first lock free ring buffer implementation

1 files changed, 85 insertions, 0 deletions

diff --git a/lf_ring_buffer.h b/lf_ring_buffer.h
new file mode 100644
index 0000000..7c237ab
--- /dev/null
+++ b/lf_ring_buffer.h
@@ -0,0 +1,85 @@
+/*
+ * File     : lf_ring_buffer.h
+ * Author   : Jérémy Zurcher  <jeremy@asynk.ch>
+ * Date     : 05/01/010
+ * License  :
+ *
+ *  Permission is hereby granted, free of charge, to any person obtaining
+ *  a copy of this software and associated documentation files (the
+ *  "Software"), to deal in the Software without restriction, including
+ *  without limitation the rights to use, copy, modify, merge, publish,
+ *  distribute, sublicense, and/or sell copies of the Software, and to
+ *  permit persons to whom the Software is furnished to do so, subject to
+ *  the following conditions:
+ *  
+ *  The above copyright notice and this permission notice shall be
+ *  included in all copies or substantial portions of the Software.
+ *  
+ *  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+ *  EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+ *  MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+ *  NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
+ *  LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
+ *  OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+ *  WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ *
+ */
+
+#ifndef _LF_RING_BUFFER_H_
+#define _LF_RING_BUFFER_H_
+
+# ifdef __cplusplus
+extern "C" {
+# endif /* __cplusplus */
+
+#define BACKOFF_DELAY_INIT  1000
+#define BACKOFF_DELAY_INC   3000
+#define BACKOFF_DELAY_MAX   90000
+
+#define NO_BLOCK    1       /* if buffer is full, leave instead of try again and again */
+#define IS_NOT_BLOCKING( flags ) ( (flags)&NO_BLOCK )
+
+#define RB_DATA_SIZE    63
+typedef char rb_data_t;
+
+typedef struct buffer_el {
+    char status;
+    rb_data_t data[RB_DATA_SIZE];
+} lf_buffer_el_t;
+
+typedef struct ring_buffer {
+    lf_buffer_el_t *buffer; /* buffer data */
+    int n_buf;              /* number of buffers */
+    int read_from;          /* index where to read data from */
+    int write_to;           /* index where to write data to */
+    int write_delay;        /* backoff nanosleep to reduce fast looping when writing */
+    int read_delay;         /* backoff nanosleep to reduce fast looping when reading */
+} lf_ring_buffer_t;
+
+#define IS_AVAILABLE( idx ) (r->buffer[(idx)].status==0)
+#define MARK_AS_FILLED( idx ) { r->buffer[(idx)].status=1; }
+#define MARK_AS_READ( idx ) { r->buffer[(idx)].status=0; }
+
+/* initialize an empty lf_ring_buffer struct */
+lf_ring_buffer_t* lf_ring_buffer_create( int n_buf );
+
+/* destroy an lf_ring_buffer strcture */
+void lf_ring_buffer_destroy( lf_ring_buffer_t *r );
+
+/* write data into the ring buffer
+ * return 0 on success
+ * return -1 if IS_NOT_BLOCKING and buffer is full
+ */
+int lf_ring_buffer_write( lf_ring_buffer_t *r, rb_data_t *data, int flags );
+
+/* read data from the ring buffer
+ * return 0 on success
+ * return -1 if IS_NOT_BLOCKING and buffer is empty
+ */
+int lf_ring_buffer_read( lf_ring_buffer_t *r, rb_data_t *data, int flags );
+
+# ifdef __cplusplus
+}
+# endif /* __cplusplus */
+
+# endif /* _LF_RING_BUFFER_H_ */