Eliminate some compilation warnings.

1. Remove "pragma once" in cpp source file
2. Remove unused variables
3. Uninitialized variable initialization
4. Match the data types on both sides of the relational operator

Author: Wang DeYou

sdk/src/arch/linux/net_socket.cpp

@@ -435,7 +435,7 @@ class _single_thread StreamSocketImpl : public StreamSocket
     virtual u_result send(const void * buffer, size_t len) 
     {
         size_t ans = ::send( _socket_fd, buffer, len, MSG_NOSIGNAL);
-        if (ans == (int)len) {
+        if (ans == len) {
             return RESULT_OK;
         } else {
             switch (errno) {
@@ -719,7 +719,7 @@ class _single_thread DGramSocketImpl : public DGramSocket
 
     virtual u_result sendTo(const SocketAddress & target, const void * buffer, size_t len)
     {
-        const struct sockaddr* addr = &target ? reinterpret_cast<const struct sockaddr*>(target.getPlatformData()) : NULL;
+        const struct sockaddr* addr = reinterpret_cast<const struct sockaddr*>(target.getPlatformData());
         assert(addr);
         size_t ans = ::sendto( _socket_fd, buffer, len, 0, addr, sizeof(sockaddr_storage));
         if (ans != (size_t)-1) {

sdk/src/sl_crc.cpp

@@ -74,7 +74,7 @@ namespace sl {namespace crc32 {
         sl_u8 index;
         sl_u8* pch;
         pch = (unsigned char*)input;
-        sl_u8 leftBytes = 4 - len & 0x3;
+        sl_u8 leftBytes = (4 - len) & 0x3;
 
         for (i = 0; i < len; i++) {
             index = (unsigned char)(crc^*pch);

sdk/src/sl_lidar_driver.cpp

@@ -446,7 +446,7 @@ namespace sl {
             }
 
             //get scan answer type to specify how to wait data
-            sl_u8 scanAnsType;
+            sl_u8 scanAnsType = 0;
             if (ifSupportLidarConf) {
                 getScanModeAnsType(scanAnsType, scanMode);
             }
@@ -1068,7 +1068,6 @@ namespace sl {
 
         sl_result  _sendCommand(sl_u16 cmd, const void * payload = NULL, size_t payloadsize = 0 )
         {
-            sl_u8 pkt_header[10];
             sl_u8 checksum = 0;
 
             std::vector<sl_u8> cmd_packet;
@@ -1099,7 +1098,7 @@ namespace sl {
 
             }
             sl_u8 packet[1024];
-            for (int pos = 0; pos < cmd_packet.size(); pos++) {
+            for (sl_u32 pos = 0; pos < cmd_packet.size(); pos++) {
                 packet[pos] = cmd_packet[pos];
             }
             _channel->write(packet, cmd_packet.size());
@@ -1355,7 +1354,7 @@ namespace sl {
 
                     int dist_major2;
 
-                    sl_u32 scalelvl1, scalelvl2;
+                    sl_u32 scalelvl1 = 0, scalelvl2 = 0;
 
                     // prefetch next ...
                     if (pos == _countof(_cached_previous_ultracapsuledata.ultra_cabins) - 1) {

sdk/src/sl_serial_channel.cpp

@@ -30,7 +30,6 @@
   *
   */
 
-#pragma once
 #include "sl_lidar_driver.h"
 #include "hal/abs_rxtx.h"
 #include "hal/socket.h"

sdk/src/sl_tcp_channel.cpp

@@ -30,7 +30,6 @@
   *
   */
 
-#pragma once
 #include "sl_lidar_driver.h"
 #include "hal/abs_rxtx.h"
 #include "hal/socket.h"

sdk/src/sl_udp_channel.cpp

@@ -30,7 +30,6 @@
   *
   */
 
-#pragma once
 #include "sl_lidar_driver.h"
 #include "hal/abs_rxtx.h"
 #include "hal/socket.h"