buffer_tree.c

   1 #include <regex.h>
   2 #include <stdbool.h>
   3
   4 #include "para.h"
   5 #include "list.h"
   6 #include "string.h"
   7 //#include "buffer_tree.h"
   8
   9
  10 struct btr_buffer {
  11         char *buf;
  12         size_t size;
  13         /** The number of references to this buffer. */
  14         int refcount;
  15 };
  16
  17 struct btr_buffer_reference {
  18         struct btr_buffer *btrb;
  19         size_t consumed;
  20         /* Each buffer reference belongs to the buffer queue list of some buffer tree node. */
  21         struct list_head node;
  22 };
  23
  24 struct btr_node {
  25         char *name;
  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;
  31         /**
  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.
  35          */
  36         struct list_head buffer_queue;
  37 };
  38
  39 #define FOR_EACH_TARGET_NODE(_tn, _btrn) list_for_each_entry((_tn), \
  40         &((_btrn)->children), node)
  41
  42 #define FOR_EACH_BUFFER_REF(_br, _btrn) \
  43         list_for_each_entry((_br), &(_btrn)->buffer_queue, node)
  44 #define FOR_EACH_BUFFER_REF_SAFE(_br, _tmp, _btrn) \
  45         list_for_each_entry_safe((_br), (_tmp), &(_btrn)->buffer_queue, node)
  46
  47 INIT_STDERR_LOGGING(0);
  48
  49 struct btr_node *btr_new_node(char *name, struct btr_node *parent)
  50 {
  51         struct btr_node *btrn = para_malloc(sizeof(*btrn));
  52
  53         btrn->name = para_strdup(name);
  54         btrn->parent = parent;
  55         if (parent)
  56                 list_add_tail(&btrn->node, &parent->children);
  57         INIT_LIST_HEAD(&btrn->children);
  58         INIT_LIST_HEAD(&btrn->buffer_queue);
  59         return btrn;
  60 }
  61
  62 static struct btr_buffer *new_btrb(char *buf, size_t size)
  63 {
  64         struct btr_buffer *btrb = para_malloc(sizeof(*btrb));
  65
  66         btrb->buf = buf;
  67         btrb->size = size;
  68         btrb->refcount = 0;
  69         return btrb;
  70 }
  71
  72 void btr_drop_buffer_reference(struct btr_buffer_reference *br)
  73 {
  74         struct btr_buffer *btrb = br->btrb;
  75
  76         list_del(&br->node);
  77         free(br);
  78         btrb->refcount--;
  79         if (btrb->refcount == 0) {
  80                 free(btrb->buf);
  81                 free(btrb);
  82         }
  83 }
  84
  85 static void add_btrb_to_targets(struct btr_buffer *btrb, struct btr_node *btrn)
  86 {
  87         struct btr_node *tn; /* target node */
  88
  89         FOR_EACH_TARGET_NODE(tn, btrn) {
  90                 struct btr_buffer_reference *br = para_malloc(sizeof(*br));
  91                 br->btrb = btrb;
  92                 br->consumed = 0;
  93                 list_add_tail(&br->node, &tn->buffer_queue);
  94                 btrb->refcount++;
  95         }
  96 }
  97
  98 void btr_add_output(char *buf, size_t size, struct btr_node *btrn)
  99 {
 100         struct btr_buffer *btrb;
 101
 102         btrb = new_btrb(buf, size);
 103         add_btrb_to_targets(btrb, btrn);
 104 }
 105
 106 void btr_pushdown_br(struct btr_buffer_reference *br, struct btr_node *btrn)
 107 {
 108         add_btrb_to_targets(br->btrb, btrn);
 109         btr_drop_buffer_reference(br);
 110 }
 111
 112 void btr_pushdown(struct btr_node *btrn)
 113 {
 114         struct btr_buffer_reference *br, *tmp;
 115
 116         FOR_EACH_BUFFER_REF_SAFE(br, tmp, btrn)
 117                 btr_pushdown_br(br, btrn);
 118 }
 119
 120 bool btr_no_children(struct btr_node *btrn)
 121 {
 122         return list_empty(&btrn->children);
 123 }
 124
 125 bool btr_no_parent(struct btr_node *btrn)
 126 {
 127         return !btrn->parent;
 128 }
 129
 130 bool btr_inplace_ok(struct btr_node *btrn)
 131 {
 132         if (!btrn->parent)
 133                 return true;
 134         return list_is_singular(&btrn->parent->children);
 135 }
 136
 137 struct btr_buffer_reference *btr_next_br(struct btr_node *btrn)
 138 {
 139         if (list_empty(&btrn->buffer_queue))
 140                 return NULL;
 141         return list_first_entry(&btrn->buffer_queue, struct btr_buffer_reference, node);
 142 }
 143
 144 static inline size_t br_available_bytes(struct btr_buffer_reference *br)
 145 {
 146         return br->btrb->size - br->consumed;
 147 }
 148
 149 size_t btr_get_buffer_by_reference(struct btr_buffer_reference *br, char **buf)
 150 {
 151         *buf = br->btrb->buf + br->consumed;
 152         return br_available_bytes(br);
 153 }
 154
 155 void btr_increase_used_bytes(struct btr_buffer_reference *br, size_t consumed)
 156 {
 157         br->consumed += consumed;
 158         if (br->consumed == br->btrb->size)
 159                 btr_drop_buffer_reference(br);
 160 }
 161
 162 static void flush_input_queue(struct btr_node *btrn)
 163 {
 164         struct btr_buffer_reference *br, *tmp;
 165         FOR_EACH_BUFFER_REF_SAFE(br, tmp, btrn)
 166                 btr_drop_buffer_reference(br);
 167 }
 168
 169 void btr_del_node(struct btr_node *btrn)
 170 {
 171         struct btr_node *tn;
 172
 173         FOR_EACH_TARGET_NODE(tn, btrn)
 174                 tn->parent = NULL;
 175         flush_input_queue(btrn);
 176         if (btrn->parent)
 177                 list_del(&btrn->node);
 178         free(btrn->name);
 179         free(btrn);
 180 }
 181
 182 size_t btr_get_input_queue_size(struct btr_node *btrn)
 183 {
 184         struct btr_buffer_reference *br;
 185         size_t size = 0;
 186
 187         FOR_EACH_BUFFER_REF(br, btrn)
 188                 size += br_available_bytes(br);
 189         return size;
 190 }
 191
 192 int main(void)
 193 {
 194         return 1;
 195 }