Template specialization didnt work after addition of default constructor

Template specialization didn't work after addition of default constructor
for unsupported polynomials. Since the argument type and count are same,
compiler always selects the default constructor.

Author: deepikabhavnani

drivers/MbedCRC.cpp

@@ -24,46 +24,6 @@ namespace mbed {
 
 /* Default values for different types of polynomials
 */
-template<>
-MbedCRC<POLY_32BIT_ANSI, 32>::MbedCRC(uint32_t initial_xor, uint32_t final_xor, bool reflect_data, bool reflect_remainder):
-    _initial_value(initial_xor), _final_xor(final_xor), _reflect_data(reflect_data), _reflect_remainder(reflect_remainder),
-    _crc_table((uint32_t *)Table_CRC_32bit_ANSI)
-{
-    mbed_crc_ctor();
-}
-
-template<>
-MbedCRC<POLY_8BIT_CCITT, 8>::MbedCRC(uint32_t initial_xor, uint32_t final_xor, bool reflect_data, bool reflect_remainder):
-    _initial_value(initial_xor), _final_xor(final_xor), _reflect_data(reflect_data), _reflect_remainder(reflect_remainder),
-    _crc_table((uint32_t *)Table_CRC_8bit_CCITT)
-{
-    mbed_crc_ctor();
-}
-
-template<>
-MbedCRC<POLY_7BIT_SD, 7>::MbedCRC(uint32_t initial_xor, uint32_t final_xor, bool reflect_data, bool reflect_remainder):
-    _initial_value(initial_xor), _final_xor(final_xor), _reflect_data(reflect_data), _reflect_remainder(reflect_remainder),
-    _crc_table((uint32_t *)Table_CRC_7Bit_SD)
-{
-    mbed_crc_ctor();
-}
-
-template<>
-MbedCRC<POLY_16BIT_CCITT, 16>::MbedCRC(uint32_t initial_xor, uint32_t final_xor, bool reflect_data, bool reflect_remainder):
-    _initial_value(initial_xor), _final_xor(final_xor), _reflect_data(reflect_data), _reflect_remainder(reflect_remainder),
-    _crc_table((uint32_t *)Table_CRC_16bit_CCITT)
-{
-    mbed_crc_ctor();
-}
-
-template<>
-MbedCRC<POLY_16BIT_IBM, 16>::MbedCRC(uint32_t initial_xor, uint32_t final_xor, bool reflect_data, bool reflect_remainder):
-    _initial_value(initial_xor), _final_xor(final_xor), _reflect_data(reflect_data), _reflect_remainder(reflect_remainder),
-    _crc_table((uint32_t *)Table_CRC_16bit_IBM)
-{
-    mbed_crc_ctor();
-}
-
 template<>
 MbedCRC<POLY_32BIT_ANSI, 32>::MbedCRC():
     _initial_value(~(0x0)), _final_xor(~(0x0)), _reflect_data(true), _reflect_remainder(true),

drivers/MbedCRC.h

@@ -124,7 +124,7 @@ class MbedCRC {
      */
     MbedCRC(uint32_t initial_xor, uint32_t final_xor, bool reflect_data, bool reflect_remainder) :
         _initial_value(initial_xor), _final_xor(final_xor), _reflect_data(reflect_data),
-        _reflect_remainder(reflect_remainder), _crc_table(NULL)
+        _reflect_remainder(reflect_remainder)
     {
         mbed_crc_ctor();
     }
@@ -445,8 +445,6 @@ class MbedCRC {
     {
         MBED_STATIC_ASSERT(width <= 32, "Max 32-bit CRC supported");
 
-        _mode = (_crc_table != NULL) ? TABLE : BITWISE;
-
 #ifdef DEVICE_CRC
         crc_mbed_config_t config;
         config.polynomial  = polynomial;
@@ -458,8 +456,30 @@ class MbedCRC {
 
         if (hal_crc_is_supported(&config)) {
             _mode = HARDWARE;
+            return;
         }
 #endif
+        switch (polynomial) {
+            case POLY_32BIT_ANSI:
+                _crc_table = (uint32_t *)Table_CRC_32bit_ANSI;
+                break;
+            case POLY_8BIT_CCITT:
+                _crc_table = (uint32_t *)Table_CRC_8bit_CCITT;
+                break;
+            case POLY_7BIT_SD:
+                _crc_table = (uint32_t *)Table_CRC_7Bit_SD;
+                break;
+            case POLY_16BIT_CCITT:
+                _crc_table = (uint32_t *)Table_CRC_16bit_CCITT;
+                break;
+            case POLY_16BIT_IBM:
+                _crc_table = (uint32_t *)Table_CRC_16bit_IBM;
+                break;
+            default:
+                _crc_table = NULL;
+                break;
+        }
+        _mode = (_crc_table != NULL) ? TABLE : BITWISE;
     }
 };