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comparison src/mem.c @ 29:e59c91d050c0

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*: add aligned malloc stuff :)
author Paper <paper@tflc.us>
date Thu, 24 Apr 2025 17:12:05 -0400
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28:c6c99ab1088a 29:e59c91d050c0
1 /**
2 * vec - a tiny SIMD vector library in C99
3 *
4 * Copyright (c) 2024 Paper
5 *
6 * Permission is hereby granted, free of charge, to any person obtaining a copy
7 * of this software and associated documentation files (the "Software"), to deal
8 * in the Software without restriction, including without limitation the rights
9 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
10 * copies of the Software, and to permit persons to whom the Software is
11 * furnished to do so, subject to the following conditions:
12 *
13 * The above copyright notice and this permission notice shall be included in all
14 * copies or substantial portions of the Software.
15 *
16 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
17 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
18 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
19 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
20 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
21 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
22 * SOFTWARE.
23 **/
24
25 #include "vec/mem.h"
26
27 #include <stdlib.h>
28 #include <string.h>
29
30 #define VEC_MALLOC_ALIGNMENT (64)
31
32 VEC_STATIC_ASSERT(!(VEC_MALLOC_ALIGNMENT & (VEC_MALLOC_ALIGNMENT - 1))
33 && (VEC_MALLOC_ALIGNMENT > 0),
34 "VEC_MALLOC_ALIGNMENT must be a power of two");
35
36 typedef unsigned char vec_alignment_type;
37
38 #define VEC_MALLOC_ADDITIONAL_SIZE (sizeof(vec_alignment_type) + (VEC_MALLOC_ALIGNMENT - 1))
39 #define VEC_MALLOC_MAX_SIZE (SIZE_MAX - VEC_MALLOC_ADDITIONAL_SIZE)
40
41 VEC_FUNC_IMPL void *vec_align_ptr(void *q)
42 {
43 vec_alignment_type diff;
44
45 diff = (((uintptr_t)q + (VEC_MALLOC_ALIGNMENT - 1)) & ~(VEC_MALLOC_ALIGNMENT - 1)) - (uintptr_t)q;
46 q = (char *)q + diff;
47
48 memcpy((char *)q - sizeof(diff), &diff, sizeof(diff));
49
50 return q;
51 }
52
53 /* reverses vec_align_ptr */
54 VEC_FUNC_IMPL void *vec_unalign_ptr(void *q)
55 {
56 vec_alignment_type diff;
57
58 memcpy(&diff, (char *)q - sizeof(diff), sizeof(diff));
59 q = (char *)q - diff;
60
61 return q;
62 }
63
64 void *vec_malloc(size_t size)
65 {
66 void *q;
67
68 if (size > VEC_MALLOC_MAX_SIZE)
69 return NULL;
70
71 /* allocate space for the diff (we have to do this,
72 * for realloc has no way of knowing the original ptr) */
73 q = malloc(size + VEC_MALLOC_ADDITIONAL_SIZE);
74 if (!q)
75 return NULL;
76
77 return vec_align_ptr(q);
78 }
79
80 void *vec_calloc(size_t count, size_t nmemb)
81 {
82 size_t size;
83 void *q;
84
85 size = count * nmemb;
86 if (size && size / count != nmemb)
87 return NULL; /* nope */
88
89 q = vec_malloc(size);
90
91 if (q)
92 memset(q, 0, size);
93
94 return q;
95 }
96
97 void *vec_realloc(void *ptr, size_t newsize)
98 {
99 vec_alignment_type diff;
100 void *q;
101
102 if (!ptr)
103 return vec_malloc(newsize);
104
105 if (newsize > VEC_MALLOC_MAX_SIZE)
106 return NULL;
107
108 q = realloc(vec_unalign_ptr(ptr), VEC_MALLOC_ADDITIONAL_SIZE);
109 if (!q)
110 return NULL;
111
112 return vec_align_ptr(q);
113 }
114
115 void vec_free(void *ptr)
116 {
117 if (ptr)
118 free(vec_unalign_ptr(ptr));
119 }