Fix lint config and pointer switch

Exclude our public API and external tests from revive's package-directory rule.

Collapse the pointer offset switch to avoid identical branch warnings.

Remove duplicate package comments to satisfy godoclint.

Author: oschwald

.golangci.yml

@@ -128,6 +128,11 @@ linters:
           disabled: true
         - name: nested-structs
           disabled: true
+        - name: package-directory-mismatch
+          severity: warning
+          arguments:
+            - ignore-directories:
+                - maxminddb-golang
         - name: unchecked-type-assertion
           disabled: true
         - name: unhandled-error

internal/decoder/data_decoder.go

@@ -1,4 +1,3 @@
-// Package decoder decodes values in the data section.
 package decoder
 
 import (
@@ -238,14 +237,12 @@ func (d *DataDecoder) decodePointer(
 
 	var pointerValueOffset uint
 	switch pointerSize {
-	case 1:
+	case 1, 4:
 		pointerValueOffset = 0
 	case 2:
 		pointerValueOffset = 2048
 	case 3:
 		pointerValueOffset = 526336
-	case 4:
-		pointerValueOffset = 0
 	default:
 		return 0, 0, mmdberrors.NewInvalidDatabaseError("invalid pointer size: %d", pointerSize)
 	}

internal/decoder/decoder.go

@@ -1,3 +1,4 @@
+// Package decoder provides low-level decoding utilities for MaxMind DB data.
 package decoder
 
 import (

internal/decoder/reflection.go

@@ -1,4 +1,3 @@
-// Package decoder decodes values in the data section.
 package decoder
 
 import (

internal/decoder/string_cache.go

@@ -1,4 +1,3 @@
-// Package decoder decodes values in the data section.
 package decoder
 
 import (

mmdbdata/type.go

@@ -1,4 +1,3 @@
-// Package mmdbdata provides types and interfaces for working with MaxMind DB data.
 package mmdbdata
 
 import "github.com/oschwald/maxminddb-golang/v2/internal/decoder"