#508 null pointer in segment.c

[BlueKiller]

Here is the critical code:

…
  root=MagickAllocateMemory(IntervalTree *,sizeof(IntervalTree)); //1198
  root->child=(IntervalTree *) NULL;
  root->sibling=(IntervalTree *) NULL;
  root->tau=0.0;
  root->left=0;
  root->right=255;
…

MagickAllocateMemory(...) may return NULL, so the following operations on the “root" will dereference null pointer to cause memory error.

Credit: ADLab of Venustech

[Bob Friesenhahn]

This problem is fixed by Mercurial changeset 15211:c550763898eb. Thanks for the report!