7 #include "buffer_tree.h"
13 /** The number of references to this buffer. */
17 struct btr_buffer_reference {
18 struct btr_buffer *btrb;
20 /* Each buffer reference belongs to the buffer queue list of some buffer tree node. */
21 struct list_head node;
26 struct btr_node *parent;
27 /* The position of this btr node in the buffer tree. */
28 struct list_head node;
29 /* The children nodes of this btr node are linked together in a list. */
30 struct list_head children;
32 * The input queue is a list of references to btr buffers. Each item on
33 * the list represents an input buffer which has not been completely
34 * used by this btr node.
36 struct list_head input_queue;
39 #define FOR_EACH_CHILD(_tn, _btrn) list_for_each_entry((_tn), \
40 &((_btrn)->children), node)
42 #define FOR_EACH_BUFFER_REF(_br, _btrn) \
43 list_for_each_entry((_br), &(_btrn)->input_queue, node)
44 #define FOR_EACH_BUFFER_REF_SAFE(_br, _tmp, _btrn) \
45 list_for_each_entry_safe((_br), (_tmp), &(_btrn)->input_queue, node)
47 struct btr_node *btr_new_node(char *name, struct btr_node *parent)
49 struct btr_node *btrn = para_malloc(sizeof(*btrn));
51 btrn->name = para_strdup(name);
52 btrn->parent = parent;
54 list_add_tail(&btrn->node, &parent->children);
55 INIT_LIST_HEAD(&btrn->children);
56 INIT_LIST_HEAD(&btrn->input_queue);
61 * Allocate a new btr buffer.
63 * The freshly allocated buffer will have a zero refcount.
65 static struct btr_buffer *new_btrb(char *buf, size_t size)
67 struct btr_buffer *btrb = para_malloc(sizeof(*btrb));
76 * Deallocate the reference, release the resources if refcount drops to zero.
78 static void btr_drop_buffer_reference(struct btr_buffer_reference *br)
80 struct btr_buffer *btrb = br->btrb;
85 if (btrb->refcount == 0) {
91 static void add_btrb_to_children(struct btr_buffer *btrb, struct btr_node *btrn)
95 FOR_EACH_CHILD(ch, btrn) {
96 struct btr_buffer_reference *br = para_malloc(sizeof(*br));
99 list_add_tail(&br->node, &ch->input_queue);
104 void btr_add_output(char *buf, size_t size, struct btr_node *btrn)
106 struct btr_buffer *btrb;
108 btrb = new_btrb(buf, size);
109 add_btrb_to_children(btrb, btrn);
112 static void btr_pushdown_br(struct btr_buffer_reference *br, struct btr_node *btrn)
114 add_btrb_to_children(br->btrb, btrn);
115 btr_drop_buffer_reference(br);
118 void btr_pushdown(struct btr_node *btrn)
120 struct btr_buffer_reference *br, *tmp;
122 FOR_EACH_BUFFER_REF_SAFE(br, tmp, btrn)
123 btr_pushdown_br(br, btrn);
126 /* Return true if this node has no children. */
127 bool btr_is_leaf_node(struct btr_node *btrn)
129 return list_empty(&btrn->children);
132 bool btr_no_parent(struct btr_node *btrn)
134 return !btrn->parent;
137 bool btr_inplace_ok(struct btr_node *btrn)
141 return list_is_singular(&btrn->parent->children);
144 struct btr_buffer_reference *btr_next_br(struct btr_node *btrn)
146 if (list_empty(&btrn->input_queue))
148 return list_first_entry(&btrn->input_queue, struct btr_buffer_reference, node);
152 static inline size_t br_available_bytes(struct btr_buffer_reference *br)
154 return br->btrb->size - br->consumed;
157 size_t btr_get_buffer_by_reference(struct btr_buffer_reference *br, char **buf)
159 *buf = br->btrb->buf + br->consumed;
160 return br_available_bytes(br);
163 void btr_increase_used_bytes(struct btr_buffer_reference *br, size_t consumed)
165 br->consumed += consumed;
166 if (br->consumed == br->btrb->size)
167 btr_drop_buffer_reference(br);
170 static void flush_input_queue(struct btr_node *btrn)
172 struct btr_buffer_reference *br, *tmp;
173 FOR_EACH_BUFFER_REF_SAFE(br, tmp, btrn)
174 btr_drop_buffer_reference(br);
177 void btr_del_node(struct btr_node *btrn)
181 FOR_EACH_CHILD(ch, btrn)
183 flush_input_queue(btrn);
185 list_del(&btrn->node);
190 size_t btr_get_input_queue_size(struct btr_node *btrn)
192 struct btr_buffer_reference *br;
195 FOR_EACH_BUFFER_REF(br, btrn)
196 size += br_available_bytes(br);