diff -r 62f1a55535e7 -r 0b33b9396851 ucx/ucx/stack.h
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/ucx/ucx/stack.h	Mon Feb 04 17:49:50 2019 +0100
@@ -0,0 +1,240 @@
+/*
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS HEADER.
+ *
+ * Copyright 2017 Mike Becker, Olaf Wintermann All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ *   1. Redistributions of source code must retain the above copyright
+ *      notice, this list of conditions and the following disclaimer.
+ *
+ *   2. Redistributions in binary form must reproduce the above copyright
+ *      notice, this list of conditions and the following disclaimer in the
+ *      documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
+ * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ */
+
+/**
+ * @file stack.h
+ * 
+ * Default stack memory allocation implementation.
+ * 
+ * @author Mike Becker
+ * @author Olaf Wintermann
+ */
+
+#ifndef UCX_STACK_H
+#define	UCX_STACK_H
+
+#include "ucx.h"
+#include "allocator.h"
+
+#ifdef	__cplusplus
+extern "C" {
+#endif
+
+
+/**
+ * UCX stack structure.
+ */
+typedef struct {
+    /** UcxAllocator based on this stack */
+    UcxAllocator allocator;
+    
+    /** Stack size. */
+    size_t size;
+    
+    /** Pointer to the bottom of the stack */
+    char *space;
+    
+    /** Pointer to the top of the stack */
+    char *top;
+} UcxStack;
+
+/**
+ * Metadata for each UCX stack element.
+ */
+struct ucx_stack_metadata {
+    /**
+     * Location of the previous element (<code>NULL</code> if this is the first)
+     */
+    char *prev;
+    
+    /** Size of this element */
+    size_t size;
+};
+
+/**
+ * Initializes UcxStack structure with memory.
+ * 
+ * @param stack a pointer to an uninitialized stack structure
+ * @param space the memory area that shall be managed
+ * @param size size of the memory area
+ * @return a new UcxStack structure
+ */
+void ucx_stack_init(UcxStack *stack, char* space, size_t size);
+
+/**
+ * Allocates stack memory.
+ * 
+ * @param stack a pointer to the stack
+ * @param n amount of memory to allocate
+ * @return a pointer to the allocated memory or <code>NULL</code> on stack
+ * overflow
+ * @see ucx_allocator_malloc()
+ */
+void *ucx_stack_malloc(UcxStack *stack, size_t n);
+
+/**
+ * Allocates memory with #ucx_stack_malloc() and copies the specified data if
+ * the allocation was successful.
+ * 
+ * @param stack a pointer to the stack
+ * @param n amount of memory to allocate
+ * @param data a pointer to the data to copy
+ * @return a pointer to the allocated memory
+ * @see ucx_stack_malloc
+ */
+void *ucx_stack_push(UcxStack *stack, size_t n, const void *data);
+
+/**
+ * Allocates an array of stack memory
+ * 
+ * The content of the allocated memory is set to zero.
+ * 
+ * @param stack a pointer to the stack
+ * @param nelem amount of elements to allocate
+ * @param elsize amount of memory per element
+ * @return a pointer to the allocated memory
+ * @see ucx_allocator_calloc()
+ */
+void *ucx_stack_calloc(UcxStack *stack, size_t nelem, size_t elsize);
+
+/**
+ * Allocates memory with #ucx_stack_calloc() and copies the specified data if
+ * the allocation was successful.
+ * 
+ * @param stack a pointer to the stack
+ * @param nelem amount of elements to allocate
+ * @param elsize amount of memory per element
+ * @param data a pointer to the data
+ * @return a pointer to the allocated memory
+ * @see ucx_stack_calloc
+ */
+void *ucx_stack_pusharr(UcxStack *stack,
+        size_t nelem, size_t elsize, const void *data);
+
+/**
+ * Reallocates memory on the stack.
+ * 
+ * Shrinking memory is always safe. Extending memory can be very expensive. 
+ * 
+ * @param stack the stack
+ * @param ptr a pointer to the memory that shall be reallocated
+ * @param n the new size of the memory
+ * @return a pointer to the new location of the memory
+ * @see ucx_allocator_realloc()
+ */
+void *ucx_stack_realloc(UcxStack *stack, void *ptr, size_t n);
+
+/**
+ * Frees memory on the stack.
+ * 
+ * Freeing stack memory behaves in a special way.
+ * 
+ * If the element, that should be freed, is the top most element of the stack,
+ * it is removed from the stack. Otherwise it is marked as freed. Marked
+ * elements are removed, when they become the top most elements of the stack.
+ * 
+ * @param stack a pointer to the stack
+ * @param ptr a pointer to the memory that shall be freed
+ */
+void ucx_stack_free(UcxStack *stack, void *ptr);
+
+
+/**
+ * Returns the size of the top most element.
+ * @param stack a pointer to the stack
+ * @return the size of the top most element
+ */
+#define ucx_stack_topsize(stack) ((stack)->top ? ((struct ucx_stack_metadata*)\
+                                  (stack)->top - 1)->size : 0)
+
+/**
+ * Removes the top most element from the stack and copies the content to <code>
+ * dest</code>, if specified.
+ * 
+ * Use #ucx_stack_topsize()# to get the amount of memory that must be available
+ * at the location of <code>dest</code>.
+ * 
+ * @param stack a pointer to the stack
+ * @param dest the location where the contents shall be written to, or <code>
+ * NULL</code>, if the element shall only be removed.
+ * @see ucx_stack_free
+ * @see ucx_stack_popn
+ */
+#define ucx_stack_pop(stack, dest) ucx_stack_popn(stack, dest, (size_t)-1)
+
+/**
+ * Removes the top most element from the stack and copies the content to <code>
+ * dest</code>.
+ * 
+ * This function copies at most <code>n</code> bytes to the destination, but
+ * the element is always freed as a whole.
+ * If the element was larger than <code>n</code>, the remaining data is lost.
+ * 
+ * @param stack a pointer to the stack
+ * @param dest the location where the contents shall be written to
+ * @param n copies at most n bytes to <code>dest</code>
+ * @see ucx_stack_pop
+ */
+void ucx_stack_popn(UcxStack *stack, void *dest, size_t n);
+
+/**
+ * Returns the remaining available memory on the specified stack.
+ * 
+ * @param stack a pointer to the stack
+ * @return the remaining available memory
+ */
+size_t ucx_stack_avail(UcxStack *stack);
+
+/**
+ * Checks, if the stack is empty.
+ * 
+ * @param stack a pointer to the stack
+ * @return nonzero, if the stack is empty, zero otherwise
+ */
+#define ucx_stack_empty(stack) (!(stack)->top)
+
+/**
+ * Computes a recommended size for the stack memory area. Note, that
+ * reallocations have not been taken into account, so you might need to reserve
+ * twice as much memory to allow many reallocations.
+ * 
+ * @param size the approximate payload
+ * @param elems the approximate count of element allocations
+ * @return a recommended size for the stack space based on the information
+ * provided
+ */
+#define ucx_stack_dim(size, elems) (size+sizeof(struct ucx_stack_metadata) * \
+                                    (elems + 1))
+
+
+#ifdef	__cplusplus
+}
+#endif
+
+#endif	/* UCX_STACK_H */
+