git.distorted.org.uk Git - u/mdw/catacomb/blob - math/qdparse.c

   1 /* -*-c-*-
   2  *
   3  * Quick-and-dirty parser
   4  *
   5  * (c) 2004 Straylight/Edgeware
   6  */
   7
   8 /*----- Licensing notice --------------------------------------------------*
   9  *
  10  * This file is part of Catacomb.
  11  *
  12  * Catacomb is free software; you can redistribute it and/or modify
  13  * it under the terms of the GNU Library General Public License as
  14  * published by the Free Software Foundation; either version 2 of the
  15  * License, or (at your option) any later version.
  16  *
  17  * Catacomb is distributed in the hope that it will be useful,
  18  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  19  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  20  * GNU Library General Public License for more details.
  21  *
  22  * You should have received a copy of the GNU Library General Public
  23  * License along with Catacomb; if not, write to the Free
  24  * Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
  25  * MA 02111-1307, USA.
  26  */
  27
  28 /*----- Header files ------------------------------------------------------*/
  29
  30 #include <ctype.h>
  31 #include <string.h>
  32
  33 #include "qdparse.h"
  34
  35 /*----- Main code ---------------------------------------------------------*/
  36
  37 /* --- @qd_skipspc@ --- *
  38  *
  39  * Arguments:   @qd_parse *qd@ = context
  40  *
  41  * Returns:     ---
  42  *
  43  * Use:         Skips spaces in the string.  No errors.
  44  */
  45
  46 void qd_skipspc(qd_parse *qd)
  47 {
  48   while (isspace((unsigned char)*qd->p))
  49     qd->p++;
  50 }
  51
  52 /* --- @qd_delim@ --- *
  53  *
  54  * Arguments:   @qd_parse *qd@ = context
  55  *              @int ch@ = character to compare with
  56  *
  57  * Returns:     Nonzero if it was, zero if it wasn't.
  58  *
  59  * Use:         Checks the next (non-whitespace) character is what we
  60  *              expect.  If it is, the character is eaten; otherwise it's no
  61  *              big deal.
  62  */
  63
  64 int qd_delim(qd_parse *qd, int ch)
  65 {
  66   qd_skipspc(qd);
  67   if (*qd->p != ch)
  68     return (0);
  69   qd->p++;
  70   return (1);
  71 }
  72
  73 /* --- @qd_enum@ --- *
  74  *
  75  * Arguments:   @qd_parse *qd@ = context
  76  *              @const char *e@ = list of enum strings, space separated
  77  *
  78  * Returns:     Index of the string matched, or @-1@.
  79  *
  80  * Use:         Matches a keyword.
  81  */
  82
  83 int qd_enum(qd_parse *qd, const char *e)
  84 {
  85   size_t n;
  86   int i = 0;
  87
  88   qd_skipspc(qd);
  89   for (;;) {
  90     e += strspn(e, ", ");
  91     if (!*e) break;
  92     n = strcspn(e, ", ");
  93     if (strncmp(qd->p, e, n) == 0 && !isalnum((unsigned char)qd->p[n])) {
  94       qd->p += n;
  95       return (i);
  96     }
  97     i++; e += n;
  98   }
  99   qd->e = "unrecognized keyword";
 100   return (-1);
 101 }
 102
 103 /* --- @qd_getmp@ --- *
 104  *
 105  * Arguments:   @qd_parse *qd@ = context
 106  *
 107  * Returns:     The integer extracted, or null.
 108  *
 109  * Use:         Parses a multiprecision integer from a string.
 110  */
 111
 112 mp *qd_getmp(qd_parse *qd)
 113 {
 114   char *q;
 115   mp *m;
 116
 117   qd_skipspc(qd);
 118   m = mp_readstring(MP_NEW, qd->p, &q, 0);
 119   if (m && !isalnum((unsigned char)*q))
 120     qd->p = q;
 121   else {
 122     mp_drop(m);
 123     qd->e = "bad number";
 124   }
 125   return (m);
 126 }
 127
 128 /* --- @qd_eofp@ --- *
 129  *
 130  * Arguments:   @qd_parse *qd@ = context
 131  *
 132  * Returns:     Nonzero if at EOF, zero otherwise.
 133  */
 134
 135 int qd_eofp(qd_parse *qd)
 136 {
 137   qd_skipspc(qd);
 138   return (!*qd->p);
 139 }
 140
 141 /*----- That's all, folks -------------------------------------------------*/