public static Mp3XingBlock.Model Create(byte[] buf, Mp3Header header)
{
System.Diagnostics.Debug.Assert(header.IsMpegLayer3);
int xix = header.XingOffset;
string xingString = ConvertTo.FromAsciiToString(buf, xix, 4);
if (xingString == "Info" || xingString == "Xing")
{
string lameString = ConvertTo.FromAsciiToString(buf, xix + 0x78, 9);
if (lameString.StartsWith("LAME"))
{
return(new Mp3LameBlock.Model(buf, xix, header, xingString, lameString));
}
else
{
return(new Mp3XingBlock.Model(buf, xix, header, xingString));
}
}
return(null);
}
private void ParseAif(Stream stream, byte[] hdr)
{
Data.GroupId = ConvertTo.FromAsciiToString(hdr, 0, 4);
Data.FormType = ConvertTo.FromAsciiToString(hdr, 8, 4);
UInt32 gSize = ConvertTo.FromBig32ToUInt32(hdr, 4);
if (gSize < 12 || gSize > stream.Length - 8)
{
IssueModel.Add("File truncated or corrupt.", Severity.Fatal); return;
}
int hPos = 12;
string id0 = ConvertTo.FromAsciiToString(hdr, 12, 4);
if (Data.IsCompressed)
{
if (id0 != "FVER")
{
IssueModel.Add("Missing 'FVER' chunk."); return;
}
UInt32 vSize = ConvertTo.FromBig32ToUInt32(hdr, 16);
if (vSize != 4)
{
IssueModel.Add("Bad 'FVER' chunk."); return;
}
hPos = 24;
id0 = ConvertTo.FromAsciiToString(hdr, 24, 4);
}
if (id0 != "COMM")
{
IssueModel.Add("Missing 'COMM' chunk."); return;
}
UInt32 cSize = ConvertTo.FromBig32ToUInt32(hdr, hPos + 4);
if (cSize < 18 || cSize > stream.Length - 8)
{
IssueModel.Add("Bad 'COMM' chunk."); return;
}
Data.ChannelCount = ConvertTo.FromBig16ToInt32(hdr, hPos + 8);
Data.SampleSize = ConvertTo.FromBig16ToInt32(hdr, hPos + 14);
++Data.IffChunkCount;
Data.IffSize = gSize;
Data.mediaPosition = 0;
Data.MediaCount = gSize + 8;
Data.ValidSize = hPos + cSize + 8;
var hasSSND = false;
var buf = new byte[8];
while (Data.ValidSize < Data.MediaCount)
{
stream.Position = Data.ValidSize;
int got = stream.Read(buf, 0, 8);
if (got != 8)
{
IssueModel.Add("Read failed."); return;
}
cSize = ConvertTo.FromBig32ToUInt32(buf, 4);
if (cSize < 8 || Data.ValidSize + cSize > Data.MediaCount - 8)
{
IssueModel.Add("Bad chunk size or truncated file."); return;
}
string id = ConvertTo.FromAsciiToString(buf, 0, 4);
if (id == "SSND")
{
if (hasSSND)
{
IssueModel.Add("Many 'SSND' chunks."); return;
}
hasSSND = true;
}
else if (id != "(c) " && id != "ANNO" && id != "AUTH" && id != "NAME")
{
IssueModel.Add($"Unexpected '{id}' chunk.", Severity.Trivia, IssueTags.StrictWarn); return;
}
Data.ValidSize += cSize + 8;
if ((cSize & 1) != 0)
{
++Data.ValidSize;
}
}
if (!hasSSND)
{
IssueModel.Add("Missing 'SSND' chunk.", Severity.Warning);
}
}