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[LANG-1548] split regionMatches for better performance #534

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[LANG-1548] split regionMatches for better performance #534

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73 changes: 65 additions & 8 deletions src/main/java/org/apache/commons/lang3/CharSequenceUtils.java
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Original file line number Diff line number Diff line change
Expand Up @@ -328,17 +328,58 @@ public static char[] toCharArray(final CharSequence source) {
* Green implementation of regionMatches.
*
* @param cs the {@code CharSequence} to be processed
* @param ignoreCase whether or not to be case insensitive
* @param thisStart the index to start on the {@code cs} CharSequence
* @param substring the {@code CharSequence} to be looked for
* @param start the index to start on the {@code substring} CharSequence
* @param length character length of the region
* @return whether the region matched
*/
static boolean regionMatches(final CharSequence cs, final boolean ignoreCase, final int thisStart,
final CharSequence substring, final int start, final int length) {
static boolean regionMatches(final CharSequence cs, final int thisStart,
final CharSequence substring, final int start, final int length) {
if (cs instanceof String && substring instanceof String) {
return ((String) cs).regionMatches(thisStart, (String) substring, start, length);
}
int index1 = thisStart;
int index2 = start;
int tmpLen = length;

// Extract these first so we detect NPEs the same as the java.lang.String version
final int srcLen = cs.length() - thisStart;
final int otherLen = substring.length() - start;

// Check for invalid parameters
if (thisStart < 0 || start < 0 || length < 0) {
return false;
}

// Check that the regions are long enough
if (srcLen < length || otherLen < length) {
return false;
}

while (tmpLen-- > 0) {
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if (cs.charAt(index1++) != substring.charAt(index2++)) {
return false;
}
}

return true;
}

/**
* Green implementation of regionMatches.
*
* @param cs the {@code CharSequence} to be processed
* @param thisStart the index to start on the {@code cs} CharSequence
* @param substring the {@code CharSequence} to be looked for
* @param start the index to start on the {@code substring} CharSequence
* @param length character length of the region
* @return whether the region matched
*/
static boolean regionMatchesIgnoreCase(final CharSequence cs, final int thisStart,
final CharSequence substring, final int start, final int length) {
if (cs instanceof String && substring instanceof String) {
return ((String) cs).regionMatches(ignoreCase, thisStart, (String) substring, start, length);
return ((String) cs).regionMatches(true, thisStart, (String) substring, start, length);
}
int index1 = thisStart;
int index2 = start;
Expand Down Expand Up @@ -366,10 +407,6 @@ static boolean regionMatches(final CharSequence cs, final boolean ignoreCase, fi
continue;
}

if (!ignoreCase) {
return false;
}

// The real same check as in String.regionMatches():
final char u1 = Character.toUpperCase(c1);
final char u2 = Character.toUpperCase(c2);
Expand All @@ -380,4 +417,24 @@ static boolean regionMatches(final CharSequence cs, final boolean ignoreCase, fi

return true;
}

/**
* Green implementation of regionMatches.
*
* @param cs the {@code CharSequence} to be processed
* @param ignoreCase whether or not to be case insensitive
* @param thisStart the index to start on the {@code cs} CharSequence
* @param substring the {@code CharSequence} to be looked for
* @param start the index to start on the {@code substring} CharSequence
* @param length character length of the region
* @return whether the region matched
*/
static boolean regionMatches(final CharSequence cs, final boolean ignoreCase, final int thisStart,
final CharSequence substring, final int start, final int length) {
if (!ignoreCase) {
return regionMatches(cs, thisStart, substring, start, length);
} else {
return regionMatchesIgnoreCase(cs, thisStart, substring, start, length);
}
}
}
8 changes: 4 additions & 4 deletions src/main/java/org/apache/commons/lang3/StringUtils.java
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Original file line number Diff line number Diff line change
Expand Up @@ -1241,7 +1241,7 @@ public static boolean containsIgnoreCase(final CharSequence str, final CharSeque
final int len = searchStr.length();
final int max = str.length() - len;
for (int i = 0; i <= max; i++) {
if (CharSequenceUtils.regionMatches(str, true, i, searchStr, 0, len)) {
if (CharSequenceUtils.regionMatchesIgnoreCase(str, i, searchStr, 0, len)) {
return true;
}
}
Expand Down Expand Up @@ -1909,7 +1909,7 @@ public static boolean equalsIgnoreCase(final CharSequence cs1, final CharSequenc
if (cs1.length() != cs2.length()) {
return false;
}
return CharSequenceUtils.regionMatches(cs1, true, 0, cs2, 0, cs1.length());
return CharSequenceUtils.regionMatchesIgnoreCase(cs1, 0, cs2, 0, cs1.length());
}

/**
Expand Down Expand Up @@ -3165,7 +3165,7 @@ public static int indexOfIgnoreCase(final CharSequence str, final CharSequence s
return startPos;
}
for (int i = startPos; i < endLimit; i++) {
if (CharSequenceUtils.regionMatches(str, true, i, searchStr, 0, searchStr.length())) {
if (CharSequenceUtils.regionMatchesIgnoreCase(str, i, searchStr, 0, searchStr.length())) {
return i;
}
}
Expand Down Expand Up @@ -5168,7 +5168,7 @@ public static int lastIndexOfIgnoreCase(final CharSequence str, final CharSequen
}

for (int i = startPos; i >= 0; i--) {
if (CharSequenceUtils.regionMatches(str, true, i, searchStr, 0, searchStrLength)) {
if (CharSequenceUtils.regionMatchesIgnoreCase(str, i, searchStr, 0, searchStrLength)) {
return i;
}
}
Expand Down