@Override
public int compareTo(@Nonnull final UTF8String other) {
int len = Math.min(numBytes, other.numBytes);
// TODO: compare 8 bytes as unsigned long
for (int i = 0; i < len; i++) {
// In UTF-8, the byte should be unsigned, so we should compare them as unsigned int.
int res = (getByte(i) & 0xFF) - (other.getByte(i) & 0xFF);
if (res != 0) {
return res;
}
}
return numBytes - other.numBytes;
}
/** Returns whether this contains `substring` or not. */
public boolean contains(final UTF8String substring) {
if (substring.numBytes == 0) {
return true;
}
byte first = substring.getByte(0);
for (int i = 0; i <= numBytes - substring.numBytes; i++) {
if (getByte(i) == first && matchAt(substring, i)) {
return true;
}
}
return false;
}
/**
* Levenshtein distance is a metric for measuring the distance of two strings. The distance is
* defined by the minimum number of single-character edits (i.e. insertions, deletions or
* substitutions) that are required to change one of the strings into the other.
*/
public int levenshteinDistance(UTF8String other) {
// Implementation adopted from org.apache.common.lang3.StringUtils.getLevenshteinDistance
int n = numChars();
int m = other.numChars();
if (n == 0) {
return m;
} else if (m == 0) {
return n;
}
UTF8String s, t;
if (n <= m) {
s = this;
t = other;
} else {
s = other;
t = this;
int swap;
swap = n;
n = m;
m = swap;
}
int[] p = new int[n + 1];
int[] d = new int[n + 1];
int[] swap;
int i, i_bytes, j, j_bytes, num_bytes_j, cost;
for (i = 0; i <= n; i++) {
p[i] = i;
}
for (j = 0, j_bytes = 0; j < m; j_bytes += num_bytes_j, j++) {
num_bytes_j = numBytesForFirstByte(t.getByte(j_bytes));
d[0] = j + 1;
for (i = 0, i_bytes = 0; i < n; i_bytes += numBytesForFirstByte(s.getByte(i_bytes)), i++) {
if (s.getByte(i_bytes) != t.getByte(j_bytes)
|| num_bytes_j != numBytesForFirstByte(s.getByte(i_bytes))) {
cost = 1;
} else {
cost =
(ByteArrayMethods.arrayEquals(
t.base, t.offset + j_bytes, s.base, s.offset + i_bytes, num_bytes_j))
? 0
: 1;
}
d[i + 1] = Math.min(Math.min(d[i] + 1, p[i + 1] + 1), p[i] + cost);
}
swap = p;
p = d;
d = swap;
}
return p[n];
}
