Allow more online models to load tokens file from the memory (#1352)

Co-authored-by: xiao <shawl336@6163.com>

@@ -120,3 +120,99 @@ jobs:
           ./streaming-zipformer-buffered-tokens-hotwords-c-api
 
           rm -rf sherpa-onnx-streaming-zipformer-*
+
+      - name: Test streaming paraformer with tokens loaded from buffers
+        shell: bash
+        run: |
+          gcc -o streaming-paraformer-buffered-tokens-c-api ./c-api-examples/streaming-paraformer-buffered-tokens-c-api.c \
+            -I ./build/install/include \
+            -L ./build/install/lib/ \
+            -l sherpa-onnx-c-api \
+            -l onnxruntime
+
+          ls -lh streaming-paraformer-buffered-tokens-c-api
+
+          if [[ ${{ matrix.os }} == ubuntu-latest ]]; then
+            ldd ./streaming-paraformer-buffered-tokens-c-api
+            echo "----"
+            readelf -d ./streaming-paraformer-buffered-tokens-c-api
+          fi
+
+          curl -SL -O https://github.com/k2-fsa/sherpa-onnx/releases/download/asr-models/sherpa-onnx-streaming-paraformer-bilingual-zh-en.tar.bz2
+          tar xvf sherpa-onnx-streaming-paraformer-bilingual-zh-en.tar.bz2
+          rm sherpa-onnx-streaming-paraformer-bilingual-zh-en.tar.bz2
+
+          ls -lh sherpa-onnx-streaming-paraformer-bilingual-zh-en
+          echo "---"
+          ls -lh sherpa-onnx-streaming-paraformer-bilingual-zh-en/test_wavs
+
+          export LD_LIBRARY_PATH=$PWD/build/install/lib:$LD_LIBRARY_PATH
+          export DYLD_LIBRARY_PATH=$PWD/build/install/lib:$DYLD_LIBRARY_PATH
+
+          ./streaming-paraformer-buffered-tokens-c-api
+
+          rm -rf sherpa-onnx-streaming-paraformer-*
+
+      - name: Test streaming ctc with tokens loaded from buffers
+        shell: bash
+        run: |
+          gcc -o streaming-ctc-buffered-tokens-c-api ./c-api-examples/streaming-ctc-buffered-tokens-c-api.c \
+            -I ./build/install/include \
+            -L ./build/install/lib/ \
+            -l sherpa-onnx-c-api \
+            -l onnxruntime
+
+          ls -lh streaming-ctc-buffered-tokens-c-api
+
+          if [[ ${{ matrix.os }} == ubuntu-latest ]]; then
+            ldd ./streaming-ctc-buffered-tokens-c-api
+            echo "----"
+            readelf -d ./streaming-ctc-buffered-tokens-c-api
+          fi
+
+          curl -SL -O https://github.com/k2-fsa/sherpa-onnx/releases/download/asr-models/sherpa-onnx-streaming-zipformer-ctc-multi-zh-hans-2023-12-13.tar.bz2
+          tar xvf sherpa-onnx-streaming-zipformer-ctc-multi-zh-hans-2023-12-13.tar.bz2
+          rm sherpa-onnx-streaming-zipformer-ctc-multi-zh-hans-2023-12-13.tar.bz2
+
+          ls -lh sherpa-onnx-streaming-zipformer-ctc-multi-zh-hans-2023-12-13
+          echo "---"
+          ls -lh sherpa-onnx-streaming-zipformer-ctc-multi-zh-hans-2023-12-13/test_wavs
+
+          export LD_LIBRARY_PATH=$PWD/build/install/lib:$LD_LIBRARY_PATH
+          export DYLD_LIBRARY_PATH=$PWD/build/install/lib:$DYLD_LIBRARY_PATH
+
+          ./streaming-ctc-buffered-tokens-c-api
+
+          rm -rf sherpa-onnx-streaming-ctc-*
+
+      - name: Test keywords spotting with tokens and keywords loaded from buffers
+        shell: bash
+        run: |
+          gcc -o keywords-spotter-buffered-tokens-keywords-c-api ./c-api-examples/keywords-spotter-buffered-tokens-keywords-c-api.c \
+            -I ./build/install/include \
+            -L ./build/install/lib/ \
+            -l sherpa-onnx-c-api \
+            -l onnxruntime
+
+          ls -lh keywords-spotter-buffered-tokens-keywords-c-api
+
+          if [[ ${{ matrix.os }} == ubuntu-latest ]]; then
+            ldd ./keywords-spotter-buffered-tokens-keywords-c-api
+            echo "----"
+            readelf -d ./keywords-spotter-buffered-tokens-keywords-c-api
+          fi
+
+          curl -SL -O https://github.com/k2-fsa/sherpa-onnx/releases/download/kws-models/sherpa-onnx-kws-zipformer-wenetspeech-3.3M-2024-01-01-mobile.tar.bz2
+          tar xvf sherpa-onnx-kws-zipformer-wenetspeech-3.3M-2024-01-01-mobile.tar.bz2
+          rm sherpa-onnx-kws-zipformer-wenetspeech-3.3M-2024-01-01-mobile.tar.bz2
+
+          ls -lh sherpa-onnx-kws-zipformer-wenetspeech-3.3M-2024-01-01-mobile
+          echo "---"
+          ls -lh sherpa-onnx-kws-zipformer-wenetspeech-3.3M-2024-01-01-mobile/test_wavs
+
+          export LD_LIBRARY_PATH=$PWD/build/install/lib:$LD_LIBRARY_PATH
+          export DYLD_LIBRARY_PATH=$PWD/build/install/lib:$DYLD_LIBRARY_PATH
+
+          ./keywords-spotter-buffered-tokens-keywords-c-api
+
+          rm -rf sherpa-onnx-kws-zipformer-*
\ No newline at end of file

@@ -52,6 +52,18 @@ add_executable(streaming-zipformer-buffered-tokens-hotwords-c-api
                streaming-zipformer-buffered-tokens-hotwords-c-api.c)
 target_link_libraries(streaming-zipformer-buffered-tokens-hotwords-c-api sherpa-onnx-c-api)
 
+add_executable(streaming-paraformer-buffered-tokens-c-api
+               streaming-paraformer-buffered-tokens-c-api.c)
+target_link_libraries(streaming-paraformer-buffered-tokens-c-api sherpa-onnx-c-api)
+
+add_executable(streaming-ctc-buffered-tokens-c-api
+               streaming-ctc-buffered-tokens-c-api.c)
+target_link_libraries(streaming-ctc-buffered-tokens-c-api sherpa-onnx-c-api)
+
+add_executable(keywords-spotter-buffered-tokens-keywords-c-api
+               keywords-spotter-buffered-tokens-keywords-c-api.c)
+target_link_libraries(keywords-spotter-buffered-tokens-keywords-c-api sherpa-onnx-c-api)
+
 if(SHERPA_ONNX_HAS_ALSA)
   add_subdirectory(./asr-microphone-example)
 elseif((UNIX AND NOT APPLE) OR LINUX)

+// c-api-examples/keywords-spotter-buffered-tokens-keywords-c-api.c
+//
+// Copyright (c)  2024  Xiaomi Corporation
+// Copyright (c)  2024  Luo Xiao
+
+//
+// This file demonstrates how to use keywords spotter with sherpa-onnx's C
+// API and with tokens and keywords loaded from buffered strings instead of from
+// external files API.
+// clang-format off
+// 
+// wget https://github.com/k2-fsa/sherpa-onnx/releases/download/kws-models/sherpa-onnx-kws-zipformer-wenetspeech-3.3M-2024-01-01-mobile.tar.bz2
+// tar xvf sherpa-onnx-kws-zipformer-wenetspeech-3.3M-2024-01-01-mobile.tar.bz2
+// rm sherpa-onnx-kws-zipformer-wenetspeech-3.3M-2024-01-01-mobile.tar.bz2
+//
+// clang-format on
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include "sherpa-onnx/c-api/c-api.h"
+
+static size_t ReadFile(const char *filename, const char **buffer_out) {
+  FILE *file = fopen(filename, "r");
+  if (file == NULL) {
+    fprintf(stderr, "Failed to open %s\n", filename);
+    return -1;
+  }
+  fseek(file, 0L, SEEK_END);
+  long size = ftell(file);
+  rewind(file);
+  *buffer_out = malloc(size);
+  if (*buffer_out == NULL) {
+    fclose(file);
+    fprintf(stderr, "Memory error\n");
+    return -1;
+  }
+  size_t read_bytes = fread(*buffer_out, 1, size, file);
+  if (read_bytes != size) {
+    printf("Errors occured in reading the file %s\n", filename);
+    free((void *)*buffer_out);
+    *buffer_out = NULL;
+    fclose(file);
+    return -1;
+  }
+  fclose(file);
+  return read_bytes;
+}
+
+int32_t main() {
+  const char *wav_filename =
+      "sherpa-onnx-kws-zipformer-wenetspeech-3.3M-2024-01-01-mobile/test_wavs/"
+      "6.wav";
+  const char *encoder_filename =
+      "sherpa-onnx-kws-zipformer-wenetspeech-3.3M-2024-01-01-mobile/"
+      "encoder-epoch-12-avg-2-chunk-16-left-64.int8.onnx";
+  const char *decoder_filename =
+      "sherpa-onnx-kws-zipformer-wenetspeech-3.3M-2024-01-01-mobile/"
+      "decoder-epoch-12-avg-2-chunk-16-left-64.onnx";
+  const char *joiner_filename =
+      "sherpa-onnx-kws-zipformer-wenetspeech-3.3M-2024-01-01-mobile/"
+      "joiner-epoch-12-avg-2-chunk-16-left-64.int8.onnx";
+  const char *provider = "cpu";
+  const char *tokens_filename =
+      "sherpa-onnx-kws-zipformer-wenetspeech-3.3M-2024-01-01-mobile/tokens.txt";
+  const char *keywords_filename =
+      "sherpa-onnx-kws-zipformer-wenetspeech-3.3M-2024-01-01-mobile/test_wavs/"
+      "test_keywords.txt";
+  const SherpaOnnxWave *wave = SherpaOnnxReadWave(wav_filename);
+  if (wave == NULL) {
+    fprintf(stderr, "Failed to read %s\n", wav_filename);
+    return -1;
+  }
+
+  // reading tokens and keywords to buffers
+  const char *tokens_buf;
+  size_t token_buf_size = ReadFile(tokens_filename, &tokens_buf);
+  if (token_buf_size < 1) {
+    fprintf(stderr, "Please check your tokens.txt!\n");
+    free((void *)tokens_buf);
+    return -1;
+  }
+  const char *keywords_buf;
+  size_t keywords_buf_size = ReadFile(keywords_filename, &keywords_buf);
+  if (keywords_buf_size < 1) {
+    fprintf(stderr, "Please check your keywords.txt!\n");
+    free((void *)keywords_buf);
+    return -1;
+  }
+
+  // Zipformer config
+  SherpaOnnxOnlineTransducerModelConfig zipformer_config;
+  memset(&zipformer_config, 0, sizeof(zipformer_config));
+  zipformer_config.encoder = encoder_filename;
+  zipformer_config.decoder = decoder_filename;
+  zipformer_config.joiner = joiner_filename;
+
+  // Online model config
+  SherpaOnnxOnlineModelConfig online_model_config;
+  memset(&online_model_config, 0, sizeof(online_model_config));
+  online_model_config.debug = 1;
+  online_model_config.num_threads = 1;
+  online_model_config.provider = provider;
+  online_model_config.tokens_buf = tokens_buf;
+  online_model_config.tokens_buf_size = token_buf_size;
+  online_model_config.transducer = zipformer_config;
+
+  // Keywords-spotter config
+  SherpaOnnxKeywordSpotterConfig keywords_spotter_config;
+  memset(&keywords_spotter_config, 0, sizeof(keywords_spotter_config));
+  keywords_spotter_config.max_active_paths = 4;
+  keywords_spotter_config.keywords_threshold = 0.1;
+  keywords_spotter_config.keywords_score = 3.0;
+  keywords_spotter_config.model_config = online_model_config;
+  keywords_spotter_config.keywords_buf = keywords_buf;
+  keywords_spotter_config.keywords_buf_size = keywords_buf_size;
+
+  SherpaOnnxKeywordSpotter *keywords_spotter =
+      SherpaOnnxCreateKeywordSpotter(&keywords_spotter_config);
+
+  free((void *)tokens_buf);
+  tokens_buf = NULL;
+  free((void *)keywords_buf);
+  keywords_buf = NULL;
+
+  if (keywords_spotter == NULL) {
+    fprintf(stderr, "Please check your config!\n");
+    SherpaOnnxFreeWave(wave);
+    return -1;
+  }
+
+  SherpaOnnxOnlineStream *stream =
+      SherpaOnnxCreateKeywordStream(keywords_spotter);
+
+  const SherpaOnnxDisplay *display = SherpaOnnxCreateDisplay(50);
+  int32_t segment_id = 0;
+
+// simulate streaming. You can choose an arbitrary N
+#define N 3200
+
+  fprintf(stderr, "sample rate: %d, num samples: %d, duration: %.2f s\n",
+          wave->sample_rate, wave->num_samples,
+          (float)wave->num_samples / wave->sample_rate);
+
+  int32_t k = 0;
+  while (k < wave->num_samples) {
+    int32_t start = k;
+    int32_t end =
+        (start + N > wave->num_samples) ? wave->num_samples : (start + N);
+    k += N;
+
+    SherpaOnnxOnlineStreamAcceptWaveform(stream, wave->sample_rate,
+                                         wave->samples + start, end - start);
+    while (SherpaOnnxIsKeywordStreamReady(keywords_spotter, stream)) {
+      SherpaOnnxDecodeKeywordStream(keywords_spotter, stream);
+    }
+
+    const SherpaOnnxKeywordResult *r =
+        SherpaOnnxGetKeywordResult(keywords_spotter, stream);
+
+    if (strlen(r->keyword)) {
+      SherpaOnnxPrint(display, segment_id, r->keyword);
+    }
+
+    SherpaOnnxDestroyKeywordResult(r);
+  }
+
+  // add some tail padding
+  float tail_paddings[4800] = {0};  // 0.3 seconds at 16 kHz sample rate
+  SherpaOnnxOnlineStreamAcceptWaveform(stream, wave->sample_rate, tail_paddings,
+                                       4800);
+
+  SherpaOnnxFreeWave(wave);
+
+  SherpaOnnxOnlineStreamInputFinished(stream);
+  while (SherpaOnnxIsKeywordStreamReady(keywords_spotter, stream)) {
+    SherpaOnnxDecodeKeywordStream(keywords_spotter, stream);
+  }
+
+  const SherpaOnnxKeywordResult *r =
+      SherpaOnnxGetKeywordResult(keywords_spotter, stream);
+
+  if (strlen(r->keyword)) {
+    SherpaOnnxPrint(display, segment_id, r->keyword);
+  }
+
+  SherpaOnnxDestroyKeywordResult(r);
+
+  SherpaOnnxDestroyDisplay(display);
+  SherpaOnnxDestroyOnlineStream(stream);
+  SherpaOnnxDestroyKeywordSpotter(keywords_spotter);
+  fprintf(stderr, "\n");
+
+  return 0;
+}

+// c-api-examples/streaming-ctc-buffered-tokens-c-api.c
+//
+// Copyright (c)  2024  Xiaomi Corporation
+// Copyright (c)  2024  Luo Xiao
+
+//
+// This file demonstrates how to use streaming Zipformer2 Ctc with sherpa-onnx's
+// C API and with tokens loaded from buffered strings instead of
+// from external files API.
+// clang-format off
+// 
+// wget https://github.com/k2-fsa/sherpa-onnx/releases/download/asr-models/sherpa-onnx-streaming-zipformer-ctc-multi-zh-hans-2023-12-13.tar.bz2
+// tar xvf sherpa-onnx-streaming-zipformer-ctc-multi-zh-hans-2023-12-13.tar.bz2
+// rm sherpa-onnx-streaming-zipformer-ctc-multi-zh-hans-2023-12-13.tar.bz2
+//
+// clang-format on
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include "sherpa-onnx/c-api/c-api.h"
+
+static size_t ReadFile(const char *filename, const char **buffer_out) {
+  FILE *file = fopen(filename, "r");
+  if (file == NULL) {
+    fprintf(stderr, "Failed to open %s\n", filename);
+    return -1;
+  }
+  fseek(file, 0L, SEEK_END);
+  long size = ftell(file);
+  rewind(file);
+  *buffer_out = malloc(size);
+  if (*buffer_out == NULL) {
+    fclose(file);
+    fprintf(stderr, "Memory error\n");
+    return -1;
+  }
+  size_t read_bytes = fread(*buffer_out, 1, size, file);
+  if (read_bytes != size) {
+    printf("Errors occured in reading the file %s\n", filename);
+    free((void *)*buffer_out);
+    *buffer_out = NULL;
+    fclose(file);
+    return -1;
+  }
+  fclose(file);
+  return read_bytes;
+}
+
+int32_t main() {
+  const char *wav_filename =
+      "sherpa-onnx-streaming-zipformer-ctc-multi-zh-hans-2023-12-13/test_wavs/"
+      "DEV_T0000000000.wav";
+  const char *model_filename =
+      "sherpa-onnx-streaming-zipformer-ctc-multi-zh-hans-2023-12-13/"
+      "ctc-epoch-20-avg-1-chunk-16-left-128.int8.onnx";
+  const char *tokens_filename =
+      "sherpa-onnx-streaming-zipformer-ctc-multi-zh-hans-2023-12-13/tokens.txt";
+  const char *provider = "cpu";
+
+  const SherpaOnnxWave *wave = SherpaOnnxReadWave(wav_filename);
+  if (wave == NULL) {
+    fprintf(stderr, "Failed to read %s\n", wav_filename);
+    return -1;
+  }
+
+  // reading tokens to buffers
+  const char *tokens_buf;
+  size_t token_buf_size = ReadFile(tokens_filename, &tokens_buf);
+  if (token_buf_size < 1) {
+    fprintf(stderr, "Please check your tokens.txt!\n");
+    free((void *)tokens_buf);
+    return -1;
+  }
+
+  // Zipformer2Ctc config
+  SherpaOnnxOnlineZipformer2CtcModelConfig zipformer2_ctc_config;
+  memset(&zipformer2_ctc_config, 0, sizeof(zipformer2_ctc_config));
+  zipformer2_ctc_config.model = model_filename;
+
+  // Online model config
+  SherpaOnnxOnlineModelConfig online_model_config;
+  memset(&online_model_config, 0, sizeof(online_model_config));
+  online_model_config.debug = 1;
+  online_model_config.num_threads = 1;
+  online_model_config.provider = provider;
+  online_model_config.tokens_buf = tokens_buf;
+  online_model_config.tokens_buf_size = token_buf_size;
+  online_model_config.zipformer2_ctc = zipformer2_ctc_config;
+
+  // Recognizer config
+  SherpaOnnxOnlineRecognizerConfig recognizer_config;
+  memset(&recognizer_config, 0, sizeof(recognizer_config));
+  recognizer_config.decoding_method = "greedy_search";
+  recognizer_config.model_config = online_model_config;
+
+  SherpaOnnxOnlineRecognizer *recognizer =
+      SherpaOnnxCreateOnlineRecognizer(&recognizer_config);
+
+  free((void *)tokens_buf);
+  tokens_buf = NULL;
+
+  if (recognizer == NULL) {
+    fprintf(stderr, "Please check your config!\n");
+    SherpaOnnxFreeWave(wave);
+    return -1;
+  }
+
+  SherpaOnnxOnlineStream *stream = SherpaOnnxCreateOnlineStream(recognizer);
+
+  const SherpaOnnxDisplay *display = SherpaOnnxCreateDisplay(50);
+  int32_t segment_id = 0;
+
+// simulate streaming. You can choose an arbitrary N
+#define N 3200
+
+  fprintf(stderr, "sample rate: %d, num samples: %d, duration: %.2f s\n",
+          wave->sample_rate, wave->num_samples,
+          (float)wave->num_samples / wave->sample_rate);
+
+  int32_t k = 0;
+  while (k < wave->num_samples) {
+    int32_t start = k;
+    int32_t end =
+        (start + N > wave->num_samples) ? wave->num_samples : (start + N);
+    k += N;
+
+    SherpaOnnxOnlineStreamAcceptWaveform(stream, wave->sample_rate,
+                                         wave->samples + start, end - start);
+    while (SherpaOnnxIsOnlineStreamReady(recognizer, stream)) {
+      SherpaOnnxDecodeOnlineStream(recognizer, stream);
+    }
+
+    const SherpaOnnxOnlineRecognizerResult *r =
+        SherpaOnnxGetOnlineStreamResult(recognizer, stream);
+
+    if (strlen(r->text)) {
+      SherpaOnnxPrint(display, segment_id, r->text);
+    }
+
+    if (SherpaOnnxOnlineStreamIsEndpoint(recognizer, stream)) {
+      if (strlen(r->text)) {
+        ++segment_id;
+      }
+      SherpaOnnxOnlineStreamReset(recognizer, stream);
+    }
+
+    SherpaOnnxDestroyOnlineRecognizerResult(r);
+  }
+
+  // add some tail padding
+  float tail_paddings[4800] = {0};  // 0.3 seconds at 16 kHz sample rate
+  SherpaOnnxOnlineStreamAcceptWaveform(stream, wave->sample_rate, tail_paddings,
+                                       4800);
+
+  SherpaOnnxFreeWave(wave);
+
+  SherpaOnnxOnlineStreamInputFinished(stream);
+  while (SherpaOnnxIsOnlineStreamReady(recognizer, stream)) {
+    SherpaOnnxDecodeOnlineStream(recognizer, stream);
+  }
+
+  const SherpaOnnxOnlineRecognizerResult *r =
+      SherpaOnnxGetOnlineStreamResult(recognizer, stream);
+
+  if (strlen(r->text)) {
+    SherpaOnnxPrint(display, segment_id, r->text);
+  }
+
+  SherpaOnnxDestroyOnlineRecognizerResult(r);
+
+  SherpaOnnxDestroyDisplay(display);
+  SherpaOnnxDestroyOnlineStream(stream);
+  SherpaOnnxDestroyOnlineRecognizer(recognizer);
+  fprintf(stderr, "\n");
+
+  return 0;
+}

+// c-api-examples/streaming-paraformer-buffered-tokens-c-api.c
+//
+// Copyright (c)  2024  Xiaomi Corporation
+// Copyright (c)  2024  Luo Xiao
+
+//
+// This file demonstrates how to use streaming Paraformer with sherpa-onnx's C
+// API and with tokens loaded from buffered strings instead of from
+// external files API.
+// clang-format off
+// 
+// wget https://github.com/k2-fsa/sherpa-onnx/releases/download/asr-models/sherpa-onnx-streaming-paraformer-bilingual-zh-en.tar.bz2
+// tar xvf sherpa-onnx-streaming-paraformer-bilingual-zh-en.tar.bz2
+// rm sherpa-onnx-streaming-paraformer-bilingual-zh-en.tar.bz2
+//
+// clang-format on
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include "sherpa-onnx/c-api/c-api.h"
+
+static size_t ReadFile(const char *filename, const char **buffer_out) {
+  FILE *file = fopen(filename, "r");
+  if (file == NULL) {
+    fprintf(stderr, "Failed to open %s\n", filename);
+    return -1;
+  }
+  fseek(file, 0L, SEEK_END);
+  long size = ftell(file);
+  rewind(file);
+  *buffer_out = malloc(size);
+  if (*buffer_out == NULL) {
+    fclose(file);
+    fprintf(stderr, "Memory error\n");
+    return -1;
+  }
+  size_t read_bytes = fread(*buffer_out, 1, size, file);
+  if (read_bytes != size) {
+    printf("Errors occured in reading the file %s\n", filename);
+    free((void *)*buffer_out);
+    *buffer_out = NULL;
+    fclose(file);
+    return -1;
+  }
+  fclose(file);
+  return read_bytes;
+}
+
+int32_t main() {
+  const char *wav_filename =
+      "sherpa-onnx-streaming-paraformer-bilingual-zh-en/test_wavs/0.wav";
+  const char *encoder_filename =
+      "sherpa-onnx-streaming-paraformer-bilingual-zh-en/encoder.int8.onnx";
+  const char *decoder_filename =
+      "sherpa-onnx-streaming-paraformer-bilingual-zh-en/decoder.int8.onnx";
+  const char *tokens_filename =
+      "sherpa-onnx-streaming-paraformer-bilingual-zh-en/tokens.txt";
+  const char *provider = "cpu";
+
+  const SherpaOnnxWave *wave = SherpaOnnxReadWave(wav_filename);
+  if (wave == NULL) {
+    fprintf(stderr, "Failed to read %s\n", wav_filename);
+    return -1;
+  }
+
+  // reading tokens to buffers
+  const char *tokens_buf;
+  size_t token_buf_size = ReadFile(tokens_filename, &tokens_buf);
+  if (token_buf_size < 1) {
+    fprintf(stderr, "Please check your tokens.txt!\n");
+    free((void *)tokens_buf);
+    return -1;
+  }
+
+  // Paraformer config
+  SherpaOnnxOnlineParaformerModelConfig paraformer_config;
+  memset(&paraformer_config, 0, sizeof(paraformer_config));
+  paraformer_config.encoder = encoder_filename;
+  paraformer_config.decoder = decoder_filename;
+
+  // Online model config
+  SherpaOnnxOnlineModelConfig online_model_config;
+  memset(&online_model_config, 0, sizeof(online_model_config));
+  online_model_config.debug = 1;
+  online_model_config.num_threads = 1;
+  online_model_config.provider = provider;
+  online_model_config.tokens_buf = tokens_buf;
+  online_model_config.tokens_buf_size = token_buf_size;
+  online_model_config.paraformer = paraformer_config;
+
+  // Recognizer config
+  SherpaOnnxOnlineRecognizerConfig recognizer_config;
+  memset(&recognizer_config, 0, sizeof(recognizer_config));
+  recognizer_config.decoding_method = "greedy_search";
+  recognizer_config.model_config = online_model_config;
+
+  SherpaOnnxOnlineRecognizer *recognizer =
+      SherpaOnnxCreateOnlineRecognizer(&recognizer_config);
+
+  free((void *)tokens_buf);
+  tokens_buf = NULL;
+
+  if (recognizer == NULL) {
+    fprintf(stderr, "Please check your config!\n");
+    SherpaOnnxFreeWave(wave);
+    return -1;
+  }
+
+  SherpaOnnxOnlineStream *stream = SherpaOnnxCreateOnlineStream(recognizer);
+
+  const SherpaOnnxDisplay *display = SherpaOnnxCreateDisplay(50);
+  int32_t segment_id = 0;
+
+// simulate streaming. You can choose an arbitrary N
+#define N 3200
+
+  fprintf(stderr, "sample rate: %d, num samples: %d, duration: %.2f s\n",
+          wave->sample_rate, wave->num_samples,
+          (float)wave->num_samples / wave->sample_rate);
+
+  int32_t k = 0;
+  while (k < wave->num_samples) {
+    int32_t start = k;
+    int32_t end =
+        (start + N > wave->num_samples) ? wave->num_samples : (start + N);
+    k += N;
+
+    SherpaOnnxOnlineStreamAcceptWaveform(stream, wave->sample_rate,
+                                         wave->samples + start, end - start);
+    while (SherpaOnnxIsOnlineStreamReady(recognizer, stream)) {
+      SherpaOnnxDecodeOnlineStream(recognizer, stream);
+    }
+
+    const SherpaOnnxOnlineRecognizerResult *r =
+        SherpaOnnxGetOnlineStreamResult(recognizer, stream);
+
+    if (strlen(r->text)) {
+      SherpaOnnxPrint(display, segment_id, r->text);
+    }
+
+    if (SherpaOnnxOnlineStreamIsEndpoint(recognizer, stream)) {
+      if (strlen(r->text)) {
+        ++segment_id;
+      }
+      SherpaOnnxOnlineStreamReset(recognizer, stream);
+    }
+
+    SherpaOnnxDestroyOnlineRecognizerResult(r);
+  }
+
+  // add some tail padding
+  float tail_paddings[4800] = {0};  // 0.3 seconds at 16 kHz sample rate
+  SherpaOnnxOnlineStreamAcceptWaveform(stream, wave->sample_rate, tail_paddings,
+                                       4800);
+
+  SherpaOnnxFreeWave(wave);
+
+  SherpaOnnxOnlineStreamInputFinished(stream);
+  while (SherpaOnnxIsOnlineStreamReady(recognizer, stream)) {
+    SherpaOnnxDecodeOnlineStream(recognizer, stream);
+  }
+
+  const SherpaOnnxOnlineRecognizerResult *r =
+      SherpaOnnxGetOnlineStreamResult(recognizer, stream);
+
+  if (strlen(r->text)) {
+    SherpaOnnxPrint(display, segment_id, r->text);
+  }
+
+  SherpaOnnxDestroyOnlineRecognizerResult(r);
+
+  SherpaOnnxDestroyDisplay(display);
+  SherpaOnnxDestroyOnlineStream(stream);
+  SherpaOnnxDestroyOnlineRecognizer(recognizer);
+  fprintf(stderr, "\n");
+
+  return 0;
+}

@@ -5,7 +5,7 @@
 
 //
 // This file demonstrates how to use streaming Zipformer with sherpa-onnx's C
-// and with tokens and hotwords loaded from buffered strings instead of from
+// API and with tokens and hotwords loaded from buffered strings instead of from
 // external files API.
 // clang-format off
 // 

@@ -667,6 +667,12 @@ SherpaOnnxKeywordSpotter *SherpaOnnxCreateKeywordSpotter(
 
   spotter_config.model_config.tokens =
       SHERPA_ONNX_OR(config->model_config.tokens, "");
+  if (config->model_config.tokens_buf &&
+      config->model_config.tokens_buf_size > 0) {
+    spotter_config.model_config.tokens_buf = std::string(
+        config->model_config.tokens_buf, config->model_config.tokens_buf_size);
+  }
+
   spotter_config.model_config.num_threads =
       SHERPA_ONNX_OR(config->model_config.num_threads, 1);
   spotter_config.model_config.provider_config.provider =
@@ -691,6 +697,10 @@ SherpaOnnxKeywordSpotter *SherpaOnnxCreateKeywordSpotter(
       SHERPA_ONNX_OR(config->keywords_threshold, 0.25);
 
   spotter_config.keywords_file = SHERPA_ONNX_OR(config->keywords_file, "");
+  if (config->keywords_buf && config->keywords_buf_size > 0) {
+    spotter_config.keywords_buf =
+        std::string(config->keywords_buf, config->keywords_buf_size);
+  }
 
   if (config->model_config.debug) {
     SHERPA_ONNX_LOGE("%s\n", spotter_config.ToString().c_str());

@@ -88,8 +88,8 @@ SHERPA_ONNX_API typedef struct SherpaOnnxOnlineModelConfig {
   //  - cjkchar+bpe
   const char *modeling_unit;
   const char *bpe_vocab;
-  /// if non-null, loading the tokens from the buffered string directly in
-  /// prioriy
+  /// if non-null, loading the tokens from the buffer instead of from the
+  /// "tokens" file
   const char *tokens_buf;
   /// byte size excluding the trailing '\0'
   int32_t tokens_buf_size;
@@ -637,6 +637,11 @@ SHERPA_ONNX_API typedef struct SherpaOnnxKeywordSpotterConfig {
   float keywords_score;
   float keywords_threshold;
   const char *keywords_file;
+  /// if non-null, loading the keywords from the buffer instead of from the
+  /// keywords_file
+  const char *keywords_buf;
+  /// byte size excluding the trailing '\0'
+  int32_t keywords_buf_size;
 } SherpaOnnxKeywordSpotterConfig;
 
 SHERPA_ONNX_API typedef struct SherpaOnnxKeywordSpotter

@@ -66,15 +66,25 @@ class KeywordSpotterTransducerImpl : public KeywordSpotterImpl {
  public:
   explicit KeywordSpotterTransducerImpl(const KeywordSpotterConfig &config)
       : config_(config),
-        model_(OnlineTransducerModel::Create(config.model_config)),
-        sym_(config.model_config.tokens) {
+        model_(OnlineTransducerModel::Create(config.model_config)) {
+    if (!config.model_config.tokens_buf.empty()) {
+      sym_ = SymbolTable(config.model_config.tokens_buf, false);
+    } else {
+      /// assuming tokens_buf and tokens are guaranteed not being both empty
+      sym_ = SymbolTable(config.model_config.tokens, true);
+    }
+
     if (sym_.Contains("<unk>")) {
       unk_id_ = sym_["<unk>"];
     }
 
     model_->SetFeatureDim(config.feat_config.feature_dim);
 
-    InitKeywords();
+    if (config.keywords_buf.empty()) {
+      InitKeywords();
+    } else {
+      InitKeywordsFromBufStr();
+    }
 
     decoder_ = std::make_unique<TransducerKeywordDecoder>(
         model_.get(), config_.max_active_paths, config_.num_trailing_blanks,
@@ -305,6 +315,12 @@ class KeywordSpotterTransducerImpl : public KeywordSpotterImpl {
   }
 #endif
 
+  void InitKeywordsFromBufStr() {
+    // keywords_buf's content is supposed to be same as the keywords_file's
+    std::istringstream is(config_.keywords_buf);
+    InitKeywords(is);
+  }
+
   void InitOnlineStream(OnlineStream *stream) const {
     auto r = decoder_->GetEmptyResult();
     SHERPA_ONNX_CHECK_EQ(r.hyps.Size(), 1);

@@ -89,8 +89,17 @@ void KeywordSpotterConfig::Register(ParseOptions *po) {
 }
 
 bool KeywordSpotterConfig::Validate() const {
-  if (keywords_file.empty()) {
-    SHERPA_ONNX_LOGE("Please provide --keywords-file.");
+  if (!keywords_file.empty() && !keywords_buf.empty()) {
+    SHERPA_ONNX_LOGE(
+        "you can not provide a keywords_buf and a keywords file: '%s', "
+        "at the same time, which is confusing",
+        keywords_file.c_str());
+    return false;
+  }
+
+  if (keywords_file.empty() && keywords_buf.empty()) {
+    SHERPA_ONNX_LOGE(
+        "Please provide either a keywords-file or the keywords-buf");
     return false;
   }
 
@@ -99,7 +108,7 @@ bool KeywordSpotterConfig::Validate() const {
   // keywords file will be packaged into the sherpa-onnx-wasm-kws-main.data file
   // Solution: take keyword_file variable is directly
   // parsed as a string of keywords
-  if (!std::ifstream(keywords_file.c_str()).good()) {
+  if (keywords_buf.empty() && !std::ifstream(keywords_file.c_str()).good()) {
     SHERPA_ONNX_LOGE("Keywords file '%s' does not exist.",
                      keywords_file.c_str());
     return false;

@@ -69,6 +69,11 @@ struct KeywordSpotterConfig {
 
   std::string keywords_file;
 
+  /// if keywords_buf is non-empty,
+  /// the keywords will be loaded from the buffer instead of from the
+  /// "keywrods_file"
+  std::string keywords_buf;
+
   KeywordSpotterConfig() = default;
 
   KeywordSpotterConfig(const FeatureExtractorConfig &feat_config,

@@ -46,8 +46,8 @@ struct OnlineModelConfig {
   std::string bpe_vocab;
 
   /// if tokens_buf is non-empty,
-  /// the tokens will be loaded from the buffered string instead of from the
-  /// ${tokens} file
+  /// the tokens will be loaded from the buffer instead of from the
+  /// "tokens" file
   std::string tokens_buf;
 
   OnlineModelConfig() = default;

@@ -71,8 +71,14 @@ class OnlineRecognizerCtcImpl : public OnlineRecognizerImpl {
       : OnlineRecognizerImpl(config),
         config_(config),
         model_(OnlineCtcModel::Create(config.model_config)),
-        sym_(config.model_config.tokens),
         endpoint_(config_.endpoint_config) {
+    if (!config.model_config.tokens_buf.empty()) {
+      sym_ = SymbolTable(config.model_config.tokens_buf, false);
+    } else {
+      /// assuming tokens_buf and tokens are guaranteed not being both empty
+      sym_ = SymbolTable(config.model_config.tokens, true);
+    }
+
     if (!config.model_config.wenet_ctc.model.empty()) {
       // WeNet CTC models assume input samples are in the range
       // [-32768, 32767], so we set normalize_samples to false

@@ -99,8 +99,14 @@ class OnlineRecognizerParaformerImpl : public OnlineRecognizerImpl {
       : OnlineRecognizerImpl(config),
         config_(config),
         model_(config.model_config),
-        sym_(config.model_config.tokens),
         endpoint_(config_.endpoint_config) {
+    if (!config.model_config.tokens_buf.empty()) {
+      sym_ = SymbolTable(config.model_config.tokens_buf, false);
+    } else {
+      /// assuming tokens_buf and tokens are guaranteed not being both empty
+      sym_ = SymbolTable(config.model_config.tokens, true);
+    }
+
     if (config.decoding_method != "greedy_search") {
       SHERPA_ONNX_LOGE(
           "Unsupported decoding method: %s. Support only greedy_search at "

@@ -107,8 +107,8 @@ struct OnlineRecognizerConfig {
   std::string rule_fars;
 
   /// used only for modified_beam_search, if hotwords_buf is non-empty,
-  /// the hotwords will be loaded from the buffered string instead of from
-  /// ${hotwords_file}
+  /// the hotwords will be loaded from the buffered string instead of from the
+  /// "hotwords_file"
   std::string hotwords_buf;
 
   OnlineRecognizerConfig() = default;