From f933441648ef6a71dee783d733aac17b9508b452 Mon Sep 17 00:00:00 2001
From: Andreas Huber <andih@google.com>
Date: Wed, 15 Dec 2010 15:17:42 -0800
Subject: Initial support for a true streaming player for mpeg2 transport
 streams.

Change-Id: I153eec439d260a5524b21270e16d36940ec3161a
---
 .../foundation/AHierarchicalStateMachine.cpp       | 97 ++++++++++++++++++++++
 1 file changed, 97 insertions(+)
 create mode 100644 media/libstagefright/foundation/AHierarchicalStateMachine.cpp

(limited to 'media/libstagefright/foundation/AHierarchicalStateMachine.cpp')

diff --git a/media/libstagefright/foundation/AHierarchicalStateMachine.cpp b/media/libstagefright/foundation/AHierarchicalStateMachine.cpp
new file mode 100644
index 0000000..30286d8
--- /dev/null
+++ b/media/libstagefright/foundation/AHierarchicalStateMachine.cpp
@@ -0,0 +1,97 @@
+#include <media/stagefright/foundation/AHierarchicalStateMachine.h>
+
+#include <media/stagefright/foundation/ADebug.h>
+#include <media/stagefright/foundation/AMessage.h>
+#include <utils/Vector.h>
+
+namespace android {
+
+AState::AState(const sp<AState> &parentState)
+    : mParentState(parentState) {
+}
+
+AState::~AState() {
+}
+
+sp<AState> AState::parentState() {
+    return mParentState;
+}
+
+void AState::stateEntered() {
+}
+
+void AState::stateExited() {
+}
+
+////////////////////////////////////////////////////////////////////////////////
+
+AHierarchicalStateMachine::AHierarchicalStateMachine() {
+}
+
+AHierarchicalStateMachine::~AHierarchicalStateMachine() {
+}
+
+void AHierarchicalStateMachine::onMessageReceived(const sp<AMessage> &msg) {
+    sp<AState> save = mState;
+
+    sp<AState> cur = mState;
+    while (cur != NULL && !cur->onMessageReceived(msg)) {
+        // If you claim not to have handled the message you shouldn't
+        // have called setState...
+        CHECK(save == mState);
+
+        cur = cur->parentState();
+    }
+
+    if (cur != NULL) {
+        return;
+    }
+
+    LOGW("Warning message %s unhandled in root state.",
+         msg->debugString().c_str());
+}
+
+void AHierarchicalStateMachine::changeState(const sp<AState> &state) {
+    if (state == mState) {
+        // Quick exit for the easy case.
+        return;
+    }
+
+    Vector<sp<AState> > A;
+    sp<AState> cur = mState;
+    for (;;) {
+        A.push(cur);
+        if (cur == NULL) {
+            break;
+        }
+        cur = cur->parentState();
+    }
+
+    Vector<sp<AState> > B;
+    cur = state;
+    for (;;) {
+        B.push(cur);
+        if (cur == NULL) {
+            break;
+        }
+        cur = cur->parentState();
+    }
+
+    // Remove the common tail.
+    while (A.size() > 0 && B.size() > 0 && A.top() == B.top()) {
+        A.pop();
+        B.pop();
+    }
+
+    mState = state;
+
+    for (size_t i = 0; i < A.size(); ++i) {
+        A.editItemAt(i)->stateExited();
+    }
+
+    for (size_t i = B.size(); i-- > 0;) {
+        B.editItemAt(i)->stateEntered();
+    }
+}
+
+}  // namespace android
-- 
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