private static VariableRecord GetVlsExtraVariable(VariableRecord variable, Encoding encoding, int segmentLength, SortedSet <byte[]> previousVariableNames, SortedList <byte[], int> segmentsNamesList, byte[] originalName)
{
var outputFormat = new OutputFormat(FormatType.A, segmentLength);
var record = new VariableRecord
{
Encoding = encoding,
_nameRaw = GenerateContinuationSegmentShortName(originalName, previousVariableNames, segmentsNamesList),
Label = variable.Label,
Type = segmentLength,
PrintFormat = outputFormat,
WriteFormat = outputFormat,
DisplayInfo = variable.DisplayInfo
};
return(record);
}
/// <summary>
/// Checks if the name that was set (after slicing it to 8 chars and encoding it properly) is not repeated on the names
/// of the variables created before this one.
/// </summary>
/// <param name="variable"></param>
/// <param name="previousVariableNames"></param>
/// <param name="longNameCounter"></param>
private static void CheckShortName(VariableRecord variable, SortedSet <byte[]> previousVariableNames, ref int longNameCounter)
{
// Check if it's already on the variable records names (compare with raw encoded name byte array)
if (previousVariableNames.Contains(variable._nameRaw))
{
// Algorithm to create a variable with a short name.
// As produced by "IBM SPSS STATISTICS 64-bit MS Windows 22.0.0.0"
var currentLongNameIndex = ++longNameCounter;
// Avoid collisions in case there is already a var called VXX_A
var appendCharIndex = 0;
do
{
variable.Name = $"V{currentLongNameIndex}_{AppendableChars[appendCharIndex++]}";
} while (previousVariableNames.Contains(variable._nameRaw));
}
// Add the raw encoded name byte array to avoid collitions in following variables
previousVariableNames.Add(variable._nameRaw);
}
/// <summary>
/// Creates all variable records needed for this variable
/// </summary>
/// <param name="variable">The variable matadata to create the new variable</param>
/// <param name="headerEncoding">The encoding to use on the header</param>
/// <param name="previousVariableNames">
/// A list of the variable names that were already
/// created, to avoid the short name colition
/// </param>
/// <param name="longNameCounter">
/// The counter of variables with name replaced, to create
/// a proper long name that won't collide
/// </param>
/// <param name="longStringVariables"></param>
/// <param name="segmentsNamesList"></param>
/// <returns>
/// Only one var for numbers or text of lenght 8 or less, or the
/// main variable definition, followed by string continuation "dummy"
/// variables. There should be one for each 8 chars after the first 8.
/// </returns>
internal static VariableRecord[] GetNeededVariables(Variable variable, Encoding headerEncoding, SortedSet <byte[]> previousVariableNames, ref int longNameCounter, IDictionary <string, int> longStringVariables, SortedList <byte[], int> segmentsNamesList)
{
var header = new VariableRecord(variable, headerEncoding)
{
DisplayInfo = GetVariableDisplayInfo(variable)
};
var originalName = header._nameRaw;
CheckShortName(header, previousVariableNames, ref longNameCounter);
// Set output format for text variables to be equal to textwidth
// Also detect if a variable is extra wide and needs to be cut up over multiple variables (long string variables)
if (variable.Type == DataType.Text)
{
if (variable.TextWidth <= 255)
{
header.WriteFormat = new OutputFormat(FormatType.A, variable.TextWidth);
header.PrintFormat = new OutputFormat(FormatType.A, variable.TextWidth);
}
else
{
longStringVariables.Add(header.Name, variable.TextWidth);
header.WriteFormat = new OutputFormat(FormatType.A, 255);
header.PrintFormat = new OutputFormat(FormatType.A, 255);
}
}
// If it's numeric or a string of lenght 8 or less, no dummy vars are needed
if (variable.Type == DataType.Numeric || variable.TextWidth <= 8)
{
return(new [] { header });
}
var segments = GetLongStringSegmentsCount(variable.TextWidth);
if (!(segments > 0))
{
throw new SpssFileFormatException("String variables can no have less than one segment");
}
// Create all the variable continuation records that for each extra 8 bytes of string data
// The actual count of needed VariableRecords
var varCount = GetLongStringContinuationRecordsCount(variable.TextWidth);
var result = new VariableRecord[varCount];
var dummyVar = GetStringContinuationRecord();
var fullSegmentBlocks = GetStringContinuationRecordsCount(255);
var segmentLength = segments > 1 ? 255 : GetFinalSegmentLenght(variable.TextWidth, segments);
var segmentBlocks = GetStringContinuationRecordsCount(segmentLength);
header.Type = segmentLength;
result[0] = header;
var currentSegment = 0;
var i = 1;
while (true)
{
var segmentBaseIndex = fullSegmentBlocks * currentSegment;
for (; i < segmentBaseIndex + segmentBlocks; i++)
{
result[i] = dummyVar;
}
currentSegment++;
var segmentsLeft = segments - currentSegment;
if (segmentsLeft <= 0)
{
break;
}
segmentLength = segmentsLeft > 1 ? 255 : GetFinalSegmentLenght(variable.TextWidth, segments);
segmentBlocks = GetStringContinuationRecordsCount(segmentLength);
result[i++] = GetVlsExtraVariable(header, headerEncoding, segmentLength, previousVariableNames, segmentsNamesList, originalName);
}
return(result);
}