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/* 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> /* FP_SEG, FP_OFF */
typedef unsigned short FHANDLE;
#endif
#include "svarlang.h"
/* supplied through DEFLANG.C */
extern char svarlang_mem[];
extern unsigned short svarlang_dict[];
extern const unsigned short svarlang_memsz;
extern const unsigned short svarlang_string_count;
const char *svarlang_strid(unsigned short id) {
unsigned short left = 0, right = svarlang_string_count - 1, x;
unsigned short v;
if (svarlang_string_count == 0) return("");
while (left <= right) {
x = left + ((right - left ) >> 2);
v = svarlang_dict[x * 2];
if (id == v) return(svarlang_mem + svarlang_dict[x * 2 + 1]);
if (id > v) {
left = x + 1;
} else {
right = x - 1;
}
}
return("");
}
/* 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;
unsigned short buff16[2];
FHANDLE fd;
struct {
unsigned long sig;
unsigned short string_count;
} hdr;
langid = *((unsigned short *)lang);
langid &= 0xDFDF; /* make sure lang is upcase */
fd = FOPEN(fname);
if (!fd) return(-1);
/* read hdr, sig should be "SvL\x1a" (0x1a4c7653) */
if ((FREAD(fd, &hdr, 6) != 6) || (hdr.sig != 0x1a4c7653L) || (hdr.string_count != svarlang_string_count)) {
FCLOSE(fd);
return(-2);
}
for (;;) {
/* read next lang id and string table size in file */
if (FREAD(fd, buff16, 4) != 4) {
FCLOSE(fd);
return(-3);
}
/* is it the lang I am looking for? */
if (buff16[0] == langid) break;
/* skip to next lang */
FSEEK(fd, svarlang_string_count * 4);
FSEEK(fd, buff16[1]);
}
/* found - but do I have enough memory space? */
if (buff16[1] >= svarlang_memsz) {
FCLOSE(fd);
return(-4);
}
/* load dictionary & strings */
if ((FREAD(fd, svarlang_dict, svarlang_string_count * 4) != svarlang_string_count * 4) ||
(FREAD(fd, svarlang_mem, buff16[1]) != buff16[1])) {
FCLOSE(fd);
return(-5);
}
FCLOSE(fd);
return(0);
}