COSMETICS: tabs --> spaces, some prettyprinting
[ffmpeg.git] / libavcodec / pthread.c
1 /*
2  * Copyright (c) 2004 Roman Shaposhnik.
3  *
4  * Many thanks to Steven M. Schultz for providing clever ideas and
5  * to Michael Niedermayer <michaelni@gmx.at> for writing initial
6  * implementation.
7  *
8  * This library is free software; you can redistribute it and/or
9  * modify it under the terms of the GNU Lesser General Public
10  * License as published by the Free Software Foundation; either
11  * version 2 of the License, or (at your option) any later version.
12  *
13  * This library is distributed in the hope that it will be useful,
14  * but WITHOUT ANY WARRANTY; without even the implied warranty of
15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
16  * Lesser General Public License for more details.
17  *
18  * You should have received a copy of the GNU Lesser General Public
19  * License along with this library; if not, write to the Free Software
20  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
21  *
22  */
23 #include <pthread.h>
24
25 #include "avcodec.h"
26 #include "common.h"
27
28 typedef int (action_t)(AVCodecContext *c, void *arg);
29
30 typedef struct ThreadContext {
31     pthread_t *workers;
32     action_t *func;
33     void **args;
34     int *rets;
35     int rets_count;
36     int job_count;
37
38     pthread_cond_t last_job_cond;
39     pthread_cond_t current_job_cond;
40     pthread_mutex_t current_job_lock;
41     int current_job;
42     int done;
43 } ThreadContext;
44
45 static void* worker(void *v)
46 {
47     AVCodecContext *avctx = v;
48     ThreadContext *c = avctx->thread_opaque;
49     int our_job = c->job_count;
50     int thread_count = avctx->thread_count;
51     int self_id;
52
53     pthread_mutex_lock(&c->current_job_lock);
54     self_id = c->current_job++;
55     for (;;){
56         while (our_job >= c->job_count) {
57             if (c->current_job == thread_count + c->job_count)
58                 pthread_cond_signal(&c->last_job_cond);
59
60             pthread_cond_wait(&c->current_job_cond, &c->current_job_lock);
61             our_job = self_id;
62
63             if (c->done) {
64                 pthread_mutex_unlock(&c->current_job_lock);
65                 return NULL;
66             }
67         }
68         pthread_mutex_unlock(&c->current_job_lock);
69
70         c->rets[our_job%c->rets_count] = c->func(avctx, c->args[our_job]);
71
72         pthread_mutex_lock(&c->current_job_lock);
73         our_job = c->current_job++;
74     }
75 }
76
77 static always_inline void avcodec_thread_park_workers(ThreadContext *c, int thread_count)
78 {
79     pthread_cond_wait(&c->last_job_cond, &c->current_job_lock);
80     pthread_mutex_unlock(&c->current_job_lock);
81 }
82
83 void avcodec_thread_free(AVCodecContext *avctx)
84 {
85     ThreadContext *c = avctx->thread_opaque;
86     int i;
87
88     pthread_mutex_lock(&c->current_job_lock);
89     c->done = 1;
90     pthread_cond_broadcast(&c->current_job_cond);
91     pthread_mutex_unlock(&c->current_job_lock);
92
93     for (i=0; i<avctx->thread_count; i++)
94          pthread_join(c->workers[i], NULL);
95
96     pthread_mutex_destroy(&c->current_job_lock);
97     pthread_cond_destroy(&c->current_job_cond);
98     pthread_cond_destroy(&c->last_job_cond);
99     av_free(c->workers);
100     av_free(c);
101 }
102
103 int avcodec_thread_execute(AVCodecContext *avctx, action_t* func, void **arg, int *ret, int job_count)
104 {
105     ThreadContext *c= avctx->thread_opaque;
106     int dummy_ret;
107
108     if (job_count <= 0)
109         return 0;
110
111     pthread_mutex_lock(&c->current_job_lock);
112
113     c->current_job = avctx->thread_count;
114     c->job_count = job_count;
115     c->args = arg;
116     c->func = func;
117     if (ret) {
118         c->rets = ret;
119         c->rets_count = job_count;
120     } else {
121         c->rets = &dummy_ret;
122         c->rets_count = 1;
123     }
124     pthread_cond_broadcast(&c->current_job_cond);
125
126     avcodec_thread_park_workers(c, avctx->thread_count);
127
128     return 0;
129 }
130
131 int avcodec_thread_init(AVCodecContext *avctx, int thread_count)
132 {
133     int i;
134     ThreadContext *c;
135
136     c = av_mallocz(sizeof(ThreadContext));
137     if (!c)
138         return -1;
139
140     c->workers = av_mallocz(sizeof(pthread_t)*thread_count);
141     if (!c->workers) {
142         av_free(c);
143         return -1;
144     }
145
146     avctx->thread_opaque = c;
147     avctx->thread_count = thread_count;
148     c->current_job = 0;
149     c->job_count = 0;
150     c->done = 0;
151     pthread_cond_init(&c->current_job_cond, NULL);
152     pthread_cond_init(&c->last_job_cond, NULL);
153     pthread_mutex_init(&c->current_job_lock, NULL);
154     pthread_mutex_lock(&c->current_job_lock);
155     for (i=0; i<thread_count; i++) {
156         if(pthread_create(&c->workers[i], NULL, worker, avctx)) {
157            avctx->thread_count = i;
158            pthread_mutex_unlock(&c->current_job_lock);
159            avcodec_thread_free(avctx);
160            return -1;
161         }
162     }
163
164     avcodec_thread_park_workers(c, thread_count);
165
166     avctx->execute = avcodec_thread_execute;
167     return 0;
168 }