| public static ToInt64 ( byte value, int startIndex ) : long | ||
| value | byte | |
| startIndex | int | |
| Результат | long | |
public BTreePage(byte[] pageData)
{
_byteIterator = 0;
Records = new List <NodeRecord> {
Capacity = (int)Static.MemMax
};
Childrens = new List <long> {
Capacity = (int)Static.ChilMax
};
ParentIndex = BC.ToInt64(pageData, _byteIterator);
_byteIterator += sizeof(long);
SelfIndex = BC.ToInt64(pageData, _byteIterator);
_byteIterator += sizeof(long);
_presentRecords = BC.ToInt64(pageData, _byteIterator);
_byteIterator += sizeof(long);
IsLeaf = BC.ToBoolean(pageData, _byteIterator);
_byteIterator += sizeof(bool);
for (var i = 0; i < _presentRecords; i++)
{
var key = BC.ToInt64(pageData, _byteIterator);
_byteIterator += sizeof(long);
var pageIndex = BC.ToInt64(pageData, _byteIterator);
_byteIterator += sizeof(long);
Records.Add(new NodeRecord(key, pageIndex));
}
if (!IsLeaf)
{
for (var i = 0; i < _presentRecords + 1; i++)
{
Childrens.Add(BC.ToInt64(pageData, _byteIterator));
_byteIterator += sizeof(long);
}
}
}
public BTreeHeaderPage(byte[] headerPage)
{
RootIndex = BC.ToInt64(headerPage, _byteIterator);
_byteIterator += sizeof(long);
}
/// <summary>
/// 返回指定的字节数组中以指定位置的字节转换来的值
/// </summary>
/// <param name="buffer">来源字节数组</param>
/// <param name="offset">数据偏移</param>
/// <returns>值</returns>
public static long ToInt64(this byte[] buffer, int offset)
{
return(BitConverter.ToInt64(buffer, offset));
}
public static long ToInt64(ReadOnlySpan <byte> value) => Converter.ToInt64(value);
/// <summary>转为长整数。支持字符串、全角、字节数组（小端）、时间（Unix毫秒）</summary>
/// <param name="value">待转换对象</param>
/// <param name="defaultValue">默认值。待转换对象无效时使用</param>
/// <returns></returns>
public virtual Int64 ToLong(Object value, Int64 defaultValue)
{
if (value == null || value == DBNull.Value)
{
return(defaultValue);
}
// 特殊处理字符串，也是最常见的
if (value is String str)
{
// 拷贝而来的逗号分隔整数
str = str.Replace(",", null);
str = ToDBC(str).Trim();
if (str.IsNullOrEmpty())
{
return(defaultValue);
}
if (Int64.TryParse(str, out var n))
{
return(n);
}
return(defaultValue);
}
// 特殊处理时间，转Unix毫秒
if (value is DateTime dt)
{
if (dt == DateTime.MinValue)
{
return(0);
}
//// 先转UTC时间再相减，以得到绝对时间差
//return (Int32)(dt.ToUniversalTime() - _dt1970).TotalSeconds;
return((Int64)(dt - _dt1970).TotalMilliseconds);
}
if (value is DateTimeOffset dto)
{
if (dto == DateTimeOffset.MinValue)
{
return(0);
}
return((Int64)(dto - _dto1970).TotalMilliseconds);
}
if (value is Byte[] buf)
{
if (buf == null || buf.Length < 1)
{
return(defaultValue);
}
switch (buf.Length)
{
case 1:
return(buf[0]);
case 2:
return(BitConverter.ToInt16(buf, 0));
case 3:
return(BitConverter.ToInt32(new Byte[] { buf[0], buf[1], buf[2], 0 }, 0));
case 4:
return(BitConverter.ToInt32(buf, 0));
case 8:
return(BitConverter.ToInt64(buf, 0));
default:
break;
}
}
//暂时不做处理 先处理异常转换
try
{
return(Convert.ToInt64(value));
}
catch { return(defaultValue); }
}
