import time

import hashlib

def validate_file_performance(filepath, expected_hash, num_iterations=100):

"""

Measures the performance of file content validation against an expected hash.

Args:

filepath (str): The path to the file.

expected_hash (str): The expected SHA-256 hash of the file.

num_iterations (int): The number of validation iterations to perform.

Returns:

tuple: A tuple containing:

- average_time (float): The average time taken per iteration in seconds.

- validation_success (bool): True if all iterations passed validation, False otherwise.

Raises:

FileNotFoundError: If the specified file does not exist.

ValueError: If the expected_hash is not a valid SHA-256 hash.

"""

try:

with open(filepath, "rb") as f:

file_content = f.read()

except FileNotFoundError:

raise FileNotFoundError(f"File not found: {filepath}")

if not isinstance(expected_hash, str) or len(expected_hash) != 64:

raise ValueError("Expected hash must be a 64-character SHA-256 hash.")

try:

calculated_hash = hashlib.sha256(file_content).hexdigest()

except Exception as e:

raise ValueError(f"Error calculating hash: {e}")

if calculated_hash != expected_hash:

print(f"Hash mismatch! Expected: {expected_hash}, Calculated: {calculated_hash}")

return 0.0, False

start_time = time.time()

for _ in range(num_iterations):

calculated_hash = hashlib.sha256(file_content).hexdigest()

if calculated_hash != expected_hash:

print(f"Hash mismatch during iterations! Expected: {expected_hash}, Calculated: {calculated_hash}")

return 0.0, False

end_time = time.time()

total_time = end_time - start_time

average_time = total_time / num_iterations

print(f"Performance validation completed.")

return average_time, True

if __name__ == '__main__':

# Example Usage (replace with your file and expected hash)

filepath = "test_file.txt" #Replace with your file path

expected_hash = "e5b7f39c994b765c9024a8341d544217f8a509d92f8a932a508a777a2460e5b7" # Replace with your expected hash

#Create a test file if it doesn't exist

try:

with open(filepath, "x") as f:

f.write("This is a test file.")

except FileExistsError:

pass

try:

avg_time, success = validate_file_performance(filepath, expected_hash, num_iterations=100)

if success:

print(f"Validation successful. Average time per iteration: {avg_time:.6f} seconds.")

else:

print("Validation failed.")

except (FileNotFoundError, ValueError) as e:

print(f"Error: {e}")