cp.c

   1 #include <stdio.h>
   2 #include <stdlib.h>
   3 #include "xroff.h"
   4
   5 #define CPBUF           4
   6
   7 static int cp_buf[CPBUF];       /* pushed character stack */
   8 static int cp_backed;           /* number of pushed characters */
   9 static int cp_nblk;             /* input block depth (text in \{ and \}) */
  10 static int cp_sblk[NIES];       /* skip \} escape at this depth, if set */
  11
  12 static int regid(void)
  13 {
  14         int c1;
  15         int c2 = 0;
  16         c1 = cp_next();
  17         if (c1 == '(') {
  18                 c1 = cp_next();
  19                 c2 = cp_next();
  20         }
  21         return REG(c1, c2);
  22 }
  23
  24 static void cp_num(void)
  25 {
  26         int id;
  27         int c = cp_next();
  28         if (c != '-' && c != '+')
  29                 cp_back(c);
  30         id = regid();
  31         if (c == '-' || c == '+')
  32                 num_get(id, c == '+' ? 1 : -1);
  33         if (num_str(id))
  34                 in_push(num_str(id), NULL);
  35 }
  36
  37 static void cp_str(void)
  38 {
  39         char *buf = str_get(regid());
  40         if (buf)
  41                 in_push(buf, NULL);
  42 }
  43
  44 static void cp_arg(void)
  45 {
  46         int c;
  47         char *arg = NULL;
  48         c = cp_next();
  49         if (c >= '1' && c <= '9')
  50                 arg = in_arg(c - '0');
  51         if (arg)
  52                 in_push(arg, NULL);
  53 }
  54
  55 static int cp_raw(void)
  56 {
  57         int c;
  58         if (cp_backed)
  59                 return cp_buf[--cp_backed];
  60         c = in_next();
  61         if (c == '\\') {
  62                 c = in_next();
  63                 if (c == '\n')
  64                         return in_next();
  65                 if (c == '.')
  66                         return '.';
  67                 if (c == '{' && cp_nblk < LEN(cp_sblk))
  68                         cp_sblk[cp_nblk++] = 0;
  69                 if (c == '}' && cp_nblk > 0)
  70                         if (cp_sblk[--cp_nblk])
  71                                 return cp_raw();
  72                 cp_back(c);
  73                 return '\\';
  74         }
  75         return c;
  76 }
  77
  78 int cp_next(void)
  79 {
  80         int c;
  81         if (cp_backed)
  82                 return cp_buf[--cp_backed];
  83         c = cp_raw();
  84         if (c == '\\') {
  85                 c = cp_raw();
  86                 if (c == '"') {
  87                         while (c >= 0 && c != '\n')
  88                                 c = cp_raw();
  89                 } else if (c == 'n') {
  90                         cp_num();
  91                         c = cp_raw();
  92                 } else if (c == '*') {
  93                         cp_str();
  94                         c = cp_raw();
  95                 } else if (c == '$') {
  96                         cp_arg();
  97                         c = cp_raw();
  98                 } else {
  99                         cp_back(c);
 100                         c = '\\';
 101                 }
 102         }
 103         return c;
 104 }
 105
 106 void cp_back(int c)
 107 {
 108         if (cp_backed < CPBUF)
 109                 cp_buf[cp_backed++] = c;
 110 }
 111
 112 static int cp_top(void)
 113 {
 114         return cp_backed ? cp_buf[cp_backed - 1] : -1;
 115 }
 116
 117 void cp_blk(int skip)
 118 {
 119         int c;
 120         int nblk = cp_nblk;
 121         do {
 122                 c = cp_raw();
 123         } while (c == ' ' || c == '\t');
 124         if (c == '\\' && cp_top() == '{') {     /* a troff \{ \} block */
 125                 if (skip) {
 126                         while (skip && cp_nblk > nblk && c >= 0)
 127                                 c = cp_raw();
 128                 } else {
 129                         cp_sblk[nblk] = 1;
 130                         cp_raw();
 131                 }
 132         } else {
 133                 if (!skip)
 134                         cp_back(c);
 135         }
 136         while (skip && c != '\n')       /* skip until the end of the line */
 137                 c = cp_raw();
 138 }