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Cream of the Crop 1
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SNIP1292.ARJ
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SETENVAR.C
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C/C++ Source or Header
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1992-12-26
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156 lines
/*
** SETENVAR.C - Program which sets the DOS master environment upon exit
**
** Original Copyright 1988-1991 by Bob Stout as part of
** the MicroFirm Function Library (MFL)
**
** This subset version is functionally identical to the
** version originally published by the author in Tech Specialist
** magazine and is hereby donated to the public domain.
*/
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <conio.h>
#include <dos.h>
#if !defined(__ZTC__) && !defined(__TURBOC__)
#define MK_FP(seg,offset) \
((void far *)(((unsigned long)(seg)<<16) | (unsigned)(offset)))
#define peek(s,o) (*((unsigned far *)(MK_FP(s,o))))
#define poke(s,o,w) (*((unsigned far *)(MK_FP(s,o)))=(w))
#endif
#define SUCCESS 0
#define ERROR -1
static unsigned head, tail, start, end;
static int idx = 0;
static unsigned keystack[16][2];
/*
** ungetkey()
**
** Stuffs characters into the keyboard buffer.
**
** Parameters: 1 - Extended character to stuff
**
** Returns: SUCCESS or EOF
**
** Note: This function assumes that the keyboard buffer is in
** the normal (for IBM) location of 40:1E.
**
*/
int ungetkey(unsigned key)
{
int count;
#ifdef __ZTC__
peek(0x40, 0x1a, &head, sizeof(unsigned));
peek(0x40, 0x1c, &tail, sizeof(unsigned));
peek(0x40, 0x80, &start, sizeof(unsigned));
peek(0x40, 0x82, &end, sizeof(unsigned));
#else
head = peek(0x40, 0x1a);
tail = peek(0x40, 0x1c);
start = peek(0x40, 0x80);
end = peek(0x40, 0x82);
#endif
count = tail - head;
if (0 > count)
count += (16 * sizeof(unsigned));
count >>= 1;
if (15 > count)
{
#ifdef __ZTC__
peek(0x40, tail, &keystack[idx][0], sizeof(unsigned));
#else
keystack[idx][0] = peek(0x40, tail);
#endif
keystack[idx][1] = tail;
#ifdef __ZTC__
poke(0x40, tail, &key, sizeof(unsigned));
#else
poke(0x40, tail, key);
#endif
tail += sizeof(unsigned);
if (end <= tail)
tail = start;
#ifdef __ZTC__
poke(0x40, 0x1c, &tail, sizeof(unsigned));
#else
poke(0x40, 0x1c, tail);
#endif
return key;
}
return EOF;
}
/*
** KB_stuff()
**
** Stuffs strings into the keyboard buffer.
**
** Parameters: 1 - String to stuff
**
** Returns: SUCCESS if successful
** ERROR in case of error, plus beyboard buffer is
** restored
**
** Note: This function assumes that the keyboard buffer is in
** the normal (for IBM) location of 40:1E.
*/
int KB_stuff(char *str)
{
int ercode = SUCCESS;
idx = 0;
while (*str)
{
if (EOF == ungetkey((unsigned)(*str++)))
{
while (0 <= --idx)
{
tail = keystack[idx][1];
#ifdef __ZTC__
poke(0x40, tail, &keystack[idx][0],
sizeof(unsigned));
#else
poke(0x40, tail, keystack[idx][0]);
#endif
}
#ifdef __ZTC__
poke(0x40, 0x1c, &tail, sizeof(unsigned));
#else
poke(0x40, 0x1c, tail);
#endif
ercode = ERROR;
break;
}
else ++idx;
}
idx = 0;
return ercode;
}
void main(int argc, char *argv[])
{
FILE *bfile;
if (3 > argc)
{
puts("\aUsage: SETENVAR envar datum");
abort();
}
bfile = fopen("$TMP$.BAT", "w");
fprintf(bfile, "SET %s=%s\ndel $tmp$.bat\x1a", argv[1], argv[2]);
fclose(bfile);
while (kbhit())
getch();
KB_stuff("$tmp$\r");
}