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path: root/src/pkg/bytes/bytes.go
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Diffstat (limited to 'src/pkg/bytes/bytes.go')
-rw-r--r--src/pkg/bytes/bytes.go249
1 files changed, 175 insertions, 74 deletions
diff --git a/src/pkg/bytes/bytes.go b/src/pkg/bytes/bytes.go
index 5119fce94..7d1426fb4 100644
--- a/src/pkg/bytes/bytes.go
+++ b/src/pkg/bytes/bytes.go
@@ -8,11 +8,12 @@ package bytes
import (
"unicode"
- "utf8"
+ "unicode/utf8"
)
// Compare returns an integer comparing the two byte arrays lexicographically.
// The result will be 0 if a==b, -1 if a < b, and +1 if a > b
+// A nil argument is equivalent to an empty slice.
func Compare(a, b []byte) int {
m := len(a)
if m > len(b) {
@@ -37,7 +38,10 @@ func Compare(a, b []byte) int {
}
// Equal returns a boolean reporting whether a == b.
-func Equal(a, b []byte) bool {
+// A nil argument is equivalent to an empty slice.
+func Equal(a, b []byte) bool
+
+func equalPortable(a, b []byte) bool {
if len(a) != len(b) {
return false
}
@@ -74,18 +78,38 @@ func explode(s []byte, n int) [][]byte {
// Count counts the number of non-overlapping instances of sep in s.
func Count(s, sep []byte) int {
- if len(sep) == 0 {
+ n := len(sep)
+ if n == 0 {
return utf8.RuneCount(s) + 1
}
+ if n > len(s) {
+ return 0
+ }
+ count := 0
c := sep[0]
- n := 0
- for i := 0; i+len(sep) <= len(s); i++ {
- if s[i] == c && (len(sep) == 1 || Equal(s[i:i+len(sep)], sep)) {
- n++
- i += len(sep) - 1
+ i := 0
+ t := s[:len(s)-n+1]
+ for i < len(t) {
+ if t[i] != c {
+ o := IndexByte(t[i:], c)
+ if o < 0 {
+ break
+ }
+ i += o
+ }
+ if n == 1 || Equal(s[i:i+n], sep) {
+ count++
+ i += n
+ continue
}
+ i++
}
- return n
+ return count
+}
+
+// Contains returns whether subslice is within b.
+func Contains(b, subslice []byte) bool {
+ return Index(b, subslice) != -1
}
// Index returns the index of the first instance of sep in s, or -1 if sep is not present in s.
@@ -94,11 +118,27 @@ func Index(s, sep []byte) int {
if n == 0 {
return 0
}
+ if n > len(s) {
+ return -1
+ }
c := sep[0]
- for i := 0; i+n <= len(s); i++ {
- if s[i] == c && (n == 1 || Equal(s[i:i+n], sep)) {
+ if n == 1 {
+ return IndexByte(s, c)
+ }
+ i := 0
+ t := s[:len(s)-n+1]
+ for i < len(t) {
+ if t[i] != c {
+ o := IndexByte(t[i:], c)
+ if o < 0 {
+ break
+ }
+ i += o
+ }
+ if Equal(s[i:i+n], sep) {
return i
}
+ i++
}
return -1
}
@@ -130,10 +170,10 @@ func LastIndex(s, sep []byte) int {
// IndexRune interprets s as a sequence of UTF-8-encoded Unicode code points.
// It returns the byte index of the first occurrence in s of the given rune.
// It returns -1 if rune is not present in s.
-func IndexRune(s []byte, rune int) int {
+func IndexRune(s []byte, r rune) int {
for i := 0; i < len(s); {
- r, size := utf8.DecodeRune(s[i:])
- if r == rune {
+ r1, size := utf8.DecodeRune(s[i:])
+ if r == r1 {
return i
}
i += size
@@ -147,16 +187,17 @@ func IndexRune(s []byte, rune int) int {
// point in common.
func IndexAny(s []byte, chars string) int {
if len(chars) > 0 {
- var rune, width int
+ var r rune
+ var width int
for i := 0; i < len(s); i += width {
- rune = int(s[i])
- if rune < utf8.RuneSelf {
+ r = rune(s[i])
+ if r < utf8.RuneSelf {
width = 1
} else {
- rune, width = utf8.DecodeRune(s[i:])
+ r, width = utf8.DecodeRune(s[i:])
}
- for _, r := range chars {
- if rune == r {
+ for _, ch := range chars {
+ if r == ch {
return i
}
}
@@ -172,10 +213,10 @@ func IndexAny(s []byte, chars string) int {
func LastIndexAny(s []byte, chars string) int {
if len(chars) > 0 {
for i := len(s); i > 0; {
- rune, size := utf8.DecodeLastRune(s[0:i])
+ r, size := utf8.DecodeLastRune(s[0:i])
i -= size
- for _, m := range chars {
- if rune == m {
+ for _, ch := range chars {
+ if r == ch {
return i
}
}
@@ -256,13 +297,13 @@ func Fields(s []byte) [][]byte {
// It splits the array s at each run of code points c satisfying f(c) and
// returns a slice of subarrays of s. If no code points in s satisfy f(c), an
// empty slice is returned.
-func FieldsFunc(s []byte, f func(int) bool) [][]byte {
+func FieldsFunc(s []byte, f func(rune) bool) [][]byte {
n := 0
inField := false
for i := 0; i < len(s); {
- rune, size := utf8.DecodeRune(s[i:])
+ r, size := utf8.DecodeRune(s[i:])
wasInField := inField
- inField = !f(rune)
+ inField = !f(r)
if inField && !wasInField {
n++
}
@@ -273,13 +314,13 @@ func FieldsFunc(s []byte, f func(int) bool) [][]byte {
na := 0
fieldStart := -1
for i := 0; i <= len(s) && na < n; {
- rune, size := utf8.DecodeRune(s[i:])
- if fieldStart < 0 && size > 0 && !f(rune) {
+ r, size := utf8.DecodeRune(s[i:])
+ if fieldStart < 0 && size > 0 && !f(r) {
fieldStart = i
i += size
continue
}
- if fieldStart >= 0 && (size == 0 || f(rune)) {
+ if fieldStart >= 0 && (size == 0 || f(r)) {
a[na] = s[fieldStart:i]
na++
fieldStart = -1
@@ -329,7 +370,7 @@ func HasSuffix(s, suffix []byte) bool {
// according to the mapping function. If mapping returns a negative value, the character is
// dropped from the string with no replacement. The characters in s and the
// output are interpreted as UTF-8-encoded Unicode code points.
-func Map(mapping func(rune int) int, s []byte) []byte {
+func Map(mapping func(r rune) rune, s []byte) []byte {
// In the worst case, the array can grow when mapped, making
// things unpleasant. But it's so rare we barge in assuming it's
// fine. It could also shrink but that falls out naturally.
@@ -338,20 +379,20 @@ func Map(mapping func(rune int) int, s []byte) []byte {
b := make([]byte, maxbytes)
for i := 0; i < len(s); {
wid := 1
- rune := int(s[i])
- if rune >= utf8.RuneSelf {
- rune, wid = utf8.DecodeRune(s[i:])
+ r := rune(s[i])
+ if r >= utf8.RuneSelf {
+ r, wid = utf8.DecodeRune(s[i:])
}
- rune = mapping(rune)
- if rune >= 0 {
- if nbytes+utf8.RuneLen(rune) > maxbytes {
+ r = mapping(r)
+ if r >= 0 {
+ if nbytes+utf8.RuneLen(r) > maxbytes {
// Grow the buffer.
maxbytes = maxbytes*2 + utf8.UTFMax
nb := make([]byte, maxbytes)
copy(nb, b[0:nbytes])
b = nb
}
- nbytes += utf8.EncodeRune(b[nbytes:maxbytes], rune)
+ nbytes += utf8.EncodeRune(b[nbytes:maxbytes], r)
}
i += wid
}
@@ -383,44 +424,44 @@ func ToTitle(s []byte) []byte { return Map(unicode.ToTitle, s) }
// ToUpperSpecial returns a copy of the byte array s with all Unicode letters mapped to their
// upper case, giving priority to the special casing rules.
func ToUpperSpecial(_case unicode.SpecialCase, s []byte) []byte {
- return Map(func(r int) int { return _case.ToUpper(r) }, s)
+ return Map(func(r rune) rune { return _case.ToUpper(r) }, s)
}
// ToLowerSpecial returns a copy of the byte array s with all Unicode letters mapped to their
// lower case, giving priority to the special casing rules.
func ToLowerSpecial(_case unicode.SpecialCase, s []byte) []byte {
- return Map(func(r int) int { return _case.ToLower(r) }, s)
+ return Map(func(r rune) rune { return _case.ToLower(r) }, s)
}
// ToTitleSpecial returns a copy of the byte array s with all Unicode letters mapped to their
// title case, giving priority to the special casing rules.
func ToTitleSpecial(_case unicode.SpecialCase, s []byte) []byte {
- return Map(func(r int) int { return _case.ToTitle(r) }, s)
+ return Map(func(r rune) rune { return _case.ToTitle(r) }, s)
}
// isSeparator reports whether the rune could mark a word boundary.
// TODO: update when package unicode captures more of the properties.
-func isSeparator(rune int) bool {
+func isSeparator(r rune) bool {
// ASCII alphanumerics and underscore are not separators
- if rune <= 0x7F {
+ if r <= 0x7F {
switch {
- case '0' <= rune && rune <= '9':
+ case '0' <= r && r <= '9':
return false
- case 'a' <= rune && rune <= 'z':
+ case 'a' <= r && r <= 'z':
return false
- case 'A' <= rune && rune <= 'Z':
+ case 'A' <= r && r <= 'Z':
return false
- case rune == '_':
+ case r == '_':
return false
}
return true
}
// Letters and digits are not separators
- if unicode.IsLetter(rune) || unicode.IsDigit(rune) {
+ if unicode.IsLetter(r) || unicode.IsDigit(r) {
return false
}
// Otherwise, all we can do for now is treat spaces as separators.
- return unicode.IsSpace(rune)
+ return unicode.IsSpace(r)
}
// BUG(r): The rule Title uses for word boundaries does not handle Unicode punctuation properly.
@@ -433,7 +474,7 @@ func Title(s []byte) []byte {
// the closure once per rune.
prev := ' '
return Map(
- func(r int) int {
+ func(r rune) rune {
if isSeparator(prev) {
prev = r
return unicode.ToTitle(r)
@@ -446,7 +487,7 @@ func Title(s []byte) []byte {
// TrimLeftFunc returns a subslice of s by slicing off all leading UTF-8-encoded
// Unicode code points c that satisfy f(c).
-func TrimLeftFunc(s []byte, f func(r int) bool) []byte {
+func TrimLeftFunc(s []byte, f func(r rune) bool) []byte {
i := indexFunc(s, f, false)
if i == -1 {
return nil
@@ -456,7 +497,7 @@ func TrimLeftFunc(s []byte, f func(r int) bool) []byte {
// TrimRightFunc returns a subslice of s by slicing off all trailing UTF-8
// encoded Unicode code points c that satisfy f(c).
-func TrimRightFunc(s []byte, f func(r int) bool) []byte {
+func TrimRightFunc(s []byte, f func(r rune) bool) []byte {
i := lastIndexFunc(s, f, false)
if i >= 0 && s[i] >= utf8.RuneSelf {
_, wid := utf8.DecodeRune(s[i:])
@@ -469,36 +510,36 @@ func TrimRightFunc(s []byte, f func(r int) bool) []byte {
// TrimFunc returns a subslice of s by slicing off all leading and trailing
// UTF-8-encoded Unicode code points c that satisfy f(c).
-func TrimFunc(s []byte, f func(r int) bool) []byte {
+func TrimFunc(s []byte, f func(r rune) bool) []byte {
return TrimRightFunc(TrimLeftFunc(s, f), f)
}
// IndexFunc interprets s as a sequence of UTF-8-encoded Unicode code points.
// It returns the byte index in s of the first Unicode
// code point satisfying f(c), or -1 if none do.
-func IndexFunc(s []byte, f func(r int) bool) int {
+func IndexFunc(s []byte, f func(r rune) bool) int {
return indexFunc(s, f, true)
}
// LastIndexFunc interprets s as a sequence of UTF-8-encoded Unicode code points.
// It returns the byte index in s of the last Unicode
// code point satisfying f(c), or -1 if none do.
-func LastIndexFunc(s []byte, f func(r int) bool) int {
+func LastIndexFunc(s []byte, f func(r rune) bool) int {
return lastIndexFunc(s, f, true)
}
// indexFunc is the same as IndexFunc except that if
// truth==false, the sense of the predicate function is
// inverted.
-func indexFunc(s []byte, f func(r int) bool, truth bool) int {
+func indexFunc(s []byte, f func(r rune) bool, truth bool) int {
start := 0
for start < len(s) {
wid := 1
- rune := int(s[start])
- if rune >= utf8.RuneSelf {
- rune, wid = utf8.DecodeRune(s[start:])
+ r := rune(s[start])
+ if r >= utf8.RuneSelf {
+ r, wid = utf8.DecodeRune(s[start:])
}
- if f(rune) == truth {
+ if f(r) == truth {
return start
}
start += wid
@@ -509,21 +550,21 @@ func indexFunc(s []byte, f func(r int) bool, truth bool) int {
// lastIndexFunc is the same as LastIndexFunc except that if
// truth==false, the sense of the predicate function is
// inverted.
-func lastIndexFunc(s []byte, f func(r int) bool, truth bool) int {
+func lastIndexFunc(s []byte, f func(r rune) bool, truth bool) int {
for i := len(s); i > 0; {
- rune, size := utf8.DecodeLastRune(s[0:i])
+ r, size := utf8.DecodeLastRune(s[0:i])
i -= size
- if f(rune) == truth {
+ if f(r) == truth {
return i
}
}
return -1
}
-func makeCutsetFunc(cutset string) func(rune int) bool {
- return func(rune int) bool {
+func makeCutsetFunc(cutset string) func(r rune) bool {
+ return func(r rune) bool {
for _, c := range cutset {
- if c == rune {
+ if c == r {
return true
}
}
@@ -556,8 +597,8 @@ func TrimSpace(s []byte) []byte {
}
// Runes returns a slice of runes (Unicode code points) equivalent to s.
-func Runes(s []byte) []int {
- t := make([]int, utf8.RuneCount(s))
+func Runes(s []byte) []rune {
+ t := make([]rune, utf8.RuneCount(s))
i := 0
for len(s) > 0 {
r, l := utf8.DecodeRune(s)
@@ -572,13 +613,18 @@ func Runes(s []byte) []int {
// non-overlapping instances of old replaced by new.
// If n < 0, there is no limit on the number of replacements.
func Replace(s, old, new []byte, n int) []byte {
- if n == 0 {
- return s // avoid allocation
- }
- // Compute number of replacements.
- if m := Count(s, old); m == 0 {
- return s // avoid allocation
- } else if n <= 0 || m < n {
+ m := 0
+ if n != 0 {
+ // Compute number of replacements.
+ m = Count(s, old)
+ }
+ if m == 0 {
+ // Nothing to do. Just copy.
+ t := make([]byte, len(s))
+ copy(t, s)
+ return t
+ }
+ if n < 0 || m < n {
n = m
}
@@ -603,3 +649,58 @@ func Replace(s, old, new []byte, n int) []byte {
w += copy(t[w:], s[start:])
return t[0:w]
}
+
+// EqualFold reports whether s and t, interpreted as UTF-8 strings,
+// are equal under Unicode case-folding.
+func EqualFold(s, t []byte) bool {
+ for len(s) != 0 && len(t) != 0 {
+ // Extract first rune from each.
+ var sr, tr rune
+ if s[0] < utf8.RuneSelf {
+ sr, s = rune(s[0]), s[1:]
+ } else {
+ r, size := utf8.DecodeRune(s)
+ sr, s = r, s[size:]
+ }
+ if t[0] < utf8.RuneSelf {
+ tr, t = rune(t[0]), t[1:]
+ } else {
+ r, size := utf8.DecodeRune(t)
+ tr, t = r, t[size:]
+ }
+
+ // If they match, keep going; if not, return false.
+
+ // Easy case.
+ if tr == sr {
+ continue
+ }
+
+ // Make sr < tr to simplify what follows.
+ if tr < sr {
+ tr, sr = sr, tr
+ }
+ // Fast check for ASCII.
+ if tr < utf8.RuneSelf && 'A' <= sr && sr <= 'Z' {
+ // ASCII, and sr is upper case. tr must be lower case.
+ if tr == sr+'a'-'A' {
+ continue
+ }
+ return false
+ }
+
+ // General case. SimpleFold(x) returns the next equivalent rune > x
+ // or wraps around to smaller values.
+ r := unicode.SimpleFold(sr)
+ for r != sr && r < tr {
+ r = unicode.SimpleFold(r)
+ }
+ if r == tr {
+ continue
+ }
+ return false
+ }
+
+ // One string is empty. Are both?
+ return len(s) == len(t)
+}
generated by cgit v1.2.3 (git 2.39.1) at 2025-06-26 08:54:10 +0000