git-svn-id: http://webrtc.googlecode.com/svn/trunk@4 4adac7df-926f-26a2-2b94-8c16560cd09d

modules/audio_processing/utility/ring_buffer.c

@@ -0,0 +1,239 @@
+/*
+ *  Copyright (c) 2011 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+/*
+ * Provides a generic ring buffer that can be written to and read from with
+ * arbitrarily sized blocks. The AEC uses this for several different tasks.
+ */
+
+#include <stdlib.h>
+#include <string.h>
+#include "ring_buffer.h"
+
+typedef struct {
+    int readPos;
+    int writePos;
+    int size;
+    char rwWrap;
+    bufdata_t *data;
+} buf_t;
+
+enum {SAME_WRAP, DIFF_WRAP};
+
+int WebRtcApm_CreateBuffer(void **bufInst, int size)
+{
+    buf_t *buf = NULL;
+
+    if (size < 0) {
+        return -1;
+    }
+
+    buf = malloc(sizeof(buf_t));
+    *bufInst = buf;
+    if (buf == NULL) {
+        return -1;
+    }
+
+    buf->data = malloc(size*sizeof(bufdata_t));
+    if (buf->data == NULL) {
+        free(buf);
+        buf = NULL;
+        return -1;
+    }
+
+    buf->size = size;
+    return 0;
+}
+
+int WebRtcApm_InitBuffer(void *bufInst)
+{
+    buf_t *buf = (buf_t*)bufInst;
+
+    buf->readPos = 0;
+    buf->writePos = 0;
+    buf->rwWrap = SAME_WRAP;
+
+    // Initialize buffer to zeros
+    memset(buf->data, 0, sizeof(bufdata_t)*buf->size);
+
+    return 0;
+}
+
+int WebRtcApm_FreeBuffer(void *bufInst)
+{
+    buf_t *buf = (buf_t*)bufInst;
+
+    if (buf == NULL) {
+        return -1;
+    }
+
+    free(buf->data);
+    free(buf);
+
+    return 0;
+}
+
+int WebRtcApm_ReadBuffer(void *bufInst, bufdata_t *data, int size)
+{
+    buf_t *buf = (buf_t*)bufInst;
+    int n = 0, margin = 0;
+
+    if (size <= 0 || size > buf->size) {
+        return -1;
+    }
+
+    n = size;
+    if (buf->rwWrap == DIFF_WRAP) {
+        margin = buf->size - buf->readPos;
+        if (n > margin) {
+            buf->rwWrap = SAME_WRAP;
+            memcpy(data, buf->data + buf->readPos,
+                sizeof(bufdata_t)*margin);
+            buf->readPos = 0;
+            n = size - margin;
+        }
+        else {
+            memcpy(data, buf->data + buf->readPos,
+                sizeof(bufdata_t)*n);
+            buf->readPos += n;
+            return n;
+        }
+    }
+
+    if (buf->rwWrap == SAME_WRAP) {
+        margin = buf->writePos - buf->readPos;
+        if (margin > n)
+            margin = n;
+        memcpy(data + size - n, buf->data + buf->readPos,
+            sizeof(bufdata_t)*margin);
+        buf->readPos += margin;
+        n -= margin;
+    }
+
+    return size - n;
+}
+
+int WebRtcApm_WriteBuffer(void *bufInst, const bufdata_t *data, int size)
+{
+    buf_t *buf = (buf_t*)bufInst;
+    int n = 0, margin = 0;
+
+    if (size < 0 || size > buf->size) {
+        return -1;
+    }
+
+    n = size;
+    if (buf->rwWrap == SAME_WRAP) {
+        margin = buf->size - buf->writePos;
+        if (n > margin) {
+            buf->rwWrap = DIFF_WRAP;
+            memcpy(buf->data + buf->writePos, data,
+                sizeof(bufdata_t)*margin);
+            buf->writePos = 0;
+            n = size - margin;
+        }
+        else {
+            memcpy(buf->data + buf->writePos, data,
+                sizeof(bufdata_t)*n);
+            buf->writePos += n;
+            return n;
+        }
+    }
+
+    if (buf->rwWrap == DIFF_WRAP) {
+        margin = buf->readPos - buf->writePos;
+        if (margin > n)
+            margin = n;
+        memcpy(buf->data + buf->writePos, data + size - n,
+            sizeof(bufdata_t)*margin);
+        buf->writePos += margin;
+        n -= margin;
+    }
+
+    return size - n;
+}
+
+int WebRtcApm_FlushBuffer(void *bufInst, int size)
+{
+    buf_t *buf = (buf_t*)bufInst;
+    int n = 0, margin = 0;
+
+    if (size <= 0 || size > buf->size) {
+        return -1;
+    }
+
+    n = size;
+    if (buf->rwWrap == DIFF_WRAP) {
+        margin = buf->size - buf->readPos;
+        if (n > margin) {
+            buf->rwWrap = SAME_WRAP;
+            buf->readPos = 0;
+            n = size - margin;
+        }
+        else {
+            buf->readPos += n;
+            return n;
+        }
+    }
+
+    if (buf->rwWrap == SAME_WRAP) {
+        margin = buf->writePos - buf->readPos;
+        if (margin > n)
+            margin = n;
+        buf->readPos += margin;
+        n -= margin;
+    }
+
+    return size - n;
+}
+
+int WebRtcApm_StuffBuffer(void *bufInst, int size)
+{
+    buf_t *buf = (buf_t*)bufInst;
+    int n = 0, margin = 0;
+
+    if (size <= 0 || size > buf->size) {
+        return -1;
+    }
+
+    n = size;
+    if (buf->rwWrap == SAME_WRAP) {
+        margin = buf->readPos;
+        if (n > margin) {
+            buf->rwWrap = DIFF_WRAP;
+            buf->readPos = buf->size - 1;
+            n -= margin + 1;
+        }
+        else {
+            buf->readPos -= n;
+            return n;
+        }
+    }
+
+    if (buf->rwWrap == DIFF_WRAP) {
+        margin = buf->readPos - buf->writePos;
+        if (margin > n)
+            margin = n;
+        buf->readPos -= margin;
+        n -= margin;
+    }
+
+    return size - n;
+}
+
+int WebRtcApm_get_buffer_size(const void *bufInst)
+{
+    const buf_t *buf = (buf_t*)bufInst;
+
+    if (buf->rwWrap == SAME_WRAP)
+        return buf->writePos - buf->readPos;
+    else
+        return buf->size - buf->readPos + buf->writePos;
+}