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-rw-r--r--src/encoding/hex/hex.go216
-rw-r--r--src/encoding/hex/hex_test.go153
2 files changed, 369 insertions, 0 deletions
diff --git a/src/encoding/hex/hex.go b/src/encoding/hex/hex.go
new file mode 100644
index 000000000..d1fc7024a
--- /dev/null
+++ b/src/encoding/hex/hex.go
@@ -0,0 +1,216 @@
+// 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 hex implements hexadecimal encoding and decoding.
+package hex
+
+import (
+ "bytes"
+ "errors"
+ "fmt"
+ "io"
+)
+
+const hextable = "0123456789abcdef"
+
+// EncodedLen returns the length of an encoding of n source bytes.
+func EncodedLen(n int) int { return n * 2 }
+
+// Encode encodes src into EncodedLen(len(src))
+// bytes of dst. As a convenience, it returns the number
+// of bytes written to dst, but this value is always EncodedLen(len(src)).
+// Encode implements hexadecimal encoding.
+func Encode(dst, src []byte) int {
+ for i, v := range src {
+ dst[i*2] = hextable[v>>4]
+ dst[i*2+1] = hextable[v&0x0f]
+ }
+
+ return len(src) * 2
+}
+
+// ErrLength results from decoding an odd length slice.
+var ErrLength = errors.New("encoding/hex: odd length hex string")
+
+// InvalidByteError values describe errors resulting from an invalid byte in a hex string.
+type InvalidByteError byte
+
+func (e InvalidByteError) Error() string {
+ return fmt.Sprintf("encoding/hex: invalid byte: %#U", rune(e))
+}
+
+func DecodedLen(x int) int { return x / 2 }
+
+// Decode decodes src into DecodedLen(len(src)) bytes, returning the actual
+// number of bytes written to dst.
+//
+// If Decode encounters invalid input, it returns an error describing the failure.
+func Decode(dst, src []byte) (int, error) {
+ if len(src)%2 == 1 {
+ return 0, ErrLength
+ }
+
+ for i := 0; i < len(src)/2; i++ {
+ a, ok := fromHexChar(src[i*2])
+ if !ok {
+ return 0, InvalidByteError(src[i*2])
+ }
+ b, ok := fromHexChar(src[i*2+1])
+ if !ok {
+ return 0, InvalidByteError(src[i*2+1])
+ }
+ dst[i] = (a << 4) | b
+ }
+
+ return len(src) / 2, nil
+}
+
+// fromHexChar converts a hex character into its value and a success flag.
+func fromHexChar(c byte) (byte, bool) {
+ switch {
+ case '0' <= c && c <= '9':
+ return c - '0', true
+ case 'a' <= c && c <= 'f':
+ return c - 'a' + 10, true
+ case 'A' <= c && c <= 'F':
+ return c - 'A' + 10, true
+ }
+
+ return 0, false
+}
+
+// EncodeToString returns the hexadecimal encoding of src.
+func EncodeToString(src []byte) string {
+ dst := make([]byte, EncodedLen(len(src)))
+ Encode(dst, src)
+ return string(dst)
+}
+
+// DecodeString returns the bytes represented by the hexadecimal string s.
+func DecodeString(s string) ([]byte, error) {
+ src := []byte(s)
+ dst := make([]byte, DecodedLen(len(src)))
+ _, err := Decode(dst, src)
+ if err != nil {
+ return nil, err
+ }
+ return dst, nil
+}
+
+// Dump returns a string that contains a hex dump of the given data. The format
+// of the hex dump matches the output of `hexdump -C` on the command line.
+func Dump(data []byte) string {
+ var buf bytes.Buffer
+ dumper := Dumper(&buf)
+ dumper.Write(data)
+ dumper.Close()
+ return string(buf.Bytes())
+}
+
+// Dumper returns a WriteCloser that writes a hex dump of all written data to
+// w. The format of the dump matches the output of `hexdump -C` on the command
+// line.
+func Dumper(w io.Writer) io.WriteCloser {
+ return &dumper{w: w}
+}
+
+type dumper struct {
+ w io.Writer
+ rightChars [18]byte
+ buf [14]byte
+ used int // number of bytes in the current line
+ n uint // number of bytes, total
+}
+
+func toChar(b byte) byte {
+ if b < 32 || b > 126 {
+ return '.'
+ }
+ return b
+}
+
+func (h *dumper) Write(data []byte) (n int, err error) {
+ // Output lines look like:
+ // 00000010 2e 2f 30 31 32 33 34 35 36 37 38 39 3a 3b 3c 3d |./0123456789:;<=|
+ // ^ offset ^ extra space ^ ASCII of line.
+ for i := range data {
+ if h.used == 0 {
+ // At the beginning of a line we print the current
+ // offset in hex.
+ h.buf[0] = byte(h.n >> 24)
+ h.buf[1] = byte(h.n >> 16)
+ h.buf[2] = byte(h.n >> 8)
+ h.buf[3] = byte(h.n)
+ Encode(h.buf[4:], h.buf[:4])
+ h.buf[12] = ' '
+ h.buf[13] = ' '
+ _, err = h.w.Write(h.buf[4:])
+ if err != nil {
+ return
+ }
+ }
+ Encode(h.buf[:], data[i:i+1])
+ h.buf[2] = ' '
+ l := 3
+ if h.used == 7 {
+ // There's an additional space after the 8th byte.
+ h.buf[3] = ' '
+ l = 4
+ } else if h.used == 15 {
+ // At the end of the line there's an extra space and
+ // the bar for the right column.
+ h.buf[3] = ' '
+ h.buf[4] = '|'
+ l = 5
+ }
+ _, err = h.w.Write(h.buf[:l])
+ if err != nil {
+ return
+ }
+ n++
+ h.rightChars[h.used] = toChar(data[i])
+ h.used++
+ h.n++
+ if h.used == 16 {
+ h.rightChars[16] = '|'
+ h.rightChars[17] = '\n'
+ _, err = h.w.Write(h.rightChars[:])
+ if err != nil {
+ return
+ }
+ h.used = 0
+ }
+ }
+ return
+}
+
+func (h *dumper) Close() (err error) {
+ // See the comments in Write() for the details of this format.
+ if h.used == 0 {
+ return
+ }
+ h.buf[0] = ' '
+ h.buf[1] = ' '
+ h.buf[2] = ' '
+ h.buf[3] = ' '
+ h.buf[4] = '|'
+ nBytes := h.used
+ for h.used < 16 {
+ l := 3
+ if h.used == 7 {
+ l = 4
+ } else if h.used == 15 {
+ l = 5
+ }
+ _, err = h.w.Write(h.buf[:l])
+ if err != nil {
+ return
+ }
+ h.used++
+ }
+ h.rightChars[nBytes] = '|'
+ h.rightChars[nBytes+1] = '\n'
+ _, err = h.w.Write(h.rightChars[:nBytes+2])
+ return
+}
diff --git a/src/encoding/hex/hex_test.go b/src/encoding/hex/hex_test.go
new file mode 100644
index 000000000..b969636cd
--- /dev/null
+++ b/src/encoding/hex/hex_test.go
@@ -0,0 +1,153 @@
+// 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 hex
+
+import (
+ "bytes"
+ "testing"
+)
+
+type encDecTest struct {
+ enc string
+ dec []byte
+}
+
+var encDecTests = []encDecTest{
+ {"", []byte{}},
+ {"0001020304050607", []byte{0, 1, 2, 3, 4, 5, 6, 7}},
+ {"08090a0b0c0d0e0f", []byte{8, 9, 10, 11, 12, 13, 14, 15}},
+ {"f0f1f2f3f4f5f6f7", []byte{0xf0, 0xf1, 0xf2, 0xf3, 0xf4, 0xf5, 0xf6, 0xf7}},
+ {"f8f9fafbfcfdfeff", []byte{0xf8, 0xf9, 0xfa, 0xfb, 0xfc, 0xfd, 0xfe, 0xff}},
+ {"67", []byte{'g'}},
+ {"e3a1", []byte{0xe3, 0xa1}},
+}
+
+func TestEncode(t *testing.T) {
+ for i, test := range encDecTests {
+ dst := make([]byte, EncodedLen(len(test.dec)))
+ n := Encode(dst, test.dec)
+ if n != len(dst) {
+ t.Errorf("#%d: bad return value: got: %d want: %d", i, n, len(dst))
+ }
+ if string(dst) != test.enc {
+ t.Errorf("#%d: got: %#v want: %#v", i, dst, test.enc)
+ }
+ }
+}
+
+func TestDecode(t *testing.T) {
+ // Case for decoding uppercase hex characters, since
+ // Encode always uses lowercase.
+ decTests := append(encDecTests, encDecTest{"F8F9FAFBFCFDFEFF", []byte{0xf8, 0xf9, 0xfa, 0xfb, 0xfc, 0xfd, 0xfe, 0xff}})
+ for i, test := range decTests {
+ dst := make([]byte, DecodedLen(len(test.enc)))
+ n, err := Decode(dst, []byte(test.enc))
+ if err != nil {
+ t.Errorf("#%d: bad return value: got:%d want:%d", i, n, len(dst))
+ } else if !bytes.Equal(dst, test.dec) {
+ t.Errorf("#%d: got: %#v want: %#v", i, dst, test.dec)
+ }
+ }
+}
+
+func TestEncodeToString(t *testing.T) {
+ for i, test := range encDecTests {
+ s := EncodeToString(test.dec)
+ if s != test.enc {
+ t.Errorf("#%d got:%s want:%s", i, s, test.enc)
+ }
+ }
+}
+
+func TestDecodeString(t *testing.T) {
+ for i, test := range encDecTests {
+ dst, err := DecodeString(test.enc)
+ if err != nil {
+ t.Errorf("#%d: unexpected err value: %s", i, err)
+ continue
+ }
+ if !bytes.Equal(dst, test.dec) {
+ t.Errorf("#%d: got: %#v want: #%v", i, dst, test.dec)
+ }
+ }
+}
+
+type errTest struct {
+ in string
+ err string
+}
+
+var errTests = []errTest{
+ {"0", "encoding/hex: odd length hex string"},
+ {"0g", "encoding/hex: invalid byte: U+0067 'g'"},
+ {"00gg", "encoding/hex: invalid byte: U+0067 'g'"},
+ {"0\x01", "encoding/hex: invalid byte: U+0001"},
+}
+
+func TestInvalidErr(t *testing.T) {
+ for i, test := range errTests {
+ dst := make([]byte, DecodedLen(len(test.in)))
+ _, err := Decode(dst, []byte(test.in))
+ if err == nil {
+ t.Errorf("#%d: expected error; got none", i)
+ } else if err.Error() != test.err {
+ t.Errorf("#%d: got: %v want: %v", i, err, test.err)
+ }
+ }
+}
+
+func TestInvalidStringErr(t *testing.T) {
+ for i, test := range errTests {
+ _, err := DecodeString(test.in)
+ if err == nil {
+ t.Errorf("#%d: expected error; got none", i)
+ } else if err.Error() != test.err {
+ t.Errorf("#%d: got: %v want: %v", i, err, test.err)
+ }
+ }
+}
+
+func TestDumper(t *testing.T) {
+ var in [40]byte
+ for i := range in {
+ in[i] = byte(i + 30)
+ }
+
+ for stride := 1; stride < len(in); stride++ {
+ var out bytes.Buffer
+ dumper := Dumper(&out)
+ done := 0
+ for done < len(in) {
+ todo := done + stride
+ if todo > len(in) {
+ todo = len(in)
+ }
+ dumper.Write(in[done:todo])
+ done = todo
+ }
+
+ dumper.Close()
+ if !bytes.Equal(out.Bytes(), expectedHexDump) {
+ t.Errorf("stride: %d failed. got:\n%s\nwant:\n%s", stride, out.Bytes(), expectedHexDump)
+ }
+ }
+}
+
+func TestDump(t *testing.T) {
+ var in [40]byte
+ for i := range in {
+ in[i] = byte(i + 30)
+ }
+
+ out := []byte(Dump(in[:]))
+ if !bytes.Equal(out, expectedHexDump) {
+ t.Errorf("got:\n%s\nwant:\n%s", out, expectedHexDump)
+ }
+}
+
+var expectedHexDump = []byte(`00000000 1e 1f 20 21 22 23 24 25 26 27 28 29 2a 2b 2c 2d |.. !"#$%&'()*+,-|
+00000010 2e 2f 30 31 32 33 34 35 36 37 38 39 3a 3b 3c 3d |./0123456789:;<=|
+00000020 3e 3f 40 41 42 43 44 45 |>?@ABCDE|
+`)
generated by cgit v1.2.3 (git 2.39.1) at 2024-06-03 02:47:47 +0000