public ReadContext ReadHeader(IFormattedReader r)
{
var rc = new ReadContext(r);
try
{
var bom = r.ReadInt64();
if (bom != 0x0d0e0a0402080500) throw new FileFormatException("Expected Signature not found. Either this file is not a TeaFile or the byte order (endianness) differs between the machine were the file was written and the local machine. Expected:'{0:x}'\nFound: '{1:x}'\n".Formatted(0x0d0e0a0402080500, bom));
rc.ItemAreaStart = r.ReadInt64();
rc.ItemAreaEnd = r.ReadInt64();
rc.SectionCount = r.ReadInt64();
for (int i = 0; i < rc.SectionCount; i++)
{
int sectionId = r.ReadInt32();
int nextSectionOffset = r.ReadInt32();
int nextSectionStart = (int)r.Position + nextSectionOffset;
if (nextSectionStart > rc.ItemAreaStart) throw new FileFormatException("NextSectionOffset of section number {0} is wrong: Next Section Start would be beyond ItemStart.".Formatted(i));
ISectionFormatter sectionFormatter = this.sectionFormatters.FirstOrDefault(f => f.Id == sectionId);
if (sectionFormatter != null)
{
sectionFormatter.Read(rc);
if (r.Position > nextSectionStart) throw new FileFormatException("Section read too many bytes from the stream. SectionId:{0} SectionName:{1}".Formatted(sectionId, sectionFormatter.GetType().Name.Replace("Formatter", "")));
}
int bytesToSkip = nextSectionStart - (int)r.Position;
if (bytesToSkip < 0) throw new FileFormatException("Reading sections from the file header failed. Section with id {0} reads more bytes than reserved for that section".Formatted(sectionId));
r.SkipBytes(bytesToSkip);
}
if (r.Position > rc.ItemAreaStart) throw new FileFormatException("Stream position is behind start of item area.");
r.SkipBytes((int)rc.ItemAreaStart - (int)r.Position);
if (rc.ItemAreaStart != r.Position) throw new FileFormatException("Stream Position could not be set to start of item area.");
return rc;
}
catch (FileFormatException)
{
throw;
}
catch (Exception ex)
{
// communicate any unexpected Header Read Error (e.g. an error while reading from disc)
throw new FileFormatException("Error reading TeaFile Header: {0}".Formatted(ex.Message), ex);
}
}
public ReadContext(IFormattedReader reader)
{
this.Description = new TeaFileDescription();
this.Reader = reader;
}
public ReadContext(IFormattedReader reader)
{
this.Description = new TeaFileDescription();
this.Reader = reader;
}
public ReadContext ReadHeader(IFormattedReader r)
{
var rc = new ReadContext(r);
try
{
var bom = r.ReadInt64();
if (bom != 0x0d0e0a0402080500)
{
throw new FileFormatException("Expected Signature not found. Either this file is not a TeaFile or the byte order (endianness) differs between the machine were the file was written and the local machine. Expected:'{0:x}'\nFound: '{1:x}'\n".Formatted(0x0d0e0a0402080500, bom));
}
rc.ItemAreaStart = r.ReadInt64();
rc.ItemAreaEnd = r.ReadInt64();
rc.SectionCount = r.ReadInt64();
for (int i = 0; i < rc.SectionCount; i++)
{
int sectionId = r.ReadInt32();
int nextSectionOffset = r.ReadInt32();
int nextSectionStart = (int)r.Position + nextSectionOffset;
if (nextSectionStart > rc.ItemAreaStart)
{
throw new FileFormatException("NextSectionOffset of section number {0} is wrong: Next Section Start would be beyond ItemStart.".Formatted(i));
}
ISectionFormatter sectionFormatter = this.sectionFormatters.FirstOrDefault(f => f.Id == sectionId);
if (sectionFormatter != null)
{
sectionFormatter.Read(rc);
if (r.Position > nextSectionStart)
{
throw new FileFormatException("Section read too many bytes from the stream. SectionId:{0} SectionName:{1}".Formatted(sectionId, sectionFormatter.GetType().Name.Replace("Formatter", "")));
}
}
int bytesToSkip = nextSectionStart - (int)r.Position;
if (bytesToSkip < 0)
{
throw new FileFormatException("Reading sections from the file header failed. Section with id {0} reads more bytes than reserved for that section".Formatted(sectionId));
}
r.SkipBytes(bytesToSkip);
}
if (r.Position > rc.ItemAreaStart)
{
throw new FileFormatException("Stream position is behind start of item area.");
}
r.SkipBytes((int)rc.ItemAreaStart - (int)r.Position);
if (rc.ItemAreaStart != r.Position)
{
throw new FileFormatException("Stream Position could not be set to start of item area.");
}
return(rc);
}
catch (FileFormatException)
{
throw;
}
catch (Exception ex)
{
// communicate any unexpected Header Read Error (e.g. an error while reading from disc)
throw new FileFormatException("Error reading TeaFile Header: {0}".Formatted(ex.Message), ex);
}
}
