# kernel.rs.html -- source
Source to the Rust file `/Users/travis/.cargo/git/checkouts/ocl-21810c0a37a638dd/c345b5b/ocl/src/standard/kernel.rs`.
Keywords: rust, rustlang, rust-lang

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    //! An OpenCL kernel.

    use std;
    use std::ops::Deref;
    use std::any::Any;
    use std::any::TypeId;
    use std::collections::{HashMap, BTreeMap};
    use std::marker::PhantomData;
    use std::cell::RefCell;
    use std::borrow::Borrow;
    use core::ffi::c_void;
    use core::{self, util, OclPrm, Kernel as KernelCore, CommandQueue as CommandQueueCore, Mem as MemCore,
        ArgVal, KernelInfo, KernelInfoResult, KernelArgInfo, KernelArgInfoResult,
        KernelWorkGroupInfo, KernelWorkGroupInfoResult, AsMem, MemCmdAll, ClVersions};
    use core::error::{Result as OclCoreResult, ErrorKind as OclCoreErrorKind};
    use error::{Error as OclError, Result as OclResult};
    use standard::{SpatialDims, Program, Queue, WorkDims, Sampler, Device, ClNullEventPtrEnum,
        ClWaitListPtrEnum, Buffer, Image};
    pub use self::arg_type::{BaseType, Cardinality, ArgType};

    /// An error related to a `Kernel`, `KernelBuilder`, or `KernelCmd`.
    #[derive(Debug, Fail)]
    pub enum KernelError {
        #[fail(display = "No queue specified.")]
        CmdNoQueue,
        #[fail(display = "Global Work Size cannot be left unspecified. Set a default for \
            the kernel or specify one when enqueuing command.")]
        CmdNoGws,
        #[fail(display = "Unable to resolve argument named: '{}'. Ensure that an argument with \
            that name has been declared before building kernel.", _0)]
        NamedArgsInvalidArgName(String),
        #[fail(display = "No named arguments have been declared. Declare named arguments \
            when before building kernel.")]
        NamedArgsNone,
        #[fail(display = "Kernel arg index out of range. (kernel: {}, index: {})", _0, _1)]
        ArgIdxOor(String, u32),
        #[fail(display = "Kernel argument type mismatch. The argument named: '{}' at index: [{}] \
            should be a '{}' ({:?}).", arg_name, idx, ty_name, ty)]
        ArgTypeMismatch { idx: u32, arg_name: String, ty_name: String, ty: ArgType },
        #[fail(display = "No program specified.")]
        BuilderNoProgram,
        #[fail(display = "No kernel name specified.")]
        BuilderNoKernelName,
        #[fail(display = "The wrong number of kernel arguments have been specified \
            (required: {}, specified: {}). Use named arguments with 'None' or zero values to \
            declare arguments you plan to assign a value to at a later time.", required, specified)]
        BuilderWrongArgCount { required: u32, specified: u32 },
    }

    /// A kernel command builder used to enqueue a kernel with a mix of default
    /// and optionally specified arguments.
    #[must_use = "commands do nothing unless enqueued"]
    pub struct KernelCmd<'k> {
        kernel: &'k KernelCore,
        queue: Option<&'k CommandQueueCore>,
        gwo: SpatialDims,
        gws: SpatialDims,
        lws: SpatialDims,
        wait_events: Option<ClWaitListPtrEnum<'k>>,
        new_event: Option<ClNullEventPtrEnum<'k>>,
    }

    /// A kernel enqueue command.
    impl<'k> KernelCmd<'k> {
        /// Specifies a queue to use for this call only.
        ///
        /// Overrides the kernel's default queue if one is set. If no default
        /// queue is set, this method **must** be called before enqueuing the
        /// kernel.
        pub fn queue<'q, Q>(mut self, queue: &'q Q) -> KernelCmd<'k>
                where 'q: 'k, Q: 'k + AsRef<CommandQueueCore> {
            self.queue = Some(queue.as_ref());
            self
        }

        /// Specifies a global work offset for this call only.
        #[deprecated(since = "0.18.0", note = "Use `::global_work_offset` instead.")]
         pub fn gwo<D: Into<SpatialDims>>(mut self, gwo: D) -> KernelCmd<'k> {
            self.gwo = gwo.into();
            self
        }

        /// Specifies a global work size for this call only.
        #[deprecated(since = "0.18.0", note = "Use `::global_work_size` instead.")]
        pub fn gws<D: Into<SpatialDims>>(mut self, gws: D) -> KernelCmd<'k> {
            self.gws = gws.into();
            self
        }

        /// Specifies a local work size for this call only.
        #[deprecated(since = "0.18.0", note = "Use `::local_work_size` instead.")]
        pub fn lws<D: Into<SpatialDims>>(mut self, lws: D) -> KernelCmd<'k> {
            self.lws = lws.into();
            self
        }

        /// Specifies a global work offset for this call only.
         pub fn global_work_offset<D: Into<SpatialDims>>(mut self, gwo: D) -> KernelCmd<'k> {
            self.gwo = gwo.into();
            self
        }

        /// Specifies a global work size for this call only.
        pub fn global_work_size<D: Into<SpatialDims>>(mut self, gws: D) -> KernelCmd<'k> {
            self.gws = gws.into();
            self
        }

        /// Specifies a local work size for this call only.
        pub fn local_work_size<D: Into<SpatialDims>>(mut self, lws: D) -> KernelCmd<'k> {
            self.lws = lws.into();
            self
        }

        /// Specifies an event or list of events to wait on before the command
        /// will run.
        ///
        /// When events generated using the `::enew` method of **other**,
        /// previously enqueued commands are passed here (either individually or
        /// as part of an [`EventList`]), this command will not execute until
        /// those commands have completed.
        ///
        /// Using events can compliment the use of queues to order commands by
        /// creating temporal dependencies between them (where commands in one
        /// queue must wait for the completion of commands in another). Events can
        /// also supplant queues altogether when, for example, using out-of-order
        /// queues.
        ///
        /// # Example
        ///
        /// ```rust,ignore
        /// // Create an event list:
        /// let mut event_list = EventList::new();
        /// // Enqueue a kernel on `queue_1`, creating an event representing the kernel
        /// // command in our list:
        /// kernel.cmd().queue(&queue_1).enew(&mut event_list).enq()?;
        /// // Read from a buffer using `queue_2`, ensuring the read does not begin until
        /// // after the kernel command has completed:
        /// buffer.read(rwvec.clone()).queue(&queue_2).ewait(&event_list).enq_async()?;
        /// ```
        ///
        /// [`EventList`]: struct.EventList.html
        pub fn ewait<'e, Ewl>(mut self, ewait: Ewl) -> KernelCmd<'k>
                where 'e: 'k, Ewl: Into<ClWaitListPtrEnum<'e>> {
            self.wait_events = Some(ewait.into());
            self
        }

        /// Specifies the destination to store a new, optionally created event
        /// associated with this command.
        ///
        /// The destination can be a mutable reference to an empty event (created
        /// using [`Event::empty`]) or a mutable reference to an event list.
        ///
        /// After this command is enqueued, the event in the destination can be
        /// passed to the `::ewait` method of another command. Doing so will cause
        /// the other command to wait until this command has completed before
        /// executing.
        ///
        /// Using events can compliment the use of queues to order commands by
        /// creating temporal dependencies between them (where commands in one
        /// queue must wait for the completion of commands in another). Events can
        /// also supplant queues altogether when, for example, using out-of-order
        /// queues.
        ///
        /// # Example
        ///
        /// ```rust,ignore
        /// // Create an event list:
        /// let mut event = Event::empty();
        /// // Enqueue a kernel on `queue_1`, creating an event representing the kernel
        /// // command in our list:
        /// kernel.cmd().queue(&queue_1).enew(&mut event).enq()?;
        /// // Read from a buffer using `queue_2`, ensuring the read does not begin until
        /// // after the kernel command has completed:
        /// buffer.read(rwvec.clone()).queue(&queue_2).ewait(&event).enq_async()?;
        /// ```
        ///
        /// [`Event::empty`]: struct.Event.html#method.empty
        pub fn enew<'e, En>(mut self, new_event_dest: En) -> KernelCmd<'k>
                where 'e: 'k, En: Into<ClNullEventPtrEnum<'e>> {
            self.new_event = Some(new_event_dest.into());
            self
        }

        /// Enqueues this kernel command.
        ///
        /// # Safety
        ///
        /// All kernel code must be considered untrusted. Therefore the act of
        /// calling this function contains implied unsafety even though the API
        /// itself is safe.
        pub unsafe fn enq(self) -> OclResult<()> {
            let queue = match self.queue {
                Some(q) => q,
                None => return Err(KernelError::CmdNoQueue.into()),
            };

            let dim_count = self.gws.dim_count();

            let gws = match self.gws.to_work_size() {
                Some(gws) => gws,
                None => return Err(KernelError::CmdNoGws.into()),
            };

            core::enqueue_kernel(queue, &self.kernel, dim_count, self.gwo.to_work_offset(),
                &gws, self.lws.to_work_size(), self.wait_events, self.new_event)
                .map_err(OclError::from)
        }
    }

    /// Converts an argument index specifier to `u32`.
    #[derive(Clone, Copy, Debug)]
    pub enum ArgIdxSpecifier {
        Uint(u32),
        Str(&'static str),
    }

    impl ArgIdxSpecifier {
        // Resolves this specifier into an integer index using the specified
        // argument map if necessary.
        fn to_idx(&self, named_args: &NamedArgs) -> OclResult<u32> {
            match *self {
                ArgIdxSpecifier::Uint(idx) => Ok(idx),
                ArgIdxSpecifier::Str(s) => named_args.resolve_idx(s),
            }
        }
    }

    impl From<u32> for ArgIdxSpecifier {
        fn from(idx: u32) -> ArgIdxSpecifier {
            ArgIdxSpecifier::Uint(idx)
        }
    }

    impl From<i32> for ArgIdxSpecifier {
        fn from(idx: i32) -> ArgIdxSpecifier {
            ArgIdxSpecifier::Uint(idx as u32)
        }
    }

    impl From<usize> for ArgIdxSpecifier {
        fn from(idx: usize) -> ArgIdxSpecifier {
            ArgIdxSpecifier::Uint(idx as u32)
        }
    }

    impl From<&'static str> for ArgIdxSpecifier {
        fn from(s: &'static str) -> ArgIdxSpecifier {
            ArgIdxSpecifier::Str(s)
        }
    }

    /// Contains owned or shared argument values.
    #[derive(Debug, Clone)]
    enum ArgValKeeper<'b> {
        Shared(ArgVal<'b>),
        Owned(Vec<u8>),
    }

    impl<'b> ArgValKeeper<'b> {
        pub fn owned<T>(prm: T) -> ArgValKeeper<'b> where T: OclPrm {
            unsafe { ArgValKeeper::Owned(util::into_bytes(prm)) }
        }

        pub fn mem_null() -> ArgValKeeper<'b> {
            ArgValKeeper::Shared(ArgVal::mem_null())
        }

        /// Returns the size (in bytes) and raw pointer to the contained kernel
        /// argument value.
        pub fn to_arg_val(&'b self) -> ArgVal<'b> {
            match *self {
                ArgValKeeper::Shared(ref av) => av.clone(),
                ArgValKeeper::Owned(ref bytes) => {
                    unsafe { ArgVal::from_raw(bytes.len(), bytes.as_ptr() as *const c_void) }
                }
            }
        }
    }

    /// Wraps argument values of different types.
    pub struct ArgValConverter<'b, T> where T: OclPrm {
        val: ArgValKeeper<'b>,
        type_id: Option<TypeId>,
        mem: Option<MemCore>,
        _ty: PhantomData<T>,
    }

    impl<'b, T> From<Option<&'b Buffer<T>>> for ArgValConverter<'b, T> where T: OclPrm {
        /// Converts from an Option<`Buffer`>.
        fn from(buf: Option<&'b Buffer<T>>) -> ArgValConverter<'b, T> {
            let val = match buf {
                Some(b) => ArgValKeeper::Shared(ArgVal::mem(b)),
                None => ArgValKeeper::mem_null(),
            };

            ArgValConverter {
                val,
                type_id: Some(TypeId::of::<T>()),
                mem: buf.map(|b| b.as_mem().clone()),
                _ty: PhantomData,
            }
        }
    }

    impl<'b, T> From<&'b Buffer<T>> for ArgValConverter<'b, T> where T: OclPrm {
        /// Converts from a `Buffer`.
        fn from(buf: &'b Buffer<T>) -> ArgValConverter<'b, T> {
            ArgValConverter {
                val: ArgValKeeper::Shared(ArgVal::mem(buf)),
                type_id: Some(TypeId::of::<T>()),
                mem: Some(buf.as_mem().clone()),
                _ty: PhantomData,
            }
        }
    }

    impl<'b, T> From<&'b mut Buffer<T>> for ArgValConverter<'b, T> where T: OclPrm {
        fn from(buf: &'b mut Buffer<T>) -> ArgValConverter<'b, T> {
            ArgValConverter::from(&*buf)
        }
    }

    // impl<'b, T> From<&'b &'b Buffer<T>> for ArgValConverter<'b, T> where T: OclPrm {
    //     fn from(buf: &'b &'b Buffer<T>) -> ArgValConverter<'b, T> {
    //         ArgValConverter::from(&**buf)
    //     }
    // }

    impl<'b, T> From<Option<&'b Image<T>>> for ArgValConverter<'b, T> where T: OclPrm {
        /// Converts from an Option<`Image`>.
        fn from(img: Option<&'b Image<T>>) -> ArgValConverter<'b, T> {
            let val = match img {
                Some(i) => ArgValKeeper::Shared(ArgVal::mem(i)),
                None => ArgValKeeper::mem_null(),
            };

            ArgValConverter {
                val,
                type_id: None,
                mem: img.map(|i| i.as_mem().clone()),
                _ty: PhantomData,
            }
        }
    }

    impl<'b, T> From<&'b Image<T>> for ArgValConverter<'b, T> where T: OclPrm {
        /// Converts from an `Image`.
        fn from(img: &'b Image<T>) -> ArgValConverter<'b, T> {
            ArgValConverter {
                val: ArgValKeeper::Shared(ArgVal::mem(img)),
                type_id: None,
                mem: Some(img.as_mem().clone()),
                _ty: PhantomData,
            }
        }
    }

    impl<'b, T> From<&'b mut Image<T>> for ArgValConverter<'b, T> where T: OclPrm {
        fn from(img: &'b mut Image<T>) -> ArgValConverter<'b, T> {
            ArgValConverter::from(&*img)
        }
    }

    // impl<'b, T> From<&'b &'b Image<T>> for ArgValConverter<'b, T> where T: OclPrm {
    //     fn from(img: &'b &'b Image<T>) -> ArgValConverter<'b, T> {
    //         ArgValConverter::from(&**img)
    //     }
    // }

    impl<'b, T> From<&'b T> for ArgValConverter<'b, T> where T: OclPrm {
        /// Converts from a scalar or vector value.
        fn from(prm: &'b T) -> ArgValConverter<'b, T> {
            ArgValConverter {
                val: ArgValKeeper::Shared(ArgVal::scalar(prm)),
                type_id: Some(TypeId::of::<T>()),
                mem: None,
                _ty: PhantomData,
            }
        }
    }

    impl<'b, T> From<T> for ArgValConverter<'b, T> where T: OclPrm {
        /// Converts from a scalar or vector value.
        fn from(prm: T) -> ArgValConverter<'b, T> {
            ArgValConverter {
                val: ArgValKeeper::owned(prm),
                type_id: Some(TypeId::of::<T>()),
                mem: None,
                _ty: PhantomData,
            }
        }
    }

    /// A map of argument names -> indexes.
    #[derive(Clone, Debug)]
    struct NamedArgs(Option<HashMap<&'static str, u32>>);

    impl NamedArgs {
        /// Inserts a named argument into the map.
        fn insert(&mut self, name: &'static str, arg_idx: u32) {
            if self.0.is_none() {
                self.0 = Some(HashMap::with_capacity(8));
            }
            self.0.as_mut().unwrap().insert(name, arg_idx);
        }

        /// Resolves the index of a named argument with a friendly error message.
        fn resolve_idx(&self, name: &'static str) -> OclResult<u32> {
            match self.0 {
                Some(ref map) => {
                    match map.get(name) {
                        Some(&ai) => Ok(ai),
                        None => Err(KernelError::NamedArgsInvalidArgName(name.into()).into()),
                    }
                },
                None => Err(KernelError::NamedArgsNone.into()),
            }
        }
    }

    /// Storage for `Mem` arguments.
    #[derive(Clone, Debug)]
    struct MemArgs(Option<RefCell<BTreeMap<u32, MemCore>>>);

    impl MemArgs {
        /// Inserts a `Mem` argument for storage if possible.
        fn insert(&self, idx: u32, mem: MemCore) {
            if let Some(ref map) = self.0 {
                map.borrow_mut().insert(idx, mem);
            }
        }

        /// Removes a `Mem` argument.
        fn remove(&self, idx: &u32) {
            if let Some(ref map) = self.0 {
                map.borrow_mut().remove(idx);
            }
        }
    }

    /// A kernel which represents a 'procedure'.
    ///
    /// Corresponds to code which must have already been compiled into a program.
    ///
    /// Set arguments using `::set_arg` or any of the `::set_arg...` methods.
    ///
    /// `Kernel` includes features that a raw OpenCL kernel does not, including:
    ///
    /// 1. Type-checked arguments (not just size-checked)
    /// 2. Named arguments (with a `&'static str` name)
    /// 3. Prevention of a potential (difficult to debug) segfault if a buffer or
    ///    image used by a kernel is dropped prematurely.
    /// 4. Stored defaults for the:
    ///     - Queue
    ///     - Global Work Offset
    ///     - Global Work Size
    ///     - Local Work Size
    ///
    /// ### `Clone` and `Send`
    ///
    /// A `Kernel` may not be cloned but may be sent between threads. This ensures
    /// that no two threads create a race condition by attempting to set an
    /// argument and enqueue a kernel at the same time. Use the `KernelBuilder` to
    /// create multiple identical kernels (`KernelBuilder` is clonable and
    /// re-usable).
    #[derive(Debug)]
    pub struct Kernel {
        obj_core: KernelCore,
        named_args: NamedArgs,
        mem_args: MemArgs,
        queue: Option<Queue>,
        gwo: SpatialDims,
        gws: SpatialDims,
        lws: SpatialDims,
        arg_types: Option<Vec<ArgType>>,
    }

    impl Kernel {
        /// Returns a new `KernelBuilder`.
        pub fn builder<'p>() -> KernelBuilder<'p> {
            KernelBuilder::new()
        }

        /// Verifies that a type matches the kernel arg info:
        ///
        /// This function does nothing and always returns `Ok` if argument type
        /// checking is disabled by the user or for any other reason.
        ///
        /// Argument type checking will automatically be disabled if any of the
        /// devices in use do not support OpenCL version 1.2 or higher or if
        /// argument information is not available on the associated platform.
        fn verify_arg_type<T: OclPrm + Any>(&self, arg_idx: u32) -> OclResult<()> {
            if let Some(ref arg_types) = self.arg_types {
                let arg_type = arg_types.get(arg_idx as usize)
                    .ok_or(KernelError::ArgIdxOor(self.name()?, arg_idx))?;

                if arg_type.is_match::<T>() {
                    Ok(())
                } else {
                    let ty_name = arg_type_name(&self.obj_core, arg_idx)?;
                    let arg_name = arg_name(&self.obj_core, arg_idx)?;
                    Err(KernelError::ArgTypeMismatch { idx: arg_idx, arg_name,
                        ty_name, ty: arg_type.clone() }.into())
                }
            } else {
                Ok(())
            }
        }

        /// Returns the argument index of a named argument if it exists.
        pub fn named_arg_idx(&self, name: &'static str) -> Option<u32> {
            self.named_args.resolve_idx(name).ok()
        }

        /// Sets an argument by index without checks of any kind.
        ///
        /// Setting buffer or image (`cl_mem`) arguments this way may cause
        /// segfaults or errors if the buffer goes out of scope at any point
        /// before this kernel is dropped.
        ///
        /// This also bypasses the check to determine if the type of the value you
        /// pass here matches the type defined in your kernel.
        pub unsafe fn set_arg_unchecked(&self, arg_idx: u32, arg_val: ArgVal) -> OclResult<()> {
            core::set_kernel_arg(&self.obj_core, arg_idx, arg_val).map_err(OclError::from)
        }

        /// Sets an argument by index.
        fn _set_arg<T: OclPrm>(&self, arg_idx: u32, arg_val: ArgVal) -> OclResult<()> {
            self.verify_arg_type::<T>(arg_idx)?;
            core::set_kernel_arg(&self.obj_core, arg_idx, arg_val).map_err(OclError::from)
        }

        /// Sets a `Buffer`, `Image`, scalar, or vector argument by index or by
        /// name.
        ///
        /// ### Example
        /// ```rust,ignore
        /// // Create a kernel with arguments corresponding to those in the kernel.
        /// // Just for fun, one argument will be 'named':
        /// let kern = ocl_pq.kernel_builder("multiply_by_scalar")
        ///     .arg(&0)
        ///     .arg(None::<&Buffer<f32>>)
        ///     .arg_named("result", None::<&Buffer<f32>>)
        ///     .build()?;
        ///
        /// // Set our named argument. The Option<_> wrapper is, well... optional:
        /// kern.set_arg("result", &result_buffer)?;
        /// // We can also set arguments (named or not) by index. Just for
        /// // demonstration, we'll set one using an option:
        /// kern.set_arg(0, &COEFF)?;
        /// kern.set_arg(1, Some(&source_buffer))?;
        /// kern.set_arg(2, &result_buffer)?;
        /// ```
        pub fn set_arg<'a, T, Ai, Av>(&self, idx: Ai, arg: Av) -> OclResult<()>
                where T: OclPrm, Ai: Into<ArgIdxSpecifier>, Av: Into<ArgValConverter<'a, T>> {
            let arg_idx = idx.into().to_idx(&self.named_args)?;
            self.verify_arg_type::<T>(arg_idx)?;
            let arg: ArgValConverter<T> = arg.into();

            // If the `KernelArg` is a `Mem` variant, clone the `MemCore` it
            // refers to, store it in `self.mem_args`. This prevents a buffer
            // which has gone out of scope from being erroneously referred to when
            // this kernel is enqueued and causing either a misleading error
            // message or a hard to debug segfault depending on the platform.
            match arg.mem {
                Some(mem) => self.mem_args.insert(arg_idx, mem),
                None => self.mem_args.remove(&arg_idx),
            };

            let val = arg.val.to_arg_val();
            self._set_arg::<T>(arg_idx, val)
        }

        /// Modifies the kernel argument named: `name`.
        #[deprecated(since = "0.18.0", note = "Use `::set_arg` instead.")]
        pub fn set_arg_buf_named<'a, T, M>(&'a self, name: &'static str,
                buffer_opt: Option<M>) -> OclResult<()>
                where T: OclPrm, M: AsMem<T> + MemCmdAll {
            let arg_idx = self.named_args.resolve_idx(name)?;
            match buffer_opt {
                Some(buffer) => {
                    self.mem_args.insert(arg_idx, buffer.as_mem().clone());
                    self._set_arg::<T>(arg_idx, ArgVal::mem(buffer.as_mem()))
                },
                None => {
                    self.mem_args.remove(&arg_idx);
                    self._set_arg::<T>(arg_idx, ArgVal::mem_null())
                },
            }
        }

        /// Modifies the kernel argument named: `name`.
        #[deprecated(since = "0.18.0", note = "Use `::set_arg` instead.")]
        pub fn set_arg_img_named<'a, T, M>(&'a self, name: &'static str,
                image_opt: Option<M>) -> OclResult<()>
                where T: OclPrm, M: AsMem<T> + MemCmdAll {
            let arg_idx = self.named_args.resolve_idx(name)?;
            match image_opt {
                Some(img) => {
                    self.mem_args.insert(arg_idx, img.as_mem().clone());
                    self._set_arg::<T>(arg_idx, ArgVal::mem(img.as_mem()))
                },
                None => {
                    self.mem_args.remove(&arg_idx);
                    self._set_arg::<T>(arg_idx, ArgVal::mem_null())
                },
            }
        }

        /// Sets the value of a named sampler argument.
        #[deprecated(since = "0.18.0", note = "Use `::set_arg_sampler_named` instead.")]
        pub fn set_arg_smp_named<'a>(&'a self, name: &'static str,
                sampler_opt: Option<&Sampler>) -> OclResult<()> {
            let arg_idx = self.named_args.resolve_idx(name)?;
            match sampler_opt {
                Some(sampler) => self._set_arg::<u64>(arg_idx, ArgVal::sampler(sampler)),
                None => self._set_arg::<u64>(arg_idx, ArgVal::sampler_null()),
            }
        }

        /// Modifies the kernel argument named: `name`.
        #[deprecated(since = "0.18.0", note = "Use `::set_arg` instead.")]
        pub fn set_arg_scl_named<'a, T, B>(&'a self, name: &'static str, scalar: B)
                -> OclResult<()>
                where T: OclPrm, B: Borrow<T> {
            let arg_idx = self.named_args.resolve_idx(name)?;
            self._set_arg::<T>(arg_idx, ArgVal::scalar(scalar.borrow()))
        }

        /// Modifies the kernel argument named: `name`.
        #[deprecated(since = "0.18.0", note = "Use `::set_arg` instead.")]
        pub fn set_arg_vec_named<'a, T, B>(&'a self, name: &'static str, vector: B)
                -> OclResult<()>
                where T: OclPrm, B: Borrow<T> {
            let arg_idx = self.named_args.resolve_idx(name)?;
            self._set_arg::<T>(arg_idx, ArgVal::vector(vector.borrow()))
        }

        /// Sets the value of a named sampler argument.
        pub fn set_arg_sampler_named<'a, Ai>(&'a self, idx: Ai,
                sampler_opt: Option<&Sampler>) -> OclResult<()>
                where Ai: Into<ArgIdxSpecifier> {
            // let arg_idx = self.named_args.resolve_idx(name)?;
            let arg_idx = idx.into().to_idx(&self.named_args)?;
            match sampler_opt {
                Some(sampler) => self._set_arg::<u64>(arg_idx, ArgVal::sampler(sampler)),
                None => self._set_arg::<u64>(arg_idx, ArgVal::sampler_null()),
            }
        }

        /// Returns a command builder which is used to chain parameters of an
        /// 'enqueue' command together.
        pub fn cmd(&self) -> KernelCmd {
            KernelCmd {
                kernel: &self.obj_core,
                queue: self.queue.as_ref().map(|q| q.as_ref()),
                gwo: self.gwo,
                gws: self.gws,
                lws: self.lws,
                wait_events: None,
                new_event: None
            }
        }

        /// Enqueues this kernel on the default queue using the default work sizes
        /// and offsets.
        ///
        /// Shorthand for `.cmd().enq()`
        ///
        /// # Safety
        ///
        /// All kernel code must be considered untrusted. Therefore the act of
        /// calling this function contains implied unsafety even though the API
        /// itself is safe.
        pub unsafe fn enq(&self) -> OclResult<()> {
            self.cmd().enq()
        }

        /// Changes the default queue.
        ///
        /// Returns a ref for chaining i.e.:
        ///
        /// `kernel.set_default_queue(queue).enqueue(....);`
        ///
        /// Even when used as above, the queue is changed permanently,
        /// not just for the one call. Changing the queue is cheap so feel free
        /// to change as often as needed.
        ///
        /// If you want to change the queue for only a single call, use:
        /// `::cmd.queue(...)...enq()...`
        ///
        /// The new queue must be associated with a device associated with the
        /// kernel's program.
        ///
        pub fn set_default_queue(&mut self, queue: Queue) -> &mut Kernel {
            self.queue = Some(queue);
            self
        }

        /// Returns the default global work offset.
        #[deprecated(since = "0.18.0", note = "Use `::global_work_offset` instead.")]
        pub fn get_gwo(&self) -> SpatialDims {
            self.gwo
        }

        /// Returns the default global work size.
        #[deprecated(since = "0.18.0", note = "Use `::global_work_size` instead.")]
        pub fn get_gws(&self) -> SpatialDims {
            self.gws
        }

        /// Returns the default local work size.
        #[deprecated(since = "0.18.0", note = "Use `::local_work_size` instead.")]
        pub fn get_lws(&self) -> SpatialDims {
            self.lws
        }

        /// Sets the default global work offset.
        pub fn set_default_global_work_offset(&mut self, gwo: SpatialDims) -> &mut Kernel {
            self.gwo = gwo;
            self
        }

        /// Sets the default global work size.
        pub fn set_default_global_work_size(&mut self, gws: SpatialDims) -> &mut Kernel {
            self.gws = gws;
            self
        }

        /// Sets the default local work size.
        pub fn set_default_local_work_size(&mut self, lws: SpatialDims) -> &mut Kernel {
            self.lws = lws;
            self
        }

        /// Returns the default queue for this kernel if one has been set.
        pub fn default_queue<'a>(&'a self) -> Option<&'a Queue> {
            self.queue.as_ref()
        }

        /// Returns the default global work offset.
        pub fn default_global_work_offset(&self) -> SpatialDims {
            self.gwo
        }

        /// Returns the default global work size.
        pub fn default_global_work_size(&self) -> SpatialDims {
            self.gws
        }

        /// Returns the default local work size.
        pub fn default_local_work_size(&self) -> SpatialDims {
            self.lws
        }

        /// Returns a reference to the core pointer wrapper, usable by functions in
        /// the `core` module.
        #[inline]
        pub fn as_core<'a>(&'a self) -> &'a KernelCore {
            self
        }

        /// Returns information about this kernel.
        pub fn info(&self, info_kind: KernelInfo) -> OclCoreResult<KernelInfoResult> {
            core::get_kernel_info(&self.obj_core, info_kind)
        }

        /// Returns work group information for this kernel.
        pub fn wg_info(&self, device: Device, info_kind: KernelWorkGroupInfo)
                -> OclCoreResult<KernelWorkGroupInfoResult> {
            core::get_kernel_work_group_info(&self.obj_core, device, info_kind)
        }

        /// Returns argument information for this kernel.
        pub fn arg_info(&self, arg_idx: u32, info_kind: KernelArgInfo)
                -> OclCoreResult<KernelArgInfoResult> {
            arg_info(&*self.as_core(), arg_idx, info_kind)
        }

        /// Returns the name of this kernel.
        pub fn name(&self) -> OclCoreResult<String> {
            core::get_kernel_info(&self.obj_core, KernelInfo::FunctionName).map(|r| r.into())
        }

        /// Returns the number of arguments this kernel has.
        pub fn num_args(&self) -> OclCoreResult<u32> {
            match core::get_kernel_info(&self.obj_core, KernelInfo::NumArgs) {
                Ok(KernelInfoResult::NumArgs(num)) => Ok(num),
                Err(err) => Err(err),
                _=> unreachable!(),
            }
        }

        fn fmt_info(&self, f: &mut std::fmt::Formatter) -> std::fmt::Result {
            f.debug_struct("Kernel")
                .field("FunctionName", &self.info(KernelInfo::FunctionName))
                .field("ReferenceCount", &self.info(KernelInfo::ReferenceCount))
                .field("Context", &self.info(KernelInfo::Context))
                .field("Program", &self.info(KernelInfo::Program))
                .field("Attributes", &self.info(KernelInfo::Attributes))
                .finish()
        }

        // fn fmt_arg_info(&self, f: &mut std::fmt::Formatter) -> std::fmt::Result {
        //     f.debug_struct("Kernel")
        //         .field("FunctionName", &self.info(KernelInfo::FunctionName))
        //         .field("ReferenceCount", &self.info(KernelInfo::ReferenceCount))
        //         .field("Context", &self.info(KernelInfo::Context))
        //         .field("Program", &self.info(KernelInfo::Program))
        //         .field("Attributes", &self.info(KernelInfo::Attributes))
        //         .finish()
        // }

        fn fmt_wg_info<D>(&self, f: &mut std::fmt::Formatter, devices: Vec<D>) -> std::fmt::Result
                where D: Into<Device> {
            for device in devices {
                let device = device.into();
                if !device.vendor().unwrap()
                        .contains("NVIDIA") {
                    f.debug_struct("WorkGroup")
                        .field("WorkGroupSize", &self.wg_info(device, KernelWorkGroupInfo::WorkGroupSize))
                        .field("CompileWorkGroupSize", &self.wg_info(device, KernelWorkGroupInfo::CompileWorkGroupSize))
                        .field("LocalMemSize", &self.wg_info(device, KernelWorkGroupInfo::LocalMemSize))
                        .field("PreferredWorkGroupSizeMultiple",
                            &self.wg_info(device, KernelWorkGroupInfo::PreferredWorkGroupSizeMultiple))
                        .field("PrivateMemSize", &self.wg_info(device, KernelWorkGroupInfo::PrivateMemSize))
                        // .field("GlobalWorkSize", &self.wg_info(device, KernelWorkGroupInfo::GlobalWorkSize))
                        .finish()?;
                }
            }
            Ok(())
        }
    }

    impl std::fmt::Display for Kernel {
        fn fmt(&self, f: &mut std::fmt::Formatter) -> std::fmt::Result {
            self.fmt_info(f)?;
            write!(f, " ")?;
            self.fmt_wg_info(f, self.obj_core.devices().unwrap())
        }
    }

    impl Deref for Kernel {
        type Target = KernelCore;

        fn deref<'a>(&'a self) -> &'a KernelCore {
            &self.obj_core
        }
    }

    impl Clone for Kernel {
        /// Creates a new, identical kernel.
        fn clone(&self) -> Kernel {
            unimplemented!();
        }
    }

    /// A kernel builder.
    ///
    ///
    /// ### Examples
    ///
    /// ```rust,ignore
    /// // Create a kernel:
    /// let kernel = Kernel::builder()
    ///     .program(&program)
    ///     .name("process")
    ///     .queue(queue.clone())
    ///     .global_work_size(&gws_patch_count)
    ///     .arg(&(patch_size as i32))
    ///     .arg(&source_buffer)
    ///     .arg(&destination_buffer)
    ///     .build()?;
    /// ```
    ///
    /// Re-use and clone:
    ///
    /// ```rust,ignore
    /// // Create a builder for re-use:
    /// let builder = Kernel::builder()
    ///     .program(&program)
    ///     .name("process")
    ///     .queue(queue.clone())
    ///     .global_work_size([512, 64, 64])
    ///     .arg(&(patch_size as i32))
    ///     .arg(&source_buffer)
    ///     .arg_named("dest", &destination_buffer);
    ///
    /// // Create multiple kernels using the same builder:
    /// let kernel_0 = builder.build()?;
    /// let kernel_1 = builder.build()?;
    ///
    /// // Clone the builder:
    /// let mut builder_clone = builder.clone();
    ///
    /// // Modify a default parameter:
    /// builder_clone.global_work_size([1024, 128, 128]);
    ///
    /// // Create another kernel using the cloned builder:
    /// let kernel_2 = builder_clone.build()?;
    ///
    /// // Modify one of the arguments using the created kernel directly
    /// // (arguments cannot be modified using the builder):
    /// kernel_2.set_arg("dest", &alternate_destination_buffer)?;
    ///
    /// // Arguments can also be referred to by index:
    /// kernel_2.set_arg(1, &alternate_source_buffer)?;
    /// ```
    ///
    #[derive(Debug)]
    pub struct KernelBuilder<'b> {
        program: Option<&'b Program>,
        name: Option<String>,
        named_args: NamedArgs,
        mem_args: MemArgs,
        args: Vec<(ArgValKeeper<'b>, Option<TypeId>)>,
        queue: Option<Queue>,
        gwo: SpatialDims,
        gws: SpatialDims,
        lws: SpatialDims,
        disable_arg_check: bool,
    }

    impl<'b> KernelBuilder<'b> {
        /// Returns a new kernel builder.
        pub fn new() -> KernelBuilder<'b> {
            KernelBuilder {
                program: None,
                name: None,
                named_args: NamedArgs(None),
                args: Vec::with_capacity(16),
                mem_args: MemArgs(Some(RefCell::new(BTreeMap::new()))),
                queue: None,
                gwo: SpatialDims::Unspecified,
                gws: SpatialDims::Unspecified,
                lws: SpatialDims::Unspecified,
                disable_arg_check: false,
            }
        }

        /// Specifies a program object with a successfully built executable.
        pub fn program<'s>(&'s mut self, program: &'b Program) -> &'s mut KernelBuilder<'b> {
            self.program = Some(program);
            self
        }

        /// Specifies a function name in the program declared with the `__kernel`
        /// qualifier (e.g. `__kernel void add_values(...`).
        pub fn name<'s, S>(&'s mut self, name: S) -> &'s mut KernelBuilder<'b>
                where S: Into<String> {
            self.name = Some(name.into());
            self
        }

        /// Sets the default queue to be used by all subsequent enqueue commands
        /// unless otherwise changed (with `::set_default_queue`) or overridden
        /// (by `::cmd().queue(...)...`).
        ///
        /// The queue must be associated with a device associated with the
        /// kernel's program.
        pub fn queue<'s>(&'s mut self, queue: Queue) -> &'s mut KernelBuilder<'b> {
            self.queue = Some(queue);
            self
        }

        /// Sets the default global work offset.
        ///
        /// Used when enqueuing kernel commands. Superseded if specified while
        /// building a queue command with `::cmd`.
        #[deprecated(since = "0.18.0", note = "Use `::global_work_offset` instead.")]
        pub fn gwo<'s, D: Into<SpatialDims>>(&'s mut self, gwo: D) -> &'s mut KernelBuilder<'b> {
            self.gwo = gwo.into();
            self
        }

        /// Sets the default global work size.
        ///
        /// Used when enqueuing kernel commands. Superseded if specified while
        /// building a queue command with `::cmd`.
        #[deprecated(since = "0.18.0", note = "Use `::global_work_size` instead.")]
        pub fn gws<'s, D: Into<SpatialDims>>(&'s mut self, gws: D) -> &'s mut KernelBuilder<'b> {
            self.gws = gws.into();
            self
        }

        /// Sets the default local work size.
        ///
        /// Used when enqueuing kernel commands. Superseded if specified while
        /// building a queue command with `::cmd`.
        #[deprecated(since = "0.18.0", note = "Use `::local_work_size` instead.")]
        pub fn lws<'s, D: Into<SpatialDims>>(&'s mut self, lws: D) -> &'s mut KernelBuilder<'b> {
            self.lws = lws.into();
            self
        }

        /// Sets the default global work offset.
        ///
        /// Used when enqueuing kernel commands. Superseded if specified while
        /// building a queue command with `::cmd`.
        pub fn global_work_offset<'s, D: Into<SpatialDims>>(&'s mut self, gwo: D) -> &'s mut KernelBuilder<'b> {
            self.gwo = gwo.into();
            self
        }

        /// Sets the default global work size.
        ///
        /// Used when enqueuing kernel commands. Superseded if specified while
        /// building a queue command with `::cmd`.
        pub fn global_work_size<'s, D: Into<SpatialDims>>(&'s mut self, gws: D) -> &'s mut KernelBuilder<'b> {
            self.gws = gws.into();
            self
        }

        /// Sets the default local work size.
        ///
        /// Used when enqueuing kernel commands. Superseded if specified while
        /// building a queue command with `::cmd`.
        pub fn local_work_size<'s, D: Into<SpatialDims>>(&'s mut self, lws: D) -> &'s mut KernelBuilder<'b> {
            self.lws = lws.into();
            self
        }

        /// Adds a new argument to the kernel and returns the index.
        fn new_arg(&mut self, arg_val: ArgValKeeper<'b>, type_id: Option<TypeId>, mem: Option<MemCore>) -> u32 {
            let arg_idx = self.args.len() as u32;

            // If the `KernelArg` is a `Mem` variant, clone the `MemCore` it
            // refers to, store it in `self.mem_args`. This prevents a buffer
            // which has gone out of scope from being erroneously referred to when
            // this kernel is enqueued and causing either a misleading error
            // message or a hard to debug segfault depending on the platform.
            match mem {
                Some(mem) => self.mem_args.insert(arg_idx, mem),
                None => self.mem_args.remove(&arg_idx),
            };

            self.args.push((arg_val, type_id));
            arg_idx
        }

        /// Non-builder-style version of `::arg_buf()`.
        fn new_arg_buf<T, M>(&mut self, buffer_opt: Option<&'b M>) -> u32
                where T: OclPrm, M: 'b + AsMem<T> + MemCmdAll {
            match buffer_opt {
                Some(buffer) => {
                    self.new_arg(ArgValKeeper::Shared(ArgVal::mem(buffer.as_mem())),
                        Some(TypeId::of::<T>()),
                        Some(buffer.as_mem().clone()))
                },
                None => {
                    self.new_arg(ArgValKeeper::mem_null(),
                        Some(TypeId::of::<T>()), None)
                },
            }
        }

        /// Non-builder-style version of `::arg_img()`.
        fn new_arg_img<T, M>(&mut self, image_opt: Option<&'b M>) -> u32
                where T: OclPrm, M: 'b + AsMem<T> + MemCmdAll {
            match image_opt {
                Some(image) => {
                    // Type is ignored:
                    self.new_arg(ArgValKeeper::Shared(ArgVal::mem(image.as_mem())), None,
                        Some(image.as_mem().clone()))
                },
                None => {
                    self.new_arg(ArgValKeeper::mem_null(), None, None)
                },
            }
        }

        /// Non-builder-style version of `::arg_img()`.
        fn new_arg_smp(&mut self, sampler_opt: Option<&'b Sampler>) -> u32 {
            match sampler_opt {
                Some(sampler) => {
                    // Type is ignored:
                    self.new_arg(ArgValKeeper::Shared(ArgVal::sampler(sampler)), None, None)
                },
                None => {
                    self.new_arg(ArgValKeeper::Shared(ArgVal::sampler_null()), None, None)
                },
            }
        }

        /// Non-builder-style version of `::arg_scl()`.
        fn new_arg_scl<T>(&mut self, scalar: T) -> u32
                where T: OclPrm {
            self.new_arg(ArgValKeeper::owned(scalar), Some(TypeId::of::<T>()), None)
        }

        /// Non-builder-style version of `::arg_vec()`.
        fn new_arg_vec<T>(&mut self, vector: T) -> u32
                where T: OclPrm {
            self.new_arg(ArgValKeeper::owned(vector), Some(TypeId::of::<T>()), None)
        }

        /// Non-builder-style version of `::arg_loc()`.
        fn new_arg_loc<T>(&mut self, length: usize) -> u32
                where T: OclPrm {
            self.new_arg(ArgValKeeper::Shared(ArgVal::local::<T>(&length)), None, None)
        }

        /// Adds a new `Buffer`, `Image`, scalar, or vector argument to the
        /// kernel.
        ///
        /// The argument is added to the bottom of the argument order.
        ///
        /// ### Example
        ///
        /// ```rust,ignore
        /// let kern = ocl_pq.kernel_builder("multiply_by_scalar")
        ///     .arg(&100.0f32)
        ///     .arg(&source_buffer)
        ///     .arg(&result_buffer)
        ///     .build()?;
        /// ```
        pub fn arg<'s, T, A>(&'s mut self, arg: A) -> &'s mut KernelBuilder<'b>
                where T: OclPrm, A: Into<ArgValConverter<'b, T>> {
            let arg = arg.into();
            self.new_arg(arg.val, arg.type_id, arg.mem);
            self
        }

        /// Adds a new argument to the kernel specifying the buffer object represented
        /// by 'buffer'.
        ///
        /// The argument is added to the bottom of the argument order.
        #[deprecated(since = "0.18", note = "Use ::arg instead.")]
        pub fn arg_buf<'s, T, M>(&'s mut self, buffer: &'b M) -> &'s mut KernelBuilder<'b>
                where T: OclPrm, M: 'b + AsMem<T> + MemCmdAll {
            self.new_arg_buf::<T, _>(Some(buffer));
            self
        }

        /// Adds a new argument to the kernel specifying the image object represented
        /// by 'image'.
        ///
        /// The argument is added to the bottom of the argument order.
        #[deprecated(since = "0.18", note = "Use ::arg instead.")]
        pub fn arg_img<'s, T, M>(&'s mut self, image: &'b M) -> &'s mut KernelBuilder<'b>
                where T: OclPrm, M: 'b + AsMem<T> + MemCmdAll {
            self.new_arg_img::<T, _>(Some(image));
            self
        }

        /// Adds a new argument to the kernel specifying the sampler object represented
        /// by 'sampler'. Argument is added to the bottom of the argument
        /// order.
        #[deprecated(since = "0.18", note = "Use ::arg_sampler instead.")]
        pub fn arg_smp<'s>(&'s mut self, sampler: &'b Sampler) -> &'s mut KernelBuilder<'b> {
            self.new_arg_smp(Some(sampler));
            self
        }

        /// Adds a new argument specifying the value: `scalar`.
        ///
        /// The argument is added to the bottom of the argument order.
        #[deprecated(since = "0.18", note = "Use ::arg instead.")]
        pub fn arg_scl<'s, T>(&'s mut self, scalar: T) -> &'s mut KernelBuilder<'b>
                where T: OclPrm {
            self.new_arg_scl(scalar);
            self
        }

        /// Adds a new argument specifying the value: `vector`.
        ///
        /// The argument is added to the bottom of the argument order.
        #[deprecated(since = "0.18", note = "Use ::arg instead.")]
        pub fn arg_vec<'s, T>(&'s mut self, vector: T) -> &'s mut KernelBuilder<'b>
                where T: OclPrm {
            self.new_arg_vec(vector);
            self
        }

        /// Adds a new argument specifying the allocation of a local variable of size
        /// `length * sizeof(T)` bytes (builder_style).
        ///
        /// The argument is added to the bottom of the argument order.
        ///
        /// Local variables are used to share data between work items in the same
        /// workgroup.
        #[deprecated(since = "0.18", note = "Use ::arg_local instead.")]
        pub fn arg_loc<'s, T>(&'s mut self, length: usize) -> &'s mut KernelBuilder<'b>
                where T: OclPrm {
            self.new_arg_loc::<T>(length);
            self
        }

        /// Adds a new argument to the kernel specifying the sampler object represented
        /// by 'sampler'. Argument is added to the bottom of the argument
        /// order.
        pub fn arg_sampler<'s>(&'s mut self, sampler: &'b Sampler) -> &'s mut KernelBuilder<'b> {
            self.new_arg_smp(Some(sampler));
            self
        }

        /// Adds a new argument specifying the allocation of a local variable of size
        /// `length * sizeof(T)` bytes (builder_style).
        ///
        /// The argument is added to the bottom of the argument order.
        ///
        /// Local variables are used to share data between work items in the same
        /// workgroup.
        pub fn arg_local<'s, T>(&'s mut self, length: usize) -> &'s mut KernelBuilder<'b>
                where T: OclPrm {
            self.new_arg_loc::<T>(length);
            self
        }

        /// Adds a new *named* `Buffer`, `Image`, scalar, or vector argument to the
        /// kernel.
        ///
        /// The argument is added to the bottom of the argument order.
        ///
        /// To set a `Buffer` or `Image` argument to `None` (null), you must use a
        /// type annotation (e.g. `None::<&Buffer<f32>>`). Scalar and vector
        /// arguments may not be null; use zero (e.g. `&0`) instead.
        ///
        /// Named arguments can be modified later using `::set_arg()`.
        ///
        /// ### Example
        ///
        /// ```rust,ignore
        /// // Create a kernel with arguments corresponding to those in the kernel.
        /// // One argument will be 'named':
        /// let kern = ocl_pq.kernel_builder("multiply_by_scalar")
        ///     .arg(&COEFF)
        ///     .arg(&source_buffer)
        ///     .arg_named("result", None::<&Buffer<f32>>)
        ///     .build()?;
        ///
        /// // Set our named argument. The Option<_> wrapper is, well... optional:
        /// kern.set_arg("result", &result_buffer)?;
        /// // We can also set arguments (named or not) by index:
        /// kern.set_arg(2, &result_buffer)?;
        /// ```
        pub fn arg_named<'s, T, A>(&'s mut self, name: &'static str, arg: A) -> &'s mut KernelBuilder<'b>
                where T: OclPrm, A: Into<ArgValConverter<'b, T>> {
            let arg = arg.into();
            let arg_idx = self.new_arg(arg.val, arg.type_id, arg.mem);
            self.named_args.insert(name, arg_idx);
            self
        }

        /// Adds a new *named* argument specifying the buffer object represented by
        /// 'buffer'.
        ///
        /// The argument is added to the bottom of the argument order.
        ///
        /// Named arguments can be easily modified later using `::set_arg_buf_named()`.
        #[deprecated(since = "0.18", note = "Use ::arg_named instead.")]
        pub fn arg_buf_named<'s, T, M>(&'s mut self, name: &'static str, buffer_opt: Option<&'b M>) -> &'s mut KernelBuilder<'b>
                where T: OclPrm, M: 'b + AsMem<T> + MemCmdAll {
            let arg_idx = self.new_arg_buf::<T, _>(buffer_opt);
            self.named_args.insert(name, arg_idx);
            self
        }

        /// Adds a new *named* argument specifying the image object represented by
        /// 'image'.
        ///
        /// The argument is added to the bottom of the argument order.
        ///
        /// Named arguments can be easily modified later using `::set_arg_img_named()`.
        #[deprecated(since = "0.18", note = "Use ::arg_named instead.")]
        pub fn arg_img_named<'s, T, M>(&'s mut self, name: &'static str, image_opt: Option<&'b M>) -> &'s mut KernelBuilder<'b>
                where T: OclPrm, M: 'b + AsMem<T> + MemCmdAll {
            let arg_idx = self.new_arg_img::<T, _>(image_opt);
            self.named_args.insert(name, arg_idx);
            self
        }

        /// Adds a new *named* argument specifying the sampler object represented by
        /// 'sampler'.
        ///
        /// The argument is added to the bottom of the argument order.
        ///
        /// Named arguments can be easily modified later using `::set_arg_smp_named()`.
        #[deprecated(since = "0.18", note = "Use ::arg_sampler_named instead.")]
        pub fn arg_smp_named<'s>(&'s mut self, name: &'static str, sampler_opt: Option<&'b Sampler>) -> &'s mut KernelBuilder<'b> {
            let arg_idx = self.new_arg_smp(sampler_opt);
            self.named_args.insert(name, arg_idx);
            self
        }

        /// Adds a new *named* argument  specifying the value: `scalar`.
        ///
        /// The argument is added to the bottom of the argument order.
        ///
        /// Scalar arguments may not be null, use zero (e.g. `&0`) instead.
        ///
        /// Named arguments can be easily modified later using `::set_arg_scl_named()`.
        #[deprecated(since = "0.18", note = "Use ::arg_named instead.")]
        pub fn arg_scl_named<'s, T>(&'s mut self, name: &'static str, scalar: T) -> &'s mut KernelBuilder<'b>
                where T: OclPrm {
            let arg_idx = self.new_arg_scl(scalar);
            self.named_args.insert(name, arg_idx);
            self
        }

        /// Adds a new *named* argument specifying the value: `vector`.
        ///
        /// The argument is added to the bottom of the argument order.
        ///
        /// Vector arguments may not be null, use zero (e.g. `&0`) instead.
        ///
        /// Named arguments can be easily modified later using `::set_arg_vec_named()`.
        #[deprecated(since = "0.18", note = "Use ::arg_named instead.")]
        pub fn arg_vec_named<'s, T>(&'s mut self, name: &'static str, vector: T) -> &'s mut KernelBuilder<'b>
                where T: OclPrm {
            let arg_idx = self.new_arg_vec(vector);
            self.named_args.insert(name, arg_idx);
            self
        }

        /// Adds a new *named* argument specifying the sampler object represented by
        /// 'sampler'.
        ///
        /// The argument is added to the bottom of the argument order.
        ///
        /// Named arguments can be easily modified later using `::set_arg_smp_named()`.
        pub fn arg_sampler_named<'s>(&'s mut self, name: &'static str, sampler_opt: Option<&'b Sampler>) -> &'s mut KernelBuilder<'b> {
            let arg_idx = self.new_arg_smp(sampler_opt);
            self.named_args.insert(name, arg_idx);
            self
        }

        /// Specifies whether or not to store a copy of memory objects (`Buffer`
        /// and `Image`).
        ///
        /// ### Safety
        ///
        /// Disabling memory object argument retention can lead to a misleading
        /// error message or a difficult to debug segfault (depending on the
        /// platform) *if* a memory object is dropped before a kernel referring to
        /// it is enqueued. Only disable this if you are certain all of the memory
        /// objects set as kernel arguments will outlive the `Kernel` itself.
        pub unsafe fn disable_mem_arg_retention<'s>(&'s mut self) -> &'s mut KernelBuilder<'b> {
            self.mem_args = MemArgs(None);
            self
        }

        /// Disables argument type checking when setting arguments.
        ///
        /// Because the performance cost of argument type checking is negligible,
        /// disabling is not recommended.
        ///
        /// Argument type checking will automatically be disabled if any of the
        /// devices in use do not support OpenCL version 1.2 or higher or if
        /// argument information is not available on the associated platform.
        pub unsafe fn disable_arg_type_check<'s>(&'s mut self) -> &'s mut KernelBuilder<'b> {
            self.disable_arg_check = true;
            self
        }

        /// Builds and returns a new `Kernel`
        pub fn build(&self) -> OclResult<Kernel> {
            let program = self.program.ok_or(KernelError::BuilderNoProgram)?;
            let name = self.name.as_ref().ok_or(KernelError::BuilderNoKernelName)?;

            let obj_core = core::create_kernel(program, name)?;

            let num_args = match core::get_kernel_info(&obj_core, KernelInfo::NumArgs) {
                Ok(KernelInfoResult::NumArgs(num)) => num,
                Err(err) => return Err(OclError::from(err)),
                _=> unreachable!(),
            };

            if self.args.len() as u32 != num_args {
                return Err(KernelError::BuilderWrongArgCount {
                    required: num_args,
                    specified: self.args.len() as u32,
                 }.into())
            }

            let mut arg_types = Vec::with_capacity(num_args as usize);
            let mut all_arg_types_unknown = true;
            let mut disable_arg_check = false;

            // Cache argument types for later use, bypassing if the OpenCL version
            // is too low (v1.1).
            for arg_idx in 0..num_args {
                let arg_type = match ArgType::from_kern_and_idx(&obj_core, arg_idx) {
                    Ok(at) => {
                        if !at.is_unknown() { all_arg_types_unknown = false; }
                        at
                    },
                    Err(e) => {
                        if let OclCoreErrorKind::VersionLow { .. } = *e.kind() {
                            disable_arg_check = true;
                            break;
                        }
                        return Err(OclError::from(e));
                    },
                };
                arg_types.push(arg_type);
            }

            // Check argument types then set arguments.
            for (arg_idx, &(ref arg, ref type_id_opt)) in self.args.iter().enumerate() {
                if !disable_arg_check {
                    if let Some(type_id) = *type_id_opt {
                        if !arg_types[arg_idx].matches(type_id) {
                            let ty_name = arg_type_name(&obj_core, arg_idx as u32)?;
                            let arg_name = arg_name(&obj_core, arg_idx as u32)?;
                            return Err(KernelError::ArgTypeMismatch { idx: arg_idx as u32,
                                arg_name, ty_name, ty: arg_types[arg_idx].clone() }.into());
                        }
                    }
                }

                let val = arg.to_arg_val();
                core::set_kernel_arg(&obj_core, arg_idx as u32, val)?;
            }

            let arg_types = if all_arg_types_unknown || disable_arg_check {
                None
            } else {
                Some(arg_types)
            };

            Ok(Kernel {
                obj_core: obj_core,
                named_args: self.named_args.clone(),
                mem_args: self.mem_args.clone(),
                queue: self.queue.clone(),
                gwo: self.gwo,
                gws: self.gws,
                lws: self.lws,
                arg_types,
            })
        }
    }

    /// Returns argument information for a kernel.
    pub fn arg_info(core: &KernelCore, arg_idx: u32, info_kind: KernelArgInfo)
            -> OclCoreResult<KernelArgInfoResult> {
        let device_versions = match core.device_versions() {
            Ok(vers) => vers,
            Err(e) => return Err(e.into()),
        };

        core::get_kernel_arg_info(core, arg_idx, info_kind,
            Some(&device_versions))
    }

    /// Returns the type name for a kernel argument at the specified index.
    pub fn arg_type_name(core: &KernelCore, arg_idx: u32) -> OclCoreResult<String> {
        match arg_info(core, arg_idx, KernelArgInfo::TypeName) {
            Ok(KernelArgInfoResult::TypeName(type_name)) => Ok(type_name),
            Err(err) => Err(err.into()),
            _ => unreachable!(),
        }
    }

    /// Returns the type name for a kernel argument at the specified index.
    pub fn arg_name(core: &KernelCore, arg_idx: u32) -> OclCoreResult<String> {
        match arg_info(core, arg_idx, KernelArgInfo::Name) {
            Ok(KernelArgInfoResult::Name(name)) => Ok(name),
            Err(err) => Err(err.into()),
            _ => unreachable!(),
        }
    }

    pub mod arg_type {
        #![allow(unused_imports)]
        use std::any::{Any, TypeId};
        use ffi::{cl_char, cl_uchar, cl_short, cl_ushort, cl_int, cl_uint, cl_long, cl_ulong,
            cl_half, cl_float, cl_double, cl_bool, cl_bitfield};
        use core::{Error as OclCoreError, Result as OclCoreResult, Status, OclPrm, Kernel as KernelCore};
        use error::{Error as OclError, Result as OclResult};
        use standard::Sampler;
        use super::{arg_info, arg_type_name};

        pub use core::{
            Char, Char2, Char3, Char4, Char8, Char16,
            Uchar, Uchar2, Uchar3, Uchar4, Uchar8, Uchar16,
            Short, Short2, Short3, Short4, Short8, Short16,
            Ushort, Ushort2, Ushort3, Ushort4, Ushort8, Ushort16,
            Int, Int2, Int3, Int4, Int8, Int16,
            Uint, Uint2, Uint3, Uint4, Uint8, Uint16,
            Long, Long2, Long3, Long4, Long8, Long16,
            Ulong, Ulong2, Ulong3, Ulong4, Ulong8, Ulong16,
            Float, Float2, Float3, Float4, Float8, Float16,
            Double, Double2, Double3, Double4, Double8, Double16};

        /// The base type of an OpenCL primitive.
        #[derive(Clone, Debug, Copy, PartialEq, Eq)]
        pub enum BaseType {
            Char,
            Uchar,
            Short,
            Ushort,
            Int,
            Uint,
            Long,
            Ulong,
            Float,
            Double,
            Sampler,
            Image,
            Unknown,
        }

        /// The cardinality of an OpenCL primitive.
        ///
        /// (ex. `float4`: 4)
        #[derive(Clone, Debug, Copy, PartialEq, Eq)]
        pub enum Cardinality {
            One,
            Two,
            Three,
            Four,
            Eight,
            Sixteen,
        }

        /// The type of a kernel argument derived from its string representation.
        #[allow(dead_code)]
        #[derive(Clone, Debug)]
        pub struct ArgType {
            base_type: BaseType,
            cardinality: Cardinality,
            is_ptr: bool,
        }

        impl ArgType {
            /// Returns an `ArgType` that will always return `true` when calling
            /// `::is_match`.
            pub fn unknown() -> OclCoreResult<ArgType> {
                Ok(ArgType {
                    base_type: BaseType::Unknown,
                    cardinality: Cardinality::One,
                    is_ptr: false,
                })
            }

            /// Ascertains a `KernelArgType` from the contents of a
            /// `KernelArgInfoResult::TypeName`.
            ///
            /// * TODO: Optimize or outsource this if possible. Is `::contains`
            /// the fastest way to parse these in this situation? Should
            /// `::starts_with` be used for base type names instead?
            pub fn from_str(type_name: &str) -> OclCoreResult<ArgType> {
                let is_ptr = type_name.contains("*");

                let card = if type_name.contains("16") {
                    Cardinality::Sixteen
                } else if type_name.contains("8") {
                    Cardinality::Eight
                } else if type_name.contains("4") {
                    Cardinality::Four
                } else if type_name.contains("3") {
                    Cardinality::Three
                } else if type_name.contains("2") {
                    Cardinality::Two
                } else {
                    Cardinality::One
                };

                let base = if type_name.contains("uchar") {
                    BaseType::Uchar
                } else if type_name.contains("char") {
                    BaseType::Char
                } else if type_name.contains("ushort") {
                    BaseType::Ushort
                } else if type_name.contains("short") {
                    BaseType::Short
                } else if type_name.contains("uint") {
                    BaseType::Uint
                } else if type_name.contains("int") {
                    BaseType::Int
                } else if type_name.contains("ulong") {
                    BaseType::Ulong
                } else if type_name.contains("long") {
                    BaseType::Long
                } else if type_name.contains("float") {
                    BaseType::Float
                } else if type_name.contains("double") {
                    BaseType::Double
                } else if type_name.contains("sampler") {
                    BaseType::Sampler
                } else if type_name.contains("image") {
                    BaseType::Image
                } else {
                    BaseType::Unknown
                };

                Ok(ArgType {
                    base_type: base,
                    cardinality: card,
                    is_ptr: is_ptr,
                })
            }

            /// Returns a new argument type specifier.
            ///
            /// This function calls `core::get_kernel_arg_info`. Some platforms
            /// (Apple, NVIDIA) either do not implement
            /// `core::get_kernel_arg_info` or error in irregular ways. Known
            /// irregular errors are checked for here. The result of a call to
            /// `ArgType::unknown()` (which matches any argument type) is returned
            /// if any are found.
            pub fn from_kern_and_idx(core: &KernelCore, arg_idx: u32) -> OclCoreResult<ArgType> {
                use core::EmptyInfoResultError;
                use core::ErrorKind as OclCoreErrorKind;

                match arg_type_name(core, arg_idx) {
                    Ok(type_name) => ArgType::from_str(type_name.as_str()),
                    Err(err) => {
                        // Escape hatches for known, platform-specific errors.
                        match *err.kind() {
                            OclCoreErrorKind::Api(ref api_err) => {
                                if api_err.status() == Status::CL_KERNEL_ARG_INFO_NOT_AVAILABLE {
                                    return ArgType::unknown();
                                }
                            }
                            OclCoreErrorKind::EmptyInfoResult(EmptyInfoResultError::KernelArg) => {
                                return ArgType::unknown();
                            },
                            _ => (),
                        }

                        Err(err)
                    },
                }
            }

            /// Returns true if `type_id` matches the base type of this `ArgType`.
            pub fn matches(&self, type_id: TypeId) -> bool {
                match self.base_type {
                    BaseType::Char => {
                        let card_match = match self.cardinality {
                            Cardinality::One => TypeId::of::<cl_char>() == type_id,
                            Cardinality::Two => TypeId::of::<Char2>() == type_id,
                            Cardinality::Three => TypeId::of::<Char3>() == type_id,
                            Cardinality::Four => TypeId::of::<Char4>() == type_id,
                            Cardinality::Eight => TypeId::of::<Char8>() == type_id,
                            Cardinality::Sixteen => TypeId::of::<Char16>() == type_id,
                        };

                        (self.is_ptr && (TypeId::of::<cl_char>() == type_id || card_match)) ||
                            (!self.is_ptr && card_match)
                    },
                    BaseType::Uchar => {
                        let card_match = match self.cardinality {
                            Cardinality::One => TypeId::of::<cl_uchar>() == type_id,
                            Cardinality::Two => TypeId::of::<Uchar2>() == type_id,
                            Cardinality::Three => TypeId::of::<Uchar3>() == type_id,
                            Cardinality::Four => TypeId::of::<Uchar4>() == type_id,
                            Cardinality::Eight => TypeId::of::<Uchar8>() == type_id,
                            Cardinality::Sixteen => TypeId::of::<Uchar16>() == type_id,
                        };

                        (self.is_ptr && (TypeId::of::<cl_uchar>() == type_id || card_match)) ||
                            (!self.is_ptr && card_match)
                    },
                    BaseType::Short => {
                        let card_match = match self.cardinality {
                            Cardinality::One => TypeId::of::<cl_short>() == type_id,
                            Cardinality::Two => TypeId::of::<Short2>() == type_id,
                            Cardinality::Three => TypeId::of::<Short3>() == type_id,
                            Cardinality::Four => TypeId::of::<Short4>() == type_id,
                            Cardinality::Eight => TypeId::of::<Short8>() == type_id,
                            Cardinality::Sixteen => TypeId::of::<Short16>() == type_id,
                        };

                        (self.is_ptr && (TypeId::of::<cl_short>() == type_id || card_match)) ||
                            (!self.is_ptr && card_match)
                    },
                    BaseType::Ushort => {
                        let card_match = match self.cardinality {
                            Cardinality::One => TypeId::of::<cl_ushort>() == type_id,
                            Cardinality::Two => TypeId::of::<Ushort2>() == type_id,
                            Cardinality::Three => TypeId::of::<Ushort3>() == type_id,
                            Cardinality::Four => TypeId::of::<Ushort4>() == type_id,
                            Cardinality::Eight => TypeId::of::<Ushort8>() == type_id,
                            Cardinality::Sixteen => TypeId::of::<Ushort16>() == type_id,
                        };

                        (self.is_ptr && (TypeId::of::<cl_ushort>() == type_id || card_match)) ||
                            (!self.is_ptr && card_match)
                    },
                    BaseType::Int => {
                        let card_match = match self.cardinality {
                            Cardinality::One => TypeId::of::<cl_int>() == type_id,
                            Cardinality::Two => TypeId::of::<Int2>() == type_id,
                            Cardinality::Three => TypeId::of::<Int3>() == type_id,
                            Cardinality::Four => TypeId::of::<Int4>() == type_id,
                            Cardinality::Eight => TypeId::of::<Int8>() == type_id,
                            Cardinality::Sixteen => TypeId::of::<Int16>() == type_id,
                        };

                        (self.is_ptr && (TypeId::of::<cl_int>() == type_id || card_match)) ||
                            (!self.is_ptr && card_match)
                    },
                    BaseType::Uint => {
                        let card_match = match self.cardinality {
                            Cardinality::One => TypeId::of::<cl_uint>() == type_id,
                            Cardinality::Two => TypeId::of::<Uint2>() == type_id,
                            Cardinality::Three => TypeId::of::<Uint3>() == type_id,
                            Cardinality::Four => TypeId::of::<Uint4>() == type_id,
                            Cardinality::Eight => TypeId::of::<Uint8>() == type_id,
                            Cardinality::Sixteen => TypeId::of::<Uint16>() == type_id,
                        };

                        (self.is_ptr && (TypeId::of::<cl_uint>() == type_id || card_match)) ||
                            (!self.is_ptr && card_match)
                    },
                    BaseType::Long => {
                        let card_match = match self.cardinality {
                            Cardinality::One => TypeId::of::<cl_long>() == type_id,
                            Cardinality::Two => TypeId::of::<Long2>() == type_id,
                            Cardinality::Three => TypeId::of::<Long3>() == type_id,
                            Cardinality::Four => TypeId::of::<Long4>() == type_id,
                            Cardinality::Eight => TypeId::of::<Long8>() == type_id,
                            Cardinality::Sixteen => TypeId::of::<Long16>() == type_id,
                        };

                        (self.is_ptr && (TypeId::of::<cl_long>() == type_id || card_match)) ||
                            (!self.is_ptr && card_match)
                    },
                    BaseType::Ulong => {
                        let card_match = match self.cardinality {
                            Cardinality::One => TypeId::of::<cl_ulong>() == type_id,
                            Cardinality::Two => TypeId::of::<Ulong2>() == type_id,
                            Cardinality::Three => TypeId::of::<Ulong3>() == type_id,
                            Cardinality::Four => TypeId::of::<Ulong4>() == type_id,
                            Cardinality::Eight => TypeId::of::<Ulong8>() == type_id,
                            Cardinality::Sixteen => TypeId::of::<Ulong16>() == type_id,
                        };

                        (self.is_ptr && (TypeId::of::<cl_ulong>() == type_id || card_match)) ||
                            (!self.is_ptr && card_match)
                    },
                    BaseType::Float => {
                        let card_match = match self.cardinality {
                            Cardinality::One => TypeId::of::<cl_float>() == type_id,
                            Cardinality::Two => TypeId::of::<Float2>() == type_id,
                            Cardinality::Three => TypeId::of::<Float3>() == type_id,
                            Cardinality::Four => TypeId::of::<Float4>() == type_id,
                            Cardinality::Eight => TypeId::of::<Float8>() == type_id,
                            Cardinality::Sixteen => TypeId::of::<Float16>() == type_id,
                        };

                        (self.is_ptr && (TypeId::of::<cl_float>() == type_id || card_match)) ||
                            (!self.is_ptr && card_match)
                    },
                    BaseType::Double => {
                        let card_match = match self.cardinality {
                            Cardinality::One => TypeId::of::<cl_double>() == type_id,
                            Cardinality::Two => TypeId::of::<Double2>() == type_id,
                            Cardinality::Three => TypeId::of::<Double3>() == type_id,
                            Cardinality::Four => TypeId::of::<Double4>() == type_id,
                            Cardinality::Eight => TypeId::of::<Double8>() == type_id,
                            Cardinality::Sixteen => TypeId::of::<Double16>() == type_id,
                        };

                        (self.is_ptr && (TypeId::of::<cl_double>() == type_id || card_match)) ||
                            (!self.is_ptr && card_match)
                    },
                    BaseType::Sampler => TypeId::of::<u64>() == type_id,
                    BaseType::Image => TypeId::of::<u64>() == type_id,
                    // Everything matches if type was undetermined (escape hatch):
                    BaseType::Unknown => true,
                }
            }

            /// Returns true if the type of `T` matches the base type of this `ArgType`.
            pub fn is_match<T: OclPrm + Any + 'static>(&self) -> bool {
                self.matches(TypeId::of::<T>())
            }

            #[allow(dead_code)]
            pub fn is_ptr(&self) -> bool {
                self.is_ptr
            }

            pub fn is_unknown(&self) -> bool {
                match self.base_type {
                    BaseType::Unknown => true,
                    _ => false,
                }
            }
        }

        impl<'a> From<&'a str> for ArgType {
            /// Ascertains a `KernelArgType` from the contents of a
            /// `KernelArgInfoResult::TypeName`.
            ///
            /// Panics if the string is not valid.
            fn from(type_name: &'a str) -> ArgType {
                ArgType::from_str(type_name).unwrap()
            }
        }
    }

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