eu.interedition.collatex.suffixarray.Tools Maven / Gradle / Ivy
package eu.interedition.collatex.suffixarray;
/**
* Utility methods used throughout entire project.
*
* @author Michał Nowak (Carrot Search)
* @author Dawid Weiss (Carrot Search)
*/
final class Tools {
private Tools() {
// No instances.
}
/**
* Check if all symbols in the given range are greater than 0, return
* true if so, false otherwise.
*/
static final boolean allPositive(int[] input, int start, int length) {
for (int i = length - 1, index = start; i >= 0; i--, index++) {
if (input[index] <= 0) {
return false;
}
}
return true;
}
/**
* Determine the maximum value in a slice of an array.
*/
static final int max(int[] input, int start, int length) {
assert length >= 1;
int max = input[start];
for (int i = length - 2, index = start + 1; i >= 0; i--, index++) {
final int v = input[index];
if (v > max) {
max = v;
}
}
return max;
}
/**
* Determine the minimum value in a slice of an array.
*/
static final int min(int[] input, int start, int length) {
assert length >= 1;
int min = input[start];
for (int i = length - 2, index = start + 1; i >= 0; i--, index++) {
final int v = input[index];
if (v < min) {
min = v;
}
}
return min;
}
/**
* Calculate minimum and maximum value for a slice of an array.
*/
static MinMax minmax(int[] input, final int start, final int length) {
int max = input[start];
int min = max;
for (int i = length - 2, index = start + 1; i >= 0; i--, index++) {
final int v = input[index];
if (v > max) {
max = v;
}
if (v < min) {
min = v;
}
}
return new MinMax(min, max);
}
/**
* Throw {@link AssertionError} if a condition is false. This should
* be called when the assertion must be always verified (as in the case of verifying
* the algorithm's preconditions). For other, internal assertions, one should use
* assert keyword so that such assertions can be disabled at run-time (for
* performance reasons).
*/
static final void assertAlways(boolean condition, String msg) {
if (!condition) {
throw new AssertionError(msg);
}
}
}