Make most of functions const correct (#714)

* Make most of the functions const correct

Used clang-tidy and sonarlint to help find places where const could
pretty easily applied. Also lot of hand work.

This commit does not yet touch handlers and typedefs of those.

* Fix Arduino uno handler_who_is() has extra parenthesis

For some reason there is extra parenthesis. Remove it this is more
likely buildable.

* Bugfix/bacapp: Fix uninitilized array_index

We have changed bacapp_snprintf_value() to be const correct. After that
we got

```
/home/runner/work/bacnet-stack/bacnet-stack/src/bacnet/bacapp.c:3183:27: warning: 4th function call argument is an uninitialized value [core.CallAndMessage]
                ret_val = bacapp_snprintf_weeklyschedule(
                          ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
1 warning generated.
```

So analyzer could now spot that we do not actually initilize array_index
at all. Fix this by setting array_index to zero. Note that I actually do
not know if zeroing is right thing to do here. I choose zero as if this
has worked before it is most likely that it will work with zero value.

* cmake: Add and ignore Wwrite-strings compiler option

Wwrite-strings helps find places where const correctness is broken.

Example it will warn about these

```C

void func1(char* str);

func("test") /* "test" is const so we should not pass it to func1().

char* func2()
{
  return "test"; /* func2() should return const char*.
}
```

We still need to ignore it as not all are fixed but let's add it already
so we remember that it should be opened at some point.

---------

Co-authored-by: Kari Argillander <kari.argillander@fidelix.com>

ports/arduino_uno/bip-init.c

@@ -50,7 +50,7 @@ long bip_getaddrbyname(const char *host_name)
  * @param ifname [in] The named interface to use for the network layer.
  *        Eg, for Linux, ifname is eth0, ath0, arc0, and others.
  */
-void bip_set_interface(char *ifname)
+void bip_set_interface(const char *ifname)
 {
     uint8_t local_address[] = { 0, 0, 0, 0 };
     uint8_t broadcast_address[] = { 0, 0, 0, 0 };

ports/arduino_uno/bip.c

@@ -34,7 +34,7 @@ static uint8_t BIP_Broadcast_Address[4] = { 0, 0, 0, 0 };
 /** Converter from uint8_t[4] type address to uint32_t
  *
  */
-uint32_t convertBIP_Address2uint32(uint8_t *bip_address)
+uint32_t convertBIP_Address2uint32(const suint8_t *bip_address)
 {
     return (uint32_t)((bip_address[0] * 2 ^ 24) + (bip_address[1] * 2 ^ 16) +
         (bip_address[2] * 2 ^ 8) + bip_address[3]);
@@ -74,7 +74,7 @@ bool bip_valid(void)
     return (BIP_Socket < MAX_SOCK_NUM);
 }
 
-void bip_set_addr(uint8_t *net_address)
+void bip_set_addr(const uint8_t *net_address)
 { /* in network byte order */
     for (uint8_t i = 0; i < 4; i++)
         BIP_Address[i] = net_address[i];
@@ -86,7 +86,7 @@ uint8_t *bip_get_addr(void)
     return BIP_Address;
 }
 
-void bip_set_broadcast_addr(uint8_t *net_address)
+void bip_set_broadcast_addr(const uint8_t *net_address)
 { /* in network byte order */
     for (uint8_t i = 0; i < 4; i++)
         BIP_Broadcast_Address[i] = net_address[i];
@@ -109,9 +109,8 @@ uint16_t bip_get_port(void)
     return ntohs(BIP_Port);
 }
 
-static int bip_decode_bip_address(BACNET_ADDRESS *bac_addr,
+static int bip_decode_bip_address(const BACNET_ADDRESS *bac_addr,
     uint8_t *address, /* in network format */
-
     uint16_t *port)
 { /* in network format */
     int len = 0;

ports/arduino_uno/bip.h

@@ -28,11 +28,11 @@ extern "C" {
     /* on Linux, ifname is eth0, ath0, arc0, and others.
        on Windows, ifname is the dotted ip address of the interface */
     bool bip_init(char *ifname);
-    void bip_set_interface(char *ifname);
+    void bip_set_interface(const char *ifname);
     void bip_cleanup(void);
 
     /* Convert uint8_t IPv4 to uint32 */
-    uint32_t convertBIP_Address2uint32(uint8_t * bip_address);
+    uint32_t convertBIP_Address2uint32(const uint8_t * bip_address);
     void convertUint32Address_2_uint8Address(uint32_t ip,
         uint8_t * address);
     /* common BACnet/IP functions */
@@ -68,12 +68,12 @@ extern "C" {
     uint16_t bip_get_port(void);
 
     /* use network byte order for setting */
-    void bip_set_addr(uint8_t * net_address);
+    void bip_set_addr(const uint8_t * net_address);
     /* returns network byte order */
     uint8_t *bip_get_addr(void);
 
     /* use network byte order for setting */
-    void bip_set_broadcast_addr(uint8_t * net_address);
+    void bip_set_broadcast_addr(const uint8_t * net_address);
     /* returns network byte order */
     uint8_t *bip_get_broadcast_addr(void);
 

ports/arduino_uno/bvlc-arduino.c

@@ -54,12 +54,9 @@ static int bvlc_encode_bvlc_result(uint8_t *pdu, BACNET_BVLC_RESULT result_code)
  * @return Upon successful completion, returns the number of bytes sent.
  *  Otherwise, -1 shall be returned and errno set to indicate the error.
  */
-static int bvlc_send_mpdu(uint8_t *dest_addr, /* the destination address */
-
-    uint16_t *dest_port, /* the destination port */
-
+static int bvlc_send_mpdu(const uint8_t *dest_addr, /* the destination address */
+    const uint16_t *dest_port, /* the destination port */
     uint8_t *mtu, /* the data */
-
     uint16_t mtu_len)
 { /* amount of data to send  */
     /* assumes that the driver has already been initialized */
@@ -75,9 +72,8 @@ static int bvlc_send_mpdu(uint8_t *dest_addr, /* the destination address */
  * @param dest_addr - destination address
  * @param dest_port - destination port
  */
-static void bvlc_send_result(uint8_t *dest_addr,
-    uint16_t *dest_port, /* the destination address */
-
+static void bvlc_send_result(const uint8_t *dest_addr,
+    const uint16_t *dest_port, /* the destination address */
     BACNET_BVLC_RESULT result_code)
 {
     uint8_t mtu[BIP_MPDU_MAX] = { 0 };

ports/arduino_uno/h_whois.c

@@ -64,7 +64,7 @@ void handler_who_is(
     } else if (len != -1) {
         /* is my device id within the limits? */
         target_device = Device_Object_Instance_Number();
-        if (((target_device >= low_limit) && (target_device <= high_limit)) {
+        if ((target_device >= low_limit) && (target_device <= high_limit)) {
             sendIamUnicast(&Handler_Transmit_Buffer[0], src);
         }
     }