/// <summary>
/// 根据代码节点生成IL代码
/// </summary>
/// <param name="rootNode">代码根节点</param>
/// <param name="length">字符串长度</param>
/// <param name="columnLength">第几列</param>
/// <returns></returns>
public FindDelegate Generate(FastFindSameLengthStringHelper.Node rootNode, int length, int columnLength)
{
var typeBuilder = NFinal.Emit.UnSafeHelper.GetDynamicType();
MethodBuilder dynamicMethod = typeBuilder.DefineMethod("Compare", MethodAttributes.Public
| MethodAttributes.Static | MethodAttributes.HideBySig, CallingConventions.Standard,
typeof(int), new Type[] { typeof(char *) });
ILGenerator iLGenerator = dynamicMethod.GetILGenerator();
WriteCode(iLGenerator, ref rootNode, length, columnLength);
return(NFinal.Emit.UnSafeHelper.GetDelegate <FindDelegate>(typeBuilder, "Compare"));
}
/// <summary>
/// 利用IL书写查找函数
/// </summary>
/// <param name="iLGenerator">IL发生器</param>
/// <param name="codeNode">代码节点</param>
/// <param name="length">字符串长度</param>
/// <param name="columnLength">列长度</param>
public void WriteCode(ILGenerator iLGenerator, ref FastFindSameLengthStringHelper.Node codeNode, int length, int columnLength)
{
if (codeNode.nodeType == FastFindSameLengthStringHelper.NodeType.CompareCreaterThan ||
codeNode.nodeType == FastFindSameLengthStringHelper.NodeType.CompareLessThan)
{
var elseCase = iLGenerator.DefineLabel();
var endIfCase = iLGenerator.DefineLabel();
iLGenerator.Emit(OpCodes.Ldarg_0);
if (codeNode.charIndex == columnLength - 1)
{
int remain = length & 3;
WriteCompare(iLGenerator, ref codeNode, remain);
}
else
{
if (codeNode.charIndex > 0)
{
iLGenerator.Emit(OpCodes.Ldc_I4, codeNode.charIndex * 2);
iLGenerator.Emit(OpCodes.Add);
}
iLGenerator.Emit(OpCodes.Ldind_I8);
iLGenerator.Emit(OpCodes.Ldc_I8, codeNode.compareValue);
}
if (codeNode.nodeType == FastFindSameLengthStringHelper.NodeType.CompareCreaterThan)
{
iLGenerator.Emit(OpCodes.Ble, elseCase);
}
if (codeNode.nodeType == FastFindSameLengthStringHelper.NodeType.CompareLessThan)
{
iLGenerator.Emit(OpCodes.Bge, elseCase);
}
#region If
if (codeNode.ifCase != null)
{
WriteCode(iLGenerator, ref codeNode.ifCase, length, columnLength);
}
#endregion
iLGenerator.MarkLabel(elseCase);
#region Else
if (codeNode.elseCase != null)
{
WriteCode(iLGenerator, ref codeNode.elseCase, length, columnLength);
}
#endregion
iLGenerator.MarkLabel(endIfCase);
}
else
{
iLGenerator.Emit(OpCodes.Ldc_I4, codeNode.arrayIndex);
iLGenerator.Emit(OpCodes.Ret);
}
}
/// <summary>
/// 利用IL书写比较函数
/// </summary>
/// <param name="iLGenerator">IL代码发生器</param>
/// <param name="codeNode">代码节点</param>
/// <param name="remain">剩余长度</param>
public void WriteCompare(ILGenerator iLGenerator, ref FastFindSameLengthStringHelper.Node codeNode, int remain)
{
if (remain == 0)
{
if (codeNode.charIndex > 0)
{
iLGenerator.Emit(OpCodes.Ldc_I4, codeNode.charIndex * 2);
iLGenerator.Emit(OpCodes.Add);
}
iLGenerator.Emit(OpCodes.Ldind_I8);
iLGenerator.Emit(OpCodes.Ldc_I8, codeNode.compareValue);
}
else if (remain == 1)
{
if (codeNode.charIndex > 0)
{
iLGenerator.Emit(OpCodes.Ldc_I4, codeNode.charIndex * 2);
iLGenerator.Emit(OpCodes.Add);
}
iLGenerator.Emit(OpCodes.Ldind_I2);//不需要转换short和int字节数相同
//iLGenerator.Emit(OpCodes.Conv_I4);
iLGenerator.Emit(OpCodes.Ldc_I4, (short)codeNode.compareValue);
}
else if (remain == 2)
{
if (codeNode.charIndex > 0)
{
iLGenerator.Emit(OpCodes.Ldc_I4, codeNode.charIndex * 2);
iLGenerator.Emit(OpCodes.Add);
}
iLGenerator.Emit(OpCodes.Ldind_I4);
iLGenerator.Emit(OpCodes.Ldc_I4, (int)codeNode.compareValue);
}
else if (remain == 3)
{
if (codeNode.charIndex > 0)
{
iLGenerator.Emit(OpCodes.Ldc_I4, codeNode.charIndex * 2 - 1);
iLGenerator.Emit(OpCodes.Add);
}
iLGenerator.Emit(OpCodes.Ldind_I8);
iLGenerator.Emit(OpCodes.Ldc_I8, codeNode.compareValue);
}
}
