Add benchmark for some common files

Author: gabriel-vasile

CONTRIBUTING.md

@@ -7,3 +7,6 @@ Code contributions must respect these rules:
  - code must be test covered
  - code must be formatted using gofmt tool
  - exported names must be documented
+
+**Important**: By submitting a pull request, you agree to allow the project
+owner to license your work under the same license as that used by the project.

README.md

@@ -67,8 +67,8 @@ containing the string "foobar" at the start of their first line:
     ```go
 	mime, extension := mimetype.Detect([]byte("foobar\nfoo foo bar"))
     ```
-See [TestAppend](https://github.com/gabriel-vasile/mimetype/blob/master/mime_test.go) for a working example.
-See [Contribute](https://github.com/gabriel-vasile/mimetype#contributing) if you consider the missing mime type should be included in the library by default.
+See [TestAppend](mime_test.go) for a working example.
+See [Contributing](CONTRIBUTING.md) if you consider the missing mime type should be included in the library by default.
 
 ## Supported mimes
 ##### Application
@@ -95,5 +95,5 @@ containing specific metadata files.
   <img alt="structure" src="mimetype.gif" width="88%">
 </div>
 
-## Contribute
-See [CONTRIBUTING.md](CONTRIBUTING.md)
+## Contributing
+See [CONTRIBUTING.md](CONTRIBUTING.md).

mime.go

@@ -1,5 +1,5 @@
-// Package mimetype uses magic number signatures to detect the mime type and
-// extension of a file.
+// Package mimetype uses magic number signatures
+// to detect the mime type and extension of a file.
 package mimetype
 
 import (
@@ -18,8 +18,8 @@ func Detect(in []byte) (mime, extension string) {
 	return n.Mime(), n.Extension()
 }
 
-// DetectReader returns the mime type and extension of the byte slice read
-// from the provided reader.
+// DetectReader returns the mime type and extension
+// of the byte slice read from the provided reader.
 func DetectReader(r io.Reader) (mime, extension string, err error) {
 	in := make([]byte, matchers.ReadLimit)
 	n, err := r.Read(in)

mime_test.go

@@ -7,6 +7,8 @@ import (
 	"os"
 	"path/filepath"
 	"testing"
+
+	"github.com/gabriel-vasile/mimetype/matchers"
 )
 
 const testDataDir = "testdata"
@@ -28,6 +30,7 @@ var files = map[string]*Node{
 
 	// images
 	"a.png":  Png,
+	"a.jpg":  Jpg,
 	"a.psd":  Psd,
 	"a.webp": Webp,
 	"a.tif":  Tiff,
@@ -166,3 +169,24 @@ func TestAppend(t *testing.T) {
 func TestTreePrint(t *testing.T) {
 	t.Logf("\n%s", Root.Tree())
 }
+
+func BenchmarkMatchDetect(b *testing.B) {
+	files := []string{"a.png", "a.jpg", "a.pdf", "a.zip", "a.docx", "a.doc"}
+	data, fLen := [][matchers.ReadLimit]byte{}, len(files)
+	for _, f := range files {
+		d := [matchers.ReadLimit]byte{}
+
+		file, err := os.Open(filepath.Join(testDataDir, f))
+		if err != nil {
+			b.Fatal(err)
+		}
+
+		io.ReadFull(file, d[:])
+		data = append(data, d)
+	}
+
+	b.ResetTimer()
+	for n := 0; n < b.N; n++ {
+		Detect(data[n%fLen][:])
+	}
+}

node.go

@@ -4,8 +4,8 @@ import "fmt"
 
 type (
 	// Node represents a node in the matchers tree structure.
-	// It holds the mime type, the extension and the function to check whether
-	// a byte slice has the mime type
+	// It holds the mime type, the extension and the function
+	// to check whether a byte slice has the mime type
 	Node struct {
 		mime      string
 		extension string

testdata/a.jpg

@@ -3,8 +3,8 @@ package mimetype
 import "github.com/gabriel-vasile/mimetype/matchers"
 
 // Root is a matcher which passes for any slice of bytes.
-// When a matcher passes the check, the children matchers are tried in order to
-// find a more accurate mime type.
+// When a matcher passes the check, the children matchers
+// are tried in order to find a more accurate mime type.
 var Root = NewNode("application/octet-stream", "", matchers.True,
 	SevenZ, Zip, Pdf, Doc, Xls, Ppt, Ps, Psd, Ogg,
 	Png, Jpg, Gif, Webp, Tiff, Bmp, Ico,