public DbaseFileHeader(DateTime lastUpdated, DbaseCodePage codePage, DbaseRecordCount recordCount,
DbaseSchema schema)
{
LastUpdated = lastUpdated.RoundToDay();
CodePage = codePage;
RecordCount = recordCount;
Schema = schema;
}
public void ParseValueMustBeSupported()
{
var allSupported = Array.ConvertAll(DbaseCodePage.All, _ => _.ToByte());
var value = new Generator <byte>(_fixture)
.First(candidate => !Array.Exists(allSupported, supported => supported == candidate));
Assert.Throws <ArgumentException>(() => DbaseCodePage.Parse(value));
}
public void ToStringReturnsExpectedValue()
{
var value = _fixture.Create <byte>().AsDbaseCodePageValue();
var sut = DbaseCodePage.Parse(value);
var result = sut.ToString();
Assert.Equal(value.ToString(), result);
}
public void TryParseWithSupportedValueReturnsExpectedResult()
{
var supported = _fixture.Create <DbaseCodePage>();
var result = DbaseCodePage.TryParse(supported.ToByte(), out DbaseCodePage parsed);
Assert.True(result);
Assert.Equal(supported, parsed);
}
public void TryParseWithUnsupportedValueReturnsExpectedResult()
{
var allSupported = Array.ConvertAll(DbaseCodePage.All, _ => _.ToByte());
var value = new Generator <byte>(_fixture)
.First(candidate => !Array.Exists(allSupported, supported => supported == candidate));
var result = DbaseCodePage.TryParse(value, out DbaseCodePage parsed);
Assert.False(result);
Assert.Null(parsed);
}
public static DbaseFileHeader Read(BinaryReader reader)
{
if (reader == null)
{
throw new ArgumentNullException(nameof(reader));
}
if (reader.ReadByte() != ExpectedDbaseFormat)
{
throw new DbaseFileHeaderException("The database file type must be 3 (dBase III).");
}
var lastUpdated = new DateTime(reader.ReadByte() + 1900, reader.ReadByte(), reader.ReadByte(), 0, 0, 0,
DateTimeKind.Unspecified);
var recordCount = new DbaseRecordCount(reader.ReadInt32());
var headerLength = reader.ReadInt16();
var fieldCount = (headerLength - HeaderMetaDataSize) / FieldMetaDataSize;
if (fieldCount > DbaseSchema.MaximumFieldCount)
{
throw new DbaseFileHeaderException(
$"The database file can not contain more than {DbaseSchema.MaximumFieldCount} fields.");
}
var recordLength = new DbaseRecordLength(reader.ReadInt16());
reader.ReadBytes(17);
var rawCodePage = reader.ReadByte();
if (!DbaseCodePage.TryParse(rawCodePage, out var codePage))
{
throw new DbaseFileHeaderException($"The database code page {rawCodePage} is not supported.");
}
reader.ReadBytes(2);
var fields = new DbaseField[fieldCount];
for (var recordFieldIndex = 0; recordFieldIndex < fieldCount; recordFieldIndex++)
{
fields[recordFieldIndex] = DbaseField.Read(reader);
}
// verify field offsets are aligned
var offset = ByteOffset.Initial;
foreach (var field in fields)
{
if (field.Offset != offset)
{
throw new DbaseFileHeaderException(
$"The field {field.Name} does not have the expected offset {offset} but instead {field.Offset}. Please ensure the offset has been properly set for each field and that the order in which they appear in the record field layout matches their offset.");
}
offset = field.Offset.Plus(field.Length);
}
var schema = new AnonymousDbaseSchema(fields);
if (recordLength != schema.Length)
{
throw new DbaseFileHeaderException(
$"The database file record length ({recordLength}) does not match the total length of all fields ({schema.Length}).");
}
if (reader.ReadByte() != Terminator)
{
throw new DbaseFileHeaderException("The database file header terminator is missing.");
}
// skip to first record
var bytesToSkip = headerLength - (HeaderMetaDataSize + FieldMetaDataSize * fieldCount);
reader.ReadBytes(bytesToSkip);
return(new DbaseFileHeader(lastUpdated, codePage, recordCount, schema));
}
