Source code analysis of Golang bytes

bytes/bytes.go source code analysis

Golang JDK 1.10.3

The [] byte s package provides common methods of operation.

 

Source code analysis

func equalPortable(a, b []byte) bool {
	if len(a) != len(b) {
		return false
	}
	for i, c := range a {
		if c != b[i] {
			return false
		}
	}
	return true
}

The equalPortable function is an internal function that compares whether the elements of two slices are equal.

 

// explode splits s into a slice of UTF-8 sequences, one per Unicode code point (still slices of bytes),
// up to a maximum of n byte slices. Invalid UTF-8 sequences are chopped into individual bytes.
func explode(s []byte, n int) [][]byte {
	if n <= 0 {
		n = len(s)
	}
	a := make([][]byte, n)
	var size int
	na := 0
	for len(s) > 0 {
		if na+1 >= n {
			a[na] = s
			na++
			break
		}
		_, size = utf8.DecodeRune(s)
		a[na] = s[0:size:size]
		s = s[size:]
		na++
	}
	return a[0:na]
}

The expand function is an internal function used to convert byte slices s into UTF-8 sequences

 

// countGeneric actually implements Count
func countGeneric(s, sep []byte) int {
	// special case
	if len(sep) == 0 {
		return utf8.RuneCount(s) + 1
	}
	n := 0
	for {
		i := Index(s, sep)
		if i == -1 {
			return n
		}
		n++
		s = s[i+len(sep):]
	}
}

The countGeneric function is also an internal function that returns the number of occurrences of sep in s. If sep is empty, the rune length of s is returned + 1

 

// Contains reports whether subslice is within b.
func Contains(b, subslice []byte) bool {
	return Index(b, subslice) != -1
}

Function: whether subslice slice is included in b

 

// ContainsAny reports whether any of the UTF-8-encoded code points in chars are within b.
func ContainsAny(b []byte, chars string) bool {
	return IndexAny(b, chars) >= 0
}

Function: judge whether slice b contains the string chanrs

 

// ContainsRune reports whether the rune is contained in the UTF-8-encoded byte slice b.
func ContainsRune(b []byte, r rune) bool {
	return IndexRune(b, r) >= 0
}

Function: judge whether the byte slice b contains UTF-8 character r

 

func indexBytePortable(s []byte, c byte) int {
	for i, b := range s {
		if b == c {
			return i
		}
	}
	return -1
}
indexBytePortable Function to return c stay s The index that appears for the first time in the slice s If yes, return-1

 

// LastIndex returns the index of the last instance of sep in s, or -1 if sep is not present in s.
func LastIndex(s, sep []byte) int {
	n := len(sep)
	if n == 0 {
		return len(s)
	}
	c := sep[0]
	for i := len(s) - n; i >= 0; i-- {
		if s[i] == c && (n == 1 || Equal(s[i:i+n], sep)) {
			return i
		}
	}
	return -1
}

The LastIndex function is used to obtain the index of the first occurrence of sep in S. if the sub slice sep is not included in slice s, it returns - 1

 

// LastIndexByte returns the index of the last instance of c in s, or -1 if c is not present in s.
func LastIndexByte(s []byte, c byte) int {
	for i := len(s) - 1; i >= 0; i-- {
		if s[i] == c {
			return i
		}
	}
	return -1
}

Function: get the index of the first occurrence of byte c in reverse order in slice s

 

// IndexRune interprets s as a sequence of UTF-8-encoded 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.
// If r is utf8.RuneError, it returns the first instance of any
// invalid UTF-8 byte sequence.
func IndexRune(s []byte, r rune) int {
	switch {
	case 0 <= r && r < utf8.RuneSelf:
		return IndexByte(s, byte(r))
	case r == utf8.RuneError:
		for i := 0; i < len(s); {
			r1, n := utf8.DecodeRune(s[i:])
			if r1 == utf8.RuneError {
				return i
			}
			i += n
		}
		return -1
	case !utf8.ValidRune(r):
		return -1
	default:
		var b [utf8.UTFMax]byte
		n := utf8.EncodeRune(b[:], r)
		return Index(s, b[:n])
	}
}

Function: get the index of the first occurrence of UTF-8 character r in byte slice s, and return - 1 if it is not included in slice s

 

// IndexAny interprets s as a sequence of UTF-8-encoded Unicode code points.
// It returns the byte index of the first occurrence in s of any of the Unicode
// code points in chars. It returns -1 if chars is empty or if there is no code
// point in common.
func IndexAny(s []byte, chars string) int {
	if chars == "" {
		// Avoid scanning all of s.
		return -1
	}
	if len(s) > 8 {
		if as, isASCII := makeASCIISet(chars); isASCII {
			for i, c := range s {
				if as.contains(c) {
					return i
				}
			}
			return -1
		}
	}
	var width int
	for i := 0; i < len(s); i += width {
		r := rune(s[i])
		if r < utf8.RuneSelf {
			width = 1
		} else {
			r, width = utf8.DecodeRune(s[i:])
		}
		for _, ch := range chars {
			if r == ch {
				return i
			}
		}
	}
	return -1
}

Function: find the position where any character in the string chars appears for the first time in slice s. if it cannot be found, return - 1

 

// LastIndexAny interprets s as a sequence of UTF-8-encoded Unicode code
// points. It returns the byte index of the last occurrence in s of any of
// the Unicode code points in chars. It returns -1 if chars is empty or if
// there is no code point in common.
func LastIndexAny(s []byte, chars string) int {
	if chars == "" {
		// Avoid scanning all of s.
		return -1
	}
	if len(s) > 8 {
		if as, isASCII := makeASCIISet(chars); isASCII {
			for i := len(s) - 1; i >= 0; i-- {
				if as.contains(s[i]) {
					return i
				}
			}
			return -1
		}
	}
	for i := len(s); i > 0; {
		r, size := utf8.DecodeLastRune(s[:i])
		i -= size
		for _, c := range chars {
			if r == c {
				return i
			}
		}
	}
	return -1
}

Function: find the position of the last occurrence of any character in chars in s. if it is not found, return - 1

 

// Generic split: splits after each instance of sep,
// including sepSave bytes of sep in the subslices.
func genSplit(s, sep []byte, sepSave, n int) [][]byte {
	if n == 0 {
		return nil
	}
	if len(sep) == 0 {
		return explode(s, n)
	}
	if n < 0 {
		n = Count(s, sep) + 1
	}

	a := make([][]byte, n)
	n--
	i := 0
	for i < n {
		m := Index(s, sep)
		if m < 0 {
			break
		}
		a[i] = s[: m+sepSave : m+sepSave]
		s = s[m+len(sep):]
		i++
	}
	a[i] = s
	return a[:i+1]
}

genSplit function, split s according to sep, sepSave is the number of + sepSave bytes in the sub slice, n is the number of segmentation, and if n is a negative number, it will be segmented

 

// SplitN slices s into subslices separated by sep and returns a slice of
// the subslices between those separators.
// If sep is empty, SplitN splits after each UTF-8 sequence.
// The count determines the number of subslices to return:
//   n > 0: at most n subslices; the last subslice will be the unsplit remainder.
//   n == 0: the result is nil (zero subslices)
//   n < 0: all subslices
func SplitN(s, sep []byte, n int) [][]byte { return genSplit(s, sep, 0, n) }

Function: slice s is divided into n slices according to sep. note: SEPs are not included after segmentation

 

// SplitAfterN slices s into subslices after each instance of sep and
// returns a slice of those subslices.
// If sep is empty, SplitAfterN splits after each UTF-8 sequence.
// The count determines the number of subslices to return:
//   n > 0: at most n subslices; the last subslice will be the unsplit remainder.
//   n == 0: the result is nil (zero subslices)
//   n < 0: all subslices
func SplitAfterN(s, sep []byte, n int) [][]byte {
	return genSplit(s, sep, len(sep), n)
}

Function: slice s into n slices according to sep, and the separator sep is included after the slice

 

// Split slices s into all subslices separated by sep and returns a slice of
// the subslices between those separators.
// If sep is empty, Split splits after each UTF-8 sequence.
// It is equivalent to SplitN with a count of -1.
func Split(s, sep []byte) [][]byte { return genSplit(s, sep, 0, -1) }

Function: slice s according to sep. SEPs is not included after segmentation

 

// SplitAfter slices s into all subslices after each instance of sep and
// returns a slice of those subslices.
// If sep is empty, SplitAfter splits after each UTF-8 sequence.
// It is equivalent to SplitAfterN with a count of -1.
func SplitAfter(s, sep []byte) [][]byte {
	return genSplit(s, sep, len(sep), -1)
}

Function: segment s according to sep, and include separator sep after segmentation

 

// Fields interprets s as a sequence of UTF-8-encoded code points.
// It splits the slice s around each instance of one or more consecutive white space
// characters, as defined by unicode.IsSpace, returning a slice of subslices of s or an
// empty slice if s contains only white space.
func Fields(s []byte) [][]byte {
	// First count the fields.
	// This is an exact count if s is ASCII, otherwise it is an approximation.
	n := 0
	wasSpace := 1
	// setBits is used to track which bits are set in the bytes of s.
	setBits := uint8(0)
	for i := 0; i < len(s); i++ {
		r := s[i]
		setBits |= r
		isSpace := int(asciiSpace[r])
		n += wasSpace & ^isSpace
		wasSpace = isSpace
	}

	if setBits >= utf8.RuneSelf {
		// Some runes in the input slice are not ASCII.
		return FieldsFunc(s, unicode.IsSpace)
	}

	// ASCII fast path
	a := make([][]byte, n)
	na := 0
	fieldStart := 0
	i := 0
	// Skip spaces in the front of the input.
	for i < len(s) && asciiSpace[s[i]] != 0 {
		i++
	}
	fieldStart = i
	for i < len(s) {
		if asciiSpace[s[i]] == 0 {
			i++
			continue
		}
		a[na] = s[fieldStart:i:i]
		na++
		i++
		// Skip spaces in between fields.
		for i < len(s) && asciiSpace[s[i]] != 0 {
			i++
		}
		fieldStart = i
	}
	if fieldStart < len(s) { // Last field might end at EOF.
		a[na] = s[fieldStart:len(s):len(s)]
	}
	return a
}

Function: slice s according to \ t or \ n or \ v or \ f or \ r or space

 

// FieldsFunc interprets s as a sequence of UTF-8-encoded code points.
// It splits the slice s at each run of code points c satisfying f(c) and
// returns a slice of subslices of s. If all code points in s satisfy f(c), or
// len(s) == 0, an empty slice is returned.
// FieldsFunc makes no guarantees about the order in which it calls f(c).
// If f does not return consistent results for a given c, FieldsFunc may crash.
func FieldsFunc(s []byte, f func(rune) bool) [][]byte {
	// A span is used to record a slice of s of the form s[start:end].
	// The start index is inclusive and the end index is exclusive.
	type span struct {
		start int
		end   int
	}
	spans := make([]span, 0, 32)

	// Find the field start and end indices.
	wasField := false
	fromIndex := 0
	for i := 0; i < len(s); {
		size := 1
		r := rune(s[i])
		if r >= utf8.RuneSelf {
			r, size = utf8.DecodeRune(s[i:])
		}
		if f(r) {
			if wasField {
				spans = append(spans, span{start: fromIndex, end: i})
				wasField = false
			}
		} else {
			if !wasField {
				fromIndex = i
				wasField = true
			}
		}
		i += size
	}

	// Last field might end at EOF.
	if wasField {
		spans = append(spans, span{fromIndex, len(s)})
	}

	// Create subslices from recorded field indices.
	a := make([][]byte, len(spans))
	for i, span := range spans {
		a[i] = s[span.start:span.end:span.end]
	}

	return a
}

Function: slice s according to f function

 

// Join concatenates the elements of s to create a new byte slice. The separator
// sep is placed between elements in the resulting slice.
func Join(s [][]byte, sep []byte) []byte {
	if len(s) == 0 {
		return []byte{}
	}
	if len(s) == 1 {
		// Just return a copy.
		return append([]byte(nil), s[0]...)
	}
	n := len(sep) * (len(s) - 1)
	for _, v := range s {
		n += len(v)
	}

	b := make([]byte, n)
	bp := copy(b, s[0])
	for _, v := range s[1:] {
		bp += copy(b[bp:], sep)
		bp += copy(b[bp:], v)
	}
	return b
}

Function: connect s according to sep, which is the connector

 

// HasPrefix tests whether the byte slice s begins with prefix.
func HasPrefix(s, prefix []byte) bool {
	return len(s) >= len(prefix) && Equal(s[0:len(prefix)], prefix)
}

Function: judge whether s starts with prefix

 

// HasSuffix tests whether the byte slice s ends with suffix.
func HasSuffix(s, suffix []byte) bool {
	return len(s) >= len(suffix) && Equal(s[len(s)-len(suffix):], suffix)
}

Function: judge whether the slice s ends with suffix

 

// Map returns a copy of the byte slice s with all its characters modified
// according to the mapping function. If mapping returns a negative value, the character is
// dropped from the byte slice with no replacement. The characters in s and the
// output are interpreted as UTF-8-encoded code points.
func Map(mapping func(r rune) rune, s []byte) []byte {
	// In the worst case, the slice 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.
	maxbytes := len(s) // length of b
	nbytes := 0        // number of bytes encoded in b
	b := make([]byte, maxbytes)
	for i := 0; i < len(s); {
		wid := 1
		r := rune(s[i])
		if r >= utf8.RuneSelf {
			r, wid = utf8.DecodeRune(s[i:])
		}
		r = mapping(r)
		if r >= 0 {
			rl := utf8.RuneLen(r)
			if rl < 0 {
				rl = len(string(utf8.RuneError))
			}
			if nbytes+rl > 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], r)
		}
		i += wid
	}
	return b[0:nbytes]
}

Function: generate new slice s according to mapping function

 

// Repeat returns a new byte slice consisting of count copies of b.
//
// It panics if count is negative or if
// the result of (len(b) * count) overflows.
func Repeat(b []byte, count int) []byte {
	// Since we cannot return an error on overflow,
	// we should panic if the repeat will generate
	// an overflow.
	// See Issue golang.org/issue/16237.
	if count < 0 {
		panic("bytes: negative Repeat count")
	} else if count > 0 && len(b)*count/count != len(b) {
		panic("bytes: Repeat count causes overflow")
	}

	nb := make([]byte, len(b)*count)
	bp := copy(nb, b)
	for bp < len(nb) {
		copy(nb[bp:], nb[:bp])
		bp *= 2
	}
	return nb
}

Function: fill count B slices, that is, the returned slices are filled with count B slices, and the length of the returned slices is: len(b)*count

 

// ToUpper treats s as UTF-8-encoded bytes and returns a copy with all the Unicode letters within it mapped to their upper case.
func ToUpper(s []byte) []byte { return Map(unicode.ToUpper, s) }

Function: convert each byte element in the slice to uppercase

 

// ToLower treats s as UTF-8-encoded bytes and returns a copy with all the Unicode letters mapped to their lower case.
func ToLower(s []byte) []byte { return Map(unicode.ToLower, s) }

Function: convert each byte element in the slice to lowercase

 

// ToTitle treats s as UTF-8-encoded bytes and returns a copy with all the Unicode letters mapped to their title case.
func ToTitle(s []byte) []byte { return Map(unicode.ToTitle, s) }

Function: modify all characters in {s to Title format and return

 

// ToUpperSpecial treats s as UTF-8-encoded bytes and returns a copy with all the Unicode letters mapped to their
// upper case, giving priority to the special casing rules.
func ToUpperSpecial(c unicode.SpecialCase, s []byte) []byte {
	return Map(func(r rune) rune { return c.ToUpper(r) }, s)
}

Function: use the specified mapping table to modify all characters in s to uppercase format and return.

 

// ToLowerSpecial treats s as UTF-8-encoded bytes and returns a copy with all the Unicode letters mapped to their
// lower case, giving priority to the special casing rules.
func ToLowerSpecial(c unicode.SpecialCase, s []byte) []byte {
	return Map(func(r rune) rune { return c.ToLower(r) }, s)
}

Function: use the specified mapping table to modify all characters in s to be returned in lowercase format.

 

// ToTitleSpecial treats s as UTF-8-encoded bytes and returns a copy with all the Unicode letters mapped to their
// title case, giving priority to the special casing rules.
func ToTitleSpecial(c unicode.SpecialCase, s []byte) []byte {
	return Map(func(r rune) rune { return c.ToTitle(r) }, s)
}

Function: use the specified mapping table to modify all characters in slice s to return in title format.

 

// isSeparator reports whether the rune could mark a word boundary.
// TODO: update when package unicode captures more of the properties.
func isSeparator(r rune) bool {
	// ASCII alphanumerics and underscore are not separators
	if r <= 0x7F {
		switch {
		case '0' <= r && r <= '9':
			return false
		case 'a' <= r && r <= 'z':
			return false
		case 'A' <= r && r <= 'Z':
			return false
		case r == '_':
			return false
		}
		return true
	}
	// Letters and digits are not separators
	if unicode.IsLetter(r) || unicode.IsDigit(r) {
		return false
	}
	// Otherwise, all we can do for now is treat spaces as separators.
	return unicode.IsSpace(r)
}

The isSeparator method determines whether it is a separator

 

// Title treats s as UTF-8-encoded bytes and returns a copy with all Unicode letters that begin
// words mapped to their title case.
//
// BUG(rsc): The rule Title uses for word boundaries does not handle Unicode punctuation properly.
func Title(s []byte) []byte {
	// Use a closure here to remember state.
	// Hackish but effective. Depends on Map scanning in order and calling
	// the closure once per rune.
	prev := ' '
	return Map(
		func(r rune) rune {
			if isSeparator(prev) {
				prev = r
				return unicode.ToTitle(r)
			}
			prev = r
			return r
		},
		s)
}

Function: modify the first character of all words in slice s to return in Title format.

 

// TrimLeftFunc treats s as UTF-8-encoded bytes and returns a subslice of s by slicing off
// all leading UTF-8-encoded code points c that satisfy f(c).
func TrimLeftFunc(s []byte, f func(r rune) bool) []byte {
	i := indexFunc(s, f, false)
	if i == -1 {
		return nil
	}
	return s[i:]
}

Function: remove the elements on the left side of slice s that conform to the f function

 

// TrimRightFunc returns a subslice of s by slicing off all trailing
// UTF-8-encoded code points c that satisfy f(c).
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:])
		i += wid
	} else {
		i++
	}
	return s[0:i]
}

Function: remove the elements conforming to the f function on the right side of slice s

 

// TrimFunc returns a subslice of s by slicing off all leading and trailing
// UTF-8-encoded code points c that satisfy f(c).
func TrimFunc(s []byte, f func(r rune) bool) []byte {
	return TrimRightFunc(TrimLeftFunc(s, f), f)
}

Function: remove the elements conforming to the f function on both sides of the slice s

 

// TrimPrefix returns s without the provided leading prefix string.
// If s doesn't start with prefix, s is returned unchanged.
func TrimPrefix(s, prefix []byte) []byte {
	if HasPrefix(s, prefix) {
		return s[len(prefix):]
	}
	return s
}

Function: remove the prefix slice in front of slice S. if the prefix is not the head of S, it will not be removed and directly return to slice s

 

// TrimSuffix returns s without the provided trailing suffix string.
// If s doesn't end with suffix, s is returned unchanged.
func TrimSuffix(s, suffix []byte) []byte {
	if HasSuffix(s, suffix) {
		return s[:len(s)-len(suffix)]
	}
	return s
}

Function: remove the suffix of slice s. if suffix is not the tail of s, no removal operation will be performed

 

// IndexFunc interprets s as a sequence of UTF-8-encoded 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 rune) bool) int {
	return indexFunc(s, f, true)
}

Function: find the position where the character matching f first appears in s. if it cannot be found, return - 1.

 

// LastIndexFunc interprets s as a sequence of UTF-8-encoded 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 rune) bool) int {
	return lastIndexFunc(s, f, true)
}

Function: find the position of the last occurrence of the character matching f in s. if it is not found, return - 1.

 

// Trim returns a subslice of s by slicing off all leading and
// trailing UTF-8-encoded code points contained in cutset.
func Trim(s []byte, cutset string) []byte {
	return TrimFunc(s, makeCutsetFunc(cutset))
}

Function: remove the elements that match the cutset string at the front and back ends of slice s

 

// TrimLeft returns a subslice of s by slicing off all leading
// UTF-8-encoded code points contained in cutset.
func TrimLeft(s []byte, cutset string) []byte {
	return TrimLeftFunc(s, makeCutsetFunc(cutset))
}

Function: remove the cutset compliant element on the left side of slice s

 

// TrimRight returns a subslice of s by slicing off all trailing
// UTF-8-encoded code points that are contained in cutset.
func TrimRight(s []byte, cutset string) []byte {
	return TrimRightFunc(s, makeCutsetFunc(cutset))
}

Function: remove the element matching the cutset string on the right side of slice s

 

// TrimSpace returns a subslice of s by slicing off all leading and
// trailing white space, as defined by Unicode.
func TrimSpace(s []byte) []byte {
	return TrimFunc(s, unicode.IsSpace)
}

Function: remove the left and right spaces in slice s

 

// Runes interprets s as a sequence of UTF-8-encoded code points.
// It returns a slice of runes (Unicode code points) equivalent to s.
func Runes(s []byte) []rune {
	t := make([]rune, utf8.RuneCount(s))
	i := 0
	for len(s) > 0 {
		r, l := utf8.DecodeRune(s)
		t[i] = r
		i++
		s = s[l:]
	}
	return t
}

Function: install UTF-8 encoding of byte array and convert it into [] rune slice

 

// Replace returns a copy of the slice s with the first n
// non-overlapping instances of old replaced by new.
// If old is empty, it matches at the beginning of the slice
// and after each UTF-8 sequence, yielding up to k+1 replacements
// for a k-rune slice.
// If n < 0, there is no limit on the number of replacements.
func Replace(s, old, new []byte, n int) []byte {
	m := 0
	if n != 0 {
		// Compute number of replacements.
		m = Count(s, old)
	}
	if m == 0 {
		// Just return a copy.
		return append([]byte(nil), s...)
	}
	if n < 0 || m < n {
		n = m
	}

	// Apply replacements to buffer.
	t := make([]byte, len(s)+n*(len(new)-len(old)))
	w := 0
	start := 0
	for i := 0; i < n; i++ {
		j := start
		if len(old) == 0 {
			if i > 0 {
				_, wid := utf8.DecodeRune(s[start:])
				j += wid
			}
		} else {
			j += Index(s[start:], old)
		}
		w += copy(t[w:], s[start:j])
		w += copy(t[w:], new)
		start = j + len(old)
	}
	w += copy(t[w:], s[start:])
	return t[0:w]
}

Function: replace the old slice element in s slice with new slice, and n is the number of replacements

 

// 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)
}

Function: judge whether slice s and t are equal, ignoring case

 

func IndexByte(s []byte, c byte) int

Function: the index of the first occurrence of byte c in slice S. if it is not included in slice s, it returns - 1

 

func Equal(a, b []byte) bool

Function: judge whether two slices a and b want to wait

 

func Compare(a, b []byte) int

Function: used to compare two slices a and b

A > b return 1

A < B return - 1

a == b returns 0

Posted by MindOverBody on Mon, 23 May 2022 22:25:31 +0300