Hash Conversion and Serialization

def hex_to_hash(hexstr):
    """
    Convert a stored hash (hex string) back to ImageHash object.
    
    Assumes hashes are bidimensional arrays with dimensions hash_size * hash_size,
    or onedimensional arrays with dimensions binbits * 14.
    
    Args:
        hexstr (str): Hexadecimal string representation of hash
    
    Returns:
        ImageHash: Restored hash object
    
    Note:
        Does not work for hash_size < 2
    """

from PIL import Image
import imagehash

# Generate a hash
original_hash = imagehash.phash(Image.open('image.jpg'))
print(f"Original: {original_hash}")

# Convert to string for storage
hash_string = str(original_hash)
print(f"String: {hash_string}")

# Restore from string
restored_hash = imagehash.hex_to_hash(hash_string)
print(f"Restored: {restored_hash}")

# Verify they're identical
assert restored_hash == original_hash
assert str(restored_hash) == hash_string

def hex_to_flathash(hexstr, hashsize):
    """
    Convert hex string to ImageHash for flat array hashes (colorhash).
    
    Args:
        hexstr (str): Hexadecimal string representation
        hashsize (int): Hash size parameter used in original colorhash
    
    Returns:
        ImageHash: Restored hash object for colorhash
    """

# Generate a color hash
original_hash = imagehash.colorhash(Image.open('image.jpg'), binbits=3)
hash_string = str(original_hash)

# Restore colorhash (note: need to specify binbits * 14 as hashsize)
hashsize = 3 * 14  # binbits * (2 + 12) - colorhash produces 14 segments
restored_hash = imagehash.hex_to_flathash(hash_string, hashsize)

assert restored_hash == original_hash

def hex_to_multihash(hexstr):
    """
    Convert a stored multihash (hex string) back to ImageMultiHash object.
    
    Based on hex_to_hash with same limitations:
    - Assumes bidimensional arrays with hash_size * hash_size dimensions
    - Does not work for hash_size < 2
    
    Args:
        hexstr (str): Comma-separated hex string representation
    
    Returns:
        ImageMultiHash: Restored multi-hash object
    """

# Generate crop-resistant hash
original_hash = imagehash.crop_resistant_hash(
    Image.open('image.jpg'),
    min_segment_size=500,
    segmentation_image_size=1000
)

# Convert to string
hash_string = str(original_hash)
print(f"Multi-hash: {hash_string}")  # Comma-separated hashes

# Restore from string
restored_hash = imagehash.hex_to_multihash(hash_string)

assert restored_hash == original_hash
assert str(restored_hash) == hash_string

def old_hex_to_hash(hexstr, hash_size=8):
    """
    Convert old format hash string to ImageHash object.
    
    For hashes generated by ImageHash up to version 3.7.
    For newer versions, use hex_to_hash instead.
    
    Args:
        hexstr (str): Hexadecimal string in old format
        hash_size (int): Hash size used when generating (default: 8)
    
    Returns:
        ImageHash: Restored hash object
    
    Raises:
        ValueError: If hex string size doesn't match expected count
    """

# Example hash string for 8x8 hash
"ffd7918181c9ffff"  # 16 hex characters = 64 bits = 8x8 hash

# Example multi-hash string
"ffd7918181c9ffff,7f7f7f7f7f7f7f7f,0f0f0f0f0f0f0f0f"  # 3 segment hashes

# Color hash with binbits=3 has 14 * 3 = 42 bits
# Represented as 11 hex characters (44 bits, with 2 padding bits)
"7ff3e1c8764"

import sqlite3
from PIL import Image
import imagehash

# Setup database
conn = sqlite3.connect('image_hashes.db')
cursor = conn.cursor()
cursor.execute('''
    CREATE TABLE IF NOT EXISTS images (
        id INTEGER PRIMARY KEY,
        filename TEXT,
        ahash TEXT,
        phash TEXT,
        dhash TEXT
    )
''')

# Store hashes
image = Image.open('photo.jpg')
cursor.execute('''
    INSERT INTO images (filename, ahash, phash, dhash) 
    VALUES (?, ?, ?, ?)
''', (
    'photo.jpg',
    str(imagehash.average_hash(image)),
    str(imagehash.phash(image)),
    str(imagehash.dhash(image))
))

# Retrieve and restore hashes
cursor.execute('SELECT ahash, phash, dhash FROM images WHERE filename = ?', ('photo.jpg',))
ahash_str, phash_str, dhash_str = cursor.fetchone()

restored_ahash = imagehash.hex_to_hash(ahash_str)
restored_phash = imagehash.hex_to_hash(phash_str)
restored_dhash = imagehash.hex_to_hash(dhash_str)

import json
import imagehash
from PIL import Image

# Create hash data structure
image = Image.open('photo.jpg')
hash_data = {
    'filename': 'photo.jpg',
    'hashes': {
        'average': str(imagehash.average_hash(image)),
        'perceptual': str(imagehash.phash(image)),
        'difference': str(imagehash.dhash(image)),
        'crop_resistant': str(imagehash.crop_resistant_hash(image))
    }
}

# Save to JSON
with open('hashes.json', 'w') as f:
    json.dump(hash_data, f)

# Load and restore hashes
with open('hashes.json', 'r') as f:
    loaded_data = json.load(f)

restored_hashes = {
    'average': imagehash.hex_to_hash(loaded_data['hashes']['average']),
    'perceptual': imagehash.hex_to_hash(loaded_data['hashes']['perceptual']),
    'difference': imagehash.hex_to_hash(loaded_data['hashes']['difference']),
    'crop_resistant': imagehash.hex_to_multihash(loaded_data['hashes']['crop_resistant'])
}

def _binary_array_to_hex(arr):
    """
    Internal function to convert binary array to hexadecimal string.
    
    Args:
        arr (NDArray): Boolean numpy array to convert
    
    Returns:
        str: Hexadecimal string representation
    
    Note:
        This is an internal function not intended for direct use.
        Use str(hash_object) instead for hash-to-string conversion.
    """