/* Substitution of parameters in strings from terminal descriptions.
   Copyright (C) 2006-2023 Free Software Foundation, Inc.

   This file is free software: you can redistribute it and/or modify
   it under the terms of the GNU Lesser General Public License as
   published by the Free Software Foundation, either version 3 of the
   License, or (at your option) any later version.

   This file 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 Lesser General Public License for more details.

   You should have received a copy of the GNU Lesser General Public License
   along with this program.  If not, see <https://www.gnu.org/licenses/>.  */

/* Originally by Ross Ridge, Public Domain, 92/02/01 07:30:36 */

#include <config.h>

#include <stdarg.h>
#include <stdio.h>
#include <string.h>

#include "attribute.h"
#include "c-ctype.h"

#ifdef USE_SCCS_IDS
static const char SCCSid[] = "@(#) mytinfo tparm.c 3.2 92/02/01 public domain, By Ross Ridge";
#endif

#ifndef MAX_PUSHED
#define MAX_PUSHED      32
#endif

#define ARG     1
#define NUM     2

#define INTEGER 1
#define STRING  2

#define MAX_LINE 640

typedef struct stack_str
{
  int type;
  int argnum;
  int value;
} stack;

static stack S[MAX_PUSHED];
static stack vars['z'-'a'+1];
static int pos = 0;

static
struct arg_str
{
  int type;
  int integer;
  char *string;
} arg_list[10];

static int argcnt;

static va_list tparm_args;

static int
pusharg (int arg)
{
  if (pos == MAX_PUSHED)
    return 1;
  S[pos].type = ARG;
  S[pos++].argnum = arg;
  return 0;
}

static int
pushnum (int num)
{
  if (pos == MAX_PUSHED)
    return 1;
  S[pos].type = NUM;
  S[pos++].value = num;
  return 0;
}

static int
getarg (int argnum, int type, void *p)
{
  while (argcnt < argnum)
    {
      arg_list[argcnt].type = INTEGER;
      arg_list[argcnt++].integer = (int) va_arg (tparm_args, int);
    }
  if (argcnt > argnum)
    {
      if (arg_list[argnum].type != type)
        return 1;
      else if (type == STRING)
        *(char **)p = arg_list[argnum].string;
      else
        *(int *)p = arg_list[argnum].integer;
    }
  else
    {
      arg_list[argcnt].type = type;
      if (type == STRING)
        *(char **)p = arg_list[argcnt++].string = (char *) va_arg (tparm_args, char *);
      else
        *(int *)p = arg_list[argcnt++].integer = (int) va_arg (tparm_args, int);
    }
  return 0;
}

static int
popstring (char **str)
{
  if (pos-- == 0)
    return 1;
  if (S[pos].type != ARG)
    return 1;
  return getarg (S[pos].argnum, STRING, str);
}

static int
popnum (int *num)
{
  if (pos-- == 0)
    return 1;
  switch (S[pos].type)
    {
    case ARG:
      return  getarg (S[pos].argnum, INTEGER, num);
    case NUM:
      *num = S[pos].value;
      return 0;
    }
  return 1;
}

static int
cvtchar (const char *sp, char *c)
{
  switch (*sp)
    {
    case '\\':
      switch (*++sp)
        {
        case '\'':
        case '$':
        case '\\':
        case '%':
          *c = *sp;
          return 2;
        case '\0':
          *c = '\\';
          return 1;
        case '0':
          if (sp[1] == '0' && sp[2] == '0')
            {
              *c = '\0';
              return 4;
            }
          *c = '\200'; /* '\0' ???? */
          return 2;
        default:
          *c = *sp;
          return 2;
        }
    default:
      *c = *sp;
      return 1;
    }
}

/* sigh... this has got to be the ugliest code I've ever written.
   Trying to handle everything has its cost, I guess.

   It actually isn't too hard to figure out if a given % code is supposed
   to be interpreted with its termcap or terminfo meaning since almost
   all terminfo codes are invalid unless something has been pushed on
   the stack and termcap strings will never push things on the stack
   (%p isn't used by termcap). So where we have a choice we make the
   decision by whether or not something has been pushed on the stack.
   The static variable termcap keeps track of this; it starts out set
   to 1 and is incremented for each argument processed for a termcap % code,
   however if something is pushed on the stack it's set to 0 and the
   rest of the % codes are interpreted as terminfo % codes. Another way
   of putting it is that if termcap equals one we haven't decided either
   way yet, if it equals zero we're looking for terminfo codes, and if
   its greater than 1 we're looking for termcap codes.

   Terminfo % codes:

        %%      output a '%'
        %[[:][-+# ][width][.precision]][doxXs]
                output pop according to the printf format
        %c      output pop as a char
        %'c'    push character constant c.
        %{n}    push decimal constant n.
        %p[1-9] push parameter [1-9]
        %g[a-z] push variable [a-z]
        %P[a-z] put pop in variable [a-z]
        %l      push the length of pop (a string)
        %+      add pop to pop and push the result
        %-      subtract pop from pop and push the result
        %*      multiply pop and pop and push the result
        %&      bitwise and pop and pop and push the result
        %|      bitwise or pop and pop and push the result
        %^      bitwise xor pop and pop and push the result
        %~      push the bitwise not of pop
        %=      compare if pop and pop are equal and push the result
        %>      compare if pop is less than pop and push the result
        %<      compare if pop is greater than pop and push the result
        %A      logical and pop and pop and push the result
        %O      logical or pop and pop and push the result
        %!      push the logical not of pop
        %? condition %t if_true [%e if_false] %;
                if condition evaluates as true then evaluate if_true,
                else evaluate if_false. elseif's can be done:
        %? cond %t true [%e cond2 %t true2] ... [%e condN %t trueN] [%e false] %;
        %i      add one to parameters 1 and 2. (ANSI)

  Termcap Codes:

        %%      output a %
        %.      output parameter as a character
        %d      output parameter as a decimal number
        %2      output parameter in printf format %02d
        %3      output parameter in printf format %03d
        %+x     add the character x to parameter and output it as a character
(UW)    %-x     subtract parameter FROM the character x and output it as a char
(UW)    %ax     add the character x to parameter
(GNU)   %a[+*-/=][cp]x
                GNU arithmetic.
(UW)    %sx     subtract parameter FROM the character x
        %>xy    if parameter > character x then add character y to parameter
        %B      convert to BCD (parameter = (parameter/10)*16 + parameter%16)
        %D      Delta Data encode (parameter = parameter - 2*(parameter%16))
        %i      increment the first two parameters by one
        %n      xor the first two parameters by 0140
(GNU)   %m      xor the first two parameters by 0177
        %r      swap the first two parameters
(GNU)   %b      backup to previous parameter
(GNU)   %f      skip this parameter

  Note the two definitions of %a, the GNU definition is used if the characters
  after the 'a' are valid, otherwise the UW definition is used.

  (GNU) used by GNU Emacs termcap libraries
  (UW) used by the University of Waterloo (MFCF) termcap libraries

*/

char *
tparm (const char *str, ...)
{
  static int termcap;
  static char OOPS[] = "OOPS";
  static char buf[MAX_LINE];
  const char *sp;
  char *dp;
  char *fmt;
  char scan_for;
  int scan_depth;
  int if_depth;
  char fmt_buf[MAX_LINE];
  char sbuf[MAX_LINE];

  va_start (tparm_args, str);

  sp = str;
  dp = buf;
  scan_for = 0;
  scan_depth = 0;
  if_depth = 0;
  argcnt = 0;
  pos = 0;
  termcap = 1;
  while (*sp != '\0')
    {
      switch (*sp)
        {
        case '\\':
          if (scan_for)
            {
              if (*++sp != '\0')
                sp++;
              break;
            }
          *dp++ = *sp++;
          if (*sp != '\0')
            *dp++ = *sp++;
          break;
        case '%':
          sp++;
          if (scan_for)
            {
              if (*sp == scan_for && if_depth == scan_depth)
                {
                  if (scan_for == ';')
                    if_depth--;
                  scan_for = 0;
                }
              else if (*sp == '?')
                if_depth++;
              else if (*sp == ';')
                {
                  if (if_depth == 0)
                    return OOPS;
                  else
                    if_depth--;
                }
              sp++;
              break;
            }
          fmt = NULL;
          switch (*sp)
            {
            case '%':
              *dp++ = *sp++;
              break;
            case '+':
              if (!termcap)
                {
                  int i, j;
                  if (popnum (&j) || popnum (&i))
                    return OOPS;
                  i += j;
                  if (pushnum (i))
                    return OOPS;
                  sp++;
                  break;
                }
              FALLTHROUGH;
            case 'C':
              if (*sp == 'C')
                {
                  int i;
                  if (getarg (termcap - 1, INTEGER, &i))
                    return OOPS;
                  if (i >= 96)
                    {
                      i /= 96;
                      if (i == '$')
                        *dp++ = '\\';
                      *dp++ = i;
                    }
                }
              fmt = "%c";
              FALLTHROUGH;
            case 'a':
              if (!termcap)
                return OOPS;
              {
                int i;
                if (getarg (termcap - 1, INTEGER, &i))
                  return OOPS;
                if (*++sp == '\0')
                  return OOPS;
                if ((sp[1] == 'p' || sp[1] == 'c')
                    && sp[2] != '\0' && fmt == NULL)
                  {
                    /* GNU arithmetic parameter, what they really need is
                       terminfo.  */
                    int val;
                    int lc;
                    if (sp[1] == 'p'
                        && getarg (termcap - 1 + sp[2] - '@', INTEGER, &val))
                      return OOPS;
                    if (sp[1] == 'c')
                      {
                        char c;
                        lc = cvtchar (sp + 2, &c) + 2;
                        /* Mask out 8th bit so \200 can be used for \0 as per
                           GNU docs.  */
                        val = c & 0177;
                      }
                    else
                      lc = 2;
                    switch (sp[0])
                      {
                      case '=':
                        break;
                      case '+':
                        val = i + val;
                        break;
                      case '-':
                        val = i - val;
                        break;
                      case '*':
                        val = i * val;
                        break;
                      case '/':
                        val = i / val;
                        break;
                      default:
                        /* Not really GNU's %a after all... */
                        {
                          char c;
                          lc = cvtchar (sp, &c);
                          val = c + i;
                        }
                        break;
                      }
                    arg_list[termcap - 1].integer = val;
                    sp += lc;
                    break;
                  }
                {
                  char c;
                  sp += cvtchar (sp, &c);
                  arg_list[termcap - 1].integer = c + i;
                }
              }
              if (fmt == NULL)
                break;
              sp--;
              FALLTHROUGH;
            case '-':
              if (!termcap)
                {
                  int i, j;
                  if (popnum (&j) || popnum (&i))
                    return OOPS;
                  i -= j;
                  if (pushnum (i))
                    return OOPS;
                  sp++;
                  break;
                }
              fmt = "%c";
              FALLTHROUGH;
            case 's':
              if (termcap && (fmt == NULL || *sp == '-'))
                {
                  int i;
                  if (getarg (termcap - 1, INTEGER, &i))
                    return OOPS;
                  if (*++sp == '\0')
                    return OOPS;
                  {
                    char c;
                    sp += cvtchar (sp, &c);
                    arg_list[termcap - 1].integer = c - i;
                  }
                  if (fmt == NULL)
                    break;
                  sp--;
                }
              if (!termcap)
                return OOPS;
              FALLTHROUGH;
            case '.':
              if (termcap && fmt == NULL)
                fmt = "%c";
              FALLTHROUGH;
            case 'd':
              if (termcap && fmt == NULL)
                fmt = "%d";
              FALLTHROUGH;
            case '2':
              if (termcap && fmt == NULL)
                fmt = "%02d";
              FALLTHROUGH;
            case '3':
              if (termcap && fmt == NULL)
                fmt = "%03d";
              FALLTHROUGH;
            case ':': case ' ': case '#': case 'u':
            case 'x': case 'X': case 'o': case 'c':
            case '0': case '1': case '4': case '5':
            case '6': case '7': case '8': case '9':
              if (fmt == NULL)
                {
                  if (termcap)
                    return OOPS;
                  if (*sp == ':')
                    sp++;
                  fmt = fmt_buf;
                  *fmt++ = '%';
                  while (*sp != 's' && *sp != 'x' && *sp != 'X' && *sp != 'd'
                         && *sp != 'o' && *sp != 'c' && *sp != 'u')
                    {
                      if (*sp == '\0')
                        return OOPS;
                      *fmt++ = *sp++;
                    }
                  *fmt++ = *sp;
                  *fmt = '\0';
                  fmt = fmt_buf;
                }
              {
                char conv_char = fmt[strlen (fmt) - 1];
                if (conv_char == 's')
                  {
                    char *s;
                    if (popstring (&s))
                      return OOPS;
                    sprintf (sbuf, fmt, s);
                  }
                else
                  {
                    int i;
                    if (termcap)
                      {
                        if (getarg (termcap++ - 1, INTEGER, &i))
                          return OOPS;
                      }
                    else
                      if (popnum (&i))
                        return OOPS;
                    if (i == 0 && conv_char == 'c')
                      strcpy (sbuf, "\000");
                    else
                      sprintf (sbuf, fmt, i);
                  }
              }
              sp++;
              fmt = sbuf;
              while (*fmt != '\0')
                {
                  if (*fmt == '$')
                    *dp++ = '\\';
                  *dp++ = *fmt++;
                }
              break;
            case 'r':
              {
                int i;
                if (!termcap || getarg (1, INTEGER, &i))
                  return OOPS;
                arg_list[1].integer = arg_list[0].integer;
                arg_list[0].integer = i;
              }
              sp++;
              break;
            case 'i':
              {
                int i;
                if (getarg (1, INTEGER, &i) || arg_list[0].type != INTEGER)
                  return OOPS;
              }
              arg_list[1].integer++;
              arg_list[0].integer++;
              sp++;
              break;
            case 'n':
              {
                int i;
                if (!termcap || getarg (1, INTEGER, &i))
                  return OOPS;
              }
              arg_list[0].integer ^= 0140;
              arg_list[1].integer ^= 0140;
              sp++;
              break;
            case '>':
              if (!termcap)
                {
                  int i, j;
                  if (popnum (&j) || popnum (&i))
                    return OOPS;
                  i = (i > j);
                  if (pushnum (i))
                    return OOPS;
                  sp++;
                  break;
                }
              {
                int i;
                if (getarg (termcap-1, INTEGER, &i))
                  return OOPS;
                {
                  char c;
                  sp += cvtchar (sp, &c);
                  if (i > c)
                    {
                      sp += cvtchar (sp, &c);
                      arg_list[termcap-1].integer += c;
                    }
                  else
                    sp += cvtchar (sp, &c);
                }
              }
              sp++;
              break;
            case 'B':
              {
                int i;
                if (!termcap || getarg (termcap-1, INTEGER, &i))
                  return OOPS;
                arg_list[termcap-1].integer = 16 * (i / 10) + i % 10;
              }
              sp++;
              break;
            case 'D':
              {
                int i;
                if (!termcap || getarg (termcap-1, INTEGER, &i))
                  return OOPS;
                arg_list[termcap-1].integer = i - 2 * (i % 16);
              }
              sp++;
              break;
            case 'p':
              if (termcap > 1)
                return OOPS;
              if (*++sp == '\0')
                return OOPS;
              {
                int i = (*sp == '0' ? 9 : *sp - '1');
                if (i < 0 || i > 9)
                  return OOPS;
                if (pusharg (i))
                  return OOPS;
              }
              termcap = 0;
              sp++;
              break;
            case 'P':
              if (termcap || *++sp == '\0')
                return OOPS;
              {
                int i = *sp++ - 'a';
                if (i < 0 || i > 25)
                  return OOPS;
                if (pos-- == 0)
                  return OOPS;
                switch (vars[i].type = S[pos].type)
                  {
                  case ARG:
                    vars[i].argnum = S[pos].argnum;
                    break;
                  case NUM:
                    vars[i].value = S[pos].value;
                    break;
                  }
              }
              break;
            case 'g':
              if (termcap || *++sp == '\0')
                return OOPS;
              {
                int i = *sp++ - 'a';
                if (i < 0 || i > 25)
                  return OOPS;
                switch (vars[i].type)
                  {
                  case ARG:
                    if (pusharg (vars[i].argnum))
                      return OOPS;
                    break;
                  case NUM:
                    if (pushnum (vars[i].value))
                      return OOPS;
                    break;
                  }
              }
              break;
            case '\'':
              if (termcap > 1)
                return OOPS;
              if (*++sp == '\0')
                return OOPS;
              {
                char c;
                sp += cvtchar (sp, &c);
                if (pushnum (c) || *sp++ != '\'')
                  return OOPS;
              }
              termcap = 0;
              break;
            case '{':
              if (termcap > 1)
                return OOPS;
              {
                int i;
                i = 0;
                sp++;
                while (c_isdigit (*sp))
                  i = 10 * i + *sp++ - '0';
                if (*sp++ != '}' || pushnum (i))
                  return OOPS;
              }
              termcap = 0;
              break;
            case 'l':
              {
                int i;
                char *s;
                if (termcap || popstring (&s))
                  return OOPS;
                i = strlen (s);
                if (pushnum (i))
                  return OOPS;
              }
              sp++;
              break;
            case '*':
              {
                int i, j;
                if (termcap || popnum (&j) || popnum (&i))
                  return OOPS;
                i *= j;
                if (pushnum (i))
                  return OOPS;
              }
              sp++;
              break;
            case '/':
              {
                int i, j;
                if (termcap || popnum (&j) || popnum (&i))
                  return OOPS;
                i /= j;
                if (pushnum (i))
                  return OOPS;
              }
              sp++;
              break;
            case 'm':
              if (termcap)
                {
                  int i;
                  if (getarg (1, INTEGER, &i))
                    return OOPS;
                  arg_list[0].integer ^= 0177;
                  arg_list[1].integer ^= 0177;
                  sp++;
                  break;
                }
              {
                int i, j;
                if (popnum (&j) || popnum (&i))
                  return OOPS;
                i %= j;
                if (pushnum (i))
                  return OOPS;
              }
              sp++;
              break;
            case '&':
              {
                int i, j;
                if (popnum (&j) || popnum (&i))
                  return OOPS;
                i &= j;
                if (pushnum (i))
                  return OOPS;
              }
              sp++;
              break;
            case '|':
              {
                int i, j;
                if (popnum (&j) || popnum (&i))
                  return OOPS;
                i |= j;
                if (pushnum (i))
                  return OOPS;
              }
              sp++;
              break;
            case '^':
              {
                int i, j;
                if (popnum (&j) || popnum (&i))
                  return OOPS;
                i ^= j;
                if (pushnum (i))
                  return OOPS;
              }
              sp++;
              break;
            case '=':
              {
                int i, j;
                if (popnum (&j) || popnum (&i))
                  return OOPS;
                i = (i == j);
                if (pushnum (i))
                  return OOPS;
              }
              sp++;
              break;
            case '<':
              {
                int i, j;
                if (popnum (&j) || popnum (&i))
                  return OOPS;
                i = (i < j);
                if (pushnum (i))
                  return OOPS;
              }
              sp++;
              break;
            case 'A':
              {
                int i, j;
                if (popnum (&j) || popnum (&i))
                  return OOPS;
                i = (i && j);
                if (pushnum (i))
                  return OOPS;
              }
              sp++;
              break;
            case 'O':
              {
                int i, j;
                if (popnum (&j) || popnum (&i))
                  return OOPS;
                i = (i || j);
                if (pushnum (i))
                  return OOPS;
              }
              sp++;
              break;
            case '!':
              {
                int i;
                if (popnum (&i))
                  return OOPS;
                i = !i;
                if (pushnum (i))
                  return OOPS;
              }
              sp++;
              break;
            case '~':
              {
                int i;
                if (popnum (&i))
                  return OOPS;
                i = ~i;
                if (pushnum (i))
                  return OOPS;
              }
              sp++;
              break;
            case '?':
              if (termcap > 1)
                return OOPS;
              termcap = 0;
              if_depth++;
              sp++;
              break;
            case 't':
              {
                int i;
                if (popnum (&i) || if_depth == 0)
                  return OOPS;
                if (!i)
                  {
                    scan_for = 'e';
                    scan_depth = if_depth;
                  }
              }
              sp++;
              break;
            case 'e':
              if (if_depth == 0)
                return OOPS;
              scan_for = ';';
              scan_depth = if_depth;
              sp++;
              break;
            case ';':
              if (if_depth-- == 0)
                return OOPS;
              sp++;
              break;
            case 'b':
              if (--termcap < 1)
                return OOPS;
              sp++;
              break;
            case 'f':
              if (!termcap++)
                return OOPS;
              sp++;
              break;
            }
          break;
        default:
          if (scan_for)
            sp++;
          else
            *dp++ = *sp++;
          break;
        }
    }
  va_end (tparm_args);
  *dp = '\0';
  return buf;
}
