mirror of
https://github.com/autc04/Retro68.git
synced 2024-09-06 22:54:33 +00:00
443 lines
11 KiB
Go
443 lines
11 KiB
Go
// Copyright 2009 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 strconv
|
|
|
|
import (
|
|
"unicode/utf8"
|
|
)
|
|
|
|
const lowerhex = "0123456789abcdef"
|
|
|
|
func quoteWith(s string, quote byte, ASCIIonly bool) string {
|
|
var runeTmp [utf8.UTFMax]byte
|
|
buf := make([]byte, 0, 3*len(s)/2) // Try to avoid more allocations.
|
|
buf = append(buf, quote)
|
|
for width := 0; len(s) > 0; s = s[width:] {
|
|
r := rune(s[0])
|
|
width = 1
|
|
if r >= utf8.RuneSelf {
|
|
r, width = utf8.DecodeRuneInString(s)
|
|
}
|
|
if width == 1 && r == utf8.RuneError {
|
|
buf = append(buf, `\x`...)
|
|
buf = append(buf, lowerhex[s[0]>>4])
|
|
buf = append(buf, lowerhex[s[0]&0xF])
|
|
continue
|
|
}
|
|
if r == rune(quote) || r == '\\' { // always backslashed
|
|
buf = append(buf, '\\')
|
|
buf = append(buf, byte(r))
|
|
continue
|
|
}
|
|
if ASCIIonly {
|
|
if r < utf8.RuneSelf && IsPrint(r) {
|
|
buf = append(buf, byte(r))
|
|
continue
|
|
}
|
|
} else if IsPrint(r) {
|
|
n := utf8.EncodeRune(runeTmp[:], r)
|
|
buf = append(buf, runeTmp[:n]...)
|
|
continue
|
|
}
|
|
switch r {
|
|
case '\a':
|
|
buf = append(buf, `\a`...)
|
|
case '\b':
|
|
buf = append(buf, `\b`...)
|
|
case '\f':
|
|
buf = append(buf, `\f`...)
|
|
case '\n':
|
|
buf = append(buf, `\n`...)
|
|
case '\r':
|
|
buf = append(buf, `\r`...)
|
|
case '\t':
|
|
buf = append(buf, `\t`...)
|
|
case '\v':
|
|
buf = append(buf, `\v`...)
|
|
default:
|
|
switch {
|
|
case r < ' ':
|
|
buf = append(buf, `\x`...)
|
|
buf = append(buf, lowerhex[s[0]>>4])
|
|
buf = append(buf, lowerhex[s[0]&0xF])
|
|
case r > utf8.MaxRune:
|
|
r = 0xFFFD
|
|
fallthrough
|
|
case r < 0x10000:
|
|
buf = append(buf, `\u`...)
|
|
for s := 12; s >= 0; s -= 4 {
|
|
buf = append(buf, lowerhex[r>>uint(s)&0xF])
|
|
}
|
|
default:
|
|
buf = append(buf, `\U`...)
|
|
for s := 28; s >= 0; s -= 4 {
|
|
buf = append(buf, lowerhex[r>>uint(s)&0xF])
|
|
}
|
|
}
|
|
}
|
|
}
|
|
buf = append(buf, quote)
|
|
return string(buf)
|
|
|
|
}
|
|
|
|
// Quote returns a double-quoted Go string literal representing s. The
|
|
// returned string uses Go escape sequences (\t, \n, \xFF, \u0100) for
|
|
// control characters and non-printable characters as defined by
|
|
// IsPrint.
|
|
func Quote(s string) string {
|
|
return quoteWith(s, '"', false)
|
|
}
|
|
|
|
// AppendQuote appends a double-quoted Go string literal representing s,
|
|
// as generated by Quote, to dst and returns the extended buffer.
|
|
func AppendQuote(dst []byte, s string) []byte {
|
|
return append(dst, Quote(s)...)
|
|
}
|
|
|
|
// QuoteToASCII returns a double-quoted Go string literal representing s.
|
|
// The returned string uses Go escape sequences (\t, \n, \xFF, \u0100) for
|
|
// non-ASCII characters and non-printable characters as defined by IsPrint.
|
|
func QuoteToASCII(s string) string {
|
|
return quoteWith(s, '"', true)
|
|
}
|
|
|
|
// AppendQuoteToASCII appends a double-quoted Go string literal representing s,
|
|
// as generated by QuoteToASCII, to dst and returns the extended buffer.
|
|
func AppendQuoteToASCII(dst []byte, s string) []byte {
|
|
return append(dst, QuoteToASCII(s)...)
|
|
}
|
|
|
|
// QuoteRune returns a single-quoted Go character literal representing the
|
|
// rune. The returned string uses Go escape sequences (\t, \n, \xFF, \u0100)
|
|
// for control characters and non-printable characters as defined by IsPrint.
|
|
func QuoteRune(r rune) string {
|
|
// TODO: avoid the allocation here.
|
|
return quoteWith(string(r), '\'', false)
|
|
}
|
|
|
|
// AppendQuoteRune appends a single-quoted Go character literal representing the rune,
|
|
// as generated by QuoteRune, to dst and returns the extended buffer.
|
|
func AppendQuoteRune(dst []byte, r rune) []byte {
|
|
return append(dst, QuoteRune(r)...)
|
|
}
|
|
|
|
// QuoteRuneToASCII returns a single-quoted Go character literal representing
|
|
// the rune. The returned string uses Go escape sequences (\t, \n, \xFF,
|
|
// \u0100) for non-ASCII characters and non-printable characters as defined
|
|
// by IsPrint.
|
|
func QuoteRuneToASCII(r rune) string {
|
|
// TODO: avoid the allocation here.
|
|
return quoteWith(string(r), '\'', true)
|
|
}
|
|
|
|
// AppendQuoteRuneToASCII appends a single-quoted Go character literal representing the rune,
|
|
// as generated by QuoteRuneToASCII, to dst and returns the extended buffer.
|
|
func AppendQuoteRuneToASCII(dst []byte, r rune) []byte {
|
|
return append(dst, QuoteRuneToASCII(r)...)
|
|
}
|
|
|
|
// CanBackquote reports whether the string s can be represented
|
|
// unchanged as a single-line backquoted string without control
|
|
// characters other than space and tab.
|
|
func CanBackquote(s string) bool {
|
|
for i := 0; i < len(s); i++ {
|
|
if (s[i] < ' ' && s[i] != '\t') || s[i] == '`' {
|
|
return false
|
|
}
|
|
}
|
|
return true
|
|
}
|
|
|
|
func unhex(b byte) (v rune, ok bool) {
|
|
c := rune(b)
|
|
switch {
|
|
case '0' <= c && c <= '9':
|
|
return c - '0', true
|
|
case 'a' <= c && c <= 'f':
|
|
return c - 'a' + 10, true
|
|
case 'A' <= c && c <= 'F':
|
|
return c - 'A' + 10, true
|
|
}
|
|
return
|
|
}
|
|
|
|
// UnquoteChar decodes the first character or byte in the escaped string
|
|
// or character literal represented by the string s.
|
|
// It returns four values:
|
|
//
|
|
// 1) value, the decoded Unicode code point or byte value;
|
|
// 2) multibyte, a boolean indicating whether the decoded character requires a multibyte UTF-8 representation;
|
|
// 3) tail, the remainder of the string after the character; and
|
|
// 4) an error that will be nil if the character is syntactically valid.
|
|
//
|
|
// The second argument, quote, specifies the type of literal being parsed
|
|
// and therefore which escaped quote character is permitted.
|
|
// If set to a single quote, it permits the sequence \' and disallows unescaped '.
|
|
// If set to a double quote, it permits \" and disallows unescaped ".
|
|
// If set to zero, it does not permit either escape and allows both quote characters to appear unescaped.
|
|
func UnquoteChar(s string, quote byte) (value rune, multibyte bool, tail string, err error) {
|
|
// easy cases
|
|
switch c := s[0]; {
|
|
case c == quote && (quote == '\'' || quote == '"'):
|
|
err = ErrSyntax
|
|
return
|
|
case c >= utf8.RuneSelf:
|
|
r, size := utf8.DecodeRuneInString(s)
|
|
return r, true, s[size:], nil
|
|
case c != '\\':
|
|
return rune(s[0]), false, s[1:], nil
|
|
}
|
|
|
|
// hard case: c is backslash
|
|
if len(s) <= 1 {
|
|
err = ErrSyntax
|
|
return
|
|
}
|
|
c := s[1]
|
|
s = s[2:]
|
|
|
|
switch c {
|
|
case 'a':
|
|
value = '\a'
|
|
case 'b':
|
|
value = '\b'
|
|
case 'f':
|
|
value = '\f'
|
|
case 'n':
|
|
value = '\n'
|
|
case 'r':
|
|
value = '\r'
|
|
case 't':
|
|
value = '\t'
|
|
case 'v':
|
|
value = '\v'
|
|
case 'x', 'u', 'U':
|
|
n := 0
|
|
switch c {
|
|
case 'x':
|
|
n = 2
|
|
case 'u':
|
|
n = 4
|
|
case 'U':
|
|
n = 8
|
|
}
|
|
var v rune
|
|
if len(s) < n {
|
|
err = ErrSyntax
|
|
return
|
|
}
|
|
for j := 0; j < n; j++ {
|
|
x, ok := unhex(s[j])
|
|
if !ok {
|
|
err = ErrSyntax
|
|
return
|
|
}
|
|
v = v<<4 | x
|
|
}
|
|
s = s[n:]
|
|
if c == 'x' {
|
|
// single-byte string, possibly not UTF-8
|
|
value = v
|
|
break
|
|
}
|
|
if v > utf8.MaxRune {
|
|
err = ErrSyntax
|
|
return
|
|
}
|
|
value = v
|
|
multibyte = true
|
|
case '0', '1', '2', '3', '4', '5', '6', '7':
|
|
v := rune(c) - '0'
|
|
if len(s) < 2 {
|
|
err = ErrSyntax
|
|
return
|
|
}
|
|
for j := 0; j < 2; j++ { // one digit already; two more
|
|
x := rune(s[j]) - '0'
|
|
if x < 0 || x > 7 {
|
|
err = ErrSyntax
|
|
return
|
|
}
|
|
v = (v << 3) | x
|
|
}
|
|
s = s[2:]
|
|
if v > 255 {
|
|
err = ErrSyntax
|
|
return
|
|
}
|
|
value = v
|
|
case '\\':
|
|
value = '\\'
|
|
case '\'', '"':
|
|
if c != quote {
|
|
err = ErrSyntax
|
|
return
|
|
}
|
|
value = rune(c)
|
|
default:
|
|
err = ErrSyntax
|
|
return
|
|
}
|
|
tail = s
|
|
return
|
|
}
|
|
|
|
// Unquote interprets s as a single-quoted, double-quoted,
|
|
// or backquoted Go string literal, returning the string value
|
|
// that s quotes. (If s is single-quoted, it would be a Go
|
|
// character literal; Unquote returns the corresponding
|
|
// one-character string.)
|
|
func Unquote(s string) (t string, err error) {
|
|
n := len(s)
|
|
if n < 2 {
|
|
return "", ErrSyntax
|
|
}
|
|
quote := s[0]
|
|
if quote != s[n-1] {
|
|
return "", ErrSyntax
|
|
}
|
|
s = s[1 : n-1]
|
|
|
|
if quote == '`' {
|
|
if contains(s, '`') {
|
|
return "", ErrSyntax
|
|
}
|
|
return s, nil
|
|
}
|
|
if quote != '"' && quote != '\'' {
|
|
return "", ErrSyntax
|
|
}
|
|
if contains(s, '\n') {
|
|
return "", ErrSyntax
|
|
}
|
|
|
|
// Is it trivial? Avoid allocation.
|
|
if !contains(s, '\\') && !contains(s, quote) {
|
|
switch quote {
|
|
case '"':
|
|
return s, nil
|
|
case '\'':
|
|
r, size := utf8.DecodeRuneInString(s)
|
|
if size == len(s) && (r != utf8.RuneError || size != 1) {
|
|
return s, nil
|
|
}
|
|
}
|
|
}
|
|
|
|
var runeTmp [utf8.UTFMax]byte
|
|
buf := make([]byte, 0, 3*len(s)/2) // Try to avoid more allocations.
|
|
for len(s) > 0 {
|
|
c, multibyte, ss, err := UnquoteChar(s, quote)
|
|
if err != nil {
|
|
return "", err
|
|
}
|
|
s = ss
|
|
if c < utf8.RuneSelf || !multibyte {
|
|
buf = append(buf, byte(c))
|
|
} else {
|
|
n := utf8.EncodeRune(runeTmp[:], c)
|
|
buf = append(buf, runeTmp[:n]...)
|
|
}
|
|
if quote == '\'' && len(s) != 0 {
|
|
// single-quoted must be single character
|
|
return "", ErrSyntax
|
|
}
|
|
}
|
|
return string(buf), nil
|
|
}
|
|
|
|
// contains reports whether the string contains the byte c.
|
|
func contains(s string, c byte) bool {
|
|
for i := 0; i < len(s); i++ {
|
|
if s[i] == c {
|
|
return true
|
|
}
|
|
}
|
|
return false
|
|
}
|
|
|
|
// bsearch16 returns the smallest i such that a[i] >= x.
|
|
// If there is no such i, bsearch16 returns len(a).
|
|
func bsearch16(a []uint16, x uint16) int {
|
|
i, j := 0, len(a)
|
|
for i < j {
|
|
h := i + (j-i)/2
|
|
if a[h] < x {
|
|
i = h + 1
|
|
} else {
|
|
j = h
|
|
}
|
|
}
|
|
return i
|
|
}
|
|
|
|
// bsearch32 returns the smallest i such that a[i] >= x.
|
|
// If there is no such i, bsearch32 returns len(a).
|
|
func bsearch32(a []uint32, x uint32) int {
|
|
i, j := 0, len(a)
|
|
for i < j {
|
|
h := i + (j-i)/2
|
|
if a[h] < x {
|
|
i = h + 1
|
|
} else {
|
|
j = h
|
|
}
|
|
}
|
|
return i
|
|
}
|
|
|
|
// TODO: IsPrint is a local implementation of unicode.IsPrint, verified by the tests
|
|
// to give the same answer. It allows this package not to depend on unicode,
|
|
// and therefore not pull in all the Unicode tables. If the linker were better
|
|
// at tossing unused tables, we could get rid of this implementation.
|
|
// That would be nice.
|
|
|
|
// IsPrint reports whether the rune is defined as printable by Go, with
|
|
// the same definition as unicode.IsPrint: letters, numbers, punctuation,
|
|
// symbols and ASCII space.
|
|
func IsPrint(r rune) bool {
|
|
// Fast check for Latin-1
|
|
if r <= 0xFF {
|
|
if 0x20 <= r && r <= 0x7E {
|
|
// All the ASCII is printable from space through DEL-1.
|
|
return true
|
|
}
|
|
if 0xA1 <= r && r <= 0xFF {
|
|
// Similarly for ¡ through ÿ...
|
|
return r != 0xAD // ...except for the bizarre soft hyphen.
|
|
}
|
|
return false
|
|
}
|
|
|
|
// Same algorithm, either on uint16 or uint32 value.
|
|
// First, find first i such that isPrint[i] >= x.
|
|
// This is the index of either the start or end of a pair that might span x.
|
|
// The start is even (isPrint[i&^1]) and the end is odd (isPrint[i|1]).
|
|
// If we find x in a range, make sure x is not in isNotPrint list.
|
|
|
|
if 0 <= r && r < 1<<16 {
|
|
rr, isPrint, isNotPrint := uint16(r), isPrint16, isNotPrint16
|
|
i := bsearch16(isPrint, rr)
|
|
if i >= len(isPrint) || rr < isPrint[i&^1] || isPrint[i|1] < rr {
|
|
return false
|
|
}
|
|
j := bsearch16(isNotPrint, rr)
|
|
return j >= len(isNotPrint) || isNotPrint[j] != rr
|
|
}
|
|
|
|
rr, isPrint, isNotPrint := uint32(r), isPrint32, isNotPrint32
|
|
i := bsearch32(isPrint, rr)
|
|
if i >= len(isPrint) || rr < isPrint[i&^1] || isPrint[i|1] < rr {
|
|
return false
|
|
}
|
|
if r >= 0x20000 {
|
|
return true
|
|
}
|
|
r -= 0x10000
|
|
j := bsearch16(isNotPrint, uint16(r))
|
|
return j >= len(isNotPrint) || isNotPrint[j] != uint16(r)
|
|
}
|