Diff: include/mydsc_ring_buffer.h

Revision:

0:71de2d089e41

diff -r 000000000000 -r 71de2d089e41 include/mydsc_ring_buffer.h
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/include/mydsc_ring_buffer.h	Wed Oct 30 17:25:37 2019 +0000
@@ -0,0 +1,83 @@
+/* My Digital Signal Controller library
+ * Copyright (c) 2019, Gastón H. SALAZAR-SILVA
+ * SPDX-License-Identifier: Apache-2.0
+ * 
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * 
+ * You may obtain a copy of the License at http://www.apache.org/licenses/LICENSE-2.0
+ * 
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND,
+ * either express or implied.
+ * 
+ * See the License for the specific language governing permissions and limitations under the License.
+ */
+
+#ifndef MYDSC_RING_BUFFER_H
+#define MYDSC_RING_BUFFER_H
+
+#include <stdint.h>
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+  /**
+   *  @author Gastón H. SALAZAR-SILVA
+   *  @date   10/29/2019
+   *
+   *  @brief  This module.
+   */
+  typedef struct mydsc_ring_buffer {
+    uint32_t max_position;     /**< It is used as a mask for modular arithmetic. Its value should be 2^n - 1. */
+    uint32_t index;     /**< It is the actual position of the last element in the circular buffer. */
+    float   *samples;   /**< The circular buffer is implemented as an array. this array is initializated with mydsc_ring_bufferinit. */
+  } mydsc_ring_buffer_t;
+
+  /**
+   *    @brief  Initialize a ring buffer.
+   *    @param  prb a pointer to a ring buffer.
+   *    @param  size the size of the samples array. Its value should be 2^n.
+   *    @return 0 on success, -1 on error.
+   *
+   *    @author Gastón H. SALAZAR-SILVA
+   *    @date   10/29/2019
+   */
+  int mydsc_ring_buffer_init(mydsc_ring_buffer_t *prb, uint32_t size);
+
+  /**
+   *    @brief  Push a value into a ring buffer.
+   *    @param  ring    a pointer to a ring buffer.
+   *    @param  input   a float to be pushed into the ring buffer.
+   *
+   *    @author Gastón H. SALAZAR-SILVA
+   *    @date   10/29/2019
+   */
+  void mydsc_ring_buffer_push(mydsc_ring_buffer_t *ring, float input);
+
+  /**
+   *    @brief  Return a pointer to a especific sample.
+   *    @param  ring    a pointer to a ring buffer.
+   *    @param  pos     an integer to indicate which sample to point. A negative value is expexted to past samples.
+   *
+   *    @author Gastón H. SALAZAR-SILVA
+   *    @date   10/29/2019
+   */
+  static inline float* mydsc_ring_buffer_sample(mydsc_ring_buffer_t *ring, int32_t pos)
+  {
+    uint32_t  n;
+    
+    n = ring->index + pos;
+    n &= ring->max_position;
+    return &ring->samples[n];
+  }
+
+#ifdef __cplusplus
+}
+#endif
+
+#define $(rb,n) *mydsc_ring_buffersample( &rb, n)
+#define $$(prb,n) *mydsc_ring_buffersample( prb, n)
+
+#endif // MYDSC_RING_BUFFER_H