/// <summary>
/// Attempts to find the value that is associated to a particular key.
/// </summary>
/// <typeparam name="TKey">The type of the key.</typeparam>
/// <typeparam name="TValue">The type of the value.</typeparam>
/// <param name="searchable">The <see cref="IBinarySearchable{TKey, TValue}"/> to search.</param>
/// <param name="key">The key to find.</param>
/// <param name="valueOrDefault">Upon success, assigned to the value that is associated to the
/// <paramref name="key"/>. Upon failure, assigned to the default <typeparamref name="TValue"/>
/// value.</param>
/// <param name="progressReporter"><see cref="IProgress{T}"/> that receives a <see cref="ProgressReport"/>
/// as the search progresses. May be null, in which case progress will not be reported.</param>
/// <param name="cancellationToken"><see cref="CancellationToken"/> that can be used to cancel the search
/// operation. Upon cancellation, false is returned.</param>
/// <returns>True if the <paramref name="key"/> was found, otherwise false. False indicates that the
/// <paramref name="key"/> was not present in this <see cref="IBinarySearchable{TKey, TValue}"/>, or that
/// the search was cancelled via the <paramref name="cancellationToken"/>.</returns>
/// <seealso cref="TryFindIndex{TKey, TValue}(IBinarySearchable{TKey, TValue}, TKey, out long, IProgress{ProgressReport}, CancellationToken)"/>
/// <seealso cref="IBinarySearchable{TKey, TValue}.GetValueAt(long)"/>
/// <seealso cref="TryFindCeiling{TKey, TValue}(IBinarySearchable{TKey, TValue}, TKey, out long, out TKey, IProgress{ProgressReport}, CancellationToken)"/>
/// <seealso cref="TryFindFloor{TKey, TValue}(IBinarySearchable{TKey, TValue}, TKey, out long, out TKey, IProgress{ProgressReport}, CancellationToken)"/>
public static bool TryFindValue <TKey, TValue>(this IBinarySearchable <TKey, TValue> searchable, TKey key, out TValue valueOrDefault, IProgress <ProgressReport> progressReporter = null, CancellationToken cancellationToken = default(CancellationToken)) where TKey : IComparable <TKey>
{
if (TryFindIndex(searchable, key, out long index, progressReporter, cancellationToken))
{
valueOrDefault = searchable.GetValueAt(index);
return(true);
}
/// <summary>
/// Attempts to find the index of a particular key.
/// </summary>
/// <typeparam name="TKey">The type of the key.</typeparam>
/// <typeparam name="TValue">The type of the value.</typeparam>
/// <param name="searchable">The <see cref="IBinarySearchable{TKey, TValue}"/> to search.</param>
/// <param name="key">The key to find.</param>
/// <param name="index">Upon success, assigned to the index where the <paramref name="key"/> was found.
/// Upon failure, assigned to -1.</param>
/// <param name="progressReporter"><see cref="IProgress{T}"/> that receives a <see cref="ProgressReport"/>
/// as the search progresses. May be null, in which case progress will not be reported.</param>
/// <param name="cancellationToken"><see cref="CancellationToken"/> that can be used to cancel the search
/// operation. Upon cancellation, false is returned.</param>
/// <returns>True if the <paramref name="key"/> was found, otherwise false. False indicates that the
/// <paramref name="key"/> was not present in this <see cref="IBinarySearchable{TKey, TValue}"/>, or that
/// the search was cancelled via the <paramref name="cancellationToken"/>.</returns>
/// <seealso cref="TryFindValue{TKey, TValue}(IBinarySearchable{TKey, TValue}, TKey, out TValue, IProgress{ProgressReport}, CancellationToken)"/>
/// <seealso cref="IBinarySearchable{TKey, TValue}.GetValueAt(long)"/>
/// <seealso cref="TryFindCeiling{TKey, TValue}(IBinarySearchable{TKey, TValue}, TKey, out long, out TKey, IProgress{ProgressReport}, CancellationToken)"/>
/// <seealso cref="TryFindFloor{TKey, TValue}(IBinarySearchable{TKey, TValue}, TKey, out long, out TKey, IProgress{ProgressReport}, CancellationToken)"/>
public static bool TryFindIndex <TKey, TValue>(this IBinarySearchable <TKey, TValue> searchable, TKey key, out long index, IProgress <ProgressReport> progressReporter = null, CancellationToken cancellationToken = default(CancellationToken)) where TKey : IComparable <TKey>
{
if (searchable == null)
{
throw new ArgumentNullException(nameof(searchable));
}
if (cancellationToken.Equals(default(CancellationToken)))
{
cancellationToken = new CancellationToken(false);
}
long start = 0, end = searchable.Count - 1;
long currentProgress = 0, maxProgress = CalculateSearchComplexity(searchable.Count);
while (start <= end)
{
long middle = start + ((end - start) / 2);
TKey current = searchable.GetKeyAt(middle);
int comparison = current.CompareTo(key);
currentProgress++;
progressReporter?.Report(new ProgressReport(currentProgress, maxProgress));
if (comparison == 0)
{
//Found it
index = middle;
progressReporter?.Report(new ProgressReport(maxProgress, maxProgress));
return(true);
}
else if (comparison < 0)
{
start = middle + 1;
}
else
{
end = middle - 1;
}
if (cancellationToken.IsCancellationRequested)
{
index = -1;
return(false);
}
}
//Not found
progressReporter?.Report(new ProgressReport(maxProgress, maxProgress));
index = -1;
return(false);
}