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Commit 43b28298 authored by Andreas Huber's avatar Andreas Huber
Browse files

Use binary search to discover closest sync sample index, replace 

assertions with runtime errors in case the file's table of sync sample
indices is not sorted properly.

Change-Id: Ie4446a44e613a8d329ac680c37361d4407d22520
related-to-bug: 5549855
parent 3fb5048b

media/libstagefright/SampleTable.cpp

+25 −24
Original line number Diff line number Diff line
@@ -618,27 +618,26 @@ status_t SampleTable::findSyncSampleNear( 
    }



    uint32_t left = 0;

    while (left < mNumSyncSamples) {

        uint32_t x = mSyncSamples[left];

    uint32_t right = mNumSyncSamples;

    while (left < right) {

        uint32_t center = left + (right - left) / 2;

        uint32_t x = mSyncSamples[center];



        if (x >= start_sample_index) {

        if (start_sample_index < x) {

            right = center;

        } else if (start_sample_index > x) {

            left = center + 1;

        } else {

            left = center;

            break;

        }



        ++left;

    }

    if (left > 0) {

        --left;

    }



    uint32_t x;

    if (mDataSource->readAt(

                mSyncSampleOffset + 8 + left * 4, &x, 4) != 4) {

        return ERROR_IO;

    }

    // Now ssi[left] is the sync sample index just before (or at)

    // start_sample_index.

    // Also start_sample_index < ssi[left + 1], if left + 1 < mNumSyncSamples.



    x = ntohl(x);

    --x;

    uint32_t x = mSyncSamples[left];



    if (left + 1 < mNumSyncSamples) {

        uint32_t y = mSyncSamples[left + 1];
@@ -679,15 +678,13 @@ status_t SampleTable::findSyncSampleNear( 
            if (x > start_sample_index) {

                CHECK(left > 0);



                if (mDataSource->readAt(

                            mSyncSampleOffset + 8 + (left - 1) * 4, &x, 4) != 4) {

                    return ERROR_IO;

                }



                x = ntohl(x);

                --x;

                x = mSyncSamples[left - 1];



                CHECK(x <= start_sample_index);

                if (x > start_sample_index) {

                    // The table of sync sample indices was not sorted

                    // properly.

                    return ERROR_MALFORMED;

                }

            }

            break;

        }
@@ -701,7 +698,11 @@ status_t SampleTable::findSyncSampleNear( 


                x = mSyncSamples[left + 1];



                CHECK(x >= start_sample_index);

                if (x < start_sample_index) {

                    // The table of sync sample indices was not sorted

                    // properly.

                    return ERROR_MALFORMED;

                }

            }



            break;