Returns the index of the nearest bit that is set to {@code true}
that occurs on or before the specified starting index.
If no such bit exists, or if {@code -1} is given as the
starting index, then {@code -1} is returned.
<p>To iterate over the {@code true} bits in a {@code BitSet},
use the following loop:
<pre> {@code
for (int i = bs.length(); (i = bs.previousSetBit(i-1)) >= 0; ) {
// operate on index i here
}}</pre>
@param fromIndex the index to start checking from (inclusive)
@return the index of the previous set bit, or {@code -1} if there
is no such bit
@throws IndexOutOfBoundsException if the specified index is less
than {@code -1}
Returns the index of the nearest bit that is set to {@code true} that occurs on or before the specified starting index. If no such bit exists, or if {@code -1} is given as the starting index, then {@code -1} is returned.
<p>To iterate over the {@code true} bits in a {@code BitSet}, use the following loop:
<pre> {@code for (int i = bs.length(); (i = bs.previousSetBit(i-1)) >= 0; ) { // operate on index i here }}</pre>
@param fromIndex the index to start checking from (inclusive) @return the index of the previous set bit, or {@code -1} if there is no such bit @throws IndexOutOfBoundsException if the specified index is less than {@code -1}