/// <summary>
/// Diff the given columns of two given files using a given tolerance and method reporting any information back to the StringBuilder passed by ref
/// </summary>
/// <param name="origfile">the original file</param>
/// <param name="newfile">the new file to diff against the original file</param>
/// <param name="colnames">the colnames to focus on</param>
/// <param name="tolerance">the toleracne to use (absolute value/dp/%age depedning on 'method')</param>
/// <param name="method">the method to use when diffing (absolute value/dp/%age)</param>
/// <param name="output">a StringBuilder for reporting</param>
/// <returns>true if files are approximately the same (within the given tolerance)</returns>
internal static bool Diff(InputFile origfile, InputFile newfile, List <string> colnames, decimal tolerance, DiffMethod method, ref StringBuilder output)
{
Dictionary <string, int>
orig_lookup = new Dictionary <string, int>(),
new_lookup = new Dictionary <string, int>();
List <string>
orig_cols = new List <string>(origfile.ColNames),
new_cols = new List <string>(newfile.ColNames);
//basic little factory for setting up our comparer object
CompareMethod comparer =
method == DiffMethod.pct ? (CompareMethod) new PctCompare(tolerance) :
method == DiffMethod.abs ? (CompareMethod) new AbsCompare(tolerance) :
(CompareMethod) new DPCompare(tolerance);
//set up a lookup dictionary to translate between column name and index
foreach (string col in colnames)
{
orig_lookup.Add(col, orig_cols.IndexOf(col));
new_lookup.Add(col, new_cols.IndexOf(col));
}
//grab the raw data to diff
object[][]
origdata = origfile.GetData(true),
newdata = newfile.GetData(true);
string result = "";
if (origdata.Length != newdata.Length)
{
result += "The 2 files had different lengths, diff will end at bottom of shortest file" + Environment.NewLine;
}
object diff;
int
badhits = 0,
ibadline = -1,
numlines = (int)Math.Min(origdata.Length, newdata.Length);
//for each line in our files
for (int i = 0; i < numlines; i++)
{
//for each column of interest
foreach (string col in colnames)
{
//if we don't have a 'match' (comparer.match takes care of the tolerances for us)
if (!comparer.match(origdata[i][orig_lookup[col]], newdata[i][new_lookup[col]], out diff))
{
badhits++;
//if we haven't picked up any fails on this line yet
if (ibadline != i)
{
//if this isn't the first line of our report then make sure we add a newline
if (ibadline >= 0)
{
output.AppendLine();
}
//if it is the first line then make sure we make it clear the file failed
else
{
output.AppendLine("FAIL");
}
//print the line number (remember this is the first fail for this line)
output.AppendFormat("\t{0,-4}:", i);
ibadline = i;
}
//print out the column name of the value that failed, along with the difference
output.AppendFormat("\t{0}:{1}", col, diff);
}
}
}
if (badhits == 0)
{
output.AppendLine("PASS");
}
return(badhits == 0);
}
