1 /*
   2  * Permission is hereby granted, free of charge, to any person obtaining a copy of
   3  * this software and associated documentation files (the "Software"), to deal in
   4  * the Software without restriction, including without limitation the rights to
   5  * use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies
   6  * of the Software, and to permit persons to whom the Software is furnished to do
   7  * so, subject to the following conditions:
   8  *
   9  * The above copyright notice and this permission notice shall be included in all
  10  * copies or substantial portions of the Software.
  11  *
  12  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  13  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  14  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
  15  * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  16  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
  17  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
  18  * SOFTWARE.
  19  */
  20 package jdk.nashorn.internal.runtime.regexp.joni;
  21 
  22 final class MinMaxLen {
  23     int min; /* min byte length */
  24     int max; /* max byte length */
  25 
  26     MinMaxLen() {
  27     }
  28 
  29     MinMaxLen(final int min, final int max) {
  30         this.min = min;
  31         this.max = max;
  32     }
  33 
  34     /* 1000 / (min-max-dist + 1) */
  35     private static final short distValues[] = {
  36         1000,  500,  333,  250,  200,  167,  143,  125,  111,  100,
  37           91,   83,   77,   71,   67,   63,   59,   56,   53,   50,
  38           48,   45,   43,   42,   40,   38,   37,   36,   34,   33,
  39           32,   31,   30,   29,   29,   28,   27,   26,   26,   25,
  40           24,   24,   23,   23,   22,   22,   21,   21,   20,   20,
  41           20,   19,   19,   19,   18,   18,   18,   17,   17,   17,
  42           16,   16,   16,   16,   15,   15,   15,   15,   14,   14,
  43           14,   14,   14,   14,   13,   13,   13,   13,   13,   13,
  44           12,   12,   12,   12,   12,   12,   11,   11,   11,   11,
  45           11,   11,   11,   11,   11,   10,   10,   10,   10,   10
  46     };
  47 
  48     int distanceValue() {
  49         if (max == INFINITE_DISTANCE) {
  50             return 0;
  51         }
  52         final int d = max - min;
  53         /* return dist_vals[d] * 16 / (mm->min + 12); */
  54         return d < distValues.length ? distValues[d] : 1;
  55     }
  56 
  57     int compareDistanceValue(final MinMaxLen other, final int v1p, final int v2p) {
  58         int v1 = v1p, v2 = v2p;
  59 
  60         if (v2 <= 0) {
  61             return -1;
  62         }
  63         if (v1 <= 0) {
  64             return 1;
  65         }
  66 
  67         v1 *= distanceValue();
  68         v2 *= other.distanceValue();
  69 
  70         if (v2 > v1) {
  71             return 1;
  72         }
  73         if (v2 < v1) {
  74             return -1;
  75         }
  76 
  77         if (other.min < min) {
  78             return 1;
  79         }
  80         if (other.min > min) {
  81             return -1;
  82         }
  83         return 0;
  84     }
  85 
  86     boolean equal(final MinMaxLen other) {
  87         return min == other.min && max == other.max;
  88     }
  89 
  90     void set(final int min, final int max) {
  91         this.min = min;
  92         this.max = max;
  93     }
  94 
  95     void clear() {
  96         min = max = 0;
  97     }
  98 
  99     void copy(final MinMaxLen other) {
 100         min = other.min;
 101         max = other.max;
 102     }
 103 
 104     void add(final MinMaxLen other) {
 105         min = distanceAdd(min, other.min);
 106         max = distanceAdd(max, other.max);
 107     }
 108 
 109     void addLength(final int len) {
 110         min = distanceAdd(min, len);
 111         max = distanceAdd(max, len);
 112     }
 113 
 114     void altMerge(final MinMaxLen other) {
 115         if (min > other.min) {
 116             min = other.min;
 117         }
 118         if (max < other.max) {
 119             max = other.max;
 120         }
 121     }
 122 
 123     static final int INFINITE_DISTANCE = 0x7FFFFFFF;
 124     static int distanceAdd(final int d1, final int d2) {
 125         if (d1 == INFINITE_DISTANCE || d2 == INFINITE_DISTANCE) {
 126             return INFINITE_DISTANCE;
 127         }
 128         if (d1 <= INFINITE_DISTANCE - d2) {
 129             return d1 + d2;
 130         }
 131         return INFINITE_DISTANCE;
 132     }
 133 
 134     static int distanceMultiply(final int d, final int m) {
 135         if (m == 0) {
 136             return 0;
 137         }
 138         if (d < INFINITE_DISTANCE / m) {
 139             return d * m;
 140         }
 141         return INFINITE_DISTANCE;
 142     }
 143 
 144     static String distanceRangeToString(final int a, final int b) {
 145         String s = "";
 146         if (a == INFINITE_DISTANCE) {
 147             s += "inf";
 148         } else {
 149             s += "(" + a + ")";
 150         }
 151 
 152         s += "-";
 153 
 154         if (b == INFINITE_DISTANCE) {
 155             s += "inf";
 156         } else {
 157             s += "(" + b + ")";
 158         }
 159         return s;
 160     }
 161 }