/*
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS HEADER.
*
* Copyright 2016 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.
*/
#include "stack.h"
#include <string.h>
static size_t ucx_stack_align(size_t n) {
int align = n % sizeof(void*);
if (align) {
n += sizeof(void*) - align;
}
return n;
}
void ucx_stack_init(UcxStack *stack, char* space, size_t size) {
stack->size = size - size % sizeof(void*);
stack->space = space;
stack->top = NULL;
stack->allocator.pool = stack;
stack->allocator.malloc = (ucx_allocator_malloc) ucx_stack_malloc;
stack->allocator.calloc = (ucx_allocator_calloc) ucx_stack_calloc;
stack->allocator.realloc = (ucx_allocator_realloc) ucx_stack_realloc;
stack->allocator.free = (ucx_allocator_free) ucx_stack_free;
}
void *ucx_stack_malloc(UcxStack *stack, size_t n) {
if (ucx_stack_avail(stack) < ucx_stack_align(n)) {
return NULL;
} else {
char *prev = stack->top;
if (stack->top) {
stack->top += ucx_stack_align(ucx_stack_topsize(stack));
} else {
stack->top = stack->space;
}
((struct ucx_stack_metadata*)stack->top)->prev = prev;
((struct ucx_stack_metadata*)stack->top)->size = n;
stack->top += sizeof(struct ucx_stack_metadata);
return stack->top;
}
}
void *ucx_stack_calloc(UcxStack *stack, size_t nelem, size_t elsize) {
void *mem = ucx_stack_malloc(stack, nelem*elsize);
memset(mem, 0, nelem*elsize);
return mem;
}
void *ucx_stack_realloc(UcxStack *stack, void *ptr, size_t n) {
if (ptr == stack->top) {
if (stack->size - (stack->top - stack->space) < ucx_stack_align(n)) {
return NULL;
} else {
((struct ucx_stack_metadata*)stack->top - 1)->size = n;
return ptr;
}
} else {
if (ucx_stack_align(((struct ucx_stack_metadata*)ptr - 1)->size) <
ucx_stack_align(n)) {
void *nptr = ucx_stack_malloc(stack, n);
if (nptr) {
memcpy(nptr, ptr, n);
ucx_stack_free(stack, ptr);
return nptr;
} else {
return NULL;
}
} else {
((struct ucx_stack_metadata*)ptr - 1)->size = n;
return ptr;
}
}
}
void ucx_stack_free(UcxStack *stack, void *ptr) {
if (ptr == stack->top) {
stack->top = ((struct ucx_stack_metadata*) stack->top - 1)->prev;
} else {
struct ucx_stack_metadata *next = (struct ucx_stack_metadata*)(
(char*)ptr +
ucx_stack_align(((struct ucx_stack_metadata*) ptr - 1)->size)
);
next->prev = ((struct ucx_stack_metadata*) ptr - 1)->prev;
}
}
void ucx_stack_popn(UcxStack *stack, void *dest, size_t n) {
if (ucx_stack_empty(stack)) {
return;
}
size_t len = ucx_stack_topsize(stack);
if (len > n) {
len = n;
}
memcpy(dest, stack->top, len);
ucx_stack_free(stack, stack->top);
}
size_t ucx_stack_avail(UcxStack *stack) {
size_t avail = ((stack->top ? (stack->size
- (stack->top - stack->space)
- ucx_stack_align(ucx_stack_topsize(stack)))
: stack->size));
if (avail > sizeof(struct ucx_stack_metadata)) {
return avail - sizeof(struct ucx_stack_metadata);
} else {
return 0;
}
}