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7 files changed, 1287 insertions, 0 deletions

diff --git a/llama.cpp/examples/llama.android/lib/src/main/java/com/arm/aichat/AiChat.kt b/llama.cpp/examples/llama.android/lib/src/main/java/com/arm/aichat/AiChat.kt
new file mode 100644
index 0000000..b72a24e
--- /dev/null
+++ b/llama.cpp/examples/llama.android/lib/src/main/java/com/arm/aichat/AiChat.kt
@@ -0,0 +1,14 @@
+package com.arm.aichat
+
+import android.content.Context
+import com.arm.aichat.internal.InferenceEngineImpl
+
+/**
+ * Main entry point for Arm's AI Chat library.
+ */
+object AiChat {
+    /**
+     * Get the inference engine single instance.
+     */
+    fun getInferenceEngine(context: Context) = InferenceEngineImpl.getInstance(context)
+}
diff --git a/llama.cpp/examples/llama.android/lib/src/main/java/com/arm/aichat/InferenceEngine.kt b/llama.cpp/examples/llama.android/lib/src/main/java/com/arm/aichat/InferenceEngine.kt
new file mode 100644
index 0000000..26c1668
--- /dev/null
+++ b/llama.cpp/examples/llama.android/lib/src/main/java/com/arm/aichat/InferenceEngine.kt
@@ -0,0 +1,89 @@
+package com.arm.aichat
+
+import com.arm.aichat.InferenceEngine.State
+import kotlinx.coroutines.flow.Flow
+import kotlinx.coroutines.flow.StateFlow
+
+/**
+ * Interface defining the core LLM inference operations.
+ */
+interface InferenceEngine {
+    /**
+     * Current state of the inference engine
+     */
+    val state: StateFlow<State>
+
+    /**
+     * Load a model from the given path.
+     *
+     * @throws UnsupportedArchitectureException if model architecture not supported
+     */
+    suspend fun loadModel(pathToModel: String)
+
+    /**
+     * Sends a system prompt to the loaded model
+     */
+    suspend fun setSystemPrompt(systemPrompt: String)
+
+    /**
+     * Sends a user prompt to the loaded model and returns a Flow of generated tokens.
+     */
+    fun sendUserPrompt(message: String, predictLength: Int = DEFAULT_PREDICT_LENGTH): Flow<String>
+
+    /**
+     * Runs a benchmark with the specified parameters.
+     */
+    suspend fun bench(pp: Int, tg: Int, pl: Int, nr: Int = 1): String
+
+    /**
+     * Unloads the currently loaded model.
+     */
+    fun cleanUp()
+
+    /**
+     * Cleans up resources when the engine is no longer needed.
+     */
+    fun destroy()
+
+    /**
+     * States of the inference engine
+     */
+    sealed class State {
+        object Uninitialized : State()
+        object Initializing : State()
+        object Initialized : State()
+
+        object LoadingModel : State()
+        object UnloadingModel : State()
+        object ModelReady : State()
+
+        object Benchmarking : State()
+        object ProcessingSystemPrompt : State()
+        object ProcessingUserPrompt : State()
+
+        object Generating : State()
+
+        data class Error(val exception: Exception) : State()
+    }
+
+    companion object {
+        const val DEFAULT_PREDICT_LENGTH = 1024
+    }
+}
+
+val State.isUninterruptible
+    get() = this is State.Initializing ||
+        this is State.LoadingModel ||
+        this is State.UnloadingModel ||
+        this is State.Benchmarking ||
+        this is State.ProcessingSystemPrompt ||
+        this is State.ProcessingUserPrompt
+
+val State.isModelLoaded: Boolean
+    get() = this is State.ModelReady ||
+        this is State.Benchmarking ||
+        this is State.ProcessingSystemPrompt ||
+        this is State.ProcessingUserPrompt ||
+        this is State.Generating
+
+class UnsupportedArchitectureException : Exception()
diff --git a/llama.cpp/examples/llama.android/lib/src/main/java/com/arm/aichat/gguf/FileType.kt b/llama.cpp/examples/llama.android/lib/src/main/java/com/arm/aichat/gguf/FileType.kt
new file mode 100644
index 0000000..2f15eef
--- /dev/null
+++ b/llama.cpp/examples/llama.android/lib/src/main/java/com/arm/aichat/gguf/FileType.kt
@@ -0,0 +1,61 @@
+package com.arm.aichat.gguf
+
+import kotlin.collections.get
+
+
+/**
+ * Numerical codes used by `general.file_type` (see llama.cpp repo's `constants.py`).
+ * The `label` matches what llama‑cli prints.
+ */
+enum class FileType(val code: Int, val label: String) {
+    ALL_F32(0, "all F32"),
+    MOSTLY_F16(1, "F16"),
+    MOSTLY_Q4_0(2, "Q4_0"),
+    MOSTLY_Q4_1(3, "Q4_1"),
+    // 4 removed
+    MOSTLY_Q8_0(7, "Q8_0"),
+    MOSTLY_Q5_0(8, "Q5_0"),
+    MOSTLY_Q5_1(9, "Q5_1"),
+
+    /* K‑quants ------------------------------------------------------------ */
+    MOSTLY_Q2_K      (10, "Q2_K - Medium"),
+    MOSTLY_Q3_K_S    (11, "Q3_K - Small"),
+    MOSTLY_Q3_K_M    (12, "Q3_K - Medium"),
+    MOSTLY_Q3_K_L    (13, "Q3_K - Large"),
+    MOSTLY_Q4_K_S    (14, "Q4_K - Small"),
+    MOSTLY_Q4_K_M    (15, "Q4_K - Medium"),
+    MOSTLY_Q5_K_S    (16, "Q5_K - Small"),
+    MOSTLY_Q5_K_M    (17, "Q5_K - Medium"),
+    MOSTLY_Q6_K      (18, "Q6_K"),
+
+    /* IQ quants ----------------------------------------------------------- */
+    MOSTLY_IQ2_XXS   (19, "IQ2_XXS - 2.06 bpw"),
+    MOSTLY_IQ2_XS    (20, "IQ2_XS - 2.31 bpw"),
+    MOSTLY_Q2_K_S    (21, "Q2_K - Small"),
+    MOSTLY_IQ3_XS    (22, "IQ3_XS - 3.30 bpw"),
+    MOSTLY_IQ3_XXS   (23, "IQ3_XXS - 3.06 bpw"),
+    MOSTLY_IQ1_S     (24, "IQ1_S - 1.56 bpw"),
+    MOSTLY_IQ4_NL    (25, "IQ4_NL - 4.5 bpw"),
+    MOSTLY_IQ3_S     (26, "IQ3_S - 3.44 bpw"),
+    MOSTLY_IQ3_M     (27, "IQ3_M - 3.66 bpw"),
+    MOSTLY_IQ2_S     (28, "IQ2_S - 2.50 bpw"),
+    MOSTLY_IQ2_M     (29, "IQ2_M - 2.70 bpw"),
+    MOSTLY_IQ4_XS    (30, "IQ4_XS - 4.25 bpw"),
+    MOSTLY_IQ1_M     (31, "IQ1_M - 1.75 bpw"),
+
+    /* BF16 & Ternary ------------------------------------------------------ */
+    MOSTLY_BF16      (32, "BF16"),
+    MOSTLY_TQ1_0     (36, "TQ1_0 - 1.69 bpw ternary"),
+    MOSTLY_TQ2_0     (37, "TQ2_0 - 2.06 bpw ternary"),
+
+    /* Special flag -------------------------------------------------------- */
+    GUESSED(1024, "(guessed)"),
+
+    UNKNOWN(-1, "unknown");
+
+    companion object {
+        private val map = entries.associateBy(FileType::code)
+
+        fun fromCode(code: Int?): FileType = map[code] ?: UNKNOWN
+    }
+}
diff --git a/llama.cpp/examples/llama.android/lib/src/main/java/com/arm/aichat/gguf/GgufMetadata.kt b/llama.cpp/examples/llama.android/lib/src/main/java/com/arm/aichat/gguf/GgufMetadata.kt
new file mode 100644
index 0000000..5e1971a
--- /dev/null
+++ b/llama.cpp/examples/llama.android/lib/src/main/java/com/arm/aichat/gguf/GgufMetadata.kt
@@ -0,0 +1,132 @@
+package com.arm.aichat.gguf
+
+import java.io.IOException
+
+
+/**
+ * Structured metadata of GGUF
+ */
+data class GgufMetadata(
+    // Basic file info
+    val version: GgufVersion,
+    val tensorCount: Long,
+    val kvCount: Long,
+
+    // General info
+    val basic: BasicInfo,
+    val author: AuthorInfo? = null,
+    val additional: AdditionalInfo? = null,
+    val architecture: ArchitectureInfo? = null,
+    val baseModels: List<BaseModelInfo>? = null,
+    val tokenizer: TokenizerInfo? = null,
+
+    // Derivative info
+    val dimensions: DimensionsInfo? = null,
+    val attention: AttentionInfo? = null,
+    val rope: RopeInfo? = null,
+    val experts: ExpertsInfo? = null
+) {
+    enum class GgufVersion(val code: Int, val label: String) {
+        /** First public draft; little‑endian only, no alignment key. */
+        LEGACY_V1(1, "Legacy v1"),
+
+        /** Added split‑file support and some extra metadata keys. */
+        EXTENDED_V2(2, "Extended v2"),
+
+        /** Current spec: endian‑aware, mandatory alignment, fully validated. */
+        VALIDATED_V3(3, "Validated v3");
+
+        companion object {
+            fun fromCode(code: Int): GgufVersion =
+                entries.firstOrNull { it.code == code }
+                    ?: throw IOException("Unknown GGUF version code $code")
+        }
+
+        override fun toString(): String = "$label (code=$code)"
+    }
+
+    data class BasicInfo(
+        val uuid: String? = null,
+        val name: String? = null,
+        val nameLabel: String? = null,
+        val sizeLabel: String? = null,  // Size label like "7B"
+    )
+
+    data class AuthorInfo(
+        val organization: String? = null,
+        val author: String? = null,
+        val doi: String? = null,
+        val url: String? = null,
+        val repoUrl: String? = null,
+        val license: String? = null,
+        val licenseLink: String? = null,
+    )
+
+    data class AdditionalInfo(
+        val type: String? = null,
+        val description: String? = null,
+        val tags: List<String>? = null,
+        val languages: List<String>? = null,
+    )
+
+    data class ArchitectureInfo(
+        val architecture: String? = null,
+        val fileType: Int? = null,
+        val vocabSize: Int? = null,
+        val finetune: String? = null,
+        val quantizationVersion: Int? = null,
+    )
+
+    data class BaseModelInfo(
+        val name: String? = null,
+        val author: String? = null,
+        val version: String? = null,
+        val organization: String? = null,
+        val url: String? = null,
+        val doi: String? = null,
+        val uuid: String? = null,
+        val repoUrl: String? = null,
+    )
+
+    data class TokenizerInfo(
+        val model: String? = null,
+        val bosTokenId: Int? = null,
+        val eosTokenId: Int? = null,
+        val unknownTokenId: Int? = null,
+        val paddingTokenId: Int? = null,
+        val addBosToken: Boolean? = null,
+        val addEosToken: Boolean? = null,
+        val chatTemplate: String? = null,
+    )
+
+    data class DimensionsInfo(
+        val contextLength: Int? = null,
+        val embeddingSize: Int? = null,
+        val blockCount: Int? = null,
+        val feedForwardSize: Int? = null,
+    )
+
+    data class AttentionInfo(
+        val headCount: Int? = null,
+        val headCountKv: Int? = null,
+        val keyLength: Int? = null,
+        val valueLength: Int? = null,
+        val layerNormEpsilon: Float? = null,
+        val layerNormRmsEpsilon: Float? = null,
+    )
+
+    data class RopeInfo(
+        val frequencyBase: Float? = null,
+        val dimensionCount: Int? = null,
+        val scalingType: String? = null,
+        val scalingFactor: Float? = null,
+        val attnFactor: Float? = null,
+        val originalContextLength: Int? = null,
+        val finetuned: Boolean? = null,
+    )
+
+    data class ExpertsInfo(
+        val count: Int? = null,
+        val usedCount: Int? = null,
+    )
+}
diff --git a/llama.cpp/examples/llama.android/lib/src/main/java/com/arm/aichat/gguf/GgufMetadataReader.kt b/llama.cpp/examples/llama.android/lib/src/main/java/com/arm/aichat/gguf/GgufMetadataReader.kt
new file mode 100644
index 0000000..264a6c0
--- /dev/null
+++ b/llama.cpp/examples/llama.android/lib/src/main/java/com/arm/aichat/gguf/GgufMetadataReader.kt
@@ -0,0 +1,77 @@
+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
+
+/**
+ * Interface for reading GGUF metadata from model files.
+ * Use `GgufMetadataReader.create()` to get an instance.
+ */
+interface GgufMetadataReader {
+    /**
+     * Reads the magic number from the specified file path.
+     *
+     * @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
+     */
+    suspend fun ensureSourceFileFormat(context: Context, uri: Uri): Boolean
+
+    /**
+     * Reads and parses GGUF metadata from the specified file path.
+     *
+     * @param input the [InputStream] obtained from a readable file or content
+     * @return Structured metadata extracted from the file
+     * @throws IOException if file is damaged or cannot be read
+     * @throws InvalidFileFormatException if file format is invalid
+     */
+    suspend fun readStructuredMetadata(input: InputStream): GgufMetadata
+
+    companion object {
+        private val DEFAULT_SKIP_KEYS = setOf(
+            "tokenizer.chat_template",
+            "tokenizer.ggml.scores",
+            "tokenizer.ggml.tokens",
+            "tokenizer.ggml.token_type"
+        )
+
+        /**
+         * Creates a default GgufMetadataReader instance
+         */
+        fun create(): GgufMetadataReader = GgufMetadataReaderImpl(
+            skipKeys = DEFAULT_SKIP_KEYS,
+            arraySummariseThreshold = 1_000
+        )
+
+        /**
+         * Creates a GgufMetadataReader with custom configuration
+         *
+         * @param skipKeys Keys whose value should be skipped entirely (not kept in the result map)
+         * @param arraySummariseThreshold If ≥0, arrays longer get summarised, not materialised;
+         *                                If -1, never summarise.
+         */
+        fun create(
+            skipKeys: Set<String> = DEFAULT_SKIP_KEYS,
+            arraySummariseThreshold: Int = 1_000
+        ): GgufMetadataReader = GgufMetadataReaderImpl(
+            skipKeys = skipKeys,
+            arraySummariseThreshold = arraySummariseThreshold
+        )
+    }
+}
+
+class InvalidFileFormatException : IOException()
diff --git a/llama.cpp/examples/llama.android/lib/src/main/java/com/arm/aichat/internal/InferenceEngineImpl.kt b/llama.cpp/examples/llama.android/lib/src/main/java/com/arm/aichat/internal/InferenceEngineImpl.kt
new file mode 100644
index 0000000..a293796
--- /dev/null
+++ b/llama.cpp/examples/llama.android/lib/src/main/java/com/arm/aichat/internal/InferenceEngineImpl.kt
@@ -0,0 +1,324 @@
+package com.arm.aichat.internal
+
+import android.content.Context
+import android.util.Log
+import com.arm.aichat.InferenceEngine
+import com.arm.aichat.UnsupportedArchitectureException
+import com.arm.aichat.internal.InferenceEngineImpl.Companion.getInstance
+import dalvik.annotation.optimization.FastNative
+import kotlinx.coroutines.CancellationException
+import kotlinx.coroutines.CoroutineScope
+import kotlinx.coroutines.Dispatchers
+import kotlinx.coroutines.ExperimentalCoroutinesApi
+import kotlinx.coroutines.SupervisorJob
+import kotlinx.coroutines.cancel
+import kotlinx.coroutines.flow.Flow
+import kotlinx.coroutines.flow.MutableStateFlow
+import kotlinx.coroutines.flow.StateFlow
+import kotlinx.coroutines.flow.asStateFlow
+import kotlinx.coroutines.flow.flow
+import kotlinx.coroutines.flow.flowOn
+import kotlinx.coroutines.launch
+import kotlinx.coroutines.runBlocking
+import kotlinx.coroutines.withContext
+import java.io.File
+import java.io.IOException
+
+/**
+ * JNI wrapper for the llama.cpp library providing Android-friendly access to large language models.
+ *
+ * This class implements a singleton pattern for managing the lifecycle of a single LLM instance.
+ * All operations are executed on a dedicated single-threaded dispatcher to ensure thread safety
+ * with the underlying C++ native code.
+ *
+ * The typical usage flow is:
+ * 1. Get instance via [getInstance]
+ * 2. Load a model with [loadModel]
+ * 3. Send prompts with [sendUserPrompt]
+ * 4. Generate responses as token streams
+ * 5. Perform [cleanUp] when done with a model
+ * 6. Properly [destroy] when completely done
+ *
+ * State transitions are managed automatically and validated at each operation.
+ *
+ * @see ai_chat.cpp for the native implementation details
+ */
+internal class InferenceEngineImpl private constructor(
+    private val nativeLibDir: String
+) : InferenceEngine {
+
+    companion object {
+        private val TAG = InferenceEngineImpl::class.java.simpleName
+
+        @Volatile
+        private var instance: InferenceEngine? = null
+
+        /**
+         * Create or obtain [InferenceEngineImpl]'s single instance.
+         *
+         * @param Context for obtaining native library directory
+         * @throws IllegalArgumentException if native library path is invalid
+         * @throws UnsatisfiedLinkError if library failed to load
+         */
+        internal fun getInstance(context: Context) =
+            instance ?: synchronized(this) {
+                val nativeLibDir = context.applicationInfo.nativeLibraryDir
+                require(nativeLibDir.isNotBlank()) { "Expected a valid native library path!" }
+
+                try {
+                    Log.i(TAG, "Instantiating InferenceEngineImpl,,,")
+                    InferenceEngineImpl(nativeLibDir).also { instance = it }
+                } catch (e: UnsatisfiedLinkError) {
+                    Log.e(TAG, "Failed to load native library from $nativeLibDir", e)
+                    throw e
+                }
+            }
+    }
+
+    /**
+     * JNI methods
+     * @see ai_chat.cpp
+     */
+    @FastNative
+    private external fun init(nativeLibDir: String)
+
+    @FastNative
+    private external fun load(modelPath: String): Int
+
+    @FastNative
+    private external fun prepare(): Int
+
+    @FastNative
+    private external fun systemInfo(): String
+
+    @FastNative
+    private external fun benchModel(pp: Int, tg: Int, pl: Int, nr: Int): String
+
+    @FastNative
+    private external fun processSystemPrompt(systemPrompt: String): Int
+
+    @FastNative
+    private external fun processUserPrompt(userPrompt: String, predictLength: Int): Int
+
+    @FastNative
+    private external fun generateNextToken(): String?
+
+    @FastNative
+    private external fun unload()
+
+    @FastNative
+    private external fun shutdown()
+
+    private val _state =
+        MutableStateFlow<InferenceEngine.State>(InferenceEngine.State.Uninitialized)
+    override val state: StateFlow<InferenceEngine.State> = _state.asStateFlow()
+
+    private var _readyForSystemPrompt = false
+    @Volatile
+    private var _cancelGeneration = false
+
+    /**
+     * Single-threaded coroutine dispatcher & scope for LLama asynchronous operations
+     */
+    @OptIn(ExperimentalCoroutinesApi::class)
+    private val llamaDispatcher = Dispatchers.IO.limitedParallelism(1)
+    private val llamaScope = CoroutineScope(llamaDispatcher + SupervisorJob())
+
+    init {
+        llamaScope.launch {
+            try {
+                check(_state.value is InferenceEngine.State.Uninitialized) {
+                    "Cannot load native library in ${_state.value.javaClass.simpleName}!"
+                }
+                _state.value = InferenceEngine.State.Initializing
+                Log.i(TAG, "Loading native library...")
+                System.loadLibrary("ai-chat")
+                init(nativeLibDir)
+                _state.value = InferenceEngine.State.Initialized
+                Log.i(TAG, "Native library loaded! System info: \n${systemInfo()}")
+
+            } catch (e: Exception) {
+                Log.e(TAG, "Failed to load native library", e)
+                throw e
+            }
+        }
+    }
+
+    /**
+     * Load the LLM
+     */
+    override suspend fun loadModel(pathToModel: String) =
+        withContext(llamaDispatcher) {
+            check(_state.value is InferenceEngine.State.Initialized) {
+                "Cannot load model in ${_state.value.javaClass.simpleName}!"
+            }
+
+            try {
+                Log.i(TAG, "Checking access to model file... \n$pathToModel")
+                File(pathToModel).let {
+                    require(it.exists()) { "File not found" }
+                    require(it.isFile) { "Not a valid file" }
+                    require(it.canRead()) { "Cannot read file" }
+                }
+
+                Log.i(TAG, "Loading model... \n$pathToModel")
+                _readyForSystemPrompt = false
+                _state.value = InferenceEngine.State.LoadingModel
+                load(pathToModel).let {
+                    // TODO-han.yin: find a better way to pass other error codes
+                    if (it != 0) throw UnsupportedArchitectureException()
+                }
+                prepare().let {
+                    if (it != 0) throw IOException("Failed to prepare resources")
+                }
+                Log.i(TAG, "Model loaded!")
+                _readyForSystemPrompt = true
+
+                _cancelGeneration = false
+                _state.value = InferenceEngine.State.ModelReady
+            } catch (e: Exception) {
+                Log.e(TAG, (e.message ?: "Error loading model") + "\n" + pathToModel, e)
+                _state.value = InferenceEngine.State.Error(e)
+                throw e
+            }
+        }
+
+    /**
+     * Process the plain text system prompt
+     *
+     * TODO-han.yin: return error code if system prompt not correct processed?
+     */
+    override suspend fun setSystemPrompt(prompt: String) =
+        withContext(llamaDispatcher) {
+            require(prompt.isNotBlank()) { "Cannot process empty system prompt!" }
+            check(_readyForSystemPrompt) { "System prompt must be set ** RIGHT AFTER ** model loaded!" }
+            check(_state.value is InferenceEngine.State.ModelReady) {
+                "Cannot process system prompt in ${_state.value.javaClass.simpleName}!"
+            }
+
+            Log.i(TAG, "Sending system prompt...")
+            _readyForSystemPrompt = false
+            _state.value = InferenceEngine.State.ProcessingSystemPrompt
+            processSystemPrompt(prompt).let { result ->
+                if (result != 0) {
+                    RuntimeException("Failed to process system prompt: $result").also {
+                        _state.value = InferenceEngine.State.Error(it)
+                        throw it
+                    }
+                }
+            }
+            Log.i(TAG, "System prompt processed! Awaiting user prompt...")
+            _state.value = InferenceEngine.State.ModelReady
+        }
+
+    /**
+     * Send plain text user prompt to LLM, which starts generating tokens in a [Flow]
+     */
+    override fun sendUserPrompt(
+        message: String,
+        predictLength: Int,
+    ): Flow<String> = flow {
+        require(message.isNotEmpty()) { "User prompt discarded due to being empty!" }
+        check(_state.value is InferenceEngine.State.ModelReady) {
+            "User prompt discarded due to: ${_state.value.javaClass.simpleName}"
+        }
+
+        try {
+            Log.i(TAG, "Sending user prompt...")
+            _readyForSystemPrompt = false
+            _state.value = InferenceEngine.State.ProcessingUserPrompt
+
+            processUserPrompt(message, predictLength).let { result ->
+                if (result != 0) {
+                    Log.e(TAG, "Failed to process user prompt: $result")
+                    return@flow
+                }
+            }
+
+            Log.i(TAG, "User prompt processed. Generating assistant prompt...")
+            _state.value = InferenceEngine.State.Generating
+            while (!_cancelGeneration) {
+                generateNextToken()?.let { utf8token ->
+                    if (utf8token.isNotEmpty()) emit(utf8token)
+                } ?: break
+            }
+            if (_cancelGeneration) {
+                Log.i(TAG, "Assistant generation aborted per requested.")
+            } else {
+                Log.i(TAG, "Assistant generation complete. Awaiting user prompt...")
+            }
+            _state.value = InferenceEngine.State.ModelReady
+        } catch (e: CancellationException) {
+            Log.i(TAG, "Assistant generation's flow collection cancelled.")
+            _state.value = InferenceEngine.State.ModelReady
+            throw e
+        } catch (e: Exception) {
+            Log.e(TAG, "Error during generation!", e)
+            _state.value = InferenceEngine.State.Error(e)
+            throw e
+        }
+    }.flowOn(llamaDispatcher)
+
+    /**
+     * Benchmark the model
+     */
+    override suspend fun bench(pp: Int, tg: Int, pl: Int, nr: Int): String =
+        withContext(llamaDispatcher) {
+            check(_state.value is InferenceEngine.State.ModelReady) {
+                "Benchmark request discarded due to: $state"
+            }
+            Log.i(TAG, "Start benchmark (pp: $pp, tg: $tg, pl: $pl, nr: $nr)")
+            _readyForSystemPrompt = false   // Just to be safe
+            _state.value = InferenceEngine.State.Benchmarking
+            benchModel(pp, tg, pl, nr).also {
+                _state.value = InferenceEngine.State.ModelReady
+            }
+        }
+
+    /**
+     * Unloads the model and frees resources, or reset error states
+     */
+    override fun cleanUp() {
+        _cancelGeneration = true
+        runBlocking(llamaDispatcher) {
+            when (val state = _state.value) {
+                is InferenceEngine.State.ModelReady -> {
+                    Log.i(TAG, "Unloading model and free resources...")
+                    _readyForSystemPrompt = false
+                    _state.value = InferenceEngine.State.UnloadingModel
+
+                    unload()
+
+                    _state.value = InferenceEngine.State.Initialized
+                    Log.i(TAG, "Model unloaded!")
+                    Unit
+                }
+
+                is InferenceEngine.State.Error -> {
+                    Log.i(TAG, "Resetting error states...")
+                    _state.value = InferenceEngine.State.Initialized
+                    Log.i(TAG, "States reset!")
+                    Unit
+                }
+
+                else -> throw IllegalStateException("Cannot unload model in ${state.javaClass.simpleName}")
+            }
+        }
+    }
+
+    /**
+     * Cancel all ongoing coroutines and free GGML backends
+     */
+    override fun destroy() {
+        _cancelGeneration = true
+        runBlocking(llamaDispatcher) {
+            _readyForSystemPrompt = false
+            when(_state.value) {
+                is InferenceEngine.State.Uninitialized -> {}
+                is InferenceEngine.State.Initialized -> shutdown()
+                else -> { unload(); shutdown() }
+            }
+        }
+        llamaScope.cancel()
+    }
+}
diff --git a/llama.cpp/examples/llama.android/lib/src/main/java/com/arm/aichat/internal/gguf/GgufMetadataReaderImpl.kt b/llama.cpp/examples/llama.android/lib/src/main/java/com/arm/aichat/internal/gguf/GgufMetadataReaderImpl.kt
new file mode 100644
index 0000000..bf250ac
--- /dev/null
+++ b/llama.cpp/examples/llama.android/lib/src/main/java/com/arm/aichat/internal/gguf/GgufMetadataReaderImpl.kt
@@ -0,0 +1,590 @@
+package com.arm.aichat.internal.gguf
+
+import android.content.Context
+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
+
+
+/**
+ * Utility class to read GGUF model files and extract metadata key-value pairs.
+ * This parser reads the header and metadata of a GGUF v3 file (little-endian) and skips tensor data.
+ */
+internal class GgufMetadataReaderImpl(
+    private val skipKeys: Set<String>,
+    private val arraySummariseThreshold: Int,
+) : GgufMetadataReader {
+    companion object {
+        private const val ARCH_LLAMA = "llama"
+    }
+
+    /** Enum corresponding to GGUF metadata value types (for convenience and array element typing). */
+    enum class MetadataType(val code: Int) {
+        UINT8(0), INT8(1), UINT16(2), INT16(3),
+        UINT32(4), INT32(5), FLOAT32(6), BOOL(7),
+        STRING(8), ARRAY(9), UINT64(10), INT64(11), FLOAT64(12);
+        companion object {
+            private val codeMap = entries.associateBy(MetadataType::code)
+            fun fromCode(code: Int): MetadataType = codeMap[code]
+                ?: throw IOException("Unknown metadata value type code: $code")
+        }
+    }
+
+    /** Sealed class hierarchy for metadata values, providing type-safe representations for each GGUF metadata type. */
+    sealed class MetadataValue {
+        data class UInt8(val value: UByte) : MetadataValue()       // 0:  8-bit unsigned int
+        data class Int8(val value: Byte) : MetadataValue()         // 1:  8-bit signed int
+        data class UInt16(val value: UShort) : MetadataValue()     // 2:  16-bit unsigned int (little-endian)
+        data class Int16(val value: Short) : MetadataValue()       // 3:  16-bit signed int (little-endian)
+        data class UInt32(val value: UInt) : MetadataValue()       // 4:  32-bit unsigned int (little-endian)
+        data class Int32(val value: Int) : MetadataValue()         // 5:  32-bit signed int (little-endian)
+        data class Float32(val value: Float) : MetadataValue()     // 6:  32-bit IEEE754 float
+        data class Bool(val value: Boolean) : MetadataValue()      // 7:  Boolean (1-byte, 0=false, 1=true)
+        data class StringVal(val value: String) : MetadataValue()  // 8:  UTF-8 string (length-prefixed)
+        data class ArrayVal(val elementType: MetadataType, val elements: List<MetadataValue>) : MetadataValue()
+        data class UInt64(val value: ULong) : MetadataValue()      // 10: 64-bit unsigned int (little-endian)
+        data class Int64(val value: Long) : MetadataValue()        // 11: 64-bit signed int (little-endian)
+        data class Float64(val value: Double) : MetadataValue()    // 12: 64-bit IEEE754 double
+    }
+
+    /* Convert MetadataValue to plain Kotlin primitives for allMetadata map */
+    private fun MetadataValue.toPrimitive(): Any = when (this) {
+        is MetadataValue.UInt8     -> value
+        is MetadataValue.Int8      -> value
+        is MetadataValue.UInt16    -> value
+        is MetadataValue.Int16     -> value
+        is MetadataValue.UInt32    -> value
+        is MetadataValue.Int32     -> value
+        is MetadataValue.Float32   -> value
+        is MetadataValue.Bool      -> value
+        is MetadataValue.StringVal -> value
+        is MetadataValue.UInt64    -> value
+        is MetadataValue.Int64     -> value
+        is MetadataValue.Float64   -> value
+        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.
+     *
+     * @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(context: Context, uri: Uri): Boolean =
+        context.contentResolver.openInputStream(uri)?.buffered()?.use { ensureMagic(it) } == true
+
+    /** Reads the 4‑byte magic; throws if magic ≠ "GGUF". */
+    private fun ensureMagic(input: InputStream): Boolean =
+        ByteArray(4).let {
+            if (input.read(it) != 4) throw IOException("Not a valid file!")
+            it.contentEquals(byteArrayOf(0x47, 0x47, 0x55, 0x46)) // "GGUF"
+        }
+
+    /**
+     * High‑level entry point: parses a `.gguf` file on disk and returns the fully
+     * populated [GgufMetadata] tree.
+     *
+     * Steps performed internally:
+     * 1.  Reads and validates the 8‑byte header (`"GGUF"` magic + version).
+     * 2.  Streams through the key‑value section, skipping large blobs if the key
+     *     appears in [skipKeys] or if an array exceeds [arraySummariseThreshold].
+     * 3.  Converts the resulting raw map into strongly‑typed sub‑structures
+     *     (basic info, tokenizer, rope, etc.).
+     *
+     * The method is STREAMING‑ONLY: tensors are never mapped or loaded into
+     * memory, so even multi‑GB model files can be processed in < 50 ms.
+     *
+     * @param path Absolute or relative filesystem path to a `.gguf` file.
+     * @return A [GgufMetadata] instance containing all recognised metadata plus
+     *         an `allMetadata` map with any keys that were not given a dedicated
+     *         field.
+     * @throws IOException if the file is not GGUF, the version is unsupported,
+     *         or the metadata block is truncated / corrupt.
+     */
+    override suspend fun readStructuredMetadata(input: InputStream): GgufMetadata {
+        // ── 1. header ──────────────────────────────────────────────────────────
+        // throws on mismatch
+        val version       = ensureMagicAndVersion(input)
+        val tensorCount   = readLittleLong(input)
+        val kvCount       = readLittleLong(input)
+
+        // ── 2. metadata map (reuse our raw parser, but we need access to the stream) ──
+        val meta = readMetaMap(input, kvCount)    // <String, MetadataValue>
+
+        // ── 3. build structured object ────────────────────────────────────────
+        return buildStructured(meta, version, tensorCount, kvCount)
+    }
+
+    /** Reads the 4‑byte magic + 4‑byte version; throws if magic ≠ "GGUF". */
+    private fun ensureMagicAndVersion(input: InputStream): GgufMetadata.GgufVersion {
+        if (!ensureMagic(input)) throw InvalidFileFormatException()
+        return GgufMetadata.GgufVersion.fromCode(readLEUInt32(input))
+    }
+
+    /**
+     * Read an unsigned 32‑bit little‑endian integer.
+     *
+     * @throws IOException if fewer than four bytes are available.
+     */
+    private fun readLEUInt32(input: InputStream): Int {
+        val b0 = input.read(); val b1 = input.read(); val b2 = input.read(); val b3 = input.read()
+        if (b3 == -1) throw IOException("Unexpected EOF while reading UInt32")
+        return (b3 and 0xFF shl 24) or
+            (b2 and 0xFF shl 16) or
+            (b1 and 0xFF shl  8) or
+            (b0 and 0xFF)
+    }
+
+    /**
+     * Low‑level helper that reads the entire “key-value” section from the current
+     * stream position.
+     *
+     * @param input  Open stream positioned JUST AFTER the header.
+     * @param kvCnt  Number of key‑value pairs (taken from the header).
+     * @return       Mutable map with one [MetadataValue] for every key that is NOT skipped.
+     *
+     * The function honours [skipKeys] and [arraySummariseThreshold] by invoking
+     * [skipValue] or [parseValue] accordingly.
+     */
+    private fun readMetaMap(input: InputStream, kvCnt: Long): Map<String, MetadataValue> =
+        mutableMapOf<String, MetadataValue>().apply {
+             repeat(kvCnt.toInt()) {
+                 val key = readString(input)
+                 val valueT = MetadataType.fromCode(littleEndianBytesToInt(input.readNBytesExact(4)))
+                 if (key in skipKeys) {
+                     skipValue(input, valueT)
+                 } else {
+                     this[key] = parseValue(input, valueT)
+                 }
+             }
+         }
+
+    /**
+     * Converts a flat [Map]<[String], [MetadataValue]> into the strongly‑typed
+     * [GgufMetadata] tree used by the rest of the app.
+     *
+     * Only the keys listed in the spec are copied into dedicated data classes;
+     * everything else is preserved in `GgufMetadata.allMetadata`.
+     *
+     * @param m            Raw key/value map.
+     * @param version      GGUF file‑format version (enum).
+     * @param tensorCnt    Number of tensors (from the header).
+     * @param kvCnt        Total metadata pair count (from the header).
+     */
+    private fun buildStructured(
+        m: Map<String, MetadataValue>,
+        version: GgufMetadata.GgufVersion,
+        tensorCnt: Long,
+        kvCnt: Long
+    ): GgufMetadata {
+        // ---------- helpers ----------
+        fun String.str()  = (m[this] as? MetadataValue.StringVal)?.value
+        fun String.bool() = (m[this] as? MetadataValue.Bool)?.value
+        fun String.i32()  = (m[this] as? MetadataValue.Int32)?.value
+        fun String.u32()  = (m[this] as? MetadataValue.UInt32)?.value?.toInt()
+        fun String.f32()  = (m[this] as? MetadataValue.Float32)?.value
+        fun String.f64()  = (m[this] as? MetadataValue.Float64)?.value?.toFloat()
+        fun String.strList(): List<String>? =
+            (m[this] as? MetadataValue.ArrayVal)
+                ?.elements
+                ?.mapNotNull { (it as? MetadataValue.StringVal)?.value }
+
+        val arch = "general.architecture".str() ?: ARCH_LLAMA
+
+        // -------------- populate sections ----------------
+        val basic = GgufMetadata.BasicInfo(
+            uuid      = "general.uuid".str(),
+            name      = "general.basename".str(),
+            nameLabel = "general.name".str(),
+            sizeLabel = "general.size_label".str()
+        )
+
+        val author = GgufMetadata.AuthorInfo(
+            organization = "general.organization".str(),
+            author       = "general.author".str(),
+            doi          = "general.doi".str(),
+            url          = "general.url".str(),
+            repoUrl      = "general.repo_url".str(),
+            license      = "general.license".str(),
+            licenseLink  = "general.license.link".str()
+        ).takeUnless {
+            organization == null && author == null && doi == null &&
+                url == null && repoUrl == null && license == null && licenseLink == null
+        }
+
+        val additional = GgufMetadata.AdditionalInfo(
+            type        = "general.type".str(),
+            description = "general.description".str(),
+            tags        = "general.tags".strList(),
+            languages   = "general.languages".strList()
+        ).takeUnless {
+            type == null && description == null && tags == null && languages == null
+        }
+
+        val architectureInfo = GgufMetadata.ArchitectureInfo(
+            architecture        = arch,
+            fileType            = "general.file_type".u32(),
+            vocabSize           = "$arch.vocab_size".u32(),
+            finetune            = "general.finetune".str(),
+            quantizationVersion = "general.quantization_version".u32()
+        ).takeUnless { fileType == null && vocabSize == null && finetune == null && quantizationVersion == null }
+
+        val baseModels = buildList {
+            val n = "general.base_model.count".u32() ?: 0
+            for (i in 0 until n) {
+                fun k(s: String) = "general.base_model.$i.$s"
+                add(
+                    GgufMetadata.BaseModelInfo(
+                        name         = k("name").str(),
+                        author       = k("author").str(),
+                        version      = k("version").str(),
+                        organization = k("organization").str(),
+                        url          = k("url").str(),
+                        doi          = k("doi").str(),
+                        uuid         = k("uuid").str(),
+                        repoUrl      = k("repo_url").str(),
+                    )
+                )
+            }
+        }.takeIf { it.isNotEmpty() }
+
+        val tokenizer = GgufMetadata.TokenizerInfo(
+            model            = "tokenizer.ggml.model".str(),
+            bosTokenId       = "tokenizer.ggml.bos_token_id".u32(),
+            eosTokenId       = "tokenizer.ggml.eos_token_id".u32(),
+            unknownTokenId   = "tokenizer.ggml.unknown_token_id".u32(),
+            paddingTokenId   = "tokenizer.ggml.padding_token_id".u32(),
+            addBosToken      = "tokenizer.ggml.add_bos_token".bool(),
+            addEosToken      = "tokenizer.ggml.add_eos_token".bool(),
+            chatTemplate     = "tokenizer.chat_template".str()
+        ).takeUnless { model == null && bosTokenId == null && eosTokenId == null &&
+            unknownTokenId == null && paddingTokenId == null &&
+            addBosToken == null && addEosToken == null && chatTemplate == null
+        }
+
+        val dimensions = GgufMetadata.DimensionsInfo(
+            contextLength    = "$arch.context_length".u32(),
+            embeddingSize    = "$arch.embedding_length".u32(),
+            blockCount       = "$arch.block_count".u32(),
+            feedForwardSize  = "$arch.feed_forward_length".u32()
+        ).takeUnless { contextLength == null && embeddingSize == null && blockCount == null && feedForwardSize == null }
+
+        val attention = GgufMetadata.AttentionInfo(
+            headCount             = "$arch.attention.head_count".u32(),
+            headCountKv           = "$arch.attention.head_count_kv".u32(),
+            keyLength             = "$arch.attention.key_length".u32(),
+            valueLength           = "$arch.attention.value_length".u32(),
+            layerNormEpsilon      = "$arch.attention.layer_norm_epsilon".f32(),
+            layerNormRmsEpsilon   = "$arch.attention.layer_norm_rms_epsilon".f32(),
+        ).takeUnless { headCount == null && headCountKv == null && keyLength == null && valueLength == null &&
+            layerNormEpsilon == null && layerNormRmsEpsilon == null
+        }
+
+        val rope = GgufMetadata.RopeInfo(
+            frequencyBase          = "$arch.rope.freq_base".f32(),
+            dimensionCount         = "$arch.rope.dimension_count".u32(),
+            scalingType            = "$arch.rope.scaling.type".str(),
+            scalingFactor          = "$arch.rope.scaling.factor".f32(),
+            attnFactor             = "$arch.rope.scaling.attn_factor".f32(),
+            originalContextLength  = "$arch.rope.scaling.original_context_length".u32(),
+            finetuned              = "$arch.rope.scaling.finetuned".bool()
+        ).takeUnless { frequencyBase == null && dimensionCount == null &&
+            scalingType == null && scalingFactor == null && attnFactor == null &&
+            originalContextLength == null && finetuned == null
+        }
+
+        val experts = GgufMetadata.ExpertsInfo(
+            count      = "$arch.expert_count".u32(),
+            usedCount  = "$arch.expert_used_count".u32()
+        ).takeUnless { count == null && usedCount == null }
+
+        return GgufMetadata(
+            version = version,
+            tensorCount = tensorCnt,
+            kvCount = kvCnt,
+            basic = basic,
+            author = author,
+            additional = additional,
+            architecture = architectureInfo,
+            baseModels = baseModels,
+            tokenizer = tokenizer,
+            dimensions = dimensions,
+            attention = attention,
+            rope = rope,
+            experts = experts
+        )
+    }
+
+    /**
+     * Recursively parses a metadata value of the given type from the input stream.
+     * @param input The input stream positioned at the start of the value.
+     * @param type The metadata value type to parse.
+     */
+    private fun parseValue(input: InputStream, type: MetadataType): MetadataValue = when (type) {
+        MetadataType.UINT8 -> {
+            // 1-byte unsigned integer
+            val byteVal = input.read()
+            if (byteVal == -1) throw IOException("Unexpected EOF while reading uint8 value.")
+            MetadataValue.UInt8(byteVal.toUByte())
+        }
+        MetadataType.INT8 -> {
+            // 1-byte signed integer
+            val byteVal = input.read()
+            if (byteVal == -1) throw IOException("Unexpected EOF while reading int8 value.")
+            MetadataValue.Int8(byteVal.toByte())
+        }
+        MetadataType.UINT16 -> {
+            // 2-byte unsigned integer (little-endian)
+            val bytes = ByteArray(2)
+            if (input.read(bytes) != 2) throw IOException("Unexpected EOF while reading uint16 value.")
+            // Combine two bytes (little-endian) into an unsigned 16-bit value
+            val u16 = ((bytes[1].toInt() and 0xFF) shl 8) or (bytes[0].toInt() and 0xFF)
+            MetadataValue.UInt16(u16.toUShort())
+        }
+        MetadataType.INT16 -> {
+            // 2-byte signed integer (little-endian)
+            val bytes = ByteArray(2)
+            if (input.read(bytes) != 2) throw IOException("Unexpected EOF while reading int16 value.")
+            // Combine to 16-bit and interpret as signed
+            val i16 = ((bytes[1].toInt() and 0xFF) shl 8) or (bytes[0].toInt() and 0xFF)
+            MetadataValue.Int16(i16.toShort())
+        }
+        MetadataType.UINT32 -> {
+            // 4-byte unsigned integer (little-endian)
+            val bytes = ByteArray(4)
+            if (input.read(bytes) != 4) throw IOException("Unexpected EOF while reading uint32 value.")
+            // Combine four bytes into a 32-bit value (as Long to avoid overflow), then convert to UInt
+            val u32 = (bytes[3].toLong() and 0xFFL shl 24) or
+                (bytes[2].toLong() and 0xFFL shl 16) or
+                (bytes[1].toLong() and 0xFFL shl 8) or
+                (bytes[0].toLong() and 0xFFL)
+            MetadataValue.UInt32(u32.toUInt())
+        }
+        MetadataType.INT32 -> {
+            // 4-byte signed integer (little-endian)
+            val bytes = ByteArray(4)
+            if (input.read(bytes) != 4) throw IOException("Unexpected EOF while reading int32 value.")
+            // Combine four bytes into a 32-bit signed int
+            val i32 = (bytes[3].toInt() and 0xFF shl 24) or
+                (bytes[2].toInt() and 0xFF shl 16) or
+                (bytes[1].toInt() and 0xFF shl 8) or
+                (bytes[0].toInt() and 0xFF)
+            MetadataValue.Int32(i32)
+        }
+        MetadataType.FLOAT32 -> {
+            // 4-byte IEEE 754 float (little-endian)
+            val bytes = ByteArray(4)
+            if (input.read(bytes) != 4) throw IOException("Unexpected EOF while reading float32 value.")
+            // Assemble 4 bytes into a 32-bit int bit-pattern, then convert to Float
+            val bits = (bytes[3].toInt() and 0xFF shl 24) or
+                (bytes[2].toInt() and 0xFF shl 16) or
+                (bytes[1].toInt() and 0xFF shl 8) or
+                (bytes[0].toInt() and 0xFF)
+            val floatVal = Float.fromBits(bits)
+            MetadataValue.Float32(floatVal)
+        }
+        MetadataType.BOOL -> {
+            // 1-byte boolean (0 = false, 1 = true)
+            val byteVal = input.read()
+            if (byteVal == -1) throw IOException("Unexpected EOF while reading boolean value.")
+            if (byteVal != 0 && byteVal != 1) {
+                throw IOException("Invalid boolean value: $byteVal (must be 0 or 1).")
+            }
+            MetadataValue.Bool(byteVal != 0)
+        }
+        MetadataType.STRING -> {
+            // UTF-8 string (length-prefixed with 8-byte length)
+            val str = readString(input)
+            MetadataValue.StringVal(str)
+        }
+        MetadataType.ARRAY -> {
+            val elemType = MetadataType.fromCode(littleEndianBytesToInt(input.readNBytesExact(4)))
+            val len      = readLittleLong(input)
+            val count    = len.toInt()
+
+            if (arraySummariseThreshold >= 0 && count > arraySummariseThreshold) {
+                // fast‑forward without allocation
+                repeat(count) { skipValue(input, elemType) }
+                MetadataValue.StringVal("Array($elemType, $count items) /* summarised */")
+            } else {
+                val list = ArrayList<MetadataValue>(count)
+                repeat(count) { list += parseValue(input, elemType) }
+                MetadataValue.ArrayVal(elemType, list)
+            }
+        }
+        MetadataType.UINT64 -> {
+            // 8-byte unsigned integer (little-endian)
+            val bytes = ByteArray(8)
+            if (input.read(bytes) != 8) throw IOException("Unexpected EOF while reading uint64 value.")
+            // Combine 8 bytes into an unsigned 64-bit (ULong). Use ULong for full 0 to 2^64-1 range.
+            val u64 = (bytes[7].toULong() and 0xFFuL shl 56) or
+                (bytes[6].toULong() and 0xFFuL shl 48) or
+                (bytes[5].toULong() and 0xFFuL shl 40) or
+                (bytes[4].toULong() and 0xFFuL shl 32) or
+                (bytes[3].toULong() and 0xFFuL shl 24) or
+                (bytes[2].toULong() and 0xFFuL shl 16) or
+                (bytes[1].toULong() and 0xFFuL shl 8) or
+                (bytes[0].toULong() and 0xFFuL)
+            MetadataValue.UInt64(u64)
+        }
+        MetadataType.INT64 -> {
+            // 8-byte signed integer (little-endian)
+            val bytes = ByteArray(8)
+            if (input.read(bytes) != 8) throw IOException("Unexpected EOF while reading int64 value.")
+            // Combine 8 bytes into a signed 64-bit value (Long)
+            val i64 = (bytes[7].toLong() and 0xFFL shl 56) or
+                (bytes[6].toLong() and 0xFFL shl 48) or
+                (bytes[5].toLong() and 0xFFL shl 40) or
+                (bytes[4].toLong() and 0xFFL shl 32) or
+                (bytes[3].toLong() and 0xFFL shl 24) or
+                (bytes[2].toLong() and 0xFFL shl 16) or
+                (bytes[1].toLong() and 0xFFL shl 8) or
+                (bytes[0].toLong() and 0xFFL)
+            MetadataValue.Int64(i64)
+        }
+        MetadataType.FLOAT64 -> {
+            // 8-byte IEEE 754 double (little-endian)
+            val bytes = ByteArray(8)
+            if (input.read(bytes) != 8) throw IOException("Unexpected EOF while reading float64 value.")
+            // Assemble 8 bytes into a 64-bit bit-pattern, then convert to Double
+            val bits = (bytes[7].toLong() and 0xFFL shl 56) or
+                (bytes[6].toLong() and 0xFFL shl 48) or
+                (bytes[5].toLong() and 0xFFL shl 40) or
+                (bytes[4].toLong() and 0xFFL shl 32) or
+                (bytes[3].toLong() and 0xFFL shl 24) or
+                (bytes[2].toLong() and 0xFFL shl 16) or
+                (bytes[1].toLong() and 0xFFL shl 8) or
+                (bytes[0].toLong() and 0xFFL)
+            val doubleVal = Double.fromBits(bits)
+            MetadataValue.Float64(doubleVal)
+        }
+    }
+
+
+    private fun <T> T?.takeUnless(check: T.() -> Boolean): T? =
+        this?.takeIf { !it.check() }
+
+    /** Helper: Skip a value in the stream without storing it (still maintains pointer). */
+    private fun skipValue(input: InputStream, type: MetadataType) {
+        when (type) {
+            MetadataType.UINT8, MetadataType.INT8, MetadataType.BOOL -> input.skipFully(1)
+            MetadataType.UINT16, MetadataType.INT16                  -> input.skipFully(2)
+            MetadataType.UINT32, MetadataType.INT32, MetadataType.FLOAT32 -> input.skipFully(4)
+            MetadataType.UINT64, MetadataType.INT64, MetadataType.FLOAT64 -> input.skipFully(8)
+            MetadataType.STRING -> {
+                val len = readLittleLong(input); input.skipFully(len)
+            }
+            MetadataType.ARRAY -> {
+                val elemType = MetadataType.fromCode(littleEndianBytesToInt(input.readNBytesExact(4)))
+                val len      = readLittleLong(input)
+                repeat(len.toInt()) { skipValue(input, elemType) }   // recursive skip
+            }
+        }
+    }
+
+    /** Helper: Read an 8-byte little-endian unsigned value and return it as a signed Long (assuming it fits in 63 bits). */
+    private fun readLittleLong(input: InputStream): Long {
+        val bytes = ByteArray(8)
+        input.readFully(bytes)
+
+        // Combine 8 bytes into a 64-bit value (Little Endian).
+        // Note: If the value exceeds Long.MAX_VALUE (bit 63 is 1), this will produce a negative Long (two's complement).
+        // In our context (lengths/counts), such extremely large values are not expected.
+        return (bytes[7].toLong() and 0xFFL shl 56) or
+            (bytes[6].toLong() and 0xFFL shl 48) or
+            (bytes[5].toLong() and 0xFFL shl 40) or
+            (bytes[4].toLong() and 0xFFL shl 32) or
+            (bytes[3].toLong() and 0xFFL shl 24) or
+            (bytes[2].toLong() and 0xFFL shl 16) or
+            (bytes[1].toLong() and 0xFFL shl 8) or
+            (bytes[0].toLong() and 0xFFL)
+    }
+
+    /** Helper: Read a GGUF string from the stream (8-byte length followed by UTF-8 bytes). */
+    private fun readString(input: InputStream): String =
+        // Read 8-byte little-endian length (number of bytes in the string).
+        readLittleLong(input).let { len ->
+            if (len < 0 || len > Int.MAX_VALUE) throw IOException("String too long: $len")
+
+            // Read the UTF-8 bytes of the given length.
+            ByteArray(len.toInt()).let {
+                if (it.isNotEmpty()) input.readFully(it)
+                String(it, Charsets.UTF_8)
+            }
+        }
+
+    /** Helper: Convert a 4-byte little-endian byte array to a 32-bit integer. */
+    private fun littleEndianBytesToInt(bytes: ByteArray): Int =
+        // Note: assumes bytes length is 4.
+        (bytes[3].toInt() and 0xFF shl 24) or
+            (bytes[2].toInt() and 0xFF shl 16) or
+            (bytes[1].toInt() and 0xFF shl 8) or
+            (bytes[0].toInt() and 0xFF)
+
+    /**
+     * Robust skip that works the same on JDK 11 and Android’s desugared runtime.
+     *
+     * @param n  Number of bytes to advance in the stream.
+     * @throws IOException on premature EOF.
+     */
+    private fun InputStream.skipFully(n: Long) {
+        var remaining = n
+        val scratch = ByteArray(8192)                 // read‑and‑toss buffer
+        while (remaining > 0) {
+            val skipped = skip(remaining)
+            when {
+                skipped > 0      -> remaining -= skipped               // normal fast path
+                skipped == 0L    -> {
+                    // fallback: read and discard
+                    val read = read(scratch, 0, minOf(remaining, scratch.size.toLong()).toInt())
+                    if (read == -1) throw IOException("EOF while skipping $n bytes")
+                    remaining -= read
+                }
+                else             -> throw IOException("Skip returned negative value")
+            }
+        }
+    }
+
+    /**
+     * Extension that keeps reading until the requested number of bytes are filled.
+     * Falls back to `read()` when `skip()` returns 0, which happens on some Android
+     * streams.
+     *
+     * @param buf  Destination buffer.
+     * @param len  Number of bytes to fill (defaults to `buf.size`).
+     * @throws IOException on premature EOF.
+     */
+    private fun InputStream.readFully(buf: ByteArray, len: Int = buf.size) {
+        var off = 0
+        while (off < len) {
+            val n = read(buf, off, len - off)
+            if (n == -1) throw IOException("EOF after $off of $len bytes")
+            off += n
+        }
+    }
+
+    /**
+     * Read EXACTLY `n` bytes or throw – never returns a partially‑filled array.
+     * This is used for small fixed‑length reads (e.g. 4‑byte type codes).
+     *
+     * @throws IOException on premature EOF.
+     */
+    private fun InputStream.readNBytesExact(n: Int) = ByteArray(n).also {
+        if (read(it) != n) throw IOException("Unexpected EOF")
+    }
+}