v0.0.296 add csid.generateIDFromSeed

bfcodegen/csid-generate.template

@@ -65,6 +65,27 @@ func generateID(prefix string) string {
 	return prefix + k + checkstr
 }
 
+func generateIDFromSeed(prefix string, seed string) string {
+	h := sha256.New()
+
+	iddata := ""
+	for len(iddata) < idlen-len(prefix)-checklen {
+		h.Write([]byte(seed))
+		bs := h.Sum(nil)
+		iddata += langext.NewAnyBaseConverter(idCharset).Encode(bs)
+	}
+
+	checksum := 0
+	for i := 0; i < idlen-len(prefix)-checklen; i++ {
+		ichr := int(iddata[i])
+		checksum = (checksum + charSetReverseMap[ichr]) % (idCharsetLen)
+	}
+
+	checkstr := string(idCharset[checksum%idCharsetLen])
+
+	return prefix + iddata[:(idlen-len(prefix)-checklen)] + checkstr
+}
+
 func validateID(prefix string, value string) error {
 	if len(value) != idlen {
 		return exerr.New(exerr.TypeInvalidCSID, "id has the wrong length").Str("value", value).Build()