1 /*
2 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS HEADER.
3 *
4 * Copyright 2017 Mike Becker, Olaf Wintermann All rights reserved.
5 *
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions are met:
8 *
9 * 1. Redistributions of source code must retain the above copyright
10 * notice, this list of conditions and the following disclaimer.
11 *
12 * 2. Redistributions in binary form must reproduce the above copyright
13 * notice, this list of conditions and the following disclaimer in the
14 * documentation and/or other materials provided with the distribution.
15 *
16 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
17 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
18 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
19 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
20 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
21 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
22 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
23 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
24 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
25 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
26 * POSSIBILITY OF SUCH DAMAGE.
27 */
28
29 #include "ucx/stack.h"
30
31 #include <string.h>
32
33 static size_t ucx_stack_align(size_t n) {
34 int align = n % sizeof(void*);
35 if (align) {
36 n += sizeof(void*) - align;
37 }
38 return n;
39 }
40
41 void ucx_stack_init(UcxStack *stack, char* space, size_t size) {
42 stack->size = size - size % sizeof(void*);
43 stack->space = space;
44 stack->top = NULL;
45
46 stack->allocator.pool = stack;
47 stack->allocator.malloc = (ucx_allocator_malloc) ucx_stack_malloc;
48 stack->allocator.calloc = (ucx_allocator_calloc) ucx_stack_calloc;
49 stack->allocator.realloc = (ucx_allocator_realloc) ucx_stack_realloc;
50 stack->allocator.free = (ucx_allocator_free) ucx_stack_free;
51 }
52
53 void *ucx_stack_malloc(UcxStack *stack, size_t n) {
54
55 if (ucx_stack_avail(stack) < ucx_stack_align(n)) {
56 return NULL;
57 } else {
58 char *prev = stack->top;
59 if (stack->top) {
60 stack->top += ucx_stack_align(ucx_stack_topsize(stack));
61 } else {
62 stack->top = stack->space;
63 }
64
65 ((struct ucx_stack_metadata*)stack->top)->prev = prev;
66 ((struct ucx_stack_metadata*)stack->top)->size = n;
67 stack->top += sizeof(struct ucx_stack_metadata);
68
69 return stack->top;
70 }
71 }
72
73 void *ucx_stack_calloc(UcxStack *stack, size_t nelem, size_t elsize) {
74 void *mem = ucx_stack_malloc(stack, nelem*elsize);
75 memset(mem, 0, nelem*elsize);
76 return mem;
77 }
78
79 void *ucx_stack_realloc(UcxStack *stack, void *ptr, size_t n) {
80 if (ptr == stack->top) {
81 if (stack->size - (stack->top - stack->space) < ucx_stack_align(n)) {
82 return NULL;
83 } else {
84 ((struct ucx_stack_metadata*)stack->top - 1)->size = n;
85 return ptr;
86 }
87 } else {
88 if (ucx_stack_align(((struct ucx_stack_metadata*)ptr - 1)->size) <
89 ucx_stack_align(n)) {
90 void *nptr = ucx_stack_malloc(stack, n);
91 if (nptr) {
92 memcpy(nptr, ptr, n);
93 ucx_stack_free(stack, ptr);
94
95 return nptr;
96 } else {
97 return NULL;
98 }
99 } else {
100 ((struct ucx_stack_metadata*)ptr - 1)->size = n;
101 return ptr;
102 }
103 }
104 }
105
106 void ucx_stack_free(UcxStack *stack, void *ptr) {
107 if (ptr == stack->top) {
108 stack->top = ((struct ucx_stack_metadata*) stack->top - 1)->prev;
109 } else {
110 struct ucx_stack_metadata *next = (struct ucx_stack_metadata*)(
111 (char*)ptr +
112 ucx_stack_align(((struct ucx_stack_metadata*) ptr - 1)->size)
113 );
114 next->prev = ((struct ucx_stack_metadata*) ptr - 1)->prev;
115 }
116 }
117
118 void ucx_stack_popn(UcxStack *stack, void *dest, size_t n) {
119 if (ucx_stack_empty(stack)) {
120 return;
121 }
122
123 if (dest) {
124 size_t len = ucx_stack_topsize(stack);
125 if (len > n) {
126 len = n;
127 }
128
129 memcpy(dest, stack->top, len);
130 }
131
132 ucx_stack_free(stack, stack->top);
133 }
134
135 size_t ucx_stack_avail(UcxStack *stack) {
136 size_t avail = ((stack->top ? (stack->size
137 - (stack->top - stack->space)
138 - ucx_stack_align(ucx_stack_topsize(stack)))
139 : stack->size));
140
141 if (avail > sizeof(struct ucx_stack_metadata)) {
142 return avail - sizeof(struct ucx_stack_metadata);
143 } else {
144 return 0;
145 }
146 }
147
148 void *ucx_stack_push(UcxStack *stack, size_t n, const void *data) {
149 void *space = ucx_stack_malloc(stack, n);
150 if (space) {
151 memcpy(space, data, n);
152 }
153 return space;
154 }
155
156 void *ucx_stack_pusharr(UcxStack *stack,
157 size_t nelem, size_t elsize, const void *data) {
158
159 // skip the memset by using malloc
160 void *space = ucx_stack_malloc(stack, nelem*elsize);
161 if (space) {
162 memcpy(space, data, nelem*elsize);
163 }
164 return space;
165 }
166