diff options
Diffstat (limited to 'util.c')
| -rw-r--r-- | util.c | 38 |
1 files changed, 38 insertions, 0 deletions
@@ -1223,3 +1223,41 @@ void fsync_pcap_and_log(void) if (log_file != -1) (void)fsync(log_file); } + +/** + * clamped_scale() - Scale @x from 100% to f% depending on @y's value + * @x: Value to scale + * @y: Value determining scaling + * @lo: Lower bound for @y (start of y-axis slope) + * @hi: Upper bound for @y (end of y-axis slope) + * @f: Scaling factor, percent (might be less or more than 100) + * + * Return: @x scaled by @f * linear interpolation of @y between @lo and @hi + * + * In pictures: + * + * f % -> ,---- * If @y < lo (for example, @y is y0), return @x + * /| | + * / | | * If @lo < @y < @hi (for example, @y is y1), + * / | | return @x scaled by a factor linearly + * (100 + f) / 2 % ->/ | | interpolated between 100% and f% depending on + * /| | | @y's position between @lo (100%) and @hi (f%) + * / | | | + * / | | | * If @y > @hi (for example, @y is y2), return + * 100 % -> -----' | | | @x * @f / 100 + * | | | | | + * y0 lo y1 hi y2 Example: @f = 150, @lo = 10, @hi = 20, @y = 15, + * @x = 1000 + * -> interpolated factor is 125% + * -> return 1250 + */ +long clamped_scale(long x, long y, long lo, long hi, long f) +{ + if (y < lo) + return x; + + if (y > hi) + return x * f / 100; + + return x - (x * (y - lo) / (hi - lo)) * (100 - f) / 100; +} |