+ if (ptr == NULL) {
+ return opj_aligned_alloc_n(alignment, new_size);
+ }
+ alignment--;
+ {
+ void *oldmem;
+ OPJ_UINT8 *newmem;
+ size_t overhead = alignment + sizeof(void *);
+
+ /* let's be extra careful */
+ assert(alignment <= (SIZE_MAX - sizeof(void *)));
+
+ /* Avoid integer overflow */
+ if (new_size > SIZE_MAX - overhead) {
+ return NULL;
+ }
+
+ oldmem = ((void**) ptr)[-1];
+ newmem = (OPJ_UINT8*)realloc(oldmem, new_size + overhead);
+ if (newmem == NULL) {
+ return newmem;
+ }
+
+ if (newmem == oldmem) {
+ r_ptr = ptr;
+ } else {
+ size_t old_offset;
+ size_t new_offset;
+
+ /* realloc created a new copy, realign the copied memory block */
+ old_offset = (size_t)((OPJ_UINT8*)ptr - (OPJ_UINT8*)oldmem);
+
+ /* offset = ((alignment + 1U) - ((size_t)(mem + sizeof(void*)) & alignment)) & alignment; */
+ /* Use the fact that alignment + 1U is a power of 2 */
+ new_offset = ((alignment ^ ((size_t)(newmem + sizeof(void*)) & alignment)) +
+ 1U) & alignment;
+ new_offset += sizeof(void*);
+ r_ptr = (void *)(newmem + new_offset);
+
+ if (new_offset != old_offset) {
+ memmove(newmem + new_offset, newmem + old_offset, new_size);
+ }
+ ((void**) r_ptr)[-1] = newmem;
+ }
+ }