helpers.go -> utils.go and lowercase util functions.

utils.go

@@ -0,0 +1,77 @@
+package nostr
+
+import (
+	"strings"
+
+	"golang.org/x/exp/constraints"
+)
+
+func similar[E constraints.Ordered](as, bs []E) bool {
+	if len(as) != len(bs) {
+		return false
+	}
+
+	for _, a := range as {
+		for _, b := range bs {
+			if b == a {
+				goto next
+			}
+		}
+		// didn't find a B that corresponded to the current A
+		return false
+
+	next:
+		continue
+	}
+
+	return true
+}
+
+func containsPrefixOf(haystack []string, needle string) bool {
+	for _, hay := range haystack {
+		if strings.HasPrefix(needle, hay) {
+			return true
+		}
+	}
+	return false
+}
+
+// Escaping strings for JSON encoding according to RFC8259.
+// Also encloses result in quotation marks "".
+func escapeString(dst []byte, s string) []byte {
+	dst = append(dst, '"')
+	for i := 0; i < len(s); i++ {
+		c := s[i]
+		switch {
+		case c == '"':
+			// quotation mark
+			dst = append(dst, []byte{'\\', '"'}...)
+		case c == '\\':
+			// reverse solidus
+			dst = append(dst, []byte{'\\', '\\'}...)
+		case c >= 0x20:
+			// default, rest below are control chars
+			dst = append(dst, c)
+		case c == 0x08:
+			dst = append(dst, []byte{'\\', 'b'}...)
+		case c < 0x09:
+			dst = append(dst, []byte{'\\', 'u', '0', '0', '0', '0' + c}...)
+		case c == 0x09:
+			dst = append(dst, []byte{'\\', 't'}...)
+		case c == 0x0a:
+			dst = append(dst, []byte{'\\', 'n'}...)
+		case c == 0x0c:
+			dst = append(dst, []byte{'\\', 'f'}...)
+		case c == 0x0d:
+			dst = append(dst, []byte{'\\', 'r'}...)
+		case c < 0x10:
+			dst = append(dst, []byte{'\\', 'u', '0', '0', '0', 0x57 + c}...)
+		case c < 0x1a:
+			dst = append(dst, []byte{'\\', 'u', '0', '0', '1', 0x20 + c}...)
+		case c < 0x20:
+			dst = append(dst, []byte{'\\', 'u', '0', '0', '1', 0x47 + c}...)
+		}
+	}
+	dst = append(dst, '"')
+	return dst
+}