Add stack

src/extra.c

@@ -81,6 +81,59 @@ char* libcdsb_strndup(const char* s, size_t n) {
 /*#####################################################################################################################*/
 
 
+void libcdsb_stack_init(stack_t* x) {
+    memset(x, 0, sizeof(*x));
+}
+
+
+void libcdsb_stack_push(stack_t* x, void* value) {
+    stack_t* n;
+
+    if (x->value) {
+        if (!(n = malloc(sizeof(*n))))
+            abort();
+
+        n->prev  = x->prev;
+        n->value = x->value;
+        x->prev  = n;
+    }
+
+    x->value = value;
+}
+
+void* libcdsb_stack_pop(stack_t* x) {
+
+    stack_t* n;
+    void*    v;
+
+    v = x->value;
+
+    if (x->prev) {
+        n = x->prev;
+        x->prev = n->prev;
+        x->value = n->value;
+        free(n);
+    } else x->value = 0;
+
+    return v;
+}
+
+
+void libcdsb_stack_flush(stack_t* stack) {
+    stack_t* c;
+
+    while (stack->prev) {
+        c = stack->prev;
+        stack->prev = c->prev;
+        free(c);
+    }
+
+    stack->value = 0;
+}
+
+/*#####################################################################################################################*/
+
+
 size_t libcdsb_strlen(const char* s) {
     static const size_t m = (sizeof(size_t) == 8) ? 0x8080808080808080UL : 0x80808080UL;
     static const size_t d = (sizeof(size_t) == 8) ? 0x0101010101010101UL : 0x01010101UL;