Initial commit.

1 files changed, 76 insertions, 0 deletions

diff --git a/imagestore/hash.go b/imagestore/hash.go
new file mode 100644
index 0000000..d24e6fc
--- /dev/null
+++ b/imagestore/hash.go
@@ -0,0 +1,76 @@
+package imagestore
+
+import (
+	"crypto/rand"
+	"log"
+)
+
+type HashGenerator struct {
+	hashGetter chan string
+	length     int
+	store      ImageStore
+}
+
+func (this *HashGenerator) init() {
+	go func() {
+		storeObj := &StoreObject{
+			"",
+			"",
+			"original",
+			"",
+		}
+
+		for {
+			str := ""
+
+			for len(str) < this.length {
+				c := 10
+				bArr := make([]byte, c)
+				_, err := rand.Read(bArr)
+				if err != nil {
+					log.Println("error:", err)
+					break
+				}
+
+				for _, b := range bArr {
+					if len(str) == this.length {
+						break
+					}
+
+					/**
+					 * Each byte will be in [0, 256), but we only care about:
+					 *
+					 * [48, 57]     0-9
+					 * [65, 90]     A-Z
+					 * [97, 122]    a-z
+					 *
+					 * Which means that the highest bit will always be zero, since the last byte with high bit
+					 * zero is 01111111 = 127 which is higher than 122. Lower our odds of having to re-roll a byte by
+					 * dividing by two (right bit shift of 1).
+					 */
+
+					b = b >> 1
+
+					// The byte is any of        0-9                  A-Z                      a-z
+					byteIsAllowable := (b >= 48 && b <= 57) || (b >= 65 && b <= 90) || (b >= 97 && b <= 122)
+
+					if byteIsAllowable {
+						str += string(b)
+					}
+				}
+
+			}
+
+			storeObj.Name = str
+
+			exists, _ := this.store.Exists(storeObj)
+			if !exists {
+				this.hashGetter <- str
+			}
+		}
+	}()
+}
+
+func (this *HashGenerator) Get() string {
+	return <-this.hashGetter
+}