public IEnumerable <(long index, long size)> Search(Stream stream, ICustomSignSearchSetting setting, IProgressReporter reporter)
{
if (setting == null)
{
throw new ArgumentNullException(nameof(setting));
}
if (stream == null)
{
throw new ArgumentNullException(nameof(stream));
}
if (setting.AlignToSec)
{
return(SearchWithAlignment(stream, setting, reporter));
}
else
{
return(SearchWithoutAlignment(stream, setting, reporter));
}
}
public static IEnumerable <(long index, long size)> Search(Stream stream, ICustomSignSearchSetting setting, IProgressReporter reporter) => Current?.Search(stream, setting, reporter);
/// <summary>
/// 通过对齐的方式搜索;
/// </summary>
/// <param name="stream"></param>
/// <param name="setting"></param>
/// <param name="reporter"></param>
/// <returns></returns>
private IEnumerable <(long index, long size)> SearchWithAlignment(Stream stream, ICustomSignSearchSetting setting, IProgressReporter reporter)
{
var len = stream.Length;
stream.Position = setting.SecStartLBA * setting.SectorSize;
var loc = stream.Position;
var buffer = new byte[4096 * setting.SectorSize];
long lastPosition = -1;
var keyWord = setting.KeyWord;
while (loc < len)
{
var readLen = stream.Read(buffer, 0, buffer.Length);
var readTime = readLen / setting.SectorSize;
var readIndex = 0;
while (readIndex < readTime)
{
if (ByteExtensions.IsHeadSame(buffer,
keyWord, keyWord.Length,
readIndex * setting.SectorSize + setting.SecStartLBA))
{
if (lastPosition != -1)
{
yield return(lastPosition, readIndex *setting.SectorSize + loc - lastPosition);
}
lastPosition = readIndex * setting.SectorSize + loc;
}
readIndex++;
}
loc += readLen;
if (loc % 104857600 == 0)
{
reporter?.ReportProgress((int)(loc * 100 / stream.Length));
}
if (reporter?.CancelPending ?? false)
{
break;
}
}
}
/// <summary>
/// 不通过对齐的方式搜索;
/// </summary>
/// <param name="stream"></param>
/// <param name="setting"></param>
/// <param name="reporter"></param>
/// <returns></returns>
private IEnumerable <(long index, long size)> SearchWithoutAlignment(Stream stream, ICustomSignSearchSetting setting, IProgressReporter reporter)
{
stream.Position = setting.SecStartLBA * setting.SectorSize;
var pinLen = setting.KeyWord.Length; //获得标识长度;
var readLen = 0;
var keyWord = setting.KeyWord;
var bufferLen = 1024 * 1024 * 4 + pinLen - 1; //缓冲区大小为预缓冲区大小+(pinLen - 1);
var buffer = new byte[bufferLen];
long lastPosition = -1;
long curOffset = 0;
//将前pinLen - 1位 置为与Ke不等的数字,确保第一次循环时前几位不会影响结果;
for (var i = 0; i < pinLen - 1; i++)
{
//对于pin[i],遍历所有字节,找到不满足的;
for (byte j = 0; j < 0xff; j++)
{
//是否找到相等的结果;
if (!keyWord.Any(p => p == j))
{
buffer[i] = j;
break;
}
}
}
while ((readLen = stream.Read(buffer, pinLen - 1, bufferLen - pinLen + 1)) != 0)
{
//轮询缓冲区pin剩余长度以后的内容;
for (var i = 0; i < readLen; i++)
{
if (buffer[i] != keyWord[0])
{
continue;
}
if (ByteExtensions.IsHeadSame(buffer, keyWord, pinLen - 1, i + 1, 1))
{
if (lastPosition != -1)
{
yield return(lastPosition, curOffset + i - pinLen + 1 - lastPosition);
}
lastPosition = curOffset + i - pinLen + 1;
i += pinLen;
}
}
//后面未检索的几位向前推移至缓冲区首;
Buffer.BlockCopy(buffer, readLen, buffer, 0, pinLen - 1);
curOffset += readLen;
reporter?.ReportProgress((int)(curOffset * 100 / stream.Length));
if (reporter?.CancelPending ?? false)
{
break;
}
}
}
