//------------------------------------------------------------------------------
// Copyright (c) Microsoft Corporation. All rights reserved.
//------------------------------------------------------------------------------
// This RegexRunner class is a base class for compiled regex code.
//
// Implementation notes:
//
// RegexRunner provides a common calling convention and a common
// runtime environment for the interpreter and the compiled code.
//
// It provides the driver code that call's the subclass's Go()
// method for either scanning or direct execution.
//
// It also maintains memory allocation for the backtracking stack,
// the grouping stack and the longjump crawlstack, and provides
// methods to push new subpattern match results into (or remove
// backtracked results from) the Match instance.
#define ECMA
namespace System.Text.RegularExpressions
{
using System.Collections;
using System.Diagnostics;
//using System.ComponentModel;
//|
///
abstract public class RegexRunner {
//|
protected internal int runtextbeg; // beginning of text to search
//|
protected internal int runtextend; // end of text to search
//|
protected internal int runtextstart; // starting point for search
//|
protected internal String runtext; // text to search
//|
protected internal int runtextpos; // current position in text
//|
protected internal int [] runtrack; // backtracking stack
//|
protected internal int runtrackpos; // current position in backtracking stack
//|
protected internal int [] runstack; // ordinary stack
//|
protected internal int runstackpos; // current position in ordinary stack
//|
protected internal int [] runcrawl; // longjump crawl stack
//|
protected internal int runcrawlpos; // current position in crawl stack
//|
protected internal int runtrackcount; // count of states that may do backtracking
//|
protected internal Match runmatch; // result object
//|
protected internal Regex runregex; // regex object
//|
protected internal RegexRunner() {}
// Scans the string to find the first match. Uses the Match object
// both to feed text in and as a place to store matches that come out.
//
// All the action is in the abstract Go() method defined by subclasses. Our
// responsibility is to load up the class members (as done here) before
// calling Go.
//
//
//|
protected internal Match Scan(Regex regex, String text, int textbeg, int textend, int textstart, int prevlen, bool quick) {
int bump;
int stoppos;
bool initted = false;
runregex = regex;
runtext = text;
runtextbeg = textbeg;
runtextend = textend;
runtextstart = textstart;
bump = runregex.RightToLeft ? -1 : 1;
stoppos = runregex.RightToLeft ? runtextbeg : runtextend;
runtextpos = textstart;
// If previous match was empty or failed, advance by one before matching
if (prevlen == 0) {
if (runtextpos == stoppos)
return Match.Empty;
runtextpos += bump;
}
for (;;) {
#if DBG
if (runregex.Debug) {
Debug.WriteLine("");
Debug.WriteLine("Search range: from " + runtextbeg.ToString() + " to " + runtextend.ToString());
Debug.WriteLine("Firstchar search starting at " + runtextpos.ToString() + " stopping at " + stoppos.ToString());
}
#endif
if (FindFirstChar()) {
if (!initted) {
InitMatch();
initted = true;
}
#if DBG
if (runregex.Debug) {
Debug.WriteLine("Executing engine starting at " + runtextpos.ToString());
Debug.WriteLine("");
}
#endif
Go();
if (runmatch._matchcount[0] > 0) {
return TidyMatch(quick);
}
// reset state for another go
runtrackpos = runtrack.Length;
runstackpos = runstack.Length;
runcrawlpos = runcrawl.Length;
}
// failure!
if (runtextpos == stoppos) {
TidyMatch(true);
return Match.Empty;
}
// Bump by one and start again
runtextpos += bump;
}
}
// The responsibility of Go() is to run the regular expression at
// runtextpos and call Capture() on all the captured subexpressions,
// then to leave runtextpos at the ending position. It should leave
// runtextpos where it started if there was no match.
//|
protected abstract void Go();
// The responsibility of FindFirstChar() is to advance runtextpos
// until it is at the next position which is a candidate for the
// beginning of a successful match.
//|
protected abstract bool FindFirstChar();
// InitTrackCount must initialize the runtrackcount field; this is
// used to know how large the initial runtrack and runstack arrays
// must be.
//|
protected abstract void InitTrackCount();
// Initializes all the data members that are used by Go()
private void InitMatch() {
// Use a hashtable'ed Match object if the capture numbers are sparse
if (runmatch == null) {
if (runregex.caps != null)
runmatch = new MatchSparse(runregex, runregex.caps, runregex.capsize, runtext, runtextbeg, runtextend - runtextbeg, runtextstart);
else
runmatch = new Match(runregex, runregex.capsize, runtext, runtextbeg, runtextend - runtextbeg, runtextstart);
}
else {
runmatch.Reset(runregex, runtext, runtextbeg, runtextend, runtextstart);
}
// note we test runcrawl, because it is the last one to be allocated
// If there is an alloc failure in the middle of the three allocations,
// we may still return to reuse this instance, and we want to behave
// as if the allocations didn't occur. (we used to test _trackcount != 0)
if (runcrawl != null) {
runtrackpos = runtrack.Length;
runstackpos = runstack.Length;
runcrawlpos = runcrawl.Length;
return;
}
InitTrackCount();
int tracksize = runtrackcount * 8;
int stacksize = runtrackcount * 8;
if (tracksize < 32)
tracksize = 32;
if (stacksize < 16)
stacksize = 16;
runtrack = new int[tracksize];
runtrackpos = tracksize;
runstack = new int[stacksize];
runstackpos = stacksize;
runcrawl = new int[32];
runcrawlpos = 32;
}
// Put match in its canonical form before returning it.
private Match TidyMatch(bool quick) {
if (!quick) {
Match match = runmatch;
runmatch = null;
match.Tidy(runtextpos);
return match;
}
else {
// in quick mode, a successful match returns null, and
// the allocated match object is left in the cache
return null;
}
}
// Called by the implementation of Go() to increase the size of storage
//|
protected void EnsureStorage() {
if (runstackpos < runtrackcount * 4)
DoubleStack();
if (runtrackpos < runtrackcount * 4)
DoubleTrack();
}
// Called by the implementation of Go() to decide whether the pos
// at the specified index is a boundary or not. It's just not worth
// emitting inline code for this logic.
//|
protected bool IsBoundary(int index, int startpos, int endpos) {
return (index > startpos && RegexCharClass.IsWordChar(runtext[index - 1])) !=
(index < endpos && RegexCharClass.IsWordChar(runtext[index]));
}
//|
protected bool IsECMABoundary(int index, int startpos, int endpos) {
return (index > startpos && RegexCharClass.IsECMAWordChar(runtext[index - 1])) !=
(index < endpos && RegexCharClass.IsECMAWordChar(runtext[index]));
}
//|
protected static bool CharInSet(char ch, String set, String category) {
return RegexCharClass.CharInSet(ch, set, category);
}
// Called by the implementation of Go() to increase the size of the
// backtracking stack.
//|
protected void DoubleTrack() {
int[] newtrack;
newtrack = new int[runtrack.Length * 2];
System.Array.Copy(runtrack, 0, newtrack, runtrack.Length, runtrack.Length);
runtrackpos += runtrack.Length;
runtrack = newtrack;
}
// Called by the implementation of Go() to increase the size of the
// grouping stack.
//|
protected void DoubleStack() {
int[] newstack;
newstack = new int[runstack.Length * 2];
System.Array.Copy(runstack, 0, newstack, runstack.Length, runstack.Length);
runstackpos += runstack.Length;
runstack = newstack;
}
// Increases the size of the longjump unrolling stack.
//|
protected void DoubleCrawl() {
int[] newcrawl;
newcrawl = new int[runcrawl.Length * 2];
System.Array.Copy(runcrawl, 0, newcrawl, runcrawl.Length, runcrawl.Length);
runcrawlpos += runcrawl.Length;
runcrawl = newcrawl;
}
// Save a number on the longjump unrolling stack
//|
protected void Crawl(int i) {
if (runcrawlpos == 0)
DoubleCrawl();
runcrawl[--runcrawlpos] = i;
}
// Remove a number from the longjump unrolling stack
//|
protected int Popcrawl() {
return runcrawl[runcrawlpos++];
}
// Get the height of the stack
//|
protected int Crawlpos() {
return runcrawl.Length - runcrawlpos;
}
// Called by Go() to capture a subexpression. Note that the
// capnum used here has already been mapped to a non-sparse
// index (by the code generator RegexWriter).
//|
protected void Capture(int capnum, int start, int end) {
if (end < start) {
int T;
T = end;
end = start;
start = T;
}
Crawl(capnum);
runmatch.AddMatch(capnum, start, end - start);
}
// Called by Go() to capture a subexpression. Note that the
// capnum used here has already been mapped to a non-sparse
// index (by the code generator RegexWriter).
//|
protected void TransferCapture(int capnum, int uncapnum, int start, int end) {
int start2;
int end2;
// these are the two intervals that are cancelling each other
if (end < start) {
int T;
T = end;
end = start;
start = T;
}
start2 = MatchIndex(uncapnum);
end2 = start2 + MatchLength(uncapnum);
// The new capture gets the innermost defined interval
if (start >= end2) {
end = start;
start = end2;
}
else if (end <= start2) {
start = start2;
}
else {
if (end > end2)
end = end2;
if (start2 > start)
start = start2;
}
Crawl(uncapnum);
runmatch.BalanceMatch(uncapnum);
if (capnum != -1) {
Crawl(capnum);
runmatch.AddMatch(capnum, start, end - start);
}
}
// Called by Go() to revert the last capture
//|
protected void Uncapture() {
int capnum = Popcrawl();
runmatch.RemoveMatch(capnum);
}
// Call out to runmatch to get around visibility issues
//|
protected bool IsMatched(int cap) {
return runmatch.IsMatched(cap);
}
// Call out to runmatch to get around visibility issues
//|
protected int MatchIndex(int cap) {
return runmatch.MatchIndex(cap);
}
// Call out to runmatch to get around visibility issues
//|
protected int MatchLength(int cap) {
return runmatch.MatchLength(cap);
}
#if DBG
// Dump the current state
//|
public virtual void DumpState() {
Debug.WriteLine("Text: " + TextposDescription());
Debug.WriteLine("Track: " + StackDescription(runtrack, runtrackpos));
Debug.WriteLine("Stack: " + StackDescription(runstack, runstackpos));
}
internal static String StackDescription(int[] A, int Index) {
StringBuilder Sb = new StringBuilder();
Sb.Append(A.Length - Index);
Sb.Append('/');
Sb.Append(A.Length);
if (Sb.Length < 8)
Sb.Append(' ',8 - Sb.Length);
Sb.Append("(");
for (int i = Index; i < A.Length; i++) {
if (i > Index)
Sb.Append(' ');
Sb.Append(A[i]);
}
Sb.Append(')');
return Sb.ToString();
}
internal virtual String TextposDescription() {
StringBuilder Sb = new StringBuilder();
int remaining;
Sb.Append(runtextpos);
if (Sb.Length < 8)
Sb.Append(' ',8 - Sb.Length);
if (runtextpos > runtextbeg)
Sb.Append(RegexCharClass.CharDescription(runtext[runtextpos - 1]));
else
Sb.Append('^');
Sb.Append('>');
remaining = runtextend - runtextpos;
for (int i = runtextpos; i < runtextend; i++) {
Sb.Append(RegexCharClass.CharDescription(runtext[i]));
}
if (Sb.Length >= 64) {
Sb.Length = 61;
Sb.Append("...");
}
else {
Sb.Append('$');
}
return Sb.ToString();
}
#endif
}
}