diff options
Diffstat (limited to 'src/encoding/base64/base64.go')
| -rw-r--r-- | src/encoding/base64/base64.go | 14 |
1 files changed, 12 insertions, 2 deletions
diff --git a/src/encoding/base64/base64.go b/src/encoding/base64/base64.go index 802ef14c38..9445cbd4ef 100644 --- a/src/encoding/base64/base64.go +++ b/src/encoding/base64/base64.go @@ -411,7 +411,13 @@ func (enc *Encoding) decodeQuantum(dst, src []byte, si int) (nsi, n int, err err // 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 @@ -643,7 +649,11 @@ 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 base64-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 { // Unpadded data may end with partial block of 2-3 characters. return n/4*3 + n%4*6/8 } |