#
# Copyright (c) 2008-10, Mahadevan R All rights reserved.
#
# Redistribution and use in source and binary forms, with or without
# modification, are permitted provided that the following conditions are met:
#
#  * Redistributions of source code must retain the above copyright notice,
#    this list of conditions and the following disclaimer.
#
#  * Redistributions in binary form must reproduce the above copyright notice,
#    this list of conditions and the following disclaimer in the documentation
#    and/or other materials provided with the distribution.
#
#  * Neither the name of this software, nor the names of its
#    contributors may be used to endorse or promote products derived from
#    this software without specific prior written permission.
#
# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
# A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
# OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
# LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
#

"""Utility functions and classes.

Used only in other modules, not for public use."""

import llvm
import llvm._core as _core  # for PyCObjectVoidPtrToPyLong


#===----------------------------------------------------------------------===
# A set of helpers to check various things. Raises exceptions on
# failures.
#===----------------------------------------------------------------------===

def check_gen(obj, typ):
    if not isinstance(obj, typ):
        typ_str = typ.__name__
        msg = "argument not an instance of llvm.core.%s" % typ_str
        raise TypeError(msg)

def check_is_unowned(ownable):
    if ownable.owner:
        raise llvm.LLVMException("object is already owned")


#===----------------------------------------------------------------------===
# A set of helpers to unpack a list of Python wrapper objects
# into a list of PyCObject wrapped objects, checking types along
# the way.
#===----------------------------------------------------------------------===

def unpack_gen(objlist, check_fn):
    for obj in objlist: check_fn(obj)
    return [ obj.ptr for obj in objlist ]

def unpack_gen_allow_none(objlist, check_fn):
    for obj in objlist:
        if obj is not None:
            check_fn(obj)
    return [ (obj.ptr if obj is not None else None) for obj in objlist ]

#===----------------------------------------------------------------------===
# Helper to wrap over iterables (LLVMFirstXXX, LLVMNextXXX). This used
# to be a generator, but that loses subscriptability of the result, so
# we now return a list.
#===----------------------------------------------------------------------===

def wrapiter(first, next, container, wrapper):
    ret = []
    ptr = first(container)
    while ptr:
        ret.append(wrapper(ptr))
        ptr = next(ptr)
    return ret


#===----------------------------------------------------------------------===
# Py2/3 compatibility string check
#===----------------------------------------------------------------------===
def _isstring_py2(x):
    return isinstance(x, basestring)

def _isstring_py3(x):
    return isinstance(x, str)

def _isstring_choose():
    try:
        basestring
        return _isstring_py2
    except:
        return _isstring_py3

isstring = _isstring_choose()

try:
    unicode_type = unicode
except NameError:  # Py3
    unicode_type = str