c_utils.py

# Function: Convert some hex value into an array for C programming
import os


def hex_to_c_array(hex_data, var_name):
    c_str = ""

    # Create header guard
    c_str += "#ifndef " + var_name.upper() + "_H\n"
    c_str += "#define " + var_name.upper() + "_H\n\n"

    # Add array length at top of file
    c_str += (
        "\nstatic const unsigned int "
        + var_name
        + "_len = "
        + str(len(hex_data))
        + ";\n"
    )

    # Declare C variable
    c_str += "static const unsigned char " + var_name + "[] = {"
    hex_array = []
    for i, val in enumerate(hex_data):
        # Construct string from hex
        hex_str = format(val, "#04x")

        # Add formatting so each line stays within 80 characters
        if (i + 1) < len(hex_data):
            hex_str += ","
        if (i + 1) % 12 == 0:
            hex_str += "\n "
        hex_array.append(hex_str)

    # Add closing brace
    c_str += "\n " + format(" ".join(hex_array)) + "\n};\n\n"

    # Close out header guard
    c_str += "#endif //" + var_name.upper() + "_H"

    return c_str


def write_model_h(model_name, model, dst_dir="cfiles"):
    # check if dir 'cfiles' exists, if not create it
    if not os.path.exists(dst_dir):
        os.makedirs(dst_dir)
    # Write TFLite model to a C source (or header) file
    with open(f"{dst_dir}/" + model_name + ".h", "w") as file:
        file.write(hex_to_c_array(model, model_name))