lib: add File version for GGUF Magic number verification

examples/llama.android/lib/src/main/java/com/arm/aichat/gguf/GgufMetadataReader.kt

@@ -3,6 +3,7 @@ package com.arm.aichat.gguf
 import android.content.Context
 import android.net.Uri
 import com.arm.aichat.internal.gguf.GgufMetadataReaderImpl
+import java.io.File
 import java.io.IOException
 import java.io.InputStream
 
@@ -14,8 +15,17 @@ interface GgufMetadataReader {
     /**
      * Reads the magic number from the specified file path.
      *
-     * @param context Context for obtaining ContentResolver
-     * @param uri Uri to the GGUF file provided by ContentProvider
+     * @param file Java File to the GGUF file with absolute path
+     * @return true if file is valid GGUF, otherwise false
+     * @throws InvalidFileFormatException if file format is invalid
+     */
+    suspend fun ensureSourceFileFormat(file: File): Boolean
+
+    /**
+     * Reads the magic number from the specified file path.
+     *
+     * @param context Context for obtaining [android.content.ContentProvider]
+     * @param uri Uri to the GGUF file provided by [android.content.ContentProvider]
      * @return true if file is valid GGUF, otherwise false
      * @throws InvalidFileFormatException if file format is invalid
      */

examples/llama.android/lib/src/main/java/com/arm/aichat/internal/gguf/GgufMetadataReaderImpl.kt

@@ -5,6 +5,7 @@ import android.net.Uri
 import com.arm.aichat.gguf.GgufMetadata
 import com.arm.aichat.gguf.GgufMetadataReader
 import com.arm.aichat.gguf.InvalidFileFormatException
+import java.io.File
 import java.io.IOException
 import java.io.InputStream
 
@@ -67,6 +68,16 @@ internal class GgufMetadataReaderImpl(
         is MetadataValue.ArrayVal  -> elements.map { it.toPrimitive() }
     }
 
+    /**
+     * Reads the magic number from the specified file path.
+     *
+     * @param context Context for obtaining ContentResolver
+     * @param uri Uri to the GGUF file provided by ContentProvider
+     * @return true if file is valid GGUF, otherwise false
+     */
+    override suspend fun ensureSourceFileFormat(file: File): Boolean =
+        file.inputStream().buffered().use { ensureMagic(it) }
+
     /**
      * Reads the magic number from the specified file path.
      *