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intprops.h 2.6 KB

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  1. /* intprops.h -- properties of integer types
  2. Copyright (C) 2001, 2002, 2003, 2004, 2005 Free Software Foundation, Inc.
  3. This program is free software; you can redistribute it and/or modify
  4. it under the terms of the GNU General Public License as published by
  5. the Free Software Foundation; either version 2, or (at your option)
  6. any later version.
  7. This program is distributed in the hope that it will be useful,
  8. but WITHOUT ANY WARRANTY; without even the implied warranty of
  9. MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  10. GNU General Public License for more details.
  11. You should have received a copy of the GNU General Public License
  12. along with this program; if not, write to the Free Software Foundation,
  13. Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. */
  14. /* Written by Paul Eggert. */
  15. #include <limits.h>
  16. /* The extra casts in the following macros work around compiler bugs,
  17. e.g., in Cray C 5.0.3.0. */
  18. /* True if the arithmetic type T is an integer type. bool counts as
  19. an integer. */
  20. #define TYPE_IS_INTEGER(t) ((t) 1.5 == 1)
  21. /* True if negative values of the signed integer type T use two's
  22. complement, ones' complement, or signed magnitude representation,
  23. respectively. Much GNU code assumes two's complement, but some
  24. people like to be portable to all possible C hosts. */
  25. #define TYPE_TWOS_COMPLEMENT(t) ((t) ~ (t) 0 == (t) -1)
  26. #define TYPE_ONES_COMPLEMENT(t) ((t) ~ (t) 0 == 0)
  27. #define TYPE_SIGNED_MAGNITUDE(t) ((t) ~ (t) 0 < (t) -1)
  28. /* True if the arithmetic type T is signed. */
  29. #define TYPE_SIGNED(t) (! ((t) 0 < (t) -1))
  30. /* The maximum and minimum values for the integer type T. These
  31. macros have undefined behavior if T is signed and has padding bits.
  32. If this is a problem for you, please let us know how to fix it for
  33. your host. */
  34. #define TYPE_MINIMUM(t) \
  35. ((t) (! TYPE_SIGNED (t) \
  36. ? (t) 0 \
  37. : TYPE_SIGNED_MAGNITUDE (t) \
  38. ? ~ (t) 0 \
  39. : ~ (t) 0 << (sizeof (t) * CHAR_BIT - 1)))
  40. #define TYPE_MAXIMUM(t) \
  41. ((t) (! TYPE_SIGNED (t) \
  42. ? (t) -1 \
  43. : ~ (~ (t) 0 << (sizeof (t) * CHAR_BIT - 1))))
  44. /* Bound on length of the string representing an integer type or expression T.
  45. Subtract 1 for the sign bit if t is signed; log10 (2.0) < 146/485;
  46. add 1 for integer division truncation; add 1 more for a minus sign
  47. if needed. */
  48. #define INT_STRLEN_BOUND(t) \
  49. ((sizeof (t) * CHAR_BIT - 1) * 146 / 485 + 2)
  50. /* Bound on buffer size needed to represent an integer type or expression T,
  51. including the terminating null. */
  52. #define INT_BUFSIZE_BOUND(t) (INT_STRLEN_BOUND (t) + 1)