From 569a1cd545ec2fbd0f8307b65576e038d35cc4cc Mon Sep 17 00:00:00 2001 From: Adam Langley Date: Mon, 26 Oct 2009 16:34:36 -0700 Subject: [PATCH] Add encoding/hex R=rsc http://go/go-review/1015012 --- src/pkg/Make.deps | 11 +-- src/pkg/Makefile | 1 + src/pkg/encoding/hex/Makefile | 11 +++ src/pkg/encoding/hex/hex.go | 108 +++++++++++++++++++++++ src/pkg/encoding/hex/hex_test.go | 147 +++++++++++++++++++++++++++++++ 5 files changed, 273 insertions(+), 5 deletions(-) create mode 100644 src/pkg/encoding/hex/Makefile create mode 100644 src/pkg/encoding/hex/hex.go create mode 100644 src/pkg/encoding/hex/hex_test.go diff --git a/src/pkg/Make.deps b/src/pkg/Make.deps index 4ccc210eef..b0191defcb 100644 --- a/src/pkg/Make.deps +++ b/src/pkg/Make.deps @@ -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 diff --git a/src/pkg/Makefile b/src/pkg/Makefile index 4f74bb4f42..cc0ebe69a4 100644 --- a/src/pkg/Makefile +++ b/src/pkg/Makefile @@ -41,6 +41,7 @@ DIRS=\ encoding/base64\ encoding/binary\ encoding/git85\ + encoding/hex\ encoding/pem\ exec\ exp/datafmt\ diff --git a/src/pkg/encoding/hex/Makefile b/src/pkg/encoding/hex/Makefile new file mode 100644 index 0000000000..bcfed2d45a --- /dev/null +++ b/src/pkg/encoding/hex/Makefile @@ -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 diff --git a/src/pkg/encoding/hex/hex.go b/src/pkg/encoding/hex/hex.go new file mode 100644 index 0000000000..32ec42e245 --- /dev/null +++ b/src/pkg/encoding/hex/hex.go @@ -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; +} diff --git a/src/pkg/encoding/hex/hex_test.go b/src/pkg/encoding/hex/hex_test.go new file mode 100644 index 0000000000..8d976f6836 --- /dev/null +++ b/src/pkg/encoding/hex/hex_test.go @@ -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); + } + } +} -- 2.48.1