search_before, support for test2

added search_before()
added support for a temporary test file, test2.c  makefile etc.

.gitignore

 *.out
+tabify
\ No newline at end of file

Makefile

 run : main.out
 	./main.out
 
-.PHONY : run all test tabify
+.PHONY : run all test test2
 
 test.out : tabify llist.c llist.h test.c
 	gcc -ggdb -std=c99 -o test.out llist.c test.c
@@ -9,17 +9,24 @@ test.out : tabify llist.c llist.h test.c
 main.out : tabify llist.c llist.h main.c
 	gcc -std=c99 -o main.out llist.c main.c
 
+test2.out : tabify llist.c llist.h test2.c
+	gcc -std=c99 -o test2.out llist.c test2.c
+
 all : test.out main.out
 
 test : test.out
 	./test.out
 
+test2 : test2.out
+	./test2.out
+
 tabify : *.h *.c
 	for file in *.c *.h;\
 	do\
 	  unexpand -t4 --first-only $$file >temp ;\
 	  mv temp $$file;\
 	done
+	touch tabify
 
 gitindex : tabify *.c *.h
 	git add *.c *.h

llist.c

@@ -98,6 +98,37 @@ NODE_INT traverse(NODE *head, int pos){
 	return out;
 }
 
+NODE_INT search_before(NODE *head, datatype data, unsigned before){
+//return:
+// node non-null, num>-1: normal; found data at index num+before
+// node NULL, num 0 : head is NULL
+// node NULL, num<0 : completed before enough data processed. num is index.
+//                           e.g. search_before({1,2,3},2,3) -> (NULL, -2)
+// node non-null, num<0 : did not find data; returns node 'before' before last
+//                        if n is index of node returned, num is -(n+1) 
+	NODE_INT out;
+	out.node = NULL;
+	out.num = 0;
+	if(head==NULL)
+		return out;
+	if(before == 0)
+		return search(head,data);
+	before;
+	NODE **queue = calloc(before, sizeof(NODE*));
+	int i=0;
+	while(head != NULL && head->data != data){
+		queue[i] = head;
+		i = (i+1)%before;
+		out.num++;
+		head = head->next;
+	}
+	out.node = queue[i];
+	out.num -= before;
+	if(head == NULL)
+		out.num = (-1)-out.num;
+	return out;
+}
+
 int delete_node_after(NODE *head){
 //return:
 // 0 : normal

llist.h

@@ -17,6 +17,7 @@ void print_list(NODE *head);
 void print_node(NODE *head);
 NODE_INT psearch(NODE *head, datatype data);
 NODE_INT search(NODE *head, datatype data);
+NODE_INT search_before(NODE *head, datatype data, unsigned before);
 NODE *construct(datatype data, NODE *next);
 NODE_INT traverse(NODE *head, int pos);
 //NODE_INT traverse_before(NODE *head, int pos, int before);

test2.c

+#include <stdio.h>
+#include "llist.h"
+
+int main()
+{
+}
+
+//
+//	struct Node *start;
+//
+//	int arr[] = {10,20,30,40,50};
+//	start = construct_list(arr, 5);
+//	NODE_INT Return;
+//	Return = search_before(start, 60, 22);
+//	if(Return.node) printf("%d",Return.node->data);
+//	printf(" | %p , %d\n",Return.node,Return.num);
+//	return 0;
+//}