock}}[c0], 1
|
|
case c0 < 0xC2:
|
|
return 0, 1 // Illegal UTF-8: not a starter, not ASCII.
|
|
case c0 < 0xE0: // 2-byte UTF-8
|
|
if len(s) < 2 {
|
|
return 0, 0
|
|
}
|
|
i := {{.StarterBlock}}[c0]
|
|
c1 := s[1]
|
|
if c1 < 0x80 || 0xC0 <= c1 {
|
|
return 0, 1 // Illegal UTF-8: not a continuation byte.
|
|
}
|
|
return t.lookupValue(uint32(i), c1), 2
|
|
case c0 < 0xF0: // 3-byte UTF-8
|
|
if len(s) < 3 {
|
|
return 0, 0
|
|
}
|
|
i := {{.StarterBlock}}[c0]
|
|
c1 := s[1]
|
|
if c1 < 0x80 || 0xC0 <= c1 {
|
|
return 0, 1 // Illegal UTF-8: not a continuation byte.
|
|
}
|
|
o := uint32(i)<<6 + uint32(c1)
|
|
i = {{.Name}}Index[o]
|
|
c2 := s[2]
|
|
if c2 < 0x80 || 0xC0 <= c2 {
|
|
return 0, 2 // Illegal UTF-8: not a continuation byte.
|
|
}
|
|
return t.lookupValue(uint32(i), c2), 3
|
|
case c0 < 0xF8: // 4-byte UTF-8
|
|
if len(s) < 4 {
|
|
return 0, 0
|
|
}
|
|
i := {{.StarterBlock}}[c0]
|
|
c1 := s[1]
|
|
if c1 < 0x80 || 0xC0 <= c1 {
|
|
return 0, 1 // Illegal UTF-8: not a continuation byte.
|
|
}
|
|
o := uint32(i)<<6 + uint32(c1)
|
|
i = {{.Name}}Index[o]
|
|
c2 := s[2]
|
|
if c2 < 0x80 || 0xC0 <= c2 {
|
|
return 0, 2 // Illegal UTF-8: not a continuation byte.
|
|
}
|
|
o = uint32(i)<<6 + uint32(c2)
|
|
i = {{.Name}}Index[o]
|
|
c3 := s[3]
|
|
if c3 < 0x80 || 0xC0 <= c3 {
|
|
return 0, 3 // Illegal UTF-8: not a continuation byte.
|
|
}
|
|
return t.lookupValue(uint32(i), c3), 4
|
|
}
|
|
// Illegal rune
|
|
return 0, 1
|
|
}
|
|
|
|
// lookup{{if eq .SourceType "string"}}String{{end}}Unsafe returns the trie value for the first UTF-8 encoding in s.
|
|
// s must start with a full and valid UTF-8 encoded rune.
|
|
func (t *{{.Name}}Trie) lookup{{if eq .SourceType "string"}}String{{end}}Unsafe(s {{.SourceType}}) {{.ValueType}} {
|
|
c0 := s[0]
|
|
if c0 < 0x80 { // is ASCII
|
|
return {{.ASCIIBlock}}[c0]
|
|
}
|
|
i := {{.StarterBlock}}[c0]
|
|
if c0 < 0xE0 { // 2-byte UTF-8
|
|
return t.lookupValue(uint32(i), s[1])
|
|
}
|
|
i = {{.Name}}Index[uint32(i)<<6+uint32(s[1])]
|
|
if c0 < 0xF0 { // 3-byte UTF-8
|
|
return t.lookupValue(uint32(i), s[2])
|
|
}
|
|
i = {{.Name}}Index[uint32(i)<<6+uint32(s[2])]
|
|
if c0 < 0xF8 { // 4-byte UTF-8
|
|
return t.lookupValue(uint32(i), s[3])
|
|
}
|
|
return 0
|
|
}
|
|
`
|