Initial version of v4 UUID

6 files changed, 509 insertions, 0 deletions

diff --git a/.gitignore b/.gitignore
new file mode 100644
index 0000000..1b60c9b
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1,4 @@
+/src/version.go
+/src/*.a
+/tests/*.a
+/tests/*.bin
diff --git a/Makefile b/Makefile
new file mode 100644
index 0000000..9caae43
--- /dev/null
+++ b/Makefile
@@ -0,0 +1,137 @@
+.POSIX:
+DATE         = 1970-01-01
+VERSION      = 0.1.0
+NAME         = guuid
+NAME_UC      = $(NAME)
+LANGUAGES    = en
+## Installation prefix.  Defaults to "/usr".
+PREFIX       = /usr
+BINDIR       = $(PREFIX)/bin
+LIBDIR       = $(PREFIX)/lib
+GOLIBDIR     = $(LIBDIR)/go
+INCLUDEDIR   = $(PREFIX)/include
+SRCDIR       = $(PREFIX)/src/$(NAME)
+SHAREDIR     = $(PREFIX)/share
+LOCALEDIR    = $(SHAREDIR)/locale
+MANDIR       = $(SHAREDIR)/man
+EXEC         = ./
+## Where to store the installation.  Empty by default.
+DESTDIR      =
+LDLIBS       =
+GOCFLAGS     = -I $(GOLIBDIR)
+GOLDFLAGS    = -L $(GOLIBDIR)
+
+
+
+.SUFFIXES:
+.SUFFIXES: .go .a .bin .bin-check
+
+
+
+objects = \
+	src/$(NAME).a                  \
+	tests/$(NAME).a                \
+	tests/main.a                   \
+	tests/libbuild.a               \
+
+sources = \
+	src/$(NAME).go                 \
+	src/version.go                 \
+
+
+derived-assets = \
+	src/version.go                 \
+	$(objects)                     \
+	tests/main.bin                 \
+	tests/libbuild.bin             \
+
+side-assets = \
+
+
+
+## Default target.  Builds all artifacts required for testing
+## and installation.
+all: $(derived-assets)
+
+
+$(objects): Makefile
+
+src/$(NAME).a: src/$(NAME).go src/version.go
+	go tool compile $(GOCFLAGS) -o $@ -p $(*F) -I $(@D) $*.go src/version.go
+
+tests/main.a: tests/main.go tests/$(NAME).a
+tests/main.a:
+	go tool compile $(GOCFLAGS) -o $@ -p $(*F) -I $(@D) $*.go
+
+tests/libbuild.a: tests/libbuild.go src/$(NAME).a
+	go tool compile $(GOCFLAGS) -o $@ -p main -I src $*.go
+
+tests/$(NAME).a: tests/$(NAME).go src/$(NAME).go src/version.go
+	go tool compile $(GOCFLAGS) -o $@ -p $(*F) $*.go src/$(*F).go src/version.go
+
+tests/libbuild.bin: tests/libbuild.a
+	go tool link   $(GOLDFLAGS) -o $@ -L src $*.a
+
+tests/main.bin: tests/main.a
+	go tool link   $(GOLDFLAGS) -o $@ -L $(@D) --extldflags '$(LDLIBS)' $*.a
+
+src/version.go: Makefile
+	echo 'package $(NAME); var version = "$(VERSION)"' > $@
+
+
+
+tests.bin-check = \
+	tests/main.bin-check           \
+	tests/libbuild.bin-check       \
+
+tests/main.bin-check: tests/main.bin
+tests/libbuild.bin-check: tests/libbuild.bin
+$(tests.bin-check):
+	$(EXEC)$*.bin
+
+check-unit: $(tests.bin-check)
+
+
+integration-tests = \
+
+.PRECIOUS: $(integration-tests)
+$(integration-tests): $(NAME).bin
+$(integration-tests): ALWAYS
+	sh $@
+
+check-integration: $(integration-tests)
+
+
+## Run all tests.  Each test suite is isolated, so that a parallel
+## build can run tests at the same time.  The required artifacts
+## are created if missing.
+check: check-unit check-integration
+
+
+
+## Remove *all* derived artifacts produced during the build.
+## A dedicated test asserts that this is always true.
+clean:
+	rm -rf $(derived-assets) $(side-assets)
+
+
+## Installs into $(DESTDIR)$(PREFIX).  Its dependency target
+## ensures that all installable artifacts are crafted beforehand.
+install: all
+	mkdir -p \
+		'$(DESTDIR)$(GOLIBDIR)'   \
+		'$(DESTDIR)$(SRCDIR)'     \
+
+	cp src/$(NAME).a     '$(DESTDIR)$(GOLIBDIR)'
+	cp $(sources)        '$(DESTDIR)$(SRCDIR)'
+
+## Uninstalls from $(DESTDIR)$(PREFIX).  This is a perfect mirror
+## of the "install" target, and removes *all* that was installed.
+## A dedicated test asserts that this is always true.
+uninstall:
+	rm -rf \
+		'$(DESTDIR)$(GOLIBDIR)'/$(NAME).a     \
+		'$(DESTDIR)$(SRCDIR)'                 \
+
+
+ALWAYS:
diff --git a/src/guuid.go b/src/guuid.go
new file mode 100644
index 0000000..9e3e2ba
--- /dev/null
+++ b/src/guuid.go
@@ -0,0 +1,103 @@
+package guuid
+
+import (
+	"crypto/rand"
+	"encoding/hex"
+	"errors"
+	"io"
+	"strings"
+)
+
+
+
+const (
+	uuidByteCount     = 16
+	uuidDashCount     = 4
+	uuidEncodedLength = (uuidByteCount * 2) + uuidDashCount
+)
+
+
+var (
+	dashIndexes = []int { 8, 13, 18, 23 }
+	emptyUUID   = UUID {}
+)
+
+var (
+	BadLengthError       = errors.New("guuid: str isn't of the correct length")
+	BadDashCountError    = errors.New("guuid: Bad count of dashes in string")
+	BadDashPositionError = errors.New("guuid: Bad char in string")
+)
+
+
+
+type UUID [uuidByteCount]byte
+
+
+
+func NewFrom(r io.Reader) (UUID, error) {
+	var uuid UUID
+	_, err := io.ReadFull(r, uuid[:])
+	if err != nil {
+		return emptyUUID, err
+	}
+	uuid[6] = (uuid[6] & 0x0f) | 0x40 // v4
+	uuid[8] = (uuid[8] & 0x3f) | 0x80 // variant 10
+	return uuid, nil
+}
+
+func New() UUID {
+	uuid, err := NewFrom(rand.Reader)
+	if err != nil {
+		panic(err)
+	}
+	return uuid
+}
+
+func (uuid UUID) String() string {
+	dst := [uuidEncodedLength]byte {
+		0, 0, 0, 0,
+		0, 0, 0, 0,
+		'-',
+		0, 0, 0, 0,
+		'-',
+		0, 0, 0, 0,
+		'-',
+		0, 0, 0, 0,
+		'-',
+		0, 0, 0, 0,
+		0, 0, 0, 0,
+		0, 0, 0, 0,
+	}
+
+	hex.Encode(dst[ 0:8],  uuid[0:4])
+	hex.Encode(dst[ 9:13], uuid[4:6])
+	hex.Encode(dst[14:18], uuid[6:8])
+	hex.Encode(dst[19:23], uuid[8:10])
+	hex.Encode(dst[24:36], uuid[10:])
+
+	return string(dst[:])
+}
+
+func FromString(str string) (UUID, error) {
+	if len(str) != uuidEncodedLength {
+		return emptyUUID, BadLengthError
+	}
+
+	if strings.Count(str, "-") != uuidDashCount {
+		return emptyUUID, BadDashCountError
+	}
+
+	for _, idx := range dashIndexes {
+		if str[idx] != '-' {
+			return emptyUUID, BadDashPositionError
+		}
+	}
+
+	hexstr := strings.Join(strings.Split(str, "-"), "")
+	data, err := hex.DecodeString(hexstr)
+	if err != nil {
+		return emptyUUID, err
+	}
+
+	return [uuidByteCount]byte(data), nil
+}
diff --git a/tests/guuid.go b/tests/guuid.go
new file mode 100644
index 0000000..6470fca
--- /dev/null
+++ b/tests/guuid.go
@@ -0,0 +1,247 @@
+package guuid
+
+import (
+	"bytes"
+	"encoding/hex"
+	"fmt"
+	"os"
+	"reflect"
+	"strings"
+)
+
+
+
+func showColour() bool {
+	return os.Getenv("NO_COLOUR") == ""
+}
+
+func testStart(name string) {
+	fmt.Fprintf(os.Stderr, "%s:\n", name)
+}
+
+func testing(message string, body func()) {
+	if showColour() {
+		fmt.Fprintf(
+			os.Stderr,
+			"\033[0;33mtesting\033[0m: %s... ",
+			message,
+		)
+		body()
+		fmt.Fprintf(os.Stderr, "\033[0;32mOK\033[0m.\n")
+	} else {
+		fmt.Fprintf(os.Stderr, "testing: %s... ", message)
+		body()
+		fmt.Fprintf(os.Stderr, "OK.\n")
+	}
+}
+
+func assertEq(given any, expected any) {
+	if !reflect.DeepEqual(given, expected) {
+		if showColour() {
+			fmt.Fprintf(os.Stderr, "\033[0;31mERR\033[0m.\n")
+		} else {
+			fmt.Fprintf(os.Stderr, "ERR.\n")
+		}
+		fmt.Fprintf(os.Stderr, "given != expected\n")
+		fmt.Fprintf(os.Stderr, "given:    %#v\n", given)
+		fmt.Fprintf(os.Stderr, "expected: %#v\n", expected)
+		os.Exit(1)
+	}
+}
+
+
+func test_NewFrom() {
+	testStart("NewFrom()")
+
+	testing("we get the same UUID from the same input", func() {
+		const s = "abcdefghijklmnop"
+
+		r1 := strings.NewReader(s)
+		uuid1, err := NewFrom(r1)
+		assertEq(err, nil)
+
+		r2 := strings.NewReader(s)
+		uuid2, err := NewFrom(r2)
+		assertEq(err, nil)
+
+		assertEq(uuid1, uuid2)
+	})
+
+	testing("we the bytes in UUID are what the reader gives us", func() {
+		input := []byte{
+			0x00,
+			0x01,
+			0x02,
+			0x03,
+			0x04,
+			0x05,
+			0x06,
+			0x07,
+			0x08,
+			0x09,
+			0x0a,
+			0x0b,
+			0x0c,
+			0x0d,
+			0x0e,
+			0x0f,
+		}
+
+		expected := UUID{
+			0x00,
+			0x01,
+			0x02,
+			0x03,
+			0x04,
+			0x05,
+			0x06 + 0x40,
+			0x07,
+			0x08 + 0x80,
+			0x09,
+			0x0a,
+			0x0b,
+			0x0c,
+			0x0d,
+			0x0e,
+			0x0f,
+		}
+
+		r := bytes.NewReader(input)
+		given, err := NewFrom(r)
+		assertEq(err, nil)
+		assertEq(given, expected)
+	})
+
+	testing("v4 and variant markers", func() {
+		input := []byte{
+			0x11,
+			0x11,
+			0x11,
+			0x11,
+			0x11,
+			0x11,
+			0x11,
+			0x11,
+			0x71,
+			0x11,
+			0x11,
+			0x11,
+			0x11,
+			0x11,
+			0x11,
+			0x11,
+		}
+
+		expected := UUID{
+			0x11,
+			0x11,
+			0x11,
+			0x11,
+			0x11,
+			0x11,
+			0x41, // not 0x11
+			0x11,
+			0xb1, // not 0x11
+			0x11,
+			0x11,
+			0x11,
+			0x11,
+			0x11,
+			0x11,
+			0x11,
+		}
+
+		r := bytes.NewReader(input)
+		given, err := NewFrom(r)
+		assertEq(err, nil)
+		assertEq(given, expected)
+	})
+}
+
+func test_New() {
+	testStart("New()")
+
+	testing("we can generate UUID values: ", func() {
+		var uuid UUID = New()
+		assertEq(len(uuid), 16)
+	})
+}
+
+func test_String() {
+	testStart("UUID.String()")
+
+	testing("simple example values", func() {
+		uuids := []UUID {
+			UUID {
+				0, 0, 0, 0, 0, 0, 0, 0,
+				0, 0, 0, 0, 0, 0, 0, 0,
+			},
+			UUID {
+				0, 1,  2,  3,  4,  5,  6,  7,
+				8, 9, 10, 11, 12, 13, 14, 15,
+			},
+			UUID {
+				222, 222, 222, 222, 222, 222, 222, 222,
+				222, 222, 222, 222, 222, 222, 222, 222,
+			},
+			UUID {
+				255, 255, 255, 255, 255, 255, 255, 255,
+				255, 255, 255, 255, 255, 255, 255, 255,
+			},
+		}
+
+		strs := []string {
+			"00000000-0000-0000-0000-000000000000",
+			"00010203-0405-0607-0809-0a0b0c0d0e0f",
+			"dededede-dede-dede-dede-dededededede",
+			"ffffffff-ffff-ffff-ffff-ffffffffffff",
+		}
+
+		for i := range uuids {
+			s1 := uuids[i].String()
+			s2 := fmt.Sprintf("%v", uuids[i])
+			assertEq(s1, strs[i])
+			assertEq(s2, strs[i])
+		}
+	})
+}
+
+func test_FromString() {
+	testStart("FromString()")
+
+	testing("UUID -> string -> UUID round trip", func() {
+		for i := 0; i < 100; i++ {
+			uuid0 := New()
+			uuid1, err := FromString(uuid0.String())
+			assertEq(err, nil)
+			assertEq(uuid0, uuid1)
+		}
+	})
+
+	testing("errors we detect", func() {
+		var err error
+
+		_, err = FromString("")
+		assertEq(err, BadLengthError)
+
+		_, err = FromString("---000000000000000000000000000000000")
+		assertEq(err, BadDashCountError)
+
+		_, err = FromString("----00000000000000000000000000000000")
+		assertEq(err, BadDashPositionError)
+
+		_, err = FromString("00000000-0000-0000-0000-00000000000g")
+		assertEq(err, hex.InvalidByteError('g'))
+
+		_, err = FromString("00000000-0000-0000-0000-000000000000")
+		assertEq(err, nil)
+	})
+}
+
+
+func MainTest() {
+	test_NewFrom()
+	test_New()
+	test_String()
+	test_FromString()
+}
diff --git a/tests/libbuild.go b/tests/libbuild.go
new file mode 100644
index 0000000..2c02686
--- /dev/null
+++ b/tests/libbuild.go
@@ -0,0 +1,11 @@
+package main
+
+import (
+	"fmt"
+
+	"guuid"
+)
+
+func main() {
+	fmt.Println(guuid.New())
+}
diff --git a/tests/main.go b/tests/main.go
new file mode 100644
index 0000000..b803727
--- /dev/null
+++ b/tests/main.go
@@ -0,0 +1,7 @@
+package main
+
+import "guuid"
+
+func main() {
+	guuid.MainTest()
+}