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/* See LICENSE file for copyright and license details. */
#define IN_LIBGAMMA_QUARTZ_CG
#include "common.h"
/**
* Initialise an allocated partition state
*
* @param this The partition state to initialise
* @param site The site state for the site that the partition belongs to
* @param partition The the index of the partition within the site
* @return Zero on success, otherwise (negative) the value of an
* error identifier provided by this library
*/
int
libgamma_quartz_cg_partition_initialise(libgamma_partition_state_t *restrict this,
libgamma_site_state_t *restrict site, size_t partition)
{
CGDirectDisplayID *crtcs, *crtcs_old;
uint32_t cap = 4, n;
(void) site;
this->data = NULL;
if (partition)
return LIBGAMMA_NO_SUCH_PARTITION;
/* Allocate array of CRTC ID:s */
crtcs = malloc((size_t)cap * sizeof(CGDirectDisplayID));
if (!crtcs)
return LIBGAMMA_ERRNO_SET;
/* It is not possible to ask CoreGraphics how many CRTC:s are
* available. We have to ask it to give us a ID:s of a number
* of CRTC:s and ask for more if we got as many as we asked for. */
for (;;) {
/* Ask for CRTC ID:s */
if (CGGetOnlineDisplayList(cap, crtcs, &n) != kCGErrorSuccess)
return free(crtcs), LIBGAMMA_LIST_CRTCS_FAILED;
/* If we did not get as many as we asked for then we have all */
if (n < cap)
break;
/* Increase the number CRTC ID:s to ask for */
if (cap > UINT32_MAX / 2) /* We could also test ~0, but it is still too many */
return free(crtcs), LIBGAMMA_IMPOSSIBLE_AMOUNT;
cap <<= 1;
/* Grow the array of CRTC ID:s so that it can fit all we are asking for */
crtcs = realloc(crtcs_old = crtcs, (size_t)cap * sizeof(CGDirectDisplayID));
if (!crtcs) {
free(crtcs_old);
return LIBGAMMA_ERRNO_SET;
}
}
/* Store CRTC ID:s and CRTC count */
this->data = crtcs;
this->crtcs_available = (size_t)n;
return 0;
}
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