source: svn/trunk/newcon3bcm2_21bu/BSEAV/lib/mpeg2_ts_parse/ts_pmt.c

/***************************************************************************
 *     Copyright (c) 2003, Broadcom Corporation
 *     All Rights Reserved
 *     Confidential Property of Broadcom Corporation
 *
 *  THIS SOFTWARE MAY ONLY BE USED SUBJECT TO AN EXECUTED SOFTWARE LICENSE
 *  AGREEMENT  BETWEEN THE USER AND BROADCOM.  YOU HAVE NO RIGHT TO USE OR
 *  EXPLOIT THIS MATERIAL EXCEPT SUBJECT TO THE TERMS OF SUCH AN AGREEMENT.
 *
 * $brcm_Workfile: ts_pmt.c $
 * $brcm_Revision: 1 $
 * $brcm_Date: 2/7/05 11:30p $
 *
 * [File Description:]
 *
 * Revision History:
 *
 * $brcm_Log: /BSEAV/lib/mpeg2_ts_parse/ts_pmt.c $
 * 
 * 1   2/7/05 11:30p dlwin
 * Merge down for release 2005_REFSW_MERGETOMAIN:
 * 
 * Irvine_BSEAVSW_Devel/5   7/6/04 3:54p erickson
 * PR11771: settop api dataflow redesign
 * 
 * Irvine_BSEAVSW_Devel/4   5/4/04 1:52p erickson
 * PR10938: added bounds checking and PMT and PAT validation in order to
 * prevent segfaults on bad data
 *
 * Irvine_BSEAVSW_Devel/3   2/4/04 9:56a erickson
 * PR9217: converted BDBG_ASSERT calls to CHECK calls. Don't assert on bad
 * data.
 *
 * Irvine_BSEAVSW_Devel/2   9/8/03 10:04a marcusk
 * Added routines to get the number of things.
 *
 * Irvine_BSEAVSW_Devel/1   8/29/03 5:05p marcusk
 * Initial Version.
 *
 ***************************************************************************/
#include "bstd.h"
#include "ts_priv.h"
#include "ts_pmt.h"
BDBG_MODULE(ts_pmt);

#define PROGRAM_INFO_LENGTH_OFFSET (TS_PSI_LAST_SECTION_NUMBER_OFFSET+3)
#define PROGRAM_INFO_LENGTH(buf) (TS_READ_16(&buf[PROGRAM_INFO_LENGTH_OFFSET])&0xFFF)
#define DESCRIPTOR_BASE(buf) (&buf[TS_PSI_LAST_SECTION_NUMBER_OFFSET+5])
#define STREAM_BASE(buf) (TS_PSI_LAST_SECTION_NUMBER_OFFSET + 5 + PROGRAM_INFO_LENGTH(buf))

bool TS_PMT_validate(const uint8_t *buf, unsigned bfrSize)
{
        int sectionEnd = TS_PSI_GET_SECTION_LENGTH(buf) + TS_PSI_SECTION_LENGTH_OFFSET;
        int programInfoEnd = PROGRAM_INFO_LENGTH(buf) + PROGRAM_INFO_LENGTH_OFFSET;

        return (buf[0] == 0x2) &&
                sectionEnd < (int)bfrSize &&
                programInfoEnd < (int)bfrSize &&
                programInfoEnd < sectionEnd;
}

static int TS_PMT_P_getStreamByteOffset( const uint8_t *buf, unsigned bfrSize, int streamNum )
{
        int byteOffset;
        int i;

        /* After the last descriptor */
        byteOffset = STREAM_BASE(buf);

        for (i=0; i < streamNum; i++)
        {
                if (byteOffset >= (int)bfrSize || byteOffset >= TS_PSI_MAX_BYTE_OFFSET(buf))
                        return -1;
                byteOffset += 5 + (TS_READ_16( &buf[byteOffset+3] ) & 0xFFF);
        }

        return byteOffset;
}


uint16_t TS_PMT_getPcrPid( const uint8_t *buf, unsigned bfrSize)
{
        BSTD_UNUSED(bfrSize);
        return (uint16_t)(TS_READ_16( &buf[TS_PSI_LAST_SECTION_NUMBER_OFFSET+1] ) & 0x1FFF);
}

TS_PSI_descriptor TS_PMT_getDescriptor( const uint8_t *buf, unsigned bfrSize, int descriptorNum )
{
        const uint8_t *descriptorBase = DESCRIPTOR_BASE(buf);
        uint32_t descriptorsLength = PROGRAM_INFO_LENGTH(buf);

        /* Any time we dereference memory based on the contents of live data,
        we should check. */
        if (descriptorBase - buf >= (int)bfrSize) {
                return NULL;
        }
        bfrSize -= (descriptorBase - buf);
        if (bfrSize < descriptorsLength) {
                BDBG_WRN(("Invalid descriptor length: %d>=%d", descriptorsLength, bfrSize));
                return NULL;
        }
        return TS_P_getDescriptor(descriptorBase, descriptorsLength, descriptorNum);
}

int TS_PMT_getNumStreams( const uint8_t *buf, unsigned bfrSize)
{
        int byteOffset;
        int i = 0;

        byteOffset = STREAM_BASE(buf);

        while (byteOffset < TS_PSI_MAX_BYTE_OFFSET(buf) && byteOffset < (int)bfrSize)
        {
                byteOffset += 5 + (TS_READ_16( &buf[byteOffset+3] ) & 0xFFF);
                i++;
        }

        return i;
}

BERR_Code TS_PMT_getStream( const uint8_t *buf, unsigned bfrSize, int streamNum, TS_PMT_stream *p_stream )
{
        int byteOffset;

        byteOffset = TS_PMT_P_getStreamByteOffset( buf, bfrSize, streamNum );
        if (byteOffset == -1)
                return BERR_INVALID_PARAMETER;

        p_stream->stream_type = buf[byteOffset];
        p_stream->elementary_PID = (uint16_t)(TS_READ_16( &buf[byteOffset+1] ) & 0x1FFF);

        return BERR_SUCCESS;
}

TS_PSI_descriptor TS_PMT_getStreamDescriptor( const uint8_t *buf, unsigned bfrSize, int streamNum, int descriptorNum )
{
        int byteOffset;

        byteOffset = TS_PMT_P_getStreamByteOffset( buf, bfrSize, streamNum );
        if (byteOffset == -1)
                return NULL;

        return (TS_P_getDescriptor(&buf[byteOffset+5], TS_READ_16(&buf[byteOffset+3])&0xFFF, descriptorNum ));
}