1 files changed, 137 insertions, 0 deletions
diff --git a/worker.c b/worker.c
new file mode 100644
index 0000000..306bc10
--- /dev/null
+++ b/worker.c
@@ -0,0 +1,137 @@
+/*
+ * Copyright 2018 Anton Khirnov <anton@khirnov.net>
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program 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 General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <errno.h>
+#include <pthread.h>
+#include <stdatomic.h>
+#include <stdlib.h>
+
+#include "worker.h"
+
+struct Worker {
+    WorkSource *ws;
+    unsigned int worker_idx;
+    pthread_t thread_id;
+
+    pthread_mutex_t wb_lock;
+    atomic_int job_idx_start;
+    atomic_int job_idx_end;
+};
+
+int tpi_worker_steal_job(Worker *w)
+{
+    int ret = -1;
+
+    pthread_mutex_lock(&w->wb_lock);
+
+    if (w->job_idx_start < w->job_idx_end)
+        ret = --w->job_idx_end;
+
+    pthread_mutex_unlock(&w->wb_lock);
+
+    return ret;
+}
+
+static int worker_get_next_job(Worker *w)
+{
+    int ret = -1;
+
+    pthread_mutex_lock(&w->wb_lock);
+
+    if (w->job_idx_start < w->job_idx_end)
+        ret = w->job_idx_start++;
+
+    pthread_mutex_unlock(&w->wb_lock);
+
+    if (ret < 0)
+        ret = tpi_worksource_steal_job(w->ws, w->worker_idx);
+
+    return ret;
+}
+
+static void *worker_thread(void *arg)
+{
+    Worker *w = arg;
+    int ret;
+
+    while (1) {
+        WorkBatch wb;
+
+        ret = tpi_worksource_wait_jobs(w->ws, w->worker_idx, &wb);
+        if (ret < 0 || wb.finish)
+            break;
+
+        pthread_mutex_lock(&w->wb_lock);
+        atomic_store(&w->job_idx_start, wb.job_idx_start);
+        atomic_store(&w->job_idx_end,   wb.job_idx_end);
+        pthread_mutex_unlock(&w->wb_lock);
+
+        while ((ret = worker_get_next_job(w)) >= 0)
+            wb.job_func(wb.func_arg, ret, w->worker_idx);
+    }
+
+    return NULL;
+}
+
+int tpi_worker_spawn(Worker **pw, unsigned int worker_idx, WorkSource *ws)
+{
+    Worker *w;
+    int ret;
+
+    w = calloc(1, sizeof(*w));
+    if (!w)
+        return -ENOMEM;
+
+    ret = pthread_mutex_init(&w->wb_lock, NULL);
+    if (ret != 0) {
+        ret = -ret;
+        goto fail_free;
+    }
+
+    w->worker_idx = worker_idx;
+    w->ws         = ws;
+
+    atomic_store(&w->job_idx_start, -1);
+    atomic_store(&w->job_idx_end,   -1);
+
+    ret = pthread_create(&w->thread_id, NULL, worker_thread, w);
+    if (ret != 0) {
+        ret = -ret;
+        goto fail_free;
+    }
+
+    *pw = w;
+    return 0;
+fail_free:
+    free(w);
+    return ret;
+}
+
+void tpi_worker_destroy(Worker **pw)
+{
+    Worker *w = *pw;
+
+    if (!w)
+        return;
+
+    pthread_join(w->thread_id, NULL);
+
+    pthread_mutex_destroy(&w->wb_lock);
+
+    free(w);
+    *pw = NULL;
+}