Don't redownload voice files if sha256 sum matches

mimic3-tts/mimic3_tts/utils.py

@@ -13,6 +13,11 @@
 # You should have received a copy of the GNU Affero General Public License
 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
 #
+"""Utility methods for Mimic 3"""
+import hashlib
+import re
+import typing
+
 import numpy as np
 
 
@@ -24,3 +29,35 @@ def audio_float_to_int16(
     audio_norm = np.clip(audio_norm, -max_wav_value, max_wav_value)
     audio_norm = audio_norm.astype("int16")
     return audio_norm
+
+
+def wildcard_to_regex(template: str, wildcard: str = "*") -> re.Pattern:
+    """Convert a string with wildcards into a regex pattern"""
+    wildcard_escaped = re.escape(wildcard)
+
+    pattern_parts = ["^"]
+    for i, template_part in enumerate(re.split(f"({wildcard_escaped})", template)):
+        if (i % 2) == 0:
+            # Fixed string
+            pattern_parts.append(re.escape(template_part))
+        else:
+            # Wildcard separator
+            pattern_parts.append(".*")
+
+    pattern_parts.append("$")
+    pattern_str = "".join(pattern_parts)
+
+    return re.compile(pattern_str)
+
+
+def file_sha256_sum(fp: typing.BinaryIO, block_bytes: int = 4096) -> str:
+    """Return the sha256 sum of a (possibly large) file"""
+    current_hash = hashlib.sha256()
+
+    # Read in blocks in case file is very large
+    block = fp.read(block_bytes)
+    while len(block) > 0:
+        current_hash.update(block)
+        block = fp.read(block_bytes)
+
+    return current_hash.hexdigest()