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- <#@ template debug="false" hostspecific="false" language="C#" #>
- <#@ assembly name="System.Core" #>
- <#@ import namespace="System.Linq" #>
- <#@ import namespace="System.Text" #>
- <#@ import namespace="System.Collections.Generic" #>
- <#@ output extension=".cs" #>
- // Licensed to the .NET Foundation under one or more agreements.
- // The .NET Foundation licenses this file to you under the MIT license.
- // See the LICENSE file in the project root for more information.
- using System.Collections.Generic;
- using System.Threading;
- using System.Threading.Tasks;
- namespace System.Linq
- {
- public static partial class AsyncEnumerable
- {
- <#
- foreach (var m in new[] { "Max", "Min" })
- {
- var comparison = m == "Max" ? ">" : "<";
- foreach (var t in new[] { "int", "int?", "long", "long?", "float", "float?", "double", "double?", "decimal", "decimal?" })
- {
- var isFloatingPoint = t.StartsWith("float") || t.StartsWith("double");
- var isInteger = t.StartsWith("int") || t.StartsWith("long");
- var isNullable = t.EndsWith("?");
- var shortCircuit = t.StartsWith("decimal");
- #>
- public static Task<<#=t#>> <#=m#>Async(this IAsyncEnumerable<<#=t#>> source, CancellationToken cancellationToken = default)
- {
- if (source == null)
- throw Error.ArgumentNull(nameof(source));
- return Core(source, cancellationToken);
- static async Task<<#=t#>> Core(IAsyncEnumerable<<#=t#>> _source, CancellationToken _cancellationToken)
- {
- <#
- if (!isNullable)
- {
- #>
- <#=t#> value;
- #if CSHARP8
- await using (var e = _source.GetAsyncEnumerator(_cancellationToken).ConfigureAwait(false))
- {
- if (!await e.MoveNextAsync())
- {
- throw Error.NoElements();
- }
- value = e.Current;
- <#
- if (isFloatingPoint && m == "Max")
- {
- #>
- // NaN is ordered less than all other values. We need to do explicit checks
- // to ensure this, but once we've found a value that is not NaN we need no
- // longer worry about it, so first loop until such a value is found (or not,
- // as the case may be).
- while (<#=t#>.IsNaN(value))
- {
- if (!await e.MoveNextAsync())
- {
- return value;
- }
- value = e.Current;
- }
- <#
- }
- #>
- while (await e.MoveNextAsync())
- {
- var x = e.Current;
- if (x <#=comparison#> value)
- {
- value = x;
- }
- <#
- if (isFloatingPoint && m == "Min")
- {
- #>
- else
- {
- // Normally NaN < anything is false, as is anything < NaN
- // However, this leads to some irksome outcomes in Min and Max.
- // If we use those semantics then Min(NaN, 5.0) is NaN, but
- // Min(5.0, NaN) is 5.0! To fix this, we impose a total
- // ordering where NaN is smaller than every value, including
- // negative infinity.
- // Not testing for NaN therefore isn't an option, but since we
- // can't find a smaller value, we can short-circuit.
- if (<#=t#>.IsNaN(x))
- {
- return x;
- }
- }
- <#
- }
- #>
- }
- }
- #else
- var e = _source.GetAsyncEnumerator(_cancellationToken);
- try
- {
- if (!await e.MoveNextAsync().ConfigureAwait(false))
- {
- throw Error.NoElements();
- }
- value = e.Current;
- <#
- if (isFloatingPoint && m == "Max")
- {
- #>
- // NaN is ordered less than all other values. We need to do explicit checks
- // to ensure this, but once we've found a value that is not NaN we need no
- // longer worry about it, so first loop until such a value is found (or not,
- // as the case may be).
- while (<#=t#>.IsNaN(value))
- {
- if (!await e.MoveNextAsync().ConfigureAwait(false))
- {
- return value;
- }
- value = e.Current;
- }
- <#
- }
- #>
- while (await e.MoveNextAsync().ConfigureAwait(false))
- {
- var x = e.Current;
- if (x <#=comparison#> value)
- {
- value = x;
- }
- <#
- if (isFloatingPoint && m == "Min")
- {
- #>
- else
- {
- // Normally NaN < anything is false, as is anything < NaN
- // However, this leads to some irksome outcomes in Min and Max.
- // If we use those semantics then Min(NaN, 5.0) is NaN, but
- // Min(5.0, NaN) is 5.0! To fix this, we impose a total
- // ordering where NaN is smaller than every value, including
- // negative infinity.
- // Not testing for NaN therefore isn't an option, but since we
- // can't find a smaller value, we can short-circuit.
- if (<#=t#>.IsNaN(x))
- {
- return x;
- }
- }
- <#
- }
- #>
- }
- }
- finally
- {
- await e.DisposeAsync().ConfigureAwait(false);
- }
- #endif
- return value;
- <#
- }
- else
- {
- #>
- <#=t#> value = null;
- #if CSHARP8
- await using (var e = _source.GetAsyncEnumerator(_cancellationToken).ConfigureAwait(false))
- {
- // Start off knowing that we've a non-null value (or exit here, knowing we don't)
- // so we don't have to keep testing for nullity.
- do
- {
- if (!await e.MoveNextAsync())
- {
- return value;
- }
- value = e.Current;
- }
- while (!value.HasValue);
- // Keep hold of the wrapped value, and do comparisons on that, rather than
- // using the lifted operation each time.
- var valueVal = value.GetValueOrDefault();
- <#
- if (isInteger && m == "Max")
- {
- #>
- if (valueVal >= 0)
- {
- // We can fast-path this case where we know HasValue will
- // never affect the outcome, without constantly checking
- // if we're in such a state. Similar fast-paths could
- // be done for other cases, but as all-positive or mostly-
- // positive integer values are quite common in real-world
- // uses, it's only been done for int? and long?.
- while (await e.MoveNextAsync())
- {
- var cur = e.Current;
- var x = cur.GetValueOrDefault();
- if (x <#=comparison#> valueVal)
- {
- valueVal = x;
- value = cur;
- }
- }
- }
- else
- {
- while (await e.MoveNextAsync())
- {
- var cur = e.Current;
- var x = cur.GetValueOrDefault();
- // Do not replace & with &&. The branch prediction cost outweighs the extra operation
- // unless nulls either never happen or always happen.
- if (cur.HasValue & x <#=comparison#> valueVal)
- {
- valueVal = x;
- value = cur;
- }
- }
- }
- <#
- }
- else if (isFloatingPoint && m == "Min")
- {
- #>
- while (await e.MoveNextAsync())
- {
- var cur = e.Current;
- if (cur.HasValue)
- {
- var x = cur.GetValueOrDefault();
- if (x <#=comparison#> valueVal)
- {
- valueVal = x;
- value = cur;
- }
- else
- {
- // Normally NaN < anything is false, as is anything < NaN
- // However, this leads to some irksome outcomes in Min and Max.
- // If we use those semantics then Min(NaN, 5.0) is NaN, but
- // Min(5.0, NaN) is 5.0! To fix this, we impose a total
- // ordering where NaN is smaller than every value, including
- // negative infinity.
- // Not testing for NaN therefore isn't an option, but since we
- // can't find a smaller value, we can short-circuit.
- if (<#=t.TrimEnd('?')#>.IsNaN(x))
- {
- return cur;
- }
- }
- }
- }
- <#
- }
- else
- {
- if (isFloatingPoint && m == "Max")
- {
- #>
- // NaN is ordered less than all other values. We need to do explicit checks
- // to ensure this, but once we've found a value that is not NaN we need no
- // longer worry about it, so first loop until such a value is found (or not,
- // as the case may be).
- while (<#=t.TrimEnd('?')#>.IsNaN(valueVal))
- {
- if (!await e.MoveNextAsync())
- {
- return value;
- }
- var cur = e.Current;
- if (cur.HasValue)
- {
- valueVal = (value = cur).GetValueOrDefault();
- }
- }
- <#
- }
- #>
- while (await e.MoveNextAsync())
- {
- var cur = e.Current;
- var x = cur.GetValueOrDefault();
- <#
- if (shortCircuit)
- {
- #>
- if (cur.HasValue && x <#=comparison#> valueVal)
- <#
- }
- else
- {
- #>
- // Do not replace & with &&. The branch prediction cost outweighs the extra operation
- // unless nulls either never happen or always happen.
- if (cur.HasValue & x <#=comparison#> valueVal)
- <#
- }
- #>
- {
- valueVal = x;
- value = cur;
- }
- }
- <#
- }
- #>
- }
- #else
- var e = _source.GetAsyncEnumerator(_cancellationToken);
- try
- {
- // Start off knowing that we've a non-null value (or exit here, knowing we don't)
- // so we don't have to keep testing for nullity.
- do
- {
- if (!await e.MoveNextAsync().ConfigureAwait(false))
- {
- return value;
- }
- value = e.Current;
- }
- while (!value.HasValue);
- // Keep hold of the wrapped value, and do comparisons on that, rather than
- // using the lifted operation each time.
- var valueVal = value.GetValueOrDefault();
- <#
- if (isInteger && m == "Max")
- {
- #>
- if (valueVal >= 0)
- {
- // We can fast-path this case where we know HasValue will
- // never affect the outcome, without constantly checking
- // if we're in such a state. Similar fast-paths could
- // be done for other cases, but as all-positive or mostly-
- // positive integer values are quite common in real-world
- // uses, it's only been done for int? and long?.
- while (await e.MoveNextAsync().ConfigureAwait(false))
- {
- var cur = e.Current;
- var x = cur.GetValueOrDefault();
- if (x <#=comparison#> valueVal)
- {
- valueVal = x;
- value = cur;
- }
- }
- }
- else
- {
- while (await e.MoveNextAsync().ConfigureAwait(false))
- {
- var cur = e.Current;
- var x = cur.GetValueOrDefault();
- // Do not replace & with &&. The branch prediction cost outweighs the extra operation
- // unless nulls either never happen or always happen.
- if (cur.HasValue & x <#=comparison#> valueVal)
- {
- valueVal = x;
- value = cur;
- }
- }
- }
- <#
- }
- else if (isFloatingPoint && m == "Min")
- {
- #>
- while (await e.MoveNextAsync().ConfigureAwait(false))
- {
- var cur = e.Current;
- if (cur.HasValue)
- {
- var x = cur.GetValueOrDefault();
- if (x <#=comparison#> valueVal)
- {
- valueVal = x;
- value = cur;
- }
- else
- {
- // Normally NaN < anything is false, as is anything < NaN
- // However, this leads to some irksome outcomes in Min and Max.
- // If we use those semantics then Min(NaN, 5.0) is NaN, but
- // Min(5.0, NaN) is 5.0! To fix this, we impose a total
- // ordering where NaN is smaller than every value, including
- // negative infinity.
- // Not testing for NaN therefore isn't an option, but since we
- // can't find a smaller value, we can short-circuit.
- if (<#=t.TrimEnd('?')#>.IsNaN(x))
- {
- return cur;
- }
- }
- }
- }
- <#
- }
- else
- {
- if (isFloatingPoint && m == "Max")
- {
- #>
- // NaN is ordered less than all other values. We need to do explicit checks
- // to ensure this, but once we've found a value that is not NaN we need no
- // longer worry about it, so first loop until such a value is found (or not,
- // as the case may be).
- while (<#=t.TrimEnd('?')#>.IsNaN(valueVal))
- {
- if (!await e.MoveNextAsync().ConfigureAwait(false))
- {
- return value;
- }
- var cur = e.Current;
- if (cur.HasValue)
- {
- valueVal = (value = cur).GetValueOrDefault();
- }
- }
- <#
- }
- #>
- while (await e.MoveNextAsync().ConfigureAwait(false))
- {
- var cur = e.Current;
- var x = cur.GetValueOrDefault();
- <#
- if (shortCircuit)
- {
- #>
- if (cur.HasValue && x <#=comparison#> valueVal)
- <#
- }
- else
- {
- #>
- // Do not replace & with &&. The branch prediction cost outweighs the extra operation
- // unless nulls either never happen or always happen.
- if (cur.HasValue & x <#=comparison#> valueVal)
- <#
- }
- #>
- {
- valueVal = x;
- value = cur;
- }
- }
- <#
- }
- #>
- }
- finally
- {
- await e.DisposeAsync().ConfigureAwait(false);
- }
- #endif
- return value;
- <#
- }
- #>
- }
- }
- <#
- foreach (var overload in new[] {
- new { selector = "Func<TSource, " + t + ">", invoke = "_selector(e.Current)" },
- new { selector = "Func<TSource, ValueTask<" + t + ">>", invoke = "await _selector(e.Current).ConfigureAwait(false)" },
- new { selector = "Func<TSource, CancellationToken, ValueTask<" + t + ">>", invoke = "await _selector(e.Current, _cancellationToken).ConfigureAwait(false)" },
- })
- {
- var isDeepCancellation = overload.selector.Contains("CancellationToken");
- if (isDeepCancellation)
- {
- #>
- #if !NO_DEEP_CANCELLATION
- <#
- }
- #>
- public static Task<<#=t#>> <#=m#>Async<TSource>(this IAsyncEnumerable<TSource> source, <#=overload.selector#> selector, CancellationToken cancellationToken = default)
- {
- if (source == null)
- throw Error.ArgumentNull(nameof(source));
- if (selector == null)
- throw Error.ArgumentNull(nameof(selector));
- return Core(source, selector, cancellationToken);
- static async Task<<#=t#>> Core(IAsyncEnumerable<TSource> _source, <#=overload.selector#> _selector, CancellationToken _cancellationToken)
- {
- <#
- if (!isNullable)
- {
- #>
- <#=t#> value;
- #if CSHARP8
- await using (var e = _source.GetAsyncEnumerator(_cancellationToken).ConfigureAwait(false))
- {
- if (!await e.MoveNextAsync())
- {
- throw Error.NoElements();
- }
- value = <#=overload.invoke#>;
- <#
- if (isFloatingPoint && m == "Max")
- {
- #>
- // NaN is ordered less than all other values. We need to do explicit checks
- // to ensure this, but once we've found a value that is not NaN we need no
- // longer worry about it, so first loop until such a value is found (or not,
- // as the case may be).
- while (<#=t#>.IsNaN(value))
- {
- if (!await e.MoveNextAsync())
- {
- return value;
- }
- value = <#=overload.invoke#>;
- }
- <#
- }
- #>
- while (await e.MoveNextAsync())
- {
- var x = <#=overload.invoke#>;
- if (x <#=comparison#> value)
- {
- value = x;
- }
- <#
- if (isFloatingPoint && m == "Min")
- {
- #>
- else
- {
- // Normally NaN < anything is false, as is anything < NaN
- // However, this leads to some irksome outcomes in Min and Max.
- // If we use those semantics then Min(NaN, 5.0) is NaN, but
- // Min(5.0, NaN) is 5.0! To fix this, we impose a total
- // ordering where NaN is smaller than every value, including
- // negative infinity.
- // Not testing for NaN therefore isn't an option, but since we
- // can't find a smaller value, we can short-circuit.
- if (<#=t#>.IsNaN(x))
- {
- return x;
- }
- }
- <#
- }
- #>
- }
- }
- #else
- var e = _source.GetAsyncEnumerator(_cancellationToken);
- try
- {
- if (!await e.MoveNextAsync().ConfigureAwait(false))
- {
- throw Error.NoElements();
- }
- value = <#=overload.invoke#>;
- <#
- if (isFloatingPoint && m == "Max")
- {
- #>
- // NaN is ordered less than all other values. We need to do explicit checks
- // to ensure this, but once we've found a value that is not NaN we need no
- // longer worry about it, so first loop until such a value is found (or not,
- // as the case may be).
- while (<#=t#>.IsNaN(value))
- {
- if (!await e.MoveNextAsync().ConfigureAwait(false))
- {
- return value;
- }
- value = <#=overload.invoke#>;
- }
- <#
- }
- #>
- while (await e.MoveNextAsync().ConfigureAwait(false))
- {
- var x = <#=overload.invoke#>;
- if (x <#=comparison#> value)
- {
- value = x;
- }
- <#
- if (isFloatingPoint && m == "Min")
- {
- #>
- else
- {
- // Normally NaN < anything is false, as is anything < NaN
- // However, this leads to some irksome outcomes in Min and Max.
- // If we use those semantics then Min(NaN, 5.0) is NaN, but
- // Min(5.0, NaN) is 5.0! To fix this, we impose a total
- // ordering where NaN is smaller than every value, including
- // negative infinity.
- // Not testing for NaN therefore isn't an option, but since we
- // can't find a smaller value, we can short-circuit.
- if (<#=t#>.IsNaN(x))
- {
- return x;
- }
- }
- <#
- }
- #>
- }
- }
- finally
- {
- await e.DisposeAsync().ConfigureAwait(false);
- }
- #endif
- return value;
- <#
- }
- else
- {
- #>
- <#=t#> value = null;
- #if CSHARP8
- await using (var e = _source.GetAsyncEnumerator(_cancellationToken).ConfigureAwait(false))
- {
- // Start off knowing that we've a non-null value (or exit here, knowing we don't)
- // so we don't have to keep testing for nullity.
- do
- {
- if (!await e.MoveNextAsync())
- {
- return value;
- }
- value = <#=overload.invoke#>;
- }
- while (!value.HasValue);
- // Keep hold of the wrapped value, and do comparisons on that, rather than
- // using the lifted operation each time.
- var valueVal = value.GetValueOrDefault();
- <#
- if (isInteger && m == "Max")
- {
- #>
- if (valueVal >= 0)
- {
- // We can fast-path this case where we know HasValue will
- // never affect the outcome, without constantly checking
- // if we're in such a state. Similar fast-paths could
- // be done for other cases, but as all-positive or mostly-
- // positive integer values are quite common in real-world
- // uses, it's only been done for int? and long?.
- while (await e.MoveNextAsync())
- {
- var cur = <#=overload.invoke#>;
- var x = cur.GetValueOrDefault();
- if (x <#=comparison#> valueVal)
- {
- valueVal = x;
- value = cur;
- }
- }
- }
- else
- {
- while (await e.MoveNextAsync())
- {
- var cur = <#=overload.invoke#>;
- var x = cur.GetValueOrDefault();
- // Do not replace & with &&. The branch prediction cost outweighs the extra operation
- // unless nulls either never happen or always happen.
- if (cur.HasValue & x <#=comparison#> valueVal)
- {
- valueVal = x;
- value = cur;
- }
- }
- }
- <#
- }
- else if (isFloatingPoint && m == "Min")
- {
- #>
- while (await e.MoveNextAsync())
- {
- var cur = <#=overload.invoke#>;
- if (cur.HasValue)
- {
- var x = cur.GetValueOrDefault();
- if (x <#=comparison#> valueVal)
- {
- valueVal = x;
- value = cur;
- }
- else
- {
- // Normally NaN < anything is false, as is anything < NaN
- // However, this leads to some irksome outcomes in Min and Max.
- // If we use those semantics then Min(NaN, 5.0) is NaN, but
- // Min(5.0, NaN) is 5.0! To fix this, we impose a total
- // ordering where NaN is smaller than every value, including
- // negative infinity.
- // Not testing for NaN therefore isn't an option, but since we
- // can't find a smaller value, we can short-circuit.
- if (<#=t.TrimEnd('?')#>.IsNaN(x))
- {
- return cur;
- }
- }
- }
- }
- <#
- }
- else
- {
- if (isFloatingPoint && m == "Max")
- {
- #>
- // NaN is ordered less than all other values. We need to do explicit checks
- // to ensure this, but once we've found a value that is not NaN we need no
- // longer worry about it, so first loop until such a value is found (or not,
- // as the case may be).
- while (<#=t.TrimEnd('?')#>.IsNaN(valueVal))
- {
- if (!await e.MoveNextAsync())
- {
- return value;
- }
- var cur = <#=overload.invoke#>;
- if (cur.HasValue)
- {
- valueVal = (value = cur).GetValueOrDefault();
- }
- }
- <#
- }
- #>
- while (await e.MoveNextAsync())
- {
- var cur = <#=overload.invoke#>;
- var x = cur.GetValueOrDefault();
- <#
- if (shortCircuit)
- {
- #>
- if (cur.HasValue && x <#=comparison#> valueVal)
- <#
- }
- else
- {
- #>
- // Do not replace & with &&. The branch prediction cost outweighs the extra operation
- // unless nulls either never happen or always happen.
- if (cur.HasValue & x <#=comparison#> valueVal)
- <#
- }
- #>
- {
- valueVal = x;
- value = cur;
- }
- }
- <#
- }
- #>
- }
- #else
- var e = _source.GetAsyncEnumerator(_cancellationToken);
- try
- {
- // Start off knowing that we've a non-null value (or exit here, knowing we don't)
- // so we don't have to keep testing for nullity.
- do
- {
- if (!await e.MoveNextAsync().ConfigureAwait(false))
- {
- return value;
- }
- value = <#=overload.invoke#>;
- }
- while (!value.HasValue);
- // Keep hold of the wrapped value, and do comparisons on that, rather than
- // using the lifted operation each time.
- var valueVal = value.GetValueOrDefault();
- <#
- if (isInteger && m == "Max")
- {
- #>
- if (valueVal >= 0)
- {
- // We can fast-path this case where we know HasValue will
- // never affect the outcome, without constantly checking
- // if we're in such a state. Similar fast-paths could
- // be done for other cases, but as all-positive or mostly-
- // positive integer values are quite common in real-world
- // uses, it's only been done for int? and long?.
- while (await e.MoveNextAsync().ConfigureAwait(false))
- {
- var cur = <#=overload.invoke#>;
- var x = cur.GetValueOrDefault();
- if (x <#=comparison#> valueVal)
- {
- valueVal = x;
- value = cur;
- }
- }
- }
- else
- {
- while (await e.MoveNextAsync().ConfigureAwait(false))
- {
- var cur = <#=overload.invoke#>;
- var x = cur.GetValueOrDefault();
- // Do not replace & with &&. The branch prediction cost outweighs the extra operation
- // unless nulls either never happen or always happen.
- if (cur.HasValue & x <#=comparison#> valueVal)
- {
- valueVal = x;
- value = cur;
- }
- }
- }
- <#
- }
- else if (isFloatingPoint && m == "Min")
- {
- #>
- while (await e.MoveNextAsync().ConfigureAwait(false))
- {
- var cur = <#=overload.invoke#>;
- if (cur.HasValue)
- {
- var x = cur.GetValueOrDefault();
- if (x <#=comparison#> valueVal)
- {
- valueVal = x;
- value = cur;
- }
- else
- {
- // Normally NaN < anything is false, as is anything < NaN
- // However, this leads to some irksome outcomes in Min and Max.
- // If we use those semantics then Min(NaN, 5.0) is NaN, but
- // Min(5.0, NaN) is 5.0! To fix this, we impose a total
- // ordering where NaN is smaller than every value, including
- // negative infinity.
- // Not testing for NaN therefore isn't an option, but since we
- // can't find a smaller value, we can short-circuit.
- if (<#=t.TrimEnd('?')#>.IsNaN(x))
- {
- return cur;
- }
- }
- }
- }
- <#
- }
- else
- {
- if (isFloatingPoint && m == "Max")
- {
- #>
- // NaN is ordered less than all other values. We need to do explicit checks
- // to ensure this, but once we've found a value that is not NaN we need no
- // longer worry about it, so first loop until such a value is found (or not,
- // as the case may be).
- while (<#=t.TrimEnd('?')#>.IsNaN(valueVal))
- {
- if (!await e.MoveNextAsync().ConfigureAwait(false))
- {
- return value;
- }
- var cur = <#=overload.invoke#>;
- if (cur.HasValue)
- {
- valueVal = (value = cur).GetValueOrDefault();
- }
- }
- <#
- }
- #>
- while (await e.MoveNextAsync().ConfigureAwait(false))
- {
- var cur = <#=overload.invoke#>;
- var x = cur.GetValueOrDefault();
- <#
- if (shortCircuit)
- {
- #>
- if (cur.HasValue && x <#=comparison#> valueVal)
- <#
- }
- else
- {
- #>
- // Do not replace & with &&. The branch prediction cost outweighs the extra operation
- // unless nulls either never happen or always happen.
- if (cur.HasValue & x <#=comparison#> valueVal)
- <#
- }
- #>
- {
- valueVal = x;
- value = cur;
- }
- }
- <#
- }
- #>
- }
- finally
- {
- await e.DisposeAsync().ConfigureAwait(false);
- }
- #endif
- return value;
- <#
- }
- #>
- }
- }
- <#
- if (isDeepCancellation)
- {
- #>
- #endif
- <#
- }
- }
- #>
- <#
- }
- }
- #>
- }
- }
|