Subversion Repositories SvarDOS

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

 * of the MIT license.

 *

 * Copyright (C) 2021-2023 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 WITHSTDIO is enabled, then remap file operations to use the standard

 * stdio amenities */

#ifdef WITHSTDIO

#include <stdio.h>   /* FILE, fopen(), fseek(), etc */

typedef FILE* FHANDLE;

#define FOPEN(x) fopen(x, "rb")

#define FCLOSE(x) fclose(x)

#define FSEEK(f,b) fseek(f,b,SEEK_CUR)

#define FREAD(f,t,b) fread(t, 1, b, f)

#else

#include <i86.h>

typedef unsigned short FHANDLE;

#endif

#include <stdlib.h>  /* NULL */

#include <string.h>  /* memcmp(), strcpy() */

#include "svarlang.h"

/* supplied through DEFLANG.C */

extern char svarlang_mem[];

extern const unsigned short svarlang_memsz;

const char *svarlang_strid(unsigned short id) {

  const char *ptr = svarlang_mem;

  /* find the string id in langblock memory */

  for (;;) {

    if (((unsigned short *)ptr)[0] == id) return(ptr + 4);

    if (((unsigned short *)ptr)[1] == 0) return(ptr + 2); /* end of strings - return an empty string */

    ptr += ((unsigned short *)ptr)[1] + 4;

  }

}

/* routines below are simplified (dos-based) versions of the libc FILE-related

 * functions. Using them avoids a dependency on FILE, hence makes the binary

 * smaller if the application does not need to pull fopen() and friends */

#ifndef WITHSTDIO

static unsigned short FOPEN(const char *s) {

  unsigned short fname_seg = FP_SEG(s);

  unsigned short fname_off = FP_OFF(s);

  unsigned short res = 0; /* fd 0 is already used by stdout so it's a good error value */

  _asm {

    push dx

    push ds

    mov ax, fname_seg

    mov dx, fname_off

    mov ds, ax

    mov ax, 0x3d00  /* open file, read-only (fname at DS:DX) */

    int 0x21

    pop ds

    jc ERR

    mov res, ax

    ERR:

    pop dx

  }

  return(res);

}

static void FCLOSE(unsigned short handle) {

  _asm {

    push bx

    mov ah, 0x3e

    mov bx, handle

    int 0x21

    pop bx

  }

}

static unsigned short FREAD(unsigned short handle, void *buff, unsigned short bytes) {

  unsigned short buff_seg = FP_SEG(buff);

  unsigned short buff_off = FP_OFF(buff);

  unsigned short res = 0;

  _asm {

    push bx

    push cx

    push dx

    mov bx, handle

    mov cx, bytes

    mov dx, buff_off

    mov ax, buff_seg

    push ds

    mov ds, ax

    mov ah, 0x3f    /* read cx bytes from file handle bx to DS:DX */

    int 0x21

    pop ds

    jc ERR

    mov res, ax

    ERR:

    pop dx

    pop cx

    pop bx

  }

  return(res);

}

static void FSEEK(unsigned short handle, unsigned short bytes) {

  _asm {

    push bx

    push cx

    push dx

    mov ax, 0x4201  /* move file pointer from cur pos + CX:DX */

    mov bx, handle

    xor cx, cx

    mov dx, bytes

    int 0x21

    pop dx

    pop cx

    pop bx

  }

}

#endif

int svarlang_load(const char *fname, const char *lang) {

  unsigned short langid;

  char hdr[4];

  unsigned short buff16[2];

  FHANDLE fd;

  langid = *((unsigned short *)lang);

  langid &= 0xDFDF; /* make sure lang is upcase */

  fd = FOPEN(fname);

  if (!fd) return(-1);

  /* read hdr, should be "SvL\33" */

  if ((FREAD(fd, hdr, 4) != 4) || (memcmp(hdr, "SvL\33", 4) != 0)) {

    FCLOSE(fd);

    return(-3);

  }

  /* read next lang id in file */

  while (FREAD(fd, buff16, 4) == 4) {

    /* is it the lang I am looking for? */

    if (buff16[0] != langid) { /* skip to next lang */

      FSEEK(fd, buff16[1]);

      continue;

    }

    /* found - but do I have enough memory space? */

    if (buff16[1] >= svarlang_memsz) {

      FCLOSE(fd);

      return(-4);

    }

    /* load strings */

    if (FREAD(fd, svarlang_mem, buff16[1]) != buff16[1]) break;

    FCLOSE(fd);

    return(0);

  }

  FCLOSE(fd);

  return(-5);

}