int ff_combine_frame(ParseContext *pc, int next, const uint8_t **buf, int *buf_size)

{

    if(pc->overread){

        av_dlog(NULL, "overread %d, state:%X next:%d index:%d o_index:%d\n",

                pc->overread, pc->state, next, pc->index, pc->overread_index);

        av_dlog(NULL, "%X %X %X %X\n", (*buf)[0], (*buf)[1], (*buf)[2], (*buf)[3]);

    }



    /* Copy overread bytes from last frame into buffer. */

    for(; pc->overread>0; pc->overread--){

        pc->buffer[pc->index++]= pc->buffer[pc->overread_index++];

    }



    /* flush remaining if EOF */

    if(!*buf_size && next == END_NOT_FOUND){

        next= 0;

    }



    pc->last_index= pc->index;



    /* copy into buffer end return */

    if(next == END_NOT_FOUND){

        void* new_buffer = av_fast_realloc(pc->buffer, &pc->buffer_size, (*buf_size) + pc->index + FF_INPUT_BUFFER_PADDING_SIZE);



        if(!new_buffer)

            return AVERROR(ENOMEM);

        pc->buffer = new_buffer;

        memcpy(&pc->buffer[pc->index], *buf, *buf_size);

        pc->index += *buf_size;

        return -1;

    }



    *buf_size=

    pc->overread_index= pc->index + next;



    /* append to buffer */

    if(pc->index){

        void* new_buffer = av_fast_realloc(pc->buffer, &pc->buffer_size, next + pc->index + FF_INPUT_BUFFER_PADDING_SIZE);



        if(!new_buffer)

            return AVERROR(ENOMEM);

        pc->buffer = new_buffer;


        memcpy(&pc->buffer[pc->index], *buf, next + FF_INPUT_BUFFER_PADDING_SIZE );

        pc->index = 0;

        *buf= pc->buffer;

    }



    /* store overread bytes */

    for(;next < 0; next++){

        pc->state = (pc->state<<8) | pc->buffer[pc->last_index + next];

        pc->state64 = (pc->state64<<8) | pc->buffer[pc->last_index + next];

        pc->overread++;

    }



    if(pc->overread){

        av_dlog(NULL, "overread %d, state:%X next:%d index:%d o_index:%d\n",

                pc->overread, pc->state, next, pc->index, pc->overread_index);

        av_dlog(NULL, "%X %X %X %X\n", (*buf)[0], (*buf)[1],(*buf)[2],(*buf)[3]);

    }



    return 0;

}