diff options
Diffstat (limited to 'os.c')
| -rw-r--r-- | os.c | 43 |
1 files changed, 26 insertions, 17 deletions
@@ -1,5 +1,5 @@ /* - * Copyright (C) 1984-2009 Mark Nudelman + * Copyright (C) 1984-2011 Mark Nudelman * * You may distribute under the terms of either the GNU General Public * License or the Less License, as specified in the README file. @@ -250,6 +250,28 @@ errno_message(filename) return (m); } +/* #define HAVE_FLOAT 0 */ + + static POSITION +muldiv(val, num, den) + POSITION val, num, den; +{ +#if HAVE_FLOAT + double v = (((double) val) * num) / den; + return ((POSITION) (v + 0.5)); +#else + POSITION v = ((POSITION) val) * num; + + if (v / num == val) + /* No overflow */ + return (POSITION) (v / den); + else + /* Above calculation overflows; + * use a method that is less precise but won't overflow. */ + return (POSITION) (val / (den / num)); +#endif +} + /* * Return the ratio of two POSITIONS, as a percentage. * {{ Assumes a POSITION is a long int. }} @@ -258,12 +280,7 @@ errno_message(filename) percentage(num, den) POSITION num, den; { - POSITION num100 = num * 100; - - if (num100 / 100 == num) - return (num100 / den); - else - return (num / (den / 100)); + return (int) muldiv(num, (POSITION) 100, den); } /* @@ -276,19 +293,11 @@ percent_pos(pos, percent, fraction) long fraction; { /* Change percent (parts per 100) to perden (parts per NUM_FRAC_DENOM). */ - long perden = (percent * (NUM_FRAC_DENOM / 100)) + (fraction / 100); - POSITION temp; + POSITION perden = (percent * (NUM_FRAC_DENOM / 100)) + (fraction / 100); if (perden == 0) return (0); - temp = pos * perden; /* This might overflow. */ - if (temp / perden == pos) - /* No overflow */ - return (temp / NUM_FRAC_DENOM); - else - /* Above calculation overflows; - * use a method that is less precise but won't overflow. */ - return (perden * (pos / NUM_FRAC_DENOM)); + return (POSITION) muldiv(pos, perden, (POSITION) NUM_FRAC_DENOM); } #if !HAVE_STRCHR |