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comparison: ucx/stack.c

ucx/stack.c

changeset 124
80609f9675f1
child 152
62921b370c60
equal deleted inserted replaced
123:55adc92e7c09 124:80609f9675f1
1 /*
2 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS HEADER.
3 *
4 * Copyright 2015 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 "stack.h"
30 #include <string.h>
31
32 static size_t ucx_stack_align(size_t n) {
33 int align = n % sizeof(void*);
34 if (align) {
35 n += sizeof(void*) - align;
36 }
37 return n;
38 }
39
40 void ucx_stack_init(UcxStack *stack, char* space, size_t size) {
41 stack->size = size - size % sizeof(void*);
42 stack->space = space;
43 stack->top = NULL;
44
45 stack->allocator.pool = stack;
46 stack->allocator.malloc = (ucx_allocator_malloc) ucx_stack_malloc;
47 stack->allocator.calloc = (ucx_allocator_calloc) ucx_stack_calloc;
48 stack->allocator.realloc = (ucx_allocator_realloc) ucx_stack_realloc;
49 stack->allocator.free = (ucx_allocator_free) ucx_stack_free;
50 }
51
52 void *ucx_stack_malloc(UcxStack *stack, size_t n) {
53
54 if (ucx_stack_avail(stack) < ucx_stack_align(n)) {
55 return NULL;
56 } else {
57 char *prev = stack->top;
58 if (stack->top) {
59 stack->top += ucx_stack_align(ucx_stack_topsize(stack));
60 } else {
61 stack->top = stack->space;
62 }
63
64 ((struct ucx_stack_metadata*)stack->top)->prev = prev;
65 ((struct ucx_stack_metadata*)stack->top)->size = n;
66 stack->top += sizeof(struct ucx_stack_metadata);
67
68 return stack->top;
69 }
70 }
71
72 void *ucx_stack_calloc(UcxStack *stack, size_t nelem, size_t elsize) {
73 void *mem = ucx_stack_malloc(stack, nelem*elsize);
74 memset(mem, 0, nelem*elsize);
75 return mem;
76 }
77
78 void *ucx_stack_realloc(UcxStack *stack, void *ptr, size_t n) {
79 if (ptr == stack->top) {
80 if (stack->size - (stack->top - stack->space) < ucx_stack_align(n)) {
81 return NULL;
82 } else {
83 ((struct ucx_stack_metadata*)stack->top - 1)->size = n;
84 return ptr;
85 }
86 } else {
87 if (ucx_stack_align(((struct ucx_stack_metadata*)ptr - 1)->size) <
88 ucx_stack_align(n)) {
89 void *nptr = ucx_stack_malloc(stack, n);
90 if (nptr) {
91 memcpy(nptr, ptr, n);
92 ucx_stack_free(stack, ptr);
93
94 return nptr;
95 } else {
96 return NULL;
97 }
98 } else {
99 ((struct ucx_stack_metadata*)ptr - 1)->size = n;
100 return ptr;
101 }
102 }
103 }
104
105 void ucx_stack_free(UcxStack *stack, void *ptr) {
106 if (ptr == stack->top) {
107 stack->top = ((struct ucx_stack_metadata*) stack->top - 1)->prev;
108 } else {
109 struct ucx_stack_metadata *next = (struct ucx_stack_metadata*)(
110 (char*)ptr +
111 ucx_stack_align(((struct ucx_stack_metadata*) ptr - 1)->size)
112 );
113 next->prev = ((struct ucx_stack_metadata*) ptr - 1)->prev;
114 }
115 }
116
117 void ucx_stack_popn(UcxStack *stack, void *dest, size_t n) {
118 if (ucx_stack_empty(stack)) {
119 return;
120 }
121
122 size_t len = ucx_stack_topsize(stack);
123 if (len > n) {
124 len = n;
125 }
126
127 memcpy(dest, stack->top, len);
128
129 ucx_stack_free(stack, stack->top);
130 }
131
132 size_t ucx_stack_avail(UcxStack *stack) {
133 size_t avail = ((stack->top ? (stack->size
134 - (stack->top - stack->space)
135 - ucx_stack_align(ucx_stack_topsize(stack)))
136 : stack->size));
137
138 if (avail > sizeof(struct ucx_stack_metadata)) {
139 return avail - sizeof(struct ucx_stack_metadata);
140 } else {
141 return 0;
142 }
143 }

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