From 9744e41c40598c6a0b74440f3b5be63f9f3708a5 Mon Sep 17 00:00:00 2001
From: Fraunhofer IIS FDK <audio-fdk@iis.fraunhofer.de>
Date: Fri, 8 Jun 2018 18:03:16 +0200
Subject: Prevent bit buffer counter overflow.

While long-term test we discovered a bit counter overflow in the bit buffer.
The bit buffer state was only used by HCR and RVLC tool and can easily be substituted with FDKgetValidBits() call.
The following patch completely removes the bit counter and all its obsolete functions.

Bug: 112662184
Test: atest DecoderTestXheAac ; atest DecoderTestAacDrc

Change-Id: Icee0519d26a2aa62367d2dece59cd3d60ffcade7
(cherry picked from commit 15292f7e9620caf9e8df26a62efc2a2891ea822e)
---
 libFDK/src/FDK_bitbuffer.cpp | 29 -----------------------------
 1 file changed, 29 deletions(-)

(limited to 'libFDK/src/FDK_bitbuffer.cpp')

diff --git a/libFDK/src/FDK_bitbuffer.cpp b/libFDK/src/FDK_bitbuffer.cpp
index a990c58..98905ea 100644
--- a/libFDK/src/FDK_bitbuffer.cpp
+++ b/libFDK/src/FDK_bitbuffer.cpp
@@ -128,7 +128,6 @@ void FDK_InitBitBuffer(HANDLE_FDK_BITBUF hBitBuf, UCHAR *pBuffer, UINT bufSize,
   hBitBuf->ValidBits = validBits;
   hBitBuf->ReadOffset = 0;
   hBitBuf->WriteOffset = 0;
-  hBitBuf->BitCnt = 0;
   hBitBuf->BitNdx = 0;
 
   hBitBuf->Buffer = pBuffer;
@@ -151,7 +150,6 @@ void FDK_ResetBitBuffer(HANDLE_FDK_BITBUF hBitBuf) {
   hBitBuf->ValidBits = 0;
   hBitBuf->ReadOffset = 0;
   hBitBuf->WriteOffset = 0;
-  hBitBuf->BitCnt = 0;
   hBitBuf->BitNdx = 0;
 }
 
@@ -161,7 +159,6 @@ INT FDK_get(HANDLE_FDK_BITBUF hBitBuf, const UINT numberOfBits) {
   UINT bitOffset = hBitBuf->BitNdx & 0x07;
 
   hBitBuf->BitNdx = (hBitBuf->BitNdx + numberOfBits) & (hBitBuf->bufBits - 1);
-  hBitBuf->BitCnt += numberOfBits;
   hBitBuf->ValidBits -= numberOfBits;
 
   UINT byteMask = hBitBuf->bufSize - 1;
@@ -184,7 +181,6 @@ INT FDK_get(HANDLE_FDK_BITBUF hBitBuf, const UINT numberOfBits) {
 INT FDK_get32(HANDLE_FDK_BITBUF hBitBuf) {
   UINT BitNdx = hBitBuf->BitNdx + 32;
   hBitBuf->BitNdx = BitNdx & (hBitBuf->bufBits - 1);
-  hBitBuf->BitCnt += 32;
   hBitBuf->ValidBits = (UINT)((INT)hBitBuf->ValidBits - (INT)32);
 
   UINT byteOffset = (BitNdx - 1) >> 3;
@@ -223,7 +219,6 @@ INT FDK_getBwd(HANDLE_FDK_BITBUF hBitBuf, const UINT numberOfBits) {
   int i;
 
   hBitBuf->BitNdx = (hBitBuf->BitNdx - numberOfBits) & (hBitBuf->bufBits - 1);
-  hBitBuf->BitCnt -= numberOfBits;
   hBitBuf->ValidBits += numberOfBits;
 
   UINT tx = hBitBuf->Buffer[(byteOffset - 3) & byteMask] << 24 |
@@ -256,7 +251,6 @@ void FDK_put(HANDLE_FDK_BITBUF hBitBuf, UINT value, const UINT numberOfBits) {
     UINT bitOffset = hBitBuf->BitNdx & 0x7;
 
     hBitBuf->BitNdx = (hBitBuf->BitNdx + numberOfBits) & (hBitBuf->bufBits - 1);
-    hBitBuf->BitCnt += numberOfBits;
     hBitBuf->ValidBits += numberOfBits;
 
     UINT byteMask = hBitBuf->bufSize - 1;
@@ -307,7 +301,6 @@ void FDK_putBwd(HANDLE_FDK_BITBUF hBitBuf, UINT value,
   int i;
 
   hBitBuf->BitNdx = (hBitBuf->BitNdx - numberOfBits) & (hBitBuf->bufBits - 1);
-  hBitBuf->BitCnt -= numberOfBits;
   hBitBuf->ValidBits -= numberOfBits;
 
   /* in place turn around */
@@ -344,7 +337,6 @@ void FDK_putBwd(HANDLE_FDK_BITBUF hBitBuf, UINT value,
 #ifndef FUNCTION_FDK_pushBack
 void FDK_pushBack(HANDLE_FDK_BITBUF hBitBuf, const UINT numberOfBits,
                   UCHAR config) {
-  hBitBuf->BitCnt = (UINT)((INT)hBitBuf->BitCnt - (INT)numberOfBits);
   hBitBuf->ValidBits =
       (config == 0) ? (UINT)((INT)hBitBuf->ValidBits + (INT)numberOfBits)
                     : ((UINT)((INT)hBitBuf->ValidBits - (INT)numberOfBits));
@@ -355,7 +347,6 @@ void FDK_pushBack(HANDLE_FDK_BITBUF hBitBuf, const UINT numberOfBits,
 
 void FDK_pushForward(HANDLE_FDK_BITBUF hBitBuf, const UINT numberOfBits,
                      UCHAR config) {
-  hBitBuf->BitCnt = (UINT)((INT)hBitBuf->BitCnt + (INT)numberOfBits);
   hBitBuf->ValidBits =
       (config == 0) ? ((UINT)((INT)hBitBuf->ValidBits - (INT)numberOfBits))
                     : (UINT)((INT)hBitBuf->ValidBits + (INT)numberOfBits);
@@ -363,19 +354,6 @@ void FDK_pushForward(HANDLE_FDK_BITBUF hBitBuf, const UINT numberOfBits,
       (UINT)((INT)hBitBuf->BitNdx + (INT)numberOfBits) & (hBitBuf->bufBits - 1);
 }
 
-void FDK_byteAlign(HANDLE_FDK_BITBUF hBitBuf, UCHAR config) {
-  INT alignment = hBitBuf->BitCnt & 0x07;
-
-  if (alignment) {
-    if (config == 0)
-      FDK_pushForward(hBitBuf, 8 - alignment, config); /* BS_READER */
-    else
-      FDK_put(hBitBuf, 0, 8 - alignment); /* BS_WRITER */
-  }
-
-  hBitBuf->BitCnt = 0;
-}
-
 #ifndef FUNCTION_FDK_getValidBits
 UINT FDK_getValidBits(HANDLE_FDK_BITBUF hBitBuf) { return hBitBuf->ValidBits; }
 #endif /* #ifndef FUNCTION_FDK_getValidBits */
@@ -384,12 +362,6 @@ INT FDK_getFreeBits(HANDLE_FDK_BITBUF hBitBuf) {
   return (hBitBuf->bufBits - hBitBuf->ValidBits);
 }
 
-void FDK_setBitCnt(HANDLE_FDK_BITBUF hBitBuf, const UINT value) {
-  hBitBuf->BitCnt = value;
-}
-
-INT FDK_getBitCnt(HANDLE_FDK_BITBUF hBitBuf) { return hBitBuf->BitCnt; }
-
 void FDK_Feed(HANDLE_FDK_BITBUF hBitBuf, const UCHAR *RESTRICT inputBuffer,
               const UINT bufferSize, UINT *bytesValid) {
   inputBuffer = &inputBuffer[bufferSize - *bytesValid];
@@ -438,7 +410,6 @@ void CopyAlignedBlock(HANDLE_FDK_BITBUF h_BitBufSrc, UCHAR *RESTRICT dstBuffer,
 
   h_BitBufSrc->BitNdx =
       (h_BitBufSrc->BitNdx + bToRead) & (h_BitBufSrc->bufBits - 1);
-  h_BitBufSrc->BitCnt += bToRead;
   h_BitBufSrc->ValidBits -= bToRead;
 }
 
-- 
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