AP_Baro: Change to secure code, from magic number to sizeof value.

libraries/AP_Baro/AP_Baro_BMP085.cpp

@@ -53,7 +53,7 @@ AP_Baro_BMP085::AP_Baro_BMP085(AP_Baro &baro, AP_HAL::OwnPtr<AP_HAL::I2CDevice>
     }
 
     // We read the calibration data registers
-    if (!_dev->read_registers(0xAA, buff, 22)) {
+    if (!_dev->read_registers(0xAA, buff, sizeof(buff))) {
         AP_HAL::panic("BMP085: bad calibration registers");
     }
 
@@ -140,7 +140,7 @@ bool AP_Baro_BMP085::_read_pressure()
 {
     uint8_t buf[3];
 
-    if (!_dev->read_registers(0xF6, buf, 3)) {
+    if (!_dev->read_registers(0xF6, buf, sizeof(buf))) {
         _retry_time = AP_HAL::millis() + 1000;
         _dev->set_speed(AP_HAL::Device::SPEED_LOW);
         return false;
@@ -165,7 +165,7 @@ void AP_Baro_BMP085::_read_temp()
     uint8_t buf[2];
     int32_t _temp_sensor;
 
-    if (!_dev->read_registers(0xF6, buf, 2)) {
+    if (!_dev->read_registers(0xF6, buf, sizeof(buf))) {
         _dev->set_speed(AP_HAL::Device::SPEED_LOW);
         return;
     }

libraries/AP_Baro/AP_Baro_MS5611.cpp

@@ -173,7 +173,7 @@ uint16_t AP_Baro_MS56XX::_read_prom_word(uint8_t word)
 {
     const uint8_t reg = CMD_MS56XX_PROM + (word << 1);
     uint8_t val[2];
-    if (!_dev->transfer(&reg, 1, val, 2)) {
+    if (!_dev->transfer(&reg, 1, val, sizeof(val))) {
         return 0;
     }
     return (val[0] << 8) | val[1];
@@ -182,7 +182,7 @@ uint16_t AP_Baro_MS56XX::_read_prom_word(uint8_t word)
 uint32_t AP_Baro_MS56XX::_read_adc()
 {
     uint8_t val[3];
-    if (!_dev->transfer(&CMD_MS56XX_READ_ADC, 1, val, 3)) {
+    if (!_dev->transfer(&CMD_MS56XX_READ_ADC, 1, val, sizeof(val))) {
         return 0;
     }
     return (val[0] << 16) | (val[1] << 8) | val[2];