Github user Hexiaoqiao commented on a diff in the pull request:
https://github.com/apache/incubator-carbondata/pull/627#discussion_r104617853
--- Diff: core/src/main/java/org/apache/carbondata/core/util/ByteUtil.java
---
@@ -152,6 +152,159 @@ static boolean lessThanUnsigned(long x1, long x2) {
return (x1 + Long.MIN_VALUE) < (x2 + Long.MIN_VALUE);
}
+
+/* public static int binarySearch(byte[] a, int fromIndex, int
toIndex, byte[] key) {
+ int keyLength = key.length;
+ rangeCheck(a.length, fromIndex, toIndex, keyLength);
+ return binarySearch0(a, fromIndex, toIndex / keyLength,
key);
+ }
+
+ // Like public version, but without range checks.
+ private static int binarySearch0(byte[] a, int fromIndex, int
toIndex, byte[] key) {
+ int low = fromIndex;
+ int high = toIndex - 1;
+ int keyLength = key.length;
+ // int high = toIndex/keyLength;
+
+ while (low <= high) {
+ int mid = (low + high) >>> 1;
+ // byte midVal = a[mid];
+
+ int result =
ByteUtil.UnsafeComparer.INSTANCE.compareTo(a, mid * keyLength, keyLength, key,
0,
+ keyLength);
+
+ if (result < 0)
+ low = mid + keyLength;
+ else if (result > 0)
+ high = mid - keyLength;
+ else
+ return mid; // key found
+ }
+ return -(low + 1); // key not found.
+ }*/
+ /**
+ * Checks that {@code fromIndex} and {@code toIndex} are in the range
and toIndex % keyLength = 0
+ * and throws an exception if they aren't.
+ */
+ private static void rangeCheck(int arrayLength, int fromIndex, int
toIndex, int keyWordLength) {
+ if (fromIndex > toIndex || toIndex % keyWordLength != 0) {
+ throw new IllegalArgumentException("fromIndex(" +
fromIndex + ") > toIndex(" + toIndex + ")");
+ }
+ if (fromIndex < 0) {
+ throw new ArrayIndexOutOfBoundsException(fromIndex);
+ }
+ if (toIndex > arrayLength) {
+ throw new ArrayIndexOutOfBoundsException(toIndex);
+ }
+ }
+
+ /**
+ * search a specific key's range boundary in sorted byte array
+ *
+ * @param dataChunk
+ * @param fromIndex
+ * @param toIndex
+ * it's max value should be word Number in dataChunk, equal
to indataChunk.length/keyWord.length
+ * @param keyWord
+ * @return int[] contains a range's lower boundary and upper boundary
+ */
+ public static int[] binaryRangeSearch(byte[] dataChunk, int fromIndex,
int toIndex, byte[] keyWord) {
+
+
+ int keyLength = keyWord.length;
+ rangeCheck(dataChunk.length, fromIndex, toIndex, keyLength);
+
+ // reset to index = word total number in the dataChunk
+ toIndex = toIndex/keyWord.length;
+
+ int[] rangeIndex = new int[2];
+ int low = fromIndex;
+ int high = toIndex - 1;
+
+ while (low <= high) {
+ int mid = (low + high) >>> 1;
+
+ int result =
ByteUtil.UnsafeComparer.INSTANCE.compareTo(dataChunk, mid * keyLength,
keyLength, keyWord, 0,
+ keyLength);
+
+ if (result < 0)
+ low = mid + 1;
+ else if (result > 0)
+ high = mid - 1;
+ else {
+ // key found then find the range bound
+ rangeIndex[0] =
binaryRangeBoundarySearch(dataChunk, low, mid, keyWord, false);
+ rangeIndex[1] =
binaryRangeBoundarySearch(dataChunk, mid, high, keyWord, true);
+ return rangeIndex;
+ }
+
+ }
+ // key not found. return a not exist range
+ rangeIndex[0] = 0;
+ rangeIndex[1] = -1;
+ return rangeIndex;
+ }
+
+ /**
+ * use to search a specific keyword's lower boundary and upper boundary
according to upFindFlg
+ * @param dataChunk
+ * @param fromIndex
+ * @param toIndex
+ * @param keyWord
+ * @param upFindFlg true:find upper boundary false: find lower boundary
+ * @return boundary index
+ */
+ public static int binaryRangeBoundarySearch(byte[] dataChunk, int
fromIndex, int toIndex, byte[] keyWord, boolean upFindFlg) {
--- End diff --
1. there are some common codes between `binaryRangeSearch` and
`binaryRangeBoundarySearch`, is it possible to merge them into one method?
2. are you interesting to impl. a complete function about Interval (of
Mathematics).
FYI.
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