remove SB64 from Coze and move it to package Cyphrme/Tree

base64.go

@@ -53,27 +53,3 @@ func MustDecode(b64 string) B64 {
 	}
 	return b
 }
-
-// SB64 is useful for B64 map keys. Idiomatically, map key type should be `B64`,
-// but currently in Go map keys are only type `string`, not `[]byte`.  Since
-// B64's underlying type is `[]byte` it cannot be used as a map key. See
-// https://github.com/golang/go/issues/283 and
-// https://github.com/google/go-cmp/issues/67.  SB64 will be deprecated if/when
-// Go supports []byte keys.
-//
-// This is an acceptable hack because (from https://go.dev/blog/strings)
-//
-//	>[A] string holds arbitrary bytes. It is not required to hold Unicode text,
-//	> UTF-8 text, or any other predefined format. As far as the content of a
-//	> string is concerned, it is exactly equivalent to a slice of bytes.
-type SB64 string
-
-// String implements fmt.Stringer
-func (b SB64) String() string {
-	return B64(b).String()
-}
-
-// GoString implements fmt.GoString
-func (b SB64) GoString() string {
-	return b.String()
-}

base64_test.go

@@ -131,27 +131,6 @@ func ExampleB64_non_strict_decode() {
 	// invalid character '\r' in string literal
 }
 
-// ExampleSB64 demonstrates using SB64 as a map key and that fmt prints "RFC
-// 4648 base 64 URI canonical with padding truncated" properly.
-func ExampleSB64() {
-	b := MustDecode("zVzgRU3WFpnrlVJAnI4ZU1Od4Agl5Zd4jIP79oubOW0")
-	b2 := MustDecode("vZIAk8rjcSIKZKokGylCtVoI3DXvFYJn4XNWzf_C_FA")
-
-	lp := make(map[SB64]B64)
-	lp[SB64(b)] = B64(b2)
-
-	fmt.Printf("%s\n", SB64(b))
-	fmt.Printf("%s\n", lp)
-	fmt.Printf("%+v\n", lp)
-	fmt.Printf("%#v\n", lp)
-
-	// Output:
-	// zVzgRU3WFpnrlVJAnI4ZU1Od4Agl5Zd4jIP79oubOW0
-	// map[zVzgRU3WFpnrlVJAnI4ZU1Od4Agl5Zd4jIP79oubOW0:vZIAk8rjcSIKZKokGylCtVoI3DXvFYJn4XNWzf_C_FA]
-	// map[zVzgRU3WFpnrlVJAnI4ZU1Od4Agl5Zd4jIP79oubOW0:vZIAk8rjcSIKZKokGylCtVoI3DXvFYJn4XNWzf_C_FA]
-	// map[coze.SB64]coze.B64{zVzgRU3WFpnrlVJAnI4ZU1Od4Agl5Zd4jIP79oubOW0:vZIAk8rjcSIKZKokGylCtVoI3DXvFYJn4XNWzf_C_FA}
-}
-
 // FuzzCastB64ToString ensures that casting to and from B64 and string does not
 // cause unexpected issues (issues like replacing bytes with the unicode
 // replacement character).