1/*
2 * Copyright (C) 2012 The Android Open Source Project
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 *      http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17#include <stdlib.h>
18#include <cutils/qsort_r_compat.h>
19
20#if HAVE_BSD_QSORT_R
21
22/*
23 * BSD qsort_r parameter order is as we have defined here.
24 */
25
26void qsort_r_compat(void* base, size_t nel, size_t width, void* thunk,
27        int (*compar)(void*, const void* , const void*)) {
28    qsort_r(base, nel, width, thunk, compar);
29}
30
31#elif HAVE_GNU_QSORT_R
32
33/*
34 * GNU qsort_r parameter order places the thunk parameter last.
35 */
36
37struct compar_data {
38    void* thunk;
39    int (*compar)(void*, const void* , const void*);
40};
41
42static int compar_wrapper(const void* a, const void* b, void* data) {
43    struct compar_data* compar_data = (struct compar_data*)data;
44    return compar_data->compar(compar_data->thunk, a, b);
45}
46
47void qsort_r_compat(void* base, size_t nel, size_t width, void* thunk,
48        int (*compar)(void*, const void* , const void*)) {
49    struct compar_data compar_data;
50    compar_data.thunk = thunk;
51    compar_data.compar = compar;
52    qsort_r(base, nel, width, compar_wrapper, &compar_data);
53}
54
55#else
56
57/*
58 * Emulate qsort_r using thread local storage to access the thunk data.
59 */
60
61#include <cutils/threads.h>
62
63static thread_store_t compar_data_key = THREAD_STORE_INITIALIZER;
64
65struct compar_data {
66    void* thunk;
67    int (*compar)(void*, const void* , const void*);
68};
69
70static int compar_wrapper(const void* a, const void* b) {
71    struct compar_data* compar_data = (struct compar_data*)thread_store_get(&compar_data_key);
72    return compar_data->compar(compar_data->thunk, a, b);
73}
74
75void qsort_r_compat(void* base, size_t nel, size_t width, void* thunk,
76        int (*compar)(void*, const void* , const void*)) {
77    struct compar_data compar_data;
78    compar_data.thunk = thunk;
79    compar_data.compar = compar;
80    thread_store_set(&compar_data_key, &compar_data, NULL);
81    qsort(base, nel, width, compar_wrapper);
82}
83
84#endif
85