Initial QSfera import

Server/vendor/github.com/segmentio/asm/base64/base64.go

@@ -0,0 +1,67 @@
+package base64
+
+import (
+	"encoding/base64"
+)
+
+const (
+	StdPadding rune = base64.StdPadding
+	NoPadding  rune = base64.NoPadding
+
+	encodeStd  = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/"
+	encodeURL  = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789-_"
+	encodeIMAP = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+,"
+
+	letterRange = int8('Z' - 'A' + 1)
+)
+
+// StdEncoding is the standard base64 encoding, as defined in RFC 4648.
+var StdEncoding = NewEncoding(encodeStd)
+
+// URLEncoding is the alternate base64 encoding defined in RFC 4648.
+// It is typically used in URLs and file names.
+var URLEncoding = NewEncoding(encodeURL)
+
+// RawStdEncoding is the standard unpadded base64 encoding defined in RFC 4648 section 3.2.
+// This is the same as StdEncoding but omits padding characters.
+var RawStdEncoding = StdEncoding.WithPadding(NoPadding)
+
+// RawURLEncoding is the unpadded alternate base64 encoding defined in RFC 4648.
+// This is the same as URLEncoding but omits padding characters.
+var RawURLEncoding = URLEncoding.WithPadding(NoPadding)
+
+// NewEncoding returns a new padded Encoding defined by the given alphabet,
+// which must be a 64-byte string that does not contain the padding character
+// or CR / LF ('\r', '\n'). Unlike the standard library, the encoding alphabet
+// cannot be abitrary, and it must follow one of the know standard encoding
+// variants.
+//
+// Required alphabet values:
+//     * [0,26):  characters 'A'..'Z'
+//     * [26,52): characters 'a'..'z'
+//     * [52,62): characters '0'..'9'
+// Flexible alphabet value options:
+//     * RFC 4648, RFC 1421, RFC 2045, RFC 2152, RFC 4880: '+' and '/'
+//     * RFC 4648 URI: '-' and '_'
+//     * RFC 3501: '+' and ','
+//
+// The resulting Encoding uses the default padding character ('='), which may
+// be changed or disabled via WithPadding. The padding characters is urestricted,
+// but it must be a character outside of the encoder alphabet.
+func NewEncoding(encoder string) *Encoding {
+	if len(encoder) != 64 {
+		panic("encoding alphabet is not 64-bytes long")
+	}
+
+	if _, ok := allowedEncoding[encoder]; !ok {
+		panic("non-standard encoding alphabets are not supported")
+	}
+
+	return newEncoding(encoder)
+}
+
+var allowedEncoding = map[string]struct{}{
+	encodeStd:  {},
+	encodeURL:  {},
+	encodeIMAP: {},
+}