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 int read_encrypted_file(fz_stream *stm, unsigned char *buf, int len){
        int n=0;
        rimage_aesd *aesd = (rimage_aesd *)stm->state;//get aesd from stm

        int64_t toPos;//position to read to from decryptedBuffer
        int64_t fromPos;//position to read from in decrypted buffer
        int whence = 0;
        int whence1 = 0;
        int lastSeekPos = stm->pos;
        int64_t blockStartPoint = 0;
        int64_t block_num = findBlocNum(stm->pos);//depending on the fileHandler position

        blockStartPoint = block_num*BLOCK_SIZE;

        aesd->blockNum = block_num;
        fromPos = stm->pos - blockStartPoint;
        toPos = fromPos + len;
        if(lastSeekPos > aesd->contentSize){
                //return -1;
        }
        whence = stm->pos - blockStartPoint;
        //lseek(aesd->filehandle, 1, -whence);//seek to block start to read data
        lseek(aesd->filehandle, 0, blockStartPoint);

        read(aesd->filehandle, aesd->encryptedBuffer, BLOCK_SIZE);
        rimage_decrypt_block(aesd);
        //to handle scenario where some data is in this block and remaining in next block
        if(toPos > BLOCK_SIZE){
                n += copy_decrypted_data(buf,aesd,fromPos,BLOCK_SIZE,n);
                aesd->blockNum++;
                read(aesd->filehandle, aesd->encryptedBuffer, BLOCK_SIZE);
                rimage_decrypt_block(aesd);
                toPos = len - n;
                fromPos = 0;

                if( (aesd->blockNum * BLOCK_SIZE) + toPos > aesd->contentSize){
                        toPos = toPos - ((aesd->blockNum * BLOCK_SIZE) + toPos - aesd->contentSize);
                }
        }else{
                if(lastSeekPos+len > aesd->contentSize){
                        toPos = toPos - (lastSeekPos+len - aesd->contentSize);

                }
        }

        n += copy_decrypted_data(buf,aesd,fromPos,toPos,n);

        whence = lastSeekPos + n;
        lseek(aesd->filehandle, 0, whence);//set file handle position correctly
        fz_assert_lock_held(stm->ctx, FZ_LOCK_FILE);
        if (n < 0)
                fz_throw(stm->ctx, "read error: %s", strerror(errno));
        return n;
 }