Export text encoding constants

README.md

@@ -49,8 +49,9 @@ mutable package state.
 
 `Kind` is `text`, `binary`, or `unknown`. `Format` and `MIME` describe the
 physical content. `Encoding` is set for accepted UTF-8, UTF-16LE, or UTF-16BE
-text and never appears as a MIME charset parameter. Compare `Format` against
-the exported `Format*` constants rather than string literals.
+text and never appears as a MIME charset parameter. Compare `Format` and
+`Encoding` against the exported `Format*` and `Encoding*` constants rather
+than string literals.
 
 The format registry contains:
 

example_test.go

@@ -21,3 +21,17 @@ func ExampleDetectPrefix() {
 	// Output:
 	// text need-more
 }
+
+func ExampleResult_Encoding() {
+	result := magic.Detect([]byte("\xff\xfeh\x00i\x00"))
+
+	switch result.Encoding {
+	case magic.EncodingUTF16LE, magic.EncodingUTF16BE:
+		fmt.Println("decode UTF-16 before processing text")
+	case magic.EncodingUTF8:
+		fmt.Println("process text directly")
+	}
+
+	// Output:
+	// decode UTF-16 before processing text
+}

json_test.go

@@ -26,7 +26,7 @@ func TestJSONDetection(t *testing.T) {
 				Kind:     KindText,
 				MIME:     mimeJSON,
 				Format:   FormatJSON,
-				Encoding: encodingUTF8,
+				Encoding: EncodingUTF8,
 			})
 		})
 	}
@@ -70,7 +70,7 @@ func TestInvalidJSONRetainsExistingClassification(t *testing.T) {
 				Kind:     KindText,
 				MIME:     mimeText,
 				Format:   FormatText,
-				Encoding: encodingUTF8,
+				Encoding: EncodingUTF8,
 			})
 		})
 	}
@@ -165,7 +165,7 @@ func TestJSONPrefixDetection(t *testing.T) {
 				Kind:     KindText,
 				MIME:     mimeJSON,
 				Format:   FormatJSON,
-				Encoding: encodingUTF8,
+				Encoding: EncodingUTF8,
 				Reason:   ReasonNeedMore,
 			})
 		})
@@ -199,7 +199,7 @@ func TestInvalidJSONPrefixRetainsExistingClassification(t *testing.T) {
 				Kind:     KindText,
 				MIME:     mimeText,
 				Format:   FormatText,
-				Encoding: encodingUTF8,
+				Encoding: EncodingUTF8,
 				Reason:   ReasonNeedMore,
 			})
 		})

magic.go

@@ -89,10 +89,13 @@ const (
 	mimePE    = "application/vnd.microsoft.portable-executable"
 	mimeWASM  = "application/wasm"
 	mimeAR    = "application/x-archive"
+)
 
-	encodingUTF8    = "utf-8"
-	encodingUTF16LE = "utf-16le"
-	encodingUTF16BE = "utf-16be"
+// Encoding values reported in Result.Encoding.
+const (
+	EncodingUTF8    = "utf-8"
+	EncodingUTF16LE = "utf-16le"
+	EncodingUTF16BE = "utf-16be"
 )
 
 // Detect classifies data as the complete content of a file.

magic_test.go

@@ -25,7 +25,7 @@ func TestDetectPrefix(t *testing.T) {
 				Kind:     KindText,
 				MIME:     mimeText,
 				Format:   FormatText,
-				Encoding: encodingUTF8,
+				Encoding: EncodingUTF8,
 				Reason:   ReasonNeedMore,
 			},
 		},
@@ -125,7 +125,7 @@ func TestDetectDoesNotRetainInput(t *testing.T) {
 		Kind:     KindText,
 		MIME:     mimeText,
 		Format:   FormatText,
-		Encoding: encodingUTF8,
+		Encoding: EncodingUTF8,
 	})
 }
 

signatures_test.go

@@ -221,7 +221,7 @@ func TestTextFormatRegistryAndPrecedence(t *testing.T) {
 		t.Run(test.name, func(t *testing.T) {
 			t.Parallel()
 			got := Detect([]byte(test.input))
-			if got.Kind != KindText || got.Encoding != encodingUTF8 ||
+			if got.Kind != KindText || got.Encoding != EncodingUTF8 ||
 				got.Format != test.format || got.MIME != test.mime {
 				t.Fatalf("Detect() = %#v, want text %s %s", got, test.format, test.mime)
 			}

text.go

@@ -34,7 +34,7 @@ func classifyText(data []byte) Result {
 	if containsDisallowedControlUTF8(data) {
 		return Result{Kind: KindBinary}
 	}
-	return Result{Kind: KindText, Encoding: encodingUTF8}
+	return Result{Kind: KindText, Encoding: EncodingUTF8}
 }
 
 func classifyUTF8BOM(data []byte) Result {
@@ -44,7 +44,7 @@ func classifyUTF8BOM(data []byte) Result {
 	if containsDisallowedControlUTF8(data) {
 		return Result{Kind: KindBinary}
 	}
-	return Result{Kind: KindText, Encoding: encodingUTF8}
+	return Result{Kind: KindText, Encoding: EncodingUTF8}
 }
 
 func classifyUTF16BOM(data []byte, littleEndian bool) Result {
@@ -56,9 +56,9 @@ func classifyUTF16BOM(data []byte, littleEndian bool) Result {
 		return Result{Kind: KindBinary}
 	}
 
-	encoding := encodingUTF16BE
+	encoding := EncodingUTF16BE
 	if littleEndian {
-		encoding = encodingUTF16LE
+		encoding = EncodingUTF16LE
 	}
 	return Result{Kind: KindText, Encoding: encoding}
 }

text_test.go

@@ -26,7 +26,7 @@ func TestTextDecisionTable(t *testing.T) {
 				Kind:     KindText,
 				MIME:     mimeText,
 				Format:   FormatText,
-				Encoding: encodingUTF8,
+				Encoding: EncodingUTF8,
 			},
 		},
 		{
@@ -36,7 +36,7 @@ func TestTextDecisionTable(t *testing.T) {
 				Kind:     KindText,
 				MIME:     mimeText,
 				Format:   FormatText,
-				Encoding: encodingUTF16LE,
+				Encoding: EncodingUTF16LE,
 			},
 		},
 		{
@@ -46,7 +46,7 @@ func TestTextDecisionTable(t *testing.T) {
 				Kind:     KindText,
 				MIME:     mimeText,
 				Format:   FormatText,
-				Encoding: encodingUTF16BE,
+				Encoding: EncodingUTF16BE,
 			},
 		},
 		{
@@ -81,7 +81,7 @@ func TestTextDecisionTable(t *testing.T) {
 				Kind:     KindText,
 				MIME:     mimeText,
 				Format:   FormatText,
-				Encoding: encodingUTF8,
+				Encoding: EncodingUTF8,
 			},
 		},
 		{
@@ -119,7 +119,7 @@ func TestUTF16Validation(t *testing.T) {
 				Kind:     KindText,
 				MIME:     mimeText,
 				Format:   FormatText,
-				Encoding: encodingUTF16LE,
+				Encoding: EncodingUTF16LE,
 			},
 		},
 		{
@@ -129,7 +129,7 @@ func TestUTF16Validation(t *testing.T) {
 				Kind:     KindText,
 				MIME:     mimeText,
 				Format:   FormatText,
-				Encoding: encodingUTF16LE,
+				Encoding: EncodingUTF16LE,
 			},
 		},
 		{
@@ -186,7 +186,7 @@ func TestPlainText(t *testing.T) {
 				Kind:     KindText,
 				MIME:     mimeText,
 				Format:   FormatText,
-				Encoding: encodingUTF8,
+				Encoding: EncodingUTF8,
 			})
 		})
 	}