files / lycoris /kohya_utils.py
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# part of https://github.com/kohya-ss/sd-scripts/blob/main/library/train_util.py
import hashlib
import safetensors
from io import BytesIO
def addnet_hash_legacy(b):
"""Old model hash used by sd-webui-additional-networks for .safetensors format files"""
m = hashlib.sha256()
b.seek(0x100000)
m.update(b.read(0x10000))
return m.hexdigest()[0:8]
def addnet_hash_safetensors(b):
"""New model hash used by sd-webui-additional-networks for .safetensors format files"""
hash_sha256 = hashlib.sha256()
blksize = 1024 * 1024
b.seek(0)
header = b.read(8)
n = int.from_bytes(header, "little")
offset = n + 8
b.seek(offset)
for chunk in iter(lambda: b.read(blksize), b""):
hash_sha256.update(chunk)
return hash_sha256.hexdigest()
def precalculate_safetensors_hashes(tensors, metadata):
"""Precalculate the model hashes needed by sd-webui-additional-networks to
save time on indexing the model later."""
# Because writing user metadata to the file can change the result of
# sd_models.model_hash(), only retain the training metadata for purposes of
# calculating the hash, as they are meant to be immutable
metadata = {k: v for k, v in metadata.items() if k.startswith("ss_")}
bytes = safetensors.torch.save(tensors, metadata)
b = BytesIO(bytes)
model_hash = addnet_hash_safetensors(b)
legacy_hash = addnet_hash_legacy(b)
return model_hash, legacy_hash