From 540dc9643efc866af6e7040634c9d7a17ca6c5b0 Mon Sep 17 00:00:00 2001
From: Jan Breuer <jan.breuer@jaybee.cz>
Date: 周六, 05 12月 2015 21:40:52 +0800
Subject: [PATCH] Fix error queue and resolve #67
---
libscpi/src/fifo.c | 57 ++++++++++++++++++++++++++++++++++++++++++++++++---------
1 files changed, 48 insertions(+), 9 deletions(-)
diff --git a/libscpi/src/fifo.c b/libscpi/src/fifo.c
index a69cf85..a64d351 100644
--- a/libscpi/src/fifo.c
+++ b/libscpi/src/fifo.c
@@ -21,19 +21,37 @@
}
/**
- * Add element to fifo. If fifo is full, remove last element.
+ * Test if fifo is empty
+ * @param fifo
+ * @return
+ */
+scpi_bool_t fifo_is_empty(scpi_fifo_t * fifo) {
+ return fifo->wr == fifo->rd;
+}
+
+/**
+ * Test if fifo is full
+ * @param fifo
+ * @return
+ */
+scpi_bool_t fifo_is_full(scpi_fifo_t * fifo) {
+ return fifo->wr == ((fifo->rd + fifo->size - 1) % (fifo->size));
+}
+
+/**
+ * Add element to fifo. If fifo is full, return FALSE.
* @param fifo
* @param value
- * @return
+ * @return
*/
scpi_bool_t fifo_add(scpi_fifo_t * fifo, int16_t value) {
/* FIFO full? */
- if (fifo->wr == ((fifo->rd + fifo->size) % (fifo->size + 1))) {
- fifo_remove(fifo, NULL);
+ if (fifo_is_full(fifo)) {
+ return FALSE;
}
fifo->data[fifo->wr] = value;
- fifo->wr = (fifo->wr + 1) % (fifo->size + 1);
+ fifo->wr = (fifo->wr + 1) % (fifo->size);
return TRUE;
}
@@ -46,7 +64,7 @@
*/
scpi_bool_t fifo_remove(scpi_fifo_t * fifo, int16_t * value) {
/* FIFO empty? */
- if (fifo->wr == fifo->rd) {
+ if (fifo_is_empty(fifo)) {
return FALSE;
}
@@ -54,7 +72,28 @@
*value = fifo->data[fifo->rd];
}
- fifo->rd = (fifo->rd + 1) % (fifo->size + 1);
+ fifo->rd = (fifo->rd + 1) % (fifo->size);
+
+ return TRUE;
+}
+
+/**
+ * Remove last element from fifo
+ * @param fifo
+ * @param value
+ * @return FALSE - fifo is empty
+ */
+scpi_bool_t fifo_remove_last(scpi_fifo_t * fifo, int16_t * value) {
+ /* FIFO empty? */
+ if (fifo_is_empty(fifo)) {
+ return FALSE;
+ }
+
+ fifo->wr = (fifo->wr + fifo->size - 1) % (fifo->size);
+
+ if (value) {
+ *value = fifo->data[fifo->wr];
+ }
return TRUE;
}
@@ -63,12 +102,12 @@
* Retrive number of elements in fifo
* @param fifo
* @param value
- * @return
+ * @return
*/
scpi_bool_t fifo_count(scpi_fifo_t * fifo, int16_t * value) {
*value = fifo->wr - fifo->rd;
if (*value < 0) {
- *value += (fifo->size + 1);
+ *value += (fifo->size);
}
return TRUE;
}
--
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