FileNameSplit function for ColdFusion/Lucee - Split filename into base and extension

fileNameSplit.cfm

<!---
    FILENAMESPLIT Function
    
    Description: Splits a filename into base name and extension. The extension is everything from the 
    last dot to the end, including the dot. Special cases like hidden files (.bashrc) are handled correctly.
    
    Parameters:
        - path: The file path or filename to split (required)
    
    Returns: Array with two elements [basename, extension]
    
    Usage:
        <cfset result = fileNameSplit("document.pdf")>
        <cfset result = fileNameSplit("/path/to/file.txt")>
        <cfset result = fileNameSplit("archive.tar.gz")>
    
    Examples:
        fileNameSplit("document.pdf") returns ["document", ".pdf"]
        fileNameSplit("archive.tar.gz") returns ["archive.tar", ".gz"]
        fileNameSplit("README") returns ["README", ""]
        fileNameSplit(".bashrc") returns [".bashrc", ""]
        fileNameSplit("file.") returns ["file.", ""]
    
    Author: DeveloperOffice.com
    Language: ColdFusion/Lucee
    License: MIT (https://opensource.org/licenses/MIT)
    Version: 1.0
--->

<cffunction name="fileNameSplit" returntype="array" output="false">
    <cfargument name="path" type="string" required="true">
    
    <cfset var result = []>
    <cfset var filename = "">
    <cfset var lastSlashPos = 0>
    <cfset var dotPos = 0>
    <cfset var basename = "">
    <cfset var extension = "">
    
    <!--- Extract just the filename from the path ----->
    <cfset lastSlashPos = max(
        lastIndexOf(arguments.path, "/"),
        lastIndexOf(arguments.path, "\")
    )>
    
    <cfif lastSlashPos GT 0>
        <cfset filename = mid(arguments.path, lastSlashPos + 1, len(arguments.path) - lastSlashPos)>
        <cfset var pathPrefix = left(arguments.path, lastSlashPos)>
    <cfelse>
        <cfset filename = arguments.path>
        <cfset var pathPrefix = "">
    </cfif>
    
    <!--- Find the last dot in the filename ----->
    <cfset dotPos = lastIndexOf(filename, ".")>
    
    <!--- Handle special cases ----->
    <cfif dotPos EQ 0>
        <!--- No dot found ----->
        <cfset basename = arguments.path>
        <cfset extension = "">
    <cfelseif dotPos EQ 1>
        <!--- File starts with dot (hidden file like .bashrc) ----->
        <cfset basename = arguments.path>
        <cfset extension = "">
    <cfelseif dotPos EQ len(filename)>
        <!--- File ends with dot ----->
        <cfset basename = arguments.path>
        <cfset extension = "">
    <cfelse>
        <!--- Normal case: split at the last dot ----->
        <cfif lastSlashPos GT 0>
            <!--- Include the path prefix in basename ----->
            <cfset basename = pathPrefix & left(filename, dotPos - 1)>
        <cfelse>
            <cfset basename = left(filename, dotPos - 1)>
        </cfif>
        <cfset extension = mid(filename, dotPos, len(filename) - dotPos + 1)>
    </cfif>
    
    <!--- Return as array ----->
    <cfset arrayAppend(result, basename)>
    <cfset arrayAppend(result, extension)>
    
    <cfreturn result>
</cffunction>

<!--- Helper function for finding last occurrence of a string ----->
<cffunction name="lastIndexOf" returntype="numeric" output="false" access="private">
    <cfargument name="string" type="string" required="true">
    <cfargument name="substring" type="string" required="true">
    
    <cfset var pos = 0>
    <cfset var lastPos = 0>
    <cfset var searchFrom = 1>
    
    <cfloop condition="true">
        <cfset pos = find(arguments.substring, arguments.string, searchFrom)>
        <cfif pos EQ 0>
            <cfbreak>
        </cfif>
        <cfset lastPos = pos>
        <cfset searchFrom = pos + 1>
    </cfloop>
    
    <cfreturn lastPos>
</cffunction>