/*------------------------------------------------------------------------------
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-- --
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-- This software is confidential and proprietary and may be used --
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-- only as expressly authorized by a licensing agreement from --
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-- --
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-- Rockchip Products . --
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-- --
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-- (C) COPYRIGHT 2014 ROCKCHIP PRODUCTS --
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-- ALL RIGHTS RESERVED --
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-- --
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-- The entire notice above must be reproduced --
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-- on all copies and should not be removed. --
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-- --
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--------------------------------------------------------------------------------
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--
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-- Description :Jpeg Decoder utils
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--
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------------------------------------------------------------------------------
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--
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--
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--
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------------------------------------------------------------------------------*/
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/*------------------------------------------------------------------------------
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Table of contents
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1. Include headers
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2. External compiler flags
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3. Module defines
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4. Local function prototypes
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5. Functions
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- JpegDecGetByte
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- JpegDecGet2Bytes
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- JpegDecShowBits
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- JpegDecFlushBits
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------------------------------------------------------------------------------*/
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/*------------------------------------------------------------------------------
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1. Include headers
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------------------------------------------------------------------------------*/
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#include "jpegdecutils.h"
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#include "jpegdecmarkers.h"
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/*------------------------------------------------------------------------------
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2. External compiler flags
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--------------------------------------------------------------------------------
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--------------------------------------------------------------------------------
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3. Module defines
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------------------------------------------------------------------------------*/
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/*------------------------------------------------------------------------------
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4. Local function prototypes
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------------------------------------------------------------------------------*/
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/*------------------------------------------------------------------------------
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5. Functions
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------------------------------------------------------------------------------*/
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/*------------------------------------------------------------------------------
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Function name: JpegDecGetByte
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Functional description:
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Reads one byte (8 bits) from stream and returns the bits
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Note! This function does not skip the 0x00 byte if the previous
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byte value was 0xFF!!!
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Inputs:
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StreamStorage *pStream Pointer to structure
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Outputs:
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Returns 8 bit value if ok
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else returns STRM_ERROR (0xFFFFFFFF)
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------------------------------------------------------------------------------*/
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RK_U32 JpegDecGetByte(StreamStorage * pStream)
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{
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RK_U32 tmp;
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if ((pStream->readBits + 8) > (8 * pStream->streamLength))
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return (STRM_ERROR);
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tmp = *(pStream->pCurrPos)++;
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tmp = (tmp << 8) | *(pStream->pCurrPos);
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tmp = (tmp >> (8 - pStream->bitPosInByte)) & 0xFF;
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pStream->readBits += 8;
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return (tmp);
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}
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/*------------------------------------------------------------------------------
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Function name: JpegDecGet2Bytes
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Functional description:
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Reads two bytes (16 bits) from stream and returns the bits
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Note! This function does not skip the 0x00 byte if the previous
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byte value was 0xFF!!!
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Inputs:
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StreamStorage *pStream Pointer to structure
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Outputs:
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Returns 16 bit value
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------------------------------------------------------------------------------*/
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RK_U32 JpegDecGet2Bytes(StreamStorage * pStream)
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{
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RK_U32 tmp;
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if ((pStream->readBits + 16) > (8 * pStream->streamLength))
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return (STRM_ERROR);
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tmp = *(pStream->pCurrPos)++;
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tmp = (tmp << 8) | *(pStream->pCurrPos)++;
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tmp = (tmp << 8) | *(pStream->pCurrPos);
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tmp = (tmp >> (8 - pStream->bitPosInByte)) & 0xFFFF;
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pStream->readBits += 16;
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return (tmp);
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}
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/*------------------------------------------------------------------------------
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Function name: JpegDecShowBits
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Functional description:
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Reads 32 bits from stream and returns the bits, does not update
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stream pointers. If there are not enough bits in data buffer it
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reads the rest of the data buffer bits and fills the lsb of return
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value with zero bits.
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Note! This function will skip the byte valued 0x00 if the previous
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byte value was 0xFF!!!
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Inputs:
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StreamStorage *pStream Pointer to structure
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Outputs:
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Returns 32 bit value
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------------------------------------------------------------------------------*/
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RK_U32 JpegDecShowBits(StreamStorage * pStream)
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{
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RK_S32 bits;
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RK_U32 readBits;
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RK_U32 out = 0;
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RK_U8 *pData = pStream->pCurrPos;
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/* bits left in buffer */
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bits = (RK_S32) (8 * pStream->streamLength - pStream->readBits);
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if (!bits)
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return (0);
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readBits = 0;
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do {
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if (pData > pStream->pStartOfStream) {
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/* FF 00 bytes in stream -> jump over 00 byte */
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if ((pData[-1] == 0xFF) && (pData[0] == 0x00)) {
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pData++;
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bits -= 8;
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}
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}
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if (readBits == 32 && pStream->bitPosInByte) {
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out <<= pStream->bitPosInByte;
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out |= *pData >> (8 - pStream->bitPosInByte);
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readBits = 0;
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break;
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}
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out = (out << 8) | *pData++;
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readBits += 8;
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bits -= 8;
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} while (readBits < (32 + pStream->bitPosInByte) && bits > 0);
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if (bits <= 0 &&
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((readBits + pStream->readBits) >= (pStream->streamLength * 8))) {
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/* not enough bits in stream, fill with zeros */
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out = (out << (32 - (readBits - pStream->bitPosInByte)));
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}
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return (out);
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}
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/*------------------------------------------------------------------------------
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Function name: JpegDecFlushBits
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Functional description:
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Updates stream pointers, flushes bits from stream
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Note! This function will skip the byte valued 0x00 if the previous
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byte value was 0xFF!!!
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Inputs:
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StreamStorage *pStream Pointer to structure
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RK_U32 bits Number of bits to be flushed
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Outputs:
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OK
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STRM_ERROR
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------------------------------------------------------------------------------*/
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RK_U32 JpegDecFlushBits(StreamStorage * pStream, RK_U32 bits)
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{
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RK_U32 tmp;
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RK_U32 extraBits = 0;
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if ((pStream->readBits + bits) > (8 * pStream->streamLength)) {
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/* there are not so many bits left in buffer */
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/* stream pointers to the end of the stream */
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/* and return value STRM_ERROR */
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pStream->readBits = 8 * pStream->streamLength;
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pStream->bitPosInByte = 0;
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pStream->pCurrPos = pStream->pStartOfStream + pStream->streamLength;
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return (STRM_ERROR);
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} else {
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tmp = 0;
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while (tmp < bits) {
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if (bits - tmp < 8) {
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if ((8 - pStream->bitPosInByte) > (bits - tmp)) {
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/* inside one byte */
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pStream->bitPosInByte += bits - tmp;
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tmp = bits;
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} else {
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if (pStream->pCurrPos[0] == 0xFF &&
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pStream->pCurrPos[1] == 0x00) {
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extraBits += 8;
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pStream->pCurrPos += 2;
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} else {
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pStream->pCurrPos++;
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}
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tmp += 8 - pStream->bitPosInByte;
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pStream->bitPosInByte = 0;
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pStream->bitPosInByte = bits - tmp;
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tmp = bits;
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}
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} else {
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tmp += 8;
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if (pStream->appnFlag) {
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pStream->pCurrPos++;
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} else {
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if (pStream->pCurrPos[0] == 0xFF &&
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pStream->pCurrPos[1] == 0x00) {
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extraBits += 8;
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pStream->pCurrPos += 2;
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} else {
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pStream->pCurrPos++;
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}
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}
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}
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}
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/* update stream pointers */
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pStream->readBits += bits + extraBits;
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return (OK);
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}
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}
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