handle emulation_prevention_three_bytes for AVC

bug: 15917805
Change-Id: I824fe7eea807f8faba6b149c31890b7a5df87825

1 files changed, 19 insertions, 3 deletions

diff --git a/include/media/stagefright/foundation/ABitReader.h b/include/media/stagefright/foundation/ABitReader.h
index 5510b12..c3bf0ff 100644
--- a/include/media/stagefright/foundation/ABitReader.h
+++ b/include/media/stagefright/foundation/ABitReader.h
@@ -25,8 +25,10 @@
 
 namespace android {
 
-struct ABitReader {
+class ABitReader {
+public:
     ABitReader(const uint8_t *data, size_t size);
+    virtual ~ABitReader();
 
     uint32_t getBits(size_t n);
     void skipBits(size_t n);
@@ -37,18 +39,32 @@ struct ABitReader {
 
     const uint8_t *data() const;
 
-private:
+protected:
     const uint8_t *mData;
     size_t mSize;
 
     uint32_t mReservoir;  // left-aligned bits
     size_t mNumBitsLeft;
 
-    void fillReservoir();
+    virtual void fillReservoir();
 
     DISALLOW_EVIL_CONSTRUCTORS(ABitReader);
 };
 
+class NALBitReader : public ABitReader {
+public:
+    NALBitReader(const uint8_t *data, size_t size);
+
+    bool atLeastNumBitsLeft(size_t n) const;
+
+private:
+    int32_t mNumZeros;
+
+    virtual void fillReservoir();
+
+    DISALLOW_EVIL_CONSTRUCTORS(NALBitReader);
+};
+
 }  // namespace android
 
 #endif  // A_BIT_READER_H_