Subversion Repositories SvarDOS

/* entry point for internal commands

 * matches internal commands and executes them

 * returns -1 or exit code if processed

 * returns -2 if command unrecognized */

#include <i86.h>

#include <stdio.h>

#include <stdlib.h>

#include "doserr.h"

#include "helpers.h"

struct cmd_funcparam {

  int argc;

  const char *argv[256];

  unsigned short env_seg;

  const char far *cmdline;

};

#include "cmd/cd.c"

#include "cmd/exit.c"

#include "cmd/set.c"

#include "cmd.h"

struct CMD_ID {

  const char *cmd;

  int (*func_ptr)(const struct cmd_funcparam *); /* pointer to handling function */

};

const struct CMD_ID INTERNAL_CMDS[] = {

  {"CD",      cmd_cd},

  {"CHDIR",   cmd_cd},

  {"EXIT",    cmd_exit},

  {"SET",     cmd_set},

  {NULL,      NULL}

};

/* NULL if cmdline is not matching an internal command, otherwise returns a

 * pointer to a CMD_ID struct */

static const struct CMD_ID *cmd_match(const char far *cmdline, unsigned short *argoffset) {

  unsigned short i;

  char buff[10];

  /* copy command to buffer, until space, NULL, tab, return, dot, slash or backslash */

  for (i = 0; i < 9; i++) {

    if (cmdline[i] == ' ') break;

    if (cmdline[i] == 0) break;

    if (cmdline[i] == '\t') break;

    if (cmdline[i] == '\r') break;

    if (cmdline[i] == '.') break;

    if (cmdline[i] == '/') break;

    if (cmdline[i] == '\\') break;

    buff[i] = cmdline[i];

  }

  buff[i] = 0;

  /* advance to nearest non-space to find where arguments start */

  while (cmdline[i] == ' ') i++;

  *argoffset = i;

  /* try matching an internal command */

  for (i = 0; INTERNAL_CMDS[i].cmd != NULL; i++) {

    /*printf("imatch(%s,%s)\r\n", buff, INTERNAL_CMDS[i].cmd); */

    if (imatch(buff, INTERNAL_CMDS[i].cmd)) {

      /*printf("match cmd i=%u (buff=%s)\r\n", i, buff);*/

      return(&(INTERNAL_CMDS[i]));

    }

  }

  return(NULL); /* command is not recognized as internal */

}

/* explodes a command into an array of arguments where last arg is NULL

 * returns number of args */

unsigned short cmd_explode(char *buff, const char far *s, char const **argvlist) {

  int si = 0, argc = 0, i = 0;

  for (;;) {

    /* skip to next non-space character */

    while (s[si] == ' ') si++;

    /* end of string? */

    if (s[si] == 0) break;

    /* set argv ptr */

    argvlist[argc++] = buff + i;

    /* find next space while copying arg to local buffer */

    do {

      buff[i++] = s[si++];

    } while (s[si] != ' ' && s[si] != 0 && s[si] != '/');

    buff[i++] = 0;

    /* is this end of string? */

    if (s[si] == 0) break;

  }

  argvlist[argc] = NULL;

  return(argc);

}

int cmd_process(unsigned short env_seg, const char far *cmdline) {

  const struct CMD_ID *cmdptr;

  struct cmd_funcparam p;

  unsigned short argoffset;

  char cmdbuff[256];

  /* special case: is this a drive change? (like "E:") */

  if ((cmdline[0] != 0) && (cmdline[1] == ':') && ((cmdline[2] == ' ') || (cmdline[2] == 0))) {

    if (((cmdline[0] >= 'a') && (cmdline[0] <= 'z')) || ((cmdline[0] >= 'A') && (cmdline[0] <= 'Z'))) {

      unsigned char drive = cmdline[0];

      unsigned char curdrive = 0;

      if (drive >= 'a') {

        drive -= 'a';

      } else {

        drive -= 'A';

      }

      _asm {

        push ax

        push dx

        mov ah, 0x0e     /* DOS 1+ - SELECT DEFAULT DRIVE */

        mov dl, drive    /* DL = new default drive (00h = A:, 01h = B:, etc) */

        int 0x21

        mov ah, 0x19     /* DOS 1+ - GET CURRENT DRIVE */

        int 0x21

        mov curdrive, al /* cur drive (0=A, 1=B, etc) */

        pop dx

        pop ax

      }

      if (curdrive != drive) puts(doserr(0x0f));

      return(-1);

    }

  }

  /* try matching an internal command */

  cmdptr = cmd_match(cmdline, &argoffset);

  if (cmdptr == NULL) return(-2); /* command is not recognized as internal */

  /* printf("recognized internal command: '%s', tail of command at offset %u\r\n", cmdptr->cmd, argoffset); */

  /* prepare function parameters and feed it to the cmd handling function */

  p.argc = cmd_explode(cmdbuff, cmdline + argoffset, p.argv);

  p.env_seg = env_seg;

  p.cmdline = cmdline;

  return((cmdptr->func_ptr)(&p));

}