mfbt/IntegerPrintfMacros.h

   1 /* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
   2 /* vim: set ts=8 sts=2 et sw=2 tw=80: */
   3 /* This Source Code Form is subject to the terms of the Mozilla Public
   4  * License, v. 2.0. If a copy of the MPL was not distributed with this
   5  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
   6
   7 /* Implements the C99 <inttypes.h> interface, minus the SCN* format macros. */
   8
   9 #ifndef mozilla_IntegerPrintfMacros_h_
  10 #define mozilla_IntegerPrintfMacros_h_
  11
  12 /*
  13  * MSVC++ doesn't include <inttypes.h>, even in versions shipping <stdint.h>, so
  14  * we have to reimplement it there.  Note: <inttypes.h> #includes <stdint.h>.
  15  *
  16  * Note that this header DOES NOT implement <inttypes.h>'s scanf macros.  MSVC's
  17  * scanf doesn't have sufficient format specifier support to implement them
  18  * (specifically, to implement scanning into an 8-bit location).
  19  *
  20  * http://stackoverflow.com/questions/3036396/scanfd-char-char-as-int-format-string
  21  *
  22  * Moreover, scanf is a footgun: if the input number exceeds the bounds of the
  23  * target type, behavior is undefined (in the compiler sense: that is, this code
  24  * could overwrite your hard drive with zeroes):
  25  *
  26  *   uint8_t u;
  27  *   sscanf("256", "%" SCNu8, &u); // BAD
  28  *
  29  * This header will sometimes provide SCN* macros, by dint of being implemented
  30  * using <inttypes.h>.  But for these reasons, *never* use them!
  31  */
  32
  33 #if defined(MOZ_CUSTOM_INTTYPES_H)
  34 #  include MOZ_CUSTOM_INTTYPES_H
  35 #elif defined(_MSC_VER)
  36 #  include "mozilla/MSIntTypes.h"
  37 #else
  38 #  include <inttypes.h>
  39 #endif
  40
  41 /*
  42  * Fix up Android's broken [u]intptr_t inttype macros. Android's PRI*PTR
  43  * macros are defined as "ld", but sizeof(long) is 8 and sizeof(intptr_t)
  44  * is 4 on 32-bit Android. TestTypeTraits.cpp asserts that these new macro
  45  * definitions match the actual type sizes seen at compile time.
  46  */
  47 #if defined(ANDROID) && !defined(__LP64__)
  48 #  undef  PRIdPTR      /* intptr_t  */
  49 #  define PRIdPTR "d"  /* intptr_t  */
  50 #  undef  PRIiPTR      /* intptr_t  */
  51 #  define PRIiPTR "i"  /* intptr_t  */
  52 #  undef  PRIoPTR      /* uintptr_t */
  53 #  define PRIoPTR "o"  /* uintptr_t */
  54 #  undef  PRIuPTR      /* uintptr_t */
  55 #  define PRIuPTR "u"  /* uintptr_t */
  56 #  undef  PRIxPTR      /* uintptr_t */
  57 #  define PRIxPTR "x"  /* uintptr_t */
  58 #  undef  PRIXPTR      /* uintptr_t */
  59 #  define PRIXPTR "X"  /* uintptr_t */
  60 #endif
  61
  62 /**
  63  * For printing size_t.
  64  */
  65 #define PRIuSIZE PRIuPTR
  66
  67 #endif  /* mozilla_IntegerPrintfMacros_h_ */