subscript.cpp

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/** @file
 *  @author Bram de Greve (bram@cocamware.com)
 *  @author Tom De Muer (tom@cocamware.com)
 *
 *  *** BEGIN LICENSE INFORMATION ***
 *  
 *  The contents of this file are subject to the Common Public Attribution License 
 *  Version 1.0 (the "License"); you may not use this file except in compliance with 
 *  the License. You may obtain a copy of the License at 
 *  http://lass.sourceforge.net/cpal-license. The License is based on the 
 *  Mozilla Public License Version 1.1 but Sections 14 and 15 have been added to cover 
 *  use of software over a computer network and provide for limited attribution for 
 *  the Original Developer. In addition, Exhibit A has been modified to be consistent 
 *  with Exhibit B.
 *  
 *  Software distributed under the License is distributed on an "AS IS" basis, WITHOUT 
 *  WARRANTY OF ANY KIND, either express or implied. See the License for the specific 
 *  language governing rights and limitations under the License.
 *  
 *  The Original Code is LASS - Library of Assembled Shared Sources.
 *  
 *  The Initial Developer of the Original Code is Bram de Greve and Tom De Muer.
 *  The Original Developer is the Initial Developer.
 *  
 *  All portions of the code written by the Initial Developer are:
 *  Copyright (C) 2026 the Initial Developer.
 *  All Rights Reserved.
 *  
 *  Contributor(s):
 *
 *  Alternatively, the contents of this file may be used under the terms of the 
 *  GNU General Public License Version 2 or later (the GPL), in which case the 
 *  provisions of GPL are applicable instead of those above.  If you wish to allow use
 *  of your version of this file only under the terms of the GPL and not to allow 
 *  others to use your version of this file under the CPAL, indicate your decision by 
 *  deleting the provisions above and replace them with the notice and other 
 *  provisions required by the GPL License. If you do not delete the provisions above,
 *  a recipient may use your version of this file under either the CPAL or the GPL.
 *  
 *  *** END LICENSE INFORMATION ***
 */
 
#include "python_common.h"
#include "subscript.h"
#include "python_api.h"
 
namespace lass::python
{
 
Py_ssize_t Slice::adjustIndices(Py_ssize_t sequenceLength)
{
    Py_ssize_t sliceLength = PySlice_AdjustIndices(sequenceLength, &start, &stop, step);
    if (start < 0)
    {
        // This only happens for an empty slice with negative step.
        // Normalize so that start is always a valid iterator index
        // (but not necessarily a valid value index)
        LASS_ASSERT(sliceLength == 0 && step < 0);
        start = 0;
        stop = 0;
    }
    LASS_ASSERT(start >= 0 && start <= sequenceLength);
    LASS_ASSERT(stop >= -1 && stop <= sequenceLength);
    return sliceLength;
}
 
 
 
bool adjustIndexEx(Py_ssize_t *index, Py_ssize_t sequenceLength)
{
    LASS_ASSERT(index);
    LASS_ASSERT(sequenceLength >= 0);
    Py_ssize_t i = *index;
    if (i < 0)
    {
        i += sequenceLength;
    }
    if (i < 0 || i >= sequenceLength)
    {
        LockGIL lock;
        PyErr_SetString(PyExc_IndexError, "index out of range");
        return false;
    }
    *index = i;
    return true;
}
 
 
 
Py_ssize_t adjustIndex(Py_ssize_t index, Py_ssize_t sequenceLength)
{
    if (!adjustIndexEx(&index, sequenceLength))
    {
        impl::fetchAndThrowPythonException(LASS_PRETTY_FUNCTION);
    }
    return index;
}
 
}