Diff: libscpi/fifo.c

Revision:

0:d8aca47812e0

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/libscpi/fifo.c	Fri Nov 14 01:07:59 2014 +0000
@@ -0,0 +1,48 @@
+
+#include "scpi/fifo.h"
+
+void fifo_init(fifo_t * fifo) {
+    fifo->wr = 0;
+    fifo->rd = 0;
+    fifo->size = FIFO_SIZE;
+}
+
+void fifo_clear(fifo_t * fifo) {
+    fifo->wr = 0;
+    fifo->rd = 0;
+}
+
+scpi_bool_t fifo_add(fifo_t * fifo, int16_t value) {
+    /* FIFO full? */
+    if (fifo->wr == ((fifo->rd + fifo->size) % (fifo->size + 1))) {
+        fifo_remove(fifo, NULL);
+    }
+
+    fifo->data[fifo->wr] = value;
+    fifo->wr = (fifo->wr + 1) % (fifo->size + 1);
+
+    return TRUE;
+}
+
+scpi_bool_t fifo_remove(fifo_t * fifo, int16_t * value) {
+    /* FIFO empty? */
+    if (fifo->wr == fifo->rd) {
+        return FALSE;
+    }
+
+    if(value) {
+        *value = fifo->data[fifo->rd];
+    }
+
+    fifo->rd = (fifo->rd + 1) % (fifo->size + 1);
+
+    return TRUE;
+}
+
+scpi_bool_t fifo_count(fifo_t * fifo, int16_t * value) {
+    *value = fifo->wr - fifo->rd;
+    if (*value < 0) {
+        *value += (fifo->size + 1);
+    }
+    return TRUE;
+}