Github user JoshRosen commented on a diff in the pull request:
https://github.com/apache/spark/pull/7197#discussion_r33830851
--- Diff:
unsafe/src/main/java/org/apache/spark/unsafe/types/UTF8String.java ---
@@ -106,92 +105,126 @@ public int length() {
* @param until the position after last code point, exclusive.
*/
public UTF8String substring(final int start, final int until) {
- if (until <= start || start >= bytes.length) {
+ if (until <= start || start >= size) {
return UTF8String.fromBytes(new byte[0]);
}
int i = 0;
int c = 0;
- for (; i < bytes.length && c < start; i += numBytes(bytes[i])) {
+ for (; i < size && c < start; i += numBytes(getByte(i))) {
c += 1;
}
int j = i;
- for (; j < bytes.length && c < until; j += numBytes(bytes[i])) {
+ for (; j < size && c < until; j += numBytes(getByte(i))) {
c += 1;
}
- return UTF8String.fromBytes(Arrays.copyOfRange(bytes, i, j));
+ byte[] bytes = new byte[j - i];
+ copyMemory(base, offset + i, bytes, BYTE_ARRAY_OFFSET, j - i);
+ return UTF8String.fromBytes(bytes);
}
public boolean contains(final UTF8String substring) {
- final byte[] b = substring.getBytes();
- if (b.length == 0) {
+ if (substring.size == 0) {
return true;
}
- for (int i = 0; i <= bytes.length - b.length; i++) {
- if (bytes[i] == b[0] && startsWith(b, i)) {
+ byte first = substring.getByte(0);
+ for (int i = 0; i <= size - substring.size; i++) {
+ if (getByte(i) == first && matchAt(substring, i)) {
return true;
}
}
return false;
}
- private boolean startsWith(final byte[] prefix, int offsetInBytes) {
- if (prefix.length + offsetInBytes > bytes.length || offsetInBytes < 0)
{
+ private long getLong(int i) {
+ return UNSAFE.getLong(base, offset + i);
+ }
+
+ private byte getByte(int i) {
+ return UNSAFE.getByte(base, offset + i);
+ }
+
+ private boolean matchAt(final UTF8String s, int pos) {
--- End diff --
The loops here in `matchAt`, could probably be replaced by a single call to
`ByteArrayMethods.arrayEquals`, provided that we make a non-word-aligned
version of that method. There is some example code in Guava that you could
base this on. We can defer this for later, too, but I figure that since we've
basically already written this method here then we might as well put it into a
place where it can be used more generically.
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