1 /*
2 * Copyright (c) 2005, 2010, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation. Oracle designates this
8 * particular file as subject to the "Classpath" exception as provided
9 * by Oracle in the LICENSE file that accompanied this code.
10 *
11 * This code is distributed in the hope that it will be useful, but WITHOUT
12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
13 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
14 * version 2 for more details (a copy is included in the LICENSE file that
15 * accompanied this code).
16 *
17 * You should have received a copy of the GNU General Public License version
18 * 2 along with this work; if not, write to the Free Software Foundation,
19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
20 *
21 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
22 * or visit www.oracle.com if you need additional information or have any
23 * questions.
24 */
25
26 package sun.java2d.pipe;
27
28 import sun.misc.Unsafe;
29
30 import javax.tools.annotation.GenerateNativeHeader;
31
32 /**
33 * The RenderBuffer class is a simplified, high-performance, Unsafe wrapper
34 * used for buffering rendering operations in a single-threaded rendering
35 * environment. It's functionality is similar to the ByteBuffer and related
36 * NIO classes. However, the methods in this class perform little to no
37 * alignment or bounds checks for performance reasons. Therefore, it is
38 * the caller's responsibility to ensure that all put() calls are properly
39 * aligned and within bounds:
40 * - int and float values must be aligned on 4-byte boundaries
41 * - long and double values must be aligned on 8-byte boundaries
42 *
43 * This class only includes the bare minimum of methods to support
44 * single-threaded rendering. For example, there is no put(double[]) method
45 * because we currently have no need for such a method in the STR classes.
46 */
47 /* No native methods here, but the constants are needed in the supporting JNI code */
48 @GenerateNativeHeader
49 public class RenderBuffer {
50
51 /**
52 * These constants represent the size of various data types (in bytes).
53 */
54 protected static final long SIZEOF_BYTE = 1L;
55 protected static final long SIZEOF_SHORT = 2L;
56 protected static final long SIZEOF_INT = 4L;
57 protected static final long SIZEOF_FLOAT = 4L;
58 protected static final long SIZEOF_LONG = 8L;
59 protected static final long SIZEOF_DOUBLE = 8L;
60
61 /**
62 * Represents the number of elements at which we have empirically
63 * determined that the average cost of a JNI call exceeds the expense
64 * of an element by element copy. In other words, if the number of
65 * elements in an array to be copied exceeds this value, then we should
66 * use the copyFromArray() method to complete the bulk put operation.
67 * (This value can be adjusted if the cost of JNI downcalls is reduced
68 * in a future release.)
69 */
70 private static final int COPY_FROM_ARRAY_THRESHOLD = 6;
71
72 protected final Unsafe unsafe;
73 protected final long baseAddress;
74 protected final long endAddress;
75 protected long curAddress;
76 protected final int capacity;
77
78 protected RenderBuffer(int numBytes) {
79 unsafe = Unsafe.getUnsafe();
80 curAddress = baseAddress = unsafe.allocateMemory(numBytes);
81 endAddress = baseAddress + numBytes;
82 capacity = numBytes;
83 }
84
85 /**
86 * Allocates a fresh buffer using the machine endianness.
87 */
88 public static RenderBuffer allocate(int numBytes) {
89 return new RenderBuffer(numBytes);
90 }
91
92 /**
93 * Returns the base address of the underlying memory buffer.
94 */
95 public final long getAddress() {
96 return baseAddress;
97 }
98
99 /**
100 * The behavior (and names) of the following methods are nearly
101 * identical to their counterparts in the various NIO Buffer classes.
102 */
103
104 public final int capacity() {
105 return capacity;
106 }
107
108 public final int remaining() {
109 return (int)(endAddress - curAddress);
110 }
111
112 public final int position() {
113 return (int)(curAddress - baseAddress);
114 }
115
116 public final void position(long numBytes) {
117 curAddress = baseAddress + numBytes;
118 }
119
120 public final void clear() {
121 curAddress = baseAddress;
122 }
123
124 public final RenderBuffer skip(long numBytes) {
125 curAddress += numBytes;
126 return this;
127 }
128
129 /**
130 * putByte() methods...
131 */
132
133 public final RenderBuffer putByte(byte x) {
134 unsafe.putByte(curAddress, x);
135 curAddress += SIZEOF_BYTE;
136 return this;
137 }
138
139 public RenderBuffer put(byte[] x) {
140 return put(x, 0, x.length);
141 }
142
143 public RenderBuffer put(byte[] x, int offset, int length) {
144 if (length > COPY_FROM_ARRAY_THRESHOLD) {
145 long offsetInBytes = offset * SIZEOF_BYTE + Unsafe.ARRAY_BYTE_BASE_OFFSET;
146 long lengthInBytes = length * SIZEOF_BYTE;
147 unsafe.copyMemory(x, offsetInBytes, null, curAddress, lengthInBytes);
148 position(position() + lengthInBytes);
149 } else {
150 int end = offset + length;
151 for (int i = offset; i < end; i++) {
152 putByte(x[i]);
153 }
154 }
155 return this;
156 }
157
158 /**
159 * putShort() methods...
160 */
161
162 public final RenderBuffer putShort(short x) {
163 // assert (position() % SIZEOF_SHORT == 0);
164 unsafe.putShort(curAddress, x);
165 curAddress += SIZEOF_SHORT;
166 return this;
167 }
168
169 public RenderBuffer put(short[] x) {
170 return put(x, 0, x.length);
171 }
172
173 public RenderBuffer put(short[] x, int offset, int length) {
174 // assert (position() % SIZEOF_SHORT == 0);
175 if (length > COPY_FROM_ARRAY_THRESHOLD) {
176 long offsetInBytes = offset * SIZEOF_SHORT + Unsafe.ARRAY_SHORT_BASE_OFFSET;
177 long lengthInBytes = length * SIZEOF_SHORT;
178 unsafe.copyMemory(x, offsetInBytes, null, curAddress, lengthInBytes);
179 position(position() + lengthInBytes);
180 } else {
181 int end = offset + length;
182 for (int i = offset; i < end; i++) {
183 putShort(x[i]);
184 }
185 }
186 return this;
187 }
188
189 /**
190 * putInt() methods...
191 */
192
193 public final RenderBuffer putInt(int pos, int x) {
194 // assert (baseAddress + pos % SIZEOF_INT == 0);
195 unsafe.putInt(baseAddress + pos, x);
196 return this;
197 }
198
199 public final RenderBuffer putInt(int x) {
200 // assert (position() % SIZEOF_INT == 0);
201 unsafe.putInt(curAddress, x);
202 curAddress += SIZEOF_INT;
203 return this;
204 }
205
206 public RenderBuffer put(int[] x) {
207 return put(x, 0, x.length);
208 }
209
210 public RenderBuffer put(int[] x, int offset, int length) {
211 // assert (position() % SIZEOF_INT == 0);
212 if (length > COPY_FROM_ARRAY_THRESHOLD) {
213 long offsetInBytes = offset * SIZEOF_INT + Unsafe.ARRAY_INT_BASE_OFFSET;
214 long lengthInBytes = length * SIZEOF_INT;
215 unsafe.copyMemory(x, offsetInBytes, null, curAddress, lengthInBytes);
216 position(position() + lengthInBytes);
217 } else {
218 int end = offset + length;
219 for (int i = offset; i < end; i++) {
220 putInt(x[i]);
221 }
222 }
223 return this;
224 }
225
226 /**
227 * putFloat() methods...
228 */
229
230 public final RenderBuffer putFloat(float x) {
231 // assert (position() % SIZEOF_FLOAT == 0);
232 unsafe.putFloat(curAddress, x);
233 curAddress += SIZEOF_FLOAT;
234 return this;
235 }
236
237 public RenderBuffer put(float[] x) {
238 return put(x, 0, x.length);
239 }
240
241 public RenderBuffer put(float[] x, int offset, int length) {
242 // assert (position() % SIZEOF_FLOAT == 0);
243 if (length > COPY_FROM_ARRAY_THRESHOLD) {
244 long offsetInBytes = offset * SIZEOF_FLOAT + Unsafe.ARRAY_FLOAT_BASE_OFFSET;
245 long lengthInBytes = length * SIZEOF_FLOAT;
246 unsafe.copyMemory(x, offsetInBytes, null, curAddress, lengthInBytes);
247 position(position() + lengthInBytes);
248 } else {
249 int end = offset + length;
250 for (int i = offset; i < end; i++) {
251 putFloat(x[i]);
252 }
253 }
254 return this;
255 }
256
257 /**
258 * putLong() methods...
259 */
260
261 public final RenderBuffer putLong(long x) {
262 // assert (position() % SIZEOF_LONG == 0);
263 unsafe.putLong(curAddress, x);
264 curAddress += SIZEOF_LONG;
265 return this;
266 }
267
268 public RenderBuffer put(long[] x) {
269 return put(x, 0, x.length);
270 }
271
272 public RenderBuffer put(long[] x, int offset, int length) {
273 // assert (position() % SIZEOF_LONG == 0);
274 if (length > COPY_FROM_ARRAY_THRESHOLD) {
275 long offsetInBytes = offset * SIZEOF_LONG + Unsafe.ARRAY_LONG_BASE_OFFSET;
276 long lengthInBytes = length * SIZEOF_LONG;
277 unsafe.copyMemory(x, offsetInBytes, null, curAddress, lengthInBytes);
278 position(position() + lengthInBytes);
279 } else {
280 int end = offset + length;
281 for (int i = offset; i < end; i++) {
282 putLong(x[i]);
283 }
284 }
285 return this;
286 }
287
288 /**
289 * putDouble() method(s)...
290 */
291
292 public final RenderBuffer putDouble(double x) {
293 // assert (position() % SIZEOF_DOUBLE == 0);
294 unsafe.putDouble(curAddress, x);
295 curAddress += SIZEOF_DOUBLE;
296 return this;
297 }
298 }