Method getSliceFromSource

framework/data_source/cache/sliceBufferSource.cpp:197–210

    }

    int sliceBufferSource::getSliceFromSource(uint8_t *buffer, uint64_t sliceNum)
    {
        AF_LOGD("%s get slice %llu\n", __func__, sliceNum);
        uint64_t pos = sliceNum * mSliceSize;
        int ret = mSourceCallBack.onReadSource(buffer, mSliceSize, pos);

        if (ret <= 0) {
            return ret;
        }

        int writeSize = writeAt(buffer, ret, pos);
        assert(writeSize == ret);
        return ret;
    }

    int sliceBufferSource::readAt(uint8_t *buffer, int size, uint64_t offset)
    {