map.c

   1 /* mapping register/macro names to indices */
   2 #include <stdio.h>
   3 #include <string.h>
   4 #include "roff.h"
   5
   6 #define MAPBEG          256     /* the entries reserved for .x names */
   7
   8 /* register, macro, or environments names */
   9 static char keys[NREGS][GNLEN];
  10 static int nkeys = 1;
  11 /* per starting character name lists */
  12 static int key_head[256];
  13 static int key_next[NREGS];
  14
  15 /* return the index of s in keys[]; insert it if not in keys[] */
  16 static int key_get(char *s)
  17 {
  18         int head = (unsigned char) s[0];
  19         int i = key_head[head];
  20         if (*s == '\0')
  21                 return 0;
  22         while (i > 0) {
  23                 if (keys[i][1] == s[1] && !strcmp(keys[i], s))
  24                         return i;
  25                 i = key_next[i];
  26         }
  27         if (nkeys >= NREGS - MAPBEG)
  28                 errdie("neatroff: out of register names (NREGS)\n");
  29         i = nkeys++;
  30         strcpy(keys[i], s);
  31         key_next[i] = key_head[head];
  32         key_head[head] = i;
  33         return i;
  34 }
  35
  36 /* map register names to [0..NREGS] */
  37 int map(char *s)
  38 {
  39         if (s[0] == '.' && s[1] && !s[2])       /* ".x" is mapped to 'x' */
  40                 return (unsigned char) s[1];
  41         return MAPBEG + key_get(s);
  42 }
  43
  44 /* return the name mapped to id; returns a static buffer */
  45 char *map_name(int id)
  46 {
  47         static char map_buf[NMLEN];
  48         if (id >= MAPBEG)
  49                 return keys[id - MAPBEG];
  50         map_buf[0] = '.';
  51         map_buf[1] = id;
  52         map_buf[2] = '\0';
  53         return map_buf;
  54 }