Subversion Repositories SvarDOS

Rev

Rev 388 | Rev 396 | Go to most recent revision | Details | Compare with Previous | Last modification | View Log | RSS feed

Rev Author Line No. Line
352 mateuszvis 1 
/*
2 
 * a variety of helper functions
3 
 * Copyright (C) 2021 Mateusz Viste
4 
 */
5 
 
6 
#include "helpers.h"
7 
 
8 
/* case-insensitive comparison of strings, returns non-zero on equality */
9 
int imatch(const char *s1, const char *s2) {
10 
  for (;;) {
11 
    char c1, c2;
12 
    c1 = *s1;
13 
    c2 = *s2;
14 
    if ((c1 >= 'a') && (c1 <= 'z')) c1 -= ('a' - 'A');
15 
    if ((c2 >= 'a') && (c2 <= 'z')) c2 -= ('a' - 'A');
16 
    /* */
17 
    if (c1 != c2) return(0);
18 
    if (c1 == 0) return(1);
19 
    s1++;
20 
    s2++;
21 
  }
22 
}
23 
 
24 
 
25 
/* returns zero if s1 starts with s2 */
26 
int strstartswith(const char *s1, const char *s2) {
27 
  while (*s2 != 0) {
28 
    if (*s1 != *s2) return(-1);
29 
    s1++;
30 
    s2++;
31 
  }
32 
  return(0);
33 
}
369 mateuszvis 34 
 
35 
 
36 
/* outputs a NULL-terminated string to stdout */
37 
void output_internal(const char *s, unsigned short nl) {
38 
  _asm {
39 
    mov ah, 0x02 /* AH=9 - write character in DL to stdout */
40 
    mov si, s
41 
    cld          /* clear DF so lodsb increments SI */
42 
    NEXTBYTE:
43 
    lodsb /* load byte from DS:SI into AL, SI++ */
44 
    mov dl, al
45 
    or al, 0  /* is al == 0? */
46 
    jz DONE
47 
    int 0x21
48 
    jmp NEXTBYTE
49 
    DONE:
50 
    or nl, 0
51 
    jz FINITO
52 
    /* print out a CR/LF trailer if nl set */
53 
    mov dl, 0x0D /* CR */
54 
    int 0x21
55 
    mov dl, 0x0A /* LF */
56 
    int 0x21
57 
    FINITO:
58 
  }
59 
}
388 mateuszvis 60 
 
61 
 
62 
/* find first matching files using a FindFirst DOS call
63 
 * returns 0 on success or a DOS err code on failure */
64 
unsigned short findfirst(struct DTA *dta, const char *pattern, unsigned short attr) {
65 
  unsigned short res = 0;
66 
  _asm {
67 
    /* set DTA location */
68 
    mov ah, 0x1a
69 
    mov dx, dta
70 
    int 0x21
71 
    /* */
72 
    mov ah, 0x4e    /* FindFirst */
73 
    mov dx, pattern
74 
    mov cx, attr
75 
    int 0x21        /* CF set on error + err code in AX, DTA filled with FileInfoRec on success */
76 
    jnc DONE
77 
    mov [res], ax
78 
    DONE:
79 
  }
80 
  return(res);
81 
}
82 
 
83 
 
84 
/* find next matching, ie. continues an action intiated by findfirst() */
85 
unsigned short findnext(struct DTA *dta) {
86 
  unsigned short res = 0;
87 
  _asm {
88 
    mov ah, 0x4f    /* FindNext */
89 
    mov dx, dta
90 
    int 0x21        /* CF set on error + err code in AX, DTA filled with FileInfoRec on success */
91 
    jnc DONE
92 
    mov [res], ax
93 
    DONE:
94 
  }
95 
  return(res);
96 
}
392 mateuszvis 97 
 
98 
 
99 
/* print s string and wait for a single key press from stdin. accepts only
100 
 * key presses defined in the c ASCIIZ string. returns offset of pressed key
101 
 * in string. keys in c MUST BE UPPERCASE! */
102 
unsigned short askchoice(const char *s, const char *c) {
103 
  unsigned short res;
104 
  char key = 0;
105 
 
106 
  AGAIN:
107 
  output(s);
108 
  output(" ");
109 
 
110 
  _asm {
111 
    push ax
112 
    push dx
113 
 
114 
    mov ax, 0x0c01 /* clear input buffer and execute getchar (INT 21h,AH=1) */
115 
    int 0x21
116 
    /* if AL == 0 then this is an extended character */
117 
    test al, al
118 
    jnz GOTCHAR
119 
    mov ah, 0x08   /* read again to flush extended char from input buffer */
120 
    int 0x21
121 
    xor al, al     /* all extended chars are ignored */
122 
    GOTCHAR:       /* received key is in AL now */
123 
    mov [key], al  /* save key */
124 
 
125 
    /* print a cr/lf */
126 
    mov ah, 0x02
127 
    mov dl, 0x0D
128 
    int 0x21
129 
    mov dl, 0x0A
130 
    int 0x21
131 
 
132 
    pop dx
133 
    pop ax
134 
  }
135 
 
136 
  /* ucase() result */
137 
  if ((key >= 'a') && (key <= 'z')) key -= ('a' - 'A');
138 
 
139 
  /* is there a match? */
140 
  for (res = 0; c[res] != 0; res++) if (c[res] == key) return(res);
141 
 
142 
  goto AGAIN;
143 
}
144 
 
145 
 
146 
/* converts a path to its canonic representation */
147 
void file_truename(const char *src, char *dst) {
148 
  _asm {
149 
    mov ah, 0x60  /* query truename, DS:SI=src, ES:DI=dst */
150 
    push ds
151 
    pop es
152 
    mov si, src
153 
    mov di, dst
154 
    int 0x21
155 
  }
156 
}
157 
 
158 
 
159 
/* returns DOS attributes of file, or -1 on error */
160 
int file_getattr(const char *fname) {
161 
  int res = -1;
162 
  _asm {
163 
    mov ax, 0x4300  /* query file attributes, fname at DS:DX */
164 
    mov dx, fname
165 
    int 0x21        /* CX=attributes if CF=0, otherwise AX=errno */
166 
    jc DONE
167 
    mov [res], cx
168 
    DONE:
169 
  }
170 
  return(res);
171 
}