Adapting lpeglabel-1.5 to the codebase of lpeg-1.0.0lpeg-1.0.0

1 files changed, 28 insertions, 56 deletions

diff --git a/lpcode.c b/lpcode.c
index 6cf2933..08c0bf0 100644
--- a/lpcode.c
+++ b/lpcode.c
@@ -1,5 +1,5 @@
 /*
-** $Id: lpcode.c,v 1.24 2016/09/15 17:46:13 roberto Exp $
+** $Id: lpcode.c,v 1.23 2015/06/12 18:36:47 roberto Exp $
 ** Copyright 2007, Lua.org & PUC-Rio  (see 'lpeg.html' for license)
 */
 
@@ -126,27 +126,6 @@ int tocharset (TTree *tree, Charset *cs) {
 
 
 /*
-** Visit a TCall node taking care to stop recursion. If node not yet
-** visited, return 'f(sib2(tree))', otherwise return 'def' (default
-** value)
-*/
-static int callrecursive (TTree *tree, int f (TTree *t), int def) {
-  int key = tree->key;
-  assert(tree->tag == TCall);
-  assert(sib2(tree)->tag == TRule);
-  if (key == 0)  /* node already visited? */
-    return def;  /* return default value */
-  else {  /* first visit */
-    int result;
-    tree->key = 0;  /* mark call as already visited */
-    result = f(sib2(tree));  /* go to called rule */
-    tree->key = key;  /* restore tree */
-    return result;
-  }
-}
-
-
-/*
 ** Check whether a pattern tree has captures
 */
 int hascaptures (TTree *tree) {
@@ -155,17 +134,14 @@ int hascaptures (TTree *tree) {
     case TCapture: case TRunTime:
       return 1;
     case TCall:
-      return callrecursive(tree, hascaptures, 0);
-    case TRule:  /* do not follow siblings */
-      tree = sib1(tree); goto tailcall;
+      tree = sib2(tree); goto tailcall;  /* return hascaptures(sib2(tree)); */
     case TOpenCall: assert(0);
     default: {
       switch (numsiblings[tree->tag]) {
         case 1:  /* return hascaptures(sib1(tree)); */
           tree = sib1(tree); goto tailcall;
         case 2:
-          if (hascaptures(sib1(tree)))
-            return 1;
+          if (hascaptures(sib1(tree))) return 1;
           /* else return hascaptures(sib2(tree)); */
           tree = sib2(tree); goto tailcall;
         default: assert(numsiblings[tree->tag] == 0); return 0;
@@ -232,9 +208,9 @@ int checkaux (TTree *tree, int pred) {
 
 /*
 ** number of characters to match a pattern (or -1 if variable)
+** ('count' avoids infinite loops for grammars)
 */
-int fixedlen (TTree *tree) {
-  int len = 0;  /* to accumulate in tail calls */
+int fixedlenx (TTree *tree, int count, int len) {
  tailcall:
   switch (tree->tag) {
     case TChar: case TSet: case TAny:
@@ -245,29 +221,26 @@ int fixedlen (TTree *tree) {
     case TThrow: /* labeled failure */
       return -1;
     case TCapture: case TRule: case TGrammar:
-      /* return fixedlen(sib1(tree)); */
+      /* return fixedlenx(sib1(tree), count); */
       tree = sib1(tree); goto tailcall;
-    case TCall: {
-      int n1 = callrecursive(tree, fixedlen, -1);
-      if (n1 < 0)
-        return -1;
-      else
-        return len + n1;
-    }
-    case TSeq: { 
-      int n1 = fixedlen(sib1(tree));
-      if (n1 < 0)
-        return -1;
-      /* else return fixedlen(sib2(tree)) + len; */
-      len += n1; tree = sib2(tree); goto tailcall;
+    case TCall:
+      if (count++ >= MAXRULES)
+        return -1;  /* may be a loop */
+      /* else return fixedlenx(sib2(tree), count); */
+      tree = sib2(tree); goto tailcall;
+    case TSeq: {
+      len = fixedlenx(sib1(tree), count, len);
+      if (len < 0) return -1;
+      /* else return fixedlenx(sib2(tree), count, len); */
+      tree = sib2(tree); goto tailcall;
     }
-    case TChoice: { 
-      int n1 = fixedlen(sib1(tree));
-      int n2 = fixedlen(sib2(tree));
-      if (n1 != n2 || n1 < 0)
-        return -1;
-      else
-        return len + n1;
+    case TChoice: {
+      int n1, n2;
+      n1 = fixedlenx(sib1(tree), count, len);
+      if (n1 < 0) return -1;
+      n2 = fixedlenx(sib2(tree), count, len);
+      if (n1 == n2) return n1;
+      else return -1;
     }
     default: assert(0); return 0;
   };
@@ -311,7 +284,7 @@ static int getfirst (TTree *tree, const Charset *follow, Charset *firstset) {
       loopset(i, firstset->cs[i] = fullset->cs[i]);
       return 1;
     } 
-    case TChoice: { 
+    case TChoice: {
       Charset csaux;
       int e1 = getfirst(sib1(tree), follow, firstset);
       int e2 = getfirst(sib2(tree), follow, &csaux);
@@ -396,7 +369,7 @@ static int headfail (TTree *tree) {
       if (!nofail(sib2(tree))) return 0;
       /* else return headfail(sib1(tree)); */
       tree = sib1(tree); goto tailcall;
-    case TChoice: 
+    case TChoice:
       if (!headfail(sib1(tree))) return 0;
       /* else return headfail(sib2(tree)); */
       tree = sib2(tree); goto tailcall;
@@ -769,10 +742,9 @@ static void codeand (CompileState *compst, TTree *tree, int tt) {
 
 
 /*
-** Captures: if pattern has fixed (and not too big) length, and it
-** has no nested captures, use a single IFullCapture instruction
-** after the match; otherwise, enclose the pattern with OpenCapture -
-** CloseCapture.
+** Captures: if pattern has fixed (and not too big) length, use
+** a single IFullCapture instruction after the match; otherwise,
+** enclose the pattern with OpenCapture - CloseCapture.
 */
 static void codecapture (CompileState *compst, TTree *tree, int tt,
                          const Charset *fl) {