+ assert (val_type_from_width (old_width) == val_type_from_width (new_width));
+
+ /* We need to call value_resize if either the new width is
+ longer than the old width (in which case the new characters
+ must be set to spaces) or if either width is a long string.
+ (We could omit resizing if both the old and new widths were
+ long and the new width was shorter, but we choose to do so
+ anyway in hopes of saving memory.) */
+ return (old_width != new_width
+ && (new_width > old_width
+ || old_width > MAX_SHORT_STRING
+ || new_width > MAX_SHORT_STRING));
+}
+
+/* Same as value_init, except that memory for VALUE (if
+ necessary) is allocated from POOL and will be freed
+ automatically when POOL is destroyed.
+
+ VALUE must not be freed manually by calling value_destroy. If
+ it needs to be resized, it must be done using
+ value_resize_pool instead of value_resize. */
+void
+value_init_pool (struct pool *pool, union value *value, int width)
+{
+ if (width > MAX_SHORT_STRING)
+ value->long_string = pool_alloc_unaligned (pool, width);
+}
+
+/* Same as value_resize, except that VALUE must have been
+ allocated from POOL using value_init_pool.
+
+ This function causes some memory in POOL to be wasted in some
+ cases (until the pool is freed), so it should only be done if
+ this is acceptable. */
+void
+value_resize_pool (struct pool *pool, union value *value,
+ int old_width, int new_width)
+{
+ assert (value_is_resizable (value, old_width, new_width));
+ if (new_width > old_width)
+ {
+ if (new_width > MAX_SHORT_STRING)
+ {
+ uint8_t *new_long_string = pool_alloc_unaligned (pool, new_width);
+ memcpy (new_long_string, value_str (value, old_width), old_width);
+ value->long_string = new_long_string;
+ }
+ memset (value_str_rw (value, new_width) + old_width, ' ',
+ new_width - old_width);
+ }