From 4098e47631a16d829f123897ba0cbd82b735e225 Mon Sep 17 00:00:00 2001
From: xing <fthvgb1>
Date: Mon, 16 Jan 2023 18:28:58 +0800
Subject: [PATCH] =?UTF-8?q?=E5=AE=8C=E5=96=84?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

---
 stream/simpleStream.go      | 92 ++++++++++++++++++++-----------------
 stream/simpleStream_test.go | 18 ++++++++
 2 files changed, 69 insertions(+), 41 deletions(-)

diff --git a/stream/simpleStream.go b/stream/simpleStream.go
index d780f2f..c12a6be 100644
--- a/stream/simpleStream.go
+++ b/stream/simpleStream.go
@@ -6,18 +6,56 @@ import (
 	"github/fthvgb1/wp-go/taskPools"
 )
 
+func SimpleParallelFilterAndMap[R, T any](a SimpleSliceStream[T], fn func(T) (R, bool), c int) SimpleSliceStream[R] {
+	p := taskPools.NewPools(c)
+	var x []R
+	rr := safety.NewSlice(x)
+	for _, t := range a.arr {
+		t := t
+		p.Execute(func() {
+			y, ok := fn(t)
+			if ok {
+				rr.Append(y)
+			}
+		})
+	}
+	p.Wait()
+	return SimpleSliceStream[R]{rr.Load()}
+}
+
+func SimpleStreamFilterAndMap[R, T any](a SimpleSliceStream[T], fn func(T) (R, bool)) SimpleSliceStream[R] {
+	return NewSimpleSliceStream(helper.SliceFilterAndMap(a.arr, fn))
+}
+
+func SimpleParallelMap[R, T any](a SimpleSliceStream[T], fn func(T) R, c int) SimpleSliceStream[R] {
+	p := taskPools.NewPools(c)
+	var x []R
+	rr := safety.NewSlice(x)
+	for _, t := range a.arr {
+		t := t
+		p.Execute(func() {
+			rr.Append(fn(t))
+		})
+	}
+	p.Wait()
+	return SimpleSliceStream[R]{rr.Load()}
+}
+func SimpleStreamMap[R, T any](a SimpleSliceStream[T], fn func(T) R) SimpleSliceStream[R] {
+	return NewSimpleSliceStream(helper.SliceMap(a.arr, fn))
+}
+
 func Reduce[T any, S any](s SimpleSliceStream[S], fn func(S, T) T, init T) (r T) {
 	return helper.SliceReduce(s.arr, fn, init)
 }
 
-type SimpleSliceStream[T any] struct {
-	arr []T
-}
-
 func NewSimpleSliceStream[T any](arr []T) SimpleSliceStream[T] {
 	return SimpleSliceStream[T]{arr: arr}
 }
 
+type SimpleSliceStream[T any] struct {
+	arr []T
+}
+
 func (r SimpleSliceStream[T]) ForEach(fn func(T)) {
 	for _, t := range r.arr {
 		fn(t)
@@ -68,43 +106,7 @@ func (r SimpleSliceStream[T]) ParallelMap(fn func(T) T, c int) SimpleSliceStream
 	p.Wait()
 	return SimpleSliceStream[T]{rr.Load()}
 }
-func SimpleParallelFilterAndMap[R, T any](a SimpleSliceStream[T], fn func(T) (R, bool), c int) SimpleSliceStream[R] {
-	p := taskPools.NewPools(c)
-	var x []R
-	rr := safety.NewSlice(x)
-	for _, t := range a.arr {
-		t := t
-		p.Execute(func() {
-			y, ok := fn(t)
-			if ok {
-				rr.Append(y)
-			}
-		})
-	}
-	p.Wait()
-	return SimpleSliceStream[R]{rr.Load()}
-}
 
-func SimpleStreamFilterAndMap[R, T any](a SimpleSliceStream[T], fn func(T) (R, bool)) SimpleSliceStream[R] {
-	return NewSimpleSliceStream(helper.SliceFilterAndMap(a.arr, fn))
-}
-
-func SimpleParallelMap[R, T any](a SimpleSliceStream[T], fn func(T) R, c int) SimpleSliceStream[R] {
-	p := taskPools.NewPools(c)
-	var x []R
-	rr := safety.NewSlice(x)
-	for _, t := range a.arr {
-		t := t
-		p.Execute(func() {
-			rr.Append(fn(t))
-		})
-	}
-	p.Wait()
-	return SimpleSliceStream[R]{rr.Load()}
-}
-func SimpleStreamMap[R, T any](a SimpleSliceStream[T], fn func(T) R) SimpleSliceStream[R] {
-	return NewSimpleSliceStream(helper.SliceMap(a.arr, fn))
-}
 func (r SimpleSliceStream[T]) Map(fn func(T) T) SimpleSliceStream[T] {
 	r.arr = helper.SliceMap(r.arr, fn)
 	return r
@@ -120,7 +122,15 @@ func (r SimpleSliceStream[T]) Len() int {
 }
 
 func (r SimpleSliceStream[T]) Limit(limit, offset int) SimpleSliceStream[T] {
-	return SimpleSliceStream[T]{r.arr[offset : offset+limit]}
+	l := len(r.arr)
+	if offset >= l {
+		return SimpleSliceStream[T]{}
+	}
+	ll := offset + limit
+	if ll > l {
+		ll = l
+	}
+	return SimpleSliceStream[T]{r.arr[offset:ll]}
 }
 
 func (r SimpleSliceStream[T]) Reverse() SimpleSliceStream[T] {
diff --git a/stream/simpleStream_test.go b/stream/simpleStream_test.go
index 615acb0..5030433 100644
--- a/stream/simpleStream_test.go
+++ b/stream/simpleStream_test.go
@@ -92,6 +92,24 @@ func TestSimpleSliceStream_Limit(t *testing.T) {
 			},
 			want: SimpleSliceStream[int]{helper.RangeSlice(6, 8, 1)},
 		},
+		{
+			name: "t2",
+			r:    s,
+			args: args{
+				limit:  3,
+				offset: 9,
+			},
+			want: SimpleSliceStream[int]{helper.RangeSlice(10, 10, 1)},
+		},
+		{
+			name: "t3",
+			r:    s,
+			args: args{
+				limit:  3,
+				offset: 11,
+			},
+			want: SimpleSliceStream[int]{},
+		},
 	}
 	for _, tt := range tests {
 		t.Run(tt.name, func(t *testing.T) {