Line data    Source code

       1             : /*
       2             :  * Utility functions for handling cvecs
       3             :  * This file is #included by regcomp.c.
       4             :  *
       5             :  * Copyright (c) 1998, 1999 Henry Spencer.  All rights reserved.
       6             :  *
       7             :  * Development of this software was funded, in part, by Cray Research Inc.,
       8             :  * UUNET Communications Services Inc., Sun Microsystems Inc., and Scriptics
       9             :  * Corporation, none of whom are responsible for the results.  The author
      10             :  * thanks all of them.
      11             :  *
      12             :  * Redistribution and use in source and binary forms -- with or without
      13             :  * modification -- are permitted for any purpose, provided that
      14             :  * redistributions in source form retain this entire copyright notice and
      15             :  * indicate the origin and nature of any modifications.
      16             :  *
      17             :  * I'd appreciate being given credit for this package in the documentation
      18             :  * of software which uses it, but that is not a requirement.
      19             :  *
      20             :  * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES,
      21             :  * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY
      22             :  * AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL
      23             :  * HENRY SPENCER BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
      24             :  * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
      25             :  * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
      26             :  * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
      27             :  * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
      28             :  * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
      29             :  * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
      30             :  *
      31             :  * src/backend/regex/regc_cvec.c
      32             :  *
      33             :  */
      34             : 
      35             : /*
      36             :  * Notes:
      37             :  * Only (selected) functions in _this_ file should treat the chr arrays
      38             :  * of a cvec as non-constant.
      39             :  */
      40             : 
      41             : /*
      42             :  * newcvec - allocate a new cvec
      43             :  */
      44             : static struct cvec *
      45         253 : newcvec(int nchrs,              /* to hold this many chrs... */
      46             :         int nranges)            /* ... and this many ranges */
      47             : {
      48         253 :     size_t      nc = (size_t) nchrs + (size_t) nranges * 2;
      49         253 :     size_t      n = sizeof(struct cvec) + nc * sizeof(chr);
      50         253 :     struct cvec *cv = (struct cvec *) MALLOC(n);
      51             : 
      52         253 :     if (cv == NULL)
      53           0 :         return NULL;
      54         253 :     cv->chrspace = nchrs;
      55         253 :     cv->chrs = (chr *) (((char *) cv) + sizeof(struct cvec));
      56         253 :     cv->ranges = cv->chrs + nchrs;
      57         253 :     cv->rangespace = nranges;
      58         253 :     return clearcvec(cv);
      59             : }
      60             : 
      61             : /*
      62             :  * clearcvec - clear a possibly-new cvec
      63             :  * Returns pointer as convenience.
      64             :  */
      65             : static struct cvec *
      66         283 : clearcvec(struct cvec *cv)
      67             : {
      68         283 :     assert(cv != NULL);
      69         283 :     cv->nchrs = 0;
      70         283 :     cv->nranges = 0;
      71         283 :     cv->cclasscode = -1;
      72         283 :     return cv;
      73             : }
      74             : 
      75             : /*
      76             :  * addchr - add a chr to a cvec
      77             :  */
      78             : static void
      79          31 : addchr(struct cvec *cv,         /* character vector */
      80             :        chr c)                   /* character to add */
      81             : {
      82          31 :     assert(cv->nchrs < cv->chrspace);
      83          31 :     cv->chrs[cv->nchrs++] = c;
      84          31 : }
      85             : 
      86             : /*
      87             :  * addrange - add a range to a cvec
      88             :  */
      89             : static void
      90          14 : addrange(struct cvec *cv,       /* character vector */
      91             :          chr from,              /* first character of range */
      92             :          chr to)                /* last character of range */
      93             : {
      94          14 :     assert(cv->nranges < cv->rangespace);
      95          14 :     cv->ranges[cv->nranges * 2] = from;
      96          14 :     cv->ranges[cv->nranges * 2 + 1] = to;
      97          14 :     cv->nranges++;
      98          14 : }
      99             : 
     100             : /*
     101             :  * getcvec - get a transient cvec, initialized to empty
     102             :  *
     103             :  * The returned cvec is valid only until the next call of getcvec, which
     104             :  * typically will recycle the space.  Callers should *not* free the cvec
     105             :  * explicitly; it will be cleaned up when the struct vars is destroyed.
     106             :  *
     107             :  * This is typically used while interpreting bracket expressions.  In that
     108             :  * usage the cvec is only needed momentarily until we build arcs from it,
     109             :  * so transientness is a convenient behavior.
     110             :  */
     111             : static struct cvec *
     112          30 : getcvec(struct vars *v,         /* context */
     113             :         int nchrs,              /* to hold this many chrs... */
     114             :         int nranges)            /* ... and this many ranges */
     115             : {
     116             :     /* recycle existing transient cvec if large enough */
     117          60 :     if (v->cv != NULL && nchrs <= v->cv->chrspace &&
     118          30 :         nranges <= v->cv->rangespace)
     119          30 :         return clearcvec(v->cv);
     120             : 
     121             :     /* nope, make a new one */
     122           0 :     if (v->cv != NULL)
     123           0 :         freecvec(v->cv);
     124           0 :     v->cv = newcvec(nchrs, nranges);
     125           0 :     if (v->cv == NULL)
     126           0 :         ERR(REG_ESPACE);
     127             : 
     128           0 :     return v->cv;
     129             : }
     130             : 
     131             : /*
     132             :  * freecvec - free a cvec
     133             :  */
     134             : static void
     135         253 : freecvec(struct cvec *cv)
     136             : {
     137         253 :     FREE(cv);
     138         253 : }