Mercurial > hg > octave-lyh > gnulib-hg
changeset 6308:85c77359638b
(signed_type_or_expr__): Define.
(INT_STRLEN_BOUND) [__GNUC__]: Use a slightly tighter bound
for unsigned types.
author | Jim Meyering <jim@meyering.net> |
---|---|
date | Tue, 27 Sep 2005 08:40:36 +0000 |
parents | 40c7a4f520ed |
children | c1eccf76eb82 |
files | lib/intprops.h |
diffstat | 1 files changed, 15 insertions(+), 2 deletions(-) [+] |
line wrap: on
line diff
--- a/lib/intprops.h +++ b/lib/intprops.h @@ -53,12 +53,25 @@ ? (t) -1 \ : ~ (~ (t) 0 << (sizeof (t) * CHAR_BIT - 1)))) +/* Return zero if T can be determined to be an unsigned type. + Otherwise, return 1. + When compiling with GCC, INT_STRLEN_BOUND uses this macro to obtain a + tighter bound. Otherwise, it overestimates the true bound by one byte + when applied to unsigned types of size 2, 4, 16, ... bytes. + The symbol signed_type_or_expr__ is private to this header file. */ +#if __GNUC__ >= 2 +# define signed_type_or_expr__(t) TYPE_SIGNED (__typeof__ (t)) +#else +# define signed_type_or_expr__(t) 1 +#endif + /* Bound on length of the string representing an integer type or expression T. - Subtract 1 for the sign bit if t is signed; log10 (2.0) < 146/485; + Subtract 1 for the sign bit if T is signed; log10 (2.0) < 146/485; add 1 for integer division truncation; add 1 more for a minus sign if needed. */ #define INT_STRLEN_BOUND(t) \ - ((sizeof (t) * CHAR_BIT - 1) * 146 / 485 + 2) + ((sizeof (t) * CHAR_BIT - signed_type_or_expr__ (t)) * 146 / 485 \ + + signed_type_or_expr__ (t) + 1) /* Bound on buffer size needed to represent an integer type or expression T, including the terminating null. */