Add decimal_fast64_t pretty printer

Author: mborland

examples/debugger.cpp

@@ -43,6 +43,7 @@ int main()
     debug_values<boost::decimal::decimal128_t>();
 
     debug_values<boost::decimal::decimal_fast32_t>();
+    debug_values<boost::decimal::decimal_fast64_t>();
 
     return 0;
 }

extra/decimal_printer.py

@@ -6,6 +6,8 @@
 from detail.decode_ieee_type import decode_decimal64
 from detail.decode_ieee_type import decode_decimal128
 from detail.decode_fast_type import decode_decimal_fast32
+from detail.decode_fast_type import decode_decimal_fast64
+
 import lldb
 
 def decimal32_summary(valobj, internal_dict):
@@ -69,12 +71,29 @@ def decimal_fast32_summary(valobj, internal_dict):
     except Exception as e:
         return f"<invalid decimal_fast32_t: {e}>"
 
+def decimal_fast64_summary(valobj, internal_dict):
+    """
+    Custom summary for decimal_fast32_t type
+    Displays in scientific notation
+    """
+
+    try:
+        val = valobj.GetNonSyntheticValue()
+        significand = val.GetChildMemberWithName("significand_").GetValueAsUnsigned()
+        exp = val.GetChildMemberWithName("exponent_").GetValueAsUnsigned()
+        sign = val.GetChildMemberWithName("sign_").GetValueAsUnsigned()
+        return decode_decimal_fast64(significand, exp, sign)
+
+    except Exception as e:
+        return f"<invalid decimal_fast64_t: {e}>"
+
 def __lldb_init_module(debugger, internal_dict):
     decimal32_pattern = r"^(const )?(boost::decimal::decimal32_t|(\w+::)*decimal32_t)( &| \*)?$"
     decimal64_pattern = r"^(const )?(boost::decimal::decimal64_t|(\w+::)*decimal64_t)( &| \*)?$"
     decimal128_pattern = r"^(const )?(boost::decimal::decimal128_t|(\w+::)*decimal128_t)( &| \*)?$"
 
     decimal_fast32_pattern = r"^(const )?(boost::decimal::decimal_fast32_t|(\w+::)*decimal_fast32_t)( &| \*)?$"
+    decimal_fast64_pattern = r"^(const )?(boost::decimal::decimal_fast64_t|(\w+::)*decimal_fast64_t)( &| \*)?$"
 
     debugger.HandleCommand(
         f'type summary add -x "{decimal32_pattern}" -e -F decimal_printer.decimal32_summary'
@@ -112,6 +131,15 @@ def __lldb_init_module(debugger, internal_dict):
 
     print("decimal_fast32_t printer loaded successfully")
 
+    debugger.HandleCommand(
+        f'type summary add -x "{decimal_fast64_pattern}" -e -F decimal_printer.decimal_fast64_summary'
+    )
+    debugger.HandleCommand(
+        f'type synthetic add -x "{decimal_fast64_pattern}" -l decimal_printer.DecimalFastSyntheticProvider'
+    )
+
+    print("decimal_fast64_t printer loaded successfully")
+
 class DecimalSyntheticProvider:
     def __init__(self, valobj, internal_dict):
         self.valobj = valobj

extra/detail/decode_fast_type.py

@@ -35,3 +35,31 @@ def decode_decimal_fast32(significand, exp, sign):
         result = generate_string(significand, exp, sign)
 
     return result
+
+def decode_decimal_fast64(significand, exp, sign):
+
+    # See values of non-finite masks in decimal_fast32_t.hpp
+    if significand >= 2305843009213693952:
+        isnan = False
+
+        if significand == 2305843009213693952:
+            result = "-INF" if sign else "INF"
+        elif significand >= 16140901064495857664:
+            result = "-SNAN" if sign else "SNAN"
+            significand ^= 16140901064495857664
+            isnan = True
+        elif significand >= 6917529027641081856:
+            result = "-QNAN" if sign else "QNAN"
+            significand ^= 6917529027641081856
+            isnan = True
+        else:
+            raise ValueError("Unknown Finite Value")
+
+        if isnan and significand > 0:
+            result += '(' + str(significand) + ')'
+
+    else:
+        exp -= 398 # Bias value
+        result = generate_string(significand, exp, sign)
+
+    return result