private byte[] Unpack(YlFilePackage pack)
{
MemoryStream ms = new MemoryStream();
BinaryWriter bw = new BinaryWriter(ms);
#region write head info
//write file count
short count = (short)pack.Files.Count;
bw.Write(count);
foreach (YlFileInfo info in pack.Files)
{
bw.Write(info.FileNameIndex); //4字节：图片文件名起始位置
bw.Write((short)StringToUnicodeBytes(info.File.FileName).Length); //2字节：文件名长度
bw.Write(info.FileContentIndex); //4字节：图片内容起始位置
bw.Write(info.File.FileLength); //4字节：图片文件长度
}
#endregion
#region write content
foreach (YlFileInfo info in pack.Files)
{
bw.Write(StringToUnicodeBytes(info.File.FileName));
bw.Write(info.File.Content);
}
#endregion
bw.Flush();
bw.Close();
ms.Close();
return ms.ToArray();
}
private YlFilePackage Pack(List<YlFile> files, List<string> fileIds)
{
YlFilePackage pkg = new YlFilePackage();
//create head info
int fileCount = files.Count;
int pos = 0;
int headLength = 0;
pkg.Files = new List<YlFileInfo>();
foreach (YlFile file in files)
{
YlFileInfo info = new YlFileInfo();
info.File = file;
//4字节：图片文件名起始位置
//2字节：文件名长度
//4字节：图片内容起始位置
//4字节：图片文件长度
headLength += 4 * 3 + 2;
pkg.Files.Add(info);
}
pos += 2 + headLength; //文件数长度 + 头长度
pkg.HeadLength = pos;
//update filename index
foreach (YlFileInfo info in pkg.Files)
{
info.FileNameIndex = pos;
byte[] fnBytes = StringToUnicodeBytes(info.File.FileName);
info.FileNameIndex = pos;
pos += fnBytes.Length;
info.FileContentIndex = pos;
pos += info.File.FileLength;
}
pkg.FileLength = pos;
return pkg;
}