graph.h

   1 #ifndef GRAPH_H
   2 #define GRAPH_H
   3
   4 #include "stdbool.h"
   5 #include "buffer.h"
   6 #include "errors.h"
   7
   8 enum {
   9     EPINDIR = ERR_GROUP(7),     // incorrect pin directions
  10     EUNCONNECTED,               // there are unconnected pins
  11     ENO_AGREEABLE_FORMAT,       // no format that both nodes will agree on
  12 };
  13
  14 enum direction {
  15     DIR_IN,
  16     DIR_OUT,
  17 };
  18
  19 struct graphnode;
  20 struct graphpin;
  21 struct graphedge;
  22
  23 struct graphnode_functab {
  24     bool (* is_acceptable_input_format)(struct graphnode *node, struct graphpin *pin,
  25       const struct aformat *af);
  26     err_t (* get_output_format)(struct graphnode *node, struct graphpin *pin,
  27       struct aformat *af);
  28     err_t (* set_buffer)(struct graphnode *node, struct graphpin *pin, struct buffer *buf);
  29     err_t (* run)(struct graphnode *node);
  30 };
  31
  32 struct graphedge {
  33     struct graphpin *a, *b;
  34     struct buffer buf;
  35     bool processed;
  36 };
  37
  38 struct graphpin {
  39     struct graphpin *next;
  40     struct graphnode *node;
  41     struct graphedge *edge;
  42     const char *name;
  43     enum direction dir;
  44     int tag;                    // user-defined value
  45 };
  46
  47 struct graphnode {
  48     const struct graphnode_functab *functab;
  49     struct graphnode *prev, *next;          // nodes in a list (doesn't relate to data flow)
  50     struct graphnode *sorted_prev,
  51                      *sorted_next;  // nodes in topological order (the order to run them in)
  52     struct graphpin *pins;
  53     const char *name;               // name (for debugging, atm)
  54     void *extra;                    // pointer to additional data, if needed
  55     char extra_data[];
  56 };
  57
  58 struct graph {
  59     struct graphnode *node_first, *node_last,
  60                      *sorted_nodes;
  61 };
  62
  63 err_t graphnode_add_pin(struct graphnode *node, struct graphpin **pin_out); // create a new pin for the node
  64 void graphnode_remove_pin(struct graphnode *node, struct graphpin *pin);    // remove a pin from this node
  65
  66 err_t graphnode_create(struct graphnode **node_out, const struct graphnode_functab *functab, size_t extra_bytes);         // create new node (with extra_bytes additional space)
  67 void graphnode_free(struct graphnode *node);        // destroy a node
  68 bool graphnode_is_source(struct graphnode *node);   // returns true if node is a source (no inputs)
  69 bool graphnode_all_inputs_connected(struct graphnode *node);    // returns true if ... well, have a guess!
  70
  71 err_t graph_create(struct graph *graph);            // create a new graph
  72 void graph_destroy(struct graph *graph);            // destroy a graph and its contents
  73 err_t graph_add_node(struct graph *graph, struct graphnode *node);      // add a node to the graph (doesn't connect anything - just adds it)
  74 err_t graph_remove_node(struct graph *graph, struct graphnode *node);   // removes a node from the graph (doesn't destroy the node)
  75
  76 // Make connections. Pins a and b must be unconnected.
  77 // Pin a must be an output, pin b must be an input.
  78 err_t graph_connect(struct graph *graph, struct graphpin *a, struct graphpin *b);
  79
  80 err_t graph_sort(struct graph *graph);                // does a topological sort of graph nodes (must be called before running the graph, after the graph has changed)
  81 err_t graph_run(struct graph *graph);                 // run the graph! (actually does stuff)
  82
  83 #endif