add GetImageSize and GetImageSizeFromString

README.md

@@ -153,6 +153,13 @@ This package implements some PHP functions by Golang. Please note that it's impo
 | [file_get_contents](https://www.php.net/manual/en/function.file-get-contents.php) | [FileGetContents](https://godoc.org/github.com/hyperjiang/php#FileGetContents) |
 | [file_put_contents](https://www.php.net/manual/en/function.file-put-contents.php) | [FilePutContents](https://godoc.org/github.com/hyperjiang/php#FilePutContents) |
 
+### Image Functions
+
+| PHP function                                         | Golang function                                            |
+| ---------------------------------------------------- | ---------------------------------------------------------- |
+| [getimagesize](https://www.php.net/manual/en/function.getimagesize.php) | [GetImageSize](https://godoc.org/github.com/hyperjiang/php#GetImageSize) |
+| [getimagesizefromstring](https://www.php.net/manual/en/function.getimagesizefromstring.php) | [GetImageSizeFromString](https://godoc.org/github.com/hyperjiang/php#GetImageSizeFromString) |
+
 ### Network Functions
 
 | PHP function                                         | Golang function                                            |

image.go

@@ -0,0 +1,60 @@
+package php
+
+import (
+	"bytes"
+	"image"
+	_ "image/gif"  // gif format
+	_ "image/jpeg" // jpeg format
+	_ "image/png"  // png format
+	"mime"
+	"os"
+)
+
+// ImageInfo stores the info of an image
+type ImageInfo struct {
+	Width  int
+	Height int
+	Format string
+	Mime   string
+}
+
+// GetImageSize gets the size of an image
+func GetImageSize(filename string) (ImageInfo, error) {
+
+	var info ImageInfo
+
+	file, err := os.Open(filename)
+	defer file.Close()
+	if err != nil {
+		return info, err
+	}
+
+	cfg, format, err := image.DecodeConfig(file)
+	if err != nil {
+		return info, err
+	}
+
+	info.Width = cfg.Width
+	info.Height = cfg.Height
+	info.Format = format
+	info.Mime = mime.TypeByExtension("." + format)
+
+	return info, nil
+}
+
+// GetImageSizeFromString gets the size of an image from a string
+func GetImageSizeFromString(data []byte) (ImageInfo, error) {
+	var info ImageInfo
+
+	cfg, format, err := image.DecodeConfig(bytes.NewReader(data))
+	if err != nil {
+		return info, err
+	}
+
+	info.Width = cfg.Width
+	info.Height = cfg.Height
+	info.Format = format
+	info.Mime = mime.TypeByExtension("." + format)
+
+	return info, nil
+}

image_test.go

@@ -0,0 +1,104 @@
+package php
+
+import (
+	_ "image/gif"
+	_ "image/jpeg"
+	_ "image/png"
+	"io/ioutil"
+	"reflect"
+	"testing"
+)
+
+func TestGetimagesize(t *testing.T) {
+	type args struct {
+		filename string
+	}
+	tests := []struct {
+		name    string
+		args    args
+		want    ImageInfo
+		wantErr bool
+	}{
+		{
+			"happy flow",
+			args{"./fish.jpg"},
+			ImageInfo{
+				Width:  559,
+				Height: 533,
+				Format: "jpeg",
+				Mime:   "image/jpeg",
+			},
+			false,
+		},
+		{
+			"no such file",
+			args{"./not-exist-file"},
+			ImageInfo{},
+			true,
+		},
+		{
+			"unknown format",
+			args{"./LICENSE"},
+			ImageInfo{},
+			true,
+		},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			got, err := GetImageSize(tt.args.filename)
+			if (err != nil) != tt.wantErr {
+				t.Errorf("GetImageSize() error = %v, wantErr %v", err, tt.wantErr)
+				return
+			}
+			if !reflect.DeepEqual(got, tt.want) {
+				t.Errorf("GetImageSize() = %v, want %v", got, tt.want)
+			}
+		})
+	}
+}
+
+func TestGetImageSizeFromString(t *testing.T) {
+
+	data1, _ := ioutil.ReadFile("./fish.jpg")
+	data2, _ := ioutil.ReadFile("./LICENSE")
+
+	type args struct {
+		data []byte
+	}
+	tests := []struct {
+		name    string
+		args    args
+		want    ImageInfo
+		wantErr bool
+	}{
+		{
+			"happy flow",
+			args{data1},
+			ImageInfo{
+				Width:  559,
+				Height: 533,
+				Format: "jpeg",
+				Mime:   "image/jpeg",
+			},
+			false,
+		},
+		{
+			"unknown format",
+			args{data2},
+			ImageInfo{},
+			true,
+		},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			got, err := GetImageSizeFromString(tt.args.data)
+			if (err != nil) != tt.wantErr {
+				t.Errorf("GetImageSizeFromString() error = %v, wantErr %v", err, tt.wantErr)
+				return
+			}
+			if !reflect.DeepEqual(got, tt.want) {
+				t.Errorf("GetImageSizeFromString() = %v, want %v", got, tt.want)
+			}
+		})
+	}
+}