+/**
+ * Permute an 8x8 block.
+ * @param block the block which will be permuted according to the given permutation vector
+ * @param permutation the permutation vector
+ * @param last the last non zero coefficient in scantable order, used to speed the permutation up
+ * @param scantable the used scantable, this is only used to speed the permutation up, the block is not
+ * (inverse) permutated to scantable order!
+ */
+void ff_block_permute(int16_t *block, uint8_t *permutation, const uint8_t *scantable, int last)
+{
+ int i;
+ int16_t temp[64];
+
+ if(last<=0) return;
+ //if(permutation[1]==1) return; //FIXME it is ok but not clean and might fail for some permutations
+
+ for(i=0; i<=last; i++){
+ const int j= scantable[i];
+ temp[j]= block[j];
+ block[j]=0;
+ }
+
+ for(i=0; i<=last; i++){
+ const int j= scantable[i];
+ const int perm_j= permutation[j];
+ block[perm_j]= temp[j];
+ }
+}
+