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Add encoding/hex

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R=rsc
http://go/go-review/1015012
This commit is contained in:
Adam Langley 2009-10-26 16:34:36 -07:00
parent 5e6194cc1b
commit 569a1cd545
5 changed files with 273 additions and 5 deletions
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11
src/pkg/Make.deps
View File

@ -5,8 +5,8 @@ bignum.install: fmt.install
bufio.install: io.install os.install strconv.install utf8.install
bytes.install: os.install unicode.install utf8.install
compress/flate.install: bufio.install bytes.install io.install math.install os.install sort.install strconv.install
compress/gzip.install: bufio.install compress/flate.install hash.install hash/crc32.install io.install os.install
compress/zlib.install: bufio.install compress/flate.install hash.install hash/adler32.install io.install os.install
compress/gzip.install: bufio.install compress/flate.install hash/crc32.install hash.install io.install os.install
compress/zlib.install: bufio.install compress/flate.install hash/adler32.install hash.install io.install os.install
container/heap.install: sort.install
container/list.install:
container/ring.install:
@ -26,16 +26,17 @@ ebnf.install: container/vector.install go/scanner.install go/token.install os.in
encoding/ascii85.install: bytes.install io.install os.install strconv.install
encoding/base64.install: bytes.install io.install os.install strconv.install
encoding/binary.install: io.install math.install os.install reflect.install
encoding/hex.install: os.install strconv.install strings.install
encoding/git85.install: bytes.install io.install os.install strconv.install
encoding/pem.install: bytes.install encoding/base64.install strings.install
exec.install: os.install strings.install
exp/datafmt.install: bytes.install container/vector.install fmt.install go/scanner.install go/token.install io.install os.install reflect.install runtime.install strconv.install strings.install
exp/eval.install: bignum.install fmt.install go/ast.install go/parser.install go/scanner.install go/token.install log.install os.install reflect.install runtime.install strconv.install strings.install
exp/eval.install: bignum.install fmt.install go/ast.install go/parser.install go/scanner.install go/token.install log.install os.install reflect.install runtime.install sort.install strconv.install strings.install
exp/iterable.install: container/vector.install
expvar.install: bytes.install fmt.install http.install log.install strconv.install sync.install
flag.install: fmt.install os.install strconv.install
fmt.install: io.install os.install reflect.install strconv.install utf8.install
go/ast.install: go/token.install unicode.install utf8.install
go/ast.install: fmt.install go/token.install unicode.install utf8.install
go/doc.install: container/vector.install go/ast.install go/token.install io.install regexp.install sort.install strings.install template.install
go/parser.install: bytes.install container/vector.install fmt.install go/ast.install go/scanner.install go/token.install io.install os.install path.install strings.install
go/printer.install: bytes.install container/vector.install fmt.install go/ast.install go/token.install io.install os.install reflect.install runtime.install strings.install tabwriter.install
@ -47,7 +48,7 @@ hash/adler32.install: hash.install os.install
hash/crc32.install: hash.install os.install
http.install: bufio.install bytes.install container/vector.install fmt.install io.install log.install net.install os.install path.install strconv.install strings.install utf8.install
image.install:
image/png.install: bufio.install compress/zlib.install hash.install hash/crc32.install image.install io.install os.install strconv.install
image/png.install: bufio.install compress/zlib.install hash/crc32.install hash.install image.install io.install os.install strconv.install
io.install: bytes.install os.install sort.install strings.install sync.install
json.install: bytes.install container/vector.install fmt.install math.install reflect.install strconv.install strings.install utf8.install
log.install: fmt.install io.install os.install runtime.install time.install

1
src/pkg/Makefile
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@ -41,6 +41,7 @@ DIRS=\
encoding/base64\
encoding/binary\
encoding/git85\
encoding/hex\
encoding/pem\
exec\
exp/datafmt\

11
src/pkg/encoding/hex/Makefile Normal file
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@ -0,0 +1,11 @@
# 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.
include $(GOROOT)/src/Make.$(GOARCH)
TARG=encoding/hex
GOFILES=\
hex.go\
include $(GOROOT)/src/Make.pkg

108
src/pkg/encoding/hex/hex.go Normal file
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@ -0,0 +1,108 @@
// 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.
// This package implements hexadecimal encoding and decoding.
package hex
import (
"os";
"strconv";
"strings";
)
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(src, dst []byte) int {
for i, v := range src {
dst[i*2] = hextable[v>>4];
dst[i*2 + 1] = hextable[v&0x0f];
}
return len(src)*2;
}
// OddLengthInputError results from decoding an odd length slice.
type OddLengthInputError struct{}
func (OddLengthInputError) String() string {
return "odd length hex string";
}
// InvalidHexCharError results from finding an invalid character in a hex string.
type InvalidHexCharError byte
func (e InvalidHexCharError) String() string {
return "invalid hex char: " + strconv.Itoa(int(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 OddLengthInputError or an
// InvalidHexCharError.
func Decode(src, dst []byte) (int, os.Error) {
if len(src)%2 == 1 {
return 0, OddLengthInputError{};
}
for i := 0; i < len(src)/2; i++ {
a, ok := fromHexChar(src[i*2]);
if !ok {
return 0, InvalidHexCharError(src[i*2]);
}
b, ok := fromHexChar(src[i*2 + 1]);
if !ok {
return 0, InvalidHexCharError(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(src, dst);
return string(dst);
}
// DecodeString returns the bytes represented by the hexadecimal string s.
func DecodeString(s string) ([]byte, os.Error) {
src := strings.Bytes(s);
dst := make([]byte, DecodedLen(len(src)));
_, err := Decode(src, dst);
if err != nil {
return nil, err;
}
return dst, nil;
}

147
src/pkg/encoding/hex/hex_test.go Normal file
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@ -0,0 +1,147 @@
// 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 encodeTest struct {
in, out []byte;
}
var encodeTests = []encodeTest{
encodeTest{[]byte{}, []byte{}},
encodeTest{[]byte{0x01}, []byte{'0', '1'}},
encodeTest{[]byte{0xff}, []byte{'f', 'f'}},
encodeTest{[]byte{0xff, 00}, []byte{'f', 'f', '0', '0'}},
encodeTest{[]byte{0}, []byte{'0', '0'}},
encodeTest{[]byte{1}, []byte{'0', '1'}},
encodeTest{[]byte{2}, []byte{'0', '2'}},
encodeTest{[]byte{3}, []byte{'0', '3'}},
encodeTest{[]byte{4}, []byte{'0', '4'}},
encodeTest{[]byte{5}, []byte{'0', '5'}},
encodeTest{[]byte{6}, []byte{'0', '6'}},
encodeTest{[]byte{7}, []byte{'0', '7'}},
encodeTest{[]byte{8}, []byte{'0', '8'}},
encodeTest{[]byte{9}, []byte{'0', '9'}},
encodeTest{[]byte{10}, []byte{'0', 'a'}},
encodeTest{[]byte{11}, []byte{'0', 'b'}},
encodeTest{[]byte{12}, []byte{'0', 'c'}},
encodeTest{[]byte{13}, []byte{'0', 'd'}},
encodeTest{[]byte{14}, []byte{'0', 'e'}},
encodeTest{[]byte{15}, []byte{'0', 'f'}},
}
func TestEncode(t *testing.T) {
for i, test := range encodeTests {
dst := make([]byte, EncodedLen(len(test.in)));
n := Encode(test.in, dst);
if n != len(dst) {
t.Errorf("#%d: bad return value: got: %d want: %d", i, n, len(dst));
}
if bytes.Compare(dst, test.out) != 0 {
t.Errorf("#%d: got: %#v want: %#v", i, dst, test.out);
}
}
}
type decodeTest struct {
in, out []byte;
ok bool;
}
var decodeTests = []decodeTest{
decodeTest{[]byte{}, []byte{}, true},
decodeTest{[]byte{'0'}, []byte{}, false},
decodeTest{[]byte{'0', 'g'}, []byte{}, false},
decodeTest{[]byte{'0', '0'}, []byte{0}, true},
decodeTest{[]byte{'0', '1'}, []byte{1}, true},
decodeTest{[]byte{'0', '2'}, []byte{2}, true},
decodeTest{[]byte{'0', '3'}, []byte{3}, true},
decodeTest{[]byte{'0', '4'}, []byte{4}, true},
decodeTest{[]byte{'0', '5'}, []byte{5}, true},
decodeTest{[]byte{'0', '6'}, []byte{6}, true},
decodeTest{[]byte{'0', '7'}, []byte{7}, true},
decodeTest{[]byte{'0', '8'}, []byte{8}, true},
decodeTest{[]byte{'0', '9'}, []byte{9}, true},
decodeTest{[]byte{'0', 'a'}, []byte{10}, true},
decodeTest{[]byte{'0', 'b'}, []byte{11}, true},
decodeTest{[]byte{'0', 'c'}, []byte{12}, true},
decodeTest{[]byte{'0', 'd'}, []byte{13}, true},
decodeTest{[]byte{'0', 'e'}, []byte{14}, true},
decodeTest{[]byte{'0', 'f'}, []byte{15}, true},
decodeTest{[]byte{'0', 'A'}, []byte{10}, true},
decodeTest{[]byte{'0', 'B'}, []byte{11}, true},
decodeTest{[]byte{'0', 'C'}, []byte{12}, true},
decodeTest{[]byte{'0', 'D'}, []byte{13}, true},
decodeTest{[]byte{'0', 'E'}, []byte{14}, true},
decodeTest{[]byte{'0', 'F'}, []byte{15}, true},
}
func TestDecode(t *testing.T) {
for i, test := range decodeTests {
dst := make([]byte, DecodedLen(len(test.in)));
n, err := Decode(test.in, dst);
if err == nil && n != len(dst) {
t.Errorf("#%d: bad return value: got:%d want:%d", i, n, len(dst));
}
if test.ok != (err == nil) {
t.Errorf("#%d: unexpected err value: %s", i, err);
}
if err == nil && bytes.Compare(dst, test.out) != 0 {
t.Errorf("#%d: got: %#v want: %#v", i, dst, test.out);
}
}
}
type encodeStringTest struct {
in []byte;
out string;
}
var encodeStringTests = []encodeStringTest{
encodeStringTest{[]byte{}, ""},
encodeStringTest{[]byte{0}, "00"},
encodeStringTest{[]byte{0, 1}, "0001"},
encodeStringTest{[]byte{0, 1, 255}, "0001ff"},
}
func TestEncodeToString(t *testing.T) {
for i, test := range encodeStringTests {
s := EncodeToString(test.in);
if s != test.out {
t.Errorf("#%d got:%s want:%s", i, s, test.out);
}
}
}
type decodeStringTest struct {
in string;
out []byte;
ok bool;
}
var decodeStringTests = []decodeStringTest{
decodeStringTest{"", []byte{}, true},
decodeStringTest{"0", []byte{}, false},
decodeStringTest{"00", []byte{0}, true},
decodeStringTest{"0g", []byte{}, false},
decodeStringTest{"00ff00", []byte{0, 255, 0}, true},
decodeStringTest{"0000ff", []byte{0, 0, 255}, true},
}
func TestDecodeString(t *testing.T) {
for i, test := range decodeStringTests {
dst, err := DecodeString(test.in);
if test.ok != (err == nil) {
t.Errorf("#%d: unexpected err value: %s", i, err);
}
if err == nil && bytes.Compare(dst, test.out) != 0 {
t.Errorf("#%d: got: %#v want: #%v", i, dst, test.out);
}
}
}