1dae8e94cce0881f3e10ef5e34b881f512bb52a75Doug Felt/* 2dae8e94cce0881f3e10ef5e34b881f512bb52a75Doug Felt * Copyright (C) 2010 The Android Open Source Project 3dae8e94cce0881f3e10ef5e34b881f512bb52a75Doug Felt * 4dae8e94cce0881f3e10ef5e34b881f512bb52a75Doug Felt * Licensed under the Apache License, Version 2.0 (the "License"); 5dae8e94cce0881f3e10ef5e34b881f512bb52a75Doug Felt * you may not use this file except in compliance with the License. 6dae8e94cce0881f3e10ef5e34b881f512bb52a75Doug Felt * You may obtain a copy of the License at 7dae8e94cce0881f3e10ef5e34b881f512bb52a75Doug Felt * 8dae8e94cce0881f3e10ef5e34b881f512bb52a75Doug Felt * http://www.apache.org/licenses/LICENSE-2.0 9dae8e94cce0881f3e10ef5e34b881f512bb52a75Doug Felt * 10dae8e94cce0881f3e10ef5e34b881f512bb52a75Doug Felt * Unless required by applicable law or agreed to in writing, software 11dae8e94cce0881f3e10ef5e34b881f512bb52a75Doug Felt * distributed under the License is distributed on an "AS IS" BASIS, 12dae8e94cce0881f3e10ef5e34b881f512bb52a75Doug Felt * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13dae8e94cce0881f3e10ef5e34b881f512bb52a75Doug Felt * See the License for the specific language governing permissions and 14dae8e94cce0881f3e10ef5e34b881f512bb52a75Doug Felt * limitations under the License. 15dae8e94cce0881f3e10ef5e34b881f512bb52a75Doug Felt */ 16dae8e94cce0881f3e10ef5e34b881f512bb52a75Doug Felt 17dae8e94cce0881f3e10ef5e34b881f512bb52a75Doug Feltpackage android.text; 18dae8e94cce0881f3e10ef5e34b881f512bb52a75Doug Felt 19e8e45f2c05cb3b6d23f30c8f96d8e0b3699cea7aDoug Feltimport android.text.Layout.Directions; 20e8e45f2c05cb3b6d23f30c8f96d8e0b3699cea7aDoug Felt 21dae8e94cce0881f3e10ef5e34b881f512bb52a75Doug Felt/** 22dae8e94cce0881f3e10ef5e34b881f512bb52a75Doug Felt * Access the ICU bidi implementation. 23dae8e94cce0881f3e10ef5e34b881f512bb52a75Doug Felt * @hide 24dae8e94cce0881f3e10ef5e34b881f512bb52a75Doug Felt */ 25dae8e94cce0881f3e10ef5e34b881f512bb52a75Doug Felt/* package */ class AndroidBidi { 26dae8e94cce0881f3e10ef5e34b881f512bb52a75Doug Felt 27dae8e94cce0881f3e10ef5e34b881f512bb52a75Doug Felt public static int bidi(int dir, char[] chs, byte[] chInfo, int n, boolean haveInfo) { 28dae8e94cce0881f3e10ef5e34b881f512bb52a75Doug Felt if (chs == null || chInfo == null) { 29dae8e94cce0881f3e10ef5e34b881f512bb52a75Doug Felt throw new NullPointerException(); 30dae8e94cce0881f3e10ef5e34b881f512bb52a75Doug Felt } 31dae8e94cce0881f3e10ef5e34b881f512bb52a75Doug Felt 32dae8e94cce0881f3e10ef5e34b881f512bb52a75Doug Felt if (n < 0 || chs.length < n || chInfo.length < n) { 33dae8e94cce0881f3e10ef5e34b881f512bb52a75Doug Felt throw new IndexOutOfBoundsException(); 34dae8e94cce0881f3e10ef5e34b881f512bb52a75Doug Felt } 35dae8e94cce0881f3e10ef5e34b881f512bb52a75Doug Felt 36dae8e94cce0881f3e10ef5e34b881f512bb52a75Doug Felt switch(dir) { 37dae8e94cce0881f3e10ef5e34b881f512bb52a75Doug Felt case Layout.DIR_REQUEST_LTR: dir = 0; break; 38dae8e94cce0881f3e10ef5e34b881f512bb52a75Doug Felt case Layout.DIR_REQUEST_RTL: dir = 1; break; 39dae8e94cce0881f3e10ef5e34b881f512bb52a75Doug Felt case Layout.DIR_REQUEST_DEFAULT_LTR: dir = -2; break; 40dae8e94cce0881f3e10ef5e34b881f512bb52a75Doug Felt case Layout.DIR_REQUEST_DEFAULT_RTL: dir = -1; break; 41dae8e94cce0881f3e10ef5e34b881f512bb52a75Doug Felt default: dir = 0; break; 42dae8e94cce0881f3e10ef5e34b881f512bb52a75Doug Felt } 43dae8e94cce0881f3e10ef5e34b881f512bb52a75Doug Felt 44dae8e94cce0881f3e10ef5e34b881f512bb52a75Doug Felt int result = runBidi(dir, chs, chInfo, n, haveInfo); 45dae8e94cce0881f3e10ef5e34b881f512bb52a75Doug Felt result = (result & 0x1) == 0 ? Layout.DIR_LEFT_TO_RIGHT : Layout.DIR_RIGHT_TO_LEFT; 46dae8e94cce0881f3e10ef5e34b881f512bb52a75Doug Felt return result; 47dae8e94cce0881f3e10ef5e34b881f512bb52a75Doug Felt } 48dae8e94cce0881f3e10ef5e34b881f512bb52a75Doug Felt 49e8e45f2c05cb3b6d23f30c8f96d8e0b3699cea7aDoug Felt /** 50e8e45f2c05cb3b6d23f30c8f96d8e0b3699cea7aDoug Felt * Returns run direction information for a line within a paragraph. 51e8e45f2c05cb3b6d23f30c8f96d8e0b3699cea7aDoug Felt * 52e8e45f2c05cb3b6d23f30c8f96d8e0b3699cea7aDoug Felt * @param dir base line direction, either Layout.DIR_LEFT_TO_RIGHT or 53e8e45f2c05cb3b6d23f30c8f96d8e0b3699cea7aDoug Felt * Layout.DIR_RIGHT_TO_LEFT 54e8e45f2c05cb3b6d23f30c8f96d8e0b3699cea7aDoug Felt * @param levels levels as returned from {@link #bidi} 55e8e45f2c05cb3b6d23f30c8f96d8e0b3699cea7aDoug Felt * @param lstart start of the line in the levels array 56e8e45f2c05cb3b6d23f30c8f96d8e0b3699cea7aDoug Felt * @param chars the character array (used to determine whitespace) 57e8e45f2c05cb3b6d23f30c8f96d8e0b3699cea7aDoug Felt * @param cstart the start of the line in the chars array 58e8e45f2c05cb3b6d23f30c8f96d8e0b3699cea7aDoug Felt * @param len the length of the line 59e8e45f2c05cb3b6d23f30c8f96d8e0b3699cea7aDoug Felt * @return the directions 60e8e45f2c05cb3b6d23f30c8f96d8e0b3699cea7aDoug Felt */ 61e8e45f2c05cb3b6d23f30c8f96d8e0b3699cea7aDoug Felt public static Directions directions(int dir, byte[] levels, int lstart, 62e8e45f2c05cb3b6d23f30c8f96d8e0b3699cea7aDoug Felt char[] chars, int cstart, int len) { 63e8e45f2c05cb3b6d23f30c8f96d8e0b3699cea7aDoug Felt 64e8e45f2c05cb3b6d23f30c8f96d8e0b3699cea7aDoug Felt int baseLevel = dir == Layout.DIR_LEFT_TO_RIGHT ? 0 : 1; 65e8e45f2c05cb3b6d23f30c8f96d8e0b3699cea7aDoug Felt int curLevel = levels[lstart]; 66e8e45f2c05cb3b6d23f30c8f96d8e0b3699cea7aDoug Felt int minLevel = curLevel; 67e8e45f2c05cb3b6d23f30c8f96d8e0b3699cea7aDoug Felt int runCount = 1; 68e8e45f2c05cb3b6d23f30c8f96d8e0b3699cea7aDoug Felt for (int i = lstart + 1, e = lstart + len; i < e; ++i) { 69e8e45f2c05cb3b6d23f30c8f96d8e0b3699cea7aDoug Felt int level = levels[i]; 70e8e45f2c05cb3b6d23f30c8f96d8e0b3699cea7aDoug Felt if (level != curLevel) { 71e8e45f2c05cb3b6d23f30c8f96d8e0b3699cea7aDoug Felt curLevel = level; 72e8e45f2c05cb3b6d23f30c8f96d8e0b3699cea7aDoug Felt ++runCount; 73e8e45f2c05cb3b6d23f30c8f96d8e0b3699cea7aDoug Felt } 74e8e45f2c05cb3b6d23f30c8f96d8e0b3699cea7aDoug Felt } 75e8e45f2c05cb3b6d23f30c8f96d8e0b3699cea7aDoug Felt 76e8e45f2c05cb3b6d23f30c8f96d8e0b3699cea7aDoug Felt // add final run for trailing counter-directional whitespace 77e8e45f2c05cb3b6d23f30c8f96d8e0b3699cea7aDoug Felt int visLen = len; 78e8e45f2c05cb3b6d23f30c8f96d8e0b3699cea7aDoug Felt if ((curLevel & 1) != (baseLevel & 1)) { 79e8e45f2c05cb3b6d23f30c8f96d8e0b3699cea7aDoug Felt // look for visible end 80e8e45f2c05cb3b6d23f30c8f96d8e0b3699cea7aDoug Felt while (--visLen >= 0) { 81e8e45f2c05cb3b6d23f30c8f96d8e0b3699cea7aDoug Felt char ch = chars[cstart + visLen]; 82e8e45f2c05cb3b6d23f30c8f96d8e0b3699cea7aDoug Felt 83e8e45f2c05cb3b6d23f30c8f96d8e0b3699cea7aDoug Felt if (ch == '\n') { 84e8e45f2c05cb3b6d23f30c8f96d8e0b3699cea7aDoug Felt --visLen; 85e8e45f2c05cb3b6d23f30c8f96d8e0b3699cea7aDoug Felt break; 86e8e45f2c05cb3b6d23f30c8f96d8e0b3699cea7aDoug Felt } 87e8e45f2c05cb3b6d23f30c8f96d8e0b3699cea7aDoug Felt 88e8e45f2c05cb3b6d23f30c8f96d8e0b3699cea7aDoug Felt if (ch != ' ' && ch != '\t') { 89e8e45f2c05cb3b6d23f30c8f96d8e0b3699cea7aDoug Felt break; 90e8e45f2c05cb3b6d23f30c8f96d8e0b3699cea7aDoug Felt } 91e8e45f2c05cb3b6d23f30c8f96d8e0b3699cea7aDoug Felt } 92e8e45f2c05cb3b6d23f30c8f96d8e0b3699cea7aDoug Felt ++visLen; 93e8e45f2c05cb3b6d23f30c8f96d8e0b3699cea7aDoug Felt if (visLen != len) { 94e8e45f2c05cb3b6d23f30c8f96d8e0b3699cea7aDoug Felt ++runCount; 95e8e45f2c05cb3b6d23f30c8f96d8e0b3699cea7aDoug Felt } 96e8e45f2c05cb3b6d23f30c8f96d8e0b3699cea7aDoug Felt } 97e8e45f2c05cb3b6d23f30c8f96d8e0b3699cea7aDoug Felt 98e8e45f2c05cb3b6d23f30c8f96d8e0b3699cea7aDoug Felt if (runCount == 1 && minLevel == baseLevel) { 99e8e45f2c05cb3b6d23f30c8f96d8e0b3699cea7aDoug Felt // we're done, only one run on this line 100e8e45f2c05cb3b6d23f30c8f96d8e0b3699cea7aDoug Felt if ((minLevel & 1) != 0) { 101e8e45f2c05cb3b6d23f30c8f96d8e0b3699cea7aDoug Felt return Layout.DIRS_ALL_RIGHT_TO_LEFT; 102e8e45f2c05cb3b6d23f30c8f96d8e0b3699cea7aDoug Felt } 103e8e45f2c05cb3b6d23f30c8f96d8e0b3699cea7aDoug Felt return Layout.DIRS_ALL_LEFT_TO_RIGHT; 104e8e45f2c05cb3b6d23f30c8f96d8e0b3699cea7aDoug Felt } 105e8e45f2c05cb3b6d23f30c8f96d8e0b3699cea7aDoug Felt 106e8e45f2c05cb3b6d23f30c8f96d8e0b3699cea7aDoug Felt int[] ld = new int[runCount * 2]; 107e8e45f2c05cb3b6d23f30c8f96d8e0b3699cea7aDoug Felt int maxLevel = minLevel; 108e8e45f2c05cb3b6d23f30c8f96d8e0b3699cea7aDoug Felt int levelBits = minLevel << Layout.RUN_LEVEL_SHIFT; 109e8e45f2c05cb3b6d23f30c8f96d8e0b3699cea7aDoug Felt { 110e8e45f2c05cb3b6d23f30c8f96d8e0b3699cea7aDoug Felt // Start of first pair is always 0, we write 111e8e45f2c05cb3b6d23f30c8f96d8e0b3699cea7aDoug Felt // length then start at each new run, and the 112e8e45f2c05cb3b6d23f30c8f96d8e0b3699cea7aDoug Felt // last run length after we're done. 113e8e45f2c05cb3b6d23f30c8f96d8e0b3699cea7aDoug Felt int n = 1; 114e8e45f2c05cb3b6d23f30c8f96d8e0b3699cea7aDoug Felt int prev = lstart; 115e8e45f2c05cb3b6d23f30c8f96d8e0b3699cea7aDoug Felt curLevel = minLevel; 116e8e45f2c05cb3b6d23f30c8f96d8e0b3699cea7aDoug Felt for (int i = lstart, e = lstart + visLen; i < e; ++i) { 117e8e45f2c05cb3b6d23f30c8f96d8e0b3699cea7aDoug Felt int level = levels[i]; 118e8e45f2c05cb3b6d23f30c8f96d8e0b3699cea7aDoug Felt if (level != curLevel) { 119e8e45f2c05cb3b6d23f30c8f96d8e0b3699cea7aDoug Felt curLevel = level; 120e8e45f2c05cb3b6d23f30c8f96d8e0b3699cea7aDoug Felt if (level > maxLevel) { 121e8e45f2c05cb3b6d23f30c8f96d8e0b3699cea7aDoug Felt maxLevel = level; 122e8e45f2c05cb3b6d23f30c8f96d8e0b3699cea7aDoug Felt } else if (level < minLevel) { 123e8e45f2c05cb3b6d23f30c8f96d8e0b3699cea7aDoug Felt minLevel = level; 124e8e45f2c05cb3b6d23f30c8f96d8e0b3699cea7aDoug Felt } 125e8e45f2c05cb3b6d23f30c8f96d8e0b3699cea7aDoug Felt // XXX ignore run length limit of 2^RUN_LEVEL_SHIFT 126e8e45f2c05cb3b6d23f30c8f96d8e0b3699cea7aDoug Felt ld[n++] = (i - prev) | levelBits; 127e8e45f2c05cb3b6d23f30c8f96d8e0b3699cea7aDoug Felt ld[n++] = i - lstart; 128e8e45f2c05cb3b6d23f30c8f96d8e0b3699cea7aDoug Felt levelBits = curLevel << Layout.RUN_LEVEL_SHIFT; 129e8e45f2c05cb3b6d23f30c8f96d8e0b3699cea7aDoug Felt prev = i; 130e8e45f2c05cb3b6d23f30c8f96d8e0b3699cea7aDoug Felt } 131e8e45f2c05cb3b6d23f30c8f96d8e0b3699cea7aDoug Felt } 132e8e45f2c05cb3b6d23f30c8f96d8e0b3699cea7aDoug Felt ld[n] = (lstart + visLen - prev) | levelBits; 133e8e45f2c05cb3b6d23f30c8f96d8e0b3699cea7aDoug Felt if (visLen < len) { 134e8e45f2c05cb3b6d23f30c8f96d8e0b3699cea7aDoug Felt ld[++n] = visLen; 135e8e45f2c05cb3b6d23f30c8f96d8e0b3699cea7aDoug Felt ld[++n] = (len - visLen) | (baseLevel << Layout.RUN_LEVEL_SHIFT); 136e8e45f2c05cb3b6d23f30c8f96d8e0b3699cea7aDoug Felt } 137e8e45f2c05cb3b6d23f30c8f96d8e0b3699cea7aDoug Felt } 138e8e45f2c05cb3b6d23f30c8f96d8e0b3699cea7aDoug Felt 139e8e45f2c05cb3b6d23f30c8f96d8e0b3699cea7aDoug Felt // See if we need to swap any runs. 140e8e45f2c05cb3b6d23f30c8f96d8e0b3699cea7aDoug Felt // If the min level run direction doesn't match the base 141e8e45f2c05cb3b6d23f30c8f96d8e0b3699cea7aDoug Felt // direction, we always need to swap (at this point 142e8e45f2c05cb3b6d23f30c8f96d8e0b3699cea7aDoug Felt // we have more than one run). 143e8e45f2c05cb3b6d23f30c8f96d8e0b3699cea7aDoug Felt // Otherwise, we don't need to swap the lowest level. 144e8e45f2c05cb3b6d23f30c8f96d8e0b3699cea7aDoug Felt // Since there are no logically adjacent runs at the same 145e8e45f2c05cb3b6d23f30c8f96d8e0b3699cea7aDoug Felt // level, if the max level is the same as the (new) min 146e8e45f2c05cb3b6d23f30c8f96d8e0b3699cea7aDoug Felt // level, we have a series of alternating levels that 147e8e45f2c05cb3b6d23f30c8f96d8e0b3699cea7aDoug Felt // is already in order, so there's no more to do. 148e8e45f2c05cb3b6d23f30c8f96d8e0b3699cea7aDoug Felt // 149e8e45f2c05cb3b6d23f30c8f96d8e0b3699cea7aDoug Felt boolean swap; 150e8e45f2c05cb3b6d23f30c8f96d8e0b3699cea7aDoug Felt if ((minLevel & 1) == baseLevel) { 151e8e45f2c05cb3b6d23f30c8f96d8e0b3699cea7aDoug Felt minLevel += 1; 152e8e45f2c05cb3b6d23f30c8f96d8e0b3699cea7aDoug Felt swap = maxLevel > minLevel; 153e8e45f2c05cb3b6d23f30c8f96d8e0b3699cea7aDoug Felt } else { 154e8e45f2c05cb3b6d23f30c8f96d8e0b3699cea7aDoug Felt swap = runCount > 1; 155e8e45f2c05cb3b6d23f30c8f96d8e0b3699cea7aDoug Felt } 156e8e45f2c05cb3b6d23f30c8f96d8e0b3699cea7aDoug Felt if (swap) { 157e8e45f2c05cb3b6d23f30c8f96d8e0b3699cea7aDoug Felt for (int level = maxLevel - 1; level >= minLevel; --level) { 158e8e45f2c05cb3b6d23f30c8f96d8e0b3699cea7aDoug Felt for (int i = 0; i < ld.length; i += 2) { 159e8e45f2c05cb3b6d23f30c8f96d8e0b3699cea7aDoug Felt if (levels[ld[i]] >= level) { 160e8e45f2c05cb3b6d23f30c8f96d8e0b3699cea7aDoug Felt int e = i + 2; 161e8e45f2c05cb3b6d23f30c8f96d8e0b3699cea7aDoug Felt while (e < ld.length && levels[ld[e]] >= level) { 162e8e45f2c05cb3b6d23f30c8f96d8e0b3699cea7aDoug Felt e += 2; 163e8e45f2c05cb3b6d23f30c8f96d8e0b3699cea7aDoug Felt } 164e8e45f2c05cb3b6d23f30c8f96d8e0b3699cea7aDoug Felt for (int low = i, hi = e - 2; low < hi; low += 2, hi -= 2) { 165e8e45f2c05cb3b6d23f30c8f96d8e0b3699cea7aDoug Felt int x = ld[low]; ld[low] = ld[hi]; ld[hi] = x; 166e8e45f2c05cb3b6d23f30c8f96d8e0b3699cea7aDoug Felt x = ld[low+1]; ld[low+1] = ld[hi+1]; ld[hi+1] = x; 167e8e45f2c05cb3b6d23f30c8f96d8e0b3699cea7aDoug Felt } 168e8e45f2c05cb3b6d23f30c8f96d8e0b3699cea7aDoug Felt i = e + 2; 169e8e45f2c05cb3b6d23f30c8f96d8e0b3699cea7aDoug Felt } 170e8e45f2c05cb3b6d23f30c8f96d8e0b3699cea7aDoug Felt } 171e8e45f2c05cb3b6d23f30c8f96d8e0b3699cea7aDoug Felt } 172e8e45f2c05cb3b6d23f30c8f96d8e0b3699cea7aDoug Felt } 173e8e45f2c05cb3b6d23f30c8f96d8e0b3699cea7aDoug Felt return new Directions(ld); 174e8e45f2c05cb3b6d23f30c8f96d8e0b3699cea7aDoug Felt } 175e8e45f2c05cb3b6d23f30c8f96d8e0b3699cea7aDoug Felt 176dae8e94cce0881f3e10ef5e34b881f512bb52a75Doug Felt private native static int runBidi(int dir, char[] chs, byte[] chInfo, int n, boolean haveInfo); 177dae8e94cce0881f3e10ef5e34b881f512bb52a75Doug Felt}