「Java」reverse()で文字列を反転させる方法

2017年5月20日

Javaコード
public AbstractStringBuilder reverse() {
boolean hasSurrogate = false;
int n = count – 1;
for (int j = (n-1) >> 1; j >= 0; –j) {
char temp = value[j];
char temp2 = value[n – j];
if (!hasSurrogate) {
hasSurrogate = (temp >= Character.MIN_SURROGATE && temp <= Character.MAX_SURROGATE)
|| (temp2 >= Character.MIN_SURROGATE && temp2 <= Character.MAX_SURROGATE);
}
value[j] = temp2;
value[n – j] = temp;
}
if (hasSurrogate) {
// Reverse back all valid surrogate pairs
for (int i = 0; i < count – 1; i++) {
char c2 = value[i];
if (Character.isLowSurrogate(c2)) {
char c1 = value[i + 1];
if (Character.isHighSurrogate(c1)) {
value[i++] = c1;
value[i] = c2;
}
}
}
}
return this;
}