From cc277d091e27fc8676f8e6c3dc22a198a4f659c8 Mon Sep 17 00:00:00 2001
From: Hui Zhang <zhtclz@foxmail.com>
Date: Fri, 1 Jul 2022 11:00:51 +0000
Subject: [PATCH] add backends

---
 paddlespeech/audio/backends/no_backend.py     | 27 ++++++
 paddlespeech/audio/backends/sox_io_backend.py | 28 ++++++
 paddlespeech/audio/backends/utils.py          | 89 +++++++++++++++++++
 3 files changed, 144 insertions(+)
 create mode 100644 paddlespeech/audio/backends/no_backend.py
 create mode 100644 paddlespeech/audio/backends/sox_io_backend.py
 create mode 100644 paddlespeech/audio/backends/utils.py

diff --git a/paddlespeech/audio/backends/no_backend.py b/paddlespeech/audio/backends/no_backend.py
new file mode 100644
index 000000000..78094b157
--- /dev/null
+++ b/paddlespeech/audio/backends/no_backend.py
@@ -0,0 +1,27 @@
+from pathlib import Path
+from typing import Callable
+from typing import Optional
+from typing import Tuple
+from typing import Union
+
+from paddle import Tensor
+
+
+def load(
+    filepath: Union[str, Path],
+    out: Optional[Tensor] = None,
+    normalization: Union[bool, float, Callable] = True,
+    channels_first: bool = True,
+    num_frames: int = 0,
+    offset: int = 0,
+    filetype: Optional[str] = None,
+) -> Tuple[Tensor, int]:
+    raise RuntimeError("No audio I/O backend is available.")
+
+
+def save(filepath: str, src: Tensor, sample_rate: int, precision: int = 16, channels_first: bool = True) -> None:
+    raise RuntimeError("No audio I/O backend is available.")
+
+
+def info(filepath: str) -> None:
+    raise RuntimeError("No audio I/O backend is available.")
\ No newline at end of file
diff --git a/paddlespeech/audio/backends/sox_io_backend.py b/paddlespeech/audio/backends/sox_io_backend.py
new file mode 100644
index 000000000..5a2595b3b
--- /dev/null
+++ b/paddlespeech/audio/backends/sox_io_backend.py
@@ -0,0 +1,28 @@
+
+from pathlib import Path
+from typing import Callable
+from typing import Optional
+from typing import Tuple
+from typing import Union
+
+from paddle import Tensor
+
+
+def load(
+    filepath: Union[str, Path],
+    out: Optional[Tensor] = None,
+    normalization: Union[bool, float, Callable] = True,
+    channels_first: bool = True,
+    num_frames: int = 0,
+    offset: int = 0,
+    filetype: Optional[str] = None,
+) -> Tuple[Tensor, int]:
+    raise RuntimeError("No audio I/O backend is available.")
+
+
+def save(filepath: str, src: Tensor, sample_rate: int, precision: int = 16, channels_first: bool = True) -> None:
+    raise RuntimeError("No audio I/O backend is available.")
+
+
+def info(filepath: str) -> None:
+    raise RuntimeError("No audio I/O backend is available.")
\ No newline at end of file
diff --git a/paddlespeech/audio/backends/utils.py b/paddlespeech/audio/backends/utils.py
new file mode 100644
index 000000000..ce21e0203
--- /dev/null
+++ b/paddlespeech/audio/backends/utils.py
@@ -0,0 +1,89 @@
+"""Defines utilities for switching audio backends"""
+import warnings
+from typing import List
+from typing import Optional
+
+import paddlespeech.audio
+from paddlespeech.audio._internal import module_utils as _mod_utils
+
+from . import no_backend, soundfile_backend, sox_io_backend
+
+__all__ = [
+    "list_audio_backends",
+    "get_audio_backend",
+    "set_audio_backend",
+]
+
+
+def list_audio_backends() -> List[str]:
+    """List available backends
+
+    Returns:
+        List[str]: The list of available backends.
+    """
+    backends = []
+    if _mod_utils.is_module_available("soundfile"):
+        backends.append("soundfile")
+    if _mod_utils.is_sox_available():
+        backends.append("sox_io")
+    return backends
+
+
+def set_audio_backend(backend: Optional[str]):
+    """Set the backend for I/O operation
+
+    Args:
+        backend (str or None): Name of the backend.
+            One of ``"sox_io"`` or ``"soundfile"`` based on availability
+            of the system. If ``None`` is provided the  current backend is unassigned.
+    """
+    if backend is not None and backend not in list_audio_backends():
+        raise RuntimeError(f'Backend "{backend}" is not one of ' f"available backends: {list_audio_backends()}.")
+
+    if backend is None:
+        module = no_backend
+    elif backend == "sox_io":
+        module = sox_io_backend
+    elif backend == "soundfile":
+        module = soundfile_backend
+    else:
+        raise NotImplementedError(f'Unexpected backend "{backend}"')
+
+    for func in ["save", "load", "info"]:
+        setattr(paddlespeech.audio, func, getattr(module, func))
+
+
+# def _init_audio_backend():
+#     backends = list_audio_backends()
+#     if "sox_io" in backends:
+#         set_audio_backend("sox_io")
+#     elif "soundfile" in backends:
+#         set_audio_backend("soundfile")
+#     else:
+#         warnings.warn("No audio backend is available.")
+#         set_audio_backend(None)
+
+
+def _init_audio_backend():
+    backends = list_audio_backends()
+    if "soundfile" in backends:
+        set_audio_backend("soundfile")
+    elif "sox_io" in backends:
+        set_audio_backend("sox_io")
+    else:
+        warnings.warn("No audio backend is available.")
+        set_audio_backend(None)
+
+def get_audio_backend() -> Optional[str]:
+    """Get the name of the current backend
+
+    Returns:
+        Optional[str]: The name of the current backend or ``None`` if no backend is assigned.
+    """
+    if paddlespeech.audio.load == no_backend.load:
+        return None
+    if paddlespeech.audio.load == sox_io_backend.load:
+        return "sox_io"
+    if paddlespeech.audio.load == soundfile_backend.load:
+        return "soundfile"
+    raise ValueError("Unknown backend.")
\ No newline at end of file