diff options
Diffstat (limited to 'src/bytes/bytes.go')
| -rw-r--r-- | src/bytes/bytes.go | 23 |
1 files changed, 19 insertions, 4 deletions
diff --git a/src/bytes/bytes.go b/src/bytes/bytes.go index 5dfc441b81..40c7c23cd7 100644 --- a/src/bytes/bytes.go +++ b/src/bytes/bytes.go @@ -130,13 +130,28 @@ func LastIndexByte(s []byte, c 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. +// If r is utf8.RuneError, it returns the first instance of any +// invalid UTF-8 byte sequence. func IndexRune(s []byte, r rune) int { - if r < utf8.RuneSelf { + 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]) } - var b [utf8.UTFMax]byte - n := utf8.EncodeRune(b[:], r) - return Index(s, b[:n]) } // IndexAny interprets s as a sequence of UTF-8-encoded Unicode code points. |