1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
|
/*
** PushDir() and PopDir()
**
** Original Copyright 1988-1991 by Bob Stout as part of
** the MicroFirm Function Library (MFL)
**
** This subset version is an expanded version of the one
** originally published by the author in Tech Specialist
** magazine and is hereby donated to the public domain.
*/
#include <dos.h>
#include <stdlib.h>
#include <string.h>
#include <ctype.h>
#ifdef __TURBOC__
#include <dir.h>
#else
#include <direct.h>
#endif
#define DIR_STACK_SIZE 8
#define MAX_FLEN 67
typedef enum {ERROR = -1, FALSE, TRUE} LOGICAL;
#define BOOL(x) (!(!(x)))
/*
** NOTE: Uses the author's chdrv(), also in SNIPPETS!
*/
int chdrv(int);
static int PushDir_stack_ptr;
static char PushDir_stack[DIR_STACK_SIZE][MAX_FLEN];
/*
** PushDir()
**
** Like chdir(), except a drive may be specified and the old directory
** is saved.
**
** Arguments: 1 - newdir, the buffer containing the new directory name
**
** Returns: -1 - stack overflow
** 0 - error
** 1 - success, still on same drive
** 2 - success, changed drive
**
** Side effects: Converts name in newdir to upper case and prepends
** a drive letter.
**
** CAUTION: Since a drive will be prepended to newdir, it's buffer
** should be at at least MAX_FLEN long.
*/
int PushDir(char *newdir)
{
char pname[MAX_FLEN];
char drive[3];
char *target = &pname[2];
int new_drv = 0, ercode = 0;
static int init = 0;
if (!init)
PushDir_stack_ptr = init = -1;
if (DIR_STACK_SIZE <= ++PushDir_stack_ptr)
{
ercode = -1;
goto ErrEx;
}
getcwd(PushDir_stack[PushDir_stack_ptr], MAX_FLEN);
strupr(PushDir_stack[PushDir_stack_ptr]);
strncpy(drive, PushDir_stack[PushDir_stack_ptr], 2);
drive[2] = '\0';
if (':' == newdir[1])
{ /* If a drive is specified */
strupr(newdir);
strcpy(pname, newdir);
if (strchr(target, ':')) /* if filename is illegal */
goto ErrEx;
if (*drive != *newdir)
{
if (ERROR == chdrv(newdir[0] - 'A'))
{ /* If the drive is invalid */
goto ErrEx;
}
else new_drv = 1;
}
}
else
{ /* If a drive isn't specified */
if (!strchr(strupr(newdir), ':'))
{ /* If legal filename */
strcpy(pname, drive);
strcat(pname, newdir);
strcpy(newdir, pname);
}
else
{ /* If filename is illegal */
goto ErrEx;
}
}
if (*target)
{
if (chdir(target))
{
if (1 == new_drv) /* We already changed drives */
chdrv(*drive - 'A'); /* Go home before exit */
goto ErrEx;
}
}
return (new_drv + 1);
ErrEx:
--PushDir_stack_ptr;
return (ercode);
}
/*
** PopDir()
**
** Like chdir(), except goes to the drive/directory specified on the
** top of the PushDir stack.
**
** Arguments: none
**
** Returns: -1 - stack empty
** 0 - error - stack pointer unchanged
** 1 - success, still on same drive
** 2 - success, changed drive
**
** Side effects: none
**
** CAUTION: chdir() or chdrv() should not be called between PushDir-
** PopDir calls.
*/
int PopDir(void)
{
char I_am_here[MAX_FLEN], target_drv, *target;
int new_drv = 0;
if (0 > PushDir_stack_ptr)
return -1;
getcwd(I_am_here, MAX_FLEN);
target = &PushDir_stack[PushDir_stack_ptr][2];
target_drv = PushDir_stack[PushDir_stack_ptr][0];
if (I_am_here[0] != target_drv)
{
if (ERROR == chdrv(target_drv - 'A'))
return 0;
new_drv = 1;
}
if (!chdir(target))
{
--PushDir_stack_ptr;
return (1 + new_drv);
}
else return 0;
}
/*
** isdir()
**
** Checks to see if a drive and/or path are a valid directory.
**
** Arguments: 1 - dir, the buffer containing the new directory name
**
** Returns: ERROR - push/popdir stack overflow
** FALSE - not a valid directory
** TRUE - valid directory
**
** Side effects: Converts name in dir to upper case and prepends a
** drive letter.
**
** CAUTION: Since a drive will be prepended to newdir, it's buffer
** should be at at least MAX_FLEN long.
*/
int isdir(char *dir)
{
int ercode;
if (-1 == (ercode = PushDir(dir)))
return ercode;
if (ercode)
PopDir();
return BOOL(ercode);
}
|
