2

server-exp2/taskline.c

@@ -0,0 +1,45 @@
+/* task pool management fucntions */
+/* task_pool_init */
+
+#include "common.h"
+#include "taskline.h"
+void task_line_init(task_line_t *tlp, int n)
+{
+    tlp->taskp = calloc(n, sizeof(task_t)); 
+    tlp->cnt = n;                     /* socks holds max of n items */
+    tlp->inpos= tlp->outpos = 0;           /* Empty socks iff inpos== outpos */
+    sem_init(&tlp->mutex, 0, 1);       /* Binary semaphore for locking */
+    sem_init(&tlp->avail, 0, tlp->cnt);/* Initially, socks has cnt empty cell */
+    sem_init(&tlp->ready, 0, 0);     /* Initially, socks has zero data items */
+}
+
+/* Clean up task line */
+void task_line_deinit(task_line_t *tlp)
+{
+    free(tlp->taskp);
+}
+
+/* Insert item onto the rear of task line */
+void task_insert (task_line_t *tlp, task_t item)
+{   sem_wait(&tlp->avail);           /* Wait for available cell */
+    sem_wait(&tlp->mutex);        /* Lock the shared variable inpos pointer */
+    tlp->taskp[tlp->inpos] = item;     /* Insert the item */
+    tlp->inpos =(tlp-> inpos +1)%(tlp->cnt); /* adjuset inpos point */
+    sem_post(&tlp->mutex);          /* Unlock the buffer */
+    sem_post(&tlp->ready);          /* Announce available item */
+}
+ 
+
+/* Remove and return the first item from task_pool */
+task_t task_remove(task_line_t *tlp)
+{
+    task_t item;
+    sem_wait(&tlp->ready);    /* Wait for available item */
+    sem_wait(&tlp->mutex);    /* Lock the shared pointer variable tp->outpos */
+    item = tlp->taskp[tlp->outpos];            /* Remove the item */
+    tlp->outpos=(tlp->outpos+1)%(tlp->cnt);     /* adjuset outpos point */
+    sem_post(&tlp->avail);                    /* Announce available slot */
+    sem_post(&tlp->mutex);  /* Unlock the shared pointer variable tp->outpos */
+    return item;
+}
+