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fifo_lifo.c

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+/*
+ * fifo_lifo.c - simple FIFO/LIFO
+ *
+ * Copyright 2013 Edward V. Emelianoff <eddy@sao.ru>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
+ * MA 02110-1301, USA.
+ */
+#include <stdio.h>
+#include <stdlib.h>
+#include <err.h>
+
+#include "fifo_lifo.h"
+
+#ifndef Malloc
+#define Malloc my_alloc
+/**
+ * Memory allocation with control
+ * @param N - number of elements
+ * @param S - size of one element
+ * @return allocated memory or die
+ */
+void *my_alloc(size_t N, size_t S){
+    void *p = calloc(N, S);
+    if(!p) err(1, "malloc");
+    return p;
+}
+#endif
+#ifndef FREE
+#define FREE(arg) do{free(arg); arg = NULL;}while(0)
+#endif
+
+
+/**
+ * push data into the tail of a stack (like FIFO)
+ * @param lst (io) - list
+ * @param v (i)    - data to push
+ * @return pointer to just pused node
+ */
+List *push_tail(List **lst, Ldata v){
+	List *node;
+	if(!lst) return NULL;
+	if((node = (List*) Malloc(1, sizeof(List))) == 0)
+		return NULL; // allocation error
+	node->data = v; // insert data
+	if(!*lst){
+		*lst = node;
+		(*lst)->last = node;
+		return node;
+	}
+	(*lst)->last->next = node;
+	(*lst)->last = node;
+	return node;
+}
+
+/**
+ * push data into the head of a stack (like LIFO)
+ * @param lst (io) - list
+ * @param v (i)    - data to push
+ * @return pointer to just pused node
+ */
+List *push(List **lst, Ldata v){
+	List *node;
+	if(!lst) return NULL;
+	if((node = (List*) Malloc(1, sizeof(List))) == 0)
+		return NULL; // allocation error
+	node->data = v; // insert data
+	if(!*lst){
+		*lst = node;
+		(*lst)->last = node;
+		return node;
+	}
+	node->next = *lst;
+	node->last = (*lst)->last;
+	*lst = node;
+	return node;
+}
+
+/**
+ * get data from head of list
+ * @param lst (io) - list
+ * @return data from lst head
+ */
+Ldata pop(List **lst){
+	Ldata ret;
+	List *node = *lst;
+	if(!lst) errx(1, "NULL pointer to buffer");
+	if(!*lst) errx(1, "Empty buffer");
+	ret = (*lst)->data;
+	*lst = (*lst)->next;
+	FREE(node);
+	return ret;
+}
+
+#ifdef STANDALONE
+int main(void) {
+	List *f = NULL;
+	int i, d, ins[] = {4,2,6,1,3,4,7};
+	for(i = 0; i < 7; i++)
+		if(!(push(&f, ins[i])))
+			err(1, "Malloc error"); // can't insert
+	else printf("pushed %d\n", ins[i]);
+	while(f){
+		d = pop(&f);
+		printf("pulled: %d\n", d);
+	}
+	for(i = 0; i < 7; i++)
+		if(!(push_tail(&f, ins[i])))
+			err(1, "Malloc error"); // can't insert
+	else printf("pushed to head %d\n", ins[i]);
+	while(f){
+		d = pop(&f);
+		printf("pulled: %d\n", d);
+	}
+	return 0;
+}
+#endif