there is the function : decodeURLComponent ,why not encodeURLComponent?

memcpySmallAllowReadWriteOverflow15(dst_pos, src_prev_pos, bytes_to_copy);
            dst_pos += bytes_to_copy;
            ++src_curr_pos;
            src_prev_pos = src_curr_pos;
            *dst_pos = ' ';
            ++dst_pos;
        }
        else if (src_end - src_curr_pos < 3)
        {
            src_curr_pos = src_end;
            break;
        }
        else
        {
            unsigned char high = unhex(src_curr_pos[1]);
            unsigned char low = unhex(src_curr_pos[2]);
            if (high != 0xFF && low != 0xFF)
            {
                unsigned char octet = (high << 4) + low;
                size_t bytes_to_copy = src_curr_pos - src_prev_pos;
                memcpySmallAllowReadWriteOverflow15(dst_pos, src_prev_pos, bytes_to_copy);
                dst_pos += bytes_to_copy;
                *dst_pos = octet;
                ++dst_pos;
                src_prev_pos = src_curr_pos + 3;
            }
            src_curr_pos += 3;
        }
    }
    if (src_prev_pos < src_curr_pos)