Adding upstream version 1.22.1.upstream/1.22.1

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

3 files changed, 1518 insertions, 0 deletions

diff --git a/src/encoding/base32/base32.go b/src/encoding/base32/base32.go
new file mode 100644
index 0000000..4a61199
--- /dev/null
+++ b/src/encoding/base32/base32.go
@@ -0,0 +1,583 @@
+// Copyright 2011 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 base32 implements base32 encoding as specified by RFC 4648.
+package base32
+
+import (
+	"io"
+	"slices"
+	"strconv"
+)
+
+/*
+ * Encodings
+ */
+
+// An Encoding is a radix 32 encoding/decoding scheme, defined by a
+// 32-character alphabet. The most common is the "base32" encoding
+// introduced for SASL GSSAPI and standardized in RFC 4648.
+// The alternate "base32hex" encoding is used in DNSSEC.
+type Encoding struct {
+	encode    [32]byte   // mapping of symbol index to symbol byte value
+	decodeMap [256]uint8 // mapping of symbol byte value to symbol index
+	padChar   rune
+}
+
+const (
+	StdPadding rune = '=' // Standard padding character
+	NoPadding  rune = -1  // No padding
+)
+
+const (
+	decodeMapInitialize = "" +
+		"\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff" +
+		"\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff" +
+		"\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff" +
+		"\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff" +
+		"\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff" +
+		"\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff" +
+		"\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff" +
+		"\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff" +
+		"\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff" +
+		"\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff" +
+		"\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff" +
+		"\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff" +
+		"\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff" +
+		"\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff" +
+		"\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff" +
+		"\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff"
+	invalidIndex = '\xff'
+)
+
+// NewEncoding returns a new padded Encoding defined by the given alphabet,
+// which must be a 32-byte string that contains unique byte values and
+// does not contain the padding character or CR / LF ('\r', '\n').
+// The alphabet is treated as a sequence of byte values
+// without any special treatment for multi-byte UTF-8.
+// The resulting Encoding uses the default padding character ('='),
+// which may be changed or disabled via [Encoding.WithPadding].
+func NewEncoding(encoder string) *Encoding {
+	if len(encoder) != 32 {
+		panic("encoding alphabet is not 32-bytes long")
+	}
+
+	e := new(Encoding)
+	e.padChar = StdPadding
+	copy(e.encode[:], encoder)
+	copy(e.decodeMap[:], decodeMapInitialize)
+
+	for i := 0; i < len(encoder); i++ {
+		// Note: While we document that the alphabet cannot contain
+		// the padding character, we do not enforce it since we do not know
+		// if the caller intends to switch the padding from StdPadding later.
+		switch {
+		case encoder[i] == '\n' || encoder[i] == '\r':
+			panic("encoding alphabet contains newline character")
+		case e.decodeMap[encoder[i]] != invalidIndex:
+			panic("encoding alphabet includes duplicate symbols")
+		}
+		e.decodeMap[encoder[i]] = uint8(i)
+	}
+	return e
+}
+
+// StdEncoding is the standard base32 encoding, as defined in RFC 4648.
+var StdEncoding = NewEncoding("ABCDEFGHIJKLMNOPQRSTUVWXYZ234567")
+
+// HexEncoding is the “Extended Hex Alphabet” defined in RFC 4648.
+// It is typically used in DNS.
+var HexEncoding = NewEncoding("0123456789ABCDEFGHIJKLMNOPQRSTUV")
+
+// WithPadding creates a new encoding identical to enc except
+// with a specified padding character, or NoPadding to disable padding.
+// The padding character must not be '\r' or '\n',
+// must not be contained in the encoding's alphabet,
+// must not be negative, and must be a rune equal or below '\xff'.
+// Padding characters above '\x7f' are encoded as their exact byte value
+// rather than using the UTF-8 representation of the codepoint.
+func (enc Encoding) WithPadding(padding rune) *Encoding {
+	switch {
+	case padding < NoPadding || padding == '\r' || padding == '\n' || padding > 0xff:
+		panic("invalid padding")
+	case padding != NoPadding && enc.decodeMap[byte(padding)] != invalidIndex:
+		panic("padding contained in alphabet")
+	}
+	enc.padChar = padding
+	return &enc
+}
+
+/*
+ * Encoder
+ */
+
+// Encode encodes src using the encoding enc,
+// writing [Encoding.EncodedLen](len(src)) bytes to dst.
+//
+// The encoding pads the output to a multiple of 8 bytes,
+// so Encode is not appropriate for use on individual blocks
+// of a large data stream. Use [NewEncoder] instead.
+func (enc *Encoding) Encode(dst, src []byte) {
+	if len(src) == 0 {
+		return
+	}
+	// enc is a pointer receiver, so the use of enc.encode within the hot
+	// loop below means a nil check at every operation. Lift that nil check
+	// outside of the loop to speed up the encoder.
+	_ = enc.encode
+
+	di, si := 0, 0
+	n := (len(src) / 5) * 5
+	for si < n {
+		// Combining two 32 bit loads allows the same code to be used
+		// for 32 and 64 bit platforms.
+		hi := uint32(src[si+0])<<24 | uint32(src[si+1])<<16 | uint32(src[si+2])<<8 | uint32(src[si+3])
+		lo := hi<<8 | uint32(src[si+4])
+
+		dst[di+0] = enc.encode[(hi>>27)&0x1F]
+		dst[di+1] = enc.encode[(hi>>22)&0x1F]
+		dst[di+2] = enc.encode[(hi>>17)&0x1F]
+		dst[di+3] = enc.encode[(hi>>12)&0x1F]
+		dst[di+4] = enc.encode[(hi>>7)&0x1F]
+		dst[di+5] = enc.encode[(hi>>2)&0x1F]
+		dst[di+6] = enc.encode[(lo>>5)&0x1F]
+		dst[di+7] = enc.encode[(lo)&0x1F]
+
+		si += 5
+		di += 8
+	}
+
+	// Add the remaining small block
+	remain := len(src) - si
+	if remain == 0 {
+		return
+	}
+
+	// Encode the remaining bytes in reverse order.
+	val := uint32(0)
+	switch remain {
+	case 4:
+		val |= uint32(src[si+3])
+		dst[di+6] = enc.encode[val<<3&0x1F]
+		dst[di+5] = enc.encode[val>>2&0x1F]
+		fallthrough
+	case 3:
+		val |= uint32(src[si+2]) << 8
+		dst[di+4] = enc.encode[val>>7&0x1F]
+		fallthrough
+	case 2:
+		val |= uint32(src[si+1]) << 16
+		dst[di+3] = enc.encode[val>>12&0x1F]
+		dst[di+2] = enc.encode[val>>17&0x1F]
+		fallthrough
+	case 1:
+		val |= uint32(src[si+0]) << 24
+		dst[di+1] = enc.encode[val>>22&0x1F]
+		dst[di+0] = enc.encode[val>>27&0x1F]
+	}
+
+	// Pad the final quantum
+	if enc.padChar != NoPadding {
+		nPad := (remain * 8 / 5) + 1
+		for i := nPad; i < 8; i++ {
+			dst[di+i] = byte(enc.padChar)
+		}
+	}
+}
+
+// AppendEncode appends the base32 encoded src to dst
+// and returns the extended buffer.
+func (enc *Encoding) AppendEncode(dst, src []byte) []byte {
+	n := enc.EncodedLen(len(src))
+	dst = slices.Grow(dst, n)
+	enc.Encode(dst[len(dst):][:n], src)
+	return dst[:len(dst)+n]
+}
+
+// EncodeToString returns the base32 encoding of src.
+func (enc *Encoding) EncodeToString(src []byte) string {
+	buf := make([]byte, enc.EncodedLen(len(src)))
+	enc.Encode(buf, src)
+	return string(buf)
+}
+
+type encoder struct {
+	err  error
+	enc  *Encoding
+	w    io.Writer
+	buf  [5]byte    // buffered data waiting to be encoded
+	nbuf int        // number of bytes in buf
+	out  [1024]byte // output buffer
+}
+
+func (e *encoder) Write(p []byte) (n int, err error) {
+	if e.err != nil {
+		return 0, e.err
+	}
+
+	// Leading fringe.
+	if e.nbuf > 0 {
+		var i int
+		for i = 0; i < len(p) && e.nbuf < 5; i++ {
+			e.buf[e.nbuf] = p[i]
+			e.nbuf++
+		}
+		n += i
+		p = p[i:]
+		if e.nbuf < 5 {
+			return
+		}
+		e.enc.Encode(e.out[0:], e.buf[0:])
+		if _, e.err = e.w.Write(e.out[0:8]); e.err != nil {
+			return n, e.err
+		}
+		e.nbuf = 0
+	}
+
+	// Large interior chunks.
+	for len(p) >= 5 {
+		nn := len(e.out) / 8 * 5
+		if nn > len(p) {
+			nn = len(p)
+			nn -= nn % 5
+		}
+		e.enc.Encode(e.out[0:], p[0:nn])
+		if _, e.err = e.w.Write(e.out[0 : nn/5*8]); e.err != nil {
+			return n, e.err
+		}
+		n += nn
+		p = p[nn:]
+	}
+
+	// Trailing fringe.
+	copy(e.buf[:], p)
+	e.nbuf = len(p)
+	n += len(p)
+	return
+}
+
+// Close flushes any pending output from the encoder.
+// It is an error to call Write after calling Close.
+func (e *encoder) Close() error {
+	// If there's anything left in the buffer, flush it out
+	if e.err == nil && e.nbuf > 0 {
+		e.enc.Encode(e.out[0:], e.buf[0:e.nbuf])
+		encodedLen := e.enc.EncodedLen(e.nbuf)
+		e.nbuf = 0
+		_, e.err = e.w.Write(e.out[0:encodedLen])
+	}
+	return e.err
+}
+
+// NewEncoder returns a new base32 stream encoder. Data written to
+// the returned writer will be encoded using enc and then written to w.
+// Base32 encodings operate in 5-byte blocks; when finished
+// writing, the caller must Close the returned encoder to flush any
+// partially written blocks.
+func NewEncoder(enc *Encoding, w io.Writer) io.WriteCloser {
+	return &encoder{enc: enc, w: w}
+}
+
+// EncodedLen returns the length in bytes of the base32 encoding
+// of an input buffer of length n.
+func (enc *Encoding) EncodedLen(n int) int {
+	if enc.padChar == NoPadding {
+		return n/5*8 + (n%5*8+4)/5
+	}
+	return (n + 4) / 5 * 8
+}
+
+/*
+ * Decoder
+ */
+
+type CorruptInputError int64
+
+func (e CorruptInputError) Error() string {
+	return "illegal base32 data at input byte " + strconv.FormatInt(int64(e), 10)
+}
+
+// decode is like Decode but returns an additional 'end' value, which
+// indicates if end-of-message padding was encountered and thus any
+// additional data is an error. This method assumes that src has been
+// stripped of all supported whitespace ('\r' and '\n').
+func (enc *Encoding) decode(dst, src []byte) (n int, end bool, err error) {
+	// Lift the nil check outside of the loop.
+	_ = enc.decodeMap
+
+	dsti := 0
+	olen := len(src)
+
+	for len(src) > 0 && !end {
+		// Decode quantum using the base32 alphabet
+		var dbuf [8]byte
+		dlen := 8
+
+		for j := 0; j < 8; {
+
+			if len(src) == 0 {
+				if enc.padChar != NoPadding {
+					// We have reached the end and are missing padding
+					return n, false, CorruptInputError(olen - len(src) - j)
+				}
+				// We have reached the end and are not expecting any padding
+				dlen, end = j, true
+				break
+			}
+			in := src[0]
+			src = src[1:]
+			if in == byte(enc.padChar) && j >= 2 && len(src) < 8 {
+				// We've reached the end and there's padding
+				if len(src)+j < 8-1 {
+					// not enough padding
+					return n, false, CorruptInputError(olen)
+				}
+				for k := 0; k < 8-1-j; k++ {
+					if len(src) > k && src[k] != byte(enc.padChar) {
+						// incorrect padding
+						return n, false, CorruptInputError(olen - len(src) + k - 1)
+					}
+				}
+				dlen, end = j, true
+				// 7, 5 and 2 are not valid padding lengths, and so 1, 3 and 6 are not
+				// valid dlen values. See RFC 4648 Section 6 "Base 32 Encoding" listing
+				// the five valid padding lengths, and Section 9 "Illustrations and
+				// Examples" for an illustration for how the 1st, 3rd and 6th base32
+				// src bytes do not yield enough information to decode a dst byte.
+				if dlen == 1 || dlen == 3 || dlen == 6 {
+					return n, false, CorruptInputError(olen - len(src) - 1)
+				}
+				break
+			}
+			dbuf[j] = enc.decodeMap[in]
+			if dbuf[j] == 0xFF {
+				return n, false, CorruptInputError(olen - len(src) - 1)
+			}
+			j++
+		}
+
+		// Pack 8x 5-bit source blocks into 5 byte destination
+		// quantum
+		switch dlen {
+		case 8:
+			dst[dsti+4] = dbuf[6]<<5 | dbuf[7]
+			n++
+			fallthrough
+		case 7:
+			dst[dsti+3] = dbuf[4]<<7 | dbuf[5]<<2 | dbuf[6]>>3
+			n++
+			fallthrough
+		case 5:
+			dst[dsti+2] = dbuf[3]<<4 | dbuf[4]>>1
+			n++
+			fallthrough
+		case 4:
+			dst[dsti+1] = dbuf[1]<<6 | dbuf[2]<<1 | dbuf[3]>>4
+			n++
+			fallthrough
+		case 2:
+			dst[dsti+0] = dbuf[0]<<3 | dbuf[1]>>2
+			n++
+		}
+		dsti += 5
+	}
+	return n, end, nil
+}
+
+// Decode decodes src using the encoding enc. It writes at most
+// [Encoding.DecodedLen](len(src)) bytes to dst and returns the number of bytes
+// written. If src contains invalid base32 data, it will return the
+// number of bytes successfully written and [CorruptInputError].
+// Newline characters (\r and \n) are ignored.
+func (enc *Encoding) Decode(dst, src []byte) (n int, err error) {
+	buf := make([]byte, len(src))
+	l := stripNewlines(buf, src)
+	n, _, err = enc.decode(dst, buf[:l])
+	return
+}
+
+// AppendDecode appends the base32 decoded src to dst
+// 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) {
+	// 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
+}
+
+// DecodeString returns the bytes represented by the base32 string s.
+func (enc *Encoding) DecodeString(s string) ([]byte, error) {
+	buf := []byte(s)
+	l := stripNewlines(buf, buf)
+	n, _, err := enc.decode(buf, buf[:l])
+	return buf[:n], err
+}
+
+type decoder struct {
+	err    error
+	enc    *Encoding
+	r      io.Reader
+	end    bool       // saw end of message
+	buf    [1024]byte // leftover input
+	nbuf   int
+	out    []byte // leftover decoded output
+	outbuf [1024 / 8 * 5]byte
+}
+
+func readEncodedData(r io.Reader, buf []byte, min int, expectsPadding bool) (n int, err error) {
+	for n < min && err == nil {
+		var nn int
+		nn, err = r.Read(buf[n:])
+		n += nn
+	}
+	// data was read, less than min bytes could be read
+	if n < min && n > 0 && err == io.EOF {
+		err = io.ErrUnexpectedEOF
+	}
+	// no data was read, the buffer already contains some data
+	// when padding is disabled this is not an error, as the message can be of
+	// any length
+	if expectsPadding && min < 8 && n == 0 && err == io.EOF {
+		err = io.ErrUnexpectedEOF
+	}
+	return
+}
+
+func (d *decoder) Read(p []byte) (n int, err error) {
+	// Use leftover decoded output from last read.
+	if len(d.out) > 0 {
+		n = copy(p, d.out)
+		d.out = d.out[n:]
+		if len(d.out) == 0 {
+			return n, d.err
+		}
+		return n, nil
+	}
+
+	if d.err != nil {
+		return 0, d.err
+	}
+
+	// Read a chunk.
+	nn := len(p) / 5 * 8
+	if nn < 8 {
+		nn = 8
+	}
+	if nn > len(d.buf) {
+		nn = len(d.buf)
+	}
+
+	// Minimum amount of bytes that needs to be read each cycle
+	var min int
+	var expectsPadding bool
+	if d.enc.padChar == NoPadding {
+		min = 1
+		expectsPadding = false
+	} else {
+		min = 8 - d.nbuf
+		expectsPadding = true
+	}
+
+	nn, d.err = readEncodedData(d.r, d.buf[d.nbuf:nn], min, expectsPadding)
+	d.nbuf += nn
+	if d.nbuf < min {
+		return 0, d.err
+	}
+	if nn > 0 && d.end {
+		return 0, CorruptInputError(0)
+	}
+
+	// Decode chunk into p, or d.out and then p if p is too small.
+	var nr int
+	if d.enc.padChar == NoPadding {
+		nr = d.nbuf
+	} else {
+		nr = d.nbuf / 8 * 8
+	}
+	nw := d.enc.DecodedLen(d.nbuf)
+
+	if nw > len(p) {
+		nw, d.end, err = d.enc.decode(d.outbuf[0:], d.buf[0:nr])
+		d.out = d.outbuf[0:nw]
+		n = copy(p, d.out)
+		d.out = d.out[n:]
+	} else {
+		n, d.end, err = d.enc.decode(p, d.buf[0:nr])
+	}
+	d.nbuf -= nr
+	for i := 0; i < d.nbuf; i++ {
+		d.buf[i] = d.buf[i+nr]
+	}
+
+	if err != nil && (d.err == nil || d.err == io.EOF) {
+		d.err = err
+	}
+
+	if len(d.out) > 0 {
+		// We cannot return all the decoded bytes to the caller in this
+		// invocation of Read, so we return a nil error to ensure that Read
+		// will be called again.  The error stored in d.err, if any, will be
+		// returned with the last set of decoded bytes.
+		return n, nil
+	}
+
+	return n, d.err
+}
+
+type newlineFilteringReader struct {
+	wrapped io.Reader
+}
+
+// stripNewlines removes newline characters and returns the number
+// of non-newline characters copied to dst.
+func stripNewlines(dst, src []byte) int {
+	offset := 0
+	for _, b := range src {
+		if b == '\r' || b == '\n' {
+			continue
+		}
+		dst[offset] = b
+		offset++
+	}
+	return offset
+}
+
+func (r *newlineFilteringReader) Read(p []byte) (int, error) {
+	n, err := r.wrapped.Read(p)
+	for n > 0 {
+		s := p[0:n]
+		offset := stripNewlines(s, s)
+		if err != nil || offset > 0 {
+			return offset, err
+		}
+		// Previous buffer entirely whitespace, read again
+		n, err = r.wrapped.Read(p)
+	}
+	return n, err
+}
+
+// NewDecoder constructs a new base32 stream decoder.
+func NewDecoder(enc *Encoding, r io.Reader) io.Reader {
+	return &decoder{enc: enc, r: &newlineFilteringReader{r}}
+}
+
+// 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 {
+	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
+}
diff --git a/src/encoding/base32/base32_test.go b/src/encoding/base32/base32_test.go
new file mode 100644
index 0000000..33638ad
--- /dev/null
+++ b/src/encoding/base32/base32_test.go
@@ -0,0 +1,867 @@
+// Copyright 2009 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 base32
+
+import (
+	"bytes"
+	"errors"
+	"io"
+	"math"
+	"strconv"
+	"strings"
+	"testing"
+)
+
+type testpair struct {
+	decoded, encoded string
+}
+
+var pairs = []testpair{
+	// RFC 4648 examples
+	{"", ""},
+	{"f", "MY======"},
+	{"fo", "MZXQ===="},
+	{"foo", "MZXW6==="},
+	{"foob", "MZXW6YQ="},
+	{"fooba", "MZXW6YTB"},
+	{"foobar", "MZXW6YTBOI======"},
+
+	// Wikipedia examples, converted to base32
+	{"sure.", "ON2XEZJO"},
+	{"sure", "ON2XEZI="},
+	{"sur", "ON2XE==="},
+	{"su", "ON2Q===="},
+	{"leasure.", "NRSWC43VOJSS4==="},
+	{"easure.", "MVQXG5LSMUXA===="},
+	{"asure.", "MFZXK4TFFY======"},
+	{"sure.", "ON2XEZJO"},
+}
+
+var bigtest = testpair{
+	"Twas brillig, and the slithy toves",
+	"KR3WC4ZAMJZGS3DMNFTSYIDBNZSCA5DIMUQHG3DJORUHSIDUN53GK4Y=",
+}
+
+func testEqual(t *testing.T, msg string, args ...any) bool {
+	t.Helper()
+	if args[len(args)-2] != args[len(args)-1] {
+		t.Errorf(msg, args...)
+		return false
+	}
+	return true
+}
+
+func TestEncode(t *testing.T) {
+	for _, p := range pairs {
+		got := StdEncoding.EncodeToString([]byte(p.decoded))
+		testEqual(t, "Encode(%q) = %q, want %q", p.decoded, got, p.encoded)
+		dst := StdEncoding.AppendEncode([]byte("lead"), []byte(p.decoded))
+		testEqual(t, `AppendEncode("lead", %q) = %q, want %q`, p.decoded, string(dst), "lead"+p.encoded)
+	}
+}
+
+func TestEncoder(t *testing.T) {
+	for _, p := range pairs {
+		bb := &strings.Builder{}
+		encoder := NewEncoder(StdEncoding, bb)
+		encoder.Write([]byte(p.decoded))
+		encoder.Close()
+		testEqual(t, "Encode(%q) = %q, want %q", p.decoded, bb.String(), p.encoded)
+	}
+}
+
+func TestEncoderBuffering(t *testing.T) {
+	input := []byte(bigtest.decoded)
+	for bs := 1; bs <= 12; bs++ {
+		bb := &strings.Builder{}
+		encoder := NewEncoder(StdEncoding, bb)
+		for pos := 0; pos < len(input); pos += bs {
+			end := pos + bs
+			if end > len(input) {
+				end = len(input)
+			}
+			n, err := encoder.Write(input[pos:end])
+			testEqual(t, "Write(%q) gave error %v, want %v", input[pos:end], err, error(nil))
+			testEqual(t, "Write(%q) gave length %v, want %v", input[pos:end], n, end-pos)
+		}
+		err := encoder.Close()
+		testEqual(t, "Close gave error %v, want %v", err, error(nil))
+		testEqual(t, "Encoding/%d of %q = %q, want %q", bs, bigtest.decoded, bb.String(), bigtest.encoded)
+	}
+}
+
+func TestDecode(t *testing.T) {
+	for _, p := range pairs {
+		dbuf := make([]byte, StdEncoding.DecodedLen(len(p.encoded)))
+		count, end, err := StdEncoding.decode(dbuf, []byte(p.encoded))
+		testEqual(t, "Decode(%q) = error %v, want %v", p.encoded, err, error(nil))
+		testEqual(t, "Decode(%q) = length %v, want %v", p.encoded, count, len(p.decoded))
+		if len(p.encoded) > 0 {
+			testEqual(t, "Decode(%q) = end %v, want %v", p.encoded, end, (p.encoded[len(p.encoded)-1] == '='))
+		}
+		testEqual(t, "Decode(%q) = %q, want %q", p.encoded, string(dbuf[0:count]), p.decoded)
+
+		dbuf, err = StdEncoding.DecodeString(p.encoded)
+		testEqual(t, "DecodeString(%q) = error %v, want %v", p.encoded, err, error(nil))
+		testEqual(t, "DecodeString(%q) = %q, want %q", p.encoded, string(dbuf), p.decoded)
+
+		dst, err := StdEncoding.AppendDecode([]byte("lead"), []byte(p.encoded))
+		testEqual(t, "AppendDecode(%q) = error %v, want %v", p.encoded, err, error(nil))
+		testEqual(t, `AppendDecode("lead", %q) = %q, want %q`, p.encoded, string(dst), "lead"+p.decoded)
+
+		dst2, err := StdEncoding.AppendDecode(dst[:0:len(p.decoded)], []byte(p.encoded))
+		testEqual(t, "AppendDecode(%q) = error %v, want %v", p.encoded, err, error(nil))
+		testEqual(t, `AppendDecode("", %q) = %q, want %q`, p.encoded, string(dst2), p.decoded)
+		if len(dst) > 0 && len(dst2) > 0 && &dst[0] != &dst2[0] {
+			t.Errorf("unexpected capacity growth: got %d, want %d", cap(dst2), cap(dst))
+		}
+	}
+}
+
+func TestDecoder(t *testing.T) {
+	for _, p := range pairs {
+		decoder := NewDecoder(StdEncoding, strings.NewReader(p.encoded))
+		dbuf := make([]byte, StdEncoding.DecodedLen(len(p.encoded)))
+		count, err := decoder.Read(dbuf)
+		if err != nil && err != io.EOF {
+			t.Fatal("Read failed", err)
+		}
+		testEqual(t, "Read from %q = length %v, want %v", p.encoded, count, len(p.decoded))
+		testEqual(t, "Decoding of %q = %q, want %q", p.encoded, string(dbuf[0:count]), p.decoded)
+		if err != io.EOF {
+			_, err = decoder.Read(dbuf)
+		}
+		testEqual(t, "Read from %q = %v, want %v", p.encoded, err, io.EOF)
+	}
+}
+
+type badReader struct {
+	data   []byte
+	errs   []error
+	called int
+	limit  int
+}
+
+// Populates p with data, returns a count of the bytes written and an
+// error.  The error returned is taken from badReader.errs, with each
+// invocation of Read returning the next error in this slice, or io.EOF,
+// if all errors from the slice have already been returned.  The
+// number of bytes returned is determined by the size of the input buffer
+// the test passes to decoder.Read and will be a multiple of 8, unless
+// badReader.limit is non zero.
+func (b *badReader) Read(p []byte) (int, error) {
+	lim := len(p)
+	if b.limit != 0 && b.limit < lim {
+		lim = b.limit
+	}
+	if len(b.data) < lim {
+		lim = len(b.data)
+	}
+	for i := range p[:lim] {
+		p[i] = b.data[i]
+	}
+	b.data = b.data[lim:]
+	err := io.EOF
+	if b.called < len(b.errs) {
+		err = b.errs[b.called]
+	}
+	b.called++
+	return lim, err
+}
+
+// TestIssue20044 tests that decoder.Read behaves correctly when the caller
+// supplied reader returns an error.
+func TestIssue20044(t *testing.T) {
+	badErr := errors.New("bad reader error")
+	testCases := []struct {
+		r       badReader
+		res     string
+		err     error
+		dbuflen int
+	}{
+		// Check valid input data accompanied by an error is processed and the error is propagated.
+		{r: badReader{data: []byte("MY======"), errs: []error{badErr}},
+			res: "f", err: badErr},
+		// Check a read error accompanied by input data consisting of newlines only is propagated.
+		{r: badReader{data: []byte("\n\n\n\n\n\n\n\n"), errs: []error{badErr, nil}},
+			res: "", err: badErr},
+		// Reader will be called twice.  The first time it will return 8 newline characters.  The
+		// second time valid base32 encoded data and an error.  The data should be decoded
+		// correctly and the error should be propagated.
+		{r: badReader{data: []byte("\n\n\n\n\n\n\n\nMY======"), errs: []error{nil, badErr}},
+			res: "f", err: badErr, dbuflen: 8},
+		// Reader returns invalid input data (too short) and an error.  Verify the reader
+		// error is returned.
+		{r: badReader{data: []byte("MY====="), errs: []error{badErr}},
+			res: "", err: badErr},
+		// Reader returns invalid input data (too short) but no error.  Verify io.ErrUnexpectedEOF
+		// is returned.
+		{r: badReader{data: []byte("MY====="), errs: []error{nil}},
+			res: "", err: io.ErrUnexpectedEOF},
+		// Reader returns invalid input data and an error.  Verify the reader and not the
+		// decoder error is returned.
+		{r: badReader{data: []byte("Ma======"), errs: []error{badErr}},
+			res: "", err: badErr},
+		// Reader returns valid data and io.EOF.  Check data is decoded and io.EOF is propagated.
+		{r: badReader{data: []byte("MZXW6YTB"), errs: []error{io.EOF}},
+			res: "fooba", err: io.EOF},
+		// Check errors are properly reported when decoder.Read is called multiple times.
+		// decoder.Read will be called 8 times, badReader.Read will be called twice, returning
+		// valid data both times but an error on the second call.
+		{r: badReader{data: []byte("NRSWC43VOJSS4==="), errs: []error{nil, badErr}},
+			res: "leasure.", err: badErr, dbuflen: 1},
+		// Check io.EOF is properly reported when decoder.Read is called multiple times.
+		// decoder.Read will be called 8 times, badReader.Read will be called twice, returning
+		// valid data both times but io.EOF on the second call.
+		{r: badReader{data: []byte("NRSWC43VOJSS4==="), errs: []error{nil, io.EOF}},
+			res: "leasure.", err: io.EOF, dbuflen: 1},
+		// The following two test cases check that errors are propagated correctly when more than
+		// 8 bytes are read at a time.
+		{r: badReader{data: []byte("NRSWC43VOJSS4==="), errs: []error{io.EOF}},
+			res: "leasure.", err: io.EOF, dbuflen: 11},
+		{r: badReader{data: []byte("NRSWC43VOJSS4==="), errs: []error{badErr}},
+			res: "leasure.", err: badErr, dbuflen: 11},
+		// Check that errors are correctly propagated when the reader returns valid bytes in
+		// groups that are not divisible by 8.  The first read will return 11 bytes and no
+		// error.  The second will return 7 and an error.  The data should be decoded correctly
+		// and the error should be propagated.
+		{r: badReader{data: []byte("NRSWC43VOJSS4==="), errs: []error{nil, badErr}, limit: 11},
+			res: "leasure.", err: badErr},
+	}
+
+	for _, tc := range testCases {
+		input := tc.r.data
+		decoder := NewDecoder(StdEncoding, &tc.r)
+		var dbuflen int
+		if tc.dbuflen > 0 {
+			dbuflen = tc.dbuflen
+		} else {
+			dbuflen = StdEncoding.DecodedLen(len(input))
+		}
+		dbuf := make([]byte, dbuflen)
+		var err error
+		var res []byte
+		for err == nil {
+			var n int
+			n, err = decoder.Read(dbuf)
+			if n > 0 {
+				res = append(res, dbuf[:n]...)
+			}
+		}
+
+		testEqual(t, "Decoding of %q = %q, want %q", string(input), string(res), tc.res)
+		testEqual(t, "Decoding of %q err = %v, expected %v", string(input), err, tc.err)
+	}
+}
+
+// TestDecoderError verifies decode errors are propagated when there are no read
+// errors.
+func TestDecoderError(t *testing.T) {
+	for _, readErr := range []error{io.EOF, nil} {
+		input := "MZXW6YTb"
+		dbuf := make([]byte, StdEncoding.DecodedLen(len(input)))
+		br := badReader{data: []byte(input), errs: []error{readErr}}
+		decoder := NewDecoder(StdEncoding, &br)
+		n, err := decoder.Read(dbuf)
+		testEqual(t, "Read after EOF, n = %d, expected %d", n, 0)
+		if _, ok := err.(CorruptInputError); !ok {
+			t.Errorf("Corrupt input error expected.  Found %T", err)
+		}
+	}
+}
+
+// TestReaderEOF ensures decoder.Read behaves correctly when input data is
+// exhausted.
+func TestReaderEOF(t *testing.T) {
+	for _, readErr := range []error{io.EOF, nil} {
+		input := "MZXW6YTB"
+		br := badReader{data: []byte(input), errs: []error{nil, readErr}}
+		decoder := NewDecoder(StdEncoding, &br)
+		dbuf := make([]byte, StdEncoding.DecodedLen(len(input)))
+		n, err := decoder.Read(dbuf)
+		testEqual(t, "Decoding of %q err = %v, expected %v", input, err, error(nil))
+		n, err = decoder.Read(dbuf)
+		testEqual(t, "Read after EOF, n = %d, expected %d", n, 0)
+		testEqual(t, "Read after EOF, err = %v, expected %v", err, io.EOF)
+		n, err = decoder.Read(dbuf)
+		testEqual(t, "Read after EOF, n = %d, expected %d", n, 0)
+		testEqual(t, "Read after EOF, err = %v, expected %v", err, io.EOF)
+	}
+}
+
+func TestDecoderBuffering(t *testing.T) {
+	for bs := 1; bs <= 12; bs++ {
+		decoder := NewDecoder(StdEncoding, strings.NewReader(bigtest.encoded))
+		buf := make([]byte, len(bigtest.decoded)+12)
+		var total int
+		var n int
+		var err error
+		for total = 0; total < len(bigtest.decoded) && err == nil; {
+			n, err = decoder.Read(buf[total : total+bs])
+			total += n
+		}
+		if err != nil && err != io.EOF {
+			t.Errorf("Read from %q at pos %d = %d, unexpected error %v", bigtest.encoded, total, n, err)
+		}
+		testEqual(t, "Decoding/%d of %q = %q, want %q", bs, bigtest.encoded, string(buf[0:total]), bigtest.decoded)
+	}
+}
+
+func TestDecodeCorrupt(t *testing.T) {
+	testCases := []struct {
+		input  string
+		offset int // -1 means no corruption.
+	}{
+		{"", -1},
+		{"!!!!", 0},
+		{"x===", 0},
+		{"AA=A====", 2},
+		{"AAA=AAAA", 3},
+		{"MMMMMMMMM", 8},
+		{"MMMMMM", 0},
+		{"A=", 1},
+		{"AA=", 3},
+		{"AA==", 4},
+		{"AA===", 5},
+		{"AAAA=", 5},
+		{"AAAA==", 6},
+		{"AAAAA=", 6},
+		{"AAAAA==", 7},
+		{"A=======", 1},
+		{"AA======", -1},
+		{"AAA=====", 3},
+		{"AAAA====", -1},
+		{"AAAAA===", -1},
+		{"AAAAAA==", 6},
+		{"AAAAAAA=", -1},
+		{"AAAAAAAA", -1},
+	}
+	for _, tc := range testCases {
+		dbuf := make([]byte, StdEncoding.DecodedLen(len(tc.input)))
+		_, err := StdEncoding.Decode(dbuf, []byte(tc.input))
+		if tc.offset == -1 {
+			if err != nil {
+				t.Error("Decoder wrongly detected corruption in", tc.input)
+			}
+			continue
+		}
+		switch err := err.(type) {
+		case CorruptInputError:
+			testEqual(t, "Corruption in %q at offset %v, want %v", tc.input, int(err), tc.offset)
+		default:
+			t.Error("Decoder failed to detect corruption in", tc)
+		}
+	}
+}
+
+func TestBig(t *testing.T) {
+	n := 3*1000 + 1
+	raw := make([]byte, n)
+	const alpha = "0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ"
+	for i := 0; i < n; i++ {
+		raw[i] = alpha[i%len(alpha)]
+	}
+	encoded := new(bytes.Buffer)
+	w := NewEncoder(StdEncoding, encoded)
+	nn, err := w.Write(raw)
+	if nn != n || err != nil {
+		t.Fatalf("Encoder.Write(raw) = %d, %v want %d, nil", nn, err, n)
+	}
+	err = w.Close()
+	if err != nil {
+		t.Fatalf("Encoder.Close() = %v want nil", err)
+	}
+	decoded, err := io.ReadAll(NewDecoder(StdEncoding, encoded))
+	if err != nil {
+		t.Fatalf("io.ReadAll(NewDecoder(...)): %v", err)
+	}
+
+	if !bytes.Equal(raw, decoded) {
+		var i int
+		for i = 0; i < len(decoded) && i < len(raw); i++ {
+			if decoded[i] != raw[i] {
+				break
+			}
+		}
+		t.Errorf("Decode(Encode(%d-byte string)) failed at offset %d", n, i)
+	}
+}
+
+func testStringEncoding(t *testing.T, expected string, examples []string) {
+	for _, e := range examples {
+		buf, err := StdEncoding.DecodeString(e)
+		if err != nil {
+			t.Errorf("Decode(%q) failed: %v", e, err)
+			continue
+		}
+		if s := string(buf); s != expected {
+			t.Errorf("Decode(%q) = %q, want %q", e, s, expected)
+		}
+	}
+}
+
+func TestNewLineCharacters(t *testing.T) {
+	// Each of these should decode to the string "sure", without errors.
+	examples := []string{
+		"ON2XEZI=",
+		"ON2XEZI=\r",
+		"ON2XEZI=\n",
+		"ON2XEZI=\r\n",
+		"ON2XEZ\r\nI=",
+		"ON2X\rEZ\nI=",
+		"ON2X\nEZ\rI=",
+		"ON2XEZ\nI=",
+		"ON2XEZI\n=",
+	}
+	testStringEncoding(t, "sure", examples)
+
+	// Each of these should decode to the string "foobar", without errors.
+	examples = []string{
+		"MZXW6YTBOI======",
+		"MZXW6YTBOI=\r\n=====",
+	}
+	testStringEncoding(t, "foobar", examples)
+}
+
+func TestDecoderIssue4779(t *testing.T) {
+	encoded := `JRXXEZLNEBUXA43VNUQGI33MN5ZCA43JOQQGC3LFOQWCAY3PNZZWKY3UMV2HK4
+RAMFSGS4DJONUWG2LOM4QGK3DJOQWCA43FMQQGI3YKMVUXK43NN5SCA5DFNVYG64RANFXGG2LENFSH
+K3TUEB2XIIDMMFRG64TFEBSXIIDEN5WG64TFEBWWCZ3OMEQGC3DJOF2WCLRAKV2CAZLONFWQUYLEEB
+WWS3TJNUQHMZLONFQW2LBAOF2WS4ZANZXXG5DSOVSCAZLYMVZGG2LUMF2GS33OEB2WY3DBNVRW6IDM
+MFRG64TJOMQG42LTNEQHK5AKMFWGS4LVNFYCAZLYEBSWCIDDN5WW233EN4QGG33OONSXC5LBOQXCAR
+DVNFZSAYLVORSSA2LSOVZGKIDEN5WG64RANFXAU4TFOBZGK2DFNZSGK4TJOQQGS3RAOZXWY5LQORQX
+IZJAOZSWY2LUEBSXG43FEBRWS3DMOVWSAZDPNRXXEZJAMV2SAZTVM5UWC5BANZ2WY3DBBJYGC4TJMF
+2HK4ROEBCXQY3FOB2GK5LSEBZWS3TUEBXWGY3BMVRWC5BAMN2XA2LEMF2GC5BANZXW4IDQOJXWSZDF
+NZ2CYIDTOVXHIIDJNYFGG5LMOBQSA4LVNEQG6ZTGNFRWSYJAMRSXGZLSOVXHIIDNN5WGY2LUEBQW42
+LNEBUWIIDFON2CA3DBMJXXE5LNFY==
+====`
+	encodedShort := strings.ReplaceAll(encoded, "\n", "")
+
+	dec := NewDecoder(StdEncoding, strings.NewReader(encoded))
+	res1, err := io.ReadAll(dec)
+	if err != nil {
+		t.Errorf("ReadAll failed: %v", err)
+	}
+
+	dec = NewDecoder(StdEncoding, strings.NewReader(encodedShort))
+	var res2 []byte
+	res2, err = io.ReadAll(dec)
+	if err != nil {
+		t.Errorf("ReadAll failed: %v", err)
+	}
+
+	if !bytes.Equal(res1, res2) {
+		t.Error("Decoded results not equal")
+	}
+}
+
+func BenchmarkEncode(b *testing.B) {
+	data := make([]byte, 8192)
+	buf := make([]byte, StdEncoding.EncodedLen(len(data)))
+	b.SetBytes(int64(len(data)))
+	for i := 0; i < b.N; i++ {
+		StdEncoding.Encode(buf, data)
+	}
+}
+
+func BenchmarkEncodeToString(b *testing.B) {
+	data := make([]byte, 8192)
+	b.SetBytes(int64(len(data)))
+	for i := 0; i < b.N; i++ {
+		StdEncoding.EncodeToString(data)
+	}
+}
+
+func BenchmarkDecode(b *testing.B) {
+	data := make([]byte, StdEncoding.EncodedLen(8192))
+	StdEncoding.Encode(data, make([]byte, 8192))
+	buf := make([]byte, 8192)
+	b.SetBytes(int64(len(data)))
+	for i := 0; i < b.N; i++ {
+		StdEncoding.Decode(buf, data)
+	}
+}
+func BenchmarkDecodeString(b *testing.B) {
+	data := StdEncoding.EncodeToString(make([]byte, 8192))
+	b.SetBytes(int64(len(data)))
+	for i := 0; i < b.N; i++ {
+		StdEncoding.DecodeString(data)
+	}
+}
+
+func TestWithCustomPadding(t *testing.T) {
+	for _, testcase := range pairs {
+		defaultPadding := StdEncoding.EncodeToString([]byte(testcase.decoded))
+		customPadding := StdEncoding.WithPadding('@').EncodeToString([]byte(testcase.decoded))
+		expected := strings.ReplaceAll(defaultPadding, "=", "@")
+
+		if expected != customPadding {
+			t.Errorf("Expected custom %s, got %s", expected, customPadding)
+		}
+		if testcase.encoded != defaultPadding {
+			t.Errorf("Expected %s, got %s", testcase.encoded, defaultPadding)
+		}
+	}
+}
+
+func TestWithoutPadding(t *testing.T) {
+	for _, testcase := range pairs {
+		defaultPadding := StdEncoding.EncodeToString([]byte(testcase.decoded))
+		customPadding := StdEncoding.WithPadding(NoPadding).EncodeToString([]byte(testcase.decoded))
+		expected := strings.TrimRight(defaultPadding, "=")
+
+		if expected != customPadding {
+			t.Errorf("Expected custom %s, got %s", expected, customPadding)
+		}
+		if testcase.encoded != defaultPadding {
+			t.Errorf("Expected %s, got %s", testcase.encoded, defaultPadding)
+		}
+	}
+}
+
+func TestDecodeWithPadding(t *testing.T) {
+	encodings := []*Encoding{
+		StdEncoding,
+		StdEncoding.WithPadding('-'),
+		StdEncoding.WithPadding(NoPadding),
+	}
+
+	for i, enc := range encodings {
+		for _, pair := range pairs {
+
+			input := pair.decoded
+			encoded := enc.EncodeToString([]byte(input))
+
+			decoded, err := enc.DecodeString(encoded)
+			if err != nil {
+				t.Errorf("DecodeString Error for encoding %d (%q): %v", i, input, err)
+			}
+
+			if input != string(decoded) {
+				t.Errorf("Unexpected result for encoding %d: got %q; want %q", i, decoded, input)
+			}
+		}
+	}
+}
+
+func TestDecodeWithWrongPadding(t *testing.T) {
+	encoded := StdEncoding.EncodeToString([]byte("foobar"))
+
+	_, err := StdEncoding.WithPadding('-').DecodeString(encoded)
+	if err == nil {
+		t.Error("expected error")
+	}
+
+	_, err = StdEncoding.WithPadding(NoPadding).DecodeString(encoded)
+	if err == nil {
+		t.Error("expected error")
+	}
+}
+
+func TestBufferedDecodingSameError(t *testing.T) {
+	testcases := []struct {
+		prefix            string
+		chunkCombinations [][]string
+		expected          error
+	}{
+		// NBSWY3DPO5XXE3DE == helloworld
+		// Test with "ZZ" as extra input
+		{"helloworld", [][]string{
+			{"NBSW", "Y3DP", "O5XX", "E3DE", "ZZ"},
+			{"NBSWY3DPO5XXE3DE", "ZZ"},
+			{"NBSWY3DPO5XXE3DEZZ"},
+			{"NBS", "WY3", "DPO", "5XX", "E3D", "EZZ"},
+			{"NBSWY3DPO5XXE3", "DEZZ"},
+		}, io.ErrUnexpectedEOF},
+
+		// Test with "ZZY" as extra input
+		{"helloworld", [][]string{
+			{"NBSW", "Y3DP", "O5XX", "E3DE", "ZZY"},
+			{"NBSWY3DPO5XXE3DE", "ZZY"},
+			{"NBSWY3DPO5XXE3DEZZY"},
+			{"NBS", "WY3", "DPO", "5XX", "E3D", "EZZY"},
+			{"NBSWY3DPO5XXE3", "DEZZY"},
+		}, io.ErrUnexpectedEOF},
+
+		// Normal case, this is valid input
+		{"helloworld", [][]string{
+			{"NBSW", "Y3DP", "O5XX", "E3DE"},
+			{"NBSWY3DPO5XXE3DE"},
+			{"NBS", "WY3", "DPO", "5XX", "E3D", "E"},
+			{"NBSWY3DPO5XXE3", "DE"},
+		}, nil},
+
+		// MZXW6YTB = fooba
+		{"fooba", [][]string{
+			{"MZXW6YTBZZ"},
+			{"MZXW6YTBZ", "Z"},
+			{"MZXW6YTB", "ZZ"},
+			{"MZXW6YT", "BZZ"},
+			{"MZXW6Y", "TBZZ"},
+			{"MZXW6Y", "TB", "ZZ"},
+			{"MZXW6", "YTBZZ"},
+			{"MZXW6", "YTB", "ZZ"},
+			{"MZXW6", "YT", "BZZ"},
+		}, io.ErrUnexpectedEOF},
+
+		// Normal case, this is valid input
+		{"fooba", [][]string{
+			{"MZXW6YTB"},
+			{"MZXW6YT", "B"},
+			{"MZXW6Y", "TB"},
+			{"MZXW6", "YTB"},
+			{"MZXW6", "YT", "B"},
+			{"MZXW", "6YTB"},
+			{"MZXW", "6Y", "TB"},
+		}, nil},
+	}
+
+	for _, testcase := range testcases {
+		for _, chunks := range testcase.chunkCombinations {
+			pr, pw := io.Pipe()
+
+			// Write the encoded chunks into the pipe
+			go func() {
+				for _, chunk := range chunks {
+					pw.Write([]byte(chunk))
+				}
+				pw.Close()
+			}()
+
+			decoder := NewDecoder(StdEncoding, pr)
+			_, err := io.ReadAll(decoder)
+
+			if err != testcase.expected {
+				t.Errorf("Expected %v, got %v; case %s %+v", testcase.expected, err, testcase.prefix, chunks)
+			}
+		}
+	}
+}
+
+func TestBufferedDecodingPadding(t *testing.T) {
+	testcases := []struct {
+		chunks        []string
+		expectedError string
+	}{
+		{[]string{
+			"I4======",
+			"==",
+		}, "unexpected EOF"},
+
+		{[]string{
+			"I4======N4======",
+		}, "illegal base32 data at input byte 2"},
+
+		{[]string{
+			"I4======",
+			"N4======",
+		}, "illegal base32 data at input byte 0"},
+
+		{[]string{
+			"I4======",
+			"========",
+		}, "illegal base32 data at input byte 0"},
+
+		{[]string{
+			"I4I4I4I4",
+			"I4======",
+			"I4======",
+		}, "illegal base32 data at input byte 0"},
+	}
+
+	for _, testcase := range testcases {
+		testcase := testcase
+		pr, pw := io.Pipe()
+		go func() {
+			for _, chunk := range testcase.chunks {
+				_, _ = pw.Write([]byte(chunk))
+			}
+			_ = pw.Close()
+		}()
+
+		decoder := NewDecoder(StdEncoding, pr)
+		_, err := io.ReadAll(decoder)
+
+		if err == nil && len(testcase.expectedError) != 0 {
+			t.Errorf("case %q: got nil error, want %v", testcase.chunks, testcase.expectedError)
+		} else if err.Error() != testcase.expectedError {
+			t.Errorf("case %q: got %v, want %v", testcase.chunks, err, testcase.expectedError)
+		}
+	}
+}
+
+func TestEncodedLen(t *testing.T) {
+	var rawStdEncoding = StdEncoding.WithPadding(NoPadding)
+	type test struct {
+		enc  *Encoding
+		n    int
+		want int64
+	}
+	tests := []test{
+		{StdEncoding, 0, 0},
+		{StdEncoding, 1, 8},
+		{StdEncoding, 2, 8},
+		{StdEncoding, 3, 8},
+		{StdEncoding, 4, 8},
+		{StdEncoding, 5, 8},
+		{StdEncoding, 6, 16},
+		{StdEncoding, 10, 16},
+		{StdEncoding, 11, 24},
+		{rawStdEncoding, 0, 0},
+		{rawStdEncoding, 1, 2},
+		{rawStdEncoding, 2, 4},
+		{rawStdEncoding, 3, 5},
+		{rawStdEncoding, 4, 7},
+		{rawStdEncoding, 5, 8},
+		{rawStdEncoding, 6, 10},
+		{rawStdEncoding, 7, 12},
+		{rawStdEncoding, 10, 16},
+		{rawStdEncoding, 11, 18},
+	}
+	// check overflow
+	switch strconv.IntSize {
+	case 32:
+		tests = append(tests, test{rawStdEncoding, (math.MaxInt-4)/8 + 1, 429496730})
+		tests = append(tests, test{rawStdEncoding, math.MaxInt/8*5 + 4, math.MaxInt})
+	case 64:
+		tests = append(tests, test{rawStdEncoding, (math.MaxInt-4)/8 + 1, 1844674407370955162})
+		tests = append(tests, test{rawStdEncoding, math.MaxInt/8*5 + 4, math.MaxInt})
+	}
+	for _, tt := range tests {
+		if got := tt.enc.EncodedLen(tt.n); int64(got) != tt.want {
+			t.Errorf("EncodedLen(%d): got %d, want %d", tt.n, got, tt.want)
+		}
+	}
+}
+
+func TestDecodedLen(t *testing.T) {
+	var rawStdEncoding = StdEncoding.WithPadding(NoPadding)
+	type test struct {
+		enc  *Encoding
+		n    int
+		want int64
+	}
+	tests := []test{
+		{StdEncoding, 0, 0},
+		{StdEncoding, 8, 5},
+		{StdEncoding, 16, 10},
+		{StdEncoding, 24, 15},
+		{rawStdEncoding, 0, 0},
+		{rawStdEncoding, 2, 1},
+		{rawStdEncoding, 4, 2},
+		{rawStdEncoding, 5, 3},
+		{rawStdEncoding, 7, 4},
+		{rawStdEncoding, 8, 5},
+		{rawStdEncoding, 10, 6},
+		{rawStdEncoding, 12, 7},
+		{rawStdEncoding, 16, 10},
+		{rawStdEncoding, 18, 11},
+	}
+	// check overflow
+	switch strconv.IntSize {
+	case 32:
+		tests = append(tests, test{rawStdEncoding, math.MaxInt/5 + 1, 268435456})
+		tests = append(tests, test{rawStdEncoding, math.MaxInt, 1342177279})
+	case 64:
+		tests = append(tests, test{rawStdEncoding, math.MaxInt/5 + 1, 1152921504606846976})
+		tests = append(tests, test{rawStdEncoding, math.MaxInt, 5764607523034234879})
+	}
+	for _, tt := range tests {
+		if got := tt.enc.DecodedLen(tt.n); int64(got) != tt.want {
+			t.Errorf("DecodedLen(%d): got %d, want %d", tt.n, got, tt.want)
+		}
+	}
+}
+
+func TestWithoutPaddingClose(t *testing.T) {
+	encodings := []*Encoding{
+		StdEncoding,
+		StdEncoding.WithPadding(NoPadding),
+	}
+
+	for _, encoding := range encodings {
+		for _, testpair := range pairs {
+
+			var buf strings.Builder
+			encoder := NewEncoder(encoding, &buf)
+			encoder.Write([]byte(testpair.decoded))
+			encoder.Close()
+
+			expected := testpair.encoded
+			if encoding.padChar == NoPadding {
+				expected = strings.ReplaceAll(expected, "=", "")
+			}
+
+			res := buf.String()
+
+			if res != expected {
+				t.Errorf("Expected %s got %s; padChar=%d", expected, res, encoding.padChar)
+			}
+		}
+	}
+}
+
+func TestDecodeReadAll(t *testing.T) {
+	encodings := []*Encoding{
+		StdEncoding,
+		StdEncoding.WithPadding(NoPadding),
+	}
+
+	for _, pair := range pairs {
+		for encIndex, encoding := range encodings {
+			encoded := pair.encoded
+			if encoding.padChar == NoPadding {
+				encoded = strings.ReplaceAll(encoded, "=", "")
+			}
+
+			decReader, err := io.ReadAll(NewDecoder(encoding, strings.NewReader(encoded)))
+			if err != nil {
+				t.Errorf("NewDecoder error: %v", err)
+			}
+
+			if pair.decoded != string(decReader) {
+				t.Errorf("Expected %s got %s; Encoding %d", pair.decoded, decReader, encIndex)
+			}
+		}
+	}
+}
+
+func TestDecodeSmallBuffer(t *testing.T) {
+	encodings := []*Encoding{
+		StdEncoding,
+		StdEncoding.WithPadding(NoPadding),
+	}
+
+	for bufferSize := 1; bufferSize < 200; bufferSize++ {
+		for _, pair := range pairs {
+			for encIndex, encoding := range encodings {
+				encoded := pair.encoded
+				if encoding.padChar == NoPadding {
+					encoded = strings.ReplaceAll(encoded, "=", "")
+				}
+
+				decoder := NewDecoder(encoding, strings.NewReader(encoded))
+
+				var allRead []byte
+
+				for {
+					buf := make([]byte, bufferSize)
+					n, err := decoder.Read(buf)
+					allRead = append(allRead, buf[0:n]...)
+					if err == io.EOF {
+						break
+					}
+					if err != nil {
+						t.Error(err)
+					}
+				}
+
+				if pair.decoded != string(allRead) {
+					t.Errorf("Expected %s got %s; Encoding %d; bufferSize %d", pair.decoded, allRead, encIndex, bufferSize)
+				}
+			}
+		}
+	}
+}
diff --git a/src/encoding/base32/example_test.go b/src/encoding/base32/example_test.go
new file mode 100644
index 0000000..251624f
--- /dev/null
+++ b/src/encoding/base32/example_test.go
@@ -0,0 +1,68 @@
+// 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.
+
+// Keep in sync with ../base64/example_test.go.
+
+package base32_test
+
+import (
+	"encoding/base32"
+	"fmt"
+	"os"
+)
+
+func ExampleEncoding_EncodeToString() {
+	data := []byte("any + old & data")
+	str := base32.StdEncoding.EncodeToString(data)
+	fmt.Println(str)
+	// Output:
+	// MFXHSIBLEBXWYZBAEYQGIYLUME======
+}
+
+func ExampleEncoding_Encode() {
+	data := []byte("Hello, world!")
+	dst := make([]byte, base32.StdEncoding.EncodedLen(len(data)))
+	base32.StdEncoding.Encode(dst, data)
+	fmt.Println(string(dst))
+	// Output:
+	// JBSWY3DPFQQHO33SNRSCC===
+}
+
+func ExampleEncoding_DecodeString() {
+	str := "ONXW2ZJAMRQXIYJAO5UXI2BAAAQGC3TEEDX3XPY="
+	data, err := base32.StdEncoding.DecodeString(str)
+	if err != nil {
+		fmt.Println("error:", err)
+		return
+	}
+	fmt.Printf("%q\n", data)
+	// Output:
+	// "some data with \x00 and \ufeff"
+}
+
+func ExampleEncoding_Decode() {
+	str := "JBSWY3DPFQQHO33SNRSCC==="
+	dst := make([]byte, base32.StdEncoding.DecodedLen(len(str)))
+	n, err := base32.StdEncoding.Decode(dst, []byte(str))
+	if err != nil {
+		fmt.Println("decode error:", err)
+		return
+	}
+	dst = dst[:n]
+	fmt.Printf("%q\n", dst)
+	// Output:
+	// "Hello, world!"
+}
+
+func ExampleNewEncoder() {
+	input := []byte("foo\x00bar")
+	encoder := base32.NewEncoder(base32.StdEncoding, os.Stdout)
+	encoder.Write(input)
+	// Must close the encoder when finished to flush any partial blocks.
+	// If you comment out the following line, the last partial block "r"
+	// won't be encoded.
+	encoder.Close()
+	// Output:
+	// MZXW6ADCMFZA====
+}