kdb_plus_fixed/api/

mod.rs

//! This `api` module provides API mirroring the C API of q/kdb+. The expected usage is to build a shared library for q/kdb+ in Rust.
//!
//! In order to avoid writing too large `unsafe` block leading to poor optimization, most of native C API functions were provided
//!  with a wrapper funtion with a bit of ergonomic safety and with intuitive implementation as a trait method. The only exceptions
//!  are:
//! - `knk`
//! - `k`
//!   These functions are using elipsis (`...`) as its argument and cannot be provided with a stable distribution. When you need to use
//!   either of them you can find them under `native` namespace together with the other naked C API functions.
//!
//! *Notes:*
//!
//! - This library is for kdb+ version >= 3.0.
//! - Meangless C macros are excluded but accessors of an underlying array like `kC`, `kJ`, `kK` etc. are provided in Rust way.
//!
//! ## Examples
//!
//! In order to encourage to use Rust style API, examples of the C API style is not provided here (you can see them in [README of the repository](https://github.com/diamondrod/kdbplus)).
//!  The examples below are written without `unsafe` code. You can see how comfortably breathing are the wrapped functions in the code.
//!
//! ```no_run
//! #[macro_use]
//! extern crate kdbplus;
//! use kdbplus::api::*;
//! use kdbplus::qtype;
//!
//! #[no_mangle]
//! pub extern "C" fn create_symbol_list2(_: K) -> K{
//!   let mut list=new_list(qtype::SYMBOL_LIST, 0);
//!   list.push_symbol("Abraham").unwrap();
//!   list.push_symbol("Isaac").unwrap();
//!   list.push_symbol("Jacob").unwrap();
//!   list.push_symbol_n("Josephine", 6).unwrap();
//!   list
//! }
//!
//! #[no_mangle]
//! fn no_panick(func: K, args: K) -> K{
//!   let result=error_to_string(apply(func, args));
//!   if let Ok(error) = result.get_error_string(){
//!     println!("FYI: {}", error);
//!     // Decrement reference count of the error object which is no longer used.
//!     decrement_reference_count(result);
//!     KNULL
//!   }
//!   else{
//!     println!("success!");
//!     result
//!   }
//! }
//!
//! #[no_mangle]
//! pub extern "C" fn create_table2(_: K) -> K{
//!   // Build keys
//!   let keys=new_list(qtype::SYMBOL_LIST, 2);
//!   let keys_slice=keys.as_mut_slice::<S>();
//!   keys_slice[0]=enumerate(str_to_S!("time"));
//!   keys_slice[1]=enumerate_n(str_to_S!("temperature_and_humidity"), 11);
//!
//!   // Build values
//!   let values=new_list(qtype::COMPOUND_LIST, 2);
//!   let time=new_list(qtype::TIMESTAMP_LIST, 3);
//!   // 2003.10.10D02:24:19.167018272 2006.05.24D06:16:49.419710368 2008.08.12D23:12:24.018691392
//!   time.as_mut_slice::<J>().copy_from_slice(&[119067859167018272_i64, 201766609419710368, 271897944018691392]);
//!   let temperature=new_list(qtype::FLOAT_LIST, 3);
//!   temperature.as_mut_slice::<F>().copy_from_slice(&[22.1_f64, 24.7, 30.5]);
//!   values.as_mut_slice::<K>().copy_from_slice(&[time, temperature]);
//!   
//!   flip(new_dictionary(keys, values))
//! }
//! ```
//!
//! And q code is here:
//!
//! ```q
//! q)summon:`libapi_examples 2: (`create_symbol_list2; 1)
//! q)summon[]
//! `Abraham`Isaac`Jacob`Joseph
//! q)chill: `libapi_examples 2: (`no_panick; 2);
//! q)chill[$; ("J"; "42")]
//! success!
//! 42
//! q)chill[+; (1; `a)]
//! FYI: type
//! q)climate_change: libc_api_examples 2: (`create_table2; 1);
//! q)climate_change[]
//! time                          temperature
//! -----------------------------------------
//! 2003.10.10D02:24:19.167018272 22.1       
//! 2006.05.24D06:16:49.419710368 24.7       
//! 2008.08.12D23:12:24.018691392 30.5  
//! ```

//++++++++++++++++++++++++++++++++++++++++++++++++++//
// >> Settings
//++++++++++++++++++++++++++++++++++++++++++++++++++//

#![allow(non_upper_case_globals)]
#![allow(non_camel_case_types)]
#![allow(non_snake_case)]
#![allow(clippy::not_unsafe_ptr_arg_deref)]
#![allow(clippy::wrong_self_convention)]
#![allow(clippy::len_without_is_empty)]

//++++++++++++++++++++++++++++++++++++++++++++++++++//
// >> Load Libraries
//++++++++++++++++++++++++++++++++++++++++++++++++++//

use super::qtype;
use std::convert::TryInto;
use std::ffi::CStr;
use std::os::raw::{
    c_char, c_double, c_float, c_int, c_longlong, c_schar, c_short, c_uchar, c_void,
};
use std::str;
pub mod native;

//++++++++++++++++++++++++++++++++++++++++++++++++++//
// >> Global Variables
//++++++++++++++++++++++++++++++++++++++++++++++++++//

/// `K` nullptr. This value can be used as void value of a function which is called directly by q process
///  and returns `K`. This null pointer is interpreted as a general null value (`::`) whose type is `101h`.
/// # Example
/// ```
/// use kdbplus::api::*;
///
/// #[no_mangle]
/// pub extern "C" fn vanity(_: K) -> K{
///   println!("Initialized something, probably it is your mindset.");
///   KNULL
/// }
/// ```
/// # Warning
/// This value must NOT be used as a returned value for functions called by another function
///  because [`error_to_string`](fn.error_to_string.html) misunderstands the value as an error.
///  For detail, see its warning section.
pub const KNULL: K = 0 as K;

//++++++++++++++++++++++++++++++++++++++++++++++++++//
// >> Macros
//++++++++++++++++++++++++++++++++++++++++++++++++++//

//%% Utility %%//vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv/

/// Convert `&str` to `S` (null-terminated character array).
/// # Example
/// ```no_run
/// #[macro_use]
/// use kdbplus::api::*;
///
/// #[no_mangle]
/// pub extern "C" fn pingpong(_: K) -> K{
///   unsafe{native::k(0, str_to_S!("ping"), new_int(77), KNULL)}
/// }
/// ```
/// ```q
/// q)ping:{[int] `$string[int], "_pong!!"}
/// q)pingpong: `libapi_examples 2: (`pingpong; 1);
/// q)pingpong[]
/// `77_pong!!
/// ```
/// # Note
/// This macro cannot be created as a function due to freeing resource of Rust (not sure).
#[macro_export]
macro_rules! str_to_S {
    ($string: expr) => {
        [$string.as_bytes(), &[b'\0']].concat().as_mut_ptr() as S
    };
}

//++++++++++++++++++++++++++++++++++++++++++++++++++//
// >> Structs
//++++++++++++++++++++++++++++++++++++++++++++++++++//

//%% Alias %%//vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv/

/// `char*` in C. Also used to access symbol of q.
pub type S = *mut c_char;
/// `const char*` in C.
pub type const_S = *const c_char;
/// `char` in C. Also used to access char of q.
pub type C = c_char;
/// `unsigned char` in C. Also used to access byte of q.
pub type G = c_uchar;
/// `i16` in C. Also used to access short of q.
pub type H = c_short;
/// `i32` in C. Also used to access int and compatible types (month, date, minute, second and time) of q.
pub type I = c_int;
/// `i64` in C. Also used to access long and compatible types (timestamp and timespan) of q.
pub type J = c_longlong;
/// `f32` in C. Also used to access real of q.
pub type E = c_float;
/// `f64` in C. Also used to access float and datetime of q.
pub type F = c_double;
/// `void` in C.
pub type V = c_void;

//%% U %%//vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv/

/// Struct representing 16-bytes GUID.
#[derive(Clone, Copy, Debug)]
#[repr(C)]
pub struct U {
    pub guid: [G; 16],
}

//%% K %%//vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv/

/// Underlying list value of q object.
/// # Note
/// Usually this struct does not need to be accessed this struct directly unless user wants to
///  access via a raw pointer for non-trivial stuff.
#[derive(Clone, Copy, Debug)]
#[repr(C)]
pub struct k0_list {
    /// Length of the list.
    pub n: J,
    /// Pointer referring to the head of the list. This pointer will be interpreted
    ///  as various types when accessing `K` object to edit the list with
    ///  [`as_mut_slice`](trait.KUtility.html#tymethod.as_mut_slice).
    pub G0: [G; 1],
}

/// Underlying atom value of q object.
/// # Note
/// Usually this struct does not need to be accessed directly unless user wants to
///  access via a raw pointer for non-trivial stuff.
#[derive(Clone, Copy)]
#[repr(C)]
pub union k0_inner {
    /// Byte type holder.
    pub byte: G,
    /// Short type holder.
    pub short: H,
    /// Int type holder.
    pub int: I,
    /// Long type older.
    pub long: J,
    /// Real type holder.
    pub real: E,
    /// Float type holder.
    pub float: F,
    /// Symbol type holder.
    pub symbol: S,
    /// Table type holder.
    pub table: *mut k0,
    /// List type holder.
    pub list: k0_list,
}

/// Underlying struct of `K` object.
#[repr(C)]
#[derive(Clone, Copy)]
pub struct k0 {
    /// For internal usage.
    m: c_schar,
    /// For internal usage.
    a: c_schar,
    /// Type indicator.
    pub qtype: c_schar,
    /// Attribute of list.
    pub attribute: C,
    /// Reference count of the object.
    pub refcount: I,
    /// Underlying value.
    pub value: k0_inner,
}

/// Struct representing q object.
pub type K = *mut k0;

//++++++++++++++++++++++++++++++++++++++++++++++++++//
// >> Structs
//++++++++++++++++++++++++++++++++++++++++++++++++++//

//%% KUtility %%//vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv/

/// Trait which defines utility methods to manipulate q object.
pub trait KUtility {
    /// Derefer `K` as a mutable slice of the specified type. The supported types are:
    /// - `G`: Equivalent to C API macro `kG`.
    /// - `H`: Equivalent to C API macro `kH`.
    /// - `I`: Equivalent to C API macro `kI`.
    /// - `J`: Equivalent to C API macro `kJ`.
    /// - `E`: Equivalent to C API macro `kE`.
    /// - `F`: Equivalent to C API macro `kF`.
    /// - `C`: Equivalent to C API macro `kC`.
    /// - `S`: Equivalent to C API macro `kS`.
    /// - `K`: Equivalent to C API macro `kK`.
    /// # Example
    /// ```
    /// use kdbplus::api::*;
    ///
    /// #[no_mangle]
    /// pub extern "C" fn modify_long_list_a_bit(long_list: K) -> K{
    ///   if long_list.len() >= 2{
    ///     // Derefer as a mutable i64 slice.
    ///     long_list.as_mut_slice::<J>()[1]=30000_i64;
    ///     // Increment the counter to reuse on q side.
    ///     increment_reference_count(long_list)
    ///   }
    ///   else{
    ///     new_error("this list is not long enough. how ironic...\0")
    ///   }
    /// }
    /// ```
    /// ```q
    /// q)ironic: `libapi_examples 2: (`modify_long_list_a_bit; 1);
    /// q)list:1 2 3;
    /// q)ironic list
    /// 1 30000 3
    /// q)ironic enlist 1
    /// ```
    /// # Note
    /// Intuitively the parameter should be `&mut self` but it restricts a manipulating
    ///  `K` objects in the form of slice simultaneously. As copying a pointer is not
    ///  an expensive operation, using `self` should be fine.
    fn as_mut_slice<'a, T>(self) -> &'a mut [T];

    /// Get an underlying q byte.
    /// # Example
    /// ```no_run
    /// use kdbplus::api::*;
    ///
    /// #[no_mangle]
    /// pub extern "C" fn print_bool(atom: K) -> K{
    ///   match atom.get_bool(){
    ///     Ok(boolean) => {
    ///       println!("bool: {}", boolean);
    ///       KNULL
    ///     },
    ///     Err(error) => new_error(error)
    ///   }
    /// }
    /// ```
    /// ```q
    /// q)print_boole: `libapi_examples 2: (`print_bool; 1);
    /// q)print_bool[1b]
    /// bool: true
    /// ```
    fn get_bool(&self) -> Result<bool, &'static str>;

    /// Get an underlying q byte.
    /// # Example
    /// ```no_run
    /// use kdbplus::api::*;
    ///
    /// #[no_mangle]
    /// pub extern "C" fn print_guid(atom: K) -> K{
    ///   match atom.get_guid(){
    ///     Ok(guid) => {
    ///       let strguid=guid.iter().map(|b| format!("{:02x}", b)).collect::<String>();
    ///       println!("GUID: {}-{}-{}-{}-{}", &strguid[0..4], &strguid[4..6], &strguid[6..8], &strguid[8..10], &strguid[10..16]);
    ///       KNULL
    ///     },
    ///     Err(error) => new_error(error)
    ///   }
    /// }
    /// ```
    /// ```q
    /// q)print_guid: `libapi_examples 2: (`print_guid; 1);
    /// q)guid: first 1?0Ng;
    /// q)print_guid[guid]
    /// GUID: 8c6b-8b-64-68-156084
    /// ```
    fn get_guid(&self) -> Result<[u8; 16], &'static str>;

    /// Get an underlying q byte.
    /// # Example
    /// ```no_run
    /// use kdbplus::api::*;
    ///
    /// #[no_mangle]
    /// pub extern "C" fn print_byte(atom: K) -> K{
    ///   match atom.get_byte(){
    ///     Ok(byte) => {
    ///       println!("byte: {:#4x}", byte);
    ///       KNULL
    ///     },
    ///     Err(error) => new_error(error)
    ///   }
    /// }
    /// ```
    /// ```q
    /// q)print_byte: `libapi_examples 2: (`print_byte; 1);
    /// q)print_byte[0xc4]
    /// byte: 0xc4
    /// ```
    fn get_byte(&self) -> Result<u8, &'static str>;

    /// Get an underlying q short.
    /// # Example
    /// ```no_run
    /// use kdbplus::api::*;
    ///
    /// #[no_mangle]
    /// pub extern "C" fn print_short(atom: K) -> K{
    ///   match atom.get_short(){
    ///     Ok(short) => {
    ///       println!("short: {}", short);
    ///       KNULL
    ///     },
    ///     Err(error) => new_error(error)
    ///   }
    /// }
    /// ```
    /// ```q
    /// q)print_short: `libapi_examples 2: (`print_short; 1);
    /// q)print_short[10h]
    /// short: 10
    /// ```
    fn get_short(&self) -> Result<i16, &'static str>;

    /// Get an underlying q int.
    /// # Example
    /// ```no_run
    /// use kdbplus::api::*;
    ///
    /// #[no_mangle]
    /// pub extern "C" fn print_int(atom: K) -> K{
    ///   match atom.get_int(){
    ///     Ok(int) => {
    ///       println!("int: {}", int);
    ///       KNULL
    ///     },
    ///     Err(error) => new_error(error)
    ///   }
    /// }
    /// ```
    /// ```q
    /// q)print_int: `libapi_examples 2: (`print_int; 1);
    /// q)print_int[03:57:20]
    /// int: 14240
    /// ```
    fn get_int(&self) -> Result<i32, &'static str>;

    /// Get an underlying q long.
    /// # Example
    /// ```no_run
    /// use kdbplus::api::*;
    ///
    /// #[no_mangle]
    /// pub extern "C" fn print_long(atom: K) -> K{
    ///   match atom.get_long(){
    ///     Ok(long) => {
    ///       println!("long: {}", long);
    ///       KNULL
    ///     },
    ///     Err(error) => new_error(error)
    ///   }
    /// }
    /// ```
    /// ```q
    /// q)print_long: `libapi_examples 2: (`print_long; 1);
    /// q)print_long[2000.01.01D12:00:00.123456789]
    /// long: 43200123456789
    /// ```
    fn get_long(&self) -> Result<i64, &'static str>;

    /// Get an underlying q real.
    /// # Example
    /// ```no_run
    /// use kdbplus::api::*;
    ///
    /// #[no_mangle]
    /// pub extern "C" fn print_real(atom: K) -> K{
    ///   match atom.get_real(){
    ///     Ok(real) => {
    ///       println!("real: {}", real);
    ///       KNULL
    ///     },
    ///     Err(error) => new_error(error)
    ///   }
    /// }
    /// ```
    /// ```q
    /// q)print_real: `libapi_examples 2: (`print_real; 1);
    /// q)print_real[193810.32e]
    /// real: 193810.31
    /// ```
    fn get_real(&self) -> Result<f32, &'static str>;

    /// Get an underlying q float.
    /// # Example
    /// ```no_run
    /// use kdbplus::api::*;
    ///
    /// #[no_mangle]
    /// pub extern "C" fn print_float(atom: K) -> K{
    ///   match atom.get_float(){
    ///     Ok(float) => {
    ///       println!("float: {:.8}", float);
    ///       KNULL
    ///     },
    ///     Err(error) => new_error(error)
    ///   }
    /// }
    /// ```
    /// ```q
    /// q)print_float: `libapi_examples 2: (`print_float; 1);
    /// q)print_float[2002.01.12T10:03:45.332]
    /// float: 742.41927468
    /// ```
    fn get_float(&self) -> Result<f64, &'static str>;

    /// Get an underlying q char.
    /// # Example
    /// ```no_run
    /// use kdbplus::api::*;
    ///
    /// #[no_mangle]
    /// pub extern "C" fn print_char(atom: K) -> K{
    ///   match atom.get_char(){
    ///     Ok(character) => {
    ///       println!("char: \"{}\"", character);
    ///       KNULL
    ///     },
    ///     Err(error) => new_error(error)
    ///   }
    /// }
    /// ```
    /// ```q
    /// q)print_char: `libapi_examples 2: (`print_char; 1);
    /// q)print_char["k"]
    /// char: "k"
    /// ```
    fn get_char(&self) -> Result<char, &'static str>;

    /// Get an underlying q symbol.
    /// # Example
    /// ```no_run
    /// use kdbplus::api::*;
    ///
    /// #[no_mangle]
    /// pub extern "C" fn print_symbol2(atom: K) -> K{
    ///   match atom.get_symbol(){
    ///     Ok(symbol) => {
    ///       println!("symbol: `{}", symbol);
    ///       KNULL
    ///     },
    ///     Err(error) => new_error(error)
    ///   }
    /// }
    /// ```
    /// ```q
    /// q)print_symbol2: `libapi_examples 2: (`print_symbol2; 1);
    /// q)print_symbol2[`locust]
    /// symbol: `locust
    /// ```
    fn get_symbol(&self) -> Result<&str, &'static str>;

    /// Get an underlying q string as `&str`.
    /// # Example
    /// ```no_run
    /// use kdbplus::api::*;
    ///
    /// #[no_mangle]
    /// pub extern "C" fn print_string(string: K) -> K{
    ///   match string.get_str(){
    ///     Ok(string_) => {
    ///       println!("string: \"{}\"", string_);
    ///       KNULL
    ///     },
    ///     Err(error) => new_error(error)
    ///   }
    /// }
    /// ```
    /// ```q
    /// q)print_string: `libapi_examples 2: (`print_string; 1);
    /// q)print_string["gnat"]
    /// string: "gnat"
    /// ```
    fn get_str(&self) -> Result<&str, &'static str>;

    /// Get an underlying q string as `String`.
    /// # Example
    /// ```no_run
    /// use kdbplus::api::*;
    ///
    /// #[no_mangle]
    /// pub extern "C" fn print_string2(string: K) -> K{
    ///   match string.get_string(){
    ///     Ok(string_) => {
    ///       println!("string: \"{}\"", string_);
    ///       KNULL
    ///     },
    ///     Err(error) => new_error(error)
    ///   }
    /// }
    /// ```
    /// ```q
    /// q)print_string: `libapi_examples 2: (`print_string; 1);
    /// q)print_string["grasshopper"]
    /// string: "grasshopper"
    /// ```
    fn get_string(&self) -> Result<String, &'static str>;

    /// Get a flipped underlying q table as `K` (dictionary).
    /// # Example
    /// ```no_run
    /// use kdbplus::api::*;
    ///
    /// #[no_mangle]
    /// pub extern "C" fn hidden_key(table: K) -> K{
    ///   match table.get_dictionary(){
    ///     Ok(dictionary) => dictionary.as_mut_slice::<K>()[0].q_ipc_encode(3).unwrap(),
    ///     Err(error) => new_error(error)
    ///   }
    /// }
    /// ```
    /// ```q
    /// q)perceive_the_man: `libapi_examples 2: (`hidden_key; 1);
    /// q)perceive_the_man ([] t: `timestamp$.z.p+1e9*til 9; chr:"ljppkgfgs"; is: 7 8 12 14 21 316 400 1000 6000i)
    /// 0x01000000170000000b0003000000740063687200697300
    /// ```
    /// # Note
    /// This method is provided because the ony way to examine the value of table type is to access the underlying dictionary (flipped table).
    ///  Also when some serialization is necessary for a table, you can reuse a serializer for a dictionary if it is already provided. Actually
    ///  when q serialize a table object with `-8!` (q function) or `b9` (C code), it just serializes the underlying dictionary with an additional
    ///  marker indicating a table type.
    fn get_dictionary(&self) -> Result<K, &'static str>;

    /// Get an underlying error symbol as `&str`. This function avoids false positive of processing `KNULL` as an error.
    /// # Example
    /// See the example of [`error_to_string`](fn.error_to_string.html).
    fn get_error_string(&self) -> Result<&str, &'static str>;

    /// Get a table row of the given index. For enumerated column, a names of a target `sym` list
    ///  to which symbol values are cast must be passed. In the example below, it is assumed that
    ///  there is a single enum column in a table and the column values are cast to a symbol list whose name is `sym`.
    /// ```no_run
    /// use kdbplus::api::*;
    /// use kdbplus::qtype;
    ///
    /// #[no_mangle]
    /// pub extern "C" fn print_row(object: K, index: K) -> K{
    ///   match object.get_type(){
    ///     qtype::TABLE => {
    ///       match object.get_row(index.get_long().unwrap() as usize, &["sym"]){
    ///         Ok(row) => {
    ///           let null = unsafe{k(0, str_to_S!("{-1 \"row: \", .Q.s1 x}"), row, KNULL)};
    ///           decrement_reference_count(null);
    ///           KNULL
    ///         }
    ///         Err(error) => new_error(error)
    ///       }
    ///     },
    ///     _ => new_error("not a table\0")
    ///   }
    /// }
    /// ```
    /// ```q
    /// q)row: `libapi_examples 2: (`print_row; 2)
    /// q)table: ([] time: asc `timestamp$.z.p + 3?1000000000; sym: -3?`Green`Yellow`Red; go: "oxx"; miscellaneous: ("cow"; `lion; "eagle"))
    /// q)row[table;2]
    /// row: `time`sym`go`miscellaneous!(2022.01.30D07:55:48.404520689;`Yellow;"x";"eagle")
    /// q)row[table;1]
    /// row: `time`sym`go`miscellaneous!(2022.01.30D07:55:47.987133353;`Green;"x";`lion)
    /// ```
    fn get_row(&self, index: usize, enum_sources: &[&str]) -> Result<K, &'static str>;

    /// Get an attribute of a q object.
    /// # Example
    /// ```no_run
    /// use kdbplus::api::*;
    /// use kdbplus::qattribute;
    ///
    /// #[no_mangle]
    /// pub extern "C" fn murmur(list: K) -> K{
    ///   match list.get_attribute(){
    ///     qattribute::SORTED => {
    ///       new_string("Clean")
    ///     },
    ///     qattribute::UNIQUE => {
    ///       new_symbol("Alone")
    ///     },
    ///     _ => KNULL
    ///   }
    /// }
    /// ```
    fn get_attribute(&self) -> C;

    /// Get a reference count of a q object.
    fn get_refcount(&self) -> I;

    /// Append a q list object to a q list.
    ///  Returns a pointer to the (potentially reallocated) `K` object.
    /// ```no_run
    /// use kdbplus::api::*;
    ///
    /// #[no_mangle]
    /// pub extern "C" fn concat_list2(mut list1: K, list2: K) -> K{
    ///   if let Err(err) = list1.append(increment_reference_count(list2)){
    ///     new_error(err)
    ///   }
    ///   else{
    ///     increment_reference_count(list1)
    ///   }
    /// }
    /// ```
    /// ```q
    /// q)plunder: `libapi_examples 2: (`concat_list2; 2);
    /// q)plunder[(::; `metals; `fire); ("clay"; 316)]
    /// ::
    /// `metals
    /// `fire
    /// "clay"
    /// 316
    /// q)plunder[1 2 3; 4 5]
    /// 1 2 3 4 5
    /// q)plunder[`a`b`c; `d`e]
    /// `a`b`c`d`e
    /// ```
    /// # Note
    /// While native function [`jv`](native/fn.jv.html) does not consume the appended list,
    ///  this function does for intuitiveness. To append externally provided list (i.e., passed
    ///  from q process), apply [`increment_reference_count`](fn.increment_reference_count.html)
    ///  before appending the list.
    fn append(&mut self, list: K) -> Result<K, &'static str>;

    /// Add a q object to a q compound list while the appended one is consumed.
    ///  Returns a pointer to the (potentially reallocated) `K` object.
    /// # Example
    /// ```no_run
    /// use kdbplus::api::*;
    /// use kdbplus::qtype;
    ///
    /// #[no_mangle]
    /// pub extern "C" fn create_compound_list(int: K) -> K{
    ///   let mut list=new_list(qtype::COMPOUND_LIST, 0);
    ///   for i in 0..5{
    ///     list.push(new_long(i)).unwrap();
    ///   }
    ///   list.push(increment_reference_count(int)).unwrap();
    ///   list
    /// }
    /// ```
    /// ```q
    /// q)nums: `libapi_examples 2: (`create_compound_list2; 1);
    /// q)nums[5i]
    /// 0
    /// 1
    /// 2
    /// 3
    /// 4
    /// 5i
    /// ```
    /// # Note
    /// In this example we did not allocate an array as `new_list(qtype::COMPOUND_LIST, 0)` to use `push`.
    ///  As `new_list` initializes the internal list size `n` with its argument, preallocating memory with `new_list` and
    ///  then using `push` will crash. If you want to allocate a memory in advance, you can substitute a value
    ///  after converting the q list object into a slice with [`as_mut_slice`](rait.KUtility.html#tymethod.as_mut_slice).
    fn push(&mut self, atom: K) -> Result<K, &'static str>;

    /// Add a raw value to a q simple list and returns a pointer to the (potentially reallocated) `K` object.
    /// # Example
    /// ```no_run
    /// use kdbplus::api::*;
    /// use kdbplus::qtype;
    ///
    /// #[no_mangle]
    /// pub extern "C" fn create_simple_list2(_: K) -> K{
    ///   let mut list=new_list(qtype::DATE_LIST, 0);
    ///   for i in 0..5{
    ///     list.push_raw(i).unwrap();
    ///   }
    ///   list
    /// }
    /// ```
    /// ```q
    /// q)simple_is_the_best: `lic_api_example 2: (`create_simple_list2; 1);
    /// q)simple_is_the_best[]
    /// 2000.01.01 2000.01.02 2000.01.03 2000.01.04 2000.01.05
    /// ```
    /// # Note
    /// - Concrete type of `T` is not checked. Its type must be either of `I`, `J`, `E` and `F` and it must be compatible
    ///   with the list type. For example, timestamp list requires `J` type atom.
    /// - For symbol list, use [`push_symbol`](#fn.push_symbol) or [`push_symbol_n`](#fn.push_symbol_n).
    fn push_raw<T>(&mut self, atom: T) -> Result<K, &'static str>;

    /// Add a `str` input to a symbol list while enumerating the character array internally.
    ///  Returns a pointer to the (potentially reallocated) `K` object.
    /// # Example
    /// ```no_run
    /// use kdbplus::api::*;
    /// use kdbplus::qtype;
    ///
    /// #[no_mangle]
    /// pub extern "C" fn create_symbol_list2(_: K) -> K{
    ///   let mut list=new_list(qtype::SYMBOL_LIST, 0);
    ///   list.push_symbol("Abraham").unwrap();
    ///   list.push_symbol("Isaac").unwrap();
    ///   list.push_symbol("Jacob").unwrap();
    ///   list.push_symbol_n("Josephine", 6).unwrap();
    ///   list
    /// }
    /// ```
    /// ```q
    /// q)summon:`libapi_examples 2: (`create_symbol_list2; 1)
    /// q)summon[]
    /// `Abraham`Isaac`Jacob`Joseph
    /// q)`Abraham`Isaac`Jacob`Joseph ~ summon[]
    /// 1b
    /// ```
    /// # Note
    /// In this example we did not allocate an array as `new_list(qtype::SYMBOL_LIST as I, 0)` to use `push_symbol`.
    ///  As `new_list` initializes the internal list size `n` with its argument, preallocating memory with `new_list`
    ///  and then using `push_symbol` will crash. If you want to allocate a memory in advance, you can substitute a value
    ///  after converting the q list object into a slice with [`as_mut_slice`](trait.KUtility.html#tymethod.as_mut_slice).
    fn push_symbol(&mut self, symbol: &str) -> Result<K, &'static str>;

    /// Add the first `n` characters of a `str` input to a symbol list while enumerating the character array internally.
    ///  Returns a pointer to the (potentially reallocated) `K` object.
    /// # Example
    /// See the example of [`push_symbol`](#fn.push_symbol).
    fn push_symbol_n(&mut self, symbol: &str, n: I) -> Result<K, &'static str>;

    /// Get the length of q object. The meaning of the returned value varies according to the type:
    /// - atom: 1
    /// - list: The number of elements in the list.
    /// - table: The number of rows.
    /// - dictionary: The number of keys.
    /// - general null: 1
    /// # Example
    /// ```no_run
    /// use kdbplus::api::*;
    ///
    /// #[no_mangle]
    /// pub extern "C" fn numbers(obj: K) -> K{
    ///   let count=format!("{} people are in numbers", obj.len());
    ///   new_string(&count)
    /// }
    /// ```
    /// ```q
    /// q)census: `libapi_examples 2: (`numbers; 1);
    /// q)census[(::)]
    /// "1 people are in numbers"
    /// q)census[til 4]
    /// "4 people are in numbers"
    /// q)census[`a`b!("many"; `split`asunder)]
    /// "2 people are in numbers"
    /// q)census[([] id: til 1000)]
    /// "1000 people are in numbers"
    /// ```
    fn len(&self) -> i64;

    /// Get a type of `K` object.
    fn get_type(&self) -> i8;

    /// Set a type of `K` object.
    /// # Example
    /// See the example of [`load_as_q_function](fn.load_as_q_function.html).
    fn set_type(&mut self, qtype: i8);

    /// Set an attribute to q list object.
    /// # Example
    /// ```no_run
    /// use kdbplus::qattribute;
    /// use kdbplus::api::*;
    ///
    /// #[no_mangle]
    /// pub extern "C" fn labeling(mut list: K) -> K{
    ///   match list.set_attribute(qattribute::SORTED){
    ///     Ok(_) => increment_reference_count(list),
    ///     Err(error) => new_error(error)
    ///   }
    /// }
    /// ```
    /// ```q
    /// q)setter: `libapi_examples.so (`labeling; 1);
    /// q)setter 1 2 3
    /// `s#1 2 3
    /// q)setter 777
    /// 'not a simple list
    /// ```
    /// # Note
    /// q does NOT validate the attribute. Wrong attribute can lead to suboptimal behavior or application crash if
    ///  you are unfortunate.
    fn set_attribute(&mut self, attribute: i8) -> Result<(), &'static str>;

    /// Serialize q object and return serialized q byte list object on success: otherwise null.
    ///  Mode is either of:
    /// - -1: Serialize within the same process.
    /// - 1: retain enumerations, allow serialization of timespan and timestamp: Useful for passing data between threads
    /// - 2: unenumerate, allow serialization of timespan and timestamp
    /// - 3: unenumerate, compress, allow serialization of timespan and timestamp
    /// # Example
    /// ```no_run
    /// use kdbplus::api::*;
    ///
    /// #[no_mangle]
    /// pub extern "C" fn encrypt(object: K)->K{
    ///   match object.q_ipc_encode(3){
    ///     Ok(bytes) => bytes,
    ///     Err(error) => new_error(error)
    ///   }
    /// }
    /// ```
    /// ```q
    /// q)disguise: `libapi_examples 2: (`encrypt; 1);
    /// q)list: (til 3; "abc"; 2018.02.18D04:30:00.000000000; `revive);
    /// q)disguise list
    /// 0x010000004600000000000400000007000300000000000000000000000100000000000000020..
    /// ```
    fn q_ipc_encode(&self, mode: I) -> Result<K, &'static str>;

    /// Deserialize a bytes into q object.
    /// # Example
    /// ```no_run
    /// use kdbplus::api::*;
    ///
    /// #[no_mangle]
    /// pub extern "C" fn decrypt(bytes: K)->K{
    ///   match bytes.q_ipc_decode(){
    ///     Ok(object) => object,
    ///     Err(error) => new_error(error)
    ///   }
    /// }
    /// ```
    /// ```q
    /// q)uncover: `libapi_examples 2: (`decrypt; 1);
    /// q)uncover -8!"What is the purpose of CREATION?"
    /// "What is the purpose of CREATION?"
    /// ```
    fn q_ipc_decode(&self) -> Result<K, &'static str>;
}

//++++++++++++++++++++++++++++++++++++++++++++++++++//
// >> Implementation
//++++++++++++++++++++++++++++++++++++++++++++++++++//

//%% U %%//vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv/

impl U {
    /// Create 16-byte GUID object.
    pub fn new(guid: [u8; 16]) -> Self {
        U { guid }
    }
}

//%% K %%//vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv/

unsafe impl Send for k0_inner {}
unsafe impl Send for k0 {}

impl KUtility for K {
    #[inline]
    fn as_mut_slice<'a, T>(self) -> &'a mut [T] {
        unsafe {
            std::slice::from_raw_parts_mut(
                (*self).value.list.G0.as_mut_ptr() as *mut T,
                (*self).value.list.n as usize,
            )
        }
    }

    fn get_row(&self, index: usize, enum_sources: &[&str]) -> Result<K, &'static str> {
        match unsafe { (**self).qtype } {
            qtype::TABLE => {
                let keys = unsafe { (**self).value.table }.as_mut_slice::<K>()[0];
                let values = unsafe { (**self).value.table }.as_mut_slice::<K>()[1];
                if (unsafe { (*values.as_mut_slice::<K>()[0]).value.list }.n as usize) < index + 1 {
                    // Index out of bounds
                    Err("index out of bounds\0")
                } else {
                    let num_columns = unsafe { (*keys).value.list }.n;
                    let row = new_list(qtype::COMPOUND_LIST, num_columns);
                    let row_slice = row.as_mut_slice::<K>();
                    let mut enum_source_index = 0;
                    for (i, column) in values.as_mut_slice::<K>().iter().enumerate() {
                        match column.get_type() {
                            qtype::BOOL_LIST => {
                                row_slice[i] = new_bool(column.as_mut_slice::<G>()[index] as i32);
                            }
                            qtype::BYTE_LIST => {
                                row_slice[i] = new_byte(column.as_mut_slice::<G>()[index] as i32);
                            }
                            qtype::SHORT_LIST => {
                                row_slice[i] = new_short(column.as_mut_slice::<H>()[index] as i32);
                            }
                            qtype::INT_LIST => {
                                row_slice[i] = new_int(column.as_mut_slice::<I>()[index]);
                            }
                            qtype::LONG_LIST => {
                                row_slice[i] = new_long(column.as_mut_slice::<J>()[index]);
                            }
                            qtype::REAL_LIST => {
                                row_slice[i] = new_real(column.as_mut_slice::<E>()[index] as f64);
                            }
                            qtype::FLOAT_LIST => {
                                row_slice[i] = new_float(column.as_mut_slice::<F>()[index]);
                            }
                            qtype::STRING => {
                                row_slice[i] = new_char(column.as_mut_slice::<G>()[index] as char);
                            }
                            qtype::SYMBOL_LIST => {
                                row_slice[i] =
                                    new_symbol(S_to_str(column.as_mut_slice::<S>()[index]));
                            }
                            qtype::TIMESTAMP_LIST => {
                                row_slice[i] = new_timestamp(column.as_mut_slice::<J>()[index]);
                            }
                            qtype::MONTH_LIST => {
                                row_slice[i] = new_month(column.as_mut_slice::<I>()[index]);
                            }
                            qtype::DATE_LIST => {
                                row_slice[i] = new_date(column.as_mut_slice::<I>()[index]);
                            }
                            qtype::DATETIME_LIST => {
                                row_slice[i] = new_datetime(column.as_mut_slice::<F>()[index]);
                            }
                            qtype::TIMESPAN_LIST => {
                                row_slice[i] = new_timespan(column.as_mut_slice::<J>()[index]);
                            }
                            qtype::MINUTE_LIST => {
                                row_slice[i] = new_minute(column.as_mut_slice::<I>()[index]);
                            }
                            qtype::SECOND_LIST => {
                                row_slice[i] = new_second(column.as_mut_slice::<I>()[index]);
                            }
                            qtype::TIME_LIST => {
                                row_slice[i] = new_time(column.as_mut_slice::<I>()[index]);
                            }
                            qtype::ENUM_LIST => {
                                if enum_sources.len() <= enum_source_index {
                                    // Index out of bounds
                                    decrement_reference_count(row);
                                    return Err("insufficient enum sources\0");
                                }
                                let enum_value = new_enum(
                                    enum_sources[enum_source_index],
                                    column.as_mut_slice::<J>()[index],
                                );
                                if unsafe { (*enum_value).qtype } == qtype::ERROR {
                                    // Error in creating enum object.
                                    decrement_reference_count(row);
                                    let error = S_to_str(unsafe { (*enum_value).value.symbol });
                                    decrement_reference_count(enum_value);
                                    return Err(error);
                                } else {
                                    row_slice[i] = enum_value;
                                    enum_source_index += 1;
                                }
                            }
                            qtype::COMPOUND_LIST => {
                                // Increment reference count since compound list consumes the element.
                                row_slice[i] =
                                    increment_reference_count(column.as_mut_slice::<K>()[index]);
                            }
                            // There are no other list type
                            _ => unreachable!(),
                        }
                    }
                    Ok(new_dictionary(increment_reference_count(keys), row))
                }
            }
            _ => Err("not a table\0"),
        }
    }

    #[inline]
    fn get_bool(&self) -> Result<bool, &'static str> {
        match unsafe { (**self).qtype } {
            qtype::BOOL_ATOM => Ok(unsafe { (**self).value.byte != 0 }),
            _ => Err("not a bool\0"),
        }
    }

    #[inline]
    fn get_guid(&self) -> Result<[u8; 16], &'static str> {
        match unsafe { (**self).qtype } {
            qtype::GUID_ATOM => {
                Ok(
                    unsafe { std::slice::from_raw_parts((**self).value.list.G0.as_ptr(), 16) }
                        .try_into()
                        .unwrap(),
                )
            }
            _ => Err("not a GUID\0"),
        }
    }

    #[inline]
    fn get_byte(&self) -> Result<u8, &'static str> {
        match unsafe { (**self).qtype } {
            qtype::BYTE_ATOM => Ok(unsafe { (**self).value.byte }),
            _ => Err("not a byte\0"),
        }
    }

    #[inline]
    fn get_short(&self) -> Result<i16, &'static str> {
        match unsafe { (**self).qtype } {
            qtype::SHORT_ATOM => Ok(unsafe { (**self).value.short }),
            _ => Err("not a short\0"),
        }
    }

    #[inline]
    fn get_int(&self) -> Result<i32, &'static str> {
        match unsafe { (**self).qtype } {
            qtype::INT_ATOM
            | qtype::MONTH_ATOM
            | qtype::DATE_ATOM
            | qtype::MINUTE_ATOM
            | qtype::SECOND_ATOM
            | qtype::TIME_ATOM => Ok(unsafe { (**self).value.int }),
            _ => Err("not an int\0"),
        }
    }

    #[inline]
    fn get_long(&self) -> Result<i64, &'static str> {
        match unsafe { (**self).qtype } {
            qtype::LONG_ATOM | qtype::TIMESTAMP_ATOM | qtype::TIMESPAN_ATOM | qtype::ENUM_ATOM => {
                Ok(unsafe { (**self).value.long })
            }
            _ => Err("not a long\0"),
        }
    }

    #[inline]
    fn get_real(&self) -> Result<f32, &'static str> {
        match unsafe { (**self).qtype } {
            qtype::REAL_ATOM => Ok(unsafe { (**self).value.real }),
            _ => Err("not a real\0"),
        }
    }

    #[inline]
    fn get_float(&self) -> Result<f64, &'static str> {
        match unsafe { (**self).qtype } {
            qtype::FLOAT_ATOM | qtype::DATETIME_ATOM => Ok(unsafe { (**self).value.float }),
            _ => Err("not a float\0"),
        }
    }

    #[inline]
    fn get_char(&self) -> Result<char, &'static str> {
        match unsafe { (**self).qtype } {
            qtype::CHAR => Ok(unsafe { (**self).value.byte as char }),
            _ => Err("not a char\0"),
        }
    }

    #[inline]
    fn get_symbol(&self) -> Result<&str, &'static str> {
        match unsafe { (**self).qtype } {
            qtype::SYMBOL_ATOM => Ok(S_to_str(unsafe { (**self).value.symbol })),
            _ => Err("not a symbol\0"),
        }
    }

    #[inline]
    fn get_str(&self) -> Result<&str, &'static str> {
        match unsafe { (**self).qtype } {
            qtype::STRING => Ok(unsafe { str::from_utf8_unchecked_mut(self.as_mut_slice::<G>()) }),
            _ => Err("not a string\0"),
        }
    }

    #[inline]
    fn get_string(&self) -> Result<String, &'static str> {
        match unsafe { (**self).qtype } {
            qtype::STRING => {
                Ok(unsafe { String::from_utf8_unchecked(self.as_mut_slice::<G>().to_vec()) })
            }
            _ => Err("not a string\0"),
        }
    }

    #[inline]
    fn get_dictionary(&self) -> Result<K, &'static str> {
        match unsafe { (**self).qtype } {
            qtype::TABLE => Ok(unsafe { (**self).value.table }),
            _ => Err("not a table\0"),
        }
    }

    #[inline]
    fn get_error_string(&self) -> Result<&str, &'static str> {
        match unsafe { (**self).qtype } {
            qtype::ERROR => {
                if !unsafe { (**self).value.symbol }.is_null() {
                    Ok(S_to_str(unsafe { (**self).value.symbol }))
                } else {
                    Err("not an error\0")
                }
            }
            _ => Err("not an error\0"),
        }
    }

    #[inline]
    fn get_attribute(&self) -> i8 {
        unsafe { (**self).attribute }
    }

    #[inline]
    fn get_refcount(&self) -> i32 {
        unsafe { (**self).refcount }
    }

    #[inline]
    fn append(&mut self, list: K) -> Result<K, &'static str> {
        if unsafe { (**self).qtype } >= 0 && unsafe { (**self).qtype } == unsafe { (*list).qtype } {
            let result = Ok(unsafe { native::jv(self, list) });
            // Free appended list for internally created object.
            unsafe { native::r0(list) };
            result
        } else {
            Err("not a list or types do not match\0")
        }
    }

    #[inline]
    fn push(&mut self, atom: K) -> Result<K, &'static str> {
        match unsafe { (**self).qtype } {
            qtype::COMPOUND_LIST => Ok(unsafe { native::jk(self, atom) }),
            _ => Err("not a list or types do not match\0"),
        }
    }

    #[inline]
    fn push_raw<T>(&mut self, mut atom: T) -> Result<K, &'static str> {
        match unsafe { (**self).qtype } {
            _t @ qtype::BOOL_LIST..=qtype::ENUM_LIST => {
                Ok(unsafe { native::ja(self, std::mem::transmute::<*mut T, *mut V>(&mut atom)) })
            }
            _ => Err("not a simple list or types do not match\0"),
        }
    }

    #[inline]
    fn push_symbol(&mut self, symbol: &str) -> Result<K, &'static str> {
        match unsafe { (**self).qtype } {
            qtype::SYMBOL_LIST => Ok(unsafe { native::js(self, native::ss(str_to_S!(symbol))) }),
            _ => Err("not a symbol list\0"),
        }
    }

    #[inline]
    fn push_symbol_n(&mut self, symbol: &str, n: I) -> Result<K, &'static str> {
        match unsafe { (**self).qtype } {
            qtype::SYMBOL_LIST => Ok(unsafe { native::js(self, native::sn(str_to_S!(symbol), n)) }),
            _ => Err("not a symbol list or types do not match\0"),
        }
    }

    #[inline]
    fn len(&self) -> i64 {
        match unsafe { (**self).qtype } {
            _t @ qtype::ENUM_ATOM..=qtype::BOOL_ATOM => {
                // Atom
                1
            }
            _t @ qtype::COMPOUND_LIST..=qtype::ENUM_LIST => {
                // List
                unsafe { (**self).value.list }.n
            }
            qtype::TABLE => {
                // Table
                // Access underlying table (dictionary structure) and retrieve values of the dictionary.
                // The values (columns) is assured to be a list of lists as it is a table. so cast it to list of `K`.
                // Size of the table is a length of the first column.
                unsafe {
                    (*((**self).value.table).as_mut_slice::<K>()[1].as_mut_slice::<K>()[0])
                        .value
                        .list
                }
                .n
            }
            qtype::DICTIONARY | qtype::SORTED_DICTIONARY => {
                // Dictionary
                // Access to keys of the dictionary and retrieve its length.
                unsafe { (*(*self).as_mut_slice::<K>()[0]).value.list }.n
            }
            _ => {
                // General null, function, foreign
                1
            }
        }
    }

    #[inline]
    fn get_type(&self) -> i8 {
        unsafe { (**self).qtype }
    }

    #[inline]
    fn set_type(&mut self, qtype: i8) {
        unsafe { (**self).qtype = qtype };
    }

    #[inline]
    fn set_attribute(&mut self, attribute: i8) -> Result<(), &'static str> {
        match unsafe { (**self).qtype } {
            _t @ qtype::BOOL_LIST..=qtype::TIME_LIST => {
                unsafe { (**self).attribute = attribute };
                Ok(())
            }
            _ => Err("not a simple list\0"),
        }
    }

    #[inline]
    fn q_ipc_encode(&self, mode: I) -> Result<K, &'static str> {
        let result = error_to_string(unsafe { native::b9(mode, *self) });
        match unsafe { (*result).qtype } {
            qtype::ERROR => {
                decrement_reference_count(result);
                Err("failed to encode\0")
            }
            _ => Ok(result),
        }
    }

    #[inline]
    fn q_ipc_decode(&self) -> Result<K, &'static str> {
        match unsafe { (**self).qtype } {
            qtype::BYTE_LIST => {
                let result = error_to_string(unsafe { native::d9(*self) });
                match unsafe { (*result).qtype } {
                    qtype::ERROR => {
                        decrement_reference_count(result);
                        Err("failed to decode\0")
                    }
                    _ => Ok(result),
                }
            }
            _ => Err("not bytes\0"),
        }
    }
}

impl k0 {
    /// Derefer `k0` as a mutable slice. For supported types, see [`as_mut_slice`](trait.KUtility.html#tymethod.as_mut_slice).
    /// # Note
    /// Used if `K` needs to be sent to another thread. `K` cannot implement `Send` and therefore
    ///  its inner struct must be sent instead.
    /// # Example
    /// See the example of [`setm`](native/fn.setm.html).
    #[inline]
    pub fn as_mut_slice<'a, T>(&mut self) -> &'a mut [T] {
        unsafe {
            std::slice::from_raw_parts_mut(
                self.value.list.G0.as_mut_ptr() as *mut T,
                self.value.list.n as usize,
            )
        }
    }
}

//++++++++++++++++++++++++++++++++++++++++++++++++++//
// >> Utility
//++++++++++++++++++++++++++++++++++++++++++++++++++//

//%% Utility %%//vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv/

/// Convert `S` to `&str`. This function is intended to convert symbol type (null-terminated char-array) to `str`.
/// # Extern
/// ```no_run
/// use kdbplus::*;
/// use kdbplus::api::*;
///
/// #[no_mangle]
/// pub extern "C" fn print_symbol(symbol: K) -> K{
///   unsafe{
///     if (*symbol).qtype == qtype::SYMBOL_ATOM{
///       println!("symbol: `{}", S_to_str((*symbol).value.symbol));
///     }
///     // return null
///     KNULL
///   }
/// }
/// ```
/// ```q
/// q)print_symbol:`libapi_examples 2: (`print_symbol; 1)
/// q)a:`kx
/// q)print_symbol a
/// symbol: `kx
/// ```
#[inline]
pub fn S_to_str<'a>(cstring: S) -> &'a str {
    unsafe { CStr::from_ptr(cstring).to_str().unwrap() }
}

/// Convert null-terminated `&str` to `S`.
/// # Example
/// ```no_run
/// use kdbplus::api::*;
///
/// #[no_mangle]
/// pub extern "C" fn pingpong2(_: K) -> K{
///   unsafe{native::k(0, null_terminated_str_to_S("ping\0"), new_int(77), KNULL)}
/// }
/// ```
/// ```q
/// q)ping:{[int] `$string[int], "_pong!!"};
/// q)pingpong: `libapi_examples 2: (`pingpong2; 1);
/// q)pingpong[]
/// `77_pong!!
/// ```
#[inline]
pub fn null_terminated_str_to_S(string: &str) -> S {
    unsafe { CStr::from_bytes_with_nul_unchecked(string.as_bytes()).as_ptr() as S }
}

/// Convert null terminated `&str` into `const_S`. Expected usage is to build
///  a q error object with `krr`.
/// # Example
/// ```no_run
/// use kdbplus::api::*;
/// use kdbplus::api::native::*;
/// use kdbplus::qtype;
///
/// pub extern "C" fn must_be_int2(obj: K) -> K{
///   unsafe{
///     if (*obj).qtype != qtype::INT_ATOM{
///       krr(null_terminated_str_to_const_S("not an int\0"))
///     }
///     else{
///       KNULL
///     }
///   }
/// }
/// ```
/// ```q
/// q)check:`libapi_examples 2: (`must_be_int; 1)
/// q)a:100
/// q)check a
/// 'not an int
///   [0]  check a
///        ^
/// q)a:42i
/// q)check a
/// ```
pub fn null_terminated_str_to_const_S(string: &str) -> const_S {
    string.as_bytes().as_ptr() as const_S
}

//++++++++++++++++++++++++++++++++++++++++++++++++++//
// >> Re-export
//++++++++++++++++++++++++++++++++++++++++++++++++++//

//%% Constructor %%//vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv/

/// Constructor of q bool object. Relabeling of `kb`.
/// # Example
/// ```no_run
/// use kdbplus::api::*;
///
/// #[no_mangle]
/// pub extern "C" fn create_bool(_: K) -> K{
///   new_bool(0)
/// }
/// ```
/// ```q
/// q)no: `libapi_examples 2: (`create_bool; 1);
/// q)no[]
/// 0b
/// ```
#[inline]
pub fn new_bool(boolean: I) -> K {
    unsafe { native::kb(boolean) }
}

/// Constructor of q GUID object. Relabeling of `ku`.
/// # Example
/// ```no_run
/// use kdbplus::api::*;
///
/// #[no_mangle]
/// pub extern "C" fn create_guid(_: K) -> K{
///   new_guid([0x1e_u8, 0x11, 0x17, 0x0c, 0x42, 0x24, 0x25, 0x2c, 0x1c, 0x14, 0x1e, 0x22, 0x4d, 0x3d, 0x46, 0x24])
/// }
/// ```
/// ```q
/// q)create_guid: `libapi_examples 2: (`create_guid; 1);
/// q)create_guid[]
/// 1e11170c-4224-252c-1c14-1e224d3d4624
/// ```
#[inline]
pub fn new_guid(guid: [G; 16]) -> K {
    unsafe { native::ku(U::new(guid)) }
}

/// Constructor of q byte object. Relabeling of `kg`.
/// # Example
/// ```no_run
/// use kdbplus::api::*;
///
/// #[no_mangle]
/// pub extern "C" fn create_byte(_: K) -> K{
///   new_byte(0x3c)
/// }
/// ```
/// ```q
/// q)create_byte: `libapi_examples 2: (`create_byte; 1);
/// q)create_byte[]
/// 0x3c
/// ```
#[inline]
pub fn new_byte(byte: I) -> K {
    unsafe { native::kg(byte) }
}

/// Constructor of q short object. Relabeling of `kh`.
/// # Example
/// ```no_run
/// use kdbplus::api::*;
///
/// #[no_mangle]
/// pub extern "C" fn create_short(_: K) -> K{
///   new_short(-144)
/// }
/// ```
/// ```q
/// q)shortage: `libapi_examples 2: (`create_short; 1);
/// q)shortage[]
/// -144h
/// ```
#[inline]
pub fn new_short(short: I) -> K {
    unsafe { native::kh(short) }
}

/// Constructor of q int object. Relabeling of `ki`.
/// # Example
/// ```no_run
/// use kdbplus::api::*;
///
/// #[no_mangle]
/// pub extern "C" fn create_int(_: K) -> K{
///   new_int(86400000)
/// }
/// ```
/// ```q
/// q)trvial: `libapi_examples 2: (`create_int; 1);
/// q)trivial[]
/// 86400000i
/// ```
#[inline]
pub fn new_int(int: I) -> K {
    unsafe { native::ki(int) }
}

/// Constructor of q long object. Relabeling of `kj`.
/// # Example
/// ```no_run
/// use kdbplus::api::*;
///
/// #[no_mangle]
/// pub extern "C" fn create_long(_: K) -> K{
///   new_long(-668541276001729000)
/// }
/// ```
/// ```q
/// q)lengthy: `libapi_examples 2: (`create_long; 1);
/// q)lengthy[]
/// -668541276001729000
/// ```
#[inline]
pub fn new_long(long: J) -> K {
    unsafe { native::kj(long) }
}

/// Constructor of q real object. Relabeling of `ke`.
/// # Example
/// ```no_run
/// use kdbplus::api::*;
///
/// #[no_mangle]
/// pub extern "C" fn create_real(_: K) -> K{
///   new_real(0.00324)
/// }
/// ```
/// ```q
/// q)reality: `libapi_examples 2: (`create_real; 1);
/// q)reality[]
/// 0.00324e
/// ```
#[inline]
pub fn new_real(real: F) -> K {
    unsafe { native::ke(real) }
}

/// Constructor of q float object. Relabeling of `kf`.
/// # Example
/// ```
/// use kdbplus::api::*;
///
/// #[no_mangle]
/// pub extern "C" fn create_float(_: K) -> K{
///   new_float(-6302.620)
/// }
/// ```
/// ```q
/// q)coffee_float: `libapi_examples 2: (`create_float; 1);
/// q)coffee_float[]
/// -6302.62
/// ```
#[inline]
pub fn new_float(float: F) -> K {
    unsafe { native::kf(float) }
}

///  Constructor of q char object. Relabeling of `kc`.
/// # Example
/// ```no_run
/// use kdbplus::api::*;
///
/// #[no_mangle]
/// pub extern "C" fn create_char2(_: K) -> K{
///   new_char('t')
/// }
/// ```
/// ```q
/// q)heavy: `libapi_examples 2: (`create_char2; 1);
/// q)heavy[]
/// "t"
/// ```
#[inline]
pub fn new_char(character: char) -> K {
    unsafe { native::kc(character as I) }
}

/// Constructor of q symbol object. Relabeling of `ks`.
/// # Example
/// ```no_run
/// use kdbplus::api::*;
///
/// #[no_mangle]
/// pub extern "C" fn create_symbol2(_: K) -> K{
///   new_symbol("symbolic")
/// }
/// ```
/// ```q
/// q)hard: `libapi_examples 2: (`create_symbol2; 1);
/// q)hard[]
/// `symbolic
/// q)`symbolic ~ hard[]
/// 1b
/// ```
#[inline]
pub fn new_symbol(symbol: &str) -> K {
    unsafe { native::ks(str_to_S!(symbol)) }
}

/// Constructor of q timestamp from elapsed time in nanoseconds since kdb+ epoch (`2000.01.01`). Relabeling of `ktj`.
/// ```no_run
/// use kdbplus::api::*;
///
/// #[no_mangle]
/// pub extern "C" fn create_timestamp2(_: K) -> K{
///   // 2015.03.16D00:00:00:00.000000000
///   new_timestamp(479779200000000000)
/// }
/// ```
/// ```q
/// q)stamp: `libapi_examples 2: (`create_timestamp2; 1);
/// q)stamp[]
/// 2015.03.16D00:00:00.000000000
/// ```
#[inline]
pub fn new_timestamp(nanoseconds: J) -> K {
    unsafe { native::ktj(qtype::TIMESTAMP_ATOM as I, nanoseconds) }
}

/// Create a month object from the number of months since kdb+ epoch (`2000.01.01`).
///  This is a complememtal constructor of missing month type.
/// # Example
/// ```no_run
/// use kdbplus::api::*;
///
/// #[no_mangle]
/// pub extern "C" fn create_month(_: K) -> K{
///   // 2010.07m
///   new_month(126)
/// }
/// ```
/// ```q
/// q)create_month: `libapi_examples 2: (`create_month; 1);
/// q)create_month[]
/// 2010.07m
/// ```
#[inline]
pub fn new_month(months: I) -> K {
    unsafe {
        let month = native::ka(qtype::MONTH_ATOM as I);
        (*month).value.int = months;
        month
    }
}

/// Constructor of q date object. Relabeling of `kd`.
/// # Example
/// ```no_run
/// use kdbplus::api::*;
///
/// #[no_mangle]
/// pub extern "C" fn create_date(_: K) -> K{
///   // 1999.12.25
///   new_date(-7)
/// }
/// ```
/// ```q
/// q)nostradamus: `libapi_examples 2: (`create_date; 1);
/// q)nostradamus[]
/// 1999.12.25
/// ```
#[inline]
pub fn new_date(days: I) -> K {
    unsafe { native::kd(days) }
}

/// Constructor of q datetime object from the number of days since kdb+ epoch (`2000.01.01`). Relabeling of `kz`.
/// ```no_run
/// use kdbplus::api::*;
///
/// #[no_mangle]
/// pub extern "C" fn create_datetime(_: K) -> K{
///   // 2015.03.16T12:00:00:00.000
///   new_datetime(5553.5)
/// }
/// ```
/// ```q
/// q)omega_date: libc_api_examples 2: (`create_datetime; 1);
/// q)omega_date[]
/// 2015.03.16T12:00:00.000
/// ```
#[inline]
pub fn new_datetime(days: F) -> K {
    unsafe { native::kz(days) }
}

/// Constructor of q timespan object from nanoseconds. Relabeling of `ktj`.
/// ```no_run
/// use kdbplus::api::*;
///
/// #[no_mangle]
/// pub extern "C" fn create_timespan2(_: K) -> K{
///   // -1D01:30:00.001234567
///   new_timespan(-91800001234567)
/// }
/// ```
/// ```q
/// q)duration: libc_api_examples 2: (`create_timespan2; 1);
/// q)duration[]
/// -1D01:30:00.001234567
/// ```
#[inline]
pub fn new_timespan(nanoseconds: J) -> K {
    unsafe { native::ktj(qtype::TIMESPAN_ATOM as I, nanoseconds) }
}

/// Create a month object. This is a complememtal constructor of
///  missing minute type.
/// # Example
/// ```no_run
/// use kdbplus::api::*;
///
/// #[no_mangle]
/// pub extern "C" fn create_minute(_: K) -> K{
///   // 10:40
///   new_minute(640)
/// }
/// ```
/// ```q
/// q)minty: `libapi_examples 2: (`create_minute; 1);
/// q)minty[]
/// 10:40
/// ```
#[inline]
pub fn new_minute(minutes: I) -> K {
    unsafe {
        let minute = native::ka(qtype::MINUTE_ATOM as I);
        (*minute).value.int = minutes;
        minute
    }
}

/// Create a month object. This is a complememtal constructor of
///  missing second type.
/// # Example
/// ```no_run
/// use kdbplus::api::*;
///
/// #[no_mangle]
/// pub extern "C" fn create_second(_: K) -> K{
///   // -02:00:00
///   new_second(-7200)
/// }
/// ```
/// ```q
/// q)third: `libapi_examples 2: (`create_second; 1);
/// q)third[]
/// -02:00:00
/// ```
#[inline]
pub fn new_second(seconds: I) -> K {
    unsafe {
        let second = native::ka(qtype::SECOND_ATOM as I);
        (*second).value.int = seconds;
        second
    }
}

/// Constructor of q time object. Relabeling of `kt`.
/// # Example
/// ```no_run
/// use kdbplus::api::*;
///
/// #[no_mangle]
/// pub extern "C" fn create_time(_: K) -> K{
///   // -01:30:00.123
///   new_time(-5400123)
/// }
/// ```
/// ```q
/// q)ancient: libc_api_examples 2: (`create_time; 1);
/// q)ancient[]
/// -01:30:00.123
/// ```
#[inline]
pub fn new_time(milliseconds: I) -> K {
    unsafe { native::kt(milliseconds) }
}

/// Constructor of q enum object. This is a complememtal constructor of
///  missing second type.
/// # Example
/// ```no_run
/// use kdbplus::api::*;
///
/// #[no_mangle]
/// pub extern "C" fn create_enum(source: K, index: K) -> K{
///   // Error if the specified enum source does not exist or it is not a symbol list or the index is out of enum range
///   new_enum(source.get_str().unwrap(), index.get_long().unwrap())
/// }
/// ```
/// ```q
/// q)enumerate: libc_api_examples 2: (`create_enum; 2);
/// q)sym: `a`b`c
/// q)enumerate["sym"; 1]
/// `sym$`b
/// q)enumerate["sym"; 3]
/// 'index out of enum range
///   [0]  enumerate["sym"; 3]
///        ^
/// q)enumerate["som"; 0]
/// 'som
/// [1]  som
///      ^
/// q))\
/// q)som:til 3
/// q)enumerate["som"; 0]
/// 'enum must be cast to symbol list
///   [0]  enumerate["som"; 0]
///        ^
/// q)som:`a`b
/// q)enumerate["som"; 0]
/// `som$`a
/// ```
#[inline]
pub fn new_enum(source: &str, index: J) -> K {
    let sym = unsafe { native::k(0, str_to_S!(source), KNULL) };
    if unsafe { (*sym).qtype } == qtype::ERROR {
        // Error. Specified sym does not exist
        sym
    } else if unsafe { (*sym).qtype } != qtype::SYMBOL_LIST {
        // sym is not a symbol list
        unsafe {
            native::r0(sym);
            native::krr(null_terminated_str_to_const_S(
                "enum must be cast to symbol list\0",
            ))
        }
    } else if unsafe { (*sym).value.list.n } <= index {
        // Index is out of sym range
        unsafe {
            native::r0(sym);
            native::krr(null_terminated_str_to_const_S("index out of enum range\0"))
        }
    } else {
        let function = format!("{{`{}${} x}}", source, source);
        unsafe {
            native::r0(sym);
            native::k(0, str_to_S!(function.as_str()), native::kj(index), KNULL)
        }
    }
}

/// Constructor of q simple list.
/// # Example
/// See the example of [`new_dictionary`](fn.new_dictionary.html).
#[inline]
pub fn new_list(qtype: i8, length: J) -> K {
    unsafe { native::ktn(qtype as I, length) }
}

/// Constructor of q string object.
/// # Example
/// ```no_run
/// use kdbplus::api::*;
///
/// #[no_mangle]
/// pub extern "C" fn create_string(_: K) -> K{
///   new_string("this is a text.")
/// }
/// ```
/// ```q
/// q)text: libc_api_examples 2: (`create_string; 1);
/// q)text[]
/// "this is a text."
/// ```
#[inline]
pub fn new_string(string: &str) -> K {
    unsafe { native::kp(str_to_S!(string)) }
}

/// Constructor if q string object with a fixed length.
/// # Example
/// ```no_run
/// use kdbplus::api::*;
///
/// #[no_mangle]
/// pub extern "C" fn create_string2(_: K) -> K{
///   new_string_n("The meeting was too long and I felt it s...", 24)
/// }
/// ```
/// ```q
/// q)speak_inwardly: libc_api_examples 2: (`create_string2; 1);
/// q)speak_inwardly[]
/// "The meeting was too long"
/// ```
#[inline]
pub fn new_string_n(string: &str, length: J) -> K {
    unsafe { native::kpn(str_to_S!(string), length) }
}

/// Constructor of q dictionary object.
/// # Example
/// ```no_run
/// use kdbplus::api::*;
/// use kdbplus::qtype;
///
/// #[no_mangle]
/// pub extern "C" fn create_dictionary() -> K{
///   let keys=new_list(qtype::INT_LIST, 2);
///   keys.as_mut_slice::<I>()[0..2].copy_from_slice(&[0, 1]);
///   let values=new_list(qtype::COMPOUND_LIST, 2);
///   let date_list=new_list(qtype::DATE_LIST, 3);
///   // 2000.01.01 2000.01.02 2000.01.03
///   date_list.as_mut_slice::<I>()[0..3].copy_from_slice(&[0, 1, 2]);
///   let string=new_string("I'm afraid I would crash the application...");
///   values.as_mut_slice::<K>()[0..2].copy_from_slice(&[date_list, string]);
///   new_dictionary(keys, values)
/// }
/// ```
/// ```q
/// q)create_dictionary: `libapi_examples 2: (`create_dictionary; 1);
/// q)create_dictionary[]
/// 0| 2000.01.01 2000.01.02 2000.01.03
/// 1| "I'm afraid I would crash the application..."
/// ```
#[inline]
pub fn new_dictionary(keys: K, values: K) -> K {
    unsafe { native::xD(keys, values) }
}

/// Constructor of q general null.
/// # Example
/// ```no_run
/// use kdbplus::qtype;
/// use kdbplus::api::*;
///
/// #[no_mangle]
/// pub extern "C" fn nullify(_: K) -> K{
///   let nulls=new_list(qtype::COMPOUND_LIST, 3);
///   let null_slice=nulls.as_mut_slice::<K>();
///   null_slice[0]=new_null();
///   null_slice[1]=new_string("null is not a general null");
///   null_slice[2]=new_null();
///   nulls
/// }
/// ```
/// ```q
/// q)void: `libapi_examples 2: (`nullify; 1);
/// q)void[]
/// ::
/// "null is not a general null"
/// ::
/// ```
#[inline]
pub fn new_null() -> K {
    unsafe {
        let null = native::ka(qtype::NULL as I);
        (*null).value.byte = 0;
        null
    }
}

/// Constructor of q error. The input must be null-terminated.
/// # Example
/// ```no_run
/// use kdbplus::api::*;
///
/// pub extern "C" fn thai_kick(_: K) -> K{
///   new_error("Thai kick unconditionally!!\0")
/// }
/// ```
/// ```q
/// q)monstrous: `libapi_examples 2: (`thai_kick; 1);
/// q)monstrous[]
/// 'Thai kick unconditionally!!
/// [0]  monstrous[]
///      ^
/// ```
#[inline]
pub fn new_error(message: &str) -> K {
    unsafe { native::krr(null_terminated_str_to_const_S(message)) }
}

/// Similar to `new_error` but this function appends a system-error message to string `S` before passing it to internal `krr`.
///  The input must be null-terminated.
#[inline]
pub fn new_error_os(message: &str) -> K {
    unsafe { native::orr(null_terminated_str_to_const_S(message)) }
}

/// Convert an error object into usual `K` object which has the error string in the field `symbol`.
/// # Example
/// ```no_run
/// use kdbplus::*;
/// use kdbplus::api::*;
///
/// extern "C" fn no_panick(func: K, args: K) -> K{
///   let result=error_to_string(apply(func, args));
///   if let Ok(error) = result.get_error_string(){
///     println!("FYI: {}", error);
///     // Decrement reference count of the error object which is no longer used.
///     decrement_reference_count(result);
///     KNULL
///   }
///   else{
///     result
///   }
/// }
/// ```
/// ```q
/// q)chill: `libapi_examples 2: (`no_panick; 2);
/// q)chill[$; ("J"; "42")]
/// success!
/// 42
/// q)chill[+; (1; `a)]
/// FYI: type
/// ```
/// # Note
/// If you intend to use the error string only in Rust side and not to return the value, you need
///  to decrement the reference count of the error object created by `error_to_string` as shown above.
///  If you want to propagate the error to q side after some operation, you can just return it (See the
///  example of [`is_error`](fn.is_error.html)).
///
/// # Warning
/// In q, an error is a 0 pointer. This causes a problem of false positive by `error_to_string`, i.e.,
///  `KNULL` is also catched as an error object and its type is set `qtype::ERROR`. In such a case you must NOT
///  return the catched object because it causes segmentation fault. If you want to check if the catched object
///  is an error and then return if it is, you should use [`is_error`](fn.is_error.html). If you want to use the
///  underlying error string of the catched object, you should use [`get_error_string`](trait.KUtility.html#tymethod.get_error_string).
#[inline]
pub fn error_to_string(error: K) -> K {
    unsafe { native::ee(error) }
}

/// Judge if a catched object by [`error_to_string`](fn.error_to_string.html) is a genuine error object of type
///  `qtype::ERROR` (This means false positive of the `KNULL` case can be eliminated).
/// # Examples
/// ```no_run
/// use kdbplus::*;
/// use kdbplus::api::*;
///
/// fn love_even(arg: K) -> K{
///   if let Ok(int) = arg.get_int(){
///     if int % 2 == 0{
///       // Silent for even value
///       KNULL
///     }
///     else{
///       // Shout against odd value
///       new_error("great is the even value!!\0")
///     }
///   }
///   else{
///     // Pass through
///     increment_reference_count(arg)
///   }
/// }
///
/// #[no_mangle]
/// pub extern "C" fn propagate(arg: K) -> K{
///   let result=error_to_string(love_even(arg));
///   if is_error(result){
///     // Propagate the error
///     result
///   }
///   else if result.get_type() == qtype::ERROR{
///     // KNULL
///     println!("this is KNULL");
///     decrement_reference_count(result);
///     KNULL
///   }
///   else{
///     // Other
///     new_symbol("sonomama")
///   }
/// }
/// ```
/// ```q
/// q)convey: `libapi_examples 2: (`propagate; 1);
/// q)convey[7i]
/// 'great is the even value!!
/// q)convey[12i]
/// this is KNULL
/// q)convey[5.5]
/// `sonomama
/// ```
/// # Note
/// In this example `KNULL` is used as a returned value of the function called by another function to demonstrate
///  how `is_error` works. However, `KNULL` should not be used in such a way in order to avoid this kind of complexity.
///  To return a general null for inner functions, use [`new_null`](fn.new_null.html) instead.
#[inline]
pub fn is_error(catched: K) -> bool {
    (unsafe { (*catched).qtype } == qtype::ERROR) && !unsafe { (*catched).value.symbol }.is_null()
}

//%% Symbol %%//vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv/

/// Extract the first `n` chars from a character array and enumerate it internally.
///  This function must be used to add a character array as a symbol value to a symbol list.
///  The returned value is the same character array as the input.
/// # Example
/// See the example of [`flip`](fn.flip.html).
/// # Note
/// The reason why this function must be used is to enumerate the character array before handling
///  it as a q symbol type value. q/kdb+ is enumerating all symbol values to optimize comparison
///  or memory usage. On the other hand [`new_symbol`] does the enumeration internally and
///  therefore it does not need this function.
#[inline]
pub fn enumerate_n(string: S, n: I) -> S {
    unsafe { native::sn(string, n) }
}

/// Enumerate a null-terminated character array internally. This function must be used
///  to add a character array as a symbol value to a symbol list. The returned value is
///  the same character array as the input.
/// # Example
/// See the example of [`flip`](fn.flip.html).
/// # Note
/// The reason why this function must be used is to enumerate the character array before handling
///  it as a q symbol type value. q/kdb+ is enumerating all symbol values to optimize comparison
///  or memory usage. On the other hand [`new_symbol`] does the enumeration internally and
///  therefore it does not need this function.
#[inline]
pub fn enumerate(string: S) -> S {
    unsafe { native::ss(string) }
}

//%% Table %%//vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv/

/// Constructor of q table object from a q dictionary object.
/// # Note
/// Basically this is a `flip` command of q. Hence the value of the dictionary must have
///  lists as its elements.
/// ```no_run
/// #[macro_use]
/// extern crate kdbplus;
/// use kdbplus::api::*;
/// use kdbplus::qtype;
///
/// #[no_mangle]
/// pub extern "C" fn create_table2(_: K) -> K{
///   // Build keys
///   let keys=new_list(qtype::SYMBOL_LIST, 2);
///   let keys_slice=keys.as_mut_slice::<S>();
///   keys_slice[0]=enumerate(str_to_S!("time"));
///   keys_slice[1]=enumerate_n(str_to_S!("temperature_and_humidity"), 11);
///   
///   // Build values
///   let values=new_list(qtype::COMPOUND_LIST, 2);
///   let time=new_list(qtype::TIMESTAMP_LIST, 3);
///   // 2003.10.10D02:24:19.167018272 2006.05.24D06:16:49.419710368 2008.08.12D23:12:24.018691392
///   time.as_mut_slice::<J>().copy_from_slice(&[119067859167018272_i64, 201766609419710368, 271897944018691392]);
///   let temperature=new_list(qtype::FLOAT_LIST, 3);
///   temperature.as_mut_slice::<F>().copy_from_slice(&[22.1_f64, 24.7, 30.5]);
///   values.as_mut_slice::<K>().copy_from_slice(&[time, temperature]);
///   
///   flip(new_dictionary(keys, values))
/// }
/// ```
/// ```q
/// q)climate_change: libc_api_examples 2: (`create_table2; 1);
/// q)climate_change[]
/// time                          temperature
/// -----------------------------------------
/// 2003.10.10D02:24:19.167018272 22.1       
/// 2006.05.24D06:16:49.419710368 24.7       
/// 2008.08.12D23:12:24.018691392 30.5    
/// ```
#[inline]
pub fn flip(dictionary: K) -> K {
    match unsafe { (*dictionary).qtype } {
        qtype::DICTIONARY => unsafe { native::xT(dictionary) },
        _ => unsafe { native::krr(null_terminated_str_to_const_S("not a dictionary\0")) },
    }
}

/// Constructor of simple q table object from a q keyed table object.
/// # Example
/// ```no_run
/// #[macro_use]
/// extern crate kdbplus;
/// use kdbplus::api::*;
/// use kdbplus::qtype;
///
/// #[no_mangle]
/// pub extern "C" fn create_table2(_: K) -> K{
///   // Build keys
///   let keys=new_list(qtype::SYMBOL_LIST, 2);
///   let keys_slice=keys.as_mut_slice::<S>();
///   keys_slice[0]=enumerate(str_to_S!("time"));
///   keys_slice[1]=enumerate_n(str_to_S!("temperature_and_humidity"), 11);
///   
///   // Build values
///   let values=new_list(qtype::COMPOUND_LIST, 2);
///   let time=new_list(qtype::TIMESTAMP_LIST, 3);
///   // 2003.10.10D02:24:19.167018272 2006.05.24D06:16:49.419710368 2008.08.12D23:12:24.018691392
///   time.as_mut_slice::<J>().copy_from_slice(&[119067859167018272_i64, 201766609419710368, 271897944018691392]);
///   let temperature=new_list(qtype::FLOAT_LIST, 3);
///   temperature.as_mut_slice::<F>().copy_from_slice(&[22.1_f64, 24.7, 30.5]);
///   values.as_mut_slice::<K>().copy_from_slice(&[time, temperature]);
///   
///   flip(new_dictionary(keys, values))
/// }
///
/// #[no_mangle]
/// pub extern "C" fn create_keyed_table(dummy: K) -> K{
///   enkey(create_table2(dummy), 1)
/// }
///
/// #[no_mangle]
/// pub extern "C" fn keyed_to_simple_table(dummy: K) -> K{
///   unkey(create_keyed_table(dummy))
/// }
/// ```
/// ```q
/// q)unkey: libc_api_examples 2: (`keyed_to_simple_table; 1);
/// q)unkey[]
/// time                          temperature
/// -----------------------------------------
/// 2003.10.10D02:24:19.167018272 22.1       
/// 2006.05.24D06:16:49.419710368 24.7       
/// 2008.08.12D23:12:24.018691392 30.5    
/// ```
#[inline]
pub fn unkey(keyed_table: K) -> K {
    match unsafe { (*keyed_table).qtype } {
        qtype::DICTIONARY => unsafe { native::ktd(keyed_table) },
        _ => unsafe { native::krr(null_terminated_str_to_const_S("not a keyed table\0")) },
    }
}

/// Constructor of q keyed table object.
/// # Parameters
/// - `table`: q table object to be enkeyed.
/// - `n`: The number of key columns from the left.
/// # Example
/// ```no_run
/// #[macro_use]
/// extern crate kdbplus;
/// use kdbplus::api::*;
/// use kdbplus::qtype;
///
/// #[no_mangle]
/// pub extern "C" fn create_table2(_: K) -> K{
///   // Build keys
///   let keys=new_list(qtype::SYMBOL_LIST, 2);
///   let keys_slice=keys.as_mut_slice::<S>();
///   keys_slice[0]=enumerate(str_to_S!("time"));
///   keys_slice[1]=enumerate_n(str_to_S!("temperature_and_humidity"), 11);
///   
///   // Build values
///   let values=new_list(qtype::COMPOUND_LIST, 2);
///   let time=new_list(qtype::TIMESTAMP_LIST, 3);
///   // 2003.10.10D02:24:19.167018272 2006.05.24D06:16:49.419710368 2008.08.12D23:12:24.018691392
///   time.as_mut_slice::<J>().copy_from_slice(&[119067859167018272_i64, 201766609419710368, 271897944018691392]);
///   let temperature=new_list(qtype::FLOAT_LIST, 3);
///   temperature.as_mut_slice::<F>().copy_from_slice(&[22.1_f64, 24.7, 30.5]);
///   values.as_mut_slice::<K>().copy_from_slice(&[time, temperature]);
///   
///   flip(new_dictionary(keys, values))
/// }
///
/// #[no_mangle]
/// pub extern "C" fn create_keyed_table(dummy: K) -> K{
///   enkey(create_table2(dummy), 1)
/// }
/// ```
/// ```q
/// q)locker: libc_api_examples 2: (`create_keyed_table; 1);
/// q)locker[]
/// time                         | temperature
/// -----------------------------| -----------
/// 2003.10.10D02:24:19.167018272| 22.1       
/// 2006.05.24D06:16:49.419710368| 24.7       
/// 2008.08.12D23:12:24.018691392| 30.5  
/// ```
#[inline]
pub fn enkey(table: K, n: J) -> K {
    match unsafe { (*table).qtype } {
        qtype::TABLE => unsafe { native::knt(n, table) },
        _ => unsafe { native::krr(null_terminated_str_to_const_S("not a table\0")) },
    }
}

//%% Reference Count %%//vvvvvvvvvvvvvvvvvvvvvvvvvvvv/

/// Decrement reference count of the q object. The decrement must be done when `k` function gets an error
///  object whose type is `qtype::ERROR` and when you created an object but do not intend to return it to
///  q side. See details on [the reference page](https://code.kx.com/q/interfaces/c-client-for-q/#managing-memory-and-reference-counting).
/// # Example
/// ```no_run
/// use kdbplus::api::*;
///
/// #[no_mangle]
/// pub extern "C" fn agriculture(_: K)->K{
///   // Produce an apple.
///   let fruit=new_symbol("apple");
///   // Sow the apple seed.
///   decrement_reference_count(fruit);
///   // Return null.
///   KNULL
/// }
/// ```
/// ```q
/// q)do_something: `libapi_examples 2: (`agriculture; 1);
/// q)do_something[]
/// q)
/// ```
#[inline]
pub fn decrement_reference_count(qobject: K) -> V {
    unsafe { native::r0(qobject) }
}

/// Increment reference count of the q object. Increment must be done when you passed arguments
///  to Rust function and intends to return it to q side or when you pass some `K` objects to `k`
///  function and intend to use the argument after the call.
///  See details on [the reference page](https://code.kx.com/q/interfaces/c-client-for-q/#managing-memory-and-reference-counting).
/// # Example
/// ```no_run
/// #[macro_use]
/// extern crate kdbplus;
/// use kdbplus::api::*;
///
/// fn eat(apple: K){
///   println!("おいしい！");
/// }
///
/// #[no_mangle]
/// pub extern "C" fn satisfy_5000_men(apple: K) -> K{
///   for _ in 0..10{
///     eat(apple);
///   }
///   unsafe{native::k(0, str_to_S!("eat"), increment_reference_count(apple), KNULL);}
///   increment_reference_count(apple)  
/// }
/// ```
/// ```q
/// q)eat:{[apple] show "Collect the clutter of apples!";}
/// q)bread_is_a_sermon: libc_api_examples 2: (`satisfy_5000_men; 1);
/// q)bread_is_a_sermon[`green_apple]
/// おいしい！
/// おいしい！
/// おいしい！
/// おいしい！
/// おいしい！
/// おいしい！
/// おいしい！
/// おいしい！
/// おいしい！
/// おいしい！
/// "Collect the clutter of apples!"
/// ```
#[inline]
pub fn increment_reference_count(qobject: K) -> K {
    unsafe { native::r1(qobject) }
}

//%% Callback %%//vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv/

/// Remove callback from the associated kdb+ socket and call `kclose`.
///  Return null if the socket is invalid or not the one which had been registered by `sd1`.
/// # Note
/// A function which calls this function must be executed at the exit of the process.
#[inline]
pub fn destroy_socket(socket: I) {
    unsafe {
        native::sd0(socket);
    }
}

/// Remove callback from the associated kdb+ socket and call `kclose` if the given condition is satisfied.
///  Return null if the socket is invalid or not the one which had been registered by `sd1`.
/// # Note
/// A function which calls this function must be executed at the exit of the process.
#[inline]
pub fn destroy_socket_if(socket: I, condition: bool) {
    unsafe {
        native::sd0x(socket, condition as I);
    }
}

/// Register callback to the associated kdb+ socket.
/// ```no_run
/// #[macro_use]
/// extern crate kdbplus;
/// use kdbplus::api::*;
/// use kdbplus::qtype;
///
/// static mut PIPE:[I; 2]=[-1, -1];
///
/// // Callback for some message queue.
/// extern "C" fn callback(socket: I)->K{
///   let mut buffer: [K; 1]=[0 as K];
///   unsafe{libc::read(socket, buffer.as_mut_ptr() as *mut V, 8)};
///   // Call `shout` function on q side with the received data.
///   let result=error_to_string(unsafe{native::k(0, str_to_S!("shout"), buffer[0], KNULL)});
///   if result.get_type() == qtype::ERROR{
///     eprintln!("Execution error: {}", result.get_symbol().unwrap());
///     decrement_reference_count(result);
///   };
///   KNULL
/// }
///
/// #[no_mangle]
/// pub extern "C" fn plumber(_: K) -> K{
///   if 0 != unsafe{libc::pipe(PIPE.as_mut_ptr())}{
///     return new_error("Failed to create pipe\0");
///   }
///   if KNULL == register_callback(unsafe{PIPE[0]}, callback){
///     return new_error("Failed to register callback\0");
///   }
///   // Lock symbol in a worker thread.
///   pin_symbol();
///   let handle=std::thread::spawn(move ||{
///     let mut precious=new_list(qtype::SYMBOL_LIST, 3);
///     let precious_array=precious.as_mut_slice::<S>();
///     precious_array[0]=enumerate(null_terminated_str_to_S("belief\0"));
///     precious_array[1]=enumerate(null_terminated_str_to_S("love\0"));
///     precious_array[2]=enumerate(null_terminated_str_to_S("hope\0"));
///     unsafe{libc::write(PIPE[1], std::mem::transmute::<*mut K, *mut V>(&mut precious), 8)};
///   });
///   handle.join().unwrap();
///   unpin_symbol();
///   KNULL
/// }
/// ```
/// ```q
/// q)shout:{[precious] -1 "What are the three largest elements?: ", .Q.s1 precious;};
/// q)fall_into_pipe: `libc_api_example 2: (`plumber; 1);
/// q)fall_into_pipe[]
/// What are the three largest elements?: `belief`love`hope
/// ```
#[inline]
pub fn register_callback(socket: I, function: extern "C" fn(I) -> K) -> K {
    unsafe { native::sd1(socket, function) }
}

//%% Miscellaneous %%//vvvvvvvvvvvvvvvvvvvvvvvvvvvvvv/

/// Apply a function to q list object `.[func; args]`.
/// # Example
/// See the example of [`error_to_string`](fn.error_to_string.html).
#[inline]
pub fn apply(func: K, args: K) -> K {
    unsafe { native::dot(func, args) }
}

/// Enable the remote threads to refer to the sym list in the main thread so that enumeration
///  of remotely created symbol values reain valid in the main thread after joining the
///  remote threads. This function must be used before starting any other threads if the
///  threads create symbol values. The previously set value is returned.
/// # Example
/// See the example of [`register_callback`](fn.register_callback.html).
#[inline]
pub fn pin_symbol() -> I {
    unsafe { native::setm(1) }
}

/// Unlock the symbol list in the main thread. This function should be called after joining
///  threads.
/// # Example
/// See the example of [`register_callback`](fn.register_callback.html).
#[inline]
pub fn unpin_symbol() -> I {
    unsafe { native::setm(0) }
}

/// Drop Rust object inside q. Passed as the first element of a foreign object.
/// # Parameters
/// - `obj`: List of (function to free the object; foreign object).
/// # Example
/// See the example of [`load_as_q_function`](fn.load_as_q_function.html).
pub fn drop_q_object(obj: K) -> K {
    let obj_slice = obj.as_mut_slice::<K>();
    // Take ownership of `K` object from a raw pointer and drop at the end of this scope.
    unsafe {
        let _ = Box::from_raw(obj_slice[1]);
    };
    // Fill the list with null.
    obj_slice.copy_from_slice(&[KNULL, KNULL]);
    obj
}

/// Load C function as a q function (`K` object).
/// # Parameters
/// - `func`: A function takes a C function that would take `n` `K` objects as arguments and returns a `K` object.
/// - `n`: The number of arguments for the function.
/// # Example
/// ```no_run
/// #[macro_use]
/// extern crate kdbplus;
/// use kdbplus::api::*;
/// use kdbplus::qtype;
///
/// #[derive(Clone, Debug)]
/// struct Planet{
///   name: String,
///   population: i64,
///   water: bool
/// }
///
/// impl Planet{
///   /// Constructor of `Planet`.
///   fn new(name: &str, population: i64, water: bool) -> Self{
///     Planet{
///       name: name.to_string(),
///       population: population,
///       water: water
///     }
///   }
///
///   /// Description of the planet.
///   fn description(&self)->String{
///     let mut desc=format!("The planet {} is a beautiful planet where {} people reside.", self.name, self.population);
///     if self.water{
///       desc+=" Furthermore water is flowing on the surface of it.";
///     }
///     desc
///   }
/// }
///
/// /// Example of `set_type`.
/// #[no_mangle]
/// pub extern "C" fn eden(_: K) -> K{
///   let earth=Planet::new("earth", 7500_000_000, true);
///   let mut foreign=new_list(qtype::COMPOUND_LIST, 2);
///   let foreign_slice=foreign.as_mut_slice::<K>();
///   foreign_slice[0]=drop_q_object as K;
///   foreign_slice[1]=Box::into_raw(Box::new(earth)) as K;
///   // Set as foreign object.
///   foreign.set_type(qtype::FOREIGN);
///   foreign
/// }
///
/// extern "C" fn invade(planet: K, action: K) -> K{
///   let obj=planet.as_mut_slice::<K>()[1] as *const Planet;
///   println!("{:?}", unsafe{obj.as_ref()}.unwrap());
///   let mut desc=unsafe{obj.as_ref()}.unwrap().description();
///   if action.get_bool().unwrap(){
///     desc+=" You shall not curse what God blessed.";
///   }
///   else{
///     desc+=" I perceived I could find favor of God by blessing them.";
///   }
///   new_string(&desc)
/// }
///
/// /// Example of `load_as_q_function`.
/// #[no_mangle]
/// pub extern "C" fn probe(planet: K)->K{
///   // Return monadic function
///   unsafe{native::k(0, str_to_S!("{[func; planet] func[planet]}"), load_as_q_function(invade as *const V, 2), planet, KNULL)}
/// }
/// ```
/// ```q
/// q)eden: libc_api_example 2: (`eden; 1);
/// q)earth: eden[]
/// q)type earth
/// 112h
/// q)probe: libc_api_example 2: (`probe; 1);
/// q)invade: probe[earth];
/// q)\c 25 200
/// q)invade 1b
/// "The planet earth is a beautiful planet where 7500000000 people reside. Furthermore water is flowing on the surface of it. You shall not curse what God blessed."
/// ```
#[inline]
pub fn load_as_q_function(func: *const V, n: J) -> K {
    unsafe { native::dl(func, n) }
}

/// Convert ymd to the number of days from `2000.01.01`.
/// # Example
/// ```no_run
/// use kdbplus::api::*;
///
/// let days=ymd_to_days(2020, 4, 1);
/// assert_eq!(days, 7396);
/// ```
#[inline]
pub fn ymd_to_days(year: I, month: I, date: I) -> I {
    unsafe { native::ymd(year, month, date) }
}

/// Convert the number of days from `2000.01.01` to a number expressed as `yyyymmdd`.
/// # Example
/// ```no_run
/// use kdbplus::api::*;
///
/// let number=days_to_ymd(7396);
/// assert_eq!(number, 20200401);
/// ```
#[inline]
pub fn days_to_ymd(days: I) -> I {
    unsafe { native::dj(days) }
}

/// Convert a simple list to a compound list. Expected usage is to concatinate a simple list
///  with a different type of list.
/// # Example
/// ```no_run
/// use kdbplus::*;
/// use kdbplus::api::*;
///
/// #[no_mangle]
/// pub extern "C" fn drift(_: K)->K{
///   let simple=new_list(qtype::INT_LIST, 2);
///   simple.as_mut_slice::<I>().copy_from_slice(&[12, 34]);
///   let extra=new_list(qtype::COMPOUND_LIST, 2);
///   extra.as_mut_slice::<K>().copy_from_slice(&[new_symbol("vague"), new_int(-3000)]);
///   // Convert an integer list into a compound list
///   let mut compound = simple_to_compound(simple, "");
///   compound.append(extra).unwrap()
/// }
///
/// #[no_mangle]
/// pub extern "C" fn drift2(_: K)->K{
///   let simple=new_list(qtype::ENUM_LIST, 2);
///   simple.as_mut_slice::<J>().copy_from_slice(&[0_i64, 1]);
///   // Convert an enum indices into a compound list while creating enum values from the indices which are tied with
///   //  an existing enum variable named "enum", i.e., Enum indices [0, 1] in the code are cast into `(enum[0]; enum[1])`.
///   let mut compound = simple_to_compound(simple, "enum");
///   // Add `enum2[2]`.
///   compound.push(new_enum("enum2", 2)).unwrap();
///   compound.push(new_month(3)).unwrap();
///   compound
/// }
/// ```
/// ```q
/// q)drift: LIBPATH_ (`drift; 1);
/// q)drift2: LIBPATH_ (`drift2; 1);
/// q)drift[]
/// 12i
/// 34i
/// `vague
/// -3000i
/// q)enum: `mashroom`broccoli`cucumber
/// q)enum2: `mackerel`swordfish`tuna
/// q)drift2[]
/// `enum$`mashroom
/// `enum$`broccoli
/// `enum2$`tuna
/// 2000.04m
/// ```
/// # Note
/// - To convert a list provided externally (i.e., passed from a q process), apply
///   [`increment_reference_count`](fn.increment_reference_count.html) before converting the list.
/// - Enum elements from different enum sources must be contained in a compound list. Therefore
///   this function intentionally restricts the number of enum sources to one so that user switches
///   a simple list to a compound list when the second enum sources are provided.
pub fn simple_to_compound(simple: K, enum_source: &str) -> K {
    let size = simple.len() as usize;
    let compound = new_list(qtype::COMPOUND_LIST, size as J);
    let compound_slice = compound.as_mut_slice::<K>();
    match simple.get_type() {
        qtype::BOOL_LIST => {
            let simple_slice = simple.as_mut_slice::<G>();
            for i in 0..size {
                compound_slice[i] = new_bool(simple_slice[i] as I);
            }
        }
        qtype::GUID_LIST => {
            let simple_slice = simple.as_mut_slice::<U>();
            for i in 0..size {
                compound_slice[i] = new_guid(simple_slice[i].guid);
            }
        }
        qtype::BYTE_LIST => {
            let simple_slice = simple.as_mut_slice::<G>();
            for i in 0..size {
                compound_slice[i] = new_byte(simple_slice[i] as I);
            }
        }
        qtype::SHORT_LIST => {
            let simple_slice = simple.as_mut_slice::<H>();
            for i in 0..size {
                compound_slice[i] = new_short(simple_slice[i] as I);
            }
        }
        qtype::INT_LIST => {
            let simple_slice = simple.as_mut_slice::<I>();
            for i in 0..size {
                compound_slice[i] = new_int(simple_slice[i]);
            }
        }
        qtype::LONG_LIST => {
            let simple_slice = simple.as_mut_slice::<J>();
            for i in 0..size {
                compound_slice[i] = new_long(simple_slice[i]);
            }
        }
        qtype::REAL_LIST => {
            let simple_slice = simple.as_mut_slice::<E>();
            for i in 0..size {
                compound_slice[i] = new_real(simple_slice[i] as F);
            }
        }
        qtype::FLOAT_LIST => {
            let simple_slice = simple.as_mut_slice::<F>();
            for i in 0..size {
                compound_slice[i] = new_float(simple_slice[i]);
            }
        }
        qtype::STRING => {
            let simple_slice = simple.as_mut_slice::<G>();
            for i in 0..size {
                compound_slice[i] = new_char(simple_slice[i] as char);
            }
        }
        qtype::SYMBOL_LIST => {
            let simple_slice = simple.as_mut_slice::<S>();
            for i in 0..size {
                compound_slice[i] = new_symbol(S_to_str(simple_slice[i]));
            }
        }
        qtype::TIMESTAMP_LIST => {
            let simple_slice = simple.as_mut_slice::<J>();
            for i in 0..size {
                compound_slice[i] = new_timestamp(simple_slice[i]);
            }
        }
        qtype::DATE_LIST => {
            let simple_slice = simple.as_mut_slice::<I>();
            for i in 0..size {
                compound_slice[i] = new_date(simple_slice[i]);
            }
        }
        qtype::TIME_LIST => {
            let simple_slice = simple.as_mut_slice::<I>();
            for i in 0..size {
                compound_slice[i] = new_time(simple_slice[i]);
            }
        }
        qtype::ENUM_LIST => {
            let simple_slice = simple.as_mut_slice::<J>();
            for i in 0..size {
                compound_slice[i] = new_enum(enum_source, simple_slice[i]);
            }
        }
        _ => {
            decrement_reference_count(compound);
            return new_error("not a simple list\0");
        }
    }
    // Free simple list
    decrement_reference_count(simple);
    compound
}