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289 lines
8.9 KiB
C++
289 lines
8.9 KiB
C++
/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
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/* vim:set ts=2 sw=2 sts=2 et cindent: */
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/* ***** BEGIN LICENSE BLOCK *****
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* Version: MPL 1.1/GPL 2.0/LGPL 2.1
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*
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* The contents of this file are subject to the Mozilla Public License Version
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* 1.1 (the "License"); you may not use this file except in compliance with
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* the License. You may obtain a copy of the License at
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* http://www.mozilla.org/MPL/
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*
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* Software distributed under the License is distributed on an "AS IS" basis,
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* WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
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* for the specific language governing rights and limitations under the
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* License.
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*
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* The Original Code is C++ array template.
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*
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* The Initial Developer of the Original Code is Google Inc.
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* Portions created by the Initial Developer are Copyright (C) 2005
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* the Initial Developer. All Rights Reserved.
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*
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* Contributor(s):
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* Darin Fisher <darin@meer.net>
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*
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* Alternatively, the contents of this file may be used under the terms of
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* either the GNU General Public License Version 2 or later (the "GPL"), or
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* the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
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* in which case the provisions of the GPL or the LGPL are applicable instead
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* of those above. If you wish to allow use of your version of this file only
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* under the terms of either the GPL or the LGPL, and not to allow others to
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* use your version of this file under the terms of the MPL, indicate your
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* decision by deleting the provisions above and replace them with the notice
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* and other provisions required by the GPL or the LGPL. If you do not delete
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* the provisions above, a recipient may use your version of this file under
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* the terms of any one of the MPL, the GPL or the LGPL.
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*
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* ***** END LICENSE BLOCK ***** */
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#ifndef nsTArray_h__
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# error "Don't include this file directly"
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#endif
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template<class Alloc>
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nsTArray_base<Alloc>::nsTArray_base()
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: mHdr(EmptyHdr()) {
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MOZ_COUNT_CTOR(nsTArray_base);
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}
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template<class Alloc>
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nsTArray_base<Alloc>::~nsTArray_base() {
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if (mHdr != EmptyHdr() && !UsesAutoArrayBuffer()) {
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Alloc::Free(mHdr);
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}
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MOZ_COUNT_DTOR(nsTArray_base);
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}
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template<class Alloc>
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PRBool
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nsTArray_base<Alloc>::EnsureCapacity(size_type capacity, size_type elemSize) {
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// This should be the most common case so test this first
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if (capacity <= mHdr->mCapacity)
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return PR_TRUE;
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// If the requested memory allocation exceeds size_type(-1)/2, then
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// our doubling algorithm may not be able to allocate it.
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// Additionally we couldn't fit in the Header::mCapacity
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// member. Just bail out in cases like that. We don't want to be
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// allocating 2 GB+ arrays anyway.
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if ((PRUint64)capacity * elemSize > size_type(-1)/2) {
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NS_ERROR("Attempting to allocate excessively large array");
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return PR_FALSE;
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}
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if (mHdr == EmptyHdr()) {
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// Malloc() new data
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Header *header = static_cast<Header*>
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(Alloc::Malloc(sizeof(Header) + capacity * elemSize));
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if (!header)
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return PR_FALSE;
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header->mLength = 0;
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header->mCapacity = capacity;
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header->mIsAutoArray = 0;
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mHdr = header;
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return PR_TRUE;
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}
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// Use doubling algorithm when forced to increase available
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// capacity. (Note that mCapacity is only 31 bits wide, so
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// multiplication promotes its type. We use |2u| instead of |2|
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// to make sure it's promoted to unsigned.)
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capacity = NS_MAX<size_type>(capacity, mHdr->mCapacity * 2U);
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Header *header;
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if (UsesAutoArrayBuffer()) {
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// Malloc() and copy
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header = static_cast<Header*>
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(Alloc::Malloc(sizeof(Header) + capacity * elemSize));
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if (!header)
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return PR_FALSE;
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memcpy(header, mHdr, sizeof(Header) + Length() * elemSize);
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} else {
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// Realloc() existing data
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size_type size = sizeof(Header) + capacity * elemSize;
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header = static_cast<Header*>(Alloc::Realloc(mHdr, size));
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if (!header)
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return PR_FALSE;
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}
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header->mCapacity = capacity;
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mHdr = header;
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return PR_TRUE;
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}
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template<class Alloc>
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void
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nsTArray_base<Alloc>::ShrinkCapacity(size_type elemSize) {
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if (mHdr == EmptyHdr() || UsesAutoArrayBuffer())
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return;
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if (mHdr->mLength >= mHdr->mCapacity) // should never be greater than...
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return;
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size_type length = Length();
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if (IsAutoArray() && GetAutoArrayBuffer()->mCapacity >= length) {
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Header* header = GetAutoArrayBuffer();
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// Copy data, but don't copy the header to avoid overwriting mCapacity
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header->mLength = length;
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memcpy(header + 1, mHdr + 1, length * elemSize);
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Alloc::Free(mHdr);
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mHdr = header;
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return;
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}
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if (length == 0) {
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NS_ASSERTION(!IsAutoArray(), "autoarray should have fit 0 elements");
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Alloc::Free(mHdr);
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mHdr = EmptyHdr();
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return;
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}
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size_type size = sizeof(Header) + length * elemSize;
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void *ptr = Alloc::Realloc(mHdr, size);
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if (!ptr)
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return;
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mHdr = static_cast<Header*>(ptr);
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mHdr->mCapacity = length;
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}
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template<class Alloc>
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void
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nsTArray_base<Alloc>::ShiftData(index_type start,
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size_type oldLen, size_type newLen,
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size_type elemSize) {
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if (oldLen == newLen)
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return;
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// Determine how many elements need to be shifted
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size_type num = mHdr->mLength - (start + oldLen);
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// Compute the resulting length of the array
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mHdr->mLength += newLen - oldLen;
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if (mHdr->mLength == 0) {
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ShrinkCapacity(elemSize);
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} else {
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// Maybe nothing needs to be shifted
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if (num == 0)
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return;
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// Perform shift (change units to bytes first)
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start *= elemSize;
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newLen *= elemSize;
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oldLen *= elemSize;
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num *= elemSize;
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char *base = reinterpret_cast<char*>(mHdr + 1) + start;
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memmove(base + newLen, base + oldLen, num);
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}
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}
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template<class Alloc>
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PRBool
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nsTArray_base<Alloc>::InsertSlotsAt(index_type index, size_type count,
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size_type elementSize) {
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NS_ASSERTION(index <= Length(), "Bogus insertion index");
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size_type newLen = Length() + count;
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EnsureCapacity(newLen, elementSize);
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// Check for out of memory conditions
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if (Capacity() < newLen)
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return PR_FALSE;
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// Move the existing elements as needed. Note that this will
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// change our mLength, so no need to call IncrementLength.
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ShiftData(index, 0, count, elementSize);
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return PR_TRUE;
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}
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template<class Alloc>
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template<class Allocator>
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PRBool
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nsTArray_base<Alloc>::SwapArrayElements(nsTArray_base<Allocator>& other,
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size_type elemSize) {
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#ifdef DEBUG
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PRBool isAuto = IsAutoArray();
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PRBool otherIsAuto = other.IsAutoArray();
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#endif
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if (!EnsureNotUsingAutoArrayBuffer(elemSize) ||
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!other.EnsureNotUsingAutoArrayBuffer(elemSize)) {
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return PR_FALSE;
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}
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NS_ASSERTION(isAuto == IsAutoArray(), "lost auto info");
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NS_ASSERTION(otherIsAuto == other.IsAutoArray(), "lost auto info");
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NS_ASSERTION(!UsesAutoArrayBuffer() && !other.UsesAutoArrayBuffer(),
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"both should be using an alloced buffer now");
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// If the two arrays have different mIsAutoArray values (i.e. one is
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// an autoarray and one is not) then simply switching the buffers is
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// going to make that bit wrong. We therefore adjust these
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// mIsAutoArray bits before switching the buffers so that once the
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// buffers are switched the mIsAutoArray bits are right again.
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// However, we have to watch out so that we don't set the bit on
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// sEmptyHeader. If an array (A) uses the empty header (and the
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// other (B) therefore must be an nsAutoTArray) we make A point to
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// the B's autobuffer so that when the buffers are switched B points
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// to its own autobuffer.
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// Adjust mIsAutoArray flags before swapping the buffers
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if (IsAutoArray() && !other.IsAutoArray()) {
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if (other.mHdr == EmptyHdr()) {
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// Set other to use our built-in buffer so that we use it
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// after the swap below.
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other.mHdr = GetAutoArrayBuffer();
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other.mHdr->mLength = 0;
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}
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else {
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other.mHdr->mIsAutoArray = 1;
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}
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mHdr->mIsAutoArray = 0;
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}
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else if (!IsAutoArray() && other.IsAutoArray()) {
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if (mHdr == EmptyHdr()) {
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// Set us to use other's built-in buffer so that other use it
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// after the swap below.
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mHdr = other.GetAutoArrayBuffer();
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mHdr->mLength = 0;
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}
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else {
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mHdr->mIsAutoArray = 1;
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}
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other.mHdr->mIsAutoArray = 0;
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}
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// Swap the buffers
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Header *h = other.mHdr;
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other.mHdr = mHdr;
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mHdr = h;
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NS_ASSERTION(isAuto == IsAutoArray(), "lost auto info");
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NS_ASSERTION(otherIsAuto == other.IsAutoArray(), "lost auto info");
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return PR_TRUE;
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}
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template<class Alloc>
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PRBool
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nsTArray_base<Alloc>::EnsureNotUsingAutoArrayBuffer(size_type elemSize) {
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if (UsesAutoArrayBuffer()) {
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size_type size = sizeof(Header) + Length() * elemSize;
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Header* header = static_cast<Header*>(Alloc::Malloc(size));
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if (!header)
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return PR_FALSE;
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memcpy(header, mHdr, size);
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header->mCapacity = Length();
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mHdr = header;
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}
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return PR_TRUE;
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}
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