feature: encoding/mvt: add brotli support

encoding/mvt/README.md

@@ -13,9 +13,11 @@ type Layer struct {
 }
 
 func MarshalGzipped(layers Layers) ([]byte, error)
+func MarshalBrotli(layers Layers) ([]byte, error)
 func Marshal(layers Layers) ([]byte, error)
 
 func UnmarshalGzipped(data []byte) (Layers, error)
+func UnmarshalBrotli(data []byte) (Layers, error)
 func Unmarshal(data []byte) (Layers, error)
 ```
 

encoding/mvt/marshal.go

@@ -7,6 +7,7 @@ import (
 	"sort"
 	"strconv"
 
+	"github.com/andybalholm/brotli"
 	"github.com/paulmach/orb"
 	"github.com/paulmach/orb/encoding/mvt/vectortile"
 	"github.com/paulmach/orb/geojson"
@@ -39,6 +40,28 @@ func MarshalGzipped(layers Layers) ([]byte, error) {
 	return buf.Bytes(), nil
 }
 
+// MarshalBrotli will marshal the layers into Mapbox Vector Tile format
+// and brotli compress the result.
+func MarshalBrotli(layers Layers) ([]byte, error) {
+	data, err := Marshal(layers)
+	if err != nil {
+		return nil, err
+	}
+
+	buf := bytes.NewBuffer(nil)
+	brwriter := brotli.NewWriter(buf)
+
+	if _, err = brwriter.Write(data); err != nil {
+		return nil, err
+	}
+
+	if err := brwriter.Close(); err != nil {
+		return nil, err
+	}
+
+	return buf.Bytes(), nil
+}
+
 // MarshalToVectorTile will take a set of layers and encode them into a Mapbox Vector Tile proto structure.
 // Features that have a nil geometry, for some reason, will be skipped and not included.
 func MarshalToVectorTile(layers Layers) (*vectortile.Tile, error) {

encoding/mvt/marshal_test.go

@@ -69,6 +69,61 @@ func TestMarshalUnmarshalGzipped_Full(t *testing.T) {
 	compareOrbGeometry(t, result.Geometry, expected, xe, ye)
 }
 
+func TestMarshalUnmarshalBrotli_Full(t *testing.T) {
+	tile := maptile.New(8956, 12223, 15)
+	ls := orb.LineString{
+		{-81.60346275, 41.50998572},
+		{-81.6033669, 41.50991259},
+		{-81.60355599, 41.50976036},
+		{-81.6040648, 41.50936811},
+		{-81.60404411, 41.50935405},
+	}
+	expected := ls.Clone()
+
+	f := geojson.NewFeature(ls)
+	f.Properties = geojson.Properties{
+		"source":       "openstreetmap.org",
+		"kind":         "path",
+		"name":         "Uptown Alley",
+		"landuse_kind": "retail",
+		"sort_rank":    float64(354),
+		"kind_detail":  "pedestrian",
+		"min_zoom":     float64(13),
+		"id":           float64(246698394),
+	}
+
+	fc := geojson.NewFeatureCollection()
+	fc.Append(f)
+
+	layers := Layers{NewLayer("roads", fc)}
+
+	// project to the tile coords
+	layers.ProjectToTile(tile)
+
+	// marshal
+	encoded, err := MarshalBrotli(layers)
+	if err != nil {
+		t.Fatalf("marshal error: %v", err)
+	}
+
+	// unmarshal
+	decoded, err := UnmarshalBrotli(encoded)
+	if err != nil {
+		t.Fatalf("unmarshal error: %v", err)
+	}
+
+	// project back
+	decoded.ProjectToWGS84(tile)
+
+	// compare the results
+	result := decoded[0].Features[0]
+	compareProperties(t, result.Properties, f.Properties)
+
+	// compare geometry
+	xe, ye := tileEpsilon(tile)
+	compareOrbGeometry(t, result.Geometry, expected, xe, ye)
+}
+
 func TestMarshalUnmarshalForGeometryCollection(t *testing.T) {
 	tile := maptile.New(8956, 12223, 15)
 	outerRing := orb.Ring{
@@ -109,23 +164,39 @@ func TestMarshalUnmarshalForGeometryCollection(t *testing.T) {
 	// project to the tile coords
 	layers.ProjectToTile(tile)
 
-	// marshal
-	encoded, err := MarshalGzipped(layers)
+	// marshal gzip
+	encodedGzip, err := MarshalGzipped(layers)
 	if err != nil {
-		t.Fatalf("marshal error: %v", err)
+		t.Fatalf("marshal gzip error: %v", err)
 	}
 
-	// unmarshal
-	decoded, err := UnmarshalGzipped(encoded)
+	// unmarshal gzip
+	decodedGzip, err := UnmarshalGzipped(encodedGzip)
 	if err != nil {
-		t.Fatalf("unmarshal error: %v", err)
+		t.Fatalf("unmarshal gzip error: %v", err)
+	}
+
+	// compare the results
+	results := decodedGzip[0].Features
+	compareProperties(t, results[0].Properties, f.Properties)
+
+	// marshal brotli
+	encodedBrotli, err := MarshalBrotli(layers)
+	if err != nil {
+		t.Fatalf("marshal brotli error: %v", err)
+	}
+
+	// unmarshal brotli
+	decodedBrotli, err := UnmarshalBrotli(encodedBrotli)
+	if err != nil {
+		t.Fatalf("unmarshal brotli error: %v", err)
 	}
 
 	// project back
-	decoded.ProjectToWGS84(tile)
+	decodedBrotli.ProjectToWGS84(tile)
 
 	// compare the results
-	results := decoded[0].Features
+	results = decodedBrotli[0].Features
 	compareProperties(t, results[0].Properties, f.Properties)
 
 	// compare geometry

encoding/mvt/unmarshal.go

@@ -5,8 +5,10 @@ import (
 	"compress/gzip"
 	"errors"
 	"fmt"
+	"io"
 	"io/ioutil"
 
+	"github.com/andybalholm/brotli"
 	"github.com/paulmach/orb"
 	"github.com/paulmach/orb/encoding/mvt/vectortile"
 	"github.com/paulmach/orb/geojson"
@@ -31,6 +33,19 @@ func UnmarshalGzipped(data []byte) (Layers, error) {
 	return Unmarshal(decoded)
 }
 
+// UnmarshalBrotli takes brotli compressed Mapbox Vector Tile (MVT) data and uncompresses it
+// before decoding it into a set of layers, It does not project the coordinates.
+func UnmarshalBrotli(data []byte) (Layers, error) {
+	brreader := brotli.NewReader(bytes.NewBuffer(data))
+
+	decoded, err := io.ReadAll(brreader)
+	if err != nil {
+		return nil, fmt.Errorf("failed to unzip: %v", err)
+	}
+
+	return Unmarshal(decoded)
+}
+
 // Unmarshal takes Mapbox Vector Tile (MVT) data and converts into a
 // set of layers, It does not project the coordinates.
 func Unmarshal(data []byte) (Layers, error) {

go.mod

@@ -1,8 +1,9 @@
 module github.com/paulmach/orb
 
-go 1.15
+go 1.22
 
 require (
+	github.com/andybalholm/brotli v1.2.0
 	github.com/gogo/protobuf v1.3.2
 	github.com/paulmach/protoscan v0.2.1
 	go.mongodb.org/mongo-driver v1.11.4

go.sum

@@ -1,3 +1,5 @@
+github.com/andybalholm/brotli v1.2.0 h1:ukwgCxwYrmACq68yiUqwIWnGY0cTPox/M94sVwToPjQ=
+github.com/andybalholm/brotli v1.2.0/go.mod h1:rzTDkvFWvIrjDXZHkuS16NPggd91W3kUSvPlQ1pLaKY=
 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=
@@ -11,10 +13,8 @@ github.com/google/go-cmp v0.5.5/go.mod h1:v8dTdLbMG2kIc/vJvl+f65V22dbkXbowE6jgT/
 github.com/kisielk/errcheck v1.5.0/go.mod h1:pFxgyoBC7bSaBwPgfKdkLd5X25qrDl4LWUI2bnpBCr8=
 github.com/kisielk/gotool v1.0.0/go.mod h1:XhKaO+MFFWcvkIS/tQcRk01m1F5IRFswLeQ+oQHNcck=
 github.com/klauspost/compress v1.13.6/go.mod h1:/3/Vjq9QcHkK5uEr5lBEmyoZ1iFhe47etQ6QUkpK6sk=
-github.com/kr/pretty v0.1.0 h1:L/CwN0zerZDmRFUapSPitk6f+Q3+0za1rQkzVuMiMFI=
 github.com/kr/pretty v0.1.0/go.mod h1:dAy3ld7l9f0ibDNOQOHHMYYIIbhfbHSm3C4ZsoJORNo=
 github.com/kr/pty v1.1.1/go.mod h1:pFQYn66WHrOpPYNljwOMqo10TkYh1fy3cYio2l3bCsQ=
-github.com/kr/text v0.1.0 h1:45sCR5RtlFHMR4UwH9sdQ5TC8v0qDQCHnXt+kaKSTVE=
 github.com/kr/text v0.1.0/go.mod h1:4Jbv+DJW3UT/LiOwJeYQe1efqtUx/iVham/4vfdArNI=
 github.com/montanaflynn/stats v0.0.0-20171201202039-1bf9dbcd8cbe/go.mod h1:wL8QJuTMNUDYhXwkmfOly8iTdp5TEcJFWZD2D7SIkUc=
 github.com/paulmach/protoscan v0.2.1 h1:rM0FpcTjUMvPUNk2BhPJrreDKetq43ChnL+x1sRg8O8=
@@ -30,6 +30,8 @@ github.com/tidwall/pretty v1.0.0/go.mod h1:XNkn88O1ChpSDQmQeStsy+sBenx6DDtFZJxhV
 github.com/xdg-go/pbkdf2 v1.0.0/go.mod h1:jrpuAogTd400dnrH08LKmI/xc1MbPOebTwRqcT5RDeI=
 github.com/xdg-go/scram v1.1.1/go.mod h1:RaEWvsqvNKKvBPvcKeFjrG2cJqOkHTiyTpzz23ni57g=
 github.com/xdg-go/stringprep v1.0.3/go.mod h1:W3f5j4i+9rC0kuIEJL0ky1VpHXQU3ocBgklLGvcBnW8=
+github.com/xyproto/randomstring v1.0.5 h1:YtlWPoRdgMu3NZtP45drfy1GKoojuR7hmRcnhZqKjWU=
+github.com/xyproto/randomstring v1.0.5/go.mod h1:rgmS5DeNXLivK7YprL0pY+lTuhNQW3iGxZ18UQApw/E=
 github.com/youmark/pkcs8 v0.0.0-20181117223130-1be2e3e5546d/go.mod h1:rHwXgn7JulP+udvsHwJoVG1YGAP6VLg4y9I5dyZdqmA=
 github.com/yuin/goldmark v1.1.27/go.mod h1:3hX8gzYuyVAZsxl0MRgGTJEmQBFcNTphYh9decYSb74=
 github.com/yuin/goldmark v1.2.1/go.mod h1:3hX8gzYuyVAZsxl0MRgGTJEmQBFcNTphYh9decYSb74=
@@ -68,13 +70,11 @@ golang.org/x/tools v0.0.0-20210106214847-113979e3529a/go.mod h1:emZCQorbCU4vsT4f
 golang.org/x/xerrors v0.0.0-20190717185122-a985d3407aa7/go.mod h1:I/5z698sn9Ka8TeJc9MKroUUfqBBauWjQqLJ2OPfmY0=
 golang.org/x/xerrors v0.0.0-20191011141410-1b5146add898/go.mod h1:I/5z698sn9Ka8TeJc9MKroUUfqBBauWjQqLJ2OPfmY0=
 golang.org/x/xerrors v0.0.0-20191204190536-9bdfabe68543/go.mod h1:I/5z698sn9Ka8TeJc9MKroUUfqBBauWjQqLJ2OPfmY0=
-golang.org/x/xerrors v0.0.0-20200804184101-5ec99f83aff1 h1:go1bK/D/BFZV2I8cIQd1NKEZ+0owSTG1fDTci4IqFcE=
 golang.org/x/xerrors v0.0.0-20200804184101-5ec99f83aff1/go.mod h1:I/5z698sn9Ka8TeJc9MKroUUfqBBauWjQqLJ2OPfmY0=
 google.golang.org/protobuf v1.26.0-rc.1/go.mod h1:jlhhOSvTdKEhbULTjvd4ARK9grFBp09yW+WbY/TyQbw=
 google.golang.org/protobuf v1.27.1 h1:SnqbnDw1V7RiZcXPx5MEeqPv2s79L9i7BJUlG/+RurQ=
 google.golang.org/protobuf v1.27.1/go.mod h1:9q0QmTI4eRPtz6boOQmLYwt+qCgq0jsYwAQnmE0givc=
 gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
-gopkg.in/check.v1 v1.0.0-20180628173108-788fd7840127 h1:qIbj1fsPNlZgppZ+VLlY7N33q108Sa+fhmuc+sWQYwY=
 gopkg.in/check.v1 v1.0.0-20180628173108-788fd7840127/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
 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=