Read context length and warn if it is very large

Author: amakropoulos

Runtime/LLM.cs

@@ -173,8 +173,13 @@ public void SetModel(string path)
             if (!string.IsNullOrEmpty(model))
             {
                 ModelEntry modelEntry = LLMManager.Get(model);
-                string template = modelEntry != null ? modelEntry.chatTemplate : ChatTemplate.FromGGUF(GetModelLoraPathRuntime(model));
-                SetTemplate(template);
+                if (modelEntry == null) modelEntry = new ModelEntry(GetModelLoraPathRuntime(model));
+                SetTemplate(modelEntry.chatTemplate);
+                Debug.Log(modelEntry.contextLength);
+                if (contextSize == 0 && modelEntry.contextLength > 32768)
+                {
+                    LLMUnitySetup.LogWarning($"The model {path} has very large context size ({modelEntry.contextLength}), consider setting it to a smaller value (<=32768) to avoid filling up the RAM");
+                }
             }
 #if UNITY_EDITOR
             if (!EditorApplication.isPlaying) EditorUtility.SetDirty(this);

Runtime/LLMChatTemplates.cs

@@ -1,5 +1,6 @@
 /// @file
 /// @brief File implementing the chat templates.
+using System;
 using System.Collections.Generic;
 using System.IO;
 using UnityEngine;
@@ -113,9 +114,12 @@ public static string FromTemplate(string template)
         /// <returns>template name</returns>
         public static string FromGGUF(string path)
         {
-            GGUFReader reader = new GGUFReader(path);
-            string name;
+            return FromGGUF(new GGUFReader(path), path);
+        }
 
+        public static string FromGGUF(GGUFReader reader, string path)
+        {
+            string name;
             name = FromTemplate(reader.GetStringField("tokenizer.chat_template"));
             if (name != null) return name;
 

Runtime/LLMGGUF.cs

@@ -125,16 +125,35 @@ public ReaderField GetField(string key)
             return null;
         }
 
+        public byte[] GetGenericField(string key)
+        {
+            ReaderField field = GetField(key);
+            if (field == null || field.parts.Count == 0) return null;
+            return (byte[])field.parts[field.parts.Count - 1];
+        }
+
         /// <summary>
         /// Allows to retrieve a string GGUF field.
         /// </summary>
         /// <param name="key"> GGUF field to retrieve </param>
         /// <returns> Retrieved GGUF value </returns>
         public string GetStringField(string key)
         {
-            ReaderField field = GetField(key);
-            if (field == null || field.parts.Count == 0) return null;
-            return System.Text.Encoding.UTF8.GetString((byte[])field.parts[field.parts.Count - 1]);
+            byte[] value = GetGenericField(key);
+            if (value == null) return null;
+            return System.Text.Encoding.UTF8.GetString(value);
+        }
+
+        /// <summary>
+        /// Allows to retrieve an integer GGUF field.
+        /// </summary>
+        /// <param name="key"> GGUF field to retrieve </param>
+        /// <returns> Retrieved GGUF value </returns>
+        public int GetIntField(string key)
+        {
+            byte[] value = GetGenericField(key);
+            if (value == null) return -1;
+            return BitConverter.ToInt32(value, 0);
         }
 
         private byte[] ReadBytes(int offset, int count)

Runtime/LLMManager.cs

@@ -17,17 +17,25 @@ public class ModelEntry
         public string chatTemplate;
         public string url;
         public bool includeInBuild;
-
+        public int contextLength;
 
         public ModelEntry(string path, bool lora = false, string label = null, string url = null)
         {
             filename = Path.GetFileName(path);
             this.label = label == null ? filename : label;
             this.lora = lora;
             this.path = Path.GetFullPath(path).Replace('\\', '/');
-            chatTemplate = lora ? null : ChatTemplate.FromGGUF(this.path);
             this.url = url;
             includeInBuild = true;
+            chatTemplate = null;
+            contextLength = -1;
+            if (!lora)
+            {
+                GGUFReader reader = new GGUFReader(this.path);
+                chatTemplate = ChatTemplate.FromGGUF(reader, this.path);
+                string arch = reader.GetStringField("general.architecture");
+                if (arch != null) contextLength = reader.GetIntField($"{arch}.context_length");
+            }
         }
 
         public ModelEntry OnlyRequiredFields()