156 }
157
158 /**
159 * Increment the counter value.
160 */
161 private static void increment(byte[] b) {
162 int n = b.length - 1;
163 while ((n >= 0) && (++b[n] == 0)) {
164 n--;
165 }
166 }
167
168 /**
169 * Do the actual encryption/decryption operation.
170 * Essentially we XOR the input plaintext/ciphertext stream with a
171 * keystream generated by encrypting the counter values. Counter values
172 * are encrypted on demand.
173 */
174 private int crypt(byte[] in, int inOff, int len, byte[] out, int outOff) {
175
176 cryptBlockCheck(in, inOff, len);
177 cryptBlockCheck(out, outOff, len);
178 return implCrypt(in, inOff, len, out, outOff);
179 }
180
181 // Implementation of crpyt() method. Possibly replaced with a compiler intrinsic.
182 @HotSpotIntrinsicCandidate
183 private int implCrypt(byte[] in, int inOff, int len, byte[] out, int outOff) {
184 int result = len;
185 while (len-- > 0) {
186 if (used >= blockSize) {
187 embeddedCipher.encryptBlock(counter, 0, encryptedCounter, 0);
188 increment(counter);
189 used = 0;
190 }
191 out[outOff++] = (byte)(in[inOff++] ^ encryptedCounter[used++]);
192 }
193 return result;
194 }
195
196 // Used to perform all checks required by the Java semantics
197 // (i.e., null checks and bounds checks) on the input parameters to crypt().
198 // Normally, the Java Runtime performs these checks, however, as crypt() is
199 // possibly replaced with compiler intrinsic, the JDK performs the
200 // required checks instead.
201 // Does not check accesses to class-internal (private) arrays.
202 private static void cryptBlockCheck(byte[] array, int offset, int len) {
203 Objects.requireNonNull(array);
204
205 if (offset < 0 || len < 0 || offset >= array.length) {
206 throw new ArrayIndexOutOfBoundsException(offset);
207 }
208
209 int largestIndex = offset + len - 1;
210 if (largestIndex < 0 || largestIndex >= array.length) {
211 throw new ArrayIndexOutOfBoundsException(largestIndex);
212 }
213 }
214 }
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156 }
157
158 /**
159 * Increment the counter value.
160 */
161 private static void increment(byte[] b) {
162 int n = b.length - 1;
163 while ((n >= 0) && (++b[n] == 0)) {
164 n--;
165 }
166 }
167
168 /**
169 * Do the actual encryption/decryption operation.
170 * Essentially we XOR the input plaintext/ciphertext stream with a
171 * keystream generated by encrypting the counter values. Counter values
172 * are encrypted on demand.
173 */
174 private int crypt(byte[] in, int inOff, int len, byte[] out, int outOff) {
175
176 Objects.checkFromIndexSize(inOff, len, in.length);
177 Objects.checkFromIndexSize(outOff, len, out.length);
178 return implCrypt(in, inOff, len, out, outOff);
179 }
180
181 // Implementation of crpyt() method. Possibly replaced with a compiler intrinsic.
182 @HotSpotIntrinsicCandidate
183 private int implCrypt(byte[] in, int inOff, int len, byte[] out, int outOff) {
184 int result = len;
185 while (len-- > 0) {
186 if (used >= blockSize) {
187 embeddedCipher.encryptBlock(counter, 0, encryptedCounter, 0);
188 increment(counter);
189 used = 0;
190 }
191 out[outOff++] = (byte)(in[inOff++] ^ encryptedCounter[used++]);
192 }
193 return result;
194 }
195
196 }
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