gotosocial/vendor/modernc.org/strutil/strutil.go

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// Copyright (c) 2014 The sortutil 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 strutil collects utils supplemental to the standard strings package.
package strutil // import "modernc.org/strutil"
import (
"bytes"
"encoding/base32"
"encoding/base64"
"fmt"
"io"
"os"
"path/filepath"
"reflect"
"runtime"
"sort"
"strconv"
"strings"
"sync"
)
// Base32ExtDecode decodes base32 extended (RFC 4648) text to binary data.
func Base32ExtDecode(text []byte) (data []byte, err error) {
n := base32.HexEncoding.DecodedLen(len(text))
data = make([]byte, n)
decoder := base32.NewDecoder(base32.HexEncoding, bytes.NewBuffer(text))
if n, err = decoder.Read(data); err != nil {
n = 0
}
data = data[:n]
return
}
// Base32ExtEncode encodes binary data to base32 extended (RFC 4648) encoded text.
func Base32ExtEncode(data []byte) (text []byte) {
n := base32.HexEncoding.EncodedLen(len(data))
buf := bytes.NewBuffer(make([]byte, 0, n))
encoder := base32.NewEncoder(base32.HexEncoding, buf)
encoder.Write(data)
encoder.Close()
if buf.Len() != n {
panic("internal error")
}
return buf.Bytes()
}
// Base64Decode decodes base64 text to binary data.
func Base64Decode(text []byte) (data []byte, err error) {
n := base64.StdEncoding.DecodedLen(len(text))
data = make([]byte, n)
decoder := base64.NewDecoder(base64.StdEncoding, bytes.NewBuffer(text))
if n, err = decoder.Read(data); err != nil {
n = 0
}
data = data[:n]
return
}
// Base64Encode encodes binary data to base64 encoded text.
func Base64Encode(data []byte) (text []byte) {
n := base64.StdEncoding.EncodedLen(len(data))
buf := bytes.NewBuffer(make([]byte, 0, n))
encoder := base64.NewEncoder(base64.StdEncoding, buf)
encoder.Write(data)
encoder.Close()
if buf.Len() != n {
panic("internal error")
}
return buf.Bytes()
}
// Formatter is an io.Writer extended by a fmt.Printf like function Format
type Formatter interface {
io.Writer
Format(format string, args ...interface{}) (n int, errno error)
}
type indentFormatter struct {
io.Writer
indent []byte
indentLevel int
state int
}
const (
st0 = iota
stBOL
stPERC
stBOLPERC
)
// IndentFormatter returns a new Formatter which interprets %i and %u in the
// Format() format string as indent and undent commands. The commands can
// nest. The Formatter writes to io.Writer 'w' and inserts one 'indent'
// string per current indent level value.
// Behaviour of commands reaching negative indent levels is undefined.
// IndentFormatter(os.Stdout, "\t").Format("abc%d%%e%i\nx\ny\n%uz\n", 3)
// output:
// abc3%e
// x
// y
// z
// The Go quoted string literal form of the above is:
// "abc%%e\n\tx\n\tx\nz\n"
// The commands can be scattered between separate invocations of Format(),
// i.e. the formatter keeps track of the indent level and knows if it is
// positioned on start of a line and should emit indentation(s).
// The same output as above can be produced by e.g.:
// f := IndentFormatter(os.Stdout, " ")
// f.Format("abc%d%%e%i\nx\n", 3)
// f.Format("y\n%uz\n")
func IndentFormatter(w io.Writer, indent string) Formatter {
return &indentFormatter{w, []byte(indent), 0, stBOL}
}
func (f *indentFormatter) format(flat bool, format string, args ...interface{}) (n int, errno error) {
buf := []byte{}
for i := 0; i < len(format); i++ {
c := format[i]
switch f.state {
case st0:
switch c {
case '\n':
cc := c
if flat && f.indentLevel != 0 {
cc = ' '
}
buf = append(buf, cc)
f.state = stBOL
case '%':
f.state = stPERC
default:
buf = append(buf, c)
}
case stBOL:
switch c {
case '\n':
cc := c
if flat && f.indentLevel != 0 {
cc = ' '
}
buf = append(buf, cc)
case '%':
f.state = stBOLPERC
default:
if !flat {
for i := 0; i < f.indentLevel; i++ {
buf = append(buf, f.indent...)
}
}
buf = append(buf, c)
f.state = st0
}
case stBOLPERC:
switch c {
case 'i':
f.indentLevel++
f.state = stBOL
case 'u':
f.indentLevel--
f.state = stBOL
default:
if !flat {
for i := 0; i < f.indentLevel; i++ {
buf = append(buf, f.indent...)
}
}
buf = append(buf, '%', c)
f.state = st0
}
case stPERC:
switch c {
case 'i':
f.indentLevel++
f.state = st0
case 'u':
f.indentLevel--
f.state = st0
default:
buf = append(buf, '%', c)
f.state = st0
}
default:
panic("unexpected state")
}
}
switch f.state {
case stPERC, stBOLPERC:
buf = append(buf, '%')
}
return f.Write([]byte(fmt.Sprintf(string(buf), args...)))
}
func (f *indentFormatter) Format(format string, args ...interface{}) (n int, errno error) {
return f.format(false, format, args...)
}
type flatFormatter indentFormatter
// FlatFormatter returns a newly created Formatter with the same functionality as the one returned
// by IndentFormatter except it allows a newline in the 'format' string argument of Format
// to pass through iff indent level is currently zero.
//
// If indent level is non-zero then such new lines are changed to a space character.
// There is no indent string, the %i and %u format verbs are used solely to determine the indent level.
//
// The FlatFormatter is intended for flattening of normally nested structure textual representation to
// a one top level structure per line form.
// FlatFormatter(os.Stdout, " ").Format("abc%d%%e%i\nx\ny\n%uz\n", 3)
// output in the form of a Go quoted string literal:
// "abc3%%e x y z\n"
func FlatFormatter(w io.Writer) Formatter {
return (*flatFormatter)(IndentFormatter(w, "").(*indentFormatter))
}
func (f *flatFormatter) Format(format string, args ...interface{}) (n int, errno error) {
return (*indentFormatter)(f).format(true, format, args...)
}
// Pool handles aligning of strings having equal values to the same string instance.
// Intended use is to conserve some memory e.g. where a large number of identically valued strings
// with non identical backing arrays may exists in several semantically distinct instances of some structs.
// Pool is *not* concurrent access safe. It doesn't handle common prefix/suffix aligning,
// e.g. having s1 == "abc" and s2 == "bc", s2 is not automatically aligned as s1[1:].
type Pool struct {
pool map[string]string
}
// NewPool returns a newly created Pool.
func NewPool() *Pool {
return &Pool{map[string]string{}}
}
// Align returns a string with the same value as its argument. It guarantees that
// all aligned strings share a single instance in memory.
func (p *Pool) Align(s string) string {
if a, ok := p.pool[s]; ok {
return a
}
s = StrPack(s)
p.pool[s] = s
return s
}
// Count returns the number of items in the pool.
func (p *Pool) Count() int {
return len(p.pool)
}
// GoPool is a concurrent access safe version of Pool.
type GoPool struct {
pool map[string]string
rwm *sync.RWMutex
}
// NewGoPool returns a newly created GoPool.
func NewGoPool() (p *GoPool) {
return &GoPool{map[string]string{}, &sync.RWMutex{}}
}
// Align returns a string with the same value as its argument. It guarantees that
// all aligned strings share a single instance in memory.
func (p *GoPool) Align(s string) (y string) {
if s != "" {
p.rwm.RLock() // R++
if a, ok := p.pool[s]; ok { // found
p.rwm.RUnlock() // R--
return a
}
p.rwm.RUnlock() // R--
// not found but with a race condition, retry within a write lock
p.rwm.Lock() // W++
defer p.rwm.Unlock() // W--
if a, ok := p.pool[s]; ok { // done in a race
return a
}
// we won
s = StrPack(s)
p.pool[s] = s
return s
}
return
}
// Count returns the number of items in the pool.
func (p *GoPool) Count() int {
return len(p.pool)
}
// Dict is a string <-> id bijection. Dict is *not* concurrent access safe for assigning new ids
// to strings not yet contained in the bijection.
// Id for an empty string is guaranteed to be 0,
// thus Id for any non empty string is guaranteed to be non zero.
type Dict struct {
si map[string]int
is []string
}
// NewDict returns a newly created Dict.
func NewDict() (d *Dict) {
d = &Dict{map[string]int{}, []string{}}
d.Id("")
return
}
// Count returns the number of items in the dict.
func (d *Dict) Count() int {
return len(d.is)
}
// Id maps string s to its numeric identificator.
func (d *Dict) Id(s string) (y int) {
if y, ok := d.si[s]; ok {
return y
}
s = StrPack(s)
y = len(d.is)
d.si[s] = y
d.is = append(d.is, s)
return
}
// S maps an id to its string value and ok == true. Id values not contained in the bijection
// return "", false.
func (d *Dict) S(id int) (s string, ok bool) {
if id >= len(d.is) {
return "", false
}
return d.is[id], true
}
// GoDict is a concurrent access safe version of Dict.
type GoDict struct {
si map[string]int
is []string
rwm *sync.RWMutex
}
// NewGoDict returns a newly created GoDict.
func NewGoDict() (d *GoDict) {
d = &GoDict{map[string]int{}, []string{}, &sync.RWMutex{}}
d.Id("")
return
}
// Count returns the number of items in the dict.
func (d *GoDict) Count() int {
return len(d.is)
}
// Id maps string s to its numeric identificator. The implementation honors getting
// an existing id at the cost of assigning a new one.
func (d *GoDict) Id(s string) (y int) {
d.rwm.RLock() // R++
if y, ok := d.si[s]; ok { // found
d.rwm.RUnlock() // R--
return y
}
d.rwm.RUnlock() // R--
// not found but with a race condition
d.rwm.Lock() // W++ recheck with write lock
defer d.rwm.Unlock() // W--
if y, ok := d.si[s]; ok { // some other goroutine won already
return y
}
// a race free not found state => insert the string
s = StrPack(s)
y = len(d.is)
d.si[s] = y
d.is = append(d.is, s)
return
}
// S maps an id to its string value and ok == true. Id values not contained in the bijection
// return "", false.
func (d *GoDict) S(id int) (s string, ok bool) {
d.rwm.RLock() // R++
defer d.rwm.RUnlock() // R--
if id >= len(d.is) {
return "", false
}
return d.is[id], true
}
// StrPack returns a new instance of s which is tightly packed in memory.
// It is intended for avoiding the situation where having a live reference
// to a string slice over an unreferenced biger underlying string keeps the biger one
// in memory anyway - it can't be GCed.
func StrPack(s string) string {
return string([]byte(s)) // T(U(T)) intentional.
}
// JoinFields returns strings in flds joined by sep. Flds may contain arbitrary
// bytes, including the sep as they are safely escaped. JoinFields panics if
// sep is the backslash character or if len(sep) != 1.
func JoinFields(flds []string, sep string) string {
if len(sep) != 1 || sep == "\\" {
panic("invalid separator")
}
a := make([]string, len(flds))
for i, v := range flds {
v = strings.Replace(v, "\\", "\\0", -1)
a[i] = strings.Replace(v, sep, "\\1", -1)
}
return strings.Join(a, sep)
}
// SplitFields splits s, which must be produced by JoinFields using the same
// sep, into flds. SplitFields panics if sep is the backslash character or if
// len(sep) != 1.
func SplitFields(s, sep string) (flds []string) {
if len(sep) != 1 || sep == "\\" {
panic("invalid separator")
}
a := strings.Split(s, sep)
r := make([]string, len(a))
for i, v := range a {
v = strings.Replace(v, "\\1", sep, -1)
r[i] = strings.Replace(v, "\\0", "\\", -1)
}
return r
}
// PrettyPrintHooks allow to customize the result of PrettyPrint for types
// listed in the map value.
type PrettyPrintHooks map[reflect.Type]func(f Formatter, v interface{}, prefix, suffix string)
// PrettyString returns the output of PrettyPrint as a string.
func PrettyString(v interface{}, prefix, suffix string, hooks PrettyPrintHooks) string {
var b bytes.Buffer
PrettyPrint(&b, v, prefix, suffix, hooks)
return b.String()
}
// PrettyPrint pretty prints v to w. Zero values and unexported struct fields
// are omitted.
//
// Force printing of zero values of struct fields by including in the field tag
// PrettyPrint:"zero".
//
// Enable using a String method, if any, of a struct field type by including in
// the field tag PrettyPrint:"stringer".
//
// The tags can be combined as in PrettyPrint:"zero,stringer". The order is not
// important, so PrettyPrint:stringer,zero has the same effect.
//
// A hook attached to the field type has priority over the struct field tag
// described above.
func PrettyPrint(w io.Writer, v interface{}, prefix, suffix string, hooks PrettyPrintHooks) {
if v == nil {
return
}
f := IndentFormatter(w, "· ")
defer func() {
if e := recover(); e != nil {
f.Format("\npanic: %v", e)
}
}()
prettyPrint(nil, f, prefix, suffix, v, hooks, false, false)
}
func prettyPrint(protect map[interface{}]struct{}, sf Formatter, prefix, suffix string, v interface{}, hooks PrettyPrintHooks, zero, stringer bool) {
if v == nil {
return
}
rt := reflect.TypeOf(v)
if handler := hooks[rt]; handler != nil {
handler(sf, v, prefix, suffix)
return
}
rv := reflect.ValueOf(v)
if stringer {
if _, ok := v.(fmt.Stringer); ok {
sf.Format("%s%s", prefix, v)
sf.Format(suffix)
return
}
}
switch rt.Kind() {
case reflect.Slice:
if rv.Len() == 0 && !zero {
return
}
sf.Format("%s[]%T{ // len %d%i\n", prefix, rv.Index(0).Interface(), rv.Len())
for i := 0; i < rv.Len(); i++ {
prettyPrint(protect, sf, fmt.Sprintf("%d: ", i), ",\n", rv.Index(i).Interface(), hooks, false, false)
}
suffix = strings.Replace(suffix, "%", "%%", -1)
sf.Format("%u}" + suffix)
case reflect.Array:
if reflect.Zero(rt).Interface() == rv.Interface() && !zero {
return
}
sf.Format("%s[%d]%T{%i\n", prefix, rv.Len(), rv.Index(0).Interface())
for i := 0; i < rv.Len(); i++ {
prettyPrint(protect, sf, fmt.Sprintf("%d: ", i), ",\n", rv.Index(i).Interface(), hooks, false, false)
}
suffix = strings.Replace(suffix, "%", "%%", -1)
sf.Format("%u}" + suffix)
case reflect.Struct:
if rt.NumField() == 0 {
return
}
if reflect.DeepEqual(reflect.Zero(rt).Interface(), rv.Interface()) && !zero {
return
}
sf.Format("%s%T{%i\n", prefix, v)
for i := 0; i < rt.NumField(); i++ {
f := rv.Field(i)
if !f.CanInterface() {
continue
}
var stringer, zero bool
ft := rt.Field(i)
if tag, ok := ft.Tag.Lookup("PrettyPrint"); ok {
a := strings.Split(tag, ",")
for _, v := range a {
switch strings.TrimSpace(v) {
case "stringer":
stringer = true
case "zero":
zero = true
}
}
}
prettyPrint(protect, sf, fmt.Sprintf("%s: ", rt.Field(i).Name), ",\n", f.Interface(), hooks, zero, stringer)
}
suffix = strings.Replace(suffix, "%", "%%", -1)
sf.Format("%u}" + suffix)
case reflect.Ptr:
if rv.IsNil() && !zero {
return
}
rvi := rv.Interface()
if _, ok := protect[rvi]; ok {
suffix = strings.Replace(suffix, "%", "%%", -1)
sf.Format("%s&%T{ /* recursive/repetitive pointee not shown */ }"+suffix, prefix, rv.Elem().Interface())
return
}
if protect == nil {
protect = map[interface{}]struct{}{}
}
protect[rvi] = struct{}{}
prettyPrint(protect, sf, prefix+"&", suffix, rv.Elem().Interface(), hooks, false, false)
case reflect.Int, reflect.Int16, reflect.Int32, reflect.Int64, reflect.Int8:
if v := rv.Int(); v != 0 || zero {
suffix = strings.Replace(suffix, "%", "%%", -1)
sf.Format("%s%v"+suffix, prefix, v)
}
case reflect.Uint, reflect.Uint16, reflect.Uint32, reflect.Uint64, reflect.Uint8:
if v := rv.Uint(); v != 0 || zero {
suffix = strings.Replace(suffix, "%", "%%", -1)
sf.Format("%s%v"+suffix, prefix, v)
}
case reflect.Float32, reflect.Float64:
if v := rv.Float(); v != 0 || zero {
suffix = strings.Replace(suffix, "%", "%%", -1)
sf.Format("%s%v"+suffix, prefix, v)
}
case reflect.Complex64, reflect.Complex128:
if v := rv.Complex(); v != 0 || zero {
suffix = strings.Replace(suffix, "%", "%%", -1)
sf.Format("%s%v"+suffix, prefix, v)
}
case reflect.Uintptr:
if v := rv.Uint(); v != 0 || zero {
suffix = strings.Replace(suffix, "%", "%%", -1)
sf.Format("%s%v"+suffix, prefix, v)
}
case reflect.UnsafePointer:
s := fmt.Sprintf("%p", rv.Interface())
if s == "0x0" && !zero {
return
}
suffix = strings.Replace(suffix, "%", "%%", -1)
sf.Format("%s%s"+suffix, prefix, s)
case reflect.Bool:
if v := rv.Bool(); v || zero {
suffix = strings.Replace(suffix, "%", "%%", -1)
sf.Format("%s%v"+suffix, prefix, rv.Bool())
}
case reflect.String:
s := rv.Interface().(string)
if s == "" && !zero {
return
}
suffix = strings.Replace(suffix, "%", "%%", -1)
sf.Format("%s%q"+suffix, prefix, s)
case reflect.Chan:
if reflect.Zero(rt).Interface() == rv.Interface() && !zero {
return
}
c := rv.Cap()
s := ""
if c != 0 {
s = fmt.Sprintf("// capacity: %d", c)
}
suffix = strings.Replace(suffix, "%", "%%", -1)
sf.Format("%s%s %s%s"+suffix, prefix, rt.ChanDir(), rt.Elem().Name(), s)
case reflect.Func:
if rv.IsNil() && !zero {
return
}
var in, out []string
for i := 0; i < rt.NumIn(); i++ {
x := reflect.Zero(rt.In(i))
in = append(in, fmt.Sprintf("%T", x.Interface()))
}
if rt.IsVariadic() {
i := len(in) - 1
in[i] = "..." + in[i][2:]
}
for i := 0; i < rt.NumOut(); i++ {
out = append(out, rt.Out(i).Name())
}
s := "(" + strings.Join(in, ", ") + ")"
t := strings.Join(out, ", ")
if len(out) > 1 {
t = "(" + t + ")"
}
if t != "" {
t = " " + t
}
suffix = strings.Replace(suffix, "%", "%%", -1)
sf.Format("%sfunc%s%s { ... }"+suffix, prefix, s, t)
case reflect.Map:
keys := rv.MapKeys()
if len(keys) == 0 && !zero {
return
}
var buf bytes.Buffer
nf := IndentFormatter(&buf, "· ")
var skeys []string
for i, k := range keys {
prettyPrint(protect, nf, "", "", k.Interface(), hooks, false, false)
skeys = append(skeys, fmt.Sprintf("%s%10d", buf.Bytes(), i))
buf.Reset()
}
sort.Strings(skeys)
sf.Format("%s%T{%i\n", prefix, v)
for _, k := range skeys {
si := strings.TrimSpace(k[len(k)-10:])
k = k[:len(k)-10]
n, _ := strconv.ParseUint(si, 10, 64)
mv := rv.MapIndex(keys[n])
prettyPrint(protect, sf, fmt.Sprintf("%s: ", k), ",\n", mv.Interface(), hooks, false, false)
}
suffix = strings.Replace(suffix, "%", "%%", -1)
sf.Format("%u}" + suffix)
}
}
// Gopath returns the value of the $GOPATH environment variable or its default
// value if not set.
func Gopath() string {
if r := os.Getenv("GOPATH"); r != "" {
return r
}
// go1.8: https://github.com/golang/go/blob/74628a8b9f102bddd5078ee426efe0fd57033115/doc/code.html#L122
switch runtime.GOOS {
case "plan9":
return os.Getenv("home")
case "windows":
return filepath.Join(os.Getenv("USERPROFILE"), "go")
default:
return filepath.Join(os.Getenv("HOME"), "go")
}
}
// Homepath returns the user's home directory path.
func Homepath() string {
// go1.8: https://github.com/golang/go/blob/74628a8b9f102bddd5078ee426efe0fd57033115/doc/code.html#L122
switch runtime.GOOS {
case "plan9":
return os.Getenv("home")
case "windows":
return os.Getenv("USERPROFILE")
default:
return os.Getenv("HOME")
}
}
// ImportPath returns the import path of the caller or an error, if any.
func ImportPath() (string, error) {
_, file, _, ok := runtime.Caller(1)
if !ok {
return "", fmt.Errorf("runtime.Caller failed")
}
gopath := Gopath()
for _, v := range filepath.SplitList(gopath) {
gp := filepath.Join(v, "src")
path, err := filepath.Rel(gp, file)
if err != nil {
continue
}
return filepath.Dir(path), nil
}
return "", fmt.Errorf("cannot determine import path using GOPATH=%s", gopath)
}