internal string DescribeInstruction(int opcodeOffset)
{
RegexOpcode opcode = (RegexOpcode)Codes[opcodeOffset];
var sb = new StringBuilder();
sb.Append($"{opcodeOffset:D6} ");
sb.Append(OpcodeBacktracks(opcode & RegexOpcode.OperatorMask) ? '~' : ' ');
sb.Append(opcode & RegexOpcode.OperatorMask);
if ((opcode & RegexOpcode.CaseInsensitive) != 0)
{
sb.Append("-Ci");
}
if ((opcode & RegexOpcode.RightToLeft) != 0)
{
sb.Append("-Rtl");
}
if ((opcode & RegexOpcode.Backtracking) != 0)
{
sb.Append("-Back");
}
if ((opcode & RegexOpcode.BacktrackingSecond) != 0)
{
sb.Append("-Back2");
}
opcode &= RegexOpcode.OperatorMask;
switch (opcode)
{
case RegexOpcode.One:
case RegexOpcode.Onerep:
case RegexOpcode.Oneloop:
case RegexOpcode.Oneloopatomic:
case RegexOpcode.Onelazy:
case RegexOpcode.Notone:
case RegexOpcode.Notonerep:
case RegexOpcode.Notoneloop:
case RegexOpcode.Notoneloopatomic:
case RegexOpcode.Notonelazy:
sb.Append(Indent()).Append('\'').Append(RegexCharClass.DescribeChar((char)Codes[opcodeOffset + 1])).Append('\'');
break;
case RegexOpcode.Set:
case RegexOpcode.Setrep:
case RegexOpcode.Setloop:
case RegexOpcode.Setloopatomic:
case RegexOpcode.Setlazy:
sb.Append(Indent()).Append(RegexCharClass.DescribeSet(Strings[Codes[opcodeOffset + 1]]));
break;
case RegexOpcode.Multi:
sb.Append(Indent()).Append('"').Append(Strings[Codes[opcodeOffset + 1]]).Append('"');
break;
case RegexOpcode.Backreference:
case RegexOpcode.TestBackreference:
sb.Append(Indent()).Append("index = ").Append(Codes[opcodeOffset + 1]);
break;
case RegexOpcode.Capturemark:
sb.Append(Indent()).Append("index = ").Append(Codes[opcodeOffset + 1]);
if (Codes[opcodeOffset + 2] != -1)
{
sb.Append(", unindex = ").Append(Codes[opcodeOffset + 2]);
}
break;
case RegexOpcode.Nullcount:
case RegexOpcode.Setcount:
sb.Append(Indent()).Append("value = ").Append(Codes[opcodeOffset + 1]);
break;
case RegexOpcode.Goto:
case RegexOpcode.Lazybranch:
case RegexOpcode.Branchmark:
case RegexOpcode.Lazybranchmark:
case RegexOpcode.Branchcount:
case RegexOpcode.Lazybranchcount:
sb.Append(Indent()).Append("addr = ").Append(Codes[opcodeOffset + 1]);
break;
}
switch (opcode)
{
case RegexOpcode.Onerep:
case RegexOpcode.Oneloop:
case RegexOpcode.Oneloopatomic:
case RegexOpcode.Onelazy:
case RegexOpcode.Notonerep:
case RegexOpcode.Notoneloop:
case RegexOpcode.Notoneloopatomic:
case RegexOpcode.Notonelazy:
case RegexOpcode.Setrep:
case RegexOpcode.Setloop:
case RegexOpcode.Setloopatomic:
case RegexOpcode.Setlazy:
sb.Append(", rep = ").Append(Codes[opcodeOffset + 2] == int.MaxValue ? "inf" : Codes[opcodeOffset + 2]);
break;
case RegexOpcode.Branchcount:
case RegexOpcode.Lazybranchcount:
sb.Append(", limit = ").Append(Codes[opcodeOffset + 2] == int.MaxValue ? "inf" : Codes[opcodeOffset + 2]);
break;
}
return(sb.ToString());
string Indent() => new string(' ', Math.Max(1, 25 - sb.Length));
}