//Private utility functions
#region Private utility functions
/// <summary>
/// Decodes the raw MARC record into a <see cref="MARC.Record"/> at the specified index.///
/// </summary>
/// <param name="index">The index of the record to retrieve.</param>
/// <returns></returns>
private Record decode(int index)
{
string raw = rawSource[index];
Record marc = new Record();
Match match = Regex.Match(raw, "^(\\d{5})");
int recordLength = 0;
int totalExtraBytesRead = 0;
// Store record length
if (match.Captures.Count == 0)
{
marc.AddWarnings("MARC record length is not numeric or incorrect number of characters.");
string[] split = Regex.Split(raw, "[^0-9]");
if (Int32.TryParse(split[0], out recordLength))
{
string padding = "";
padding = padding.PadLeft(5 - split[0].Length, '0');
raw = padding + raw;
}
}
else
{
recordLength = Convert.ToInt32(match.Captures[0].Value);
}
if (recordLength != raw.Length)
{
//Check if there are multi-byte characters in the string
System.Globalization.StringInfo stringInfo = new System.Globalization.StringInfo(raw);
int extraBytes = raw.Length - stringInfo.LengthInTextElements;
int extraBytes2 = Encoding.UTF8.GetByteCount(raw) - raw.Length;
if (recordLength == extraBytes + raw.Length)
{
recordLength -= extraBytes;
}
else if (recordLength == extraBytes2 + raw.Length)
{
recordLength -= extraBytes2;
}
else
{
marc.AddWarnings("MARC record length does not match actual length.");
recordLength = raw.Length;
}
}
if (!raw.EndsWith(END_OF_RECORD.ToString()))
{
throw new InvalidDataException("MARC record ends with an invalid terminator");
}
//Store leader
marc.Leader = raw.Substring(0, LEADER_LEN);
//Bytes 12-16 of leader give offset to the body of the record
int dataStart = Convert.ToInt32(raw.Substring(12, 5));
//Verify data start matches the first end of field marker
if (raw.IndexOf(END_OF_FIELD) + 1 != dataStart)
{
dataStart = raw.IndexOf(END_OF_FIELD) + 1;
marc.AddWarnings("Leader specifies incorrect base address of data.");
}
//Immediately after the leader comes the directory (no separator)
string directory = raw.Substring(LEADER_LEN, dataStart - LEADER_LEN - 1);
//Character after the directory should be END_OF_FIELD
if (raw.Substring(dataStart - 1, 1) != END_OF_FIELD.ToString())
{
marc.AddWarnings("No directory found.");
}
//All directory entries must be DIRECTORY_ENTRY_LEN long, so length % DIRECTORY_ENTRY_LEN should be 0
if (directory.Length % DIRECTORY_ENTRY_LEN != 0)
{
marc.AddWarnings("Invalid directory length.");
}
//Go through all the fields
int fieldCount = directory.Length / DIRECTORY_ENTRY_LEN;
for (int i = 0; i < fieldCount; i++)
{
string tag = directory.Substring(i * DIRECTORY_ENTRY_LEN, DIRECTORY_ENTRY_LEN).Substring(0, 3);
int fieldLength = 0;
int fieldOffset = 0;
try
{
fieldLength = Convert.ToInt32(directory.Substring(i * DIRECTORY_ENTRY_LEN, DIRECTORY_ENTRY_LEN).Substring(3, 4));
}
catch (FormatException)
{
marc.AddWarnings("Invalid Directory Tag Length for tag " + tag + ".");
}
try
{
fieldOffset = Convert.ToInt32(directory.Substring(i * DIRECTORY_ENTRY_LEN, DIRECTORY_ENTRY_LEN).Substring(7, 5)) + totalExtraBytesRead;
}
catch (FormatException)
{
marc.AddWarnings("Invalid Directory Offset for tag " + tag + ".");
}
//Check Directory validity
//If a tag isn't valid, default it to ZZZ. This should at least make the record valid enough to be readable and not throw exceptions
if (!Field.ValidateTag(tag))
{
marc.AddWarnings("Invalid tag " + tag + " in directory.");
tag = "ZZZ";
}
if (fieldOffset + fieldLength > recordLength)
{
marc.AddWarnings("Directory entry for tag " + tag + " runs past the end of the record.");
}
int fieldStart = dataStart + fieldOffset - (totalExtraBytesRead * 2);
if (fieldStart > recordLength)
{
marc.AddWarnings("Directory entry for tag " + tag + " starts past the end of the record. Skipping tag and all proceeding tags.");
break;
}
else if (fieldStart + fieldLength > recordLength)
{
marc.AddWarnings("Directory entry for tag " + tag + " runs past the end of the record.");
fieldLength = recordLength - fieldStart;
}
string tagData = raw.Substring(fieldStart, fieldLength);
//Check if there are multi-byte characters in the string
System.Globalization.StringInfo stringInfo = new System.Globalization.StringInfo(tagData);
int extraBytes = fieldLength - stringInfo.LengthInTextElements;
int extraBytes2 = Encoding.UTF8.GetByteCount(tagData) - fieldLength;
int endOfFieldIndex = tagData.IndexOf(END_OF_FIELD);
if (tagData.Length - 1 != endOfFieldIndex)
{
int differenceLength = tagData.Length - 1 - endOfFieldIndex;
if (differenceLength != extraBytes && differenceLength != extraBytes2)
{
fieldLength -= differenceLength;
totalExtraBytesRead += differenceLength;
tagData = raw.Substring(fieldStart, endOfFieldIndex + 1);
}
else
{
if (extraBytes > 0)
{
fieldLength -= extraBytes;
totalExtraBytesRead += extraBytes;
tagData = raw.Substring(fieldStart, fieldLength);
}
else if (extraBytes2 > 0)
{
fieldLength -= extraBytes2;
totalExtraBytesRead += extraBytes2;
tagData = raw.Substring(fieldStart, fieldLength);
}
}
}
if (fieldLength > 0)
{
string endCharacter = tagData.Substring(tagData.Length - 1, 1);
if (endCharacter == END_OF_FIELD.ToString())
{
//Get rid of the end of tag character
tagData = tagData.Remove(tagData.Length - 1);
fieldLength--;
}
else
{
marc.AddWarnings("Field for tag " + tag + " does not end with an end of field character.");
}
}
else
{
marc.AddWarnings("Field for tag " + tag + " has a length of 0.");
}
match = Regex.Match(tag, "^\\d+$");
if (match.Captures.Count > 0 && Convert.ToInt32(tag) < 10)
{
marc.Fields.Add(new ControlField(tag, tagData));
}
else
{
List <string> rawSubfields = new List <string>(tagData.Split(SUBFIELD_INDICATOR));
string indicators = rawSubfields[0];
rawSubfields.RemoveAt(0);
char ind1;
char ind2;
if (indicators.Length != 2)
{
marc.AddWarnings("Invalid indicator length. Forced indicators to blanks for tag " + tag + ".");
ind1 = ind2 = ' ';
}
else
{
ind1 = char.ToLower(indicators[0]);
if (!DataField.ValidateIndicator(ind1))
{
ind1 = ' ';
marc.AddWarnings("Invalid first indicator. Forced first indicator to blank for tag " + tag + ".");
}
ind2 = char.ToLower(indicators[1]);
if (!DataField.ValidateIndicator(ind2))
{
ind2 = ' ';
marc.AddWarnings("Invalid second indicator. Forced second indicator to blank for tag " + tag + ".");
}
}
//Split the subfield data into subfield name and data pairs
List <Subfield> subfieldData = new List <Subfield>();
foreach (string subfield in rawSubfields)
{
if (subfield.Length > 0)
{
subfieldData.Add(new Subfield(subfield[0], subfield.Substring(1)));
}
else
{
marc.AddWarnings("No subfield data found in tag " + tag + ".");
}
}
if (subfieldData.Count == 0)
{
marc.AddWarnings("No subfield data found in tag " + tag + ".");
}
marc.Fields.Add(new DataField(tag, subfieldData, ind1, ind2));
}
}
return(marc);
}
/// <summary>
/// Decodes the raw MARC record into a <see cref="MARC.Record"/> at the specified index.///
/// </summary>
/// <param name="index">The index of the record to retrieve.</param>
/// <returns></returns>
private Record Decode(int index)
{
string raw = _rawSource[index];
Record marc = new Record();
Match match = Regex.Match(raw, "^(\\d{5})");
int recordLength = 0;
// Store record length
if (match.Captures.Count == 0)
{
marc.AddWarnings("MARC record length is not numeric.");
}
else
{
recordLength = Convert.ToInt32(match.Captures[0].Value);
}
if (recordLength != raw.Length)
{
marc.AddWarnings("MARC record length does not match actual length.");
recordLength = raw.Length;
}
if (!raw.EndsWith(END_OF_RECORD.ToString()))
{
throw new InvalidDataException("MARC record ends with an invalid terminator");
}
//Store leader
marc.Leader = raw.Substring(0, LEADER_LEN);
//Bytes 12-16 of leader give offset to the body of the record
int dataStart = Convert.ToInt32(raw.Substring(12, 5));
//Immediately after the leader comes the directory (no separator)
string directory = raw.Substring(LEADER_LEN, dataStart - LEADER_LEN - 1);
//Character after the directory should be END_OF_FIELD
if (raw.Substring(dataStart - 1, 1) != END_OF_FIELD.ToString())
{
marc.AddWarnings("No directory found.");
}
//All directory entries must be DIRECTORY_ENTRY_LEN long, so length % DIRECTORY_ENTRY_LEN should be 0
if (directory.Length % DIRECTORY_ENTRY_LEN != 0)
{
marc.AddWarnings("Invalid directory length.");
}
//Go through all the fields
int fieldCount = directory.Length / DIRECTORY_ENTRY_LEN;
for (int i = 0; i < fieldCount; i++)
{
string tag = directory.Substring(i * DIRECTORY_ENTRY_LEN, DIRECTORY_ENTRY_LEN).Substring(0, 3);
int fieldLength = 0;
int fieldOffset = 0;
try
{
fieldLength = Convert.ToInt32(directory.Substring(i * DIRECTORY_ENTRY_LEN, DIRECTORY_ENTRY_LEN).Substring(3, 4));
}
catch (FormatException)
{
marc.AddWarnings("Invalid Directory Tag Length for tag " + tag + ".");
}
try
{
fieldOffset = Convert.ToInt32(directory.Substring(i * DIRECTORY_ENTRY_LEN, DIRECTORY_ENTRY_LEN).Substring(7, 5));
}
catch (FormatException)
{
marc.AddWarnings("Invalid Directory Offset for tag " + tag + ".");
}
//Check Directory validity
//If a tag isn't valid, default it to ZZZ. This should at least make the record valid enough to be readable and not throw exceptions
if (!Field.ValidateTag(tag))
{
marc.AddWarnings("Invalid tag " + tag + " in directory.");
tag = "ZZZ";
}
if (fieldOffset + fieldLength > recordLength)
{
marc.AddWarnings("Directory entry for tag " + tag + " runs past the end of the record.");
}
int fieldStart = dataStart + fieldOffset;
if (fieldStart > recordLength)
{
marc.AddWarnings("Directory entry for tag " + tag + " starts past the end of the record. Skipping tag and all proceeding tags.");
break;
}
else if (fieldStart + fieldLength > recordLength)
{
marc.AddWarnings("Directory entry for tag " + tag + " runs past the end of the record.");
fieldLength = recordLength - fieldStart;
}
string tagData = raw.Substring(fieldStart, fieldLength);
if (tagData.Substring(tagData.Length - 1, 1) == END_OF_FIELD.ToString())
{
//Get rid of the end of tag character
tagData = tagData.Remove(tagData.Length - 1);
fieldLength--;
}
else
{
marc.AddWarnings("Field for tag " + tag + " does not end with an end of field character.");
}
match = Regex.Match(tag, "^\\d+$");
if (match.Captures.Count > 0 && Convert.ToInt32(tag) < 10)
{
marc.Fields.Add(new ControlField(tag, tagData));
}
else
{
List <string> rawSubfields = new List <string>(tagData.Split(SUBFIELD_INDICATOR));
string indicators = rawSubfields[0];
rawSubfields.RemoveAt(0);
char ind1;
char ind2;
if (indicators.Length != 2)
{
marc.AddWarnings("Invalid indicator length. Forced indicators to blanks for tag " + tag + ".");
ind1 = ind2 = ' ';
}
else
{
ind1 = char.ToLower(indicators[0]);
if (!DataField.ValidateIndicator(ind1))
{
ind1 = ' ';
marc.AddWarnings("Invalid first indicator. Forced first indicator to blank for tag " + tag + ".");
}
ind2 = char.ToLower(indicators[1]);
if (!DataField.ValidateIndicator(ind2))
{
ind2 = ' ';
marc.AddWarnings("Invalid second indicator. Forced second indicator to blank for tag " + tag + ".");
}
}
//Split the subfield data into subfield name and data pairs
List <Subfield> subfieldData = new List <Subfield>();
foreach (string subfield in rawSubfields)
{
if (subfield.Length > 0)
{
subfieldData.Add(new Subfield(subfield[0], subfield.Substring(1)));
}
else
{
marc.AddWarnings("No subfield data found in tag " + tag + ".");
}
}
if (subfieldData.Count == 0)
{
marc.AddWarnings("No subfield data found in tag " + tag + ".");
}
marc.Fields.Add(new DataField(tag, subfieldData, ind1, ind2));
}
}
return(marc);
}
