once.rs - source

Files

a0_basic_app

a1_vehicle

vehicle

a2_async_sim

vehicle

background.rs main.rs

ab_glyph

ttfp

codepoint_ids.rs err.rs font.rs font_arc.rs glyph.rs lib.rs outlined.rs scale.rs ttfp.rs

ab_glyph_rasterizer

geometry.rs lib.rs raster.rs

adler

adler32

agents

app

app.rs mod.rs update_timer.rs

simulation

mod.rs worker.rs

aho_corasick

packed

teddy

compile.rs mod.rs runtime.rs

api.rs mod.rs pattern.rs rabinkarp.rs vector.rs

ahocorasick.rs automaton.rs buffer.rs byte_frequencies.rs classes.rs dfa.rs error.rs lib.rs nfa.rs prefilter.rs state_id.rs

anyhow

backtrace.rs chain.rs context.rs error.rs fmt.rs kind.rs lib.rs macros.rs ptr.rs wrapper.rs

approx

abs_diff_eq.rs lib.rs macros.rs relative_eq.rs ulps_eq.rs

aquamarine

attrs.rs lib.rs parse.rs

ash

atty

bitflags

bytemuck

contiguous.rs lib.rs offset_of.rs pod.rs transparent.rs zeroable.rs

byteorder

cache_padded

cfg_if

chrono

format

mod.rs parse.rs parsed.rs scan.rs strftime.rs

naive

date.rs datetime.rs internals.rs isoweek.rs time.rs

offset

fixed.rs local.rs mod.rs utc.rs

sys

date.rs datetime.rs div.rs lib.rs round.rs sys.rs

color_quant

crc32fast

specialized

mod.rs pclmulqdq.rs

baseline.rs combine.rs lib.rs table.rs

crossbeam_channel

flavors

array.rs at.rs list.rs mod.rs never.rs tick.rs zero.rs

channel.rs context.rs counter.rs err.rs lib.rs select.rs select_macro.rs utils.rs waker.rs

crossbeam_deque

deque.rs lib.rs

crossbeam_epoch

sync

list.rs mod.rs queue.rs

atomic.rs collector.rs default.rs deferred.rs epoch.rs guard.rs internal.rs lib.rs

crossbeam_utils

atomic

atomic_cell.rs consume.rs mod.rs seq_lock.rs

sync

mod.rs parker.rs sharded_lock.rs wait_group.rs

backoff.rs cache_padded.rs lib.rs thread.rs

deflate

draw2d

camera

mod.rs ortho_camera.rs

geometry

glfw_window

mod.rs window_surface.rs

graphics

ext

mod.rs sampler_factory.rs texture_2d_factory.rs texture_loader.rs

frame

descriptor.rs mod.rs sync.rs

layer

batch.rs layer.rs layer_handle.rs layer_stack.rs mod.rs

pipeline2d

descriptor_sets.rs mod.rs pipeline2d.rs

texture_atlas

atlas_version.rs gpu_atlas.rs mod.rs sampler_handle.rs texture_handle.rs

vertex

vulkan

buffer

cpu_buffer.rs mod.rs static_buffer.rs transfer.rs

command_pool

mod.rs owned_command_pool.rs reusable_command_pool.rs

device

mod.rs physical_device.rs queue.rs queue_family_indices.rs

device_allocator

metrics

console_markdown_report.rs metrics.rs mod.rs

suballocator

mod.rs region.rs suballocator.rs

allocation.rs forced_offset.rs mem_unit.rs mod.rs page_allocator.rs passthrough.rs pool.rs shared_ref.rs size_selector.rs type_index.rs

instance

debug_callback.rs extensions.rs layers.rs mod.rs

swapchain

images.rs mod.rs render_pass.rs selection.rs

texture

mipmap_extent.rs mod.rs texture_image.rs

ffi.rs mod.rs shader_module.rs window_surface.rs

frame_context.rs graphics.rs graphics_commands.rs mod.rs

either

flexi_logger

writers

file_log_writer

builder.rs config.rs state.rs

file_log_writer.rs log_writer.rs

code_examples.rs deferred_now.rs flexi_error.rs flexi_logger.rs formats.rs lib.rs log_specification.rs logger.rs logger_handle.rs parameters.rs primary_writer.rs writers.rs

generic_array

arr.rs functional.rs hex.rs impls.rs iter.rs lib.rs sequence.rs

gif

reader

decoder.rs mod.rs

common.rs encoder.rs lib.rs traits.rs

glfw

ffi

callbacks.rs lib.rs

glfw_sys

glob

image

indoc

error.rs expr.rs lib.rs

itertools

jpeg_decoder

worker

immediate.rs mod.rs multithreaded.rs

decoder.rs error.rs huffman.rs idct.rs lib.rs marker.rs parser.rs upsampler.rs

lazy_static

inline_lazy.rs lib.rs

libc

unix

linux_like

linux

arch

generic

gnu

b64

x86_64

align.rs mod.rs not_x32.rs

align.rs mod.rs

align.rs mod.rs

align.rs mod.rs

fixed_width_ints.rs lib.rs macros.rs

libloading

os

unix

consts.rs mod.rs

changelog.rs error.rs lib.rs util.rs

log

lib.rs macros.rs

matrixmultiply

x86

macros.rs mod.rs

aligned_alloc.rs archparam.rs debugmacros.rs dgemm_kernel.rs gemm.rs kernel.rs lib.rs loopmacros.rs ptr.rs sgemm_kernel.rs threading.rs util.rs

memchr

x86

avx.rs mod.rs sse2.rs

fallback.rs iter.rs lib.rs naive.rs

memoffset

lib.rs offset_of.rs raw_field.rs span_of.rs

miniz_oxide

deflate

buffer.rs core.rs mod.rs stream.rs

inflate

core.rs mod.rs output_buffer.rs stream.rs

lib.rs shared.rs

nalgebra

base

geometry

abstract_rotation.rs dual_quaternion.rs dual_quaternion_construction.rs dual_quaternion_conversion.rs dual_quaternion_ops.rs isometry.rs isometry_alias.rs isometry_construction.rs isometry_conversion.rs isometry_interpolation.rs isometry_ops.rs isometry_simba.rs mod.rs op_macros.rs orthographic.rs perspective.rs point.rs point_alias.rs point_construction.rs point_conversion.rs point_coordinates.rs point_ops.rs point_simba.rs quaternion.rs quaternion_construction.rs quaternion_conversion.rs quaternion_coordinates.rs quaternion_ops.rs quaternion_simba.rs reflection.rs rotation.rs rotation_alias.rs rotation_construction.rs rotation_conversion.rs rotation_interpolation.rs rotation_ops.rs rotation_simba.rs rotation_specialization.rs similarity.rs similarity_alias.rs similarity_construction.rs similarity_conversion.rs similarity_ops.rs similarity_simba.rs swizzle.rs transform.rs transform_alias.rs transform_construction.rs transform_conversion.rs transform_ops.rs transform_simba.rs translation.rs translation_alias.rs translation_construction.rs translation_conversion.rs translation_coordinates.rs translation_ops.rs translation_simba.rs unit_complex.rs unit_complex_construction.rs unit_complex_conversion.rs unit_complex_ops.rs unit_complex_simba.rs

linalg

third_party

num_complex

cast.rs lib.rs pow.rs

num_cpus

lib.rs linux.rs

num_integer

average.rs lib.rs roots.rs

num_iter

num_rational

num_traits

ops

checked.rs inv.rs mod.rs mul_add.rs overflowing.rs saturating.rs wrapping.rs

bounds.rs cast.rs float.rs identities.rs int.rs lib.rs macros.rs pow.rs real.rs sign.rs

owned_ttf_parser

convert.rs lib.rs owned.rs

paste

attr.rs error.rs lib.rs segment.rs

png

decoder

mod.rs stream.rs zlib.rs

chunk.rs common.rs encoder.rs filter.rs lib.rs traits.rs utils.rs

proc_macro2

detection.rs fallback.rs lib.rs marker.rs parse.rs wrapper.rs

proc_macro_error

imp

diagnostic.rs dummy.rs lib.rs macros.rs sealed.rs

proc_macro_error_attr

lib.rs parse.rs settings.rs

quote

ext.rs format.rs ident_fragment.rs lib.rs runtime.rs spanned.rs to_tokens.rs

raw_window_handle

rawpointer

rayon

delegate.rs lib.rs math.rs option.rs par_either.rs prelude.rs private.rs range.rs range_inclusive.rs result.rs split_producer.rs str.rs string.rs vec.rs

rayon_core

compile_fail

mod.rs quicksort_race1.rs quicksort_race2.rs quicksort_race3.rs rc_return.rs rc_upvar.rs scope_join_bad.rs

join

scope

sleep

counters.rs mod.rs

spawn

thread_pool

job.rs latch.rs lib.rs log.rs private.rs registry.rs unwind.rs util.rs

regex

regex_syntax

scoped_threadpool

scopeguard

semver

lib.rs version.rs version_req.rs

semver_parser

common.rs lib.rs range.rs recognize.rs version.rs

serde

de

ignored_any.rs impls.rs mod.rs seed.rs utf8.rs value.rs

private

de.rs doc.rs mod.rs ser.rs size_hint.rs

ser

fmt.rs impls.rs impossible.rs mod.rs

integer128.rs lib.rs macros.rs

serde_derive

internals

ast.rs attr.rs case.rs check.rs ctxt.rs mod.rs receiver.rs respan.rs symbol.rs

bound.rs de.rs dummy.rs fragment.rs lib.rs pretend.rs ser.rs try.rs

simba

scalar

complex.rs field.rs mod.rs real.rs subset.rs

simd

auto_simd_impl.rs mod.rs simd_bool.rs simd_complex.rs simd_option.rs simd_partial_ord.rs simd_real.rs simd_signed.rs simd_value.rs

smawk

lib.rs monge.rs

spin_sleep

lib.rs loop_helper.rs

syn

terminal_size

textwrap

core

core.rs indentation.rs lib.rs splitting.rs

thiserror

aserror.rs display.rs lib.rs

thiserror_impl

ast.rs attr.rs expand.rs fmt.rs lib.rs prop.rs valid.rs

tiff

decoder

ifd.rs mod.rs stream.rs

encoder

colortype.rs mod.rs writer.rs

bytecast.rs error.rs lib.rs tags.rs

time

display.rs duration.rs lib.rs parse.rs sys.rs

triple_buffer

ttf_parser

typenum

array.rs bit.rs int.rs lib.rs marker_traits.rs operator_aliases.rs private.rs type_operators.rs uint.rs

unicode_width

lib.rs tables.rs

unicode_xid

lib.rs tables.rs

unindent

vk_sys

weezl

decode.rs encode.rs error.rs lib.rs

yansi

color.rs docify.rs lib.rs macros.rs paint.rs style.rs windows.rs

use crate::iter::plumbing::*;
use crate::iter::*;

/// Creates a parallel iterator that produces an element exactly once.
///
/// This admits no parallelism on its own, but it could be chained to existing
/// parallel iterators to extend their contents, or otherwise used for any code
/// that deals with generic parallel iterators.
///
/// # Examples
///
/// ```
/// use rayon::prelude::*;
/// use rayon::iter::once;
///
/// let pi = (0..1234).into_par_iter()
///     .chain(once(-1))
///     .chain(1234..10_000);
///
/// assert_eq!(pi.clone().count(), 10_001);
/// assert_eq!(pi.clone().filter(|&x| x < 0).count(), 1);
/// assert_eq!(pi.position_any(|x| x < 0), Some(1234));
/// ```
pub fn once<T: Send>(item: T) -> Once<T> {
    Once { item }
}

/// Iterator adaptor for [the `once()` function](fn.once.html).
#[derive(Clone, Debug)]
pub struct Once<T: Send> {
    item: T,
}

impl<T: Send> ParallelIterator for Once<T> {
    type Item = T;

    fn drive_unindexed<C>(self, consumer: C) -> C::Result
    where
        C: UnindexedConsumer<Self::Item>,
    {
        self.drive(consumer)
    }

    fn opt_len(&self) -> Option<usize> {
        Some(1)
    }
}

impl<T: Send> IndexedParallelIterator for Once<T> {
    fn drive<C>(self, consumer: C) -> C::Result
    where
        C: Consumer<Self::Item>,
    {
        consumer.into_folder().consume(self.item).complete()
    }

    fn len(&self) -> usize {
        1
    }

    fn with_producer<CB>(self, callback: CB) -> CB::Output
    where
        CB: ProducerCallback<Self::Item>,
    {
        // Let `OptionProducer` handle it.
        Some(self.item).into_par_iter().with_producer(callback)
    }
}