/************************
* public static methods
*/
public static TTCHeader ReadTTCHeader(OTFile file)
{
TTCHeader ttc = null;
const int SIZEOF_FIRSTTHREEFIELDS = 12;
const int SIZEOF_UINT = 4;
// read the first three fields of the TTC Header
// starting at the beginning of the file
MBOBuffer buf = file.ReadPaddedBuffer(0, SIZEOF_FIRSTTHREEFIELDS);
OTTag tag = null;
uint version = 0;
uint DirectoryCount = 0;
if (buf != null)
{
tag = new OTTag(buf.GetBuffer());
version = buf.GetUint(4);
DirectoryCount = buf.GetUint(8);
}
// if the tag and the version and the dir count seem correct then
// allocate a TTCHeader object and try to read the rest of the header
if ((string)tag == "ttcf" &&
(version == 0x00010000 || version == 0x00020000) &&
12 + DirectoryCount * SIZEOF_UINT < file.GetFileLength())
{
ttc = new TTCHeader();
ttc.TTCTag = tag;
ttc.version = version;
ttc.DirectoryCount = DirectoryCount;
// Directory offsets
buf = file.ReadPaddedBuffer(SIZEOF_FIRSTTHREEFIELDS, DirectoryCount*SIZEOF_UINT);
if (buf != null)
{
for (uint i=0; i<ttc.DirectoryCount; i++)
{
uint offset = buf.GetUint(i*SIZEOF_UINT);
ttc.DirectoryOffsets.Add(offset);
}
}
// only read Dsig fields if version 2.0 and last buffer was successfully read
if ((version == 0x00010000 || version == 0x00020000) && buf != null)
{
uint filepos = SIZEOF_FIRSTTHREEFIELDS + DirectoryCount*SIZEOF_UINT;
buf = file.ReadPaddedBuffer(filepos, 3*SIZEOF_UINT);
if (buf != null)
{
// DsigTag
ttc.DsigTag = new OTTag(buf.GetBuffer());
if ( ( version == 0x00010000 ) && ( (string) ttc.DsigTag != "DSIG" ) )
{
// failed v1 trial - reset & bail
ttc.DsigTag = null;
return ttc;
}
// DsigLength
ttc.DsigLength = buf.GetUint(4);
// DsigOffset
ttc.DsigOffset = buf.GetUint(8);
}
}
}
return ttc;
}
/************************
* public static methods
*/
public static TTCHeader ReadTTCHeader(OTFile file)
{
TTCHeader ttc = null;
const int SIZEOF_FIRSTTHREEFIELDS = 12;
const int SIZEOF_UINT = 4;
// read the first three fields of the TTC Header
// starting at the beginning of the file
MBOBuffer buf = file.ReadPaddedBuffer(0, SIZEOF_FIRSTTHREEFIELDS);
OTTag tag = null;
uint version = 0;
uint DirectoryCount = 0;
if (buf != null)
{
tag = new OTTag(buf.GetBuffer());
version = buf.GetUint(4);
DirectoryCount = buf.GetUint(8);
}
// if the tag and the version and the dir count seem correct then
// allocate a TTCHeader object and try to read the rest of the header
if ((string)tag == "ttcf" &&
(version == 0x00010000 || version == 0x00020000) &&
12 + DirectoryCount * SIZEOF_UINT < file.GetFileLength())
{
ttc = new TTCHeader();
ttc.TTCTag = tag;
ttc.version = version;
ttc.DirectoryCount = DirectoryCount;
// Directory offsets
buf = file.ReadPaddedBuffer(SIZEOF_FIRSTTHREEFIELDS, DirectoryCount * SIZEOF_UINT);
if (buf != null)
{
for (uint i = 0; i < ttc.DirectoryCount; i++)
{
uint offset = buf.GetUint(i * SIZEOF_UINT);
ttc.DirectoryOffsets.Add(offset);
}
}
// only read Dsig fields if version 2.0 and last buffer was successfully read
if ((version == 0x00010000 || version == 0x00020000) && buf != null)
{
uint filepos = SIZEOF_FIRSTTHREEFIELDS + DirectoryCount * SIZEOF_UINT;
buf = file.ReadPaddedBuffer(filepos, 3 * SIZEOF_UINT);
if (buf != null)
{
// DsigTag
ttc.DsigTag = new OTTag(buf.GetBuffer());
if ((version == 0x00010000) && ((string)ttc.DsigTag != "DSIG"))
{
// failed v1 trial - reset & bail
ttc.DsigTag = null;
return(ttc);
}
// DsigLength
ttc.DsigLength = buf.GetUint(4);
// DsigOffset
ttc.DsigOffset = buf.GetUint(8);
}
}
}
return(ttc);
}