diff options
Diffstat (limited to 'src/encoding/base32/base32.go')
| -rw-r--r-- | src/encoding/base32/base32.go | 14 |
1 files changed, 12 insertions, 2 deletions
diff --git a/src/encoding/base32/base32.go b/src/encoding/base32/base32.go index de95df0043..e921887285 100644 --- a/src/encoding/base32/base32.go +++ b/src/encoding/base32/base32.go @@ -402,7 +402,13 @@ func (enc *Encoding) Decode(dst, src []byte) (n int, err error) { // and returns the extended buffer. // If the input is malformed, it returns the partially decoded src and an error. func (enc *Encoding) AppendDecode(dst, src []byte) ([]byte, error) { - n := enc.DecodedLen(len(src)) + // Compute the output size without padding to avoid over allocating. + n := len(src) + for n > 0 && rune(src[n-1]) == enc.padChar { + n-- + } + n = decodedLen(n, NoPadding) + dst = slices.Grow(dst, n) n, err := enc.Decode(dst[len(dst):][:n], src) return dst[:len(dst)+n], err @@ -567,7 +573,11 @@ func NewDecoder(enc *Encoding, r io.Reader) io.Reader { // DecodedLen returns the maximum length in bytes of the decoded data // corresponding to n bytes of base32-encoded data. func (enc *Encoding) DecodedLen(n int) int { - if enc.padChar == NoPadding { + return decodedLen(n, enc.padChar) +} + +func decodedLen(n int, padChar rune) int { + if padChar == NoPadding { return n/8*5 + n%8*5/8 } return n / 8 * 5 |