src/tparam.c

   1 /* Merge parameters into a termcap entry string.
   2    Copyright (C) 1985, 1987, 1993, 1995, 2000-2008, 2013-2017 Free
   3    Software Foundation, Inc.
   4
   5 This program is free software; you can redistribute it and/or modify
   6 it under the terms of the GNU General Public License as published by
   7 the Free Software Foundation; either version 2, or (at your option)
   8 any later version.
   9
  10 This program is distributed in the hope that it will be useful,
  11 but WITHOUT ANY WARRANTY; without even the implied warranty of
  12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13 GNU General Public License for more details.
  14
  15 You should have received a copy of the GNU General Public License
  16 along with this program.  If not, see <https://www.gnu.org/licenses/>.  */
  17
  18 /* Emacs config.h may rename various library functions such as malloc.  */
  19 #include <config.h>
  20
  21 #include "lisp.h"               /* for xmalloc */
  22 #include "tparam.h"
  23 \f
  24 /* Assuming STRING is the value of a termcap string entry
  25    containing `%' constructs to expand parameters,
  26    merge in parameter values and store result in block OUTSTRING points to.
  27    LEN is the length of OUTSTRING.  If more space is needed,
  28    a block is allocated with `malloc'.
  29
  30    The value returned is the address of the resulting string.
  31    This may be OUTSTRING or may be the address of a block got with `malloc'.
  32    In the latter case, the caller must free the block.
  33
  34    The fourth and following args to tparam serve as the parameter values.  */
  35
  36 static char *tparam1 (char const *string, char *outstring, int len,
  37                       char *up, char *left, int *argp);
  38
  39 char *
  40 tparam (const char *string, char *outstring, int len,
  41         int arg0, int arg1, int arg2, int arg3)
  42 {
  43   int arg[4];
  44
  45   arg[0] = arg0;
  46   arg[1] = arg1;
  47   arg[2] = arg2;
  48   arg[3] = arg3;
  49   return tparam1 (string, outstring, len, NULL, NULL, arg);
  50 }
  51
  52 char *BC;
  53 char *UP;
  54
  55 static char tgoto_buf[50];
  56
  57 char *
  58 tgoto (const char *cm, int hpos, int vpos)
  59 {
  60   int args[2];
  61   if (!cm)
  62     return NULL;
  63   args[0] = vpos;
  64   args[1] = hpos;
  65   return tparam1 (cm, tgoto_buf, 50, UP, BC, args);
  66 }
  67
  68 static char *
  69 tparam1 (const char *string, char *outstring, int len,
  70          char *up, char *left, register int *argp)
  71 {
  72   register int c;
  73   register const char *p = string;
  74   register char *op = outstring;
  75   char *outend;
  76   char *new = 0;
  77   ptrdiff_t outlen = 0;
  78
  79   register int tem;
  80   int *old_argp = argp;                 /* can move */
  81   int *fixed_argp = argp;               /* never moves */
  82   bool explicit_param_p = false;        /* set by %p */
  83   ptrdiff_t doleft = 0;
  84   ptrdiff_t doup = 0;
  85   ptrdiff_t append_len = 0;
  86
  87   outend = outstring + len;
  88
  89   while (true)
  90     {
  91       /* If the buffer might be too short, make it bigger.  */
  92       while (outend - op - append_len <= 5)
  93         {
  94           ptrdiff_t offset = op - outstring;
  95
  96           if (outlen == 0)
  97             {
  98               outlen = len + 40;
  99               new = xmalloc (outlen);
 100               memcpy (new, outstring, offset);
 101             }
 102           else
 103             {
 104               new = xpalloc (outstring, &outlen, 1, -1, 1);
 105             }
 106
 107           op = new + offset;
 108           outend = new + outlen;
 109           outstring = new;
 110         }
 111       c = *p++;
 112       if (!c)
 113         break;
 114       if (c == '%')
 115         {
 116           c = *p++;
 117           if (explicit_param_p)
 118             explicit_param_p = false;
 119           else
 120             tem = *argp;
 121           switch (c)
 122             {
 123             case 'd':           /* %d means output in decimal.  */
 124               if (tem < 10)
 125                 goto onedigit;
 126               if (tem < 100)
 127                 goto twodigit;
 128               FALLTHROUGH;
 129             case '3':           /* %3 means output in decimal, 3 digits.  */
 130               if (tem > 999)
 131                 {
 132                   *op++ = tem / 1000 + '0';
 133                   tem %= 1000;
 134                 }
 135               *op++ = tem / 100 + '0';
 136               FALLTHROUGH;
 137             case '2':           /* %2 means output in decimal, 2 digits.  */
 138             twodigit:
 139               tem %= 100;
 140               *op++ = tem / 10 + '0';
 141             onedigit:
 142               *op++ = tem % 10 + '0';
 143               argp++;
 144               break;
 145
 146             case 'p':           /* %pN means use param N for next subst.  */
 147               tem = fixed_argp[(*p++) - '1'];
 148               explicit_param_p = true;
 149               break;
 150
 151             case 'C':
 152               /* For c-100: print quotient of value by 96, if nonzero,
 153                  then do like %+.  */
 154               if (tem >= 96)
 155                 {
 156                   *op++ = tem / 96;
 157                   tem %= 96;
 158                 }
 159               FALLTHROUGH;
 160             case '+':           /* %+x means add character code of char x.  */
 161               tem += *p++;
 162               FALLTHROUGH;
 163             case '.':           /* %. means output as character.  */
 164               if (left)
 165                 {
 166                   /* If want to forbid output of 0 and \n and \t,
 167                      and this is one of them, increment it.  */
 168                   while (tem == 0 || tem == '\n' || tem == '\t')
 169                     {
 170                       ptrdiff_t append_len_incr;
 171                       tem++;
 172                       if (argp == old_argp)
 173                         doup++, append_len_incr = strlen (up);
 174                       else
 175                         doleft++, append_len_incr = strlen (left);
 176                       if (INT_ADD_WRAPV (append_len_incr,
 177                                          append_len, &append_len))
 178                         memory_full (SIZE_MAX);
 179                     }
 180                 }
 181               *op++ = tem ? tem : 0200;
 182               FALLTHROUGH;
 183             case 'f':           /* %f means discard next arg.  */
 184               argp++;
 185               break;
 186
 187             case 'b':           /* %b means back up one arg (and re-use it).  */
 188               argp--;
 189               break;
 190
 191             case 'r':           /* %r means interchange following two args.  */
 192               argp[0] = argp[1];
 193               argp[1] = tem;
 194               old_argp++;
 195               break;
 196
 197             case '>':           /* %>xy means if arg is > char code of x, */
 198               if (argp[0] > *p++) /* then add char code of y to the arg, */
 199                 argp[0] += *p;  /* and in any case don't output.  */
 200               p++;              /* Leave the arg to be output later.  */
 201               break;
 202
 203             case 'a':           /* %a means arithmetic.  */
 204               /* Next character says what operation.
 205                  Add or subtract either a constant or some other arg.  */
 206               /* First following character is + to add or - to subtract
 207                  or = to assign.  */
 208               /* Next following char is 'p' and an arg spec
 209                  (0100 plus position of that arg relative to this one)
 210                  or 'c' and a constant stored in a character.  */
 211               tem = p[2] & 0177;
 212               if (p[1] == 'p')
 213                 tem = argp[tem - 0100];
 214               if (p[0] == '-')
 215                 argp[0] -= tem;
 216               else if (p[0] == '+')
 217                 argp[0] += tem;
 218               else if (p[0] == '*')
 219                 argp[0] *= tem;
 220               else if (p[0] == '/')
 221                 argp[0] /= tem;
 222               else
 223                 argp[0] = tem;
 224
 225               p += 3;
 226               break;
 227
 228             case 'i':           /* %i means add one to arg, */
 229               argp[0] ++;       /* and leave it to be output later.  */
 230               argp[1] ++;       /* Increment the following arg, too!  */
 231               break;
 232
 233             case '%':           /* %% means output %; no arg.  */
 234               goto ordinary;
 235
 236             case 'n':           /* %n means xor each of next two args with 140.  */
 237               argp[0] ^= 0140;
 238               argp[1] ^= 0140;
 239               break;
 240
 241             case 'm':           /* %m means xor each of next two args with 177.  */
 242               argp[0] ^= 0177;
 243               argp[1] ^= 0177;
 244               break;
 245
 246             case 'B':           /* %B means express arg as BCD char code.  */
 247               argp[0] += 6 * (tem / 10);
 248               break;
 249
 250             case 'D':           /* %D means weird Delta Data transformation.  */
 251               argp[0] -= 2 * (tem % 16);
 252               break;
 253
 254             default:
 255               emacs_abort ();
 256             }
 257         }
 258       else
 259         /* Ordinary character in the argument string.  */
 260       ordinary:
 261         *op++ = c;
 262     }
 263   *op = 0;
 264   while (doup-- > 0)
 265     op = stpcpy (op, up);
 266   while (doleft-- > 0)
 267     op = stpcpy (op, left);
 268   return outstring;
 269 }
 270 \f
 271 #ifdef DEBUG
 272
 273 int
 274 main (int argc, char **argv)
 275 {
 276   char buf[50];
 277   int args[3];
 278   args[0] = atoi (argv[2]);
 279   args[1] = atoi (argv[3]);
 280   args[2] = atoi (argv[4]);
 281   tparam1 (argv[1], buf, 50, "LEFT", "UP", args);
 282   printf ("%s\n", buf);
 283   return 0;
 284 }
 285
 286 #endif /* DEBUG */