1 files changed, 270 insertions, 0 deletions
diff --git a/src/miasm/core/modint.py b/src/miasm/core/modint.py
new file mode 100644
index 00000000..14b4dc2c
--- /dev/null
+++ b/src/miasm/core/modint.py
@@ -0,0 +1,270 @@
+#-*- coding:utf-8 -*-
+
+from builtins import range
+from functools import total_ordering
+
+@total_ordering
+class moduint(object):
+
+    def __init__(self, arg):
+        self.arg = int(arg) % self.__class__.limit
+        assert(self.arg >= 0 and self.arg < self.__class__.limit)
+
+    def __repr__(self):
+        return self.__class__.__name__ + '(' + hex(self.arg) + ')'
+
+    def __hash__(self):
+        return hash(self.arg)
+
+    @classmethod
+    def maxcast(cls, c2):
+        c2 = c2.__class__
+        if cls.size > c2.size:
+            return cls
+        else:
+            return c2
+
+    def __eq__(self, y):
+        if isinstance(y, moduint):
+            return self.arg == y.arg
+        return self.arg == y
+
+    def __ne__(self, y):
+        # required Python 2.7.14
+        return not self == y
+
+    def __lt__(self, y):
+        if isinstance(y, moduint):
+            return self.arg < y.arg
+        return self.arg < y
+
+    def __add__(self, y):
+        if isinstance(y, moduint):
+            cls = self.maxcast(y)
+            return cls(self.arg + y.arg)
+        else:
+            return self.__class__(self.arg + y)
+
+    def __and__(self, y):
+        if isinstance(y, moduint):
+            cls = self.maxcast(y)
+            return cls(self.arg & y.arg)
+        else:
+            return self.__class__(self.arg & y)
+
+    def __div__(self, y):
+        # Python: 8 / -7 == -2 (C-like: -1)
+        # int(float) trick cannot be used, due to information loss
+        # Examples:
+        #
+        # 42 / 10 => 4
+        # 42 % 10 => 2
+        #
+        # -42 / 10 => -4
+        # -42 % 10 => -2
+        #
+        # 42 / -10 => -4
+        # 42 % -10 => 2
+        #
+        # -42 / -10 => 4
+        # -42 % -10 => -2
+
+        den = int(y)
+        num = int(self)
+        result_sign = 1 if (den * num) >= 0 else -1
+        cls = self.__class__
+        if isinstance(y, moduint):
+            cls = self.maxcast(y)
+        return (abs(num) // abs(den)) * result_sign
+
+    def __floordiv__(self, y):
+        return self.__div__(y)
+
+    def __int__(self):
+        return int(self.arg)
+
+    def __long__(self):
+        return int(self.arg)
+
+    def __index__(self):
+        return int(self.arg)
+
+    def __invert__(self):
+        return self.__class__(~self.arg)
+
+    def __lshift__(self, y):
+        if isinstance(y, moduint):
+            cls = self.maxcast(y)
+            return cls(self.arg << y.arg)
+        else:
+            return self.__class__(self.arg << y)
+
+    def __mod__(self, y):
+        # See __div__ for implementation choice
+        cls = self.__class__
+        if isinstance(y, moduint):
+            cls = self.maxcast(y)
+        return cls(self.arg - y * (self // y))
+
+    def __mul__(self, y):
+        if isinstance(y, moduint):
+            cls = self.maxcast(y)
+            return cls(self.arg * y.arg)
+        else:
+            return self.__class__(self.arg * y)
+
+    def __neg__(self):
+        return self.__class__(-self.arg)
+
+    def __or__(self, y):
+        if isinstance(y, moduint):
+            cls = self.maxcast(y)
+            return cls(self.arg | y.arg)
+        else:
+            return self.__class__(self.arg | y)
+
+    def __radd__(self, y):
+        return self.__add__(y)
+
+    def __rand__(self, y):
+        return self.__and__(y)
+
+    def __rdiv__(self, y):
+        if isinstance(y, moduint):
+            cls = self.maxcast(y)
+            return cls(y.arg // self.arg)
+        else:
+            return self.__class__(y // self.arg)
+
+    def __rfloordiv__(self, y):
+        return self.__rdiv__(y)
+
+    def __rlshift__(self, y):
+        if isinstance(y, moduint):
+            cls = self.maxcast(y)
+            return cls(y.arg << self.arg)
+        else:
+            return self.__class__(y << self.arg)
+
+    def __rmod__(self, y):
+        if isinstance(y, moduint):
+            cls = self.maxcast(y)
+            return cls(y.arg % self.arg)
+        else:
+            return self.__class__(y % self.arg)
+
+    def __rmul__(self, y):
+        return self.__mul__(y)
+
+    def __ror__(self, y):
+        return self.__or__(y)
+
+    def __rrshift__(self, y):
+        if isinstance(y, moduint):
+            cls = self.maxcast(y)
+            return cls(y.arg >> self.arg)
+        else:
+            return self.__class__(y >> self.arg)
+
+    def __rshift__(self, y):
+        if isinstance(y, moduint):
+            cls = self.maxcast(y)
+            return cls(self.arg >> y.arg)
+        else:
+            return self.__class__(self.arg >> y)
+
+    def __rsub__(self, y):
+        if isinstance(y, moduint):
+            cls = self.maxcast(y)
+            return cls(y.arg - self.arg)
+        else:
+            return self.__class__(y - self.arg)
+
+    def __rxor__(self, y):
+        return self.__xor__(y)
+
+    def __sub__(self, y):
+        if isinstance(y, moduint):
+            cls = self.maxcast(y)
+            return cls(self.arg - y.arg)
+        else:
+            return self.__class__(self.arg - y)
+
+    def __xor__(self, y):
+        if isinstance(y, moduint):
+            cls = self.maxcast(y)
+            return cls(self.arg ^ y.arg)
+        else:
+            return self.__class__(self.arg ^ y)
+
+    def __hex__(self):
+        return hex(self.arg)
+
+    def __abs__(self):
+        return abs(self.arg)
+
+    def __rpow__(self, v):
+        return v ** self.arg
+
+    def __pow__(self, v):
+        return self.__class__(self.arg ** v)
+
+
+class modint(moduint):
+
+    def __init__(self, arg):
+        if isinstance(arg, moduint):
+            arg = arg.arg
+        a = arg % self.__class__.limit
+        if a >= self.__class__.limit // 2:
+            a -= self.__class__.limit
+        self.arg = a
+        assert(
+            self.arg >= -self.__class__.limit // 2 and
+            self.arg < self.__class__.limit
+        )
+
+
+def is_modint(a):
+    return isinstance(a, moduint)
+
+
+mod_size2uint = {}
+mod_size2int = {}
+
+mod_uint2size = {}
+mod_int2size = {}
+
+def define_int(size):
+    """Build the 'modint' instance corresponding to size @size"""
+    global mod_size2int, mod_int2size
+
+    name = 'int%d' % size
+    cls = type(name, (modint,), {"size": size, "limit": 1 << size})
+    globals()[name] = cls
+    mod_size2int[size] = cls
+    mod_int2size[cls] = size
+    return cls
+
+def define_uint(size):
+    """Build the 'moduint' instance corresponding to size @size"""
+    global mod_size2uint, mod_uint2size
+
+    name = 'uint%d' % size
+    cls = type(name, (moduint,), {"size": size, "limit": 1 << size})
+    globals()[name] = cls
+    mod_size2uint[size] = cls
+    mod_uint2size[cls] = size
+    return cls
+
+def define_common_int():
+    "Define common int"
+    common_int = range(1, 257)
+
+    for i in common_int:
+        define_int(i)
+
+    for i in common_int:
+        define_uint(i)
+
+define_common_int()