This repository has been archived by the owner on Apr 10, 2024. It is now read-only.
/
nsTArray.cpp
279 lines (238 loc) · 8.62 KB
/
nsTArray.cpp
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* vim:set ts=2 sw=2 sts=2 et cindent: */
/* ***** 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
* http://www.mozilla.org/MPL/
*
* 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 C++ array template.
*
* The Initial Developer of the Original Code is Google Inc.
* Portions created by the Initial Developer are Copyright (C) 2005
* the Initial Developer. All Rights Reserved.
*
* Contributor(s):
* Darin Fisher <darin@meer.net>
*
* Alternatively, the contents of this file may be used under the terms of
* either the GNU General Public License Version 2 or later (the "GPL"), or
* the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
* in which case the provisions of the GPL or the LGPL are applicable instead
* of those above. If you wish to allow use of your version of this file only
* under the terms of either the GPL or the LGPL, and not to allow others to
* use your version of this file under the terms of the MPL, indicate your
* decision by deleting the provisions above and replace them with the notice
* and other provisions required by the GPL or the LGPL. If you do not delete
* the provisions above, a recipient may use your version of this file under
* the terms of any one of the MPL, the GPL or the LGPL.
*
* ***** END LICENSE BLOCK ***** */
#include <string.h>
#include "nsTArray.h"
#include "nsXPCOM.h"
#include "nsDebug.h"
nsTArray_base::Header nsTArray_base::sEmptyHdr = { 0, 0, 0 };
nsTArray_base::nsTArray_base()
: mHdr(&sEmptyHdr) {
MOZ_COUNT_CTOR(nsTArray_base);
}
nsTArray_base::~nsTArray_base() {
if (mHdr != &sEmptyHdr && !UsesAutoArrayBuffer()) {
NS_Free(mHdr);
}
MOZ_COUNT_DTOR(nsTArray_base);
}
PRBool
nsTArray_base::EnsureCapacity(size_type capacity, size_type elemSize) {
// This should be the most common case so test this first
if (capacity <= mHdr->mCapacity)
return PR_TRUE;
// If the requested memory allocation exceeds size_type(-1)/2, then our
// doubling algorithm may not be able to allocate it. Additionally we
// couldn't fit in the Header::mCapacity member. Just bail out in cases
// like that. We don't want to be allocating 2 GB+ arrays anyway.
if ((PRUint64)capacity * elemSize > size_type(-1)/2) {
NS_ERROR("Attempting to allocate excessively large array");
return PR_FALSE;
}
if (mHdr == &sEmptyHdr) {
// NS_Alloc new data
Header *header = static_cast<Header*>
(NS_Alloc(sizeof(Header) + capacity * elemSize));
if (!header)
return PR_FALSE;
header->mLength = 0;
header->mCapacity = capacity;
header->mIsAutoArray = 0;
mHdr = header;
return PR_TRUE;
}
// Use doubling algorithm when forced to increase available capacity.
// (Note that mCapacity is only 31 bits wide, so multiplication promotes its
// type. We use |2u| instead of |2| to make sure it's promoted to unsigned.)
capacity = PR_MAX(capacity, mHdr->mCapacity * 2u);
Header *header;
if (UsesAutoArrayBuffer()) {
// NS_Alloc and copy
header = static_cast<Header*>
(NS_Alloc(sizeof(Header) + capacity * elemSize));
if (!header)
return PR_FALSE;
memcpy(header, mHdr, sizeof(Header) + Length() * elemSize);
} else {
// NS_Realloc existing data
size_type size = sizeof(Header) + capacity * elemSize;
header = static_cast<Header*>(NS_Realloc(mHdr, size));
if (!header)
return PR_FALSE;
}
header->mCapacity = capacity;
mHdr = header;
return PR_TRUE;
}
void
nsTArray_base::ShrinkCapacity(size_type elemSize) {
if (mHdr == &sEmptyHdr || UsesAutoArrayBuffer())
return;
if (mHdr->mLength >= mHdr->mCapacity) // should never be greater than...
return;
size_type length = Length();
if (IsAutoArray() && GetAutoArrayBuffer()->mCapacity >= length) {
Header* header = GetAutoArrayBuffer();
// Copy data, but don't copy the header to avoid overwriting mCapacity
header->mLength = length;
memcpy(header + 1, mHdr + 1, length * elemSize);
NS_Free(mHdr);
mHdr = header;
return;
}
if (length == 0) {
NS_ASSERTION(!IsAutoArray(), "autoarray should have fit 0 elements");
NS_Free(mHdr);
mHdr = &sEmptyHdr;
return;
}
size_type size = sizeof(Header) + length * elemSize;
void *ptr = NS_Realloc(mHdr, size);
if (!ptr)
return;
mHdr = static_cast<Header*>(ptr);
mHdr->mCapacity = length;
}
void
nsTArray_base::ShiftData(index_type start, size_type oldLen, size_type newLen,
size_type elemSize) {
if (oldLen == newLen)
return;
// Determine how many elements need to be shifted
size_type num = mHdr->mLength - (start + oldLen);
// Compute the resulting length of the array
mHdr->mLength += newLen - oldLen;
if (mHdr->mLength == 0) {
ShrinkCapacity(elemSize);
} else {
// Maybe nothing needs to be shifted
if (num == 0)
return;
// Perform shift (change units to bytes first)
start *= elemSize;
newLen *= elemSize;
oldLen *= elemSize;
num *= elemSize;
char *base = reinterpret_cast<char*>(mHdr + 1) + start;
memmove(base + newLen, base + oldLen, num);
}
}
PRBool
nsTArray_base::InsertSlotsAt(index_type index, size_type count,
size_type elementSize) {
NS_ASSERTION(index <= Length(), "Bogus insertion index");
size_type newLen = Length() + count;
EnsureCapacity(newLen, elementSize);
// Check for out of memory conditions
if (Capacity() < newLen)
return PR_FALSE;
// Move the existing elements as needed. Note that this will
// change our mLength, so no need to call IncrementLength.
ShiftData(index, 0, count, elementSize);
return PR_TRUE;
}
PRBool
nsTArray_base::SwapArrayElements(nsTArray_base& other, size_type elemSize)
{
#ifdef DEBUG
PRBool isAuto = IsAutoArray();
PRBool otherIsAuto = other.IsAutoArray();
#endif
if (!EnsureNotUsingAutoArrayBuffer(elemSize) ||
!other.EnsureNotUsingAutoArrayBuffer(elemSize)) {
return PR_FALSE;
}
NS_ASSERTION(isAuto == IsAutoArray(), "lost auto info");
NS_ASSERTION(otherIsAuto == other.IsAutoArray(), "lost auto info");
NS_ASSERTION(!UsesAutoArrayBuffer() && !other.UsesAutoArrayBuffer(),
"both should be using an alloced buffer now");
// If the two arrays have different mIsAutoArray values (i.e. one is an
// autoarray and one is not) then simply switching the buffers is going to
// make that bit wrong. We therefore adjust these mIsAutoArray bits before
// switching the buffers so that once the buffers are switched the
// mIsAutoArray bits are right again.
// However, we have to watch out so that we don't set the bit on
// sEmptyHeader. If an array (A) uses the empty header (and the other (B)
// therefore must be an nsAutoTArray) we make A point to the B's autobuffer
// so that when the buffers are switched B points to its own autobuffer.
// Adjust mIsAutoArray flags before swapping the buffers
if (IsAutoArray() && !other.IsAutoArray()) {
if (other.mHdr == &sEmptyHdr) {
// Set other to use our built-in buffer so that we use it
// after the swap below.
other.mHdr = GetAutoArrayBuffer();
other.mHdr->mLength = 0;
}
else {
other.mHdr->mIsAutoArray = 1;
}
mHdr->mIsAutoArray = 0;
}
else if (!IsAutoArray() && other.IsAutoArray()) {
if (mHdr == &sEmptyHdr) {
// Set us to use other's built-in buffer so that other use it
// after the swap below.
mHdr = other.GetAutoArrayBuffer();
mHdr->mLength = 0;
}
else {
mHdr->mIsAutoArray = 1;
}
other.mHdr->mIsAutoArray = 0;
}
// Swap the buffers
Header *h = other.mHdr;
other.mHdr = mHdr;
mHdr = h;
NS_ASSERTION(isAuto == IsAutoArray(), "lost auto info");
NS_ASSERTION(otherIsAuto == other.IsAutoArray(), "lost auto info");
return PR_TRUE;
}
PRBool
nsTArray_base::EnsureNotUsingAutoArrayBuffer(size_type elemSize)
{
if (UsesAutoArrayBuffer()) {
size_type size = sizeof(Header) + Length() * elemSize;
Header* header = static_cast<Header*>(NS_Alloc(size));
if (!header)
return PR_FALSE;
memcpy(header, mHdr, size);
header->mCapacity = Length();
mHdr = header;
}
return PR_TRUE;
}