new /x/jsonx and /x/mathx util sub-packages

x/jsonx/jsonx.go

@@ -0,0 +1,21 @@
+package jsonx
+
+import "bytes"
+
+var (
+	quoteLiteral    = '"'
+	emptyQuoteBytes = []byte(`""`)
+	nullLiteral     = []byte("null")
+)
+
+func isNull(b []byte) bool {
+	return len(b) == 0 || bytes.Equal(b, nullLiteral)
+}
+
+func trimQuotesFunc(r rune) bool {
+	return r == quoteLiteral
+}
+
+func trimQuotes(b []byte) []byte {
+	return bytes.TrimFunc(b, trimQuotesFunc)
+}