utils: gdb: add BigNum pretty printer

utils/gdb/abacus_pretty_printers.py

@@ -0,0 +1,30 @@
+import gdb.printing
+
+class BigNumPrinter(object):
+    "Print a abacus::bignum::BigNum"
+
+    def __init__(self, val):
+        self.val = val
+
+    def to_string(self):
+        digits = self.val['digits_']
+        begin, end = digits['_M_impl']['_M_start'], digits['_M_impl']['_M_finish']
+        val = 0
+        while begin != end:
+            val *= 10
+            val += begin.dereference()
+            begin += 1
+        val *= self.val['sign_']
+        return str(val)
+
+    def display_hint(self):
+        return 'string'
+
+def build_pretty_printer():
+    pp = gdb.printing.RegexpCollectionPrettyPrinter('abacus')
+
+    pp.add_printer('BigNum', '^abacus::bignum::BigNum$', BigNumPrinter)
+
+    return pp
+
+gdb.printing.register_pretty_printer(gdb.current_objfile(), build_pretty_printer(), True)