eqn/input.c

   1 #include "e.h"
   2 #include "y.tab.h"
   3 #include <ctype.h>
   4 #include <errno.h>
   5
   6 Infile  infile[10];
   7 Infile  *curfile = infile;
   8
   9 #define MAXSRC  50
  10 Src     src[MAXSRC];    /* input source stack */
  11 Src     *srcp   = src;
  12
  13 extern int getarg(char *);
  14 extern  void eprint(void);
  15
  16 void pushsrc(int type, char *ptr)       /* new input source */
  17 {
  18         if (++srcp >= src + MAXSRC)
  19                 ERROR "inputs nested too deep" FATAL;
  20         srcp->type = type;
  21         srcp->sp = ptr;
  22         if (dbg > 1) {
  23                 printf("\n%3d ", srcp - src);
  24                 switch (srcp->type) {
  25                 case File:
  26                         printf("push file %s\n", ((Infile *)ptr)->fname);
  27                         break;
  28                 case Macro:
  29                         printf("push macro <%s>\n", ptr);
  30                         break;
  31                 case Char:
  32                         printf("push char <%c>\n", *ptr);
  33                         break;
  34                 case String:
  35                         printf("push string <%s>\n", ptr);
  36                         break;
  37                 case Free:
  38                         printf("push free <%s>\n", ptr);
  39                         break;
  40                 default:
  41                         ERROR "pushed bad type %d\n", srcp->type FATAL;
  42                 }
  43         }
  44 }
  45
  46 void popsrc(void)       /* restore an old one */
  47 {
  48         if (srcp <= src)
  49                 ERROR "too many inputs popped" FATAL;
  50         if (dbg > 1) {
  51                 printf("%3d ", srcp - src);
  52                 switch (srcp->type) {
  53                 case File:
  54                         printf("pop file\n");
  55                         break;
  56                 case Macro:
  57                         printf("pop macro\n");
  58                         break;
  59                 case Char:
  60                         printf("pop char <%c>\n", *srcp->sp);
  61                         break;
  62                 case String:
  63                         printf("pop string\n");
  64                         break;
  65                 case Free:
  66                         printf("pop free\n");
  67                         break;
  68                 default:
  69                         ERROR "pop weird input %d\n", srcp->type FATAL;
  70                 }
  71         }
  72         srcp--;
  73 }
  74
  75 Arg     args[10];       /* argument frames */
  76 Arg     *argfp = args;  /* frame pointer */
  77 int     argcnt;         /* number of arguments seen so far */
  78
  79 void dodef(tbl *stp)    /* collect args and switch input to defn */
  80 {
  81         int i, len;
  82         char *p;
  83         Arg *ap;
  84
  85         ap = argfp+1;
  86         if (ap >= args+10)
  87                 ERROR "more than arguments\n" FATAL;
  88         argcnt = 0;
  89         if (input() != '(')
  90                 ERROR "disaster in dodef\n"FATAL;
  91         if (ap->argval == 0)
  92                 ap->argval = malloc(1000);
  93         for (p = ap->argval; (len = getarg(p)) != -1; p += len) {
  94                 ap->argstk[argcnt++] = p;
  95                 if (input() == ')')
  96                         break;
  97         }
  98         for (i = argcnt; i < MAXARGS; i++)
  99                 ap->argstk[i] = "";
 100         if (dbg)
 101                 for (i = 0; i < argcnt; i++)
 102                         printf("arg %d.%d = <%s>\n", ap-args, i+1, ap->argstk[i]);
 103         argfp = ap;
 104         pushsrc(Macro, stp->cval);
 105 }
 106
 107 getarg(char *p) /* pick up single argument, store in p, return length */
 108 {
 109         int n, c, npar;
 110
 111         n = npar = 0;
 112         for ( ;; ) {
 113                 c = input();
 114                 if (c == EOF)
 115                         ERROR "end of file in getarg!\n" FATAL;
 116                 if (npar == 0 && (c == ',' || c == ')'))
 117                         break;
 118                 if (c == '"')   /* copy quoted stuff intact */
 119                         do {
 120                                 *p++ = c;
 121                                 n++;
 122                         } while ((c = input()) != '"' && c != EOF);
 123                 else if (c == '(')
 124                         npar++;
 125                 else if (c == ')')
 126                         npar--;
 127                 n++;
 128                 *p++ = c;
 129         }
 130         *p = 0;
 131         unput(c);
 132         return(n + 1);
 133 }
 134
 135 #define PBSIZE  2000
 136 char    pbuf[PBSIZE];           /* pushback buffer */
 137 char    *pb     = pbuf-1;       /* next pushed back character */
 138
 139 char    ebuf[200];              /* collect input here for error reporting */
 140 char    *ep     = ebuf;
 141
 142 input(void)
 143 {
 144         register int c = 0;
 145
 146   loop:
 147         switch (srcp->type) {
 148         case File:
 149                 c = getc(curfile->fin);
 150                 if (c == EOF) {
 151                         if (curfile == infile)
 152                                 break;
 153                         if (curfile->fin != stdin) {
 154                                 fclose(curfile->fin);
 155                                 free(curfile->fname);   /* assumes allocated */
 156                         }
 157                         curfile--;
 158                         printf(".lf %d %s\n", curfile->lineno, curfile->fname);
 159                         popsrc();
 160                         goto loop;
 161                 }
 162                 if (c == '\n')
 163                         curfile->lineno++;
 164                 break;
 165         case Char:
 166                 if (pb >= pbuf) {
 167                         c = *pb--;
 168                         popsrc();
 169                         break;
 170                 } else {        /* can't happen? */
 171                         popsrc();
 172                         goto loop;
 173                 }
 174         case String:
 175                 c = *srcp->sp++;
 176                 if (c == '\0') {
 177                         popsrc();
 178                         goto loop;
 179                 } else {
 180                         if (*srcp->sp == '\0')  /* empty, so pop */
 181                                 popsrc();
 182                         break;
 183                 }
 184         case Macro:
 185                 c = *srcp->sp++;
 186                 if (c == '\0') {
 187                         if (--argfp < args)
 188                                 ERROR "argfp underflow" FATAL;
 189                         popsrc();
 190                         goto loop;
 191                 } else if (c == '$' && isdigit(*srcp->sp)) {
 192                         int n = 0;
 193                         while (isdigit(*srcp->sp))
 194                                 n = 10 * n + *srcp->sp++ - '0';
 195                         if (n > 0 && n <= MAXARGS)
 196                                 pushsrc(String, argfp->argstk[n-1]);
 197                         goto loop;
 198                 }
 199                 break;
 200         case Free:      /* free string */
 201                 free(srcp->sp);
 202                 popsrc();
 203                 goto loop;
 204         }
 205         if (ep >= ebuf + sizeof ebuf)
 206                 ep = ebuf;
 207         *ep++ = c;
 208         return c;
 209 }
 210
 211
 212 unput(int c)
 213 {
 214         if (++pb >= pbuf + sizeof pbuf)
 215                 ERROR "pushback overflow\n"FATAL;
 216         if (--ep < ebuf)
 217                 ep = ebuf + sizeof(ebuf) - 1;
 218         *pb = c;
 219         pushsrc(Char, pb);
 220         return c;
 221 }
 222
 223 void pbstr(char *s)
 224 {
 225         pushsrc(String, s);
 226 }
 227
 228 void error(int die, char *s)
 229 {
 230         extern char *cmdname;
 231
 232         if (synerr)
 233                 return;
 234         fprintf(stderr, "%s: ", cmdname);
 235         fprintf(stderr, s);
 236         if (errno > 0)
 237                 perror("???");
 238         if (curfile->fin)
 239                 fprintf(stderr, " near %s:%d",
 240                         curfile->fname, curfile->lineno+1);
 241         fprintf(stderr, "\n");
 242         eprint();
 243         synerr = 1;
 244         errno = 0;
 245         if (die) {
 246                 if (dbg)
 247                         abort();
 248                 else
 249                         exit(1);
 250         }
 251 }
 252
 253 void yyerror(char *s)
 254 {
 255         error(0, s);    /* temporary */
 256 }
 257
 258 char errbuf[200];
 259
 260 void eprint(void)       /* try to print context around error */
 261 {
 262         char *p, *q;
 263
 264         if (ep == ebuf)
 265                 return;                         /* no context */
 266         p = ep - 1;
 267         if (p > ebuf && *p == '\n')
 268                 p--;
 269         for ( ; p >= ebuf && *p != '\n'; p--)
 270                 ;
 271         while (*p == '\n')
 272                 p++;
 273         fprintf(stderr, " context is\n\t");
 274         for (q=ep-1; q>=p && *q!=' ' && *q!='\t' && *q!='\n'; q--)
 275                 ;
 276         while (p < q)
 277                 putc(*p++, stderr);
 278         fprintf(stderr, " >>> ");
 279         while (p < ep)
 280                 putc(*p++, stderr);
 281         fprintf(stderr, " <<< ");
 282         while (pb >= pbuf)
 283                 putc(*pb--, stderr);
 284         if (curfile->fin)
 285                 fgets(ebuf, sizeof ebuf, curfile->fin);
 286         fprintf(stderr, "%s", ebuf);
 287         pbstr("\n.EN\n");       /* safety first */
 288         ep = ebuf;
 289 }