From 8a813e877adea6c8e12a0845449fd45ff39f2574 Mon Sep 17 00:00:00 2001
From: Gregory Lirent <opensource@lirent.ru>
Date: Tue, 7 Jun 2022 21:35:13 +0300
Subject: [PATCH] Add stack

---
 include/extra/memory.h | 15 ++++++++++++
 src/extra.c            | 53 ++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 68 insertions(+)

diff --git a/include/extra/memory.h b/include/extra/memory.h
index d0a584d..fb3ca3a 100644
--- a/include/extra/memory.h
+++ b/include/extra/memory.h
@@ -7,6 +7,16 @@
 #ifndef LIBCDSB_EXTRA_MEMORY_H
 #define LIBCDSB_EXTRA_MEMORY_H
 
+typedef struct libcdsb_stack_node {
+    struct libcdsb_stack_node* prev;
+    void* value;
+} stack_t;
+
+extern void  libcdsb_stack_init (stack_t* stack);
+extern void  libcdsb_stack_push (stack_t* stack, void* value);
+extern void* libcdsb_stack_pop  (stack_t* stack);
+extern void  libcdsb_stack_flush(stack_t* stack);
+
 extern void* libcdsb_aalloc (size_t a, size_t n) LIBCDSB_nt__ LIBCDSB_wur__;
 extern void* libcdsb_malloc (size_t n)           LIBCDSB_nt__ LIBCDSB_wur__;
 extern void* libcdsb_calloc (size_t n, size_t c) LIBCDSB_nt__ LIBCDSB_wur__;
@@ -17,4 +27,9 @@ extern void* libcdsb_realloc(void  *p, size_t n) LIBCDSB_nt__ LIBCDSB_wur__;
 #define calloc        libcdsb_calloc
 #define realloc       libcdsb_realloc
 
+#define stack_init  libcdsb_stack_init
+#define stack_push  libcdsb_stack_push
+#define stack_pop   libcdsb_stack_pop
+#define stack_flush libcdsb_stack_flush
+
 #endif /* LIBCDSB_EXTRA_MEMORY_H */
diff --git a/src/extra.c b/src/extra.c
index 4d8ae6a..a1c261c 100644
--- a/src/extra.c
+++ b/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;