Update Go versions we test against, update dependencies. (#5)

Co-authored-by: Aaron Hopkins <ahopkins@ziprecruiter.com>

.github/workflows/go-test.yml

@@ -12,7 +12,7 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        go: ['1.13', '1.14', '1.15', '1.16']
+        go: ['1.15', '1.16', '1.17', '1.18']
 
     steps:
       - uses: actions/setup-go@v2

.github/workflows/go-test.yml~

@@ -0,0 +1,37 @@
+name: go-test
+on:
+  push:
+  pull_request:
+  schedule:
+    - cron: '55 4 20 * *'
+
+jobs:
+
+  test:
+    runs-on: ubuntu-latest
+    strategy:
+      fail-fast: false
+      matrix:
+        go: ['1.14', '1.15', '1.16', '1.17']
+
+    steps:
+      - uses: actions/setup-go@v2
+        with:
+          go-version: ${{ matrix.go }}
+      - uses: actions/checkout@v2
+      - run: go test -v -short -race -coverprofile=profile.cov ./...
+      - name: Send coverage
+        uses: shogo82148/actions-goveralls@v1
+        with:
+          path-to-profile: profile.cov
+          flag-name: Go-${{ matrix.go }}
+          parallel: true
+
+  # notifies that all test jobs are finished.
+  finish:
+    needs: test
+    runs-on: ubuntu-latest
+    steps:
+      - uses: shogo82148/actions-goveralls@v1
+        with:
+          parallel-finished: true

go.mod

@@ -1,11 +1,5 @@
 module github.com/die-net/intervals
 
-go 1.17
+go 1.14
 
-require github.com/stretchr/testify v1.7.0
-
-require (
-	github.com/davecgh/go-spew v1.1.0 // indirect
-	github.com/pmezard/go-difflib v1.0.0 // indirect
-	gopkg.in/yaml.v3 v3.0.0-20200313102051-9f266ea9e77c // indirect
-)
+require github.com/stretchr/testify v1.7.5

go.sum

@@ -1,11 +1,15 @@
-github.com/davecgh/go-spew v1.1.0 h1:ZDRjVQ15GmhC3fiQ8ni8+OwkZQO4DARzQgrnXU1Liz8=
 github.com/davecgh/go-spew v1.1.0/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
+github.com/davecgh/go-spew v1.1.1 h1:vj9j/u1bqnvCEfJOwUhtlOARqs3+rkHYY13jYWTU97c=
+github.com/davecgh/go-spew v1.1.1/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
 github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZbAQM=
 github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
 github.com/stretchr/objx v0.1.0/go.mod h1:HFkY916IF+rwdDfMAkV7OtwuqBVzrE8GR6GFx+wExME=
-github.com/stretchr/testify v1.7.0 h1:nwc3DEeHmmLAfoZucVR881uASk0Mfjw8xYJ99tb5CcY=
-github.com/stretchr/testify v1.7.0/go.mod h1:6Fq8oRcR53rry900zMqJjRRixrwX3KX962/h/Wwjteg=
+github.com/stretchr/objx v0.4.0/go.mod h1:YvHI0jy2hoMjB+UWwv71VJQ9isScKT/TqJzVSSt89Yw=
+github.com/stretchr/testify v1.7.1/go.mod h1:6Fq8oRcR53rry900zMqJjRRixrwX3KX962/h/Wwjteg=
+github.com/stretchr/testify v1.7.5 h1:s5PTfem8p8EbKQOctVV53k6jCJt3UX4IEJzwh+C324Q=
+github.com/stretchr/testify v1.7.5/go.mod h1:yNjHg4UonilssWZ8iaSj1OCr/vHnekPRkoO+kdMU+MU=
 gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405 h1:yhCVgyC4o1eVCa2tZl7eS0r+SDo693bJlVdllGtEeKM=
 gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
-gopkg.in/yaml.v3 v3.0.0-20200313102051-9f266ea9e77c h1:dUUwHk2QECo/6vqA44rthZ8ie2QXMNeKRTHCNY2nXvo=
 gopkg.in/yaml.v3 v3.0.0-20200313102051-9f266ea9e77c/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=
+gopkg.in/yaml.v3 v3.0.1 h1:fxVm/GzAzEWqLHuvctI91KS9hhNmmWOoWu0XTYJS7CA=
+gopkg.in/yaml.v3 v3.0.1/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=

intervals.go

@@ -1,16 +1,20 @@
-// Package intervals provides an insertion-sort based solution to the merge
-// overlapping intervals problem.
+// Package intervals provides a fast insertion-sort based solution to the
+// merge overlapping intervals problem.
 package intervals
 
 import (
 	"sort"
 )
 
+// Interval represents range of the form [Start, End), which contains all
+// integer x in Start <= x < End.
 type Interval struct {
 	Start int64
 	End   int64
 }
 
+// Empty returns true if Start is less than end, false if they are equal,
+// and panics if Start is greater than End.
 func (v Interval) Empty() bool {
 	if v.Start < v.End {
 		return false
@@ -23,8 +27,31 @@ func (v Interval) Empty() bool {
 	return true
 }
 
+// Intervals is an ordered representation of a slice of Interval.
 type Intervals []Interval
 
+// Search will return the Interval in the given Intervals containing the
+// value of off and true if found.  Otherwise, it will return an empty
+// Interval and false.
+func (ivs Intervals) Search(off int64) (Interval, bool) {
+	// Skip search if we definitely don't contain offset.
+	if len(ivs) == 0 || ivs[0].Start > off || ivs[len(ivs)-1].End < off {
+		return Interval{}, false
+	}
+
+	// Find the first interval that matches, whose end is at least off.
+	i := sort.Search(len(ivs), func(i int) bool { return ivs[i].End >= off })
+	if i < len(ivs) && ivs[i].Start <= off {
+		return ivs[i], true
+	}
+
+	return Interval{}, false
+}
+
+// Insert adds a given Interval to Intervals, possibly inserting in the
+// correct order between two intervals, extending an existing interval, or
+// compacting existing intervals as necessary.  ivs must be correctly
+// ordered.  An empty v will result in a noop, and an invalid v may panic.
 func (ivs Intervals) Insert(v Interval) Intervals {
 	if v.Empty() {
 		return ivs

intervals_test.go

@@ -13,7 +13,31 @@ func init() {
 	rand.Seed(time.Now().UnixNano())
 }
 
-func TestExpected(t *testing.T) {
+func TestSearchExpected(t *testing.T) {
+	tests := []struct {
+		intervals Intervals
+		offset    int64
+		expected  Interval
+		ok        bool
+	}{
+		{intervals: Intervals{{0, 2}, {4, 5}}, offset: -1, expected: Interval{0, 0}, ok: false},
+		{intervals: Intervals{{0, 2}, {4, 5}}, offset: 0, expected: Interval{0, 2}, ok: true},
+		{intervals: Intervals{{0, 2}, {4, 5}}, offset: 1, expected: Interval{0, 2}, ok: true},
+		{intervals: Intervals{{0, 2}, {4, 5}}, offset: 2, expected: Interval{0, 2}, ok: true},
+		{intervals: Intervals{{0, 2}, {4, 5}}, offset: 3, expected: Interval{0, 0}, ok: false},
+		{intervals: Intervals{{0, 2}, {4, 5}}, offset: 4, expected: Interval{4, 5}, ok: true},
+		{intervals: Intervals{{0, 2}, {4, 5}}, offset: 5, expected: Interval{4, 5}, ok: true},
+		{intervals: Intervals{{0, 2}, {4, 5}}, offset: 6, expected: Interval{0, 0}, ok: false},
+	}
+
+	for _, test := range tests {
+		v, ok := test.intervals.Search(test.offset)
+		assert.Equal(t, test.expected, v)
+		assert.Equal(t, test.ok, ok)
+	}
+}
+
+func TestInsertExpected(t *testing.T) {
 	tests := []struct {
 		inserts  Intervals
 		expected Intervals
@@ -43,7 +67,7 @@ func TestExpected(t *testing.T) {
 	}
 }
 
-func TestRandom(t *testing.T) {
+func TestInsertRandom(t *testing.T) {
 	for n := 0; n < 1000; n++ {
 		vs := Intervals{}
 		count := rand.Intn(10) + 1
@@ -86,7 +110,7 @@ func TestRandom(t *testing.T) {
 	}
 }
 
-func TestPanic(t *testing.T) {
+func TestInsertPanic(t *testing.T) {
 	// End before start should panic.
 	assert.Panics(t, func() { Intervals{}.Insert(Interval{2, 1}) })
 }