Flutter OnlinePunctuation (#1854)

flutter/sherpa_onnx/lib/src/online_punctuation.dart

@@ -0,0 +1,99 @@
+import 'dart:ffi';
+import 'package:ffi/ffi.dart';
+
+import './sherpa_onnx_bindings.dart';
+
+class OnlinePunctuationModelConfig {
+  OnlinePunctuationModelConfig(
+      {required this.cnnBiLstm,
+      required this.bpeVocab,
+      this.numThreads = 1,
+      this.provider = 'cpu',
+      this.debug = true});
+
+  @override
+  String toString() {
+    return 'OnlinePunctuationModelConfig(cnnBiLstm: $cnnBiLstm, '
+        'bpeVocab: $bpeVocab, numThreads: $numThreads, '
+        'provider: $provider, debug: $debug)';
+  }
+
+  final String cnnBiLstm;
+  final String bpeVocab;
+  final int numThreads;
+  final String provider;
+  final bool debug;
+}
+
+class OnlinePunctuationConfig {
+  OnlinePunctuationConfig({
+    required this.model,
+  });
+
+  @override
+  String toString() {
+    return 'OnlinePunctuationConfig(model: $model)';
+  }
+
+  final OnlinePunctuationModelConfig model;
+}
+
+class OnlinePunctuation {
+  OnlinePunctuation.fromPtr({required this.ptr, required this.config});
+
+  OnlinePunctuation._({required this.ptr, required this.config});
+
+  // The user has to invoke OnlinePunctuation.free() to avoid memory leak.
+  factory OnlinePunctuation({required OnlinePunctuationConfig config}) {
+    final c = calloc<SherpaOnnxOnlinePunctuationConfig>();
+
+    final cnnBiLstmPtr = config.model.cnnBiLstm.toNativeUtf8();
+    final bpeVocabPtr = config.model.bpeVocab.toNativeUtf8();
+    c.ref.model.cnnBiLstm = cnnBiLstmPtr;
+    c.ref.model.bpeVocab = bpeVocabPtr;
+    c.ref.model.numThreads = config.model.numThreads;
+    c.ref.model.debug = config.model.debug ? 1 : 0;
+
+    final providerPtr = config.model.provider.toNativeUtf8();
+    c.ref.model.provider = providerPtr;
+
+    final ptr = SherpaOnnxBindings.sherpaOnnxCreateOnlinePunctuation?.call(c) ??
+        nullptr;
+
+    // Free the allocated strings and struct memory
+    calloc.free(providerPtr);
+    calloc.free(cnnBiLstmPtr);
+    calloc.free(bpeVocabPtr);
+    calloc.free(c);
+
+    return OnlinePunctuation._(ptr: ptr, config: config);
+  }
+
+  void free() {
+    SherpaOnnxBindings.sherpaOnnxDestroyOnlinePunctuation?.call(ptr);
+    ptr = nullptr;
+  }
+
+  String addPunct(String text) {
+    final textPtr = text.toNativeUtf8();
+
+    final p = SherpaOnnxBindings.sherpaOnnxOnlinePunctuationAddPunct
+            ?.call(ptr, textPtr) ??
+        nullptr;
+
+    calloc.free(textPtr);
+
+    if (p == nullptr) {
+      return '';
+    }
+
+    final ans = p.toDartString();
+
+    SherpaOnnxBindings.sherpaOnnxOnlinePunctuationFreeText?.call(p);
+    
+    return ans;
+  }
+
+  Pointer<SherpaOnnxOnlinePunctuation> ptr;
+  final OnlinePunctuationConfig config;
+}