from __future__ import absolute_import, print_function
from ctypes import c_void_p, c_char_p, c_bool, POINTER

from . import ffi
from .common import _encode_string


def address_of_symbol(name):
    """
    Get the in-process address of symbol named *name*.
    An integer is returned, or None if the symbol isn't found.
    """
    return ffi.lib.LLVMPY_SearchAddressOfSymbol(_encode_string(name))


def add_symbol(name, address):
    """
    Register the *address* of global symbol *name*.  This will make
    it usable (e.g. callable) from LLVM-compiled functions.
    """
    ffi.lib.LLVMPY_AddSymbol(_encode_string(name), c_void_p(address))

def load_library_permanently(filename):
    """
    Load an external library
    """
    with ffi.OutputString() as outerr:
        if ffi.lib.LLVMPY_LoadLibraryPermanently(
                _encode_string(filename), outerr):
            raise RuntimeError(str(outerr))

# ============================================================================
# FFI

ffi.lib.LLVMPY_AddSymbol.argtypes = [
    c_char_p,
    c_void_p,
]

ffi.lib.LLVMPY_SearchAddressOfSymbol.argtypes = [c_char_p]
ffi.lib.LLVMPY_SearchAddressOfSymbol.restype = c_void_p

ffi.lib.LLVMPY_LoadLibraryPermanently.argtypes = [c_char_p, POINTER(c_char_p)]
ffi.lib.LLVMPY_LoadLibraryPermanently.restype = c_bool