source: git/src/readval.c @ ca7261b

/* readval.c
 * Routines to read a prefix or number from the current input file
 * Copyright (C) 1991-2024 Olly Betts
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301 USA
 */

#include <config.h>

#include <limits.h>
#include <stddef.h> /* for offsetof */

#include "cavern.h"
#include "commands.h" /* For match_tok(), etc */
#include "date.h"
#include "debug.h"
#include "filename.h"
#include "message.h"
#include "readval.h"
#include "datain.h"
#include "netbits.h"
#include "osalloc.h"
#include "str.h"

#ifdef HAVE_SETJMP_H
# define LONGJMP(JB) longjmp((JB), 1)
#else
# define LONGJMP(JB) exit(1)
#endif

int root_depr_count = 0;

static prefix *
new_anon_station(void)
{
    prefix *name = osnew(prefix);
    name->pos = NULL;
    name->ident = NULL;
    name->shape = 0;
    name->stn = NULL;
    name->up = pcs->Prefix;
    name->down = NULL;
    name->filename = file.filename;
    name->line = file.line;
    name->min_export = name->max_export = 0;
    name->sflags = BIT(SFLAGS_ANON);
    /* Keep linked list of anon stations for node stats. */
    name->right = anon_list;
    anon_list = name;
    return name;
}

/* if prefix is omitted: if PFX_OPT set return NULL, otherwise use longjmp */
extern prefix *
read_prefix(unsigned pfx_flags)
{
   bool f_optional = !!(pfx_flags & PFX_OPT);
   bool fSurvey = !!(pfx_flags & PFX_SURVEY);
   bool fSuspectTypo = !!(pfx_flags & PFX_SUSPECT_TYPO);
   prefix *back_ptr, *ptr;
   char *name;
   size_t name_len = 32;
   size_t i;
   bool fNew;
   bool fImplicitPrefix = true;
   int depth = -1;
   filepos here;
   filepos fp_firstsep;

   skipblanks();
   get_pos(&here);
#ifndef NO_DEPRECATED
   if (isRoot(ch)) {
      if (!(pfx_flags & PFX_ALLOW_ROOT)) {
         compile_diagnostic(DIAG_ERR|DIAG_COL, /*ROOT is deprecated*/25);
         LONGJMP(file.jbSkipLine);
      }
      if (root_depr_count < 5) {
         compile_diagnostic(DIAG_WARN|DIAG_COL, /*ROOT is deprecated*/25);
         if (++root_depr_count == 5)
            compile_diagnostic(DIAG_INFO, /*Further uses of this deprecated feature will not be reported*/95);
      }
      nextch();
      ptr = root;
      if (!isNames(ch)) {
         if (!isSep(ch)) return ptr;
         /* Allow optional SEPARATOR after ROOT */
         get_pos(&fp_firstsep);
         nextch();
      }
      fImplicitPrefix = false;
#else
   if (0) {
#endif
   } else {
      if ((pfx_flags & PFX_ANON) &&
          (isSep(ch) || (pcs->dash_for_anon_wall_station && ch == '-'))) {
         int first_ch = ch;
         nextch();
         if (isBlank(ch) || isComm(ch) || isEol(ch)) {
            if (!isSep(first_ch))
               goto anon_wall_station;
            /* A single separator alone ('.' by default) is an anonymous
             * station which is on a point inside the passage and implies
             * the leg to it is a splay.
             */
            if (TSTBIT(pcs->flags, FLAGS_ANON_ONE_END)) {
               set_pos(&here);
               compile_diagnostic(DIAG_ERR|DIAG_WORD, /*Can't have a leg between two anonymous stations*/3);
               LONGJMP(file.jbSkipLine);
            }
            pcs->flags |= BIT(FLAGS_ANON_ONE_END) | BIT(FLAGS_IMPLICIT_SPLAY);
            return new_anon_station();
         }
         if (isSep(first_ch) && ch == first_ch) {
            nextch();
            if (isBlank(ch) || isComm(ch) || isEol(ch)) {
               /* A double separator ('..' by default) is an anonymous station
                * which is on the wall and implies the leg to it is a splay.
                */
               prefix * pfx;
anon_wall_station:
               if (TSTBIT(pcs->flags, FLAGS_ANON_ONE_END)) {
                  set_pos(&here);
                  compile_diagnostic(DIAG_ERR|DIAG_WORD, /*Can't have a leg between two anonymous stations*/3);
                  LONGJMP(file.jbSkipLine);
               }
               pcs->flags |= BIT(FLAGS_ANON_ONE_END) | BIT(FLAGS_IMPLICIT_SPLAY);
               pfx = new_anon_station();
               pfx->sflags |= BIT(SFLAGS_WALL);
               return pfx;
            }
            if (ch == first_ch) {
               nextch();
               if (isBlank(ch) || isComm(ch) || isEol(ch)) {
                  /* A triple separator ('...' by default) is an anonymous
                   * station, but otherwise not handled specially (e.g. for
                   * a single leg down an unexplored side passage to a station
                   * which isn't refindable).
                   */
                  if (TSTBIT(pcs->flags, FLAGS_ANON_ONE_END)) {
                     set_pos(&here);
                     compile_diagnostic(DIAG_ERR|DIAG_WORD, /*Can't have a leg between two anonymous stations*/3);
                     LONGJMP(file.jbSkipLine);
                  }
                  pcs->flags |= BIT(FLAGS_ANON_ONE_END);
                  return new_anon_station();
               }
            }
         }
         set_pos(&here);
      }
      ptr = pcs->Prefix;
   }

   i = 0;
   name = NULL;
   do {
      fNew = false;
      if (name == NULL) {
         /* Need a new name buffer */
         name = osmalloc(name_len);
      }
      /* i==0 iff this is the first pass */
      if (i) {
         i = 0;
         nextch();
      }
      while (isNames(ch)) {
         if (i < pcs->Truncate) {
            /* truncate name */
            name[i++] = (pcs->Case == LOWER ? tolower(ch) :
                         (pcs->Case == OFF ? ch : toupper(ch)));
            if (i >= name_len) {
               name_len = name_len + name_len;
               name = osrealloc(name, name_len);
            }
         }
         nextch();
      }
      if (isSep(ch)) {
         fImplicitPrefix = false;
         get_pos(&fp_firstsep);
      }
      if (i == 0) {
         osfree(name);
         if (!f_optional) {
            if (isEol(ch)) {
               if (fSurvey) {
                  compile_diagnostic(DIAG_ERR|DIAG_COL, /*Expecting survey name*/89);
               } else {
                  compile_diagnostic(DIAG_ERR|DIAG_COL, /*Expecting station name*/28);
               }
            } else {
               /* TRANSLATORS: Here "station" is a survey station, not a train station. */
               compile_diagnostic(DIAG_ERR|DIAG_COL, /*Character “%c” not allowed in station name (use *SET NAMES to set allowed characters)*/7, ch);
            }
            LONGJMP(file.jbSkipLine);
         }
         return (prefix *)NULL;
      }

      name[i++] = '\0';

      back_ptr = ptr;
      ptr = ptr->down;
      if (ptr == NULL) {
         /* Special case first time around at each level */
         name = osrealloc(name, i);
         ptr = osnew(prefix);
         ptr->ident = name;
         name = NULL;
         ptr->right = ptr->down = NULL;
         ptr->pos = NULL;
         ptr->shape = 0;
         ptr->stn = NULL;
         ptr->up = back_ptr;
         ptr->filename = file.filename;
         ptr->line = file.line;
         ptr->min_export = ptr->max_export = 0;
         ptr->sflags = BIT(SFLAGS_SURVEY);
         if (fSuspectTypo && !fImplicitPrefix)
            ptr->sflags |= BIT(SFLAGS_SUSPECTTYPO);
         back_ptr->down = ptr;
         fNew = true;
      } else {
         /* Use caching to speed up adding an increasing sequence to a
          * large survey */
         static prefix *cached_survey = NULL, *cached_station = NULL;
         prefix *ptrPrev = NULL;
         int cmp = 1; /* result of strcmp ( -ve for <, 0 for =, +ve for > ) */
         if (cached_survey == back_ptr) {
            cmp = strcmp(cached_station->ident, name);
            if (cmp <= 0) ptr = cached_station;
         }
         while (ptr && (cmp = strcmp(ptr->ident, name)) < 0) {
            ptrPrev = ptr;
            ptr = ptr->right;
         }
         if (cmp) {
            /* ie we got to one that was higher, or the end */
            prefix *newptr;
            name = osrealloc(name, i);
            newptr = osnew(prefix);
            newptr->ident = name;
            name = NULL;
            if (ptrPrev == NULL)
               back_ptr->down = newptr;
            else
               ptrPrev->right = newptr;
            newptr->right = ptr;
            newptr->down = NULL;
            newptr->pos = NULL;
            newptr->shape = 0;
            newptr->stn = NULL;
            newptr->up = back_ptr;
            newptr->filename = file.filename;
            newptr->line = file.line;
            newptr->min_export = newptr->max_export = 0;
            newptr->sflags = BIT(SFLAGS_SURVEY);
            if (fSuspectTypo && !fImplicitPrefix)
               newptr->sflags |= BIT(SFLAGS_SUSPECTTYPO);
            ptr = newptr;
            fNew = true;
         }
         cached_survey = back_ptr;
         cached_station = ptr;
      }
      depth++;
      f_optional = false; /* disallow after first level */
      if (isSep(ch)) {
         get_pos(&fp_firstsep);
         if (!TSTBIT(ptr->sflags, SFLAGS_SURVEY)) {
            /* TRANSLATORS: Here "station" is a survey station, not a train station.
             *
             * Here "survey" is a "cave map" rather than list of questions - it should be
             * translated to the terminology that cavers using the language would use.
             */
            compile_diagnostic(DIAG_ERR|DIAG_FROM(here), /*“%s” can’t be both a station and a survey*/27,
                               sprint_prefix(ptr));
         }
      }
   } while (isSep(ch));
   if (name) osfree(name);

   /* don't warn about a station that is referred to twice */
   if (!fNew) ptr->sflags &= ~BIT(SFLAGS_SUSPECTTYPO);

   if (fNew) {
      /* fNew means SFLAGS_SURVEY is currently set */
      SVX_ASSERT(TSTBIT(ptr->sflags, SFLAGS_SURVEY));
      if (!fSurvey) {
         ptr->sflags &= ~BIT(SFLAGS_SURVEY);
         if (TSTBIT(pcs->infer, INFER_EXPORTS)) ptr->min_export = USHRT_MAX;
      }
   } else {
      /* check that the same name isn't being used for a survey and station */
      if (fSurvey ^ TSTBIT(ptr->sflags, SFLAGS_SURVEY)) {
         /* TRANSLATORS: Here "station" is a survey station, not a train station.
          *
          * Here "survey" is a "cave map" rather than list of questions - it should be
          * translated to the terminology that cavers using the language would use.
          */
         compile_diagnostic(DIAG_ERR|DIAG_FROM(here), /*“%s” can’t be both a station and a survey*/27,
                            sprint_prefix(ptr));
      }
      if (!fSurvey && TSTBIT(pcs->infer, INFER_EXPORTS)) ptr->min_export = USHRT_MAX;
   }

   /* check the export level */
#if 0
   printf("R min %d max %d depth %d pfx %s\n",
          ptr->min_export, ptr->max_export, depth, sprint_prefix(ptr));
#endif
   if (ptr->min_export == 0 || ptr->min_export == USHRT_MAX) {
      if (depth > ptr->max_export) ptr->max_export = depth;
   } else if (ptr->max_export < depth) {
      prefix *survey = ptr;
      char *s;
      const char *p;
      int level;
      for (level = ptr->max_export + 1; level; level--) {
         survey = survey->up;
         SVX_ASSERT(survey);
      }
      s = osstrdup(sprint_prefix(survey));
      p = sprint_prefix(ptr);
      if (survey->filename) {
         compile_diagnostic_pfx(DIAG_ERR, survey,
                                /*Station “%s” not exported from survey “%s”*/26,
                                p, s);
      } else {
         compile_diagnostic(DIAG_ERR, /*Station “%s” not exported from survey “%s”*/26, p, s);
      }
      osfree(s);
#if 0
      printf(" *** pfx %s warning not exported enough depth %d "
             "ptr->max_export %d\n", sprint_prefix(ptr),
             depth, ptr->max_export);
#endif
   }
   if (!fImplicitPrefix && (pfx_flags & PFX_WARN_SEPARATOR)) {
      filepos fp_tmp;
      get_pos(&fp_tmp);
      set_pos(&fp_firstsep);
      compile_diagnostic(DIAG_WARN|DIAG_COL, /*Separator in survey name*/392);
      set_pos(&fp_tmp);
   }
   return ptr;
}

char *
read_walls_prefix(void)
{
    string name = S_INIT;
    skipblanks();
    if (!isNames(ch))
        return NULL;
    do {
        s_catchar(&name, ch);
        nextch();
    } while (isNames(ch));
    return s_steal(&name);
}

prefix *
read_walls_station(char * const walls_prefix[3], bool anon_allowed)
{
//    bool f_optional = false; //!!(pfx_flags & PFX_OPT);
//    bool fSuspectTypo = false; //!!(pfx_flags & PFX_SUSPECT_TYPO);
//    prefix *back_ptr, *ptr;
    string component = S_INIT;
//    size_t i;
//    bool fNew;
//    bool fImplicitPrefix = true;
//    int depth = -1;
//    filepos fp_firstsep;

    filepos fp;
    get_pos(&fp);

    skipblanks();
    if (anon_allowed && ch == '-') {
        // - or -- is an anonymous wall point in a shot, but in #Fix they seem
        // to just be treated as ordinary station names.
        // FIXME: Issue warning for such a useless station?
        //
        // Not yet checked, but you can presumably use - and -- as a prefix
        // (FIXME check this).
        nextch();
        int dashes = 1;
        if (ch == '-') {
            ++dashes;
            nextch();
        }
        if (!isNames(ch) && ch != ':') {
            // An anonymous station implies the leg it is on is a splay.
            if (TSTBIT(pcs->flags, FLAGS_ANON_ONE_END)) {
                set_pos(&fp);
                // Walls also rejects this case.
                compile_diagnostic(DIAG_ERR|DIAG_TOKEN, /*Can't have a leg between two anonymous stations*/3);
                LONGJMP(file.jbSkipLine);
            }
            pcs->flags |= BIT(FLAGS_ANON_ONE_END) | BIT(FLAGS_IMPLICIT_SPLAY);
            prefix *pfx = new_anon_station();
            pfx->sflags |= BIT(SFLAGS_WALL);
            return pfx;
        }
        s_catn(&component, dashes, '-');
    }

    char *w_prefix[3] = { NULL, NULL, NULL };
    int explicit_prefix_levels = 0;
    while (true) {
        while (isNames(ch)) {
            s_catchar(&component, ch);
            nextch();
        }
        //printf("component = '%s'\n", s_str(&component));
        if (ch == ':') {
            nextch();

            if (++explicit_prefix_levels > 3) {
                // FIXME Make this a proper error
                printf("too many prefix levels\n");
                s_free(&component);
                for (int i = 0; i < 3; ++i) osfree(w_prefix[i]);
                LONGJMP(file.jbSkipLine);
            }

            if (!s_empty(&component)) {
                // printf("w_prefix[%d] = '%s'\n", explicit_prefix_levels - 1, s_str(&component));
                w_prefix[explicit_prefix_levels - 1] = s_steal(&component);
            }

            continue;
        }

        // printf("explicit_prefix_levels=%d %s:%s:%s\n", explicit_prefix_levels, w_prefix[0], w_prefix[1], w_prefix[2]);

        // component is the station name itself.
        if (s_empty(&component)) {
            if (explicit_prefix_levels == 0) {
                compile_diagnostic(DIAG_ERR|DIAG_COL, /*Expecting station name*/28);
                s_free(&component);
                for (int i = 0; i < 3; ++i) osfree(w_prefix[i]);
                LONGJMP(file.jbSkipLine);
            }
            // Walls allows an empty station name if there's an explicit prefix.
            // This seems unlikely to be intended, so warn about it.
            compile_diagnostic(DIAG_WARN|DIAG_COL, /*Expecting station name*/28);
            // Use a name with a space in so it can't collide with a real
            // Walls station name.
            s_cat(&component, "empty name");
        }
        int len = s_len(&component);
        char *p = s_steal(&component);
        // Apply case treatment.
        switch (pcs->Case) {
          case LOWER:
            for (int i = 0; i < len; ++i)
                p[i] = tolower((unsigned char)p[i]);
            break;
          case UPPER:
            for (int i = 0; i < len; ++i)
                p[i] = toupper((unsigned char)p[i]);
            break;
          case OFF:
            // Avoid unhandled enum warning.
            break;
        }

        prefix *ptr = root;
        for (int i = 0; i < 4; ++i) {
            const char *name;
            int sflag = BIT(SFLAGS_SURVEY);
            if (i == 3) {
                name = p;
                // Mark stations used with explicit prefix as exported.
                sflag = explicit_prefix_levels ? BIT(SFLAGS_EXPORTED) : 0;
            } else {
                if (i < 3 - explicit_prefix_levels) {
                    name = walls_prefix[i];
                    // printf("using walls_prefix[%d] = '%s'\n", 2 - i, name);
                } else {
                    name = w_prefix[i - (3 - explicit_prefix_levels)]; // FIXME: Could steal wprefix[i].
                    // printf("using w_prefix[%d] = '%s'\n", i - (3 - explicit_prefix_levels), name);
                }

                if (name == NULL) {
                    // FIXME: This means :X::Y is treated as the same as
                    // ::X:Y but is that right?  Walls docs don't really
                    // say.  Need to test (and is they're different then
                    // probably use a character not valid in Walls station
                    // names for the empty prefix level (e.g. space or
                    // `#`).
                    //
                    // Also, does Walls allow :::X as a station and
                    // ::X:Y which would mean X is a station and survey?
                    // If so, we probably want to keep every empty level.
                    continue;
                }
            }
            prefix *back_ptr = ptr;
            ptr = ptr->down;
            if (ptr == NULL) {
                /* Special case first time around at each level */
                ptr = osnew(prefix);
                ptr->ident = (i < 3 ? osstrdup(name) : name);
                name = NULL;
                ptr->right = ptr->down = NULL;
                ptr->pos = NULL;
                ptr->shape = 0;
                ptr->stn = NULL;
                ptr->up = back_ptr;
                ptr->filename = file.filename; // FIXME: Or location of #Prefix, etc for it?
                ptr->line = file.line; // FIXME: Or location of #Prefix, etc for it?
                ptr->min_export = ptr->max_export = 0;
                ptr->sflags = sflag;
                back_ptr->down = ptr;
            } else {
                /* Use caching to speed up adding an increasing sequence to a
                 * large survey */
                static prefix *cached_survey = NULL, *cached_station = NULL;
                prefix *ptrPrev = NULL;
                int cmp = 1; /* result of strcmp ( -ve for <, 0 for =, +ve for > ) */
                if (cached_survey == back_ptr) {
                    cmp = strcmp(cached_station->ident, name);
                    if (cmp <= 0) ptr = cached_station;
                }
                while (ptr && (cmp = strcmp(ptr->ident, name))<0) {
                    ptrPrev = ptr;
                    ptr = ptr->right;
                }
                if (cmp) {
                    /* ie we got to one that was higher, or the end */
                    prefix *newptr;
                    newptr = osnew(prefix);
                    newptr->ident = (i < 3 ? osstrdup(name) : name);
                    name = NULL;
                    if (ptrPrev == NULL)
                        back_ptr->down = newptr;
                    else
                        ptrPrev->right = newptr;
                    newptr->right = ptr;
                    newptr->down = NULL;
                    newptr->pos = NULL;
                    newptr->shape = 0;
                    newptr->stn = NULL;
                    newptr->up = back_ptr;
                    newptr->filename = file.filename; // FIXME
                    newptr->line = file.line;
                    newptr->min_export = newptr->max_export = 0;
                    newptr->sflags = sflag;
                    ptr = newptr;
                } else {
                    ptr->sflags |= sflag;
                }
                cached_survey = back_ptr;
                cached_station = ptr;
            }
            if (name == p) osfree(p);
        }

        // fprint_prefix(stdout, ptr); fputnl(stdout);

        for (int i = 0; i < 3; ++i) osfree(w_prefix[i]);

        return ptr;
    }
}

/* if numeric expr is omitted: if f_optional return HUGE_REAL, else longjmp */
real
read_number(bool f_optional, bool f_unsigned)
{
   bool fPositive = true, fDigits = false;
   real n = (real)0.0;
   filepos fp;
   int ch_old;

   get_pos(&fp);
   ch_old = ch;
   if (!f_unsigned) {
      fPositive = !isMinus(ch);
      if (isSign(ch)) nextch();
   }

   while (isdigit(ch)) {
      n = n * (real)10.0 + (char)(ch - '0');
      nextch();
      fDigits = true;
   }

   if (isDecimal(ch)) {
      real mult = (real)1.0;
      nextch();
      while (isdigit(ch)) {
         mult *= (real).1;
         n += (char)(ch - '0') * mult;
         fDigits = true;
         nextch();
      }
   }

   /* !'fRead' => !fDigits so fDigits => 'fRead' */
   if (fDigits) return (fPositive ? n : -n);

   /* didn't read a valid number.  If it's optional, reset filepos & return */
   set_pos(&fp);
   if (f_optional) {
      return HUGE_REAL;
   }

   if (isOmit(ch_old)) {
      compile_diagnostic(DIAG_ERR|DIAG_COL, /*Field may not be omitted*/8);
   } else {
      compile_diagnostic_token_show(DIAG_ERR, /*Expecting numeric field, found “%s”*/9);
   }
   LONGJMP(file.jbSkipLine);
   return 0.0; /* for brain-fried compilers */
}

real
read_quadrant(bool f_optional)
{
   enum {
      POINT_N = 0,
      POINT_E = 1,
      POINT_S = 2,
      POINT_W = 3,
      POINT_NONE = -1
   };
   static const sztok pointtab[] = {
        {"E", POINT_E },
        {"N", POINT_N },
        {"S", POINT_S },
        {"W", POINT_W },
        {NULL, POINT_NONE }
   };
   static const sztok pointewtab[] = {
        {"E", POINT_E },
        {"W", POINT_W },
        {NULL, POINT_NONE }
   };
   if (f_optional && isOmit(ch)) {
      return HUGE_REAL;
   }
   const int quad = 90;
   filepos fp;
   get_pos(&fp);
   get_token_no_blanks();
   int first_point = match_tok(pointtab, TABSIZE(pointtab));
   if (first_point == POINT_NONE) {
      set_pos(&fp);
      if (isOmit(ch)) {
         compile_diagnostic(DIAG_ERR|DIAG_COL, /*Field may not be omitted*/8);
      }
      compile_diagnostic_token_show(DIAG_ERR, /*Expecting quadrant bearing, found “%s”*/483);
      LONGJMP(file.jbSkipLine);
      return 0.0; /* for brain-fried compilers */
   }
   real r = read_number(true, true);
   if (r == HUGE_REAL) {
      if (isSign(ch) || isDecimal(ch)) {
         /* Give better errors for S-0E, N+10W, N.E, etc. */
         set_pos(&fp);
         compile_diagnostic_token_show(DIAG_ERR, /*Expecting quadrant bearing, found “%s”*/483);
         LONGJMP(file.jbSkipLine);
         return 0.0; /* for brain-fried compilers */
      }
      /* N, S, E or W. */
      return first_point * quad;
   }
   if (first_point == POINT_E || first_point == POINT_W) {
      set_pos(&fp);
      compile_diagnostic_token_show(DIAG_ERR, /*Expecting quadrant bearing, found “%s”*/483);
      LONGJMP(file.jbSkipLine);
      return 0.0; /* for brain-fried compilers */
   }

   get_token_no_blanks();
   int second_point = match_tok(pointewtab, TABSIZE(pointewtab));
   if (second_point == POINT_NONE) {
      set_pos(&fp);
      compile_diagnostic_token_show(DIAG_ERR, /*Expecting quadrant bearing, found “%s”*/483);
      LONGJMP(file.jbSkipLine);
      return 0.0; /* for brain-fried compilers */
   }

   if (r > quad) {
      set_pos(&fp);
      compile_diagnostic_token_show(DIAG_ERR|DIAG_COL, /*Suspicious compass reading*/59);
      LONGJMP(file.jbSkipLine);
      return 0.0; /* for brain-fried compilers */
   }

   if (first_point == POINT_N) {
      if (second_point == POINT_W) {
         r = quad * 4 - r;
      }
   } else {
      if (second_point == POINT_W) {
         r += quad * 2;
      } else {
         r = quad * 2 - r;
      }
   }
   return r;
}

extern real
read_numeric(bool f_optional)
{
   skipblanks();
   return read_number(f_optional, false);
}

extern real
read_numeric_multi(bool f_optional, bool f_quadrants, int *p_n_readings)
{
   size_t n_readings = 0;
   real tot = (real)0.0;

   skipblanks();
   if (!isOpen(ch)) {
      real r = 0;
      if (!f_quadrants)
          r = read_number(f_optional, false);
      else
          r = read_quadrant(f_optional);
      if (p_n_readings) *p_n_readings = (r == HUGE_REAL ? 0 : 1);
      return r;
   }
   nextch();

   skipblanks();
   do {
      if (!f_quadrants)
         tot += read_number(false, false);
      else
         tot += read_quadrant(false);
      ++n_readings;
      skipblanks();
   } while (!isClose(ch));
   nextch();

   if (p_n_readings) *p_n_readings = n_readings;
   /* FIXME: special averaging for bearings ... */
   /* And for percentage gradient */
   return tot / n_readings;
}

/* read numeric expr or omit (return HUGE_REAL); else longjmp */
extern real
read_bearing_multi_or_omit(bool f_quadrants, int *p_n_readings)
{
   real v;
   v = read_numeric_multi(true, f_quadrants, p_n_readings);
   if (v == HUGE_REAL) {
      if (!isOmit(ch)) {
         compile_diagnostic_token_show(DIAG_ERR, /*Expecting numeric field, found “%s”*/9);
         LONGJMP(file.jbSkipLine);
         return 0.0; /* for brain-fried compilers */
      }
      nextch();
   }
   return v;
}

/* Don't skip blanks, variable error code */
static unsigned int
read_uint_internal(int errmsg, const filepos *fp)
{
   unsigned int n = 0;
   if (!isdigit(ch)) {
      if (fp) set_pos(fp);
      compile_diagnostic_token_show(DIAG_ERR, errmsg);
      LONGJMP(file.jbSkipLine);
   }
   while (isdigit(ch)) {
      n = n * 10 + (char)(ch - '0');
      nextch();
   }
   return n;
}

extern unsigned int
read_uint(void)
{
   skipblanks();
   return read_uint_internal(/*Expecting numeric field, found “%s”*/9, NULL);
}

extern int
read_int(int min_val, int max_val)
{
    skipblanks();
    unsigned n = 0;
    filepos fp;

    get_pos(&fp);
    bool negated = isMinus(ch);
    unsigned limit;
    if (negated) {
        limit = (unsigned)(min_val == INT_MIN ? INT_MIN : -min_val);
    } else {
        limit = (unsigned)max_val;
    }
    if (isSign(ch)) nextch();

    if (!isdigit(ch)) {
bad_value:
        set_pos(&fp);
        /* TRANSLATORS: The first %d will be replaced by the (inclusive) lower
         * bound and the second by the (inclusive) upper bound, for example:
         * Expecting integer in range -60 to 60
         */
        compile_diagnostic(DIAG_ERR|DIAG_NUM, /*Expecting integer in range %d to %d*/489);
        LONGJMP(file.jbSkipLine);
    }

    while (isdigit(ch)) {
        unsigned old_n = n;
        n = n * 10 + (char)(ch - '0');
        if (n > limit || n < old_n) {
            goto bad_value;
        }
        nextch();
    }
    if (isDecimal(ch)) goto bad_value;

    if (negated) {
        if (n > (unsigned)INT_MAX) {
            // Avoid unportable casting.
            return INT_MIN;
        }
        return -(int)n;
    }
    return (int)n;
}

extern void
read_string(string *pstr)
{
   s_clear(pstr);

   skipblanks();
   if (ch == '\"') {
      /* String quoted in "" */
      nextch();
      while (1) {
         if (isEol(ch)) {
            compile_diagnostic(DIAG_ERR|DIAG_COL, /*Missing \"*/69);
            LONGJMP(file.jbSkipLine);
         }

         if (ch == '\"') break;

         s_catchar(pstr, ch);
         nextch();
      }
      nextch();
   } else {
      /* Unquoted string */
      while (1) {
         if (isEol(ch) || isComm(ch)) {
            if (s_empty(pstr)) {
               compile_diagnostic(DIAG_ERR|DIAG_COL, /*Expecting string field*/121);
               LONGJMP(file.jbSkipLine);
            }
            return;
         }

         if (isBlank(ch)) break;

         s_catchar(pstr, ch);
         nextch();
      }
   }
}

extern void
read_date(int *py, int *pm, int *pd)
{
   unsigned int y = 0, m = 0, d = 0;
   filepos fp_date;

   skipblanks();

   get_pos(&fp_date);
   y = read_uint_internal(/*Expecting date, found “%s”*/198, &fp_date);
   /* Two digit year is 19xx. */
   if (y < 100) {
      filepos fp_save;
      get_pos(&fp_save);
      y += 1900;
      set_pos(&fp_date);
      /* TRANSLATORS: %d will be replaced by the assumed year, e.g. 1918 */
      compile_diagnostic(DIAG_WARN|DIAG_UINT, /*Assuming 2 digit year is %d*/76, y);
      set_pos(&fp_save);
   }
   if (y < 1900 || y > 2078) {
      set_pos(&fp_date);
      compile_diagnostic(DIAG_WARN|DIAG_UINT, /*Invalid year (< 1900 or > 2078)*/58);
      LONGJMP(file.jbSkipLine);
      return; /* for brain-fried compilers */
   }
   if (ch == '.') {
      filepos fp;
      nextch();
      get_pos(&fp);
      m = read_uint_internal(/*Expecting date, found “%s”*/198, &fp_date);
      if (m < 1 || m > 12) {
         set_pos(&fp);
         compile_diagnostic(DIAG_WARN|DIAG_UINT, /*Invalid month*/86);
         LONGJMP(file.jbSkipLine);
         return; /* for brain-fried compilers */
      }
      if (ch == '.') {
         nextch();
         get_pos(&fp);
         d = read_uint_internal(/*Expecting date, found “%s”*/198, &fp_date);
         if (d < 1 || d > last_day(y, m)) {
            set_pos(&fp);
            /* TRANSLATORS: e.g. 31st of April, or 32nd of any month */
            compile_diagnostic(DIAG_WARN|DIAG_UINT, /*Invalid day of the month*/87);
            LONGJMP(file.jbSkipLine);
            return; /* for brain-fried compilers */
         }
      }
   }
   if (py) *py = y;
   if (pm) *pm = m;
   if (pd) *pd = d;
}

extern void
read_walls_srv_date(int *py, int *pm, int *pd)
{
    skipblanks();

    filepos fp_date;
    get_pos(&fp_date);
    unsigned y = read_uint_internal(/*Expecting date, found “%s”*/198, &fp_date);
    int separator = -2;
    if (ch == '-' || ch == '/') {
        separator = ch;
        nextch();
    }
    filepos fp_month;
    get_pos(&fp_month);
    unsigned m = read_uint_internal(/*Expecting date, found “%s”*/198, &fp_date);
    if (ch == separator) {
        nextch();
    }
    filepos fp_day;
    get_pos(&fp_day);
    unsigned d = read_uint_internal(/*Expecting date, found “%s”*/198, &fp_date);

    filepos fp_year;
    if (y < 100) {
        // Walls recommends ISO 8601 date format (yyyy-mm-dd and seemingly the
        // non-standard variant yyyy/mm/dd), but also accepts "some date formats
        // common in the U.S. (mm/dd/yy, mm-dd-yyyy, etc.)"
        unsigned tmp = y;
        y = d;
        fp_year = fp_day;
        d = m;
        fp_day = fp_month;
        m = tmp;
        fp_month = fp_date;

        if (y < 100) {
            // FIXME: Are all 2 digit years 19xx?
            y += 1900;

            filepos fp_save;
            get_pos(&fp_save);
            set_pos(&fp_year);
            /* TRANSLATORS: %d will be replaced by the assumed year, e.g. 1918 */
            compile_diagnostic(DIAG_WARN|DIAG_UINT, /*Assuming 2 digit year is %d*/76, y);
            set_pos(&fp_save);
        }
    } else {
        if (y < 1900 || y > 2078) {
            set_pos(&fp_date);
            compile_diagnostic(DIAG_WARN|DIAG_UINT, /*Invalid year (< 1900 or > 2078)*/58);
            LONGJMP(file.jbSkipLine);
            return; /* for brain-fried compilers */
        }
        fp_year = fp_date;
    }

    if (m < 1 || m > 12) {
        set_pos(&fp_month);
        compile_diagnostic(DIAG_WARN|DIAG_UINT, /*Invalid month*/86);
        LONGJMP(file.jbSkipLine);
        return; /* for brain-fried compilers */
    }

    if (d < 1 || d > last_day(y, m)) {
        set_pos(&fp_day);
        /* TRANSLATORS: e.g. 31st of April, or 32nd of any month */
        compile_diagnostic(DIAG_WARN|DIAG_UINT, /*Invalid day of the month*/87);
        LONGJMP(file.jbSkipLine);
        return; /* for brain-fried compilers */
    }

    if (py) *py = y;
    if (pm) *pm = m;
    if (pd) *pd = d;
}