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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-16 19:19:13 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-16 19:19:13 +0000 |
commit | ccd992355df7192993c666236047820244914598 (patch) | |
tree | f00fea65147227b7743083c6148396f74cd66935 /src/encoding/json/fold.go | |
parent | Initial commit. (diff) | |
download | golang-1.21-ccd992355df7192993c666236047820244914598.tar.xz golang-1.21-ccd992355df7192993c666236047820244914598.zip |
Adding upstream version 1.21.8.upstream/1.21.8
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'src/encoding/json/fold.go')
-rw-r--r-- | src/encoding/json/fold.go | 48 |
1 files changed, 48 insertions, 0 deletions
diff --git a/src/encoding/json/fold.go b/src/encoding/json/fold.go new file mode 100644 index 0000000..c4c671b --- /dev/null +++ b/src/encoding/json/fold.go @@ -0,0 +1,48 @@ +// Copyright 2013 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 json + +import ( + "unicode" + "unicode/utf8" +) + +// foldName returns a folded string such that foldName(x) == foldName(y) +// is identical to bytes.EqualFold(x, y). +func foldName(in []byte) []byte { + // This is inlinable to take advantage of "function outlining". + var arr [32]byte // large enough for most JSON names + return appendFoldedName(arr[:0], in) +} + +func appendFoldedName(out, in []byte) []byte { + for i := 0; i < len(in); { + // Handle single-byte ASCII. + if c := in[i]; c < utf8.RuneSelf { + if 'a' <= c && c <= 'z' { + c -= 'a' - 'A' + } + out = append(out, c) + i++ + continue + } + // Handle multi-byte Unicode. + r, n := utf8.DecodeRune(in[i:]) + out = utf8.AppendRune(out, foldRune(r)) + i += n + } + return out +} + +// foldRune is returns the smallest rune for all runes in the same fold set. +func foldRune(r rune) rune { + for { + r2 := unicode.SimpleFold(r) + if r2 <= r { + return r2 + } + r = r2 + } +} |