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comparison src/org/tmatesoft/hg/core/Nodeid.java @ 261:436bb5f65ce1

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Avoid redundant calls to library when converting a char to hex digit
author Artem Tikhomirov <tikhomirov.artem@gmail.com>
date Wed, 17 Aug 2011 20:30:06 +0200
parents 4b661efb9374
children 3dcd3dd90c77
comparison
equal deleted inserted replaced
260:61cb6724ff36 261:436bb5f65ce1
163 throw new IllegalArgumentException(); 163 throw new IllegalArgumentException();
164 } 164 }
165 // XXX is better impl for String possible? 165 // XXX is better impl for String possible?
166 return fromAscii(asciiRepresentation.getBytes(), 0, 40); 166 return fromAscii(asciiRepresentation.getBytes(), 0, 40);
167 } 167 }
168 168
169 /** 169 /**
170 * Parse encoded representation. Similar to {@link #fromAscii(String)}. 170 * Parse encoded representation. Similar to {@link #fromAscii(String)}.
171 */ 171 */
172 public static Nodeid fromAscii(byte[] asciiRepresentation, int offset, int length) { 172 public static Nodeid fromAscii(byte[] asciiRepresentation, int offset, int length) {
173 if (length != 40) { 173 if (length != 40) {
174 throw new IllegalArgumentException(); 174 throw new IllegalArgumentException();
175 } 175 }
176 byte[] data = new byte[20]; 176 byte[] data = new byte[20];
177 boolean zeroBytes = true; 177 boolean zeroBytes = true;
178 for (int i = 0, j = offset; i < data.length; i++) { 178 for (int i = 0, j = offset; i < data.length; i++) {
179 int hiNibble = Character.digit(asciiRepresentation[j++], 16); 179 int b = asciiRepresentation[j++] & 0xCF; // -0x30 to get decimal digit out from their char, and to uppercase if a letter
180 int lowNibble = Character.digit(asciiRepresentation[j++], 16); 180 int hiNibble = b > 64 ? b - 55 : b;
181 byte b = (byte) (((hiNibble << 4) | lowNibble) & 0xFF); 181 b = asciiRepresentation[j++] & 0xCF;
182 data[i] = b; 182 int lowNibble = b > 64 ? b - 55 : b;
183 if (hiNibble >= 16 || lowNibble >= 16) {
184 throw new IllegalArgumentException(String.format("Characters '%c%c' (%1$d and %2$d) at index %d are not valid hex digits", asciiRepresentation[j-2], asciiRepresentation[j-1], j-2));
185 }
186 data[i] = (byte) (((hiNibble << 4) | lowNibble) & 0xFF);
183 zeroBytes = zeroBytes && b == 0; 187 zeroBytes = zeroBytes && b == 0;
184 } 188 }
185 if (zeroBytes) { 189 if (zeroBytes) {
186 return NULL; 190 return NULL;
187 } 191 }