1 files changed, 161 insertions, 0 deletions
diff --git a/media/libstagefright/codecs/mp3dec/src/pvmp3_crc.cpp b/media/libstagefright/codecs/mp3dec/src/pvmp3_crc.cpp
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+++ b/media/libstagefright/codecs/mp3dec/src/pvmp3_crc.cpp
@@ -0,0 +1,161 @@
+/* ------------------------------------------------------------------
+ * Copyright (C) 1998-2009 PacketVideo
+ *
+ * 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.
+ * -------------------------------------------------------------------
+ */
+/*
+------------------------------------------------------------------------------
+
+   PacketVideo Corp.
+   MP3 Decoder Library
+
+   Filename: pvmp3_crc.cpp
+
+   Functions:
+        getbits_crc
+        calculate_crc
+
+     Date: 09/21/2007
+
+------------------------------------------------------------------------------
+ REVISION HISTORY
+
+
+ Description:
+
+------------------------------------------------------------------------------
+ INPUT AND OUTPUT DEFINITIONS
+
+getbits_crc
+
+Input
+    tbits *inputStream,     bit stream structure
+    int32 neededBits,       number of bits to read from the bit stream
+    uint32 *crc,            memory location holding calculated crc value
+    uint32 crc_enabled      flag to enable/disable crc checking
+
+------------------------------------------------------------------------------
+ INPUT AND OUTPUT DEFINITIONS
+
+calculate_crc
+
+Input
+    uint32 data,            data vector
+    uint32 length,          number of element upon the crc will be calculated
+    uint32 *crc,            memory location holding calculated crc value
+
+------------------------------------------------------------------------------
+ FUNCTION DESCRIPTION
+
+
+------------------------------------------------------------------------------
+ REQUIREMENTS
+
+
+------------------------------------------------------------------------------
+ REFERENCES
+
+ [1] ISO MPEG Audio Subgroup Software Simulation Group (1996)
+     ISO 13818-3 MPEG-2 Audio Decoder - Lower Sampling Frequency Extension
+
+------------------------------------------------------------------------------
+ PSEUDO-CODE
+
+ ------------------------------------------------------------------------------
+*/
+
+
+/*----------------------------------------------------------------------------
+; INCLUDES
+----------------------------------------------------------------------------*/
+
+#include "pvmp3_getbits.h"
+#include "pvmp3_crc.h"
+
+/*----------------------------------------------------------------------------
+; MACROS
+; Define module specific macros here
+----------------------------------------------------------------------------*/
+
+
+/*----------------------------------------------------------------------------
+; DEFINES
+; Include all pre-processor statements here. Include conditional
+; compile variables also.
+----------------------------------------------------------------------------*/
+
+/*----------------------------------------------------------------------------
+; LOCAL FUNCTION DEFINITIONS
+; Function Prototype declaration
+----------------------------------------------------------------------------*/
+
+/*----------------------------------------------------------------------------
+; LOCAL STORE/BUFFER/POINTER DEFINITIONS
+; Variable declaration - defined here and used outside this module
+----------------------------------------------------------------------------*/
+
+/*----------------------------------------------------------------------------
+; EXTERNAL FUNCTION REFERENCES
+; Declare functions defined elsewhere and referenced in this module
+----------------------------------------------------------------------------*/
+
+/*----------------------------------------------------------------------------
+; EXTERNAL GLOBAL STORE/BUFFER/POINTER REFERENCES
+; Declare variables used in this module but defined elsewhere
+----------------------------------------------------------------------------*/
+
+/*----------------------------------------------------------------------------
+; FUNCTION CODE
+----------------------------------------------------------------------------*/
+
+uint32 getbits_crc(tmp3Bits *inputStream,  /* bit stream structure */
+                   int32 neededBits, /* number of bits to read from the bit stream */
+                   uint32 *crc,
+                   uint32 crc_enabled)
+{
+    uint32 bits = getNbits(inputStream, neededBits);
+
+    if (crc_enabled)
+    {
+        calculate_crc(bits, neededBits, crc);
+    }
+    return(bits);
+}
+
+/*----------------------------------------------------------------------------
+; FUNCTION CODE
+----------------------------------------------------------------------------*/
+
+void calculate_crc(uint32 data,
+                   uint32 length,
+                   uint32 *crc)
+{
+    uint32  carry;
+    uint32  masking = 1 << length;
+
+    while ((masking >>= 1))
+    {
+        carry = *crc & 0x8000;
+        *crc <<= 1;
+        if (!carry ^ !(data & masking))
+        {
+            *crc ^= CRC16_POLYNOMIAL;
+        }
+    }
+    *crc &= 0xffff;
+}
+
+
+