Subversion Repositories SvarDOS

/* This file is part of the SvarCOM project and is published under the terms

 * of the MIT license.

 *

 * Copyright (C) 2021-2022 Mateusz Viste

 *

 * Permission is hereby granted, free of charge, to any person obtaining a

 * copy of this software and associated documentation files (the "Software"),

 * to deal in the Software without restriction, including without limitation

 * the rights to use, copy, modify, merge, publish, distribute, sublicense,

 * and/or sell copies of the Software, and to permit persons to whom the

 * Software is furnished to do so, subject to the following conditions:

 *

 * The above copyright notice and this permission notice shall be included in

 * all copies or substantial portions of the Software.

 *

 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR

 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,

 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE

 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER

 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING

 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER

 * DEALINGS IN THE SOFTWARE.

 */

/*

 * if [not] exists

 * if [not] errorlevel 1

 * if [not] string ==string (string==string and string == string works, too)

 * if [not] errorlevel == 1   <-- I do NOT support this one, even though

 *                                MSDOS 5 and 6 considers it equivalent to

 *                                IF ERRORLEVEL 1. This is a misleading and

 *                                undocumented syntax (does not actually

 *                                check for equality).

 */

#define JMP_NEXT_ARG(s) while ((*s != ' ') && (*s != 0)) s++; while (*s == ' ') s++;

static enum cmd_result cmd_if(struct cmd_funcparam *p) {

  unsigned char negflag = 0;

  unsigned short i;

  const char *s = p->cmdline + p->argoffset;

  /* help screen ONLY if /? is the only argument - I do not want to output

   * help for ex. for "if %1 == /? echo ..." */

  if ((p->argc == 1) && (imatch(p->argv[0], "/?"))) {

    nls_outputnl(35,0); /* "Performs conditional processing in batch programs." */

    outputnl("");

    nls_outputnl(35,1); /* "IF [NOT] ERRORLEVEL num command" */

    nls_outputnl(35,2); /* "IF [NOT] string1==string2 command" */

    nls_outputnl(35,3); /* "IF [NOT] EXIST filename command" */

    outputnl("");

    nls_outputnl(35,4); /* "NOT               command is executed only if condition is NOT met" */

    nls_outputnl(35,5); /* "ERRORLEVEL num    condition: last program returned an exit code >= num" */

    nls_outputnl(35,6); /* "string1==string2  condition: both strings must be equal" */

    nls_outputnl(35,7); /* "EXIST filename    condition: filename exists (wildcards accepted)" */

    nls_outputnl(35,8); /* "command           command to carry out if condition is met" */

    return(CMD_OK);

  }

  /* negation? */

  if (imatchlim(s, "NOT ", 4)) {

    negflag = 1;

    JMP_NEXT_ARG(s);

  }

  /* IF ERRORLEVEL x cmd */

  if (imatchlim(s, "ERRORLEVEL ", 11)) {

    unsigned char far *rmod_exitcode = MK_FP(p->rmod->rmodseg, RMOD_OFFSET_LEXITCODE);

    JMP_NEXT_ARG(s);

    if (*s == 0) goto SYNTAX_ERR;

    /* convert errorlevel to an uint */

    if ((*s < '0') || (*s > '9')) {

      i = 0xffff;

    } else {

      atous(&i, s);

    }

    /* move s to command */

    JMP_NEXT_ARG(s);

    /* is errorlevel matching? */

    if (i <= *rmod_exitcode) negflag ^= 1;

    goto EXEC_S_CMD_IF_NEGFLAG_SET;

  }

  /* IF EXIST fname (or wildcard)

   * TODO: checking for a file on an empty diskette drive should NOT lead bother

   *       the user with the stupid 'retry, abort, fail' query! */

  if (imatchlim(s, "EXIST ", 6)) {

    struct DTA *dta = (void *)(0x80); /* default dta location */

    JMP_NEXT_ARG(s);

    /* copy filename to buffer */

    for (i = 0; (s[i] != ' ') && (s[i] != 0); i++) p->BUFFER[i] = s[i];

    p->BUFFER[i] = 0;

    /* move s to command */

    JMP_NEXT_ARG(s);

    if (*s == 0) goto SYNTAX_ERR; /* check now to avoid moving the diskette drive if syntax bad anyway */

    /* does file exist? */

    if (findfirst(dta, p->BUFFER, 0) == 0) negflag ^= 1;

    goto EXEC_S_CMD_IF_NEGFLAG_SET;

  }

  /* IF str1==str2 ? (and if that's not it, then it's a syntax error) */

  if (strstr(s, "==") != NULL) {

    /* copy first argument to BUFF, until first '=' or space */

    for (i = 0; (s[i] != '=') && (s[i] != ' '); i++) p->BUFFER[i] = s[i];

    /* 1st arg cannot be empty */

    if (i == 0) goto SYNTAX_ERR;

    /* terminate buff string and move s forward to the equality char (or space) */

    p->BUFFER[i++] = 0;

    s += i;

    while (*s == ' ') s++;

    /* if second char is not a '=' then syntax error (equality sign is not

     * allowed in first string) */

    if (*s != '=') goto SYNTAX_ERR;

    /* skip all trailing equality chars (MSDOS accepts many of them, ie all

     * these are fine: "dupa==dupa", "dupa===dupa", "dupa====dupa", etc) */

    while (*s == '=') s++;

    while (*s == ' ') s++; /* skip any leading spaces */

    /* move along until space or NULL terminator, checking equality */

    for (i = 0; (p->BUFFER[i] != 0) && (p->BUFFER[i] == s[i]); i++);

    if ((p->BUFFER[i] == 0) && (s[i] == ' ')) negflag ^= 1;

    JMP_NEXT_ARG(s);

    goto EXEC_S_CMD_IF_NEGFLAG_SET;

  }

  /* invalid syntax */

  SYNTAX_ERR:

  nls_outputnl(0,1); /* "Invalid syntax" */

  return(CMD_FAIL);

  /* let's exec command (write it to start of cmdline and parse again) */

  EXEC_S_CMD_IF_NEGFLAG_SET:

  if (*s == 0) goto SYNTAX_ERR;

  if (negflag == 0) return(CMD_OK);

  memmove((void *)(p->cmdline), s, strlen(s) + 1);  /* cmdline and s share the same memory! */

  return(CMD_CHANGED);

}