summaryrefslogtreecommitdiff
path: root/cache.c
blob: c9f0845e90936a01dfe2090c7a8782a7eb3c4dfc (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
/* -*- Mode: C; tab-width: 4; c-basic-offset: 4; indent-tabs-mode: nil -*- */
#include <stdlib.h>
#include <string.h>
#include <inttypes.h>
#include <assert.h>

#ifndef NDEBUG
#include <signal.h>
#endif

#include "cache.h"

#ifndef NDEBUG
const uint64_t redzone_pattern = 0xdeadbeefcafedeed;
int cache_error = 0;
#endif

cache_t* cache_create(const char *name, size_t bufsize, size_t align) {
    cache_t* ret = calloc(1, sizeof(cache_t));
    char* nm = strdup(name);
    if (ret == NULL || nm == NULL ||
        pthread_mutex_init(&ret->mutex, NULL) == -1) {
        free(ret);
        free(nm);
        return NULL;
    }

    ret->name = nm;
    STAILQ_INIT(&ret->head);

#ifndef NDEBUG
    ret->bufsize = bufsize + 2 * sizeof(redzone_pattern);
#else
    ret->bufsize = bufsize;
#endif
    assert(ret->bufsize >= sizeof(struct cache_free_s));

    return ret;
}

void cache_set_limit(cache_t *cache, int limit) {
    pthread_mutex_lock(&cache->mutex);
    cache->limit = limit;
    pthread_mutex_unlock(&cache->mutex);
}

static inline void* get_object(void *ptr) {
#ifndef NDEBUG
    uint64_t *pre = ptr;
    return pre + 1;
#else
    return ptr;
#endif
}

void cache_destroy(cache_t *cache) {
    while (!STAILQ_EMPTY(&cache->head)) {
        struct cache_free_s *o = STAILQ_FIRST(&cache->head);
        STAILQ_REMOVE_HEAD(&cache->head, c_next);
        free(o);
    }
    free(cache->name);
    pthread_mutex_destroy(&cache->mutex);
    free(cache);
}

void* cache_alloc(cache_t *cache) {
    void *ret;
    pthread_mutex_lock(&cache->mutex);
    ret = do_cache_alloc(cache);
    pthread_mutex_unlock(&cache->mutex);
    return ret;
}

void* do_cache_alloc(cache_t *cache) {
    void *ret;
    void *object;
    if (cache->freecurr > 0) {
        ret = STAILQ_FIRST(&cache->head);
        STAILQ_REMOVE_HEAD(&cache->head, c_next);
        object = get_object(ret);
        cache->freecurr--;
    } else if (cache->limit == 0 || cache->total < cache->limit) {
        object = ret = malloc(cache->bufsize);
        if (ret != NULL) {
            object = get_object(ret);

            cache->total++;
        }
    } else {
        object = NULL;
    }

#ifndef NDEBUG
    if (object != NULL) {
        /* add a simple form of buffer-check */
        uint64_t *pre = ret;
        *pre = redzone_pattern;
        ret = pre+1;
        memcpy(((char*)ret) + cache->bufsize - (2 * sizeof(redzone_pattern)),
               &redzone_pattern, sizeof(redzone_pattern));
    }
#endif

    return object;
}

void cache_free(cache_t *cache, void *ptr) {
    pthread_mutex_lock(&cache->mutex);
    do_cache_free(cache, ptr);
    pthread_mutex_unlock(&cache->mutex);
}

void do_cache_free(cache_t *cache, void *ptr) {
#ifndef NDEBUG
    /* validate redzone... */
    if (memcmp(((char*)ptr) + cache->bufsize - (2 * sizeof(redzone_pattern)),
               &redzone_pattern, sizeof(redzone_pattern)) != 0) {
        raise(SIGABRT);
        cache_error = 1;
        return;
    }
    uint64_t *pre = ptr;
    --pre;
    if (*pre != redzone_pattern) {
        raise(SIGABRT);
        cache_error = -1;
        return;
    }
    ptr = pre;
#endif
    if (cache->limit != 0 && cache->limit < cache->total) {
        free(ptr);
        cache->total--;
    } else {
        STAILQ_INSERT_HEAD(&cache->head, (struct cache_free_s *)ptr, c_next);
        cache->freecurr++;
    }
}