Move libnbaio out of AudioFlinger

libnbaio is now a separate shared library from AudioFlinger, rather
than a static library used only by AudioFlinger.

AudioBufferProvider interface is now also independent of AudioFlinger,
moved to include/media/

Change-Id: I9bb62ffbc38d42a38b0af76e66da5e9ab1e0e21b

1 files changed, 80 insertions, 0 deletions

diff --git a/media/libnbaio/LibsndfileSource.cpp b/media/libnbaio/LibsndfileSource.cpp
new file mode 100644
index 0000000..98610e0
--- /dev/null
+++ b/media/libnbaio/LibsndfileSource.cpp
@@ -0,0 +1,80 @@
+/*
+ * Copyright (C) 2012 The Android Open Source Project
+ *
+ * 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.
+ */
+
+#define LOG_TAG "LibsndfileSource"
+//#define LOG_NDEBUG 0
+
+#include <utils/Errors.h>
+#include <utils/Log.h>
+#include <media/nbaio/LibsndfileSource.h>
+
+namespace android {
+
+LibsndfileSource::LibsndfileSource(SNDFILE *sndfile, const SF_INFO &sfinfo, bool loop) :
+    NBAIO_Source(Format_from_SR_C(sfinfo.samplerate, sfinfo.channels)),
+    mSndfile(sndfile),
+    mEstimatedFramesUntilEOF(sfinfo.frames),
+    mLooping(loop && sfinfo.seekable),
+    mReadAnyFramesThisLoopCycle(false)
+{
+}
+
+LibsndfileSource::~LibsndfileSource()
+{
+    // do not close mSndfile; we don't own it
+}
+
+ssize_t LibsndfileSource::availableToRead()
+{
+    // after we reach the presumed EOF, report infinity just in case there's actually more
+    return !mLooping && mEstimatedFramesUntilEOF > 0 ? mEstimatedFramesUntilEOF : SSIZE_MAX;
+}
+
+ssize_t LibsndfileSource::read(void *buffer, size_t count)
+{
+    if (!mNegotiated) {
+        return (ssize_t) NEGOTIATE;
+    }
+    if (mSndfile == NULL) {
+        return (ssize_t) NO_INIT;
+    }
+    sf_count_t actual = sf_readf_short(mSndfile, (short *) buffer, (sf_count_t) count);
+    // Detect EOF by zero frames read, not by mFramesUntilEOF as it could be inaccurate
+    if (actual == 0) {
+        if (mLooping) {
+            if (mReadAnyFramesThisLoopCycle) {
+                (void) sf_seek(mSndfile, (sf_count_t) 0, SEEK_SET);
+                mReadAnyFramesThisLoopCycle = false;
+            } else {
+                // We didn't read any frames during the current loop cycle, so disable
+                // further looping to prevent the caller from busy waiting at read().
+                // This is especially important when looping an empty file.
+                mLooping = false;
+            }
+        }
+    } else {
+        mFramesRead += actual;
+        if (actual >= mEstimatedFramesUntilEOF) {
+            mEstimatedFramesUntilEOF = 0;
+        } else {
+            mEstimatedFramesUntilEOF -= actual;
+        }
+        mReadAnyFramesThisLoopCycle = true;
+    }
+    return actual;
+}
+
+}   // namespace android