+struct isl_mat *isl_mat_extend(struct isl_ctx *ctx, struct isl_mat *mat,
+ unsigned n_row, unsigned n_col)
+{
+ int i;
+ isl_int *old;
+
+ if (!mat)
+ return NULL;
+
+ if (mat->n_col >= n_col && mat->n_row >= n_row)
+ return mat;
+
+ if (mat->n_col < n_col) {
+ struct isl_mat *new_mat;
+
+ new_mat = isl_mat_alloc(ctx, n_row, n_col);
+ if (!new_mat)
+ goto error;
+ for (i = 0; i < mat->n_row; ++i)
+ isl_seq_cpy(new_mat->row[i], mat->row[i], mat->n_col);
+ isl_mat_free(ctx, mat);
+ return new_mat;
+ }
+
+ mat = isl_mat_cow(ctx, mat);
+ if (!mat)
+ goto error;
+
+ assert(mat->ref == 1);
+ old = mat->block.data;
+ mat->block = isl_blk_extend(ctx, mat->block, n_row * mat->n_col);
+ if (isl_blk_is_error(mat->block))
+ goto error;
+ mat->row = isl_realloc_array(ctx, mat->row, isl_int *, n_row);
+ if (!mat->row)
+ goto error;
+
+ for (i = 0; i < mat->n_row; ++i)
+ mat->row[i] = mat->block.data + (mat->row[i] - old);
+ for (i = mat->n_row; i < n_row; ++i)
+ mat->row[i] = mat->block.data + i * mat->n_col;
+ mat->n_row = n_row;
+
+ return mat;
+error:
+ isl_mat_free(ctx, mat);
+ return NULL;
+}
+