X-Git-Url: https://gerrit.fd.io/r/gitweb?a=blobdiff_plain;f=src%2Fsvm%2Fsvm_fifo.h;h=d06d77a42f712d9f184ab5a87dd431074fb73580;hb=58d36f02b45c5af38b7df81fb7976129cad3e05b;hp=84901d022d6aaf8a3a5f21770363cb38d78d89ff;hpb=818eb54de01459ed3d823f8a9781bbed0845db82;p=vpp.git

diff --git a/src/svm/svm_fifo.h b/src/svm/svm_fifo.h
index 84901d022d6..d06d77a42f7 100644
--- a/src/svm/svm_fifo.h
+++ b/src/svm/svm_fifo.h
@@ -140,7 +140,7 @@ svm_fifo_t *svm_fifo_create (u32 data_size_in_bytes);
 void svm_fifo_free (svm_fifo_t * f);
 
 int svm_fifo_enqueue_nowait (svm_fifo_t * f, u32 max_bytes,
-			     u8 * copy_from_here);
+			     const u8 * copy_from_here);
 int svm_fifo_enqueue_with_offset (svm_fifo_t * f, u32 offset,
 				  u32 required_bytes, u8 * copy_from_here);
 int svm_fifo_dequeue_nowait (svm_fifo_t * f, u32 max_bytes, u8 * copy_here);
@@ -167,6 +167,49 @@ svm_fifo_newest_ooo_segment_reset (svm_fifo_t * f)
   f->ooos_newest = OOO_SEGMENT_INVALID_INDEX;
 }
 
+/**
+ * Max contiguous chunk of data that can be read
+ */
+always_inline u32
+svm_fifo_max_read_chunk (svm_fifo_t * f)
+{
+  return ((f->tail > f->head) ? (f->tail - f->head) : (f->nitems - f->head));
+}
+
+/**
+ * Max contiguous chunk of data that can be written
+ */
+always_inline u32
+svm_fifo_max_write_chunk (svm_fifo_t * f)
+{
+  return ((f->tail >= f->head) ? (f->nitems - f->tail) : (f->head - f->tail));
+}
+
+/**
+ * Advance tail pointer
+ *
+ * Useful for moving tail pointer after external enqueue.
+ */
+always_inline void
+svm_fifo_enqueue_nocopy (svm_fifo_t * f, u32 bytes)
+{
+  ASSERT (bytes <= svm_fifo_max_enqueue (f));
+  f->tail = (f->tail + bytes) % f->nitems;
+  f->cursize += bytes;
+}
+
+always_inline u8 *
+svm_fifo_head (svm_fifo_t * f)
+{
+  return (f->data + f->head);
+}
+
+always_inline u8 *
+svm_fifo_tail (svm_fifo_t * f)
+{
+  return (f->data + f->tail);
+}
+
 always_inline u32
 ooo_segment_distance_from_tail (svm_fifo_t * f, u32 pos)
 {