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     ECANNOT_GUESS_FORMAT,       // cannot guess a node's output format
  13     EBAD_FORMAT,                // bad format
  14 };
  15
  16 enum direction {
  17     DIR_IN,
  18     DIR_OUT,
  19 };
  20
  21 struct graphnode;
  22 struct graphpin;
  23 struct graphedge;
  24
  25 struct graphnode_functab {
  26     bool (* is_acceptable_input_format)(struct graphnode *node, struct graphpin *pin, const struct aformat *af);
  27     err_t (* get_ideal_input_format)(struct graphnode *node, struct graphpin *pin, struct aformat *af);
  28     err_t (* get_output_format)(struct graphnode *node, struct graphpin *pin, struct aformat *af);
  29     err_t (* set_buffer)(struct graphnode *node, struct graphpin *pin, struct buffer *buf);
  30     err_t (* run)(struct graphnode *node);
  31 };
  32
  33 struct graphedge {
  34     struct graphpin *a, *b;
  35     struct buffer buf;
  36     bool processed;
  37 };
  38
  39 struct graphpin {
  40     struct graphpin *next;
  41     struct graphnode *node;
  42     struct graphedge *edge;
  43     const char *name;
  44     enum direction dir;
  45     int tag;                    // user-defined value
  46 };
  47
  48 struct graphnode {
  49     const struct graphnode_functab *functab;
  50     struct graphnode *prev, *next;          // nodes in a list (doesn't relate to data flow)
  51     struct graphnode *sorted_prev,
  52                      *sorted_next;  // nodes in topological order (the order to run them in)
  53     struct graphpin *pins;
  54     const char *name;               // name (for debugging, atm)
  55     void *extra;                    // pointer to additional data, if needed
  56     char extra_data[];
  57 };
  58
  59 struct graph {
  60     struct graphnode *node_first, *node_last,
  61                      *sorted_nodes;
  62 };
  63
  64 struct graphpin *graphnode_get_pin(struct graphnode *node, enum direction dir); // return the first pin of direction 'dir'
  65 err_t graphnode_add_pin(struct graphnode *node, struct graphpin **pin_out); // create a new pin for the node
  66 void graphnode_remove_pin(struct graphnode *node, struct graphpin *pin);    // remove a pin from this node
  67
  68 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)
  69 void graphnode_free(struct graphnode *node);        // destroy a node
  70 bool graphnode_is_source(struct graphnode *node);   // returns true if node is a source (no inputs)
  71 bool graphnode_all_inputs_connected(struct graphnode *node);    // returns true if ... well, have a guess!
  72
  73 err_t graph_create(struct graph *graph);            // create a new graph
  74 void graph_destroy(struct graph *graph);            // destroy a graph and its contents
  75 err_t graph_add_node(struct graph *graph, struct graphnode *node);      // add a node to the graph (doesn't connect anything - just adds it)
  76 err_t graph_remove_node(struct graph *graph, struct graphnode *node);   // removes a node from the graph (doesn't destroy the node)
  77
  78 // Make connections. Pins a and b must be unconnected.
  79 // Pin a must be an output, pin b must be an input.
  80 err_t graph_connect(struct graph *graph, struct graphpin *a, struct graphpin *b);
  81
  82 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)
  83 err_t graph_run(struct graph *graph);                 // run the graph! (actually does stuff)
  84
  85 #endif