Objectivo
Desarrollar un programa Python que verifique si un archivo de imagen BMP es válido comprobando su encabezado.
El programa debe leer el archivo y confirmar que los dos primeros bytes coinciden con "B" y "M" (códigos ASCII 0x42 y 0x4D). Si es así, indica que el archivo es potencialmente una imagen BMP válida.
Ejemplo Ejercicio Python
Mostrar Código Python
def verify_bmp_header(file_name):
"""
Verifies if the given file is a valid BMP image by checking its header.
Parameters:
file_name (str): The name of the file to check.
Returns:
bool: True if the file is a valid BMP, False otherwise.
"""
try:
with open(file_name, 'rb') as file:
# Read the first two bytes of the file
header = file.read(2)
# Check if the first two bytes match 'B' and 'M' (0x42 and 0x4D)
if header == b'BM':
return True
else:
return False
except FileNotFoundError:
print(f"The file '{file_name}' was not found.")
return False
except Exception as e:
print(f"An error occurred: {e}")
return False
# Main program execution
if __name__ == "__main__":
# Ask the user to input the file name
file_name = input("Please enter the BMP file name to verify: ")
# Verify if the file is a valid BMP image
if verify_bmp_header(file_name):
print(f"The file '{file_name}' is a valid BMP image.")
else:
print(f"The file '{file_name}' is not a valid BMP image.")
Output
Assume you have a BMP file named image.bmp. When you run the program, it will behave as follows:
Please enter the BMP file name to verify: image.bmp
The file 'image.bmp' is a valid BMP image.
If the file is not a BMP or the header does not match "BM", the program will output:
Please enter the BMP file name to verify: image.jpg
The file 'image.jpg' is not a valid BMP image.
If the file does not exist, it will output:
Please enter the BMP file name to verify: nonexistent.bmp
The file 'nonexistent.bmp' was not found.
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