gecko/js/src/jsarrayinlines.h

/* -*- Mode: C; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*-
 *
 * ***** BEGIN LICENSE BLOCK *****
 * Version: MPL 1.1/GPL 2.0/LGPL 2.1
 *
 * The contents of this file are subject to the Mozilla Public License Version
 * 1.1 (the "License"); you may not use this file except in compliance with
 * the License. You may obtain a copy of the License at
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 *
 * 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 Mozilla Communicator client code, released
 * March 31, 1998.
 *
 * The Initial Developer of the Original Code is
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 * Portions created by the Initial Developer are Copyright (C) 1998
 * the Initial Developer. All Rights Reserved.
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 *
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 * either of the GNU General Public License Version 2 or later (the "GPL"),
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#ifndef jsarrayinlines_h___
#define jsarrayinlines_h___

#include "jsinferinlines.h"

inline void
JSObject::markDenseArrayNotPacked(JSContext *cx)
{
    JS_ASSERT(isDenseArray());
    if (flags & PACKED_ARRAY) {
        flags ^= PACKED_ARRAY;
        MarkTypeObjectFlags(cx, this, js::types::OBJECT_FLAG_NON_PACKED_ARRAY);
    }
}

inline void
JSObject::backfillDenseArrayHoles(JSContext *cx)
{
    /* Ensure an array's elements are fully initialized. */
    ensureDenseArrayInitializedLength(cx, getDenseArrayCapacity(), 0);
}

inline void
JSObject::ensureDenseArrayInitializedLength(JSContext *cx, uint32 index, uint32 extra)
{
    /*
     * Ensure that the array's contents have been initialized up to index, and
     * mark the elements through 'index + extra' as initialized in preparation
     * for a write.
     */
    JS_ASSERT(index + extra <= capacity);
    if (initializedLength < index) {
        markDenseArrayNotPacked(cx);
        js::ClearValueRange(slots + initializedLength, index - initializedLength, true);
    }
    if (initializedLength < index + extra)
        initializedLength = index + extra;
}

inline JSObject::EnsureDenseResult
JSObject::ensureDenseArrayElements(JSContext *cx, uintN index, uintN extra)
{
    JS_ASSERT(isDenseArray());

    uintN currentCapacity = numSlots();

    /*
     * Don't take excessive slow paths when inference is disabled, due to
     * uninitialized slots between initializedLength and capacity.
     */
    JS_ASSERT_IF(!cx->typeInferenceEnabled(), currentCapacity == getDenseArrayInitializedLength());

    uintN requiredCapacity;
    if (extra == 1) {
        /* Optimize for the common case. */
        if (index < currentCapacity) {
            ensureDenseArrayInitializedLength(cx, index, 1);
            return ED_OK;
        }
        requiredCapacity = index + 1;
        if (requiredCapacity == 0) {
            /* Overflow. */
            return ED_SPARSE;
        }
    } else {
        requiredCapacity = index + extra;
        if (requiredCapacity < index) {
            /* Overflow. */
            return ED_SPARSE;
        }
        if (requiredCapacity <= currentCapacity) {
            ensureDenseArrayInitializedLength(cx, index, extra);
            return ED_OK;
        }
    }

    /*
     * We use the extra argument also as a hint about number of non-hole
     * elements to be inserted.
     */
    if (requiredCapacity > MIN_SPARSE_INDEX &&
        willBeSparseDenseArray(requiredCapacity, extra)) {
        return ED_SPARSE;
    }
    if (!growSlots(cx, requiredCapacity))
        return ED_FAILED;

    ensureDenseArrayInitializedLength(cx, index, extra);
    return ED_OK;
}

#endif /* jsarrayinlines_h___ */