/// <summary>
/// Adds a string to the set if it does not already exist.
/// </summary>
/// <param name="buffer">The character array which represents the string you want to add.</param>
/// <param name="start">The index in the character array where your string starts.</param>
/// <param name="count">The length of the string you want to add.</param>
/// <param name="str">The string object representation of the characters. A new string is only allocated when it does not already exist in the set.</param>
/// <param name="knownHashValue">(optional) If the StringHash has already been calculated, you can provide it here to save re-calculation.</param>
/// <returns>True if the string was added. False if the string already existed in the set.</returns>
public bool Add(char[] buffer, int start, int count, out string str, StringHash knownHashValue = default(StringHash))
{
if (knownHashValue == default(StringHash))
{
knownHashValue = StringHash.GetHash(buffer, start, count);
}
else
{
StringHash.AssertBufferArgumentsAreSane(buffer.Length, start, count);
}
str = GetExistingStringImpl(buffer, start, count, knownHashValue);
if (str != null)
{
return(false); // didn't add anything
}
// an existing string wasn't found, we need to add it to the hash
lock (_writeLock)
{
// first, check one more time to see if it exists
str = GetExistingStringImpl(buffer, start, count, knownHashValue);
if (str == null)
{
// it definitely doesn't exist. Let's add it
str = new string(buffer, start, count);
AddImpl(str, knownHashValue);
return(true);
}
return(false);
}
}
/// <summary>
/// Uses the characters from a buffer to check whether a string exists in the set, and retrieve it if so.
/// </summary>
/// <param name="buffer">The character array which represents the string you want to check for.</param>
/// <param name="start">The index in the character array where your string starts.</param>
/// <param name="count">The length of the string you want to check for.</param>
/// <param name="knownHashValue">(optional) If the StringHash has already been calculated, you can provide it here to save re-calculation.</param>
/// <returns>If found in the set, the existing string is returned. If not found, null is returned.</returns>
public string GetExistingString(char[] buffer, int start, int count, StringHash knownHashValue = default(StringHash))
{
if (knownHashValue == default(StringHash))
{
knownHashValue = StringHash.GetHash(buffer, start, count);
}
else
{
StringHash.AssertBufferArgumentsAreSane(buffer.Length, start, count);
}
return(GetExistingStringImpl(buffer, start, count, knownHashValue));
}