/// <summary> /// The top level RegexCode generator. It does a depth-first walk /// through the tree and calls EmitFragment to emits code before /// and after each child of an interior node, and at each leaf. /// </summary> public RegexCode RegexCodeFromRegexTree(RegexTree tree) { Span <int> emittedSpan = stackalloc int[EmittedSize]; Span <int> intStackSpan = stackalloc int[IntStackSize]; RegexWriter writer = new RegexWriter(emittedSpan, intStackSpan); // construct sparse capnum mapping if some numbers are unused int capsize; if (tree._capnumlist == null || tree._captop == tree._capnumlist.Length) { capsize = tree._captop; writer._caps = null; } else { capsize = tree._capnumlist.Length; writer._caps = tree._caps; for (int i = 0; i < tree._capnumlist.Length; i++) { writer._caps[tree._capnumlist[i]] = i; } } RegexNode curNode = tree._root; int curChild = 0; writer.Emit(RegexCode.Lazybranch, 0); for (; ;) { if (curNode._children == null) { writer.EmitFragment(curNode._type, curNode, 0); } else if (curChild < curNode._children.Count) { writer.EmitFragment(curNode._type | BeforeChild, curNode, curChild); curNode = curNode._children[curChild]; writer._intStack.Append(curChild); curChild = 0; continue; } if (writer._intStack.Length == 0) { break; } curChild = writer._intStack.Pop(); curNode = curNode._next; writer.EmitFragment(curNode._type | AfterChild, curNode, curChild); curChild++; } writer.PatchJump(0, writer._emitted.Length); writer.Emit(RegexCode.Stop); RegexPrefix fcPrefix = RegexFCD.FirstChars(tree); RegexPrefix prefix = RegexFCD.Prefix(tree); bool rtl = ((tree._options & RegexOptions.RightToLeft) != 0); CultureInfo culture = (tree._options & RegexOptions.CultureInvariant) != 0 ? CultureInfo.InvariantCulture : CultureInfo.CurrentCulture; RegexBoyerMoore bmPrefix; if (prefix != null && prefix.Prefix.Length > 0) { bmPrefix = new RegexBoyerMoore(prefix.Prefix, prefix.CaseInsensitive, rtl, culture); } else { bmPrefix = null; } int anchors = RegexFCD.Anchors(tree); int[] emitted = writer._emitted.AsReadOnlySpan().ToArray(); // Cleaning up and returning the borrowed arrays writer._emitted.Dispose(); writer._intStack.Dispose(); return(new RegexCode(emitted, writer._stringTable, writer._trackCount, writer._caps, capsize, bmPrefix, fcPrefix, anchors, rtl)); }