1 files changed, 37 insertions, 0 deletions
diff --git a/src/backend/backend.c b/src/backend/backend.c
new file mode 100644
index 0000000..122e84c
--- /dev/null
+++ b/src/backend/backend.c
@@ -0,0 +1,37 @@
+#ifndef BACKEND_C
+#define BACKEND_C BACKEND_C
+#include <backend.h>
+
+/*returns an array of pointers to state_and_transition structs*/
+struct State_And_Transitions** extract_transition_table(struct AST_States *states,struct AST_Transitions *transitions)
+{
+	struct State_And_Transitions **ret;
+	struct Queue *qs;
+	size_t i;
+
+	ret=malloc(sizeof(struct State_And_Transitions)*states->number_of_states);
+
+	/*calloc also initialises the queues
+	 *i-th queue is for transitions starting from the i-th state
+	 * */
+	qs=calloc(sizeof(struct Queue),states->number_of_states);
+
+	/*traverse transitions and push them into the queue of their coresponding state*/
+	for(i=0;i<transitions->size;++i)
+		Queue_Push(qs+transitions->transitions[i]->from->number,transitions->transitions[i]);
+
+	/*condense the queues into the arrays*/
+	for(i=0;i<states->number_of_states;++i)
+	{
+		ret[i]=malloc(sizeof(struct State_And_Transitions)+sizeof(struct AST_Transitions *[qs[i].size]));
+		ret[i]->state=states->states[i];
+		ret[i]->number_of_transitions=qs[i].size;
+		pointer_array_fill((void**)ret[i]->transitions,qs+i);
+	}
+
+	free(qs);
+
+	return ret;
+}
+
+#endif