universe@103: /*
universe@103:  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS HEADER.
olaf@13:  *
universe@259:  * Copyright 2017 Mike Becker, Olaf Wintermann All rights reserved.
universe@103:  *
universe@103:  * Redistribution and use in source and binary forms, with or without
universe@103:  * modification, are permitted provided that the following conditions are met:
universe@103:  *
universe@103:  *   1. Redistributions of source code must retain the above copyright
universe@103:  *      notice, this list of conditions and the following disclaimer.
universe@103:  *
universe@103:  *   2. Redistributions in binary form must reproduce the above copyright
universe@103:  *      notice, this list of conditions and the following disclaimer in the
universe@103:  *      documentation and/or other materials provided with the distribution.
universe@103:  *
universe@103:  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
universe@103:  * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
universe@103:  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
universe@103:  * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
universe@103:  * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
universe@103:  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
universe@103:  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
universe@103:  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
universe@103:  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
universe@103:  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
universe@103:  * POSSIBILITY OF SUCH DAMAGE.
olaf@13:  */
olaf@13: 
universe@135: /**
universe@182:  * @file stack.h
universe@135:  * 
universe@182:  * Default stack memory allocation implementation.
universe@135:  * 
universe@135:  * @author Mike Becker
universe@135:  * @author Olaf Wintermann
universe@135:  */
universe@135: 
universe@182: #ifndef UCX_STACK_H
universe@182: #define	UCX_STACK_H
olaf@13: 
universe@259: #include "ucx.h"
universe@259: #include "allocator.h"
universe@38: 
olaf@13: #ifdef	__cplusplus
olaf@13: extern "C" {
olaf@13: #endif
olaf@13: 
olaf@13: 
universe@135: /**
universe@182:  * UCX stack structure.
universe@135:  */
olaf@13: typedef struct {
universe@182:     /** UcxAllocator based on this stack */
universe@182:     UcxAllocator allocator;
olaf@158:     
universe@182:     /** Stack size. */
universe@182:     size_t size;
universe@146:     
universe@182:     /** Pointer to the bottom of the stack */
universe@182:     char *space;
universe@146:     
universe@182:     /** Pointer to the top of the stack */
universe@182:     char *top;
universe@182: } UcxStack;
universe@135: 
universe@135: /**
universe@185:  * Metadata for each UCX stack element.
universe@185:  */
universe@185: struct ucx_stack_metadata {
universe@185:     /**
universe@185:      * Location of the previous element (<code>NULL</code> if this is the first)
universe@185:      */
universe@185:     char *prev;
universe@185:     
universe@185:     /** Size of this element */
universe@185:     size_t size;
universe@185: };
universe@185: 
universe@185: /**
universe@185:  * Initializes UcxStack structure with memory.
universe@135:  * 
universe@185:  * @param stack a pointer to an uninitialized stack structure
universe@182:  * @param space the memory area that shall be managed
universe@182:  * @param size size of the memory area
universe@182:  * @return a new UcxStack structure
universe@135:  */
universe@185: void ucx_stack_init(UcxStack *stack, char* space, size_t size);
universe@135: 
universe@135: /**
universe@182:  * Allocates stack memory.
universe@135:  * 
universe@182:  * @param stack a pointer to the stack
universe@135:  * @param n amount of memory to allocate
universe@135:  * @return a pointer to the allocated memory
universe@135:  * @see ucx_allocator_malloc()
universe@135:  */
universe@182: void *ucx_stack_malloc(UcxStack *stack, size_t n);
universe@182: 
universe@135: /**
universe@182:  * Alias for #ucx_stack_malloc().
universe@182:  * @param stack a pointer to the stack
universe@182:  * @param n amount of memory to allocate
universe@182:  * @return a pointer to the allocated memory
universe@182:  * @see ucx_stack_malloc
universe@182:  */
universe@188: #define ucx_stack_push(stack, n) ucx_stack_malloc(stack, n)
universe@182: 
universe@182: /**
universe@182:  * Allocates an array of stack memory
universe@135:  * 
universe@182:  * The content of the allocated memory is set to zero.
universe@135:  * 
universe@182:  * @param stack a pointer to the stack
universe@135:  * @param nelem amount of elements to allocate
universe@135:  * @param elsize amount of memory per element
universe@135:  * @return a pointer to the allocated memory
universe@135:  * @see ucx_allocator_calloc()
universe@135:  */
universe@182: void *ucx_stack_calloc(UcxStack *stack, size_t nelem, size_t elsize);
universe@146: 
universe@135: /**
universe@182:  * Alias for #ucx_stack_calloc().
universe@135:  * 
universe@182:  * @param stack a pointer to the stack
universe@188:  * @param n amount of elements to allocate
universe@182:  * @param elsize amount of memory per element
universe@182:  * @return a pointer to the allocated memory
universe@182:  * @see ucx_stack_calloc
universe@182:  */
universe@188: #define ucx_stack_pusharr(stack,n,elsize) ucx_stack_calloc(stack,n,elssize)
universe@182: 
universe@182: /**
universe@182:  * Reallocates memory on the stack.
universe@141:  * 
universe@182:  * Shrinking memory is always safe. Extending memory can be very expensive. 
universe@182:  * 
universe@182:  * @param stack the stack
universe@135:  * @param ptr a pointer to the memory that shall be reallocated
universe@135:  * @param n the new size of the memory
universe@182:  * @return a pointer to the new location of the memory
universe@135:  * @see ucx_allocator_realloc()
universe@135:  */
universe@182: void *ucx_stack_realloc(UcxStack *stack, void *ptr, size_t n);
universe@146: 
universe@135: /**
universe@182:  * Frees memory on the stack.
universe@135:  * 
universe@182:  * Freeing stack memory behaves in a special way.
universe@135:  * 
universe@182:  * If the element, that should be freed, is the top most element of the stack,
universe@182:  * it is removed from the stack. Otherwise it is marked as freed. Marked
universe@182:  * elements are removed, when they become the top most elements of the stack.
universe@135:  * 
universe@182:  * @param stack a pointer to the stack
universe@135:  * @param ptr a pointer to the memory that shall be freed
universe@135:  */
universe@182: void ucx_stack_free(UcxStack *stack, void *ptr);
universe@182: 
olaf@13: 
universe@135: /**
universe@182:  * Returns the size of the top most element.
universe@182:  * @param stack a pointer to the stack
universe@182:  * @return the size of the top most element
universe@135:  */
universe@185: #define ucx_stack_topsize(stack) ((stack)->top ? ((struct ucx_stack_metadata*)\
universe@185:                                   (stack)->top - 1)->size : 0)
olaf@13: 
universe@135: /**
universe@182:  * Removes the top most element from the stack and copies the content to <code>
universe@182:  * dest</code>, if specified.
universe@135:  * 
universe@182:  * Use #ucx_stack_topsize()# to get the amount of memory that must be available
universe@182:  * at the location of <code>dest</code>.
universe@135:  * 
universe@182:  * @param stack a pointer to the stack
universe@182:  * @param dest the location where the contents shall be written to, or <code>
universe@182:  * NULL</code>, if the element shall only be removed.
universe@182:  * @see ucx_stack_free
universe@182:  * @see ucx_stack_popn
universe@135:  */
universe@217: #define ucx_stack_pop(stack, dest) ucx_stack_popn(stack, dest, (size_t)-1)
universe@135: 
universe@135: /**
universe@182:  * Removes the top most element from the stack and copies the content to <code>
universe@182:  * dest</code>.
universe@135:  * 
universe@182:  * In contrast to #ucx_stack_pop() the <code>dest</code> pointer <code>MUST
universe@182:  * NOT</code> be <code>NULL</code>.
universe@135:  * 
universe@182:  * @param stack a pointer to the stack
universe@182:  * @param dest the location where the contents shall be written to
universe@182:  * @param n copies at most n elements to <code>dest</code>
universe@182:  * @see ucx_stack_pop
universe@182:  */
universe@182: void ucx_stack_popn(UcxStack *stack, void *dest, size_t n);
universe@182: 
universe@182: /**
universe@182:  * Returns the remaining available memory on the specified stack.
universe@135:  * 
universe@182:  * @param stack a pointer to the stack
universe@182:  * @return the remaining available memory
universe@135:  */
universe@185: size_t ucx_stack_avail(UcxStack *stack);
universe@185: 
universe@185: /**
universe@185:  * Checks, if the stack is empty.
universe@185:  * 
universe@185:  * @param stack a pointer to the stack
universe@185:  * @return nonzero, if the stack is empty, zero otherwise
universe@185:  */
universe@185: #define ucx_stack_empty(stack) (!(stack)->top)
universe@185: 
universe@185: /**
universe@185:  * Computes a recommended size for the stack memory area. Note, that
universe@185:  * reallocations have not been taken into account, so you might need to reserve
universe@185:  * twice as much memory to allow many reallocations.
universe@185:  * 
universe@185:  * @param size the approximate payload
universe@185:  * @param elems the approximate count of element allocations
universe@185:  * @return a recommended size for the stack space based on the information
universe@185:  * provided
universe@185:  */
universe@185: #define ucx_stack_dim(size, elems) (size+sizeof(struct ucx_stack_metadata) * \
universe@185:                                     (elems + 1))
universe@182: 
olaf@13: 
olaf@13: #ifdef	__cplusplus
olaf@13: }
olaf@13: #endif
olaf@13: 
universe@182: #endif	/* UCX_STACK_H */
olaf@13: