/// <summary>
/// Determines if a substring of the current string instance
/// starts with the target string (or a substring of this target string) specified by <paramref name="target" />.
/// </summary>
/// <param name="source">This string instance.</param>
/// <param name="startIndex">The start position of the substring of the current string instance.</param>
/// <param name="target">The target string instance to compare.</param>
/// <param name="targetStartIndex">The start position of the substring of the target string instance.</param>
/// <param name="targetLength">The length of the substring of the target string specified by <paramref name="target" />.</param>
/// <param name="comparisonType">One of the enumeration values that specifies the rules for the comparison.</param>
/// <returns>
/// <c>true</c> if the specified substring starts with the target substring (or a substring of this target string); otherwise, <c>false</c>.
/// </returns>
/// <exception cref="System.ArgumentOutOfRangeException">
/// Occurs when at least one of <paramref name="startIndex"/>, <paramref name="targetStartIndex"/> and <paramref name="targetLength"/> is assigned an invalid value.
/// </exception>
/// <exception cref="System.ArgumentNullException">Occurs when the argument <paramref name="target"/> is <c>null</c>.</exception>
public static bool StartsWith(this string source, int startIndex, string target, int targetStartIndex, int targetLength, StringComparison comparisonType)
{
if (targetLength < 0)
{
throw new ArgumentOutOfRangeException(ExceptionHelper.GetNonNegativeArgumentRequiredMessage("targetLength"));
}
if (targetStartIndex < 0)
{
throw new ArgumentOutOfRangeException(ExceptionHelper.GetNonNegativeArgumentRequiredMessage("targetStartIndex"));
}
var realTargetLen = target?.Length ?? 0;
var targetEndIndex = targetStartIndex + targetLength;
if (targetEndIndex > realTargetLen)
{
throw new ArgumentOutOfRangeException(ExceptionHelper.GetArgumentOutOfRangeMessage("targetLength", 0, true, target.Length - targetStartIndex, true));
}
var sourceLen = source.Length;
if (startIndex < 0 && startIndex >= sourceLen)
{
throw new ArgumentOutOfRangeException(ExceptionHelper.GetArgumentOutOfRangeMessage("startIndex", 0, true, sourceLen, false));
}
sourceLen -= startIndex;
return(sourceLen >= targetLength && string.Compare(source, startIndex, target, targetStartIndex, targetLength, comparisonType) == 0);
}
/// <summary>
/// Reports the index of the last character satisfying the specified predicate.
/// The search starts at a specified character position and examines a specified number of character positions toward the beginning of this string instance.
/// </summary>
/// <param name="str">This string instance.</param>
/// <param name="predicate">A function to test each character of the current string.</param>
/// <param name="startIndex">The search starting position. The search proceeds from <paramref name="startIndex" /> toward the beginning of this instance.</param>
/// <param name="count">The number of character positions to examine.</param>
/// <returns>
/// The zero-based index position of the last character in this instance satisfying the specified predicate.
/// </returns>
public static int LastIndexOf(this string str, Func <char, bool> predicate, int startIndex, int count)
{
if (count < 0)
{
throw new ArgumentOutOfRangeException(ExceptionHelper.GetNonNegativeArgumentRequiredMessage("count"));
}
if (startIndex < 0)
{
throw new ArgumentOutOfRangeException(ExceptionHelper.GetArgumentOutOfRangeMessage("startIndex", 0, true, str.Length - 1, true));
}
var endIndex = startIndex - count;
if (endIndex < 0)
{
throw new ArgumentOutOfRangeException(ExceptionHelper.GetArgumentOutOfRangeMessage("count", 0, true, startIndex, true));
}
for (var i = startIndex; i >= endIndex; --i)
{
if (predicate(str[i]))
{
return(i);
}
}
return(-1);
}
/// <summary>
/// Determines if a substring of the current string instance
/// ends with the target string (or a substring of this target string) specified by <paramref name="target" />.
/// </summary>
/// <param name="source">This string instance.</param>
/// <param name="endIndex">The end position of the substring of the current string instance.</param>
/// <param name="target">The target string instance to compare.</param>
/// <param name="targetStartIndex">The start position of the substring of the target string instance.</param>
/// <param name="targetLength">The length of the substring of the target string specified by <paramref name="target" />.</param>
/// <param name="comparisonType">One of the enumeration values that specifies the rules for the comparison.</param>
/// <returns>
/// <c>true</c> if the specified substring ends with the target substring (or a substring of this target string); otherwise, <c>false</c>.
/// </returns>
/// <exception cref="System.ArgumentOutOfRangeException">
/// Occurs when at least one of <paramref name="endIndex"/>, <paramref name="targetStartIndex"/> and <paramref name="targetLength"/> is assigned an invalid value.
/// </exception>
/// <exception cref="System.ArgumentNullException">Occurs when the argument <paramref name="target"/> is <c>null</c>.</exception>
public static bool EndsWith(this string source, int endIndex, string target, int targetStartIndex, int targetLength, StringComparison comparisonType)
{
if (targetLength < 0)
{
throw new ArgumentOutOfRangeException(ExceptionHelper.GetNonNegativeArgumentRequiredMessage("targetLength"));
}
if (targetStartIndex < 0)
{
throw new ArgumentOutOfRangeException(ExceptionHelper.GetNonNegativeArgumentRequiredMessage("targetStartIndex"));
}
var realTargetLen = target == null ? 0 : target.Length;
var targetEndIndex = targetStartIndex + targetLength;
if (targetEndIndex > realTargetLen)
{
throw new ArgumentOutOfRangeException(ExceptionHelper.GetArgumentOutOfRangeMessage("targetLength", 0, true, target.Length - targetStartIndex, true));
}
var sourceLen = source.Length;
if (endIndex < 0 && endIndex >= sourceLen)
{
throw new ArgumentOutOfRangeException(ExceptionHelper.GetArgumentOutOfRangeMessage("startIndex", 0, true, sourceLen, false));
}
if (targetLength != 0 && targetLength != 1)
{
endIndex -= (targetLength - 1);
}
if (endIndex < 0)
{
return(false);
}
return(string.Compare(source, endIndex, target, targetStartIndex, targetLength, comparisonType) == 0);
}
