hphp/util/safe-cast.h

   1 /*
   2    +----------------------------------------------------------------------+
   3    | HipHop for PHP                                                       |
   4    +----------------------------------------------------------------------+
   5    | Copyright (c) 2010-present Facebook, Inc. (http://www.facebook.com)  |
   6    +----------------------------------------------------------------------+
   7    | This source file is subject to version 3.01 of the PHP license,      |
   8    | that is bundled with this package in the file LICENSE, and is        |
   9    | available through the world-wide-web at the following url:           |
  10    | http://www.php.net/license/3_01.txt                                  |
  11    | If you did not receive a copy of the PHP license and are unable to   |
  12    | obtain it through the world-wide-web, please send a note to          |
  13    | license@php.net so we can mail you a copy immediately.               |
  14    +----------------------------------------------------------------------+
  15 */
  16 #pragma once
  17
  18 #include <string>
  19 #include <boost/numeric/conversion/cast.hpp>
  20
  21 #include <folly/Conv.h>
  22
  23 #include "hphp/util/compilation-flags.h"
  24 #include "hphp/util/portability.h"
  25
  26 namespace HPHP {
  27
  28 //////////////////////////////////////////////////////////////////////
  29
  30 [[noreturn]]
  31 void safe_cast_failure(const std::string&, const char*, const char*);
  32
  33 //////////////////////////////////////////////////////////////////////
  34
  35 /*
  36  * Optionally DEBUG-only wrappers around boost::numeric_cast that convert any
  37  * thrown exceptions to a failed assertion.
  38  */
  39
  40 template<typename To, typename From>
  41 To always_safe_cast(From val) {
  42   try {
  43     return boost::numeric_cast<To>(val);
  44   } catch (std::bad_cast& bce) {
  45     safe_cast_failure(
  46       folly::to<std::string>(val),
  47       // The function is always safe_cast, but will indicate which
  48       // types were involved.
  49       __PRETTY_FUNCTION__,
  50       bce.what()
  51     );
  52   }
  53 }
  54
  55 template<typename To, typename From>
  56 To safe_cast(From val) {
  57   return debug ? always_safe_cast<To>(val) : static_cast<To>(val);
  58 }
  59
  60 //////////////////////////////////////////////////////////////////////
  61
  62 }
  63