private static void CompareContainer(TagContainer c1, TagContainer c2)
{
Assert.AreEqual(c1.Count, c2.Count);
TagDescriptorV3 c1Tag = c1.GetId3V23Descriptor();
TagDescriptorV3 c2Tag = c2.GetId3V23Descriptor();
Assert.AreEqual(c1Tag.MajorVersion, c2Tag.MajorVersion);
Assert.AreEqual(c1Tag.Revision, c2Tag.Revision);
Assert.AreEqual(c1Tag.ExperimentalIndicator, c2Tag.ExperimentalIndicator);
Assert.AreEqual(c1Tag.ExtendedHeader, c2Tag.ExtendedHeader);
Assert.AreEqual(c1Tag.Unsynchronisation, c2Tag.Unsynchronisation);
Assert.AreEqual(c1Tag.CrcDataPresent, c2Tag.CrcDataPresent);
Assert.IsTrue(ComparePayload(c1Tag.Crc, c2Tag.Crc));
Assert.AreEqual(c1Tag.PaddingSize, c2Tag.PaddingSize);
}
private static void EncodeV3(Id3TagInfo tagInfo, TagContainer container)
{
TagDescriptorV3 descriptor = container.GetId3V23Descriptor();
tagInfo.Experimental = descriptor.ExperimentalIndicator;
tagInfo.ExtendedHeaderAvailable = descriptor.ExtendedHeader;
tagInfo.Unsynchronised = descriptor.Unsynchronisation;
if (descriptor.ExtendedHeader)
{
tagInfo.ExtendedHeader = ExtendedTagHeaderV3.Create(descriptor.PaddingSize, descriptor.CrcDataPresent,
descriptor.Crc);
}
}
private static byte[] GetTagHeader(TagContainer tagContainer)
{
var tagHeader = new byte[10];
tagHeader[0] = 0x49;
tagHeader[1] = 0x44;
tagHeader[2] = 0x33;
switch (tagContainer.TagVersion)
{
case TagVersion.Id3V23:
var descriptorV3 = tagContainer.GetId3V23Descriptor();
tagHeader[3] = 0x03;
tagHeader[4] = 0x00;
if (descriptorV3.Unsynchronisation)
{
tagHeader[5] |= 0x80;
}
if (descriptorV3.ExtendedHeader)
{
tagHeader[5] |= 0x40;
}
if (descriptorV3.ExperimentalIndicator)
{
tagHeader[5] |= 0x20;
}
break;
case TagVersion.Id3V24:
var descriptorV4 = tagContainer.GetId3V24Descriptor();
tagHeader[3] = 0x04;
tagHeader[4] = 0x00;
if (descriptorV4.Unsynchronisation)
{
tagHeader[5] |= 0x80;
}
if (descriptorV4.ExtendedHeader)
{
tagHeader[5] |= 0x40;
}
if (descriptorV4.ExperimentalIndicator)
{
tagHeader[5] |= 0x20;
}
if (descriptorV4.Footer)
{
tagHeader[5] |= 0x10;
}
break;
default:
throw new ID3TagException("Unknown version!");
}
return tagHeader;
}
private static byte[] GetExtendedHeaderV3(TagContainer tagContainer)
{
var extendedHeaderBytes = new byte[0];
var tag = tagContainer.GetId3V23Descriptor();
if (tag.ExtendedHeader)
{
var extendedHeaderLength = 0;
if (tag.CrcDataPresent)
{
extendedHeaderLength = 10;
}
else
{
extendedHeaderLength = 6;
}
// Create and set the length
extendedHeaderBytes = new byte[extendedHeaderLength + 4];
extendedHeaderBytes[3] = Convert.ToByte(extendedHeaderLength);
var paddingBytes = BitConverter.GetBytes(tag.PaddingSize);
Array.Reverse(paddingBytes);
Array.Copy(paddingBytes, 0, extendedHeaderBytes, 6, 4);
if (tag.CrcDataPresent)
{
extendedHeaderBytes[4] |= 0x80;
Array.Copy(tag.Crc, 0, extendedHeaderBytes, 10, 4);
}
}
return extendedHeaderBytes;
}
private static byte[] BuildId3V3Tag(TagContainer tagContainer)
{
byte[] tagBytes;
var tag = tagContainer.GetId3V23Descriptor();
var frameBytes = GetFrameBytes(tagContainer);
//
// Calculate the CRC32 value of the frameBytes ( before unsync!)
//
if (tag.CrcDataPresent)
{
var crc32 = new Crc32(Crc32.DefaultPolynom);
var crcValue = crc32.Calculate(frameBytes);
tag.SetCrc32(crcValue);
}
//
// OK. Build the complete tag
//
var extendedHeaderBytes = GetExtendedHeaderV3(tagContainer);
var tagHeader = GetTagHeader(tagContainer);
var rawTagBytes = BuildFinalTag(tagHeader, extendedHeaderBytes, frameBytes, tag.PaddingSize, false);
if (tag.Unsynchronisation)
{
tagBytes = AddUnsyncBytes(rawTagBytes);
}
else
{
tagBytes = rawTagBytes;
}
return tagBytes;
}
