1/*
2 * Copyright (c) 2004 Fran��ois Revol <revol@free.fr>
3 *
4 * This file is part of FFmpeg.
5 *
6 * FFmpeg is free software; you can redistribute it and/or
7 * modify it under the terms of the GNU Lesser General Public
8 * License as published by the Free Software Foundation; either
9 * version 2.1 of the License, or (at your option) any later version.
10 *
11 * FFmpeg is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
14 * Lesser General Public License for more details.
15 *
16 * You should have received a copy of the GNU Lesser General Public
17 * License along with FFmpeg; if not, write to the Free Software
18 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
19 */
20//#define DEBUG
21
22#include "avcodec.h"
23
24#include <OS.h>
25
26typedef struct ThreadContext{
27    AVCodecContext *avctx;
28    thread_id thread;
29    sem_id work_sem;
30    sem_id done_sem;
31    int (*func)(AVCodecContext *c, void *arg);
32    void *arg;
33    int ret;
34}ThreadContext;
35
36// it's odd Be never patented that :D
37struct benaphore {
38        vint32 atom;
39        sem_id sem;
40};
41static inline int lock_ben(struct benaphore *ben)
42{
43        if (atomic_add(&ben->atom, 1) > 0)
44                return acquire_sem(ben->sem);
45        return B_OK;
46}
47static inline int unlock_ben(struct benaphore *ben)
48{
49        if (atomic_add(&ben->atom, -1) > 1)
50                return release_sem(ben->sem);
51        return B_OK;
52}
53
54static struct benaphore av_thread_lib_ben;
55
56static int32 ff_thread_func(void *v){
57    ThreadContext *c= v;
58
59    for(;;){
60//printf("thread_func %X enter wait\n", (int)v); fflush(stdout);
61        acquire_sem(c->work_sem);
62//printf("thread_func %X after wait (func=%X)\n", (int)v, (int)c->func); fflush(stdout);
63        if(c->func)
64            c->ret= c->func(c->avctx, c->arg);
65        else
66            return 0;
67//printf("thread_func %X signal complete\n", (int)v); fflush(stdout);
68        release_sem(c->done_sem);
69    }
70
71    return B_OK;
72}
73
74/**
75 * Free what has been allocated by avcodec_thread_init().
76 * Must be called after decoding has finished, especially do not call while avcodec_thread_execute() is running.
77 */
78void avcodec_thread_free(AVCodecContext *s){
79    ThreadContext *c= s->thread_opaque;
80    int i;
81    int32 ret;
82
83    for(i=0; i<s->thread_count; i++){
84
85        c[i].func= NULL;
86        release_sem(c[i].work_sem);
87        wait_for_thread(c[i].thread, &ret);
88        if(c[i].work_sem > B_OK) delete_sem(c[i].work_sem);
89        if(c[i].done_sem > B_OK) delete_sem(c[i].done_sem);
90    }
91
92    av_freep(&s->thread_opaque);
93}
94
95static int avcodec_thread_execute(AVCodecContext *s, int (*func)(AVCodecContext *c2, void *arg2),void *arg, int *ret, int count, int size){
96    ThreadContext *c= s->thread_opaque;
97    int i;
98
99    assert(s == c->avctx);
100    assert(count <= s->thread_count);
101
102    /* note, we can be certain that this is not called with the same AVCodecContext by different threads at the same time */
103
104    for(i=0; i<count; i++){
105        c[i].arg= (char*)arg + i*size;
106        c[i].func= func;
107        c[i].ret= 12345;
108
109        release_sem(c[i].work_sem);
110    }
111    for(i=0; i<count; i++){
112        acquire_sem(c[i].done_sem);
113
114        c[i].func= NULL;
115        if(ret) ret[i]= c[i].ret;
116    }
117    return 0;
118}
119
120int avcodec_thread_init(AVCodecContext *s, int thread_count){
121    int i;
122    ThreadContext *c;
123
124    s->thread_count= thread_count;
125
126    if (thread_count <= 1)
127        return 0;
128
129    assert(!s->thread_opaque);
130    c= av_mallocz(sizeof(ThreadContext)*thread_count);
131    s->thread_opaque= c;
132
133    for(i=0; i<thread_count; i++){
134//printf("init semaphors %d\n", i); fflush(stdout);
135        c[i].avctx= s;
136
137        if((c[i].work_sem = create_sem(0, "ff work sem")) < B_OK)
138            goto fail;
139        if((c[i].done_sem = create_sem(0, "ff done sem")) < B_OK)
140            goto fail;
141
142//printf("create thread %d\n", i); fflush(stdout);
143        c[i].thread = spawn_thread(ff_thread_func, "libavcodec thread", B_LOW_PRIORITY, &c[i] );
144        if( c[i].thread < B_OK ) goto fail;
145        resume_thread(c[i].thread );
146    }
147//printf("init done\n"); fflush(stdout);
148
149    s->execute= avcodec_thread_execute;
150
151    return 0;
152fail:
153    avcodec_thread_free(s);
154    return -1;
155}
156
157/* provide a mean to serialize calls to avcodec_*() for thread safety. */
158
159int avcodec_thread_lock_lib(void)
160{
161        return lock_ben(&av_thread_lib_ben);
162}
163
164int avcodec_thread_unlock_lib(void)
165{
166        return unlock_ben(&av_thread_lib_ben);
167}
168
169/* our versions of _init and _fini (which are called by those actually from crt.o) */
170
171void initialize_after(void)
172{
173        av_thread_lib_ben.atom = 0;
174        av_thread_lib_ben.sem = create_sem(0, "libavcodec benaphore");
175}
176
177void uninitialize_before(void)
178{
179        delete_sem(av_thread_lib_ben.sem);
180}
181
182
183
184