/**
*
*/
package net.varkhan.base.containers.array;
import java.io.IOException;
/**
* <b>Static short arrays manipulation utilities.</b>
* <p/>
* Utilities for manipulating arrays of shorts.
* <p/>
*
* @author varkhan
* @date Nov 15, 2010
* @time 12:06:41 AM
*/
public class ShortArrays {
/**
* Private empty constructor that forbids instantiation of this class.
*/
protected ShortArrays() {
}
/*********************************************************************************
** Matching operations
**/
/**
* Indicates whether two short arrays are equal.
*
* @param array1 the first array
* @param array2 the second array
*
* @return {@code true} iff the arrays are either both {@code null} or
* have the same number of elements, and the values of elements in the
* same positions are equal
*/
public static boolean equals(short[] array1, short[] array2) {
if(array1==null) return array2==null;
if(array1.length!=array2.length) return false;
for(int i=0;i<array1.length;i++) {
if(array1[i]!=array2[i]) return false;
}
return true;
}
/**
* Returns the position of the first occurrence of a value inside an array.
*
* @param item the value to search for
* @param array the array to search
*
* @return {@literal -1} if {@code item} was not found in {@code array},
* the position of the first element of the array equal to {@code item}
*/
public static int indexOf(short item, short... array) {
if(array==null) return -1;
final int length = array.length;
for(int i=0;i<length;i++) if(item==array[i]) return i;
return -1;
}
/**
* Returns the position of the first occurrence of an array as a subsequence
* of an other array.
*
* @param sub the subsequence to find
* @param pos the starting point in the array
* @param array the array
*
* @return the smallest index {@code idx} greater than {@code pos} such that
* the elements of {@code array} starting at {@code idx} are exactly those of
* {@code sub} ({@code -1} is returned if {@code sub} is not a subsequence
* of {@code array})
*/
public static int indexOf(short[] sub, int pos, short[] array) {
if(array==null) return sub==null ? 0 : -1;
match:
while(pos<array.length) {
for(int i=0;i<sub.length;i++) {
if(pos+i>=array.length) return -1;
if(array[pos+i]!=sub[i]) {
pos++;
continue match;
}
}
return pos;
}
return -1;
}
/*********************************************************************************
** Sorting and search
**/
/**
* Sorts an array in place, in ascending order.
*
* @param ary the array to sort
* @return the number of swap operations required for the sorting
*/
public static int sortInc(short... ary) {
return sortInc(ary, 0, ary.length-1);
}
/**
* Sorts an array in place, in descending order.
*
* @param ary the array to sort
* @return the number of swap operations required for the sorting
*/
public static int sortDec(short... ary) {
return sortDec(ary, 0, ary.length-1);
}
/**
* Sorts an array segment in place, in ascending order.
*
* @param ary the array to sort
* @param inf the minimum index
* @param sup the maximum index
* @return the number of swap operations required for the sorting
*/
public static int sortInc(short[] ary, int inf, int sup) {
int cnt = 0;
int beg = ((inf+sup)>>1)+1; // inf + (sup-inf+1)/2 - 1 = (sup+inf)/2+1
while(beg>inf) {
beg --;
cnt += heapDownInc(ary,beg,sup);
}
int end = sup;
while(end>=inf) {
short v = ary[end];
ary[end] = ary[inf];
ary[inf] = v;
end --;
cnt += 1 + heapDownInc(ary,inf,end);
}
return cnt;
}
/**
* Sorts an array segment in place, in descending order.
*
* @param ary the array to sort
* @param inf the minimum index
* @param sup the maximum index
* @return the number of swap operations required for the sorting
*/
public static int sortDec(short[] ary, int inf, int sup) {
int cnt = 0;
int beg = ((inf+sup)>>1)+1; // inf + (sup-inf+1)/2 - 1 = (sup+inf)/2+1
while(beg>inf) {
beg --;
cnt += heapDownDec(ary,beg,sup);
}
int end = sup;
while(end>=inf) {
short v = ary[end];
ary[end] = ary[inf];
ary[inf] = v;
end --;
cnt += 1 + heapDownDec(ary,inf,end);
}
return cnt;
}
protected static int heapDownInc(short[] ary, int inf, int sup) {
int cnt = 0;
int pos = inf;
int cld = (pos<<1)+1;
while(cld<=sup) {
int swp = pos;
if(ary[swp]<ary[cld]) swp = cld;
cld ++;
if(cld<=sup) {
if(ary[swp]<ary[cld]) swp = cld;
}
if(swp==pos) return cnt;
short v = ary[pos];
ary[pos] = ary[swp];
ary[swp] = v;
cnt ++;
pos = swp;
cld = (pos<<1)+1;
}
return cnt;
}
protected static int heapDownDec(short[] ary, int inf, int sup) {
int cnt = 0;
int pos = inf;
int cld = (pos<<1)+1;
while(cld<=sup) {
int swp = pos;
if(ary[swp]>ary[cld]) swp = cld;
cld ++;
if(cld<=sup) {
if(ary[swp]>ary[cld]) swp = cld;
}
if(swp==pos) return cnt;
short v = ary[pos];
ary[pos] = ary[swp];
ary[swp] = v;
cnt ++;
pos = swp;
cld = (pos<<1)+1;
}
return cnt;
}
/**
* Finds an object in a sorted array, in ascending order.
*
* @param ary the sorted array
* @param inf the minimum index
* @param sup the maximum index
* @param key the value to search for
*
* @return the key position in the array, or {@code -(inspos+1)},
* where {@code inspos} is the index of the first value in the
* array bigger than {@code key}
*/
public static int searchInc(short[] ary, int inf, int sup, short key) {
int min=inf;
int max=sup-1;
while(min<=max) {
int med=(min+max)>>>1;
short medVal=ary[med];
if(medVal<key) min=med+1;
else if(medVal>key) max=med-1;
else return med; // key found
}
return -(min+1); // key not found.
}
/**
* Finds an object in a sorted array, in descending order.
*
* @param ary the sorted array
* @param inf the minimum index
* @param sup the maximum index
* @param key the value to search for
*
* @return the key position in the array, or {@code -(inspos+1)},
* where {@code inspos} is the index of the first value in the
* array bigger than {@code key}
*/
public static int searchDec(short[] ary, int inf, int sup, short key) {
int min=inf;
int max=sup-1;
while(min<=max) {
int med=(min+max)>>>1;
short medVal=ary[med];
if(medVal<key) min=med+1;
else if(medVal>key) max=med-1;
else return med; // key found
}
return -(min+1); // key not found.
}
/**
* Computes the union of segments in two sorted arrays, in ascending order.
*
* @param ary1 the first sorted array
* @param beg1 the start position of the first segment
* @param len1 the length of the first segment
* @param ary2 the second sorted array
* @param beg2 the start position of the second segment
* @param len2 the length of the second segment
* @return the union of the two segments, with duplicates removed
*/
public static short[] unionInc(short[] ary1, int beg1, int len1, short[] ary2, int beg2, int len2) {
int len = len1+len2;
short[] union = new short[len];
if(len==0) return union;
short last = 0;
len1+=beg1;
len2+=beg2;
int beg=0;
while(beg1<len1 && beg2<len2) {
short val1 = ary1[beg1];
short val2 = ary2[beg2];
if(val1<val2) {
if(beg==0||last<val1) last = union[beg++] = val1;
beg1++;
} else
if(val1>val2) {
if(beg==0||last<val2) last = union[beg++] = val2;
beg2++;
} else {
if(beg==0||last<val1) last = union[beg++] = val1;
beg1++; beg2++;
}
}
while(beg1<len1) {
short val1 = ary1[beg1];
if(beg==0||last<val1) last = union[beg++] = val1;
beg1++;
}
while(beg2<len2) {
short val2 = ary2[beg2];
if(beg==0||last<val2) last = union[beg++] = val2;
beg2++;
}
if(beg>=len) return union;
short[] copy = new short[beg];
System.arraycopy(union, 0, copy, 0, beg);
return copy;
}
/**
* Computes the union of segments in two sorted arrays, in descending order.
*
* @param ary1 the first sorted array
* @param beg1 the start position of the first segment
* @param len1 the length of the first segment
* @param ary2 the second sorted array
* @param beg2 the start position of the second segment
* @param len2 the length of the second segment
* @return the union of the two segments, with duplicates removed
*/
public static short[] unionDec(short[] ary1, int beg1, int len1, short[] ary2, int beg2, int len2) {
int len = len1+len2;
short[] union = new short[len];
if(len==0) return union;
short last = 0;
len1+=beg1;
len2+=beg2;
int beg=0;
while(beg1<len1 && beg2<len2) {
short val1 = ary1[beg1];
short val2 = ary2[beg2];
if(val1>val2) {
if(beg==0||last>val1) last = union[beg++] = val1;
beg1++;
} else
if(val1<val2) {
if(beg==0||last>val1) last = union[beg++] = val2;
beg2++;
} else {
if(beg==0||last>val1) last = union[beg++] = val1;
beg1++; beg2++;
}
}
while(beg1<len1) {
short val1 = ary1[beg1];
if(beg==0||last>val1) last = union[beg++] = val1;
beg1++;
}
while(beg2<len2) {
short val2 = ary2[beg2];
if(beg==0||last>val2) last = union[beg++] = val2;
beg2++;
}
if(beg>=len) return union;
short[] copy = new short[beg];
System.arraycopy(union, 0, copy, 0, beg);
return copy;
}
/**
* Computes the intersection of segments in two sorted arrays, in ascending order.
*
* @param ary1 the first sorted array
* @param beg1 the start position of the first segment
* @param len1 the length of the first segment
* @param ary2 the second sorted array
* @param beg2 the start position of the second segment
* @param len2 the length of the second segment
* @return the intersection of the two segments, with duplicates removed
*/
public static short[] interInc(short[] ary1, int beg1, int len1, short[] ary2, int beg2, int len2) {
int len = (len1>len2)?len1:len2;
short[] inter = new short[len];
if(len==0) return inter;
short last = 0;
len1+=beg1;
len2+=beg2;
int beg=0;
while(beg1<len1 && beg2<len2) {
short val1 = ary1[beg1];
short val2 = ary2[beg2];
if(val1<val2) { beg1++; } else
if(val1>val2) { beg2++; } else
{ if(beg==0||last<val1) last = inter[beg++] = val1; beg1++; beg2++; }
}
if(beg>=len) return inter;
short[] copy = new short[beg];
System.arraycopy(inter, 0, copy, 0, beg);
return copy;
}
/**
* Computes the intersection of segments in two sorted arrays, in descending order.
*
* @param ary1 the first sorted array
* @param beg1 the start position of the first segment
* @param len1 the length of the first segment
* @param ary2 the second sorted array
* @param beg2 the start position of the second segment
* @param len2 the length of the second segment
* @return the intersection of the two segments, with duplicates removed
*/
public static short[] interDec(short[] ary1, int beg1, int len1, short[] ary2, int beg2, int len2) {
int len = (len1>len2)?len1:len2;
short[] inter = new short[len];
if(len==0) return inter;
short last = 0;
len1+=beg1;
len2+=beg2;
int beg=0;
while(beg1<len1 && beg2<len2) {
short val1 = ary1[beg1];
short val2 = ary2[beg2];
if(val1>val2) { beg1++; } else
if(val1<val2) { beg2++; } else
{ if(beg==0||last>val1) last = inter[beg++] = val1; beg1++; beg2++; }
}
if(beg>=len) return inter;
short[] copy = new short[beg];
System.arraycopy(inter, 0, copy, 0, beg);
return copy;
}
/*********************************************************************************
** Copy and concatenation
**/
/**
* Append elements to an array.
*
* @param array the array to append to
* @param elems the elements to append
*
* @return an array of shorts containing all the elements of {@code array} followed by all the elements in {@code elems}
*/
public static short[] append(short[] array, short... elems) {
short[] concat=new short[array.length+elems.length];
System.arraycopy(array, 0, concat, 0, array.length);
System.arraycopy(elems, 0, concat, array.length, elems.length);
return concat;
}
/**
* Prepend elements to an array.
*
* @param array the array to prepend to
* @param elems the elements to prepend
*
* @return an array of shorts containing all the elements in {@code elems} followed by all the elements of {@code array}
*/
public static short[] prepend(short[] array, short... elems) {
short[] concat=new short[array.length+elems.length];
System.arraycopy(elems, 0, concat, 0, elems.length);
System.arraycopy(array, 0, concat, elems.length, array.length);
return concat;
}
/**
* Concatenates several arrays.
*
* @param array the first array to append to
* @param arrays the arrays to append
*
* @return an array of shorts containing all the elements in the arrays, in order
*/
public static short[] concat(short[] array, short[]... arrays) {
int l=array.length;
for(short[] t : arrays) { l+=t.length; }
short[] concat=new short[l];
System.arraycopy(array, 0, concat, 0, array.length);
l=array.length;
for(short[] t : arrays) {
System.arraycopy(t, 0, concat, l, t.length);
l+=t.length;
}
return concat;
}
/**
* Returns a segment of an array.
*
* @param array the source array
* @param beg the begining position of the segment, inclusive
* @param end the ending position of the segment, exclusive
*
* @return an array of shorts, of length {@code end-beg}, and containing all the
* elements between positions {@code beg}, inclusive, and {@code end}, exclusive,
* of the original array
*/
public static short[] subarray(short[] array, int beg, int end) {
int l=array.length;
if(beg<0 || beg>end || end>l) throw new ArrayIndexOutOfBoundsException("["+beg+":"+end+"] is not a valid range specifier");
short[] subary=new short[end-beg];
if(end>beg) System.arraycopy(array, beg, subary, 0, end-beg);
return subary;
}
/*********************************************************************************
** String transformation
**/
/**
* Builds a pretty string representation of a short array.
*
* @param buf the buffer to append the composed string to
* @param array the short array to stringify
*
* @return the original buffer, for chaining purposes
*
* @throws java.io.IOException if the output buffer raises this exception on {@code append()}
*/
public static <A extends Appendable> A toString(A buf, short[] array) throws IOException {
buf.append("[").append(Integer.toString(array.length)).append("|");
for(int i=0;i<array.length;i++) {
if(i>0) buf.append(",");
buf.append(Integer.toString(array[i]));
}
buf.append("]");
return buf;
}
/**
* Builds a pretty string representation of a short array.
*
* @param buf the buffer to append the composed string to
* @param array the short array to stringify
*
* @return the original buffer, for chaining purposes
*/
public static StringBuilder toString(StringBuilder buf, short[] array) {
buf.append("[").append(array.length).append("|");
for(int i=0;i<array.length;i++) {
if(i>0) buf.append(",");
buf.append(Integer.toString(array[i]));
}
buf.append("]");
return buf;
}
/**
* Returns a pretty string representation of a short array.
*
* @param array the short array to stringify
*
* @return a human-readable string exposing the contents of the array
*/
public static String toString(short[] array) {
return toString(new StringBuilder(), array).toString();
}
/**
* Appends as strings the elements of a short array, separating them with a given string.
*
* @param buf the buffer to append the composed string to
* @param sep the separator to use
* @param array the short array to concatenate
*
* @return the original buffer, for chaining purposes
*
* @throws IOException if the output buffer raises this exception on {@code append()}
*/
public static <A extends Appendable> A join(A buf, String sep, short[] array) throws IOException {
if(sep==null) for(int i=0;i<array.length;i++) {
buf.append(Integer.toString(array[i]));
}
else for(int i=0;i<array.length;i++) {
if(i>0) buf.append(sep);
buf.append(Integer.toString(array[i]));
}
return buf;
}
/**
* Appends as strings the elements of a short array, separating them with a given string.
*
* @param buf the buffer to append the composed string to
* @param sep the separator to use
* @param array the short array to concatenate
*
* @return the original buffer, for chaining purposes
*/
public static StringBuilder join(StringBuilder buf, String sep, short[] array) {
if(sep==null) for(int i=0;i<array.length;i++) {
buf.append(Integer.toString(array[i]));
}
else for(int i=0;i<array.length;i++) {
if(i>0) buf.append(sep);
buf.append(Integer.toString(array[i]));
}
return buf;
}
/**
* Appends as strings the elements of a short array, separating them with a given string.
*
* @param sep the separator to use
* @param array the short array to concatenate
*
* @return a concatenation of the elements of the array, as string, and the separator
*/
public static String join(String sep, short[] array) {
return join(new StringBuilder(), sep, array).toString();
}
}