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authorEmile <git@emile.space>2024-10-25 15:55:50 +0200
committerEmile <git@emile.space>2024-10-25 15:55:50 +0200
commitc90f36e3dd179d2de96f4f5fe38d8dc9a9de6dfe (patch)
tree89e9afb41c5bf76f48cfb09305a2d3db8d302b06 /vendor/golang.org/x/net/html/atom/atom.go
parent98bbb0f559a8883bc47bae80607dbe326a448e61 (diff)
vendor HEAD main
Diffstat (limited to 'vendor/golang.org/x/net/html/atom/atom.go')
-rw-r--r--vendor/golang.org/x/net/html/atom/atom.go78
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diff --git a/vendor/golang.org/x/net/html/atom/atom.go b/vendor/golang.org/x/net/html/atom/atom.go
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+// Copyright 2012 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 atom provides integer codes (also known as atoms) for a fixed set of
+// frequently occurring HTML strings: tag names and attribute keys such as "p"
+// and "id".
+//
+// Sharing an atom's name between all elements with the same tag can result in
+// fewer string allocations when tokenizing and parsing HTML. Integer
+// comparisons are also generally faster than string comparisons.
+//
+// The value of an atom's particular code is not guaranteed to stay the same
+// between versions of this package. Neither is any ordering guaranteed:
+// whether atom.H1 < atom.H2 may also change. The codes are not guaranteed to
+// be dense. The only guarantees are that e.g. looking up "div" will yield
+// atom.Div, calling atom.Div.String will return "div", and atom.Div != 0.
+package atom // import "golang.org/x/net/html/atom"
+
+// Atom is an integer code for a string. The zero value maps to "".
+type Atom uint32
+
+// String returns the atom's name.
+func (a Atom) String() string {
+	start := uint32(a >> 8)
+	n := uint32(a & 0xff)
+	if start+n > uint32(len(atomText)) {
+		return ""
+	}
+	return atomText[start : start+n]
+}
+
+func (a Atom) string() string {
+	return atomText[a>>8 : a>>8+a&0xff]
+}
+
+// fnv computes the FNV hash with an arbitrary starting value h.
+func fnv(h uint32, s []byte) uint32 {
+	for i := range s {
+		h ^= uint32(s[i])
+		h *= 16777619
+	}
+	return h
+}
+
+func match(s string, t []byte) bool {
+	for i, c := range t {
+		if s[i] != c {
+			return false
+		}
+	}
+	return true
+}
+
+// Lookup returns the atom whose name is s. It returns zero if there is no
+// such atom. The lookup is case sensitive.
+func Lookup(s []byte) Atom {
+	if len(s) == 0 || len(s) > maxAtomLen {
+		return 0
+	}
+	h := fnv(hash0, s)
+	if a := table[h&uint32(len(table)-1)]; int(a&0xff) == len(s) && match(a.string(), s) {
+		return a
+	}
+	if a := table[(h>>16)&uint32(len(table)-1)]; int(a&0xff) == len(s) && match(a.string(), s) {
+		return a
+	}
+	return 0
+}
+
+// String returns a string whose contents are equal to s. In that sense, it is
+// equivalent to string(s) but may be more efficient.
+func String(s []byte) string {
+	if a := Lookup(s); a != 0 {
+		return a.String()
+	}
+	return string(s)
+}