aboutsummaryrefslogtreecommitdiffstats
path: root/libavcodec/pthread.c
blob: 6f98dc41f4e0965f0ae27c4f23187501fab8e823 (plain) (blame)
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
/*
 * Copyright (c) 2004 Michael Niedermayer <michaelni@gmx.at>
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2 of the License, or (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 *
 */
#include <semaphore.h>
#include <pthread.h>

//#define DEBUG

#include "avcodec.h"
#include "common.h"


typedef struct ThreadContext{
    AVCodecContext *avctx;
    pthread_t thread;
    sem_t work_sem;
    sem_t done_sem;
    int (*func)(AVCodecContext *c, void *arg);
    void *arg;
    int ret;
}ThreadContext;

static void * thread_func(void *v){
    ThreadContext *c= v;

    for(;;){
//printf("thread_func %X enter wait\n", (int)v); fflush(stdout);
        sem_wait(&c->work_sem);
//printf("thread_func %X after wait (func=%X)\n", (int)v, (int)c->func); fflush(stdout);
        if(c->func)
            c->ret= c->func(c->avctx, c->arg);
        else
            return NULL;
//printf("thread_func %X signal complete\n", (int)v); fflush(stdout);
        sem_post(&c->done_sem);
    }
    
    return NULL;
}

/**
 * free what has been allocated by avcodec_pthread_init().
 * must be called after decoding has finished, especially dont call while avcodec_pthread_execute() is running
 */
void avcodec_pthread_free(AVCodecContext *s){
    ThreadContext *c= s->thread_opaque;
    int i;

    for(i=0; i<s->thread_count; i++){
        int val;
        
        sem_getvalue(&c[i].work_sem, &val); assert(val == 0);
        sem_getvalue(&c[i].done_sem, &val); assert(val == 0);

        c[i].func= NULL;
        sem_post(&c[i].work_sem);
        pthread_join(c[i].thread, NULL);
        sem_destroy(&c[i].work_sem);
        sem_destroy(&c[i].done_sem);
    }

    av_freep(&s->thread_opaque);
}

int avcodec_pthread_execute(AVCodecContext *s, int (*func)(AVCodecContext *c2, void *arg2),void **arg, int *ret, int count){
    ThreadContext *c= s->thread_opaque;
    int i, val;
    
    assert(s == c->avctx);
    assert(count <= s->thread_count);
    
    /* note, we can be certain that this is not called with the same AVCodecContext by different threads at the same time */

    for(i=0; i<count; i++){
        sem_getvalue(&c[i].work_sem, &val); assert(val == 0);
        sem_getvalue(&c[i].done_sem, &val); assert(val == 0);
        
        c[i].arg= arg[i];
        c[i].func= func;
        c[i].ret= 12345;
        sem_post(&c[i].work_sem);
    }
    for(i=0; i<count; i++){
        sem_wait(&c[i].done_sem);

        sem_getvalue(&c[i].work_sem, &val); assert(val == 0);
        sem_getvalue(&c[i].done_sem, &val); assert(val == 0);
        
        c[i].func= NULL;
        if(ret) ret[i]= c[i].ret;
    }
    return 0;
}

int avcodec_pthread_init(AVCodecContext *s, int thread_count){
    int i;
    ThreadContext *c;

    s->thread_count= thread_count;

    assert(!s->thread_opaque);
    c= av_mallocz(sizeof(ThreadContext)*thread_count);
    s->thread_opaque= c;
    
    for(i=0; i<thread_count; i++){
//printf("init semaphors %d\n", i); fflush(stdout);
        c[i].avctx= s;
        if(sem_init(&c[i].work_sem, 0, 0))
            goto fail;
        if(sem_init(&c[i].done_sem, 0, 0))
            goto fail;
//printf("create thread %d\n", i); fflush(stdout);
        if(pthread_create(&c[i].thread, NULL, thread_func, &c[i]))
            goto fail;
    }
//printf("init done\n"); fflush(stdout);
    
    s->execute= avcodec_pthread_execute;

    return 0;
fail:
    avcodec_pthread_free(s);
    return -1;
}