libr/util: implement a simple stack

libr/util/t/stack: add test

libr/include/r_util.h

@@ -211,6 +211,13 @@ typedef struct r_list_range_t {
 	//RListComparator c;
 } RListRange;
 
+/* stack api */
+typedef struct r_stack_t {
+	void **elems;
+	unsigned int n_elems;
+	int top;
+} RStack;
+
 /* graph api */
 typedef struct r_graph_node_t {
 	RList *parents; // <RGraphNode>
@@ -232,6 +239,12 @@ typedef struct r_graph_t {
 } RGraph;
 
 #ifdef R_API
+R_API RStack *r_stack_new (unsigned int n);
+R_API void r_stack_free (RStack *s);
+R_API int r_stack_push (RStack *s, void *el);
+R_API void *r_stack_pop (RStack *s);
+R_API int r_stack_is_empty (RStack *s);
+
 R_API RGraphNode *r_graph_node_new (ut64 addr, void *data);
 R_API void r_graph_node_free (RGraphNode *n);
 R_API void r_graph_traverse(RGraph *t);

libr/util/Makefile

@@ -11,7 +11,7 @@ OBJS+=sandbox.o calc.o thread.o thread_lock.o thread_msg.o
 OBJS+=strpool.o bitmap.o strht.o p_date.o p_format.o print.o
 OBJS+=p_seven.o slist.o randomart.o log.o zip.o debruijn.o
 OBJS+=utf8.o strbuf.o lib.o name.o
-OBJS+=diff.o bdiff.o
+OBJS+=diff.o bdiff.o stack.o
 
 # DO NOT BUILD r_big api (not yet used and its buggy)
 ifeq (1,0)

libr/util/stack.c

@@ -0,0 +1,47 @@
+/* radare - LGPL - Copyright 2007-2015 - ret2libc */
+
+#include <r_util.h>
+
+R_API RStack *r_stack_new (unsigned int n) {
+	RStack *s = R_NEW0 (RStack);
+	s->elems = calloc(n, sizeof(void *));
+	if (!s->elems)
+		return NULL;
+
+	s->n_elems = n;
+	s->top = -1;
+	return s;
+}
+
+R_API void r_stack_free (RStack *s) {
+	free (s->elems);
+	free (s);
+}
+
+R_API int r_stack_push (RStack *s, void *el) {
+	if (s->top == s->n_elems - 1) {
+		/* reallocate the stack */
+		s->n_elems *= 2;
+		s->elems = realloc (s->elems, s->n_elems * sizeof(void *));
+		if (!s->elems)
+			return R_FALSE;
+	}
+
+	s->top++;
+	s->elems[s->top] = el;
+	return R_TRUE;
+}
+
+R_API void *r_stack_pop (RStack *s) {
+	void *res;
+	if (s->top == -1)
+		return NULL;
+
+	res = s->elems[s->top];
+	s->top--;
+	return res;
+}
+
+R_API int r_stack_is_empty (RStack *s) {
+	return s->top == -1;
+}

libr/util/t/Makefile

@@ -16,11 +16,12 @@ BINS+=test_sys
 BINS+=test_str
 BINS+=test_file_slurp_hexpairs
 BINS+=test_cmd_str
+BINS+=test_stack
 
 all: ${BINS}
 
 ${BINS}: $(addsuffix .o,$(BINS))
-	$(CC) $(LDFLAGS) -o $@ $< 
+	$(CC) $(LDFLAGS) -o $@ $@.o
 
 myclean:
 	rm -f ${BINS} *.o

libr/util/t/test_stack.c

@@ -0,0 +1,68 @@
+#include <r_util.h>
+
+void check (int n, int exp) {
+	if (n == exp) {
+		printf("[+] test passed (actual: %d; expected: %d)\n", n, exp);
+	} else {
+		printf("[-] test failed (actual: %d; expected: %d)\n", n, exp);
+	}
+}
+
+void check_empty(RStack *s, int exp) {
+	if (r_stack_is_empty(s) == exp) {
+		printf("[+] test passed (stack empty status)\n");
+	} else {
+		printf("[-] test failed (stack empty status)\n");
+	}
+}
+
+int main(int argc, char **argv) {
+	RStack *s = r_stack_new(5);
+	int n;
+
+	r_stack_push(s, (void *)10);
+	r_stack_push(s, (void *)1);
+	r_stack_push(s, (void *)2);
+	r_stack_push(s, (void *)3);
+	r_stack_push(s, (void *)4);
+	r_stack_push(s, (void *)5);
+	r_stack_push(s, (void *)6);
+	r_stack_push(s, (void *)8);
+	r_stack_push(s, (void *)9);
+	r_stack_push(s, (void *)6);
+	n = (int)r_stack_pop(s);
+	check(n, 6);
+	n = (int)r_stack_pop(s);
+	check(n, 9);
+	n = (int)r_stack_pop(s);
+	check(n, 8);
+	n = (int)r_stack_pop(s);
+	check(n, 6);
+	n = (int)r_stack_pop(s);
+	check(n, 5);
+	n = (int)r_stack_pop(s);
+	check(n, 4);
+	n = (int)r_stack_pop(s);
+	check(n, 3);
+	n = (int)r_stack_pop(s);
+	check(n, 2);
+	n = (int)r_stack_pop(s);
+	check(n, 1);
+	check_empty(s, R_FALSE);
+	n = (int)r_stack_pop(s);
+	check(n, 10);
+
+	check_empty(s, R_TRUE);
+	n = (int)r_stack_pop(s);
+	check(n, 0);
+	n = (int)r_stack_pop(s);
+	check(n, 0);
+	check_empty(s, R_TRUE);
+
+	r_stack_push(s, (void *)10);
+	r_stack_push(s, (void *)1);
+	check_empty(s, R_FALSE);
+
+	r_stack_free(s);
+	return 0;
+}