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[uuid] diegotorres/dtorres.py@gmail.com Improvements for UUIDv5 generation (#10978)

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* [uuid] Added method to generate UUID identifiers for version 5

Signed-off-by: Diego Torres <dtorres.py@gmail.com>

* [uuid] Small improvements for UUIDv5 generation

Signed-off-by: Diego Torres <dtorres.py@gmail.com>
This commit is contained in:
Diego Torres
2021-06-29 04:46:32 -04:00
committed by GitHub
parent f440eba4b7
commit c9882f2090
2 changed files with 8 additions and 15 deletions
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19
core-java-modules/core-java/src/main/java/com/baeldung/uuid/UUIDGenerator.java
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@@ -176,8 +176,8 @@ public class UUIDGenerator {
byte[] hash = md.digest(bytes);
long msb = peekLong(hash, 0, ByteOrder.BIG_ENDIAN);
long lsb = peekLong(hash, 8, ByteOrder.BIG_ENDIAN);
long msb = getLeastAndMostSignificantBitsVersion5(hash, 0);
long lsb = getLeastAndMostSignificantBitsVersion5(hash, 8);
// Set the version field
msb &= ~(0xfL << 12);
msb |= ((long) 5) << 12;
@@ -191,18 +191,11 @@ public class UUIDGenerator {
}
}
private static long peekLong(final byte[] src, final int offset, final ByteOrder order) {
private static long getLeastAndMostSignificantBitsVersion5(final byte[] src, final int offset) {
long ans = 0;
if (order == ByteOrder.BIG_ENDIAN) {
for (int i = offset; i < offset + 8; i += 1) {
ans <<= 8;
ans |= src[i] & 0xffL;
}
} else {
for (int i = offset + 7; i >= offset; i -= 1) {
ans <<= 8;
ans |= src[i] & 0xffL;
}
for (int i = offset + 7; i >= offset; i -= 1) {
ans <<= 8;
ans |= src[i] & 0xffL;
}
return ans;
}