def _parse_constant()

in functions/source/generateAemSslCertificate/cffi/cparser.py [0:0]

• 64 lines of code
• 35 McCabe index (conditional complexity)

    def _parse_constant(self, exprnode, partial_length_ok=False):
        # for now, limited to expressions that are an immediate number
        # or positive/negative number
        if isinstance(exprnode, pycparser.c_ast.Constant):
            s = exprnode.value
            if '0' <= s[0] <= '9':
                s = s.rstrip('uUlL')
                try:
                    if s.startswith('0'):
                        return int(s, 8)
                    else:
                        return int(s, 10)
                except ValueError:
                    if len(s) > 1:
                        if s.lower()[0:2] == '0x':
                            return int(s, 16)
                        elif s.lower()[0:2] == '0b':
                            return int(s, 2)
                raise CDefError("invalid constant %r" % (s,))
            elif s[0] == "'" and s[-1] == "'" and (
                    len(s) == 3 or (len(s) == 4 and s[1] == "\\")):
                return ord(s[-2])
            else:
                raise CDefError("invalid constant %r" % (s,))
        #
        if (isinstance(exprnode, pycparser.c_ast.UnaryOp) and
                exprnode.op == '+'):
            return self._parse_constant(exprnode.expr)
        #
        if (isinstance(exprnode, pycparser.c_ast.UnaryOp) and
                exprnode.op == '-'):
            return -self._parse_constant(exprnode.expr)
        # load previously defined int constant
        if (isinstance(exprnode, pycparser.c_ast.ID) and
                exprnode.name in self._int_constants):
            return self._int_constants[exprnode.name]
        #
        if (isinstance(exprnode, pycparser.c_ast.ID) and
                    exprnode.name == '__dotdotdotarray__'):
            if partial_length_ok:
                self._partial_length = True
                return '...'
            raise FFIError(":%d: unsupported '[...]' here, cannot derive "
                           "the actual array length in this context"
                           % exprnode.coord.line)
        #
        if isinstance(exprnode, pycparser.c_ast.BinaryOp):
            left = self._parse_constant(exprnode.left)
            right = self._parse_constant(exprnode.right)
            if exprnode.op == '+':
                return left + right
            elif exprnode.op == '-':
                return left - right
            elif exprnode.op == '*':
                return left * right
            elif exprnode.op == '/':
                return self._c_div(left, right)
            elif exprnode.op == '%':
                return left - self._c_div(left, right) * right
            elif exprnode.op == '<<':
                return left << right
            elif exprnode.op == '>>':
                return left >> right
            elif exprnode.op == '&':
                return left & right
            elif exprnode.op == '|':
                return left | right
            elif exprnode.op == '^':
                return left ^ right
        #
        raise FFIError(":%d: unsupported expression: expected a "
                       "simple numeric constant" % exprnode.coord.line)