decoder for open vocabulary keyword spotting (#505)

* various fixes to ContextGraph to support open vocabulary keywords decoder

* Add keyword spotter runtime

* Add binary

* First version works

* Minor fixes

* update text2token

* default values

* Add jni for kws

* add kws android project

* Minor fixes

* Remove unused interface

* Minor fixes

* Add workflow

* handle extra info in texts

* Minor fixes

* Add more comments

* Fix ci

* fix cpp style

* Add input box in android demo so that users can specify their keywords

* Fix cpp style

* Fix comments

* Minor fixes

* Minor fixes

* minor fixes

* Minor fixes

* Minor fixes

* Add CI

* Fix code style

* cpplint

* Fix comments

* Fix error

sherpa-onnx/csrc/CMakeLists.txt

@@ -19,6 +19,8 @@ set(sources
   features.cc
   file-utils.cc
   hypothesis.cc
+  keyword-spotter-impl.cc
+  keyword-spotter.cc
   offline-ctc-fst-decoder-config.cc
   offline-ctc-fst-decoder.cc
   offline-ctc-greedy-search-decoder.cc
@@ -87,6 +89,7 @@ set(sources
   stack.cc
   symbol-table.cc
   text-utils.cc
+  transducer-keyword-decoder.cc
   transpose.cc
   unbind.cc
   utils.cc
@@ -173,12 +176,14 @@ if(NOT BUILD_SHARED_LIBS AND CMAKE_SYSTEM_NAME STREQUAL Linux)
 endif()
 
 add_executable(sherpa-onnx sherpa-onnx.cc)
+add_executable(sherpa-onnx-keyword-spotter sherpa-onnx-keyword-spotter.cc)
 add_executable(sherpa-onnx-offline sherpa-onnx-offline.cc)
 add_executable(sherpa-onnx-offline-parallel sherpa-onnx-offline-parallel.cc)
 add_executable(sherpa-onnx-offline-tts sherpa-onnx-offline-tts.cc)
 
 set(main_exes
   sherpa-onnx
+  sherpa-onnx-keyword-spotter
   sherpa-onnx-offline
   sherpa-onnx-offline-parallel
   sherpa-onnx-offline-tts