/// <summary>
/// 从流中读取文件头
/// </summary>
/// <param name="stream"></param>
/// <returns></returns>
public static AbHeader From(Stream stream)
{
var header = new AbHeader();
if (stream == null)
{
return(null);
}
// 魔术字 ==> 1
header.Magic = ReadLine(stream);
if (!string.Equals(header.Magic, HEADER_MAGIC))
{
return(null);
}
// 备份文件版本 ==> 2
header.Version = ReadInt(stream);
if (header.Version == -1)
{
return(null);
}
// 是否经过压缩 ==> 3
header.Compressed = ReadInt(stream) == 1;
// 加密算法 ==> 4
header.Algorithm = ReadLine(stream);
if (string.Equals(header.Algorithm, ENCRYPTION_ALGORITHM))
{
header.IsEncrypted = true;
}
// 如果未加密，文件头解析结束
if (!header.IsEncrypted)
{
header.Valid = true;
return(header);
}
// 用户盐 ==> 5
header.UserSalt = ReadBytes(stream);
if (header.UserSalt.Length != PBKDF2_SALT_SIZE / 8)
{
header.Valid = false;
return(null);
}
// 用户盐校验和 ==> 6
header.SaltCheckSum = ReadBytes(stream);
// 循环数 ==> 7
header.Rounds = ReadInt(stream);
// 用户向量 ==> 8
header.UserIv = ReadBytes(stream);
// 主密钥 ==> 9
header.MasterKey = ReadBytes(stream);
// Header读取成功
header.Valid = true;
return(header);
}
/// <summary>
/// 读取备份文件，获取实例
/// </summary>
/// <param name="path"></param>
/// <param name="handler"></param>
/// <returns></returns>
public static AbFile With(string path, Func <bool, PasswdResult> handler)
{
var file = new AbFile
{
PasswdHandler = handler
};
try
{
// 读取备份文件流
file.Stream = File.OpenRead(path);
}
catch (Exception exception)
{
// 记录日志
Logger.Error(exception);
return(null);
}
file.header = AbHeader.From(file.Stream);
return(file);
}
