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SikongJueluo
ddb8cff6a9
Introduce hash_codec module providing bidirectional encoding/decoding: - bits_tensor_to_hash_bytes / hash_bytes_to_bits_array - bits_tensor_to_cam_row - hash_bytes_to_cam_row / cam_row_to_hash_bytes
63 lines
2.0 KiB
Python
63 lines
2.0 KiB
Python
from __future__ import annotations
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import numpy as np
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import torch
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DEFAULT_HASH_WIDTH = 512
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def _validate_width(width: int) -> None:
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if width <= 0:
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raise ValueError("width must be greater than 0")
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if width % 8 != 0:
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raise ValueError("width must be divisible by 8")
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def _expected_byte_length(width: int) -> int:
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_validate_width(width)
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return width // 8
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def bits_tensor_to_hash_bytes(bits: torch.Tensor, *, width: int = 512) -> bytes:
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_validate_width(width)
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flat = bits.detach().cpu().flatten()
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if flat.numel() != width:
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raise ValueError(
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f"Input tensor must have exactly {width} values, got {flat.numel()}"
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)
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bit_array = (flat.numpy() > 0).astype(np.uint8)
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return np.packbits(bit_array).tobytes()
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def hash_bytes_to_bits_array(hash_bytes: bytes, *, width: int = 512) -> np.ndarray:
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expected = _expected_byte_length(width)
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if len(hash_bytes) != expected:
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raise ValueError(
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f"hash_bytes must be exactly {expected} bytes, got {len(hash_bytes)}"
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)
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byte_array = np.frombuffer(hash_bytes, dtype=np.uint8)
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return np.unpackbits(byte_array)[:width].astype(np.uint8, copy=False)
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def hash_bytes_to_cam_row(hash_bytes: bytes, *, width: int = 512) -> int:
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expected = _expected_byte_length(width)
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if len(hash_bytes) != expected:
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raise ValueError(
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f"hash_bytes must be exactly {expected} bytes, got {len(hash_bytes)}"
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)
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return int.from_bytes(hash_bytes, byteorder="big", signed=False)
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def cam_row_to_hash_bytes(cam_row: int, *, width: int = 512) -> bytes:
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if not (0 <= cam_row < 1 << width):
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raise ValueError(
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f"cam_row {cam_row} is out of range [0, 2**{width})"
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)
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expected = _expected_byte_length(width)
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return int(cam_row).to_bytes(expected, byteorder="big", signed=False)
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def bits_tensor_to_cam_row(bits: torch.Tensor, *, width: int = 512) -> int:
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hash_bytes = bits_tensor_to_hash_bytes(bits, width=width)
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return hash_bytes_to_cam_row(hash_bytes, width=width)
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