/* Bound an image to have a width between wmin and wmax, and height between
* hmin and hmax, inclusive. Additionally, the width will be a multiple of
* 2^walign, the height will be a multiple of 2^halign, and the overall size
* (width*height) will be a multiple of 2^salign. The image may be shrunk
* or enlarged to fit the alignment constraints.
*
* The width or height maximum must not be smaller than the corresponding
* minimum. The alignments must not be so high there are no possible image
* sizes within the allowed bounds. wmin and hmin must be at least 1
* (don't use 0). If you don't care about a certain alignment, specify 0,
* as 2^0 is 1 and one byte alignment is equivalent to no alignment. If
* you only want to adjust downward, specify a maximum that's the same as
* the initial value.
*/
void v4l_bound_align_image(u32 *w, unsigned int wmin, unsigned int wmax,
unsigned int walign,
u32 *h, unsigned int hmin, unsigned int hmax,
unsigned int halign, unsigned int salign)
{
*w = clamp_align(*w, wmin, wmax, walign);
*h = clamp_align(*h, hmin, hmax, halign);
/* Usually we don't need to align the size and are done now. */
if (!salign)
return;
/* How much alignment do we have? */
walign = __ffs(*w);
halign = __ffs(*h);
/* Enough to satisfy the image alignment? */
if (walign + halign < salign) {
/* Max walign where there is still a valid width */
unsigned int wmaxa = __fls(wmax ^ (wmin - 1));
/* Max halign where there is still a valid height */
unsigned int hmaxa = __fls(hmax ^ (hmin - 1));
/* up the smaller alignment until we have enough */
do {
if (halign >= hmaxa ||
(walign <= halign && walign < wmaxa)) {
*w = clamp_align(*w, wmin, wmax, walign + 1);
walign = __ffs(*w);
} else {
*h = clamp_align(*h, hmin, hmax, halign + 1);
halign = __ffs(*h);
}
} while (halign + walign < salign);
}
}
void v4l_bound_align_image(u32 *w, unsigned int wmin, unsigned int wmax,
unsigned int walign,
u32 *h, unsigned int hmin, unsigned int hmax,
unsigned int halign, unsigned int salign)
{
*w = clamp_align(*w, wmin, wmax, walign);
*h = clamp_align(*h, hmin, hmax, halign);
if (!salign)
return;
walign = __ffs(*w);
halign = __ffs(*h);
if (walign + halign < salign) {
unsigned int wmaxa = __fls(wmax ^ (wmin - 1));
unsigned int hmaxa = __fls(hmax ^ (hmin - 1));
do {
if (halign >= hmaxa ||
(walign <= halign && walign < wmaxa)) {
*w = clamp_align(*w, wmin, wmax, walign + 1);
walign = __ffs(*w);
} else {
*h = clamp_align(*h, hmin, hmax, halign + 1);
halign = __ffs(*h);
}
} while (halign + walign < salign);
}
}