diff --git a/id.go b/id.go new file mode 100644 index 0000000..a10ea2f --- /dev/null +++ b/id.go @@ -0,0 +1,43 @@ +package idg + +import ( + "crypto/md5" + "fmt" + "io" + "time" +) + +// This thing contains a channel that when initialized (see NewIdGenerator) +// will return a bunch of (as best as I can tell) unique md5 hashes. +// +// we use this for naming players, games, etc. +// +// It will consume a single goroutine +type IdGenerator struct { + id chan int64 +} + +func NewIdGenerator() *IdGenerator { + return &IdGenerator{ + id: make(chan int64), + } +} + +// Run is called (typically in a gorotine) to allow for queries to be made +// against IdGenerator.id throgh the Hash method. +func (idg *IdGenerator) Run() { + var i int64 + for i = 0; ; i++ { + idg.id <- i + } +} + +// Hash is the method used by a properly instantiated IdGenerator that gives +// fairly unique strings. They are currently truncated md5 hashes of the time +// plus a unique counter +func (id *IdGenerator) Hash() string { + h := md5.New() + ns := time.Now().UnixNano() + <-id.id + io.WriteString(h, fmt.Sprintf("%d", ns)) + return fmt.Sprintf("%x", h.Sum(nil))[:8] +} diff --git a/id_test.go b/id_test.go new file mode 100644 index 0000000..e20a1ec --- /dev/null +++ b/id_test.go @@ -0,0 +1,19 @@ +package idg + +import ( + "testing" +) + +func TestIDGenerator(t *testing.T) { + cache := make(map[string]bool) + var cur string + gg := NewIdGenerator() + go gg.Run() + for i := 0; i < 10000; i++ { + cur = gg.Hash() + if _, ok := cache[cur]; ok { + t.Errorf("unexpected duplicate key") + } + cache[cur] = true + } +}