ENH: Added kwsys library for platform-independent system tools.

1 files changed, 1211 insertions, 0 deletions

diff --git a/Source/kwsys/RegularExpression.cxx b/Source/kwsys/RegularExpression.cxx
new file mode 100644
index 0000000..f9a3291
--- /dev/null
+++ b/Source/kwsys/RegularExpression.cxx
@@ -0,0 +1,1211 @@
+/*=========================================================================
+
+  Program:   KWSys - Kitware System Library
+  Module:    $RCSfile$
+  Language:  C++
+  Date:      $Date$
+  Version:   $Revision$
+
+  Copyright (c) 2002 Kitware, Inc., Insight Consortium.  All rights reserved.
+  See http://www.cmake.org/HTML/Copyright.html for details.
+
+     This software is distributed WITHOUT ANY WARRANTY; without even 
+     the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR 
+     PURPOSE.  See the above copyright notices for more information.
+
+=========================================================================*/
+//
+// Copyright (C) 1991 Texas Instruments Incorporated.
+//
+// Permission is granted to any individual or institution to use, copy, modify,
+// and distribute this software, provided that this complete copyright and
+// permission notice is maintained, intact, in all copies and supporting
+// documentation.
+//
+// Texas Instruments Incorporated provides this software "as is" without
+// express or implied warranty.
+//
+//
+// Created: MNF 06/13/89  Initial Design and Implementation
+// Updated: LGO 08/09/89  Inherit from Generic
+// Updated: MBN 09/07/89  Added conditional exception handling
+// Updated: MBN 12/15/89  Sprinkled "const" qualifiers all over the place!
+// Updated: DLS 03/22/91  New lite version
+//
+
+#include <RegularExpression.hxx>        // Include class specification 
+#include <stdio.h>
+
+namespace KWSYS_NAMESPACE
+{
+
+// RegularExpression -- Copies the given regular expression.
+RegularExpression::RegularExpression (const RegularExpression& rxp) {
+  if ( !rxp.program )
+    {
+    this->program = 0;
+    return;
+    }
+  int ind; 
+  this->progsize = rxp.progsize;                // Copy regular expression size
+  this->program = new char[this->progsize];     // Allocate storage
+  for(ind=this->progsize; ind-- != 0;)          // Copy regular expresion
+    this->program[ind] = rxp.program[ind];
+  this->startp[0] = rxp.startp[0];              // Copy pointers into last
+  this->endp[0] = rxp.endp[0];                  // Successful "find" operation
+  this->regmust = rxp.regmust;                  // Copy field
+  if (rxp.regmust != 0) {
+    char* dum = rxp.program;
+    ind = 0;
+    while (dum != rxp.regmust) {
+      ++dum;
+      ++ind;
+    }
+    this->regmust = this->program + ind;
+  }
+  this->regstart = rxp.regstart;                // Copy starting index
+  this->reganch = rxp.reganch;                  // Copy remaining private data
+  this->regmlen = rxp.regmlen;                  // Copy remaining private data
+}
+
+// operator== -- Returns true if two regular expressions have the same
+// compiled program for pattern matching.
+bool RegularExpression::operator== (const RegularExpression& rxp) const {
+  if (this != &rxp) {                           // Same address?
+    int ind = this->progsize;                   // Get regular expression size
+    if (ind != rxp.progsize)                    // If different size regexp
+      return false;                             // Return failure
+    while(ind-- != 0)                           // Else while still characters
+      if(this->program[ind] != rxp.program[ind]) // If regexp are different    
+        return false;                            // Return failure             
+  }
+  return true;                                  // Else same, return success  
+}
+
+
+// deep_equal -- Returns true if have the same compiled regular expressions
+// and the same start and end pointers.
+
+bool RegularExpression::deep_equal (const RegularExpression& rxp) const {
+  int ind = this->progsize;                     // Get regular expression size
+  if (ind != rxp.progsize)                      // If different size regexp
+    return false;                               // Return failure
+  while(ind-- != 0)                             // Else while still characters
+    if(this->program[ind] != rxp.program[ind])  // If regexp are different    
+      return false;                             // Return failure             
+  return (this->startp[0] == rxp.startp[0] &&   // Else if same start/end ptrs,
+          this->endp[0] == rxp.endp[0]);        // Return true
+}   
+
+// The remaining code in this file is derived from the  regular expression code
+// whose  copyright statement appears  below.  It has been  changed to work
+// with the class concepts of C++ and COOL.
+
+/*
+ * compile and find 
+ *
+ *      Copyright (c) 1986 by University of Toronto.
+ *      Written by Henry Spencer.  Not derived from licensed software.
+ *
+ *      Permission is granted to anyone to use this software for any
+ *      purpose on any computer system, and to redistribute it freely,
+ *      subject to the following restrictions:
+ *
+ *      1. The author is not responsible for the consequences of use of
+ *              this software, no matter how awful, even if they arise
+ *              from defects in it.
+ *
+ *      2. The origin of this software must not be misrepresented, either
+ *              by explicit claim or by omission.
+ *
+ *      3. Altered versions must be plainly marked as such, and must not
+ *              be misrepresented as being the original software.
+ *
+ * Beware that some of this code is subtly aware of the way operator
+ * precedence is structured in regular expressions.  Serious changes in
+ * regular-expression syntax might require a total rethink.
+ */
+
+/*
+ * The "internal use only" fields in regexp.h are present to pass info from
+ * compile to execute that permits the execute phase to run lots faster on
+ * simple cases.  They are:
+ *
+ * regstart     char that must begin a match; '\0' if none obvious
+ * reganch      is the match anchored (at beginning-of-line only)?
+ * regmust      string (pointer into program) that match must include, or NULL
+ * regmlen      length of regmust string
+ *
+ * Regstart and reganch permit very fast decisions on suitable starting points
+ * for a match, cutting down the work a lot.  Regmust permits fast rejection
+ * of lines that cannot possibly match.  The regmust tests are costly enough
+ * that compile() supplies a regmust only if the r.e. contains something
+ * potentially expensive (at present, the only such thing detected is * or +
+ * at the start of the r.e., which can involve a lot of backup).  Regmlen is
+ * supplied because the test in find() needs it and compile() is computing
+ * it anyway.
+ */
+
+/*
+ * Structure for regexp "program".  This is essentially a linear encoding
+ * of a nondeterministic finite-state machine (aka syntax charts or
+ * "railroad normal form" in parsing technology).  Each node is an opcode
+ * plus a "next" pointer, possibly plus an operand.  "Next" pointers of
+ * all nodes except BRANCH implement concatenation; a "next" pointer with
+ * a BRANCH on both ends of it is connecting two alternatives.  (Here we
+ * have one of the subtle syntax dependencies:  an individual BRANCH (as
+ * opposed to a collection of them) is never concatenated with anything
+ * because of operator precedence.)  The operand of some types of node is
+ * a literal string; for others, it is a node leading into a sub-FSM.  In
+ * particular, the operand of a BRANCH node is the first node of the branch.
+ * (NB this is *not* a tree structure:  the tail of the branch connects
+ * to the thing following the set of BRANCHes.)  The opcodes are:
+ */
+
+// definition   number  opnd?   meaning
+#define END     0               // no   End of program.
+#define BOL     1               // no   Match "" at beginning of line.
+#define EOL     2               // no   Match "" at end of line.
+#define ANY     3               // no   Match any one character.
+#define ANYOF   4               // str  Match any character in this string.
+#define ANYBUT  5               // str  Match any character not in this
+                                // string.
+#define BRANCH  6               // node Match this alternative, or the
+                                // next...
+#define BACK    7               // no   Match "", "next" ptr points backward.
+#define EXACTLY 8               // str  Match this string.
+#define NOTHING 9               // no   Match empty string.
+#define STAR    10              // node Match this (simple) thing 0 or more
+                                // times.
+#define PLUS    11              // node Match this (simple) thing 1 or more
+                                // times.
+#define OPEN    20              // no   Mark this point in input as start of
+                                // #n.
+// OPEN+1 is number 1, etc.
+#define CLOSE   30              // no   Analogous to OPEN.
+
+/*
+ * Opcode notes:
+ *
+ * BRANCH       The set of branches constituting a single choice are hooked
+ *              together with their "next" pointers, since precedence prevents
+ *              anything being concatenated to any individual branch.  The
+ *              "next" pointer of the last BRANCH in a choice points to the
+ *              thing following the whole choice.  This is also where the
+ *              final "next" pointer of each individual branch points; each
+ *              branch starts with the operand node of a BRANCH node.
+ *
+ * BACK         Normal "next" pointers all implicitly point forward; BACK
+ *              exists to make loop structures possible.
+ *
+ * STAR,PLUS    '?', and complex '*' and '+', are implemented as circular
+ *              BRANCH structures using BACK.  Simple cases (one character
+ *              per match) are implemented with STAR and PLUS for speed
+ *              and to minimize recursive plunges.
+ *
+ * OPEN,CLOSE   ...are numbered at compile time.
+ */
+
+/*
+ * A node is one char of opcode followed by two chars of "next" pointer.
+ * "Next" pointers are stored as two 8-bit pieces, high order first.  The
+ * value is a positive offset from the opcode of the node containing it.
+ * An operand, if any, simply follows the node.  (Note that much of the
+ * code generation knows about this implicit relationship.)
+ *
+ * Using two bytes for the "next" pointer is vast overkill for most things,
+ * but allows patterns to get big without disasters.
+ */
+
+#define OP(p)           (*(p))
+#define NEXT(p)         (((*((p)+1)&0377)<<8) + (*((p)+2)&0377))
+#define OPERAND(p)      ((p) + 3)
+
+const unsigned char MAGIC = 0234;
+/*
+ * Utility definitions.
+ */
+
+#define UCHARAT(p)      ((const unsigned char*)(p))[0]
+
+
+#define FAIL(m) { regerror(m); return(0); }
+#define ISMULT(c)       ((c) == '*' || (c) == '+' || (c) == '?')
+#define META    "^$.[()|?+*\\"
+
+
+/*
+ * Flags to be passed up and down.
+ */
+#define HASWIDTH        01      // Known never to match null string.
+#define SIMPLE          02      // Simple enough to be STAR/PLUS operand.
+#define SPSTART         04      // Starts with * or +.
+#define WORST           0       // Worst case.
+
+
+
+/////////////////////////////////////////////////////////////////////////
+//
+//  COMPILE AND ASSOCIATED FUNCTIONS
+//
+/////////////////////////////////////////////////////////////////////////
+
+
+/*
+ * Global work variables for compile().
+ */
+static const char* regparse;    // Input-scan pointer.
+static       int   regnpar;     // () count.
+static       char  regdummy;
+static       char* regcode;     // Code-emit pointer; &regdummy = don't.
+static       long  regsize;     // Code size.
+
+/*
+ * Forward declarations for compile()'s friends.
+ */
+// #ifndef static
+// #define      static  static
+// #endif
+static       char* reg (int, int*);
+static       char* regbranch (int*);
+static       char* regpiece (int*);
+static       char* regatom (int*);
+static       char* regnode (char);
+static const char* regnext (register const char*);
+static       char* regnext (register char*);
+static void        regc (unsigned char);
+static void        reginsert (char, char*);
+static void        regtail (char*, const char*);
+static void        regoptail (char*, const char*);
+
+#ifdef STRCSPN
+static int strcspn ();
+#endif
+
+
+
+/*
+ * We can't allocate space until we know how big the compiled form will be,
+ * but we can't compile it (and thus know how big it is) until we've got a
+ * place to put the code.  So we cheat:  we compile it twice, once with code
+ * generation turned off and size counting turned on, and once "for real".
+ * This also means that we don't allocate space until we are sure that the
+ * thing really will compile successfully, and we never have to move the
+ * code and thus invalidate pointers into it.  (Note that it has to be in
+ * one piece because free() must be able to free it all.)
+ *
+ * Beware that the optimization-preparation code in here knows about some
+ * of the structure of the compiled regexp.
+ */
+
+
+// compile -- compile a regular expression into internal code
+// for later pattern matching.
+
+bool RegularExpression::compile (const char* exp) {
+    register const char* scan;
+    register const char* longest;
+    register unsigned long len;
+             int         flags;
+
+    if (exp == 0) {
+      //RAISE Error, SYM(RegularExpression), SYM(No_Expr),
+      printf ("RegularExpression::compile(): No expression supplied.\n");
+      return false;
+    }
+
+    // First pass: determine size, legality.
+    regparse = exp;
+    regnpar = 1;
+    regsize = 0L;
+    regcode = &regdummy;
+    regc(MAGIC);
+    if(!reg(0, &flags))
+      {
+        printf ("RegularExpression::compile(): Error in compile.\n");
+        return false;
+      }
+    this->startp[0] = this->endp[0] = this->searchstring = 0;
+
+    // Small enough for pointer-storage convention? 
+    if (regsize >= 32767L) {    // Probably could be 65535L. 
+      //RAISE Error, SYM(RegularExpression), SYM(Expr_Too_Big),
+      printf ("RegularExpression::compile(): Expression too big.\n");
+      return false;
+    }
+
+    // Allocate space. 
+//#ifndef WIN32
+    if (this->program != 0) delete [] this->program;  
+//#endif
+    this->program = new char[regsize];
+    this->progsize = (int) regsize;
+
+    if (this->program == 0) {
+      //RAISE Error, SYM(RegularExpression), SYM(Out_Of_Memory),
+      printf ("RegularExpression::compile(): Out of memory.\n"); 
+      return false;
+    }
+
+    // Second pass: emit code.
+    regparse = exp;
+    regnpar = 1;
+    regcode = this->program;
+    regc(MAGIC);
+    reg(0, &flags);
+
+    // Dig out information for optimizations.
+    this->regstart = '\0';              // Worst-case defaults.
+    this->reganch = 0;
+    this->regmust = 0;
+    this->regmlen = 0;
+    scan = this->program + 1;   // First BRANCH.
+    if (OP(regnext(scan)) == END) {     // Only one top-level choice.
+        scan = OPERAND(scan);
+
+        // Starting-point info.
+        if (OP(scan) == EXACTLY)
+            this->regstart = *OPERAND(scan);
+        else if (OP(scan) == BOL)
+            this->reganch++;
+
+         //
+         // If there's something expensive in the r.e., find the longest
+         // literal string that must appear and make it the regmust.  Resolve
+         // ties in favor of later strings, since the regstart check works
+         // with the beginning of the r.e. and avoiding duplication
+         // strengthens checking.  Not a strong reason, but sufficient in the
+         // absence of others. 
+         //
+        if (flags & SPSTART) {
+            longest = 0;
+            len = 0;
+            for (; scan != 0; scan = regnext(scan))
+                if (OP(scan) == EXACTLY && strlen(OPERAND(scan)) >= len) {
+                    longest = OPERAND(scan);
+                    len = int(strlen(OPERAND(scan)));
+                }
+            this->regmust = longest;
+            this->regmlen = len;
+        }
+    }
+    return true;
+}
+
+
+/*
+ - reg - regular expression, i.e. main body or parenthesized thing
+ *
+ * Caller must absorb opening parenthesis.
+ *
+ * Combining parenthesis handling with the base level of regular expression
+ * is a trifle forced, but the need to tie the tails of the branches to what
+ * follows makes it hard to avoid.
+ */
+static char* reg (int paren, int *flagp) {
+    register char* ret;
+    register char* br;
+    register char* ender;
+    register int   parno =0;
+             int   flags;
+
+    *flagp = HASWIDTH;          // Tentatively.
+
+    // Make an OPEN node, if parenthesized.
+    if (paren) {
+        if (regnpar >= RegularExpressionNSUBEXP) {
+          //RAISE Error, SYM(RegularExpression), SYM(Too_Many_Parens),
+          printf ("RegularExpression::compile(): Too many parentheses.\n");
+          return 0;
+        }
+        parno = regnpar;
+        regnpar++;
+        ret = regnode(OPEN + parno);
+    }
+    else
+        ret = 0;
+
+    // Pick up the branches, linking them together.
+    br = regbranch(&flags);
+    if (br == 0)
+        return (0);
+    if (ret != 0)
+        regtail(ret, br);       // OPEN -> first.
+    else
+        ret = br;
+    if (!(flags & HASWIDTH))
+        *flagp &= ~HASWIDTH;
+    *flagp |= flags & SPSTART;
+    while (*regparse == '|') {
+        regparse++;
+        br = regbranch(&flags);
+        if (br == 0)
+            return (0);
+        regtail(ret, br);       // BRANCH -> BRANCH.
+        if (!(flags & HASWIDTH))
+            *flagp &= ~HASWIDTH;
+        *flagp |= flags & SPSTART;
+      }
+
+    // Make a closing node, and hook it on the end.
+    ender = regnode((paren) ? CLOSE + parno : END);
+    regtail(ret, ender);
+
+    // Hook the tails of the branches to the closing node.
+    for (br = ret; br != 0; br = regnext(br))
+        regoptail(br, ender);
+
+    // Check for proper termination.
+    if (paren && *regparse++ != ')') {
+        //RAISE Error, SYM(RegularExpression), SYM(Unmatched_Parens),
+        printf ("RegularExpression::compile(): Unmatched parentheses.\n");
+        return 0;
+    }
+    else if (!paren && *regparse != '\0') {
+        if (*regparse == ')') {
+            //RAISE Error, SYM(RegularExpression), SYM(Unmatched_Parens),
+            printf ("RegularExpression::compile(): Unmatched parentheses.\n");
+            return 0;
+        }
+        else {
+            //RAISE Error, SYM(RegularExpression), SYM(Internal_Error),
+            printf ("RegularExpression::compile(): Internal error.\n");
+            return 0;
+        }
+        // NOTREACHED
+    }
+    return (ret);
+}
+
+
+/*
+ - regbranch - one alternative of an | operator
+ *
+ * Implements the concatenation operator.
+ */
+static char* regbranch (int *flagp) {
+    register char* ret;
+    register char* chain;
+    register char* latest;
+    int                  flags;
+
+    *flagp = WORST;             // Tentatively.
+
+    ret = regnode(BRANCH);
+    chain = 0;
+    while (*regparse != '\0' && *regparse != '|' && *regparse != ')') {
+        latest = regpiece(&flags);
+        if (latest == 0)
+            return (0);
+        *flagp |= flags & HASWIDTH;
+        if (chain == 0) // First piece.
+            *flagp |= flags & SPSTART;
+        else
+            regtail(chain, latest);
+        chain = latest;
+    }
+    if (chain == 0)             // Loop ran zero times.
+        regnode(NOTHING);
+
+    return (ret);
+}
+
+
+/*
+ - regpiece - something followed by possible [*+?]
+ *
+ * Note that the branching code sequences used for ? and the general cases
+ * of * and + are somewhat optimized:  they use the same NOTHING node as
+ * both the endmarker for their branch list and the body of the last branch.
+ * It might seem that this node could be dispensed with entirely, but the
+ * endmarker role is not redundant.
+ */
+static char* regpiece (int *flagp) {
+    register char* ret;
+    register char  op;
+    register char* next;
+    int            flags;
+
+    ret = regatom(&flags);
+    if (ret == 0)
+        return (0);
+
+    op = *regparse;
+    if (!ISMULT(op)) {
+        *flagp = flags;
+        return (ret);
+    }
+
+    if (!(flags & HASWIDTH) && op != '?') {
+        //RAISE Error, SYM(RegularExpression), SYM(Empty_Operand),
+        printf ("RegularExpression::compile() : *+ operand could be empty.\n");
+        return 0;
+    }
+    *flagp = (op != '+') ? (WORST | SPSTART) : (WORST | HASWIDTH);
+
+    if (op == '*' && (flags & SIMPLE))
+        reginsert(STAR, ret);
+    else if (op == '*') {
+        // Emit x* as (x&|), where & means "self".
+        reginsert(BRANCH, ret); // Either x
+        regoptail(ret, regnode(BACK));  // and loop
+        regoptail(ret, ret);    // back
+        regtail(ret, regnode(BRANCH));  // or
+        regtail(ret, regnode(NOTHING)); // null.
+    }
+    else if (op == '+' && (flags & SIMPLE))
+        reginsert(PLUS, ret);
+    else if (op == '+') {
+        // Emit x+ as x(&|), where & means "self".
+        next = regnode(BRANCH); // Either
+        regtail(ret, next);
+        regtail(regnode(BACK), ret);    // loop back
+        regtail(next, regnode(BRANCH)); // or
+        regtail(ret, regnode(NOTHING)); // null.
+    }
+    else if (op == '?') {
+        // Emit x? as (x|)
+        reginsert(BRANCH, ret); // Either x
+        regtail(ret, regnode(BRANCH));  // or
+        next = regnode(NOTHING);// null.
+        regtail(ret, next);
+        regoptail(ret, next);
+    }
+    regparse++;
+    if (ISMULT(*regparse)) {
+        //RAISE Error, SYM(RegularExpression), SYM(Nested_Operand),
+        printf ("RegularExpression::compile(): Nested *?+.\n");
+        return 0;
+    }
+    return (ret);
+}
+
+
+/*
+ - regatom - the lowest level
+ *
+ * Optimization:  gobbles an entire sequence of ordinary characters so that
+ * it can turn them into a single node, which is smaller to store and
+ * faster to run.  Backslashed characters are exceptions, each becoming a
+ * separate node; the code is simpler that way and it's not worth fixing.
+ */
+static char* regatom (int *flagp) {
+    register char* ret;
+             int   flags;
+
+    *flagp = WORST;             // Tentatively.
+
+    switch (*regparse++) {
+        case '^':
+            ret = regnode(BOL);
+            break;
+        case '$':
+            ret = regnode(EOL);
+            break;
+        case '.':
+            ret = regnode(ANY);
+            *flagp |= HASWIDTH | SIMPLE;
+            break;
+        case '[':{
+                register int    rxpclass;
+                register int    rxpclassend;
+
+                if (*regparse == '^') { // Complement of range.
+                    ret = regnode(ANYBUT);
+                    regparse++;
+                }
+                else
+                    ret = regnode(ANYOF);
+                if (*regparse == ']' || *regparse == '-')
+                    regc(*regparse++);
+                while (*regparse != '\0' && *regparse != ']') {
+                    if (*regparse == '-') {
+                        regparse++;
+                        if (*regparse == ']' || *regparse == '\0')
+                            regc('-');
+                        else {
+                            rxpclass = UCHARAT(regparse - 2) + 1;
+                            rxpclassend = UCHARAT(regparse);
+                            if (rxpclass > rxpclassend + 1) {
+                               //RAISE Error, SYM(RegularExpression), SYM(Invalid_Range),
+                               printf ("RegularExpression::compile(): Invalid range in [].\n");
+                               return 0;
+                            }
+                            for (; rxpclass <= rxpclassend; rxpclass++)
+                                regc(rxpclass);
+                            regparse++;
+                        }
+                    }
+                    else
+                        regc(*regparse++);
+                }
+                regc('\0');
+                if (*regparse != ']') {
+                    //RAISE Error, SYM(RegularExpression), SYM(Unmatched_Bracket),
+                    printf ("RegularExpression::compile(): Unmatched [].\n");
+                    return 0;
+                }
+                regparse++;
+                *flagp |= HASWIDTH | SIMPLE;
+            }
+            break;
+        case '(':
+            ret = reg(1, &flags);
+            if (ret == 0)
+                return (0);
+            *flagp |= flags & (HASWIDTH | SPSTART);
+            break;
+        case '\0':
+        case '|':
+        case ')':
+            //RAISE Error, SYM(RegularExpression), SYM(Internal_Error),
+            printf ("RegularExpression::compile(): Internal error.\n"); // Never here
+            return 0;
+        case '?':
+        case '+':
+        case '*':
+            //RAISE Error, SYM(RegularExpression), SYM(No_Operand),
+            printf ("RegularExpression::compile(): ?+* follows nothing.\n");
+            return 0;
+        case '\\':
+            if (*regparse == '\0') {
+                //RAISE Error, SYM(RegularExpression), SYM(Trailing_Backslash),
+                printf ("RegularExpression::compile(): Trailing backslash.\n");
+                return 0;
+            }
+            ret = regnode(EXACTLY);
+            regc(*regparse++);
+            regc('\0');
+            *flagp |= HASWIDTH | SIMPLE;
+            break;
+        default:{
+                register int    len;
+                register char   ender;
+
+                regparse--;
+                len = int(strcspn(regparse, META));
+                if (len <= 0) {
+                    //RAISE Error, SYM(RegularExpression), SYM(Internal_Error),
+                    printf ("RegularExpression::compile(): Internal error.\n");
+                    return 0;
+                }
+                ender = *(regparse + len);
+                if (len > 1 && ISMULT(ender))
+                    len--;      // Back off clear of ?+* operand.
+                *flagp |= HASWIDTH;
+                if (len == 1)
+                    *flagp |= SIMPLE;
+                ret = regnode(EXACTLY);
+                while (len > 0) {
+                    regc(*regparse++);
+                    len--;
+                }
+                regc('\0');
+            }
+            break;
+    }
+    return (ret);
+}
+
+
+/*
+ - regnode - emit a node
+   Location.
+ */
+static char* regnode (char op) {
+    register char* ret;
+    register char* ptr;
+
+    ret = regcode;
+    if (ret == &regdummy) {
+        regsize += 3;
+        return (ret);
+    }
+
+    ptr = ret;
+    *ptr++ = op;
+    *ptr++ = '\0';              // Null "next" pointer.
+    *ptr++ = '\0';
+    regcode = ptr;
+
+    return (ret);
+}
+
+
+/*
+ - regc - emit (if appropriate) a byte of code
+ */
+static void regc (unsigned char b) {
+    if (regcode != &regdummy)
+        *regcode++ = b;
+    else
+        regsize++;
+}
+
+
+/*
+ - reginsert - insert an operator in front of already-emitted operand
+ *
+ * Means relocating the operand.
+ */
+static void reginsert (char op, char* opnd) {
+    register char* src;
+    register char* dst;
+    register char* place;
+
+    if (regcode == &regdummy) {
+        regsize += 3;
+        return;
+    }
+
+    src = regcode;
+    regcode += 3;
+    dst = regcode;
+    while (src > opnd)
+        *--dst = *--src;
+
+    place = opnd;               // Op node, where operand used to be.
+    *place++ = op;
+    *place++ = '\0';
+    *place++ = '\0';
+}
+
+
+/*
+ - regtail - set the next-pointer at the end of a node chain
+ */
+static void regtail (char* p, const char* val) {
+    register char* scan;
+    register char* temp;
+    register int   offset;
+
+    if (p == &regdummy)
+        return;
+
+    // Find last node.
+    scan = p;
+    for (;;) {
+        temp = regnext(scan);
+        if (temp == 0)
+            break;
+        scan = temp;
+    }
+
+    if (OP(scan) == BACK)
+        offset = int(scan - val);
+    else
+        offset = int(val - scan);
+    *(scan + 1) = (offset >> 8) & 0377;
+    *(scan + 2) = offset & 0377;
+}
+
+
+/*
+ - regoptail - regtail on operand of first argument; nop if operandless
+ */
+static void regoptail (char* p, const char* val) {
+    // "Operandless" and "op != BRANCH" are synonymous in practice.
+    if (p == 0 || p == &regdummy || OP(p) != BRANCH)
+        return;
+    regtail(OPERAND(p), val);
+}
+
+
+
+////////////////////////////////////////////////////////////////////////
+// 
+//  find and friends
+// 
+////////////////////////////////////////////////////////////////////////
+
+
+/*
+ * Global work variables for find().
+ */
+static const char*  reginput;   // String-input pointer.
+static const char*  regbol;     // Beginning of input, for ^ check.
+static const char* *regstartp;  // Pointer to startp array.
+static const char* *regendp;    // Ditto for endp.
+
+/*
+ * Forwards.
+ */
+static int regtry (const char*, const char* *,
+                   const char* *, const char*);
+static int regmatch (const char*);
+static int regrepeat (const char*);
+
+#ifdef DEBUG
+int          regnarrate = 0;
+void         regdump ();
+static char* regprop ();
+#endif
+
+bool RegularExpression::find (kwsys_std::string const& s) 
+{
+  return find(s.c_str());
+}
+
+
+
+// find -- Matches the regular expression to the given string.
+// Returns true if found, and sets start and end indexes accordingly.
+
+bool RegularExpression::find (const char* string) {
+    register const char* s;
+
+    this->searchstring = string;
+
+    if (!this->program)
+      {
+      return false;
+      }
+    
+    // Check validity of program.
+    if (UCHARAT(this->program) != MAGIC) {
+        //RAISE Error, SYM(RegularExpression), SYM(Internal_Error),
+        printf ("RegularExpression::find(): Compiled regular expression corrupted.\n");
+        return 0;
+    }
+    
+    // If there is a "must appear" string, look for it.
+    if (this->regmust != 0) {
+        s = string;
+        while ((s = strchr(s, this->regmust[0])) != 0) {
+            if (strncmp(s, this->regmust, this->regmlen) == 0)
+                break;          // Found it.
+            s++;
+        }
+        if (s == 0)             // Not present.
+            return (0);
+    }
+     
+    // Mark beginning of line for ^ .
+    regbol = string;
+
+    // Simplest case:  anchored match need be tried only once.
+    if (this->reganch)
+        return (regtry(string, this->startp, this->endp, this->program) != 0);
+    
+    // Messy cases:  unanchored match.
+    s = string;
+    if (this->regstart != '\0')
+        // We know what char it must start with.
+        while ((s = strchr(s, this->regstart)) != 0) {
+            if (regtry(s, this->startp, this->endp, this->program))
+                return (1);
+            s++;
+          
+        }
+    else
+        // We don't -- general case.
+        do {
+            if (regtry(s, this->startp, this->endp, this->program))
+                return (1);
+        } while (*s++ != '\0');
+    
+    // Failure.
+    return (0);
+}
+
+
+/*
+ - regtry - try match at specific point
+   0 failure, 1 success
+ */
+static int regtry (const char* string, const char* *start,
+                   const char* *end, const char* prog) {
+    register       int    i;
+    register const char* *sp1;
+    register const char* *ep;
+
+    reginput = string;
+    regstartp = start;
+    regendp = end;
+
+    sp1 = start;
+    ep = end;
+    for (i = RegularExpressionNSUBEXP; i > 0; i--) {
+        *sp1++ = 0;
+        *ep++ = 0;
+    }
+    if (regmatch(prog + 1)) {
+        start[0] = string;
+        end[0] = reginput;
+        return (1);
+    }
+    else
+        return (0);
+}
+
+
+/*
+ - regmatch - main matching routine
+ *
+ * Conceptually the strategy is simple:  check to see whether the current
+ * node matches, call self recursively to see whether the rest matches,
+ * and then act accordingly.  In practice we make some effort to avoid
+ * recursion, in particular by going through "ordinary" nodes (that don't
+ * need to know whether the rest of the match failed) by a loop instead of
+ * by recursion.
+ * 0 failure, 1 success
+ */
+static int regmatch (const char* prog) {
+    register const char* scan;  // Current node.
+             const char* next;  // Next node.
+
+    scan = prog;
+
+    while (scan != 0) {
+
+        next = regnext(scan);
+
+        switch (OP(scan)) {
+            case BOL:
+                if (reginput != regbol)
+                    return (0);
+                break;
+            case EOL:
+                if (*reginput != '\0')
+                    return (0);
+                break;
+            case ANY:
+                if (*reginput == '\0')
+                    return (0);
+                reginput++;
+                break;
+            case EXACTLY:{
+                    register int         len;
+                    register const char* opnd;
+
+                    opnd = OPERAND(scan);
+                    // Inline the first character, for speed.
+                    if (*opnd != *reginput)
+                        return (0);
+                    len = int(strlen(opnd));
+                    if (len > 1 && strncmp(opnd, reginput, len) != 0)
+                        return (0);
+                    reginput += len;
+                }
+                break;
+            case ANYOF:
+                if (*reginput == '\0' || strchr(OPERAND(scan), *reginput) == 0)
+                    return (0);
+                reginput++;
+                break;
+            case ANYBUT:
+                if (*reginput == '\0' || strchr(OPERAND(scan), *reginput) != 0)
+                    return (0);
+                reginput++;
+                break;
+            case NOTHING:
+                break;
+            case BACK:
+                break;
+            case OPEN + 1:
+            case OPEN + 2:
+            case OPEN + 3:
+            case OPEN + 4:
+            case OPEN + 5:
+            case OPEN + 6:
+            case OPEN + 7:
+            case OPEN + 8:
+            case OPEN + 9:{
+                    register       int    no;
+                    register const char* save;
+
+                    no = OP(scan) - OPEN;
+                    save = reginput;
+
+                    if (regmatch(next)) {
+
+                        //
+                        // Don't set startp if some later invocation of the
+                        // same parentheses already has. 
+                        //
+                        if (regstartp[no] == 0)
+                            regstartp[no] = save;
+                        return (1);
+                    }
+                    else
+                        return (0);
+                }
+//              break;
+            case CLOSE + 1:
+            case CLOSE + 2:
+            case CLOSE + 3:
+            case CLOSE + 4:
+            case CLOSE + 5:
+            case CLOSE + 6:
+            case CLOSE + 7:
+            case CLOSE + 8:
+            case CLOSE + 9:{
+                    register       int    no;
+                    register const char* save;
+
+                    no = OP(scan) - CLOSE;
+                    save = reginput;
+
+                    if (regmatch(next)) {
+
+                        //
+                        // Don't set endp if some later invocation of the
+                        // same parentheses already has. 
+                        //
+                        if (regendp[no] == 0)
+                            regendp[no] = save;
+                        return (1);
+                    }
+                    else
+                        return (0);
+                }
+//              break;
+            case BRANCH:{
+              
+              register const char* save;
+
+                    if (OP(next) != BRANCH)     // No choice.
+                        next = OPERAND(scan);   // Avoid recursion.
+                    else {
+                        do {
+                            save = reginput;
+                            if (regmatch(OPERAND(scan)))
+                                return (1);
+                            reginput = save;
+                            scan = regnext(scan);
+                        } while (scan != 0 && OP(scan) == BRANCH);
+                        return (0);
+                        // NOTREACHED
+                    }
+                }
+                break;
+            case STAR:
+            case PLUS:{
+              register char   nextch;
+                    register int        no;
+                    register const char* save;
+                    register int        min_no;
+
+                    //
+                    // Lookahead to avoid useless match attempts when we know
+                    // what character comes next. 
+                    //
+                    nextch = '\0';
+                    if (OP(next) == EXACTLY)
+                        nextch = *OPERAND(next);
+                    min_no = (OP(scan) == STAR) ? 0 : 1;
+                    save = reginput;
+                    no = regrepeat(OPERAND(scan));
+                    while (no >= min_no) {
+                        // If it could work, try it.
+                        if (nextch == '\0' || *reginput == nextch)
+                            if (regmatch(next))
+                                return (1);
+                        // Couldn't or didn't -- back up.
+                        no--;
+                        reginput = save + no;
+                    }
+                    return (0);
+                }
+//              break;
+            case END:
+                return (1);     // Success!
+
+            default:
+                //RAISE Error, SYM(RegularExpression), SYM(Internal_Error),
+                printf ("RegularExpression::find(): Internal error -- memory corrupted.\n");
+                return 0;
+        }
+        scan = next;
+    }
+
+    // 
+    //  We get here only if there's trouble -- normally "case END" is the
+    //  terminating point. 
+    // 
+    //RAISE Error, SYM(RegularExpression), SYM(Internal_Error),
+    printf ("RegularExpression::find(): Internal error -- corrupted pointers.\n");
+    return (0);
+}
+
+
+/*
+ - regrepeat - repeatedly match something simple, report how many
+ */
+static int regrepeat (const char* p) {
+    register       int   count = 0;
+    register const char* scan;
+    register const char* opnd;
+
+    scan = reginput;
+    opnd = OPERAND(p);
+    switch (OP(p)) {
+        case ANY:
+            count = int(strlen(scan));
+            scan += count;
+            break;
+        case EXACTLY:
+            while (*opnd == *scan) {
+                count++;
+                scan++;
+            }
+            break;
+        case ANYOF:
+            while (*scan != '\0' && strchr(opnd, *scan) != 0) {
+                count++;
+                scan++;
+            }
+            break;
+        case ANYBUT:
+            while (*scan != '\0' && strchr(opnd, *scan) == 0) {
+                count++;
+                scan++;
+            }
+            break;
+        default:                // Oh dear.  Called inappropriately.
+            //RAISE Error, SYM(RegularExpression), SYM(Internal_Error),
+            printf ("cm RegularExpression::find(): Internal error.\n");
+            return 0;
+    }
+    reginput = scan;
+    return (count);
+}
+
+
+/*
+ - regnext - dig the "next" pointer out of a node
+ */
+static const char* regnext (register const char* p) {
+    register int offset;
+
+    if (p == &regdummy)
+        return (0);
+
+    offset = NEXT(p);
+    if (offset == 0)
+        return (0);
+
+    if (OP(p) == BACK)
+        return (p - offset);
+    else
+        return (p + offset);
+}
+
+
+static char* regnext (register char* p) {
+    register int offset;
+
+    if (p == &regdummy)
+        return (0);
+
+    offset = NEXT(p);
+    if (offset == 0)
+        return (0);
+
+    if (OP(p) == BACK)
+        return (p - offset);
+    else
+        return (p + offset);
+}
+
+} // namespace KWSYS_NAMESPACE