rtl8720dn: add support for rtl8720dn

rtl8720dn/util.go

@@ -0,0 +1,51 @@
+package rtl8720dn
+
+import (
+	"bytes"
+	"encoding/binary"
+	"fmt"
+	"strconv"
+	"strings"
+)
+
+type httpHeader []byte
+
+func (h httpHeader) ContentLength() int {
+	contentLength := -1
+	idx := bytes.Index(h, []byte("Content-Length: "))
+	if 0 <= idx {
+		_, err := fmt.Sscanf(string(h[idx+16:]), "%d", &contentLength)
+		if err != nil {
+			return -1
+		}
+	}
+	return contentLength
+}
+
+// TODO: IPAddress implementation should be moved under drivers/net
+// The same implementation exists in wifinina.
+type IPAddress []byte
+
+func (addr IPAddress) String() string {
+	if len(addr) < 4 {
+		return ""
+	}
+	return strconv.Itoa(int(addr[0])) + "." + strconv.Itoa(int(addr[1])) + "." + strconv.Itoa(int(addr[2])) + "." + strconv.Itoa(int(addr[3]))
+}
+
+func ParseIPv4(s string) (IPAddress, error) {
+	v := strings.Split(s, ".")
+	v0, _ := strconv.Atoi(v[0])
+	v1, _ := strconv.Atoi(v[1])
+	v2, _ := strconv.Atoi(v[2])
+	v3, _ := strconv.Atoi(v[3])
+	return IPAddress([]byte{byte(v0), byte(v1), byte(v2), byte(v3)}), nil
+}
+
+func (addr IPAddress) AsUint32() uint32 {
+	if len(addr) < 4 {
+		return 0
+	}
+	b := []byte(string(addr))
+	return binary.BigEndian.Uint32(b[0:4])
+}