Initial commit: FunASR Speech Recognition Toolkit

Add complete FunASR codebase including models, runtime, and documentation.
2026-07-09 22:38:58 +08:00
commit 6116b1f3c6
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+// Copyright 2020  Jiayu DU
+
+// See ../../COPYING for clarification regarding multiple authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//  http://www.apache.org/licenses/LICENSE-2.0
+//
+// THIS CODE IS PROVIDED *AS IS* BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+// KIND, EITHER EXPRESS OR IMPLIED, INCLUDING WITHOUT LIMITATION ANY IMPLIED
+// WARRANTIES OR CONDITIONS OF TITLE, FITNESS FOR A PARTICULAR PURPOSE,
+// MERCHANTABLITY OR NON-INFRINGEMENT.
+// See the Apache 2 License for the specific language governing permissions and
+// limitations under the License.
+#ifdef HAVE_KENLM
+#include "lm/kenlm.h"
+
+namespace kaldi {
+
+void KenLm::ComputeSymbolToWordIndexMapping(std::string symbol_table_filename) {
+  // count symbol table size
+  int num_syms = 0;
+  std::string line;
+  std::ifstream is(symbol_table_filename);
+  while(std::getline(is, line)) {
+    if (!line.empty()) num_syms++;
+  }
+
+  symid_to_wid_.clear();
+  symid_to_wid_.resize(num_syms, 0);
+
+  is.clear();
+  is.seekg(0);
+  int num_mapped = 0;
+  while (std::getline(is, line)) {
+    std::vector<std::string> fields;
+    SplitStringToVector(line, " ", true, &fields);
+    if (fields.size() == 2) {
+      std::string sym = fields[0];
+      int32 symid = 0;  ConvertStringToInteger(fields[1], &symid);
+      // mark special LM word
+      if (sym == bos_sym_) {
+        bos_symid_ = symid;
+      } else if (sym == eos_sym_) {
+        eos_symid_ = symid;
+      } else if (sym == "<unk>" || sym == "<UNK>") {
+        unk_sym_ = sym;
+        unk_symid_ = symid;
+      }
+      // check vocabulary consistency between kaldi and kenlm.
+      // note we always handle <unk> & <UNK> as a pair, 
+      // so don't worry about the literal mismatch
+      // between Kaldi and kenlm arpa (<UNK> vs <unk>)
+      WordIndex wid = vocab_->Index(sym.c_str());
+      if ((wid == vocab_->Index("<unk>") || wid == vocab_->Index("<UNK>")) 
+          && sym != "<unk>" && sym != "<UNK>"
+          && sym != "<eps>"
+          && sym != "#0") {
+        KALDI_ERR << "found mismatched symbol: " << sym
+                  << ", this symbol is in Kaldi, but is unseen in KenLm"
+                  << ", they should have strictly consistent vocabulary.";
+      } else {
+        symid_to_wid_[symid] = wid;
+        num_mapped += 1;
+      }
+    }
+  }
+  KALDI_ASSERT(num_mapped == symid_to_wid_.size());
+  KALDI_LOG << "Successfully mapped " << num_mapped 
+            << " Kaldi symbols to KenLm words";
+}
+
+int KenLm::Load(std::string kenlm_filename,
+                std::string symbol_table_filename,
+                util::LoadMethod load_method) {
+  if (model_ != nullptr) { delete model_; }
+  model_ = nullptr;
+  vocab_ = nullptr;
+
+  // load KenLm model
+  lm::ngram::Config config;
+  config.load_method = load_method;
+  model_ = lm::ngram::LoadVirtual(kenlm_filename.c_str(), config);
+  if (model_ == nullptr) { KALDI_ERR << "Failed to load KenLm model"; }
+
+  // KenLm holds vocabulary internally with ownership,
+  // vocab_ here is just for concise reference
+  vocab_ = &model_->BaseVocabulary();
+  if (vocab_ == nullptr) { KALDI_ERR << "Failed to get vocabulary from KenLm model"; }
+
+  // compute the index mapping from Kaldi symbol to KenLm word
+  ComputeSymbolToWordIndexMapping(symbol_table_filename);
+  return 0;
+}
+
+} // namespace kaldi
+#endif