examples : iOS example with swift ui (#4159)

* copy to llama.cpp as subdir

* attempt enabling metal, fails

* ggml metal compiles!

* Update README.md

* initial conversion to new format, utf8 errors?

* bug fixes, but now has an invalid memory access :(

* added O3, now has insufficient memory access

* begin sync with master

* update to match latest code, new errors

* fixed it!

* fix for loop conditionals, increase result size

* fix current workflow errors

* attempt a llama.swiftui workflow

* Update .github/workflows/build.yml

Co-authored-by: Georgi Gerganov <ggerganov@gmail.com>

---------

Co-authored-by: Georgi Gerganov <ggerganov@gmail.com>

examples/llama.swiftui/llama.swiftui/Models/LlamaState.swift

@@ -0,0 +1,45 @@
+import Foundation
+
+@MainActor
+class LlamaState: ObservableObject {
+    @Published var messageLog = ""
+
+    private var llamaContext: LlamaContext?
+    private var modelUrl: URL? {
+        Bundle.main.url(forResource: "q8_0", withExtension: "gguf", subdirectory: "models")
+        // Bundle.main.url(forResource: "llama-2-7b-chat", withExtension: "Q2_K.gguf", subdirectory: "models")
+    }
+    init() {
+        do {
+            try loadModel()
+        } catch {
+            messageLog += "Error!\n"
+        }
+    }
+
+    private func loadModel() throws {
+        messageLog += "Loading model...\n"
+        if let modelUrl {
+            llamaContext = try LlamaContext.createContext(path: modelUrl.path())
+            messageLog += "Loaded model \(modelUrl.lastPathComponent)\n"
+        } else {
+            messageLog += "Could not locate model\n"
+        }
+    }
+
+    func complete(text: String) async {
+        guard let llamaContext else {
+            return
+        }
+        messageLog += "Attempting to complete text...\n"
+        await llamaContext.completion_init(text: text)
+        messageLog += "\(text)"
+
+        while await llamaContext.n_cur <= llamaContext.n_len {
+            let result = await llamaContext.completion_loop()
+            messageLog += "\(result)"
+        }
+        await llamaContext.clear()
+        messageLog += "\n\ndone\n"
+    }
+}