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src/java.desktop/share/classes/sun/font/BidiUtils.java

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  31  * under terms of a License Agreement between IBM and Sun.
  32  * This technology is protected by multiple US and International
  33  * patents. This notice and attribution to IBM may not be removed.
  34  */
  35 
  36 package sun.font;
  37 
  38 import java.text.Bidi;
  39 
  40 public final class BidiUtils {
  41 
  42 
  43 
  44     /**
  45      * Return the level of each character into the levels array starting at start.
  46      * This is a convenience method for clients who prefer to use an explicit levels
  47      * array instead of iterating over the runs.
  48      *
  49      * @param levels the array to receive the character levels
  50      * @param start the starting offset into the array
  51      * @throws IndexOutOfBoundsException if <code>start</code> is less than 0 or
  52      * <code>start + getLength()</code> is greater than <code>levels.length</code>.
  53      */
  54     public static void getLevels(Bidi bidi, byte[] levels, int start) {
  55         int limit = start + bidi.getLength();
  56 
  57         if (start < 0 || limit > levels.length) {
  58             throw new IndexOutOfBoundsException("levels.length = " + levels.length +
  59                 " start: " + start + " limit: " + limit);
  60         }
  61 
  62         int runCount = bidi.getRunCount();
  63         int p = start;
  64         for (int i = 0; i < runCount; ++i) {
  65             int rlimit = start + bidi.getRunLimit(i);
  66             byte rlevel = (byte)bidi.getRunLevel(i);
  67 
  68             while (p < rlimit) {
  69                 levels[p++] = rlevel;
  70             }
  71         }
  72     }
  73 
  74     /**
  75      * Return an array containing the resolved bidi level of each character, in logical order.
  76      * @return an array containing the level of each character, in logical order.
  77      */
  78     public static byte[] getLevels(Bidi bidi) {
  79         byte[] levels = new byte[bidi.getLength()];
  80         getLevels(bidi, levels, 0);
  81         return levels;
  82     }
  83 
  84     static final char NUMLEVELS = 62;
  85 
  86     /**
  87      * Given level data, compute a a visual to logical mapping.
  88      * The leftmost (or topmost) character is at visual index zero.  The
  89      * logical index of the character is derived from the visual index
  90      * by the expression <code>li = map[vi];</code>.
  91      * @param levels the levels array
  92      * @return the mapping array from visual to logical
  93      */
  94     public static int[] createVisualToLogicalMap(byte[] levels) {
  95         int len = levels.length;
  96         int[] mapping = new int[len];
  97 
  98         byte lowestOddLevel = (byte)(NUMLEVELS + 1);
  99         byte highestLevel = 0;
 100 
 101         // initialize mapping and levels
 102 
 103         for (int i = 0; i < len; i++) {
 104             mapping[i] = i;
 105 
 106             byte level = levels[i];
 107             if (level > highestLevel) {
 108                 highestLevel = level;
 109             }
 110 


 131                 int end = i - 1;
 132 
 133                 while (begin < end) {
 134                     int temp = mapping[begin];
 135                     mapping[begin] = mapping[end];
 136                     mapping[end] = temp;
 137                     ++begin;
 138                     --end;
 139                 }
 140             }
 141 
 142             --highestLevel;
 143         }
 144 
 145         return mapping;
 146     }
 147 
 148     /**
 149      * Return the inverse position map.  The source array must map one-to-one (each value
 150      * is distinct and the values run from zero to the length of the array minus one).
 151      * For example, if <code>values[i] = j</code>, then <code>inverse[j] = i</code>.
 152      * @param values the source ordering array
 153      * @return the inverse array
 154      */
 155     public static int[] createInverseMap(int[] values) {
 156         if (values == null) {
 157             return null;
 158         }
 159 
 160         int[] result = new int[values.length];
 161         for (int i = 0; i < values.length; i++) {
 162             result[values[i]] = i;
 163         }
 164 
 165         return result;
 166     }
 167 
 168 
 169     /**
 170      * Return an array containing contiguous values from 0 to length
 171      * having the same ordering as the source array. If this would be




  31  * under terms of a License Agreement between IBM and Sun.
  32  * This technology is protected by multiple US and International
  33  * patents. This notice and attribution to IBM may not be removed.
  34  */
  35 
  36 package sun.font;
  37 
  38 import java.text.Bidi;
  39 
  40 public final class BidiUtils {
  41 
  42 
  43 
  44     /**
  45      * Return the level of each character into the levels array starting at start.
  46      * This is a convenience method for clients who prefer to use an explicit levels
  47      * array instead of iterating over the runs.
  48      *
  49      * @param levels the array to receive the character levels
  50      * @param start the starting offset into the array
  51      * @throws IndexOutOfBoundsException if {@code start} is less than 0 or
  52      * {@code start + getLength()} is greater than {@code levels.length}.
  53      */
  54     public static void getLevels(Bidi bidi, byte[] levels, int start) {
  55         int limit = start + bidi.getLength();
  56 
  57         if (start < 0 || limit > levels.length) {
  58             throw new IndexOutOfBoundsException("levels.length = " + levels.length +
  59                 " start: " + start + " limit: " + limit);
  60         }
  61 
  62         int runCount = bidi.getRunCount();
  63         int p = start;
  64         for (int i = 0; i < runCount; ++i) {
  65             int rlimit = start + bidi.getRunLimit(i);
  66             byte rlevel = (byte)bidi.getRunLevel(i);
  67 
  68             while (p < rlimit) {
  69                 levels[p++] = rlevel;
  70             }
  71         }
  72     }
  73 
  74     /**
  75      * Return an array containing the resolved bidi level of each character, in logical order.
  76      * @return an array containing the level of each character, in logical order.
  77      */
  78     public static byte[] getLevels(Bidi bidi) {
  79         byte[] levels = new byte[bidi.getLength()];
  80         getLevels(bidi, levels, 0);
  81         return levels;
  82     }
  83 
  84     static final char NUMLEVELS = 62;
  85 
  86     /**
  87      * Given level data, compute a a visual to logical mapping.
  88      * The leftmost (or topmost) character is at visual index zero.  The
  89      * logical index of the character is derived from the visual index
  90      * by the expression {@code li = map[vi];}.
  91      * @param levels the levels array
  92      * @return the mapping array from visual to logical
  93      */
  94     public static int[] createVisualToLogicalMap(byte[] levels) {
  95         int len = levels.length;
  96         int[] mapping = new int[len];
  97 
  98         byte lowestOddLevel = (byte)(NUMLEVELS + 1);
  99         byte highestLevel = 0;
 100 
 101         // initialize mapping and levels
 102 
 103         for (int i = 0; i < len; i++) {
 104             mapping[i] = i;
 105 
 106             byte level = levels[i];
 107             if (level > highestLevel) {
 108                 highestLevel = level;
 109             }
 110 


 131                 int end = i - 1;
 132 
 133                 while (begin < end) {
 134                     int temp = mapping[begin];
 135                     mapping[begin] = mapping[end];
 136                     mapping[end] = temp;
 137                     ++begin;
 138                     --end;
 139                 }
 140             }
 141 
 142             --highestLevel;
 143         }
 144 
 145         return mapping;
 146     }
 147 
 148     /**
 149      * Return the inverse position map.  The source array must map one-to-one (each value
 150      * is distinct and the values run from zero to the length of the array minus one).
 151      * For example, if {@code values[i] = j}, then {@code inverse[j] = i}.
 152      * @param values the source ordering array
 153      * @return the inverse array
 154      */
 155     public static int[] createInverseMap(int[] values) {
 156         if (values == null) {
 157             return null;
 158         }
 159 
 160         int[] result = new int[values.length];
 161         for (int i = 0; i < values.length; i++) {
 162             result[values[i]] = i;
 163         }
 164 
 165         return result;
 166     }
 167 
 168 
 169     /**
 170      * Return an array containing contiguous values from 0 to length
 171      * having the same ordering as the source array. If this would be


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