added vendor

vendor/github.com/client9/misspell/ascii.go

@@ -0,0 +1,62 @@
+package misspell
+
+// ByteToUpper converts an ascii byte to upper cases
+// Uses a branchless algorithm
+func ByteToUpper(x byte) byte {
+	b := byte(0x80) | x
+	c := b - byte(0x61)
+	d := ^(b - byte(0x7b))
+	e := (c & d) & (^x & 0x7f)
+	return x - (e >> 2)
+}
+
+// ByteToLower converts an ascii byte to lower case
+// uses a branchless algorithm
+func ByteToLower(eax byte) byte {
+	ebx := eax&byte(0x7f) + byte(0x25)
+	ebx = ebx&byte(0x7f) + byte(0x1a)
+	ebx = ((ebx & ^eax) >> 2) & byte(0x20)
+	return eax + ebx
+}
+
+// ByteEqualFold does ascii compare, case insensitive
+func ByteEqualFold(a, b byte) bool {
+	return a == b || ByteToLower(a) == ByteToLower(b)
+}
+
+// StringEqualFold ASCII case-insensitive comparison
+// golang toUpper/toLower for both bytes and strings
+// appears to be Unicode based which is super slow
+// based from https://codereview.appspot.com/5180044/patch/14007/21002
+func StringEqualFold(s1, s2 string) bool {
+	if len(s1) != len(s2) {
+		return false
+	}
+	for i := 0; i < len(s1); i++ {
+		c1 := s1[i]
+		c2 := s2[i]
+		// c1 & c2
+		if c1 != c2 {
+			c1 |= 'a' - 'A'
+			c2 |= 'a' - 'A'
+			if c1 != c2 || c1 < 'a' || c1 > 'z' {
+				return false
+			}
+		}
+	}
+	return true
+}
+
+// StringHasPrefixFold is similar to strings.HasPrefix but comparison
+// is done ignoring ASCII case.
+// /
+func StringHasPrefixFold(s1, s2 string) bool {
+	// prefix is bigger than input --> false
+	if len(s1) < len(s2) {
+		return false
+	}
+	if len(s1) == len(s2) {
+		return StringEqualFold(s1, s2)
+	}
+	return StringEqualFold(s1[:len(s2)], s2)
+}